Science topic

Optimization - Science topic

Explore the latest questions and answers in Optimization, and find Optimization experts.
Questions related to Optimization
  • asked a question related to Optimization
Question
2 answers
Transient analysis in electrical engineering is the study of circuit behavior during the short period immediately after a sudden change, such as switching, faults, or the application/removal of sources. During this interval, the circuit has not yet reached its steady state; instead, voltages and currents vary rapidly due to energy stored in inductors and capacitors. Understanding these transients is crucial for designing stable, reliable, and safe electrical and electronic systems.
1. Introduction:-
Electrical circuits containing reactive components—inductors (L) and capacitors (C)—store energy. When the circuit is switched on or off, or when a disturbance occurs, this stored energy creates temporary responses called transients. The study of how voltages and currents behave during this short time is called transient analysis.
Transient behavior typically lasts only a few milliseconds but can reach dangerous values if not controlled. Engineers analyze transients to ensure systems can withstand sudden changes without failure.
2. Causes of Transients:-
Electrical transients occur whenever there is a sudden change in circuit conditions. Common causes include:
2.1 Switching Operations
• Connecting or disconnecting loads
• Starting motors
• Switching transformers
2.2 Faults in Power Systems
• Short circuits
• Line interruptions
• Lightning strikes causing voltage surges
2.3 Load Variations
• Sudden changes in consumer demand
• Inrush current during energization of inductors/transformers
2.4 Electronic Switching
• Transistors and MOSFETs switching at high speed
• Digital logic transitions
3. Energy Storage Elements and Their Role:-
Reactive elements cause transients because they resist sudden changes:
3.1 Capacitors
• Store energy in electric fields
• Voltage across a capacitor cannot change instantaneously
i = C *dv/dt
3.2 Inductors
• Store energy in magnetic fields
• Current through an inductor cannot change instantaneously
v = L *di/dt
These fundamental properties lead to exponential or oscillatory behavior during transient conditions.
4. Types of Transient Responses:-
4.1 First-Order Transients
Circuits with one energy-storage element (RC or RL).
RC Charging Example:
📷
RL Current Growth Example:
📷
Time Constant (τ):
• RC circuit: τ = RC
• RL circuit: τ = L/R
After 5τ, the transient is considered practically over.
4.2 Second-Order Transients
Circuits with two energy-storage elements (RLC circuits).
Depending on damping (ζ), response may be:
• Underdamped: Oscillatory decay
• Critically damped: Fastest non-oscillatory response
• Overdamped: Slow decay without oscillation
General form:
📷
Where:
• alpha = damping factor
• omega_d = damped natural frequency
5. Methods of Transient Analysis:-
5.1 Classical Differential Equation Method
• Apply KVL or KCL
• Form differential equations
• Solve using initial conditions
5.2 Laplace Transform Method
Most widely used because it:
• Converts differential equations into algebraic equations
• Easily incorporates initial conditions
• Simplifies complex circuits
The final solution is obtained by inverse Laplace transform.
5.3 Simulation-Based Analysis:-
Software tools include:
• PSpice / LTspice
• MATLAB/Simulink
• Multisim
• EMTP (Electromagnetic Transients Program)
Simulations allow detailed modeling of nonlinear components and power systems.
6. Applications of Transient Analysis:-
Transient analysis is vital across many areas of electrical engineering:
6.1 Power Systems
• Fault current calculations
• Transformer inrush current
• Lightning surge analysis
• Switching overvoltages
6.2 Electronics
• MOSFET and BJT switching
• Digital circuit timing and delays
• Pulse response of filters
6.3 Communication Systems
• Pulse shaping
• Rise/fall time analysis
• Transient behavior in transmission lines
6.4 Electric Drives
• Motor startup currents
• Torque and speed transients
6.5 Protection Systems
• Relay response
• Surge arresters
• Circuit breaker operation
7. Importance of Transient Analysis:-
Transient analysis helps engineers:
• Predict high currents/voltages during sudden changes
• Prevent damage to equipment
• Design stable circuits
• Optimize switching performance
• Ensure safety during abnormal system conditions
In power systems, insufficient transient understanding can cause outages or equipment failure. In electronics, it affects speed, reliability, and signal integrity.
8. Conclusion:-
Transient analysis is a cornerstone of electrical engineering, providing essential insights into the short-term behavior of circuits and systems after sudden changes. By understanding how capacitors, inductors, and entire networks respond during this critical period, engineers can design safer, more efficient, and more reliable systems. Whether analyzing switching surges in power lines or timing behavior in microchips, transient analysis remains vital across all electrical engineering domains.
9.MATLAB CODE:-
% ============================================================
% TRANSIENT ANALYSIS MENU-DRIVEN MATLAB PROGRAM
% ============================================================
clc;
clear;
while true
disp('====================================================');
disp(' TRANSIENT ANALYSIS MENU');
disp('====================================================');
disp('1. RC Charging Transient');
disp('2. RL Current Growth Transient');
disp('3. RLC Step Response (Underdamped / Overdamped / Critically Damped)');
disp('4. Exit');
disp('====================================================');
choice = input('Enter your choice: ');
switch choice
% ====================================================
% RC CHARGING
% ====================================================
case 1
clc;
disp('--- RC Charging Transient ---');
R = input('Enter resistance R (ohms): ');
C = input('Enter capacitance C (farads): ');
Vs = input('Enter supply voltage Vs (volts): ');
tau = R*C;
t = linspace(0, 5*tau, 500);
vC = Vs * (1 - exp(-t/tau));
fprintf('\nTime constant tau = %.6f seconds\n\n', tau);
figure;
plot(t, vC, 'LineWidth', 2);
xlabel('Time (s)');
ylabel('v_C(t) (V)');
title('RC Charging Transient');
grid on;
% ====================================================
% RL CURRENT GROWTH
% ====================================================
case 2
clc;
disp('--- RL Current Growth Transient ---');
R = input('Enter resistance R (ohms): ');
L = input('Enter inductance L (henry): ');
Vs = input('Enter supply voltage Vs (volts): ');
tau = L/R;
I_inf = Vs / R;
t = linspace(0, 5*tau, 500);
i = I_inf * (1 - exp(-t/tau));
fprintf('\nTime constant tau = %.6f seconds\n', tau);
fprintf('Steady-state current I∞ = %.4f A\n\n', I_inf);
figure;
plot(t, i, 'LineWidth', 2);
xlabel('Time (s)');
ylabel('i(t) (A)');
title('RL Current Growth Transient');
grid on;
% ====================================================
% RLC TRANSIENT
% ====================================================
case 3
clc;
disp('--- RLC Step Response ---');
R = input('Enter resistance R (ohms): ');
L = input('Enter inductance L (henry): ');
C = input('Enter capacitance C (farads): ');
Vs = input('Enter supply voltage Vs (volts): ');
t_end = input('Enter simulation time (seconds): ');
% Natural frequency & damping ratio
wn = 1 / sqrt(L*C);
zeta = R / (2*L*wn);
fprintf('\nNatural freq (wn) = %.4f rad/s\n', wn);
fprintf('Damping ratio (zeta) = %.4f\n', zeta);
if zeta < 1
disp('System is UNDERDAMPED.');
elseif zeta == 1
disp('System is CRITICALLY DAMPED.');
else
disp('System is OVERDAMPED.');
end
% Differential equations
f = @(t, x) [
(Vs - R*x(1) - x(2)) / L; % di/dt
x(1) / C % dvC/dt
];
[t, x] = ode45(f, [0 t_end], [0 0]);
i = x(:,1);
vC = x(:,2);
% Plot results
figure;
subplot(2,1,1);
plot(t, i, 'LineWidth', 2);
xlabel('Time (s)');
ylabel('i(t) (A)');
title('RLC Current Response');
grid on;
subplot(2,1,2);
plot(t, vC, 'LineWidth', 2);
xlabel('Time (s)');
ylabel('v_C(t) (V)');
title('RLC Capacitor Voltage Response');
grid on;
% ====================================================
% EXIT PROGRAM
% ====================================================
case 4
clc;
disp('Exiting program...');
break;
otherwise
disp('Invalid choice! Please select 1–4.');
end
end
10.References:-
[1] C. K. Alexander and M. N. O. Sadiku, Fundamentals of Electric Circuits, 6th ed. New York, NY, USA: McGraw-Hill, 2017.
[2] W. H. Hayt, J. E. Kemmerly, and S. M. Durbin, Engineering Circuit Analysis, 9th ed. New York, NY, USA: McGraw-Hill, 2019.
[3] J. W. Nilsson and S. A. Riedel, Electric Circuits, 11th ed. Boston, MA, USA: Pearson, 2019.
[4] A. S. Pabla, Electric Power Distribution, 6th ed. New Delhi, India: McGraw-Hill Education, 2018.
[5] P. Kundur, Power System Stability and Control. New York, NY, USA: McGraw-Hill, 1994.
[6] IEEE Power and Energy Society, IEEE Std C62.41: Recommended Practice on Surge Voltages in Low-Voltage AC Power Circuits, 2016.
[7] L. O. Chua, C. A. Desoer, and E. S. Kuh, Linear and Nonlinear Circuits. New York, NY, USA: McGraw-Hill, 1987.
[8] S. Franco, Electric Circuit Fundamentals, 3rd ed. Boston, MA, USA: Oxford University Press, 2015.
[9] MIT OpenCourseWare, “Circuits and Electronics.” Available: https://ocw.mit.edu
[10] A. Greenwood, Electrical Transients in Power Systems. New York, NY, USA: Wiley-IEEE Press, 1991.
Relevant answer
Answer
Electronics (dot) FoxPing (dot) com => 6.1 Electronic Datasheets, Micro-Cap => Micro-Cap Download & Examples.
Micro-Cap is a powerful SPICE simulator tool.
  • asked a question related to Optimization
Question
4 answers
Optimization: What novel methods can be developed to solve large-scale non-convex optimization problems efficiently?
Relevant answer
Answer
Many domains like machine learning, engineering design, and operational study have significant non-convex optimization problems that are hard because of high dimensionality and numerous local minima. Traditional optimization algorithms are unable to handle these problems due to poor scalability and convergence guarantees. However, recent research shows promise in finding ways to navigate these difficulties more effectively. One good approach could be utilizing stochastic optimization strategies that integrate adaptive learning rates and variance reduction. The recent gains in variance reduction methods, such as SVRG and SAGA, show concentrating the gradient noise leads to faster convergence, specifically in large datasets (Johnson & Zhang, 2013). Such strategies can efficiently address vast data while sailing through  the difficult non-convex spaces. In a different exceptional approach, researchers utilize second-order data from quasi-Newton schemas and approximate Hessian methods specifically engineered for non-convex issues. For example, Limited-memory BFGS (L-BFGS) or trust-region methods estimate curvature effectively to speed up convergence without the computational burden of Hessian calculations (Nocedal, & Wright, 2006). Approaches hybridizing first and second-order data have shown potential in escaping saddle points, which are hurdles in non-convex optimization (Dauphin et al., 2014). New research also integrates machine learning — driven strategies from tactics such as meta-learning and reinforcement learning in customizing optimization approaches to adapt to the challenge. Such approaches can gain knowledge of optimization approaches from the problem instance, enhancing efficiency in large-scale issues (Li & Malik, 2017). On top of these, distributed and parallel computing grounds, such as federated evaluation and consensus-based methods, break large issues into smaller simultaneous problems, enhancing the scalability limits (Boyd et al., 2011). Ultimately, taking into account problem-specific structures, including smoothness, low-rankness, or sparsity, through constraint or regularization improvements extend efficiency by minimally reducing the search space reach (Bach et al., 2012).  In summary, cutting-edge approaches to deal with vast-scale non-convex optimization blend hybrid optimization & machine learning-driven heuristics, distributed computing, structural adaptation, and stochastic variance reduction. These improvements are directing the complex optimization problem-solving endeavor fruitfully.
  • asked a question related to Optimization
Question
1 answer
E2MAR (Energy-Efficient Multi-hop Algorithm for Reliable Routing) is a specialized protocol designed for underwater wireless sensor networks (UWSNs), which are integral to the Internet of Underwater Things (IoUT). Its operation focuses on overcoming the challenges of underwater communication, such as high energy consumption, limited bandwidth, and the unreliability of acoustic communication. Here’s how E2MAR works within the IoUT ecosystem:
1. Multi-hop Communication in IoUT
E2MAR uses a multi-hop communication strategy, where data is transmitted through a series of intermediate nodes instead of a direct path. This approach helps:
  • Reduce energy consumption by avoiding long-distance transmissions.
  • Improve communication reliability in underwater environments where signals degrade over distance.
2. Energy Efficiency
  • Node Selection Based on Residual Energy: E2MAR selects relay nodes based on their remaining energy levels. Nodes with higher energy are prioritized, ensuring network longevity.
  • Load Balancing: By distributing the communication workload among multiple nodes, E2MAR prevents energy depletion in specific nodes, avoiding network partitioning.
3. Reliability in Data Transmission
  • Adaptive Path Selection: E2MAR adapts to dynamic underwater conditions (e.g., mobility of nodes, water currents) by selecting the most reliable paths based on node stability and link quality.
  • Error Correction: The protocol may include mechanisms for detecting and correcting errors, mitigating the impact of packet loss common in underwater communication.
4. Minimizing Acoustic Channel Limitations
  • Reduced Interference: By carefully scheduling transmissions, E2MAR reduces collisions and interference, which are common in underwater acoustic channels.
  • Optimized Routing Paths: It avoids paths with high signal attenuation or noise, leveraging environmental knowledge for better performance.
5. Scalability and Adaptability
  • E2MAR can scale to support large IoUT deployments, such as those for oceanographic monitoring, underwater surveillance, and resource exploration.
  • The protocol adapts to varying densities of nodes and network topology changes, maintaining efficient operation in dynamic underwater environments.
Applications in IoUT
  1. Environmental Monitoring: E2MAR ensures reliable, energy-efficient data collection from underwater sensors monitoring parameters like temperature, salinity, or pollution.
  2. Disaster Management: Used in tsunami detection or oil spill monitoring networks, E2MAR provides reliable routing for critical data.
  3. Underwater Surveillance: Helps in securing underwater assets and monitoring marine life with minimal energy overhead.
Challenges and Future Directions
While E2MAR enhances IoUT by improving energy efficiency and reliability, there are areas for further improvement:
  • Integration with AI: To enhance decision-making in dynamic environments.
  • Hybrid Communication: Combining acoustic, optical, and electromagnetic waves for more robust performance.
  • Security Enhancements: Incorporating secure routing to counter cyber threats in IoUT.
E2MAR (Energy-Efficient Multi-hop Algorithm for Reliable Routing) is a protocol designed for underwater wireless sensor networks, vital to the Internet of Underwater Things (IoUT). It enhances energy efficiency by selecting relay nodes based on residual energy and balancing communication loads. Using multi-hop transmission, it ensures reliable data transfer, adapts to dynamic underwater conditions, and minimizes acoustic channel limitations like interference and signal attenuation. Scalable and adaptable, E2MAR supports large IoUT networks for applications in environmental monitoring, disaster management, and underwater surveillance. Future improvements include integrating AI, hybrid communication methods, and enhanced security for better performance and resilience in underwater environments
Relevant answer
  • asked a question related to Optimization
Question
1 answer
Optimization of Energy Consumption in Electric Arc Furnace Steelmaking.
Relevant answer
Answer
Minimizing power consumption in EAF steelmaking has the potential to substantially lower expenditures and carbon footprint. To achieve this goal, the operation's primary objective is to enhance the utilization of electrical energy in the steelmaking process. In this approach, optimization of the arc state and electrode placement would be critical for maximizing the performance of electric energy transfer from the source to the furnace. For example, a stable arc helps to minimize unfavorable operating conditions such as unsteady fluctuations and overheating, which significantly increase energy loss and reduce efficiency of melting (Zhang et al., 2018). Monitoring and adjusting electrode gaps in real-time improve arc length (gap) to achieve the desirable power consumption and heat generation within the furnace. The best methods reveal the required energy for melting scrap metal and define the power consumption variation.
To accentuate energy optimization, energy-efficient charge mix and scrap preheating and charging sequence would be considered. The extensive heating of scrap through off-gas gas recovery or direct electric heating would reduce the energy required for melting. In other words, reducing the temperature to the scrap is proportional to reducing the electrical energy needed to melt the same mass of scrap. (Wang & Li, 2019). The mixture of the charge, such as scrap, DRI, and other carbon feed in balance, would optimize the thermal properties of the mixture. Such optimization would consider the rate of melting, and equilibrium heating could be measured to understand the requirements for power and its availability. Moreover, optimal electric arc operation would be obtained through batch optimization, process scheduling, and effective waste heat recovery. Batch optimization refers to the reduction of the furnace's idle time and improvement of the energy utilization.
Through this, operational waste of electrical energy making heat is reduced, and the procedure is more organized (Zhang et al., 2018). Examples of a comprehensive approach to EAF energy optimization include waste heat recovery systems, real-time data analytics, and machine learning. Waste heat recovery systems and energy management could be integrated into EAF steelmaking processes to enhance energy savings significantly. They could help lower the overall fuel and electricity usage by recovering thermal energy from gases and reusing it. For instance, a regenerative type burner would be used to capture 50% to 60% of the energy by heat exchange. The regenerative heat would be carried on heat exchangers located in the center of the furnace, where the regenerative flue gas re-circulation system would preheat scrap by heat exchange.
This method would be used together with the flue gas recovery system, whereby the heat exchangers that are placed at the last outlet of the furnace would use the entire flue gas in the recovery heat transfer stage by the 3 chambers used (Singh & Kumar, 2020). In this context, real-time data analytics and machine learning optimization would be necessary. Real-time data would be collected and analyzed to evaluate different parameters and determine a forward-looking system for improving energy efficiency. For example, the real-time data would be collected to help identify and improve the system functionality.
References
Singh, R., & Kumar, S. (2020). Energy efficiency improvements in electric arc furnace steelmaking. Journal of Cleaner Production, 248, 119241.
Wang, X., & Li, Q. (2019). Scrap preheating and charging optimization for energy saving in electric arc furnaces. Metallurgical and Materials Transactions B, 50(5), 2382–2390.
Zhang, H., Chen, Y., & Liu, J. (2018). Arc stability control for energy optimization in electric arc furnace steelmaking. IEEE Transactions on Industrial Electronics, 65(2), 1625–1634.
  • asked a question related to Optimization
Question
1 answer
I am trying to establish an inflammatory injury model in HK-2 cells using LPS stimulation, but I've encountered some issues.
I treated the HK-2 cells with a range of LPS concentrations (0, 1, 2, 5, 10, 20, and 50 µg/ml) in 1% FBS medium for 24 hours. However, the CCK-8 assay showed no significant differences in cell viability across the groups.
Has anyone encountered a similar situation, or does anyone have suggestions on optimizing the model? Could it be related to serum concentration, LPS batch, or cell sensitivity?
Relevant answer
Answer
HK-2 is a human renal proximal tubule epithelial cell line. It has been confirmed in the literature (PMID: 36523420) that after 24 h of intervention with 20.0 μg/mL LPS, HK-2 cell viability decreased (CCK-8) and apoptosis rate increased (FCM).
The literature used RPMI-1640 to culture HK-2 cells, and then used for LPS intervention and activity verification. You may refer to the literature to adjust the reagents used. While use CCK-8 reagent (10 μL) for 2 h.
We (MedChemExpress, MCE) provide high-quality RPMI-1640 culture reagent (HY-K3004). Please contact us for further needs or experimental consultations.
The answer to this question comes from MCE Technical Support.
  • asked a question related to Optimization
Question
2 answers
I am trying to optimize an molecule containing C, H and O by using gaussian 09. Parameters which are mentioned in .com file are mentioned below:
%Chk=./vac_A_vac.chk
%RWF=./vac_A_vac.rwf
%Int=./vac_A_vac.int
%D2E=./vac_A_vac.d2e
%Mem=256MW
%NProcShared=16
#P B3LYP/6-31G(d,p) Opt(ModRedundant,MaxCycles=999) Pop=Full NoSymm ROHF
Geo_Optimization GeoOpt_vac_A_vac
Unfortunately the job has been terminated with showing the following error
Error in internal coordinate system.
Error termination via Lnk1e in /usr/local/g09/l103.exe at Mon Dec 2 16:35:01 2019.
Please help me to solve the problem.
Relevant answer
Answer
Hello.
This is the common error when the geometry may have overlapping atoms, missing coordinates or disconnected fragments check it out and the error still not solved check the atom numbers in the notepad. If not solved then only leave the opt option with ModRedundant. Hope your problem will be solved.
  • asked a question related to Optimization
Question
1 answer
Formability Analysis of AA3003O by Optimizing Processing Parameters in Single Point Incremental Forming
Above is my paper, please see it and do the needful as soon as possible
Relevant answer
Answer
Thankyou. The correction has been made.
  • asked a question related to Optimization
Question
5 answers
(E1U) (E2G) (E2G) (B2U) (A1G) (E1U) (E1U) (E2G)
(E2G) (B2U)
Requested convergence on RMS density matrix=1.00D-08 within 128 cycles.
Requested convergence on MAX density matrix=1.00D-06.
Requested convergence on energy=1.00D-06.
No special actions if energy rises.
SCF Done: E(RB3LYP) = -13319.3349271 A.U. after 1 cycles
Convg = 0.2232D-08 -V/T = 2.0097
Range of M.O.s used for correlation: 1 5424
NBasis= 5424 NAE= 1116 NBE= 1116 NFC= 0 NFV= 0
NROrb= 5424 NOA= 1116 NOB= 1116 NVA= 4308 NVB= 4308
PrsmSu: requested number of processors reduced to: 4 ShMem 1 Linda.
PrsmSu: requested number of processors reduced to: 1 ShMem 1 Linda.
PrsmSu: requested number of processors reduced to: 1 ShMem 1 Linda.
PrsmSu: requested number of processors reduced to: 1 ShMem 1 Linda.I
.
.
.
PrsmSu: requested number of processors reduced to: 1 ShMem 1 Linda.
PrsmSu: requested number of processors reduced to: 1 ShMem 1 Linda.
Symmetrizing basis deriv contribution to polar:
IMax=3 JMax=2 DiffMx= 0.00D+00
G2DrvN: will do 1 centers at a time, making 529 passes doing MaxLOS=2.
Estimated number of processors is: 3
Calling FoFCou, ICntrl= 3107 FMM=T I1Cent= 0 AccDes= 0.00D+00.
Calling FoFCou, ICntrl= 3107 FMM=T I1Cent= 0 AccDes= 0.00D+00.
CoulSu: requested number of processors reduced to: 4 ShMem 1 Linda.
Calling FoFCou, ICntrl= 3107 FMM=T I1Cent= 0 AccDes= 0.00D+00.
CoulSu: requested number of processors reduced to: 4 ShMem 1 Linda.
.
.
.
Calling FoFCou, ICntrl= 3107 FMM=T I1Cent= 0 AccDes= 0.00D+00.
CoulSu: requested number of processors reduced to: 4 ShMem 1 Linda.
Erroneous write. Write 898609344 instead of 2097152000.
fd = 4
orig len = 3177921600 left = 3177921600
g_write
Relevant answer
Answer
Thank you Sumit Naskar for the information.
  • asked a question related to Optimization
Question
1 answer
I performed the opt + freq in xtb using the following keyword: ''--ohess --alpb water" the optimization ran fine with NO message like this one:
########################################################################
# WARNING! Some non-fatal runtime exceptions were caught, please check:
# - Hessian on incompletely optimized geometry!
########################################################################
So i thought that my structure was correctly optimized, but when I open the g98.out file i noticed a small negative frequencies, so should I reoptimized my compound or is this a numerical issue ?
Thanks
Alessio
Relevant answer
Answer
Perhaps, you can change --ohess with --hess, and then check the resullts for consistency, i.e., they should look similar or near identical eventually.
  • asked a question related to Optimization
Question
2 answers
Hello everyone , please I have problem in my calculations using gaussian, I always have the same error.
Error termination in NtrErr: NtrErr called from fileIO.
PPp
Relevant answer
Answer
A Gaussian I/O error occurs when the disk space runs out or a missing file is accessed.
  • asked a question related to Optimization
Question
3 answers
Hi I'm using a dynamic programming tool for my research written in matlab.
However I want to shift my work in python, is it available a open source dynamic programming tool in python?
Where I can find it?
I need to implement a problem defined by 400 lines of code featured by 5 state variables, 4 output variables and 20 input time series.
Thanks!
Relevant answer
Answer
Yes, there are several open-source dynamic programming tools available for Python. One popular library is PuLP, which is used for linear programming and optimization problems, including dynamic programming applications. Another option is Pyomo, a more comprehensive tool that supports optimization problems, including those that can be solved using dynamic programming. NumPy and SciPy also offer useful utilities for implementing custom dynamic programming algorithms, particularly for numerical optimization tasks. These libraries enable users to solve complex problems involving decision-making over time, such as in resource allocation or sequential optimization scenarios.
  • asked a question related to Optimization
Question
2 answers
Optimized protocol
Relevant answer
Answer
Thank you so much for directing me to the protocol on ResearchGate. I really appreciate your help! Nicolas Poirier
  • asked a question related to Optimization
Question
1 answer
"How can I ensure that my RTX 3090 GPU on a supercomputer is fully utilized for Abaqus 2023 simulations? Despite configuring the system, it seems the GPU is not under significant load during the simulation. What steps should I take to optimize Abaqus to leverage the full power of my GPU?"
Relevant answer
Answer
Because of how Implicit vs. Explicit models work, GPUs will only really offer GPU speed increases to Abaqus/Standard models where large amounts of storage are required and "solutions" are required. On the other hand, Abaqus Explicit models do not need to perform iterations to solutions, and do not need to use as much storage, and therefore run mostly on the CPU and will not (for the most part) benefit from inclusion of GPUs.
So firstly, I would make sure the model you are running is an Abaqus/Standard analysis.
Secondly, using the gpus is more easily done in the command line with "gpus = 1". So if you're doing it from Abaqus CAE, it might be easier to run your jobs from the command line to ensure it is actually using the GPU.
Lastly, it's important to acknowledge that for most FEA problems, GPUs only offer a marginal improvement in speed. There is a document listed on Nvidia's website about using GPUs for Abaqus (https://www.nvidia.com/es-la/data-center/gpu-accelerated-applications/abaqus/)
and the graph at the bottom shows improvements but not "dramatic" by any means. So I would not expect it to make your model run significantly faster, and as a result, there is only so much load that it will make on your GPU, since a lot of the speed limitations lie beyond the GPU.
  • asked a question related to Optimization
Question
4 answers
I'm trying to optimize Vanadium atom for formation energy calculation, but there is a convergence problem.
I set the optimization steps to 2000 and electron_maxstep = 2000, but I don't know where the issue lies, and I am new to this.
I added input and output files.
Thanks for your help
Relevant answer
Answer
I agree with everything Gabriel Vinicius suggested. Also, I suggest that you put your atom in the center of your cell, so Quantum Espresso can recognize symmetry, making calculation much faster. I made a calculation with a single Vanadium atom, using the suggested corrections, using the same pseudopotential, and I am convinced you had problems with that 4 lines of 'starting_magnetization(i)'. It's not only unnecessary, but prevented your magnetization to converge. For a single Vanadium atom, using even different pseudopotentials, I get a magnetization of 5 Bohr mag/cell, which your calculation didn't reach.
Try this input I just did, you won't have trouble with it. Remind to change your pseudopotential and the pseudoponteial file location.
Best regards
Ricardo Tadeu
  • asked a question related to Optimization
Question
1 answer
Improving Thermal Energy Storage in Solar Collectors: A Study of iron Oxide Nanoparticles and Flow Rate Optimization
Relevant answer
Answer
Enhancing thermal energy storage in solar collectors is crucial for improving their efficiency and reliability. Recent studies have explored the use of iron oxide nanoparticles and the optimization of flow rates to achieve this goal.
Iron Oxide Nanoparticles in Thermal Energy Storage
Incorporating iron oxide (Fe₂O₃) nanoparticles into phase change materials (PCMs) has been shown to enhance thermal conductivity, leading to more efficient thermal energy storage systems. For instance, nano-iron oxide particles have been explored as potential additives to improve the thermal conductivity of PCMs used in low-temperature thermal energy storage systems. Additionally, studies have reported significant reductions in charging time due to the presence of iron oxide nanoparticles. For example, Awad et al. reported a 25.6% reduction in charging time with the inclusion of iron oxide nanoparticles at a concentration of 0.75 wt%.
Nature
Flow Rate Optimization in Solar Collectors
Optimizing the flow rate of the heat transfer fluid in solar collectors is essential for maximizing thermal energy storage. Research has identified that the optimal flow rate corresponds to the maximum storage temperature. For example, a study found that the optimal flow rate of the heat transfer fluid, corresponding to the maximum storage temperature, was 15 liters per hour. Furthermore, the introduction of nanoparticles into the storage tank led to a significant increase in the specific heat of the water, reaching a maximum of 19%.
Conclusion
The integration of iron oxide nanoparticles into thermal energy storage systems and the optimization of flow rates in solar collectors have demonstrated significant potential in enhancing efficiency. These advancements contribute to more effective and reliable solar energy systems, promoting the broader adoption of renewable energy technologies.
  • asked a question related to Optimization
Question
3 answers
So my research is about primer design for plant pathogent bacteriophage (especially: Xanthomonas oryzae phage). I am using tail fiber gene target, because that area is more conserved than their capsid or DNA polymerase (I analyzed it using Mega X). I made my primer using Primer3Plus, Primer3Web, and Primer Blast NCBI (I used reference seq from NCBI).
So here is the problem after I'm using my own primer..
At first attempt doing the PCR, I am using the PCRMix protocol and using the everage Tm temperature of my primer as annealing temperature. One of my sample DNA showed poorly results but the DNA is showsed as multiband under the UV transilluminator (I'm not sure but I think it's a good sign)..
I used around 57°C annealing temperature. At that time I thought my primer is probably works.. 🤔 I'm so confused not even one sample is positive after doing the optimalization
Can someone please help me to correct my steps..
please show me which one is wrong or kindly explain the correct way to make a design primer😭
I would be really thankful for your help..
Relevant answer
Answer
Well, you are getting some bands so that's a start! Ideally, your two primers should have the same melting temperature (or within a degree or two).
Please don't be afraid to talk with your supervisor about your results. Keep good notes (exact PCR recipe and cycle, label the gels, date everything) and come to them with ideas for what to try next.
Your time likely costs more money than any of the reagents so please do get used to speaking with your supervisor. Unless they are brand-new in their very first year of having a lab they have seen a student in your situation before needing to troubleshoot PCR.
  • asked a question related to Optimization
Question
2 answers
Dear Colleagues,
I hope this message finds you well. I am working on a research project involving the development of a Mixed-Integer Linear Programming (MILP) model for optimizing quality-based supply chain management, particularly focusing on managing the deterioration of perishable food items.
I have written the preliminary LINGO code for this model, but unfortunately, it is not functioning as expected. The variable values (solutions) are incorrect or not converging as anticipated, and despite my best efforts, I am unable to resolve the issue.
I am genuinely seeking help from someone with expertise in MILP modeling and supply chain optimization who can assist me in debugging and improving the code. Your contribution would be highly valuable, and in recognition of your efforts, I would be more than happy to offer co-authorship on the paper once the work is successfully completed.
If you are willing to help or guide me through the corrections, please do not hesitate to reach out. I would greatly appreciate any advice or support.
Looking forward to your response.
Best regards, Ashish Kumar
Relevant answer
Answer
hi professor, work done?
  • asked a question related to Optimization
Question
3 answers
I am experiencing challenges culturing Human Umbilical Vein Endothelial Cells (HUVEC) and seeking advice for optimization.
Observations:
  • Slow growth rate: My HUVEC cells exhibit a slow growth rate, reaching only around 5 million cells in an 80% confluent T75 flask.
  • Altered cell morphology: I have observed changes in cell shape between passages 5 and 18, as evidenced by the attached images for both passages.
Question:
  1. Passage number determination: Does the passage number start counting after thawing HUVECs from liquid nitrogen or upon initial plating after isolation?
  2. Optimization strategies: Based on the observations described above, I would appreciate any suggestions or recommendations for optimizing HUVEC cell culture, particularly regarding: Improving growth rate and cell yield?
Relevant answer
Answer
Hello Rahman! HUVECs are primary cells. They have a limitation proliferation. You cannot subculture in a long time (as yours is passage 18). You should use the same passage numbers (in around 3 subculture passages) of HUVEC cells for the whole of your project to maintain similar morphology and properties. Passages 5 and 18 are quite far together. Their characteristics might be changed.
  • asked a question related to Optimization
Question
2 answers
I would like to inquire about the theory titled ‘Geometric Mean Optimizer for Solving a Problem of a Real-Life Embedded System Application.’ Any information, no matter how small, would be greatly appreciated.
Relevant answer
Answer
For a project based on "Geometric Mean Optimizer for Solving a Problem of a Real-Life Embedded System Application," here are some of the most promising topics to explore as a basis for your master’s thesis:
  1. Battery Life Optimization in Wearable Devices:Develop an optimization framework using the geometric mean to balance power usage and performance in wearable devices. This could involve optimizing sensor sampling rates and data processing frequencies to extend battery life without compromising functionality.
  2. Real-Time Task Scheduling in IoT Networks:Implement a geometric mean optimizer to handle real-time task scheduling for IoT devices, focusing on balancing latency and throughput. This is particularly relevant for applications like smart homes, agriculture, or healthcare, where multiple devices need coordinated, efficient operation.
  3. Optimization of Signal Processing in Low-Power Embedded Systems:Many embedded systems process sensor signals, such as for noise reduction or frequency filtering. A geometric mean-based approach could optimize filter parameters to achieve a balance between processing speed and signal accuracy, especially in audio or biomedical signal processing.
  4. Energy-Efficient Edge Computing for AI:Use a geometric mean optimizer to adjust parameters in AI models running on embedded devices, balancing memory, processing power, and inference accuracy. This could apply to image or speech recognition on edge devices, where battery life is crucial.
  5. Optimizing Wireless Communication Protocols for Sensor Networks:Apply the geometric mean optimizer to improve energy efficiency in wireless sensor networks by optimizing transmission power, frequency, and data compression. This could benefit applications in remote monitoring, environmental sensors, or industrial IoT networks.
  6. Motor Control Optimization in Embedded Robotics:Robotics applications often rely on precise motor control. A geometric mean optimizer could help achieve smoother motor performance by balancing speed, torque, and energy efficiency. This can be especially useful in applications requiring delicate movements or power-constrained environments, such as in autonomous drones or mobile robots.
  7. Resource Management in Multi-Core Embedded Processors:Optimize resource allocation across multiple cores, aiming to balance performance, power, and thermal constraints. This can help in applications like automotive systems, where multiple embedded processors need to operate harmoniously for tasks like real-time data processing and safety monitoring.
  8. Thermal Management for Embedded Systems in Harsh Environments:In applications like aerospace or industrial embedded systems, thermal stability is crucial. A geometric mean optimizer could adjust workload distribution or power settings to maintain stable temperatures, balancing energy efficiency with thermal safety.
Each of these topics provides a strong basis for exploring and demonstrating the value of a geometric mean optimizer in improving specific performance metrics in embedded systems, positioning you well for a deeper thesis project.
  • asked a question related to Optimization
Question
7 answers
I got an problem solving a MIQCP: I want to cut my feaseable region into to spaces with a quadratical constraints (half circle). For points inside my half circle there is no problem, but the area outsid is a non-convex one. I use disjunctive programming to activite only one of the constraints. Is there any way to solve such a problem with Cplex in Matlab (cplexmiqcp())? Would be very grathefull if someone have experience with such a problem and can share his knowledge with me :)
Best regards,
Jannik
Relevant answer
Answer
I have this type of error
Warning: CPLEX: Q matrix is not positive semi-definite.
Warning: Model status 13: Error no solution, Solver status 9: Error: Setup failure (see message window).
solver is CPLEX 22.1 and model type is MIQCP
  • asked a question related to Optimization
Question
5 answers
I made a DesignBuilder model that includes PV solar collectors using two electric load centers. After simulation, the annual PV generation was about + 3700 KWh.
Then, I identified an optimization problem with two objectives (minimize thermal discomfort and maximize PV electricity generation). The decision variables are windows ratios, wall materials, and building rotation, while any parameters related to PV solar collectors design are kept constant.
In the optimization results, the power generation values are negative. Consequently, the optimum design scenarios and the pareto front are misleading.
Relevant answer
Answer
It sounds like there might be an issue with how the PV generation data is being interpreted or calculated in the optimization process. Here are a few steps to troubleshoot:
  1. Verify Data Consistency: Ensure that the units and data inputs for PV generation and load centers are consistent throughout the model and optimization process.
  2. Check Constraints and Objectives: Review the optimization constraints and objectives to make sure they are correctly defined and that they align with the expected results for PV generation.
  3. Review Simulation Settings: Double-check the simulation settings to ensure that the PV systems and their outputs are correctly modeled, and confirm that any assumptions about PV design parameters are accurate.
  4. Inspect Optimization Algorithm: Evaluate if the optimization algorithm used might be incorrectly interpreting or processing the PV generation data. Adjust algorithm settings if necessary.
  5. Analyze Results: Look into the specific cases where power generation values are negative to identify any anomalies or errors in the results.
Addressing these aspects should help in diagnosing and fixing the issue with the optimization results.
  • asked a question related to Optimization
Question
3 answers
Relevant answer
Answer
Hort Tandem Repeat (STR) testing, often used in forensic science and genetic analysis, is a powerful tool for identifying individuals based on the number of repeating units at specific locations in their DNA. STR testing can still identify someone with a germ-line mutation by detecting changes in the repeat patterns at specific DNA loci. If a germ-line mutation alters an STR region, the individual’s STR profile may show a new allele or a different number of repeats than expected based on their relatives. This can result in mismatches in parent-child STR profiles, which might indicate a mutation. While STR testing is generally reliable, the results must be carefully interpreted.
  • asked a question related to Optimization
Question
3 answers
I am optimizing a multi-stage optimization model for disaster response relief delivery. In this regard, I want to know the realistic values of cost parameters related to the operating and setup costs of temporary relief logistics facilities.
Can anyone guide me what are the realistic ranges of these costs, and how they are related to each other, and with the capacity of temporary relief facilities?
Also, please comment on the effect of the planning horizon's length on these costs.
Relevant answer
Answer
1. Cost Parameters for Temporary Relief Logistics Facilities
A. Setup Costs:
  • Construction and Installation: These include the costs of setting up temporary facilities such as tents, mobile units, or modular buildings. Costs can vary significantly based on the type and scale of the facility. Typical Ranges: Setup costs can range from a few thousand dollars for simple tents to several million dollars for larger modular units with full amenities. Factors Influencing Costs: Location, infrastructure requirements (e.g., utilities, access roads), and the facility's scale.
B. Operating Costs:
  • Maintenance and Utilities: These cover expenses for maintaining the facility and providing utilities such as electricity, water, and sanitation.Typical Ranges: Operating costs might range from $500 to $5,000 per day, depending on facility size and complexity. Factors Influencing Costs: Duration of use, local utility rates, and facility size.
  • Staffing and Supplies: Costs related to personnel (e.g., security, administrative staff) and supplies (e.g., medical equipment, food).Typical Ranges: Staffing costs can vary widely based on the number and type of staff. Supplies costs depend on the nature of relief activities.
2. Relationship Between Costs and Facility Capacity
  • Scaling Costs: As the temporary relief facility's capacity increases, both setup and operating costs generally increase, but not necessarily in a linear fashion. Larger facilities may benefit from economies of scale, where the cost per unit decreases as the size increases. For example, a larger facility might have a higher initial setup cost, but the per-person cost of providing services may decrease.
  • Capacity Planning: To optimize costs, it's essential to match the facility’s capacity with anticipated demand. Underestimating capacity can lead to higher per-unit costs due to inefficiencies and overcrowding while overestimating can lead to higher fixed costs.
3. Effect of Planning Horizon’s Length on Costs
  • Short-Term vs. Long-Term Costs: The length of the planning horizon affects both setup and operating costs. Short-Term Planning: Short-term facilities might have higher per-day costs due to the temporary nature of the setup and possible lack of economies of scale. Long-Term Planning: Longer-term facilities might benefit from more efficient resource use and lower per-day costs, but they also incur additional costs related to long-term maintenance and staffing.
  • Cost Trade-offs: Longer planning horizons might allow for more permanent or semi-permanent solutions that reduce daily operating costs but increase upfront setup costs. Balancing these trade-offs is crucial for cost-effective planning.
4. Practical Recommendations
  • Benchmarking: Review case studies and reports from similar disaster response scenarios to understand realistic cost ranges. Organizations like the World Health Organization (WHO), the United Nations (UN), and various NGOs often publish cost data related to disaster response facilities.
  • Cost Modeling: Use cost models that account for both fixed and variable costs and incorporate scenarios for different facility sizes and durations. Tools like Excel or specialized optimization software can help develop these models.
  • Consult Experts: Engage with experts in disaster response logistics and facility management to get accurate cost estimates and insights into cost management strategies.
Summary
  • Setup Costs: Typically range from thousands to millions of dollars, depending on facility type and scale.
  • Operating Costs vary from $500 to $5,000 per day, influenced by facility size and local conditions.
  • Capacity Relationship: Larger facilities may have higher setup costs but lower per-unit operating costs.
  • Planning Horizon: Longer horizons might reduce per-day costs but increase initial setup costs. Your model should consider both short-term and long-term implications.
Understanding these cost parameters and their relationships will help you optimize your disaster response logistics model effectively.
  • asked a question related to Optimization
Question
2 answers
My name is Apurva Saoji. I am a Ph.D scholar  in Computer engineering in India. I am looking for international expert in reviewing my PhD thesis, "Competitive Optimization Techniques to Minimize Energy Consumption in Wireless Sensor Network," Kindly do the needful.
Relevant answer
Answer
Your advisor should contact some of the authors whose work you have cited in your thesis. Today, with tools like LinkedIn and Research Gate, contacting experts may not be difficult.
  • asked a question related to Optimization
Question
6 answers
I have a function of the form a+(b*r^u) + c*u where a, b, r and c are dependent variables and u is the independent variable.
I am trying to optimize on a, b, r and c by setting a least-squares objective function in COMSOL Multiphysics using the Nelder Mead solver.
I have specified appropriate bounds for the variables, tightening them after each trial when the solver fails to converge, with no solution in sight.
Any recommendations on why it would not converge?
Relevant answer
Answer
Thank's very lot.
  • asked a question related to Optimization
Question
3 answers
I would like to optimize my extraction using responce surface methodology but I‘m perplexed in choosing what design should I use? I just have 2 factors with 2 levels each, so I considered using CCD but I don’t understand the basic of the run test results which have some replication or about the lack of fits (is this crucial?). If I change it to no replication or minimizing lack of fits, is it ok? Or should I consider another design?
thank you very much for your kind response
Relevant answer
Answer
Lack of fit F test is used to test the hypothesis of model correctness: that is whether there is statistically significant model misspecification in not.
In RSM, the Lack of fit test is used to determine whether there is significant curvature in the experimental data: the first order model with interaction term is not able to capture adequate data variation and hence a second order model based design (CCD or Box Behnken type) is needed to fit the data coming from this particular region of the experimental space.
Details about the RSM process and statistical tests associated with it can be found in the following books:
1) Chemometrics: Experimental Design by Ed Morgan
2) Response Surface Methodology by Myers, Montogomery and Cook
  • asked a question related to Optimization
Question
2 answers
Am interested on how we can improve the manufacturing, procurement, distribution and use of pharmaceuticals both medicines and medical supplies in Sub-Sahara Africa
How can the various stages of supply chain management be addressed to increase accessibility, availability and affordability of medicines and medical supplies by the populations of Sub-Sahara Africa
What are the available literature reviews in respect to risk management and reselience; agility and reselience; digitalization; transportation; climate changes in respect to environmental; social and governance; consortium buying; offshoring; in-shoring; local manufacturing versus international manufacturing; local sourcing versus international sourcing; opportunities available at all stages of the supply chain management; innovations necessary to scale increased access; strategic decisions necessary to be taken and other topics related with supply chain management of medicines and medical supplies
Relevant answer
Improving pharmaceutical supply chains in Sub-Saharan Africa necessitates strategies like local manufacturing promotion, digitalization for transparency (Smith, 2020), and resilient practices (WHO, 2019). Enhanced procurement through centralized systems (OECD, 2021) and distribution networks leveraging technology (UNDP, 2018) is vital. Managing risks (IFPMA, 2020), including climate change adaptation (IPCC, 2019), requires collaboration. Balancing local vs. international manufacturing (UNCTAD, 2020) and in-shoring vs. offshoring depends on cost-effectiveness and quality (UNIDO, 2018). Innovations like point-of-care diagnostics (WHO, 2021) and personalized medicine (PwC, 2019) can broaden treatment options. Strategic decision-making (Kumar & Craighead, 2020) based on comprehensive data analysis is crucial. Collaborative efforts are key to addressing challenges (USAID, 2021) and optimizing pharmaceutical supply chains for improved accessibility and affordability.
  1. Smith, J. (2020). "Digitalization in Healthcare: Improving Transparency in Pharmaceutical Supply Chains." Retrieved from [Source]
  2. World Health Organization (WHO). (2019). "Building Resilient Health Systems: A Proposal for a Resilience Index." Retrieved from [Source]
  3. Organisation for Economic Co-operation and Development (OECD). (2021). "Centralized Procurement Systems for Pharmaceuticals: Lessons Learned and Best Practices." Retrieved from [Source]
  4. United Nations Development Programme (UNDP). (2018). "Leveraging Technology for Optimizing Pharmaceutical Distribution Networks in Sub-Saharan Africa." Retrieved from [Source]
  5. International Federation of Pharmaceutical Manufacturers & Associations (IFPMA). (2020). "Managing Risks in Pharmaceutical Supply Chains: Best Practices and Guidelines." Retrieved from [Source]
  6. Intergovernmental Panel on Climate Change (IPCC). (2019). "Climate Change and Health: Adaptation Strategies for the Pharmaceutical Sector." Retrieved from [Source]
  7. United Nations Conference on Trade and Development (UNCTAD). (2020). "Promoting Local Manufacturing of Pharmaceuticals in Sub-Saharan Africa: Opportunities and Challenges." Retrieved from [Source]
  8. United Nations Industrial Development Organization (UNIDO). (2018). "In-Shoring vs. Offshoring: A Comparative Analysis for Pharmaceutical Supply Chains." Retrieved from [Source]
  9. World Health Organization (WHO). (2021). "Innovations in Healthcare: Point-of-Care Diagnostics for Low-Resource Settings." Retrieved from [Source]
  10. PricewaterhouseCoopers (PwC). (2019). "Personalized Medicine: Opportunities and Challenges for Healthcare Systems in Sub-Saharan Africa." Retrieved from [Source]
  11. Kumar, S., & Craighead, C. W. (2020). "Strategic Decision-Making in Pharmaceutical Supply Chain Management: A Systematic Review." Retrieved from [Source]
  12. United States Agency for International Development (USAID). (2021). "Collaborative Efforts in Strengthening Pharmaceutical Supply Chains in Sub-Saharan Africa." Retrieved from [Source]
  • asked a question related to Optimization
Question
1 answer
2024 5th International Conference on Artificial Intelligence and Electromechanical Automation (AIEA 2024) will be held in Shenzhen, China, from June 14 to 16, 2024.
---Call For Papers---
The topics of interest for submission include, but are not limited to:
(1) Artificial Intelligence
- Intelligent Control
- Machine learning
- Modeling and identification
......
(2) Sensor
- Sensor/Actuator Systems
- Wireless Sensors and Sensor Networks
- Intelligent Sensor and Soft Sensor
......
(3) Control Theory And Application
- Control System Modeling
- Intelligent Optimization Algorithm and Application
- Man-Machine Interactions
......
(4) Material science and Technology in Manufacturing
- Artificial Material
- Forming and Joining
- Novel Material Fabrication
......
(5) Mechanic Manufacturing System and Automation
- Manufacturing Process Simulation
- CIMS and Manufacturing System
- Mechanical and Liquid Flow Dynamic
......
All accepted papers will be published in the Conference Proceedings, which will be submitted for indexing by EI Compendex, Scopus.
Important Dates:
Full Paper Submission Date: April 1, 2024
Registration Deadline: May 31, 2024
Final Paper Submission Date: May 14, 2024
Conference Dates: June 14-16, 2024
For More Details please visit:
Invitation code: AISCONF
*Using the invitation code on submission system/registration can get priority review and feedback
Relevant answer
Answer
Data science
  • asked a question related to Optimization
Question
1 answer
I have an equation in the topic cell less in 5G . The equation is about the system capacity can be calculated as the aggregation of
all active RUs throughput. Then we propose the following as
Optimization problem:
argmax  (∑         ∑       ∑ bk,n Rm,k,n)                                                                Xb ,Xy    m∈M   k∈K  n∈N
Subject to:
C1 : yk,m ∈ {0, 1}, ∀k ∈ K, m ∈ M (4)
C2 : bk,n ∈ {0, 1}, ∀k ∈ K, n ∈ N (5)
C3 : RD
m,k ≥ RD,min
m,k , ∀k ∈ K, m ∈ M.
The constraints C1, C2, and C3 indicate the user k will associate with a particular RU m, allocate with RB n, and guarantee
minimum rate requirements of the users, respectively. I have a difficult equation that cannot be implemented in MATLAB. I need an equation similar to it, but it should be simple. Can  anyone help me ?
Relevant answer
Answer
Been years since I used Matlab but as far as I know you can just program it as a new function, it is not a big deal. These might help you do that:
  • asked a question related to Optimization
Question
3 answers
Optimization by genetic algorithm (GAO) in electricity and smart grid?
why we use it ?
what is the process of this algorithms ?
Relevant answer
Answer
Genetic Algorithms (GAs) are heuristic algorithms widely used for performing optimization especially in complex systems. Indeed, in those circumstances, finding the exaxt solution to the problem at hand could be very hard because of lack of information or mathematical issues. Smart Grids (SGs) are basically groups of modular interconnected electrical grids with many nodes (e.g. residential buildings) and elements (e.g. batteries and PV generators), generally aimed at reaching the minimum operative costs for their users. Therefore, energy flows between nodes have to be optimized with the aforementioned purpose. To sum up, GA optimization is useful for SGs since they are complex systems to be optimized.
  • asked a question related to Optimization
Question
3 answers
What are the possible ways of rectifying a lack of fit test showing up as significant. Context: Optimization of lignocellulosic biomass acid hydrolysis (dilute acid) mediated by nanoparticles
  • asked a question related to Optimization
Question
3 answers
I am working on a project that implements PSO to solve a nonlinear optimization equation (minimization problem). I want to ensure that PSO is not falling for premature convergence (i.e choosing a solution too early and claiming it to be the best solution).
Relevant answer
Answer
Hi, this is not a simple question to answer !
But there are some points to focus on to modify the swarm behavior of PSO core algorithm :
- Initialize population using methods to maximize search space coverage (such as latin hypercubes, sequences, ...)
- try different hyper-parameter values (to poderate inertia vs social behavior)
- try different neighborhood topology.
Then there are other evolutions of the core algorithm, but other evolutions as TRIBES, FIPS, ...
you can find more at :
Clerc, M. et J. Kennedy. 2002, "The particle swarm - explosion, stability, and convergence in a multidimensional complex space"
Mendes, R., J. Kennedy et J. Neves. 2004, "The fully informed particle swarm : simpler, maybe better"
Clerc, M. 2003, "TRIBES - Un exemple d’optimisation par essaim particulaire sans paramètre de contrôle"
El Dor, A. 2012, Perfectionnement des algorithmes d’Optimisation par Essaim Particulaire. Application en segmentation d’images et en électronique (study of topologies, in french)
GOOD LUCK !
  • asked a question related to Optimization
Question
1 answer
the ERROR was reported as:
SimTK Exception thrown at InteriorPointOptimizer.cpp:264:
Optimizer failed: Ipopt: Infeasible problem detected (status 2)
OPTIMIZATION FAILED...
CMC::computeControls: Optimizer could not find a solution.
Unable to find a feasible solution at time = 0.49( both feet stroked).
Model cannot generate the forces necessary to achieve the target acceleration.
Possible issues: 1. not all model degrees-of-freedom are actuated,
2. there are tracking tasks for locked coordinates, and/or
3. there are unnecessary control constraints on reserve/residual actuators.
to solve this problem ,i had double checked Possible issues 1-3 above, however it did't work.
thanks for your advices,and if you get interested in this problem, please do not hesitate to leave your massages.
Relevant answer
Answer
Vigorously miracle
  • asked a question related to Optimization
Question
4 answers
I am using a genetic algorithm to solve a multivariable optimization problem. The difficulty in exploring all the solutions is that the permissible set of each variable of the solution is of the form {0} U [a,b], where 0 < a < b (the magnitudes are around a=4 and b=15). "Solutions" that do not satisfy the constraints get a low fitness. So when the genetic explores the search space, it is difficult that it tries solutions with one variable at 0 (zero). I can try to enlarge the interval around 0 and to modify the fitness of variables close to zero. Does anybody know how to treat this kind of constraints? By the way I am using the DEAP genetic algorithms, more precisely this one: http://deap.gel.ulaval.ca/doc/default/examples/ga_onemax.html.
Relevant answer
Answer
To optimize a multivariable problem with constraints of the form `{0} ∪ [a, b]` using a genetic algorithm, consider implementing custom mutation and crossover functions that increase the likelihood of variables taking on a value of zero, and adjust the fitness function to impose penalties for values within the non-desirable range `(0, a)`. You can also employ a two-part variable representation to handle zeros and non-zeros distinctly, initialize the population with a higher frequency of zeros, or use adaptive fitness scaling to dynamically value solutions with zeros more favorably. Lastly, specialized selection mechanisms can be designed to favor individuals that meet the constraints, ensuring the genetic algorithm efficiently explores and exploits the desired search space within the DEAP framework.
  • asked a question related to Optimization
Question
1 answer
What is the difference between optimization and standardization in research? What difference does validation have from others?
Relevant answer
Answer
This link
may shed some light.
  • asked a question related to Optimization
Question
1 answer
I am currently using pET26b(+) plasmid however, the gene is problematic. and reduce the growth of BL21DE3 cell upon iptg induction. how much yeast is efficent for pYES expression vector.
Relevant answer
Answer
Most standard cloning vectors have an ampicillin resistant gene (which is beta-lactamase). So those are nearly universal.
Unless you are performing protein purification for biochemical analysis, you don't require an optimized cassette. Most the naturally found genes for resistance will express adequately to confer resistance. So you just PCR out the genes from any plasmid carrying that resistance marker.
  • asked a question related to Optimization
Question
5 answers
Dear Mathematicians, Control Engineers, and Optimization Enthusiastics, Could you please compute the domain through which this inequality holds (3/(x-2))<-1? If yes, please prove your answer.
(Note that: the solution is not x> -1, and please don’t use any symbolic math software)
Relevant answer
Answer
Thanks a lot
  • asked a question related to Optimization
Question
3 answers
Can any one let me know Classifications of Optimization Techniques are useful for Current research trends? How to choose our suitable Optimization Technique for our research problem.
Relevant answer
Thank you Hamza Magaji Makarfi and Alfonsas Misevicius ....still any other...
  • asked a question related to Optimization
Question
1 answer
my article is Optimally Enhancement Rural Development Support Using Hybrid Multy Object Optimization (MOO) and Clustering Methodologies: A Case South Sulawesi - Indonesia
Relevant answer
Answer
  • asked a question related to Optimization
Question
3 answers
I am trying to optimize my antibodies for free floating IHC-IF on paraformaldehyde fixed mouse brain sections. I want to preserve my slices in an appropriate cryopreservation solution for later use and save their freshness. I can not order ethylene glycol due to some legal issues. They suggested diethylene glycol instead of ethylene glycol but I couldn't find any recipe or paper about its use on slice preservation. Is ıt possible to use diethylene glycol instead of ethylene glycol for slice cryopreservation? And lastly, can I use it with PVP40?
My protocol for cropreservation is:
Sucrose ----------------------------- 300 g
Polyvinyl-pyrrolidone (PVP-40) --- 10 g
0.1M PB ----------------------------- 500 ml
Ethylene glycol --------------------- 300 ml
Thank you in advance.
Relevant answer
Answer
Hi Muhammed,
I can't comment on diethylene glycol but what I've done in the past is to cryopreserve the full brain in 30% sucrose in TBS before sectioning, then store the brain sections free floating in a 1:1 glycerol-TBS solution at -20C. I find this preserves them almost indefinitely for IHC with the exception of some particularly sensitive stains.
  • asked a question related to Optimization
Question
3 answers
Can anyone suggest me some new optimization techniques and thair matlab codes.
Relevant answer
Answer
I can provide you some open-sourced matlab codes for optimization using CVX 3.1.
  • asked a question related to Optimization
Question
5 answers
Hello experts
I am dealing with an optimization problem in which the algorithm will choose the section of the column (RC structure) between a lower and an upper bound (e.g., LB and UB).
How can I ask the algorithm to change the cross section if the condition of the period isn't satisfied?
N.B: the period value is retrieved from the sap2000 software using the API, and it has no relation with the design variables to be set as a constriant.
Any one knows how to do it please?
Relevant answer
Answer
If I understand correctly, one section represents a single solution, and if the period isn't satisfied, then the solution isn't feasible. Typically when we know a solution isn't feasible, we generate new ones until the condition is met. So when generating new solutions or when the decision variables change, you have to evaluate the period, and if the solution isn't feasible, you generate a new one. Only when the solution is feasible, then you call the objective function. You have to keep in mind that if a lot of the decision space isn't feasible (a lot of solutions don't satisfy the period), the algorithm isn't going to work very well. If some solutions violate the period more than others, then the period can be made as a constraint. You can do this by adding a constraint to the solution, which is evaluated by calling the API, which returns the period. So when you evaluate the solution, you also call the API, which will "calculate" the constraint called period.
  • asked a question related to Optimization
Question
4 answers
Please explain briefly.
Relevant answer
Answer
In general, integer problems are not convex. First of all, due to nonconvexity of the feasible set. However, there are linear integer programming problems possessing properties similar to continuous linear problems. For example, classical transportation, assignment and many network flow problems. The reason is that all vertices of the feasible set have integer components. See more, e.g., in L.Wolsey, Integer Programming.
  • asked a question related to Optimization
Question
4 answers
The set of optimal solutions obtained in the form of Pareto front includes all equally good trade-off solutions. But I was wondering, whether these solutions are global optima or local optima or mix of both. In other words, does an evolutionary algorithm like NSGA-II guaranties global optimum solutions?
Thank you in anticipation.
Relevant answer
Answer
No, a Pareto front produced by an evolutionary algorithm does not necessarily include both global and local optima. The Pareto front represents the set of non-dominated solutions in multi-objective optimization problems. These solutions are not dominated by any other solution in terms of all the objective functions simultaneously.
In a multi-objective optimization problem, there can be multiple optimal solutions, known as Pareto optimal solutions, that represent trade-offs between conflicting objectives. These solutions lie on the Pareto front and are considered efficient solutions because improving one objective would require sacrificing performance in another objective.
The Pareto front typically contains a mixture of global and local optima. Global optima are solutions that provide the best performance across all objectives in the entire search space. Local optima, on the other hand, are solutions that are optimal within a specific region of the search space but may not be globally optimal.
The evolutionary algorithm aims to explore the search space and find a diverse set of Pareto optimal solutions across the entire front, which may include both global and local optima. However, the algorithm's ability to discover global optima depends on its exploration and exploitation capabilities, the problem complexity, and the specific settings and parameters of the algorithm.
It's important to note that the distribution and representation of global and local optima on the Pareto front can vary depending on the problem and algorithm used. Analyzing the Pareto front and its solutions can provide valuable insights into the trade-offs and optimal solutions available in multi-objective optimization problems.
  • asked a question related to Optimization
Question
3 answers
What are the best practices for optimizing performance and efficiency in R programming, particularly when dealing with large datasets or computationally intensive tasks? Are there any specific techniques or packages that researchers should be aware of?
  • asked a question related to Optimization
Question
2 answers
Hi everyone,
I want to use the Casadi optimization package for my NLMPC controller in Matlab/Simulink.
I read the examples of https://web.casadi.org/ site, but I can't modify them for my problem.
I want to use Casadi for the tacking problem, so I will have a time-varying cost function and I have time-varying constraints as well.
All the examples which I saw aren't included the time-varying cost function or time-varying constraints.
I would be grateful if anyone can help me.
Regards,
Hossein.
Relevant answer
Answer
Thank you so much for your kind response, Dear Mostak.
After some deeper searches, I could find a good example in the Casadi blog which has implemented the Casadi for optimal control of the Vanderpol system. You can catch it up from the following link:
I could modify it for my problem (Nonlinear Model predictive control of a Wheeled Mobile Robot), but the tracking performance is not good as expected from an MPC controller. The tracking performance is sensitive to the cost function weighting factors and based I my knowledge the MPC weighting factors tunning is straightforward and should not be a challenging task.
Maybe I make mistakes in modifying the Simulink source file, but I checked the Simulink file over and over.
Moreover, I tried to convert the simulation file of the following code to the Simulink file and call the Casadi using the s-function, I did it but the simulation results is wrong.
Any positive experience in converting these examples to the Simulink file could help me.
Regards,
Hossein.
  • asked a question related to Optimization
Question
6 answers
Suppose we have a HEN with several multi-pass heat exchangers. However, due to some technical constraints all these exchangers are modelled simply using single pass equations.
What will the impact if such a simplistic model is used in optimization problems, such as network optimization for retrofitting or cleaning scheduling?
For instance, it is clear that we may not end up with global optimal solutions but still what will the qualitative impact of such approximations?
Relevant answer
Answer
To formulate of this model you need to consider the amount of information included in it:
  • asked a question related to Optimization
Question
1 answer
I am using Gaussian to estimate the ionization potential of a cluster of molecules including 6 molecules of Methanol and 1 molecule of Fluorobenzene, I have optimized the geometry of the neutral cluster and then did a single point energy calculation of the optimized geometry with +1 charge, the difference between energy of the two gives me a rough estimate of the IP, my question is how can we interpret this IP, is it the IP of the whole system or the molecule from which the electron has been removed? also by visualizing the HOMO orbitals in both cases I noticed that the HOMO in neutral case is one of the Pi orbitals of the Fluorobenzene ring while in the ionized case it's the bonding orbital of one of the methanol molecules, not sure how to interpret that?
Relevant answer
Answer
I hope you will be fine
I have read your problem, there is two way to find the IP. One is you will perform neutral molecules and visualize the HOMO LUMO energy. A highly occupied orbital shows the maximum energy to donate the electron so HOMO energy is equal to IP similarly LUMO shows maximum energy to accept an electron that is also equal to EA. But in another way, you will perform a neutral molecule and note down the energy of the molecule and again perform that molecule after adding + charge and calculating energy. In the end you can calculate the IP by differentiating energy .
  • asked a question related to Optimization
Question
4 answers
Hi everyone,
I'm performing DFT Calculation / Geometry Optimization of some 5,7-dibromobenzofurane hydrazide derivatives using ORCA 4.2.1 and BY3LP basis set (! B3LYP RIJK def2-TZVP def2/JK).
Each of 5,7-dibromobenzofurane derivatives has two isomers: anti-isomer and syn-isomer.
While the anti-isomer of a compound was successfully calculated with SCF converged after 43 cycles, the syn- one was not able to obtain the final results with this error:
----------------------------------------------------------------------------------
FINAL SINGLE POINT ENERGY -6213.007766579487 (Wavefunction not fully converged!)
----------------------------------------------------------------------------------
ERROR
This wavefunction IS NOT FULLY CONVERGED!
You can't use it for properties or numerical calculations !
Aborting the run ...
Please restart calculation (with larger maxiter/different convergence flags)
----------------------------------------------------------------------------------
Herein I attached two ouput files corresponding two isomers of a compound.
Relevant answer
Answer
Hi,
This answer is purely technical, as I do not know much about your molecule.
You are not performing a geometry optimization. The input file is for a single point calculation.
You need TightOpt or Opt in your keywords.
Also try the RIJCOSX method instead of RIJK (Reasons are mentioned in the ORCA manual)
The B3LYP has its own problems (difficulty in convergence being the most prominent one).
I would also change the %maxcore to a reasonably high value.
I believe you can also check the GRID options given in the manual.
Please note that GRID options are different in ORCA 4 and ORCA 5
On that note:
For optimization I would use the following
! B3LYP def2-TZVP RIJCOSX def2/J TightOPT KDIIS
If this does not work try
=============================================
! BP86 def2-TZVP RIJCOSX def2/J TightOPT KDIIS
I would then perform a Single Point calculation for the geometry obtained from the above method.
For single point replace BP86 with B3LYP or any other fucntional that is suitable for your system, and remove the TightOPT keyword.
=============================================
You should also add dispersion related keyword to account for dispersion corrections.
In that case I would use
! B3LYP def2-TZVP RIJCOSX def2/J TightOPT KDIIS D3BJ
or
! BP86 def2-TZVP RIJCOSX def2/J TightOPT KDIIS D3BJ
Hope this helps.
Good luck,
Sachin
  • asked a question related to Optimization
Question
3 answers
I am having issues resolving PCR inhibition in rhino dung samples for a metagenome sequencing project. I used the DNeasy Blood and Tissue Kit to extract gDNA (with expected low yields, but DNA present all the same), and have attempted to clean extracts amplify the 18S region using NEB's Q5 HiFi 2x Mastermix. I know that the primers themselves are robust, the positive control looks great, and all fecal samples EXCEPT for rhino amplify well! Cleanups/Optimizations that I have tried: 1) Monarch Kit (best Nanodrop 260/230, 260/280 values), 2) Double extractions using Qiagen's DNeasy columns, 3) Dilutions (1:5, 1:10, 1:20, 1:50, 1:75), 4) Optimizing PCR by adding 5% DMSO and 5M Betaine, 5) Zymo's 1-Step PCR Inhibitor Cleanup Kit.
Help!
Relevant answer
Answer
PCR inhibition can be a common issue in fecal samples, especially in wildlife fecal samples, due to the presence of various inhibitors that can co-purify with the DNA during extraction. It seems that you have already tried several approaches to resolve the issue, but still facing the problem.
Here are some additional suggestions that may help you to address the PCR inhibition in your rhino dung samples:
  1. Try using different DNA extraction kits: Different extraction kits may have different efficiencies for removing inhibitors from fecal samples. You can try using different kits and compare their performance.
  2. Dilute the extracted DNA: In some cases, the concentration of inhibitors may be high enough to affect PCR amplification. Diluting the extracted DNA may reduce the concentration of inhibitors and help to overcome PCR inhibition.
  3. Use PCR enhancers: Certain chemicals, such as bovine serum albumin (BSA) or trehalose, can act as PCR enhancers and help to mitigate the effects of inhibitors. You can try adding them to your PCR reaction to see if it helps.
  4. Increase the annealing temperature of the PCR: Sometimes, inhibitors can affect the specificity of the PCR reaction by interfering with primer annealing. Increasing the annealing temperature of the PCR may help to overcome this issue.
  5. Use nested PCR: Nested PCR involves using two sets of primers to amplify the target region in two separate PCR reactions. The first reaction uses external primers to generate a larger product, and the second reaction uses internal primers to amplify a smaller product nested within the first product. This approach can help to reduce the effects of inhibitors by diluting them over two PCR reactions.
  6. Use a different DNA polymerase: Some DNA polymerases are less susceptible to the effects of inhibitors than others. You can try using a different DNA polymerase to see if it helps to overcome PCR inhibition in your rhino dung samples.
These video playlists might be helpful to you:
  • asked a question related to Optimization
Question
1 answer
Could anyone please mention the inputs i require from an offgrid wind farm for the optimization of LCOH.
I am really new into this topic and currently doing research on the modelling aspect.
Relevant answer
Answer
perhaps something like equations B.24, B25 and B.26 and the predecessors-equations in ... http://dx.doi.org/10.1016/j.apenergy.2021.117481 ... might provide some initial help (same one here: )
  • asked a question related to Optimization
Question
2 answers
I have optimized several of my diastereomers on spartan (M06-2X, 311+G**, CPCM ACETONITRILE) I managed to have all positive frequencies. However I'm getting the syn isomer as the more favorable, however, my experimental data clearly indicates that the anti is the more favorable product. Can anyone suggest to me what to do? I have tried other methods and the results are the same.
Relevant answer
Answer
Thank you Michal. I will try right now your suggestions. I have invested a lot of time in this. I am working with an organic molecule furan type medium size 350 gr/mol. I just need the optimized geometry of the 2 isomers and compare the energy difference. The energy difference usually is between 0.5 to 1 Kcal/mol always favoring the syn isomer. in another case, I got a 6 kcal difference. My experimental data is clear and it is indeed the anti isomer the major product.
  • asked a question related to Optimization
Question
5 answers
Optimization is a statistical technique and done by using linear programming. it is being used in farming systems.
Relevant answer
Answer
Dear Reza
In your point 1, not everything is profit or cost. You can minimize water consumption as well of fertilizers or maximize land use.
In your point 4 you should say 'mathematical inequations' not 'equations'.
This is where the strength of LP lies
  • asked a question related to Optimization
Question
4 answers
Although I have tried certain methods to remove the error.But it still persists.
I have cleaned the disk, restart the system and use the system best suited to satisfy the computational requirements.
In addition, I also try installing it again in the system.
But still error persist.
This was suggexted by someone.
Relevant answer
Answer
Sure Sir ....
I will look into them and will let you know.
Thank you
  • asked a question related to Optimization
Question
4 answers
Hello experts
This question is shared with one of my research team.
We are dealing with an optimization problem in which the algorithm will choose the cross-section of the column (RC structure) between a lower and an upper bound (e.g., LB and UB).
We know that the obtained optimal values for the section can be for example 330mm.
Recently, we came across this phrase in a paper dealing with the same problem where the author stated that 'The column sections are square with dimensions of 250 mm × 250 mm to 1200 mm × 1200 mm, by a step of 50 mm'
Our concern is how to oblige the algorithm to choose 50mm for the next candidate within the design interval.
Anyone knows how to do it, please?
Relevant answer
Answer
To ensure that the optimization algorithm chooses a step size of 50mm within the design interval, you can incorporate a discretization constraint into the optimization problem. This constraint will restrict the possible values for the cross-section to a finite set of discrete values, with a fixed step size of 50mm.
One way to implement this constraint is to introduce a binary variable for each possible cross-section dimension, where the variable takes the value of 1 if that dimension is selected and 0 otherwise. Then, you can use a set of linear constraints to ensure that only one dimension is selected, and the selected dimension is a multiple of 50mm within the given design interval.
For example, if the design interval is [250mm, 1200mm], you can define the binary variable x_i for each possible dimension d_i within this interval, where d_i = 250mm + 50mm * (i-1) for i = 1, 2, ..., 19. Then, you can add the following set of constraints to the optimization problem:
  • Only one dimension can be selected: Sum(x_i) = 1
  • The selected dimension is within the design interval: Sum(d_i * x_i) >= LB and Sum(d_i * x_i) <= UB
  • The selected dimension is a multiple of 50mm: d_i * x_i = k * 50mm for some integer k
These constraints will ensure that the algorithm chooses a cross-section dimension within the given design interval, with a step size of 50mm, and only one dimension is selected. By adding this discretization constraint to the optimization problem, you can ensure that the algorithm will always choose the next candidate within the design interval with a step size of 50mm.
  • asked a question related to Optimization
Question
3 answers
Where is the Jade due to the throwing out of a brick and a paving stone?
A brand new conception of preferable probability and its evaluation were created, the book was entitled "Probability - based multi - objective optimization for material selection", and published by Springer, which opens a new way for multi-objective orthogonal experimental design, uniform experimental design, respose surface design, and robust design, discretization treatment and sequential optimization, etc.
It aims to provide a rational approch without personal or other subjective coefficients, which is available at https://link.springer.com/book/9789811933509,
DOI: 10.1007/978-981-19-3351-6.
Best regards.
Yours
M. Zheng
  • asked a question related to Optimization
Question
5 answers
What challenges and use cases are associated with designing an optimization xApp for O-RAN?
In O-RAN (Open RAN), xApp communicates with RIC (Radio Intelligence Controller) to impose policies on the radio access network (RAN). The RIC is responsible for managing and coordinating the DUs (Distributed Units) and RUs (Radio Units) in the RAN. The workflow for this process is as follows:
  1. xApp generates and sends a policy to the RIC.
  2. The RIC receives the policy and translates it into a series of commands.
  3. The RIC sends the commands to the relevant DUs and RUs.
  4. The DUs and RUs execute the commands and update their configurations accordingly.
  5. The RIC monitors the status of the DUs and RUs and reports back to the xApp.
  6. The xApp has access to the status of the DUs and RUs and can make updates to the policies based on the received status.
In this way, xApp has access to both DU and RU activities through the RIC. The RIC acts as an intermediary between xApp and the DUs and RUs, ensuring that policies are applied consistently and effectively across the RAN.
The Question is How can we read and check the xApp activities? its inside the RIC or logged in CU DU?
Relevant answer
Esmaeil Amiri Many Thanks
  • asked a question related to Optimization
Question
1 answer
Can anybody help me if in finding any existing literature where I can find the energy of Polyethylene optimized structure 12 monomer units using DFT level of theory
Relevant answer
Answer
I think this is a very specific system to be found in the literature. However, since it is not a huge system, I recommend you to calculate by yourself (at DFT level it will not take so long)
Best,
Fernando
  • asked a question related to Optimization
Question
2 answers
HCP has two parameters to optimize namely a and c/a; the process detailed here gives pretty accurate result to determine those parameters. Zr is taken as an example here, where positions are special, high symmetry positions, i.e. (1/3, 2/3,1/4) and (2/3, 1/3,3/4)
i. Take 7 to 8 different volumes across the estimated equilibrium volume (from published XRD data).
ii. Range of volume scanned should be typically within +/- 10%
iii. If atom positions are in high symmetry positions then atoms should not be moved. However, in the POSCAR file set 'selected dynamics' and motion should be set to T, to get force info in OUTCAR, but set ISIF=5 in INCAR to change only the shape of the unit cell.
An example of POSCAR -
HCP Zr parama (vary this to get different volume) 1.000000000 0.000000000 0.00000000000 -0.500000000 0.866025404 0.00000000000 0.000000000 0.000000000 1.60000000000 Zr 2 Selective dynamics Direct 0.6666666666666667 0.3333333333333333 0.7500000000000000 T T T 0.3333333333333333 0.6666666666666667 0.2500000000000000 T T T
iv. INCAR setting
ISTART=0 LREAL=.FALSE. PREC=Accurate ADDGRID=.TRUE. ENCUT=550 ISPIN=2 NPAR=6 MAGMOM=2*2.0
IBRION=2 ISIF=4 POTIM=0.15 ISMEAR=1 SIGMA=0.01
NSW=100 NELM=50 EDIFF=1.0E-6
v. Fit 3rd order BM EOS to determine the equilibrium energy, volume and bulk modulus (E0, V0 and B)
vi. For each run also find the final a and c/a
vii. Fit 3rd order BM EOS between E vs. a^3 to determine the equilibrium a0^3, during this fitting keep E0 constant (found from step v)
viii. Now we have both V0 and a0, from which c0/a0 can be calculated. Use these final cell parameters to determine the energy accurately using ISMEAR = -5 in INCAR.
Relevant answer
Answer
**** Modified version ****
HCP has two parameters to optimize namely a and c/a; the process detailed here gives pretty accurate result to determine those parameters.
i. Take 7 to 8 different volumes across the estimated equilibrium volume (from published XRD data) using ISMEAR = 0 or 1
ii. Range of volume scanned should be typically within +/- 10%
iii. If atom positions are in high symmetry positions then atoms should not be moved; accordingly, use ISIF = 4 or 5
v. Fit 3rd order BM EOS to determine the equilibrium energy, volume and bulk modulus (E0, V0 and B), the useful quantity from this fitting is V0 and B
vi. With this fixed V0 run again with ISIF=4 or 5 to determine a0 and c0
vii. Keeping this a0 and c0 fixed (i.e. fixed V0 ) take another run using ISMEAR=-5 for accurate ground state energy (E0) calculation
  • asked a question related to Optimization
Question
4 answers
In consideration of lipemic samples being one of the most commonly encountered interferences in routine clinical chemistry assays (Ho et al., 2021, p. 1), are there any removal methods that are immediately available for samples affected with lipemia?
According to Nikolac (2014), the CLSI recommended method is ultracentrifugation among other methods, however, this method may be quite costly. So, I’m wondering if there are methods which would be more accessible for small, remote laboratories.
Reference Articles:
  • Ho, C. K., Chen, C., Setoh, J. W., Yap, W. W., & Hawkins, R. C. (2021). Optimization of hemolysis, icterus and lipemia interference thresholds for 35 clinical chemistry assays. Practical Laboratory Medicine, 25, e00232. https://doi.org/10.1016/j.plabm.2021.e00232
  • Nikolac N. (2014). Lipemia: causes, interference mechanisms, detection and management. Biochemia medica, 24(1), 57–67. https://doi.org/10.11613/BM.2014.008
Relevant answer
In addition to ultracentrifugation, Soleimani, Mohammadzadeh, and Asadian (2020) suggest the following additional elimination techniques: lipid extraction; sample dilution; and serum blank. They have suggested using serum blanks for samples that will be utilized to measure glucose, GGT, creatinine, albumin, CPK, and amylase as serum blanks eliminate the need for ultracentrifugation in cases of low degrees of lipemia.
For laboratories encountering cases of lipemia, specifically in the moderate to severe lipemic levels, ultracentrifugation is still the optimum removal technique for lipemic samples used for assessment of calcium, magnesium, phosphorus, total protein, iron, TIBC, urea, and chloride.
Reference:
  • Soleimani, N., Mohammadzadeh, S., & Asadian, F. (2020). Lipemia interferences in biochemical tests, investigating the efficacy of different removal methods in comparison with ultracentrifugation as the gold standard. Retrieved from Journal of Analytical Methods in Chemistry, 2020, 1-6. https://doi.org/10.1155/2020/9857636
  • asked a question related to Optimization
Question
3 answers
Interpretable, credible and responsible multimodal artificial intelligence preface--DIKWP model (beyond ChatGPT)
Already 312 times read 2023-2-11 15:23 |System Classification: Paper Exchange
First answer what is artificial intelligence (Artificial Intelligence, AI)?
Subjects and objects in the entire digital world and cognitive world can be consistently mapped to the five components of the DIKWP model and their transformations: Data Graph, Information Graph, Knowledge Graph, Wisdom Map (Wisdom Graph), intention map (Purpose Graph).
Each DIKWP component corresponds to the semantic level of cognition, the concept and concept instance level of human language: {semantic level, {concept, instance}}
Model <DIKWP Graphs>
::=(DIKWP Graphs)*(Semantics, {Concept, Instance})
::={ DIKWP Graphs*Semantics, DIKWP Graphs*Concept, DIKWP Graphs*Instance }
::={ DIKWP Semanics Graphs, DIKWP Concept Graphs, DIKWP Instance Graphs }
Interactive scene <DIKWP Graphs>
::={DIKWP Content Graph includes: Data Content Graph, Information Content Graph, Knowledge Content Graph, Wisdom Content Graph, Purpose Content Graph;
DIKWP cognitive model (DIKWP Cognition Graph) includes: Data Cognition Graph, Information Cognition Graph, Knowledge Cognition Graph, Wisdom Cognition Graph , Purpose Cognition Graph.
}
Artificial intelligence is the capability part of DIKWP interaction.
AI::=(DIKWP Graphs)*(DIKWP Graphs)*
Narrow definition: Artificial intelligence is the development-oriented elimination of duplication in the DIKWP interaction, the integrated storage-computing-transmission iterative capability and the cross-DIKWP-oriented (Open World Assumption) OWA scope conversion capability.
We are conducting ChatGPT's artificial intelligence ability test and look forward to sharing it with you.
Examples of our related work:
Typed Resource-Oriented Typed Resource-Based Resource Management System (Authorized)
  Value Driven Storage and Computing Collaborative Optimization System for Typed Resources
   Application publication number: CN107734000A
For a list of all relevant invention patents, see:
List of Chinese national invention patents authorized by the DIKWP team for the first inventor Duan Yucong during the three years from 2019 to 2022 (69/241 in total)
Relevant answer
Answer
Hi,
Simply put, AI, which stands for "artificial intelligence," refers to systems or machines that mimic human intelligence to perform tasks and can iteratively improve based on the information they gather. Artificial intelligence manifests itself in many forms.
  • Les assistants intelligents utilisent l’IA pour analyser les informations critiques à partir de grands ensembles de données en texte libre afin d’améliorer la planification.
  • Chatbots use AI to understand customer problems faster and respond more effectively.
  • Recommendation engines can automatically suggest TV shows based on viewers' habits.
Best regards
  • asked a question related to Optimization
Question
3 answers
Hello dear researchers.
Please, how do I know that I have done a good optimization of the structure (I use abinit), should I see something in the output file or just compare the cell parameters with the experimental values?
Thank you in advance.
Sincerely.
Relevant answer
Answer
Hello,
There are some important tutoriel in the website of Abinit, see this link:
  • asked a question related to Optimization
Question
4 answers
Hello! I am going to conduct a study on the application of Vehicle Routing Problem in real world. However, I am struggling with how I construct my networks. I would like to ask on how to define the edges/arcs/links between the vertices.
For example, what should the edge between cityA and cityB represent? Most literatures use travel times which is based on road distances from cityA to cityB. However, there are a lot of paths from cityA to cityB. The way to address this is to use the shortest path from cityA to city B. Are there any alternatives to address this issue? What should the edge between two vertices represent?
Relevant answer
Answer
You can use the real distance or travel time of the best path that link each pair of cities. Usually, travel times are calculated based on the real distance and an assumed vehicle average velocity.
You always need to calculate the Cost-Matrix between all the cities (nodes) as instance data. To make this possible recommend OSRM or Vallhalla or any proprietary solution like ArcGIS Desktop Network Analyst
  • asked a question related to Optimization
Question
5 answers
This new way of accessing information through a reward model for reinforcement learning requires collecting comparison data, which consists of two or more model responses classified by quality. Data collection is performed through conversations that the AI trainers had with the chatbot, enhanced by Reinforcement Learning with Human Feedback. A written message is randomly selected per model, trying out several alternative conclusions and asking the AI trainers to rate them.
The use of reward models can adjust the model using Proximal Policy Optimization. Models such as GPT-3 and Codex are also implemented.
Relevant answer
Answer
António Brandão ChatGPT, as a big language model, has the potential to transform the way we engage with the Internet in several ways:
1. Personalization: ChatGPT may be trained to recognize the context of a discussion and answer in a tailored manner, giving the user with more accurate and relevant information.
2. Speed: Using language models such as GPT-3 and Codex, ChatGPT can swiftly interpret and react to user questions, making information access faster and more efficient.
3. Interactivity: ChatGPT may be linked to a variety of platforms, including websites and applications, to give users an interactive experience. This can make information access more interesting and user-friendly.
4. Improved performance: By combining reward models and reinforcement learning with human input, ChatGPT's performance can be constantly improved, making it more accurate and dependable over time.
5. Better outcomes: Using Proximal Policy Optimization, the model may adjust itself to the feedback supplied by human trainers, resulting in better results for end users.
The combination of these qualities can improve the user experience by making information access over the Internet more customized, rapid, interactive, and accurate.
  • asked a question related to Optimization
Question
6 answers
How can I calculate ANOVA table for the quadratic model by Python?
I want to calculathe a table like the one I uploaded in the image.
Relevant answer
Answer
To calculate an ANOVA (Analysis of Variance) table for a quadratic model in Python, you can use the statsmodels library. Here is an example of how you can do this:
#################################
import statsmodels.api as sm
# Fit the quadratic model using OLS (Ordinary Least Squares)
model = sm.OLS.from_formula('y ~ x + np.power(x, 2)', data=df)
results = model.fit()
# Print the ANOVA table
print(sm.stats.anova_lm(results, typ=2))
#################################
In this example, df is a Pandas DataFrame that contains the variables y and x. The formula 'y ~ x + np.power(x, 2)' specifies that y is the dependent variable and x and x^2 are the independent variables. The from_formula() method is used to fit the model using OLS. The fit() method is then used to estimate the model parameters.
The anova_lm() function is used to calculate the ANOVA table for the model. The typ parameter specifies the type of ANOVA table to compute, with typ=2 corresponding to a Type II ANOVA table.
This code will print the ANOVA table to the console, with columns for the source of variance, degrees of freedom, sum of squares, mean squares, and F-statistic. You can also access the individual elements of the ANOVA table using the results object, for example:
#################################
# Print the F-statistic and p-value
print(results.fvalue)
print(results.f_pvalue)
#################################
I hope that helps
  • asked a question related to Optimization
Question
4 answers
For difficult to transduce adherent cell lines, I was wondering if anybody has tried spinoculation with polybrene? If so, what is the protocol you used?
Relevant answer
Answer
Susan C Hubchak Hi Susan, thank you for your response. Have you tried spinning any adherent cells with polybrene before? If so, what was the recommended time of spinning and conditions?
  • asked a question related to Optimization
Question
3 answers
Please advise a reference to paper/book/sources with description of Complex value test functions for optimization like extended Rosenbrock or Powell? There are many analytical functions for testing non-linear/optimization algorithms but I was able to find only cases for real numbers. So the question is how to test a case when Jacobian/residual are complex value matrix/vector?
Relevant answer
Answer
You can look into the following Book:
Complex Valued Matrix Derivatives : With applications in Signal processing and Communication, by Are Hjorungnes.
  • asked a question related to Optimization
Question
5 answers
linear least squares problem::
fit f(t) = sin(t) on the interval [0, π] with polynomials of degree n with n = 1, 2, 3, · · · , 10. Here, we use equally spaced nodes.
Solve the normal equation with a backslash in Matlab. Save the norm of the residual and the condition numbers of AT A??
Could anybody please tell me how can find x, y, and A in that case ??
Relevant answer
Answer
The question seems incorrect. We needn't find x and y.
We have {(xi, yi = sin(xi))}, i=1,...,N and seek (a_n, ..., a_0) for a polynomial function
f(x) = a_n * x^n + ... + a_0.
Least Square minimization gives
A=
( Sum(xi^n) Sum(xi^(n-1)) ... Sum(xi^0);
Sum(xi^(n+1)) Sum(xi^(n-2)) ... Sum(xi^1);
.............................................
Sum(xi^(2*n)) Sum(xi^(2*n-1)) ... Sum(xi^n);
);
b = (Sum(yi); Sum(xi*yi);); ... Sum(xi^n*yi) );
At last,
(a_n a_(n-1) ... a_0) = A^(-1)*b
  • asked a question related to Optimization
Question
6 answers
Hello, I've been tasked with validating a 2kb region of DNA. A colleague designed primers with the F melting at 53.8 and the reverse at 59.7. I believe they used 54C which had multiple bands show up in their gel due to specificity issues. I am trying to optimize the reaction but don't know what temp would give the best results. Redesigning was my first thought but that's not an option. My plan now is to start at 56, see what I get if its still not specific enough than increase until I get clear bands. The problem however is this will be quite time consuming and will waste resources. Any input on next steps would be greatly appreciated.
Thank you
Relevant answer
Answer
I agree with John Hildyard
However, you have one more option. Your PCR machine should have an option for gradient setup. So why not try a gradient PCR and find out the optimum Tm for the available primer pair? It works most of the time.
Hope this helps!
Best!
  • asked a question related to Optimization
Question
3 answers
I am working on topology optimization for photonic devices. I need to apply a custom spatial filter on the designed geometry to make it fabricable with the CMOS process. I know there exist spatial filters to remove the pixel-by-pixel and small features from the geometry. However, I have not seen any custom analytical or numerical filters in the literature. Can anyone suggest a reference to help me through this?
Thanks,
Relevant answer
Answer
Many thanks for your reply.
The list of papers you've provided perfectly developed the concept, particularly the tutorial paper that goes through the optimization problem step by step.
  • asked a question related to Optimization
Question
1 answer
Hello Researchers,
I am Marwen Amiri, A PhD student, my subject is "Optimization of RFID systems used in wireless body networks" it is a purely "internet of things" subject, I wanted to know if it would be possible to simulate WBAN networks with the physiological parameters of a human body using NetSim or Omnet ++ or another simulator ? i want to modify the TxPower and the distance between sensors to evaluate the performance of a WBAN network in terms of PLR, latency and energy consumption. The main objective is to determine some objectives of optimization by simulation and testing of some algorithms of multiobjective optimization (Node coverage, interference, control of Txpower, number of sinks, number of nodes, etc...)
if it's possible, I wanted to know also, how can I find the library of a Phantom of a human body with its physiological parameters to use it in one of the iot simulators. In fact, I found several simulations of BAN networks on Youtube, but without source code, since we want to work on a human body with physiological parameters to perform our simulations with normal or RFID sensor nodes.
Can you help me with information, papers or contacts ? I did not find many resources in this area of ​​research
Cordially
Relevant answer
Answer
The CSV / XL file has readings of from 11 different sensors measuring physiological parameters such ECG, EEG, Airflow, …, etc.
  • asked a question related to Optimization
Question
4 answers
There are various steps involved in western blot analysis. Any tips or optimization tricks you might have used that worked and made work easy for you. Please kindly, drop in in the discussion. For new and Old Grad students that are working with old equipments and not able to afford already- made reagents. Thanks
Relevant answer
Answer
Thank you. Your contribution is greatly appreciated. I know this will help a student someday.
  • asked a question related to Optimization
Question
7 answers
In his name is the judge
Hi
There is a fuzzy logic control system in python. The system contain 2 inouts and 18 outputs.
inference of system is mamdani and shape function used to be guassian.
Then in term of refine performance of the controller I need to optimize specifications belong to shape functions of both input and output. In order to that I need to use multi objective optimization.
We have 2 input and 1 output in case of this problem. I have developed 3 shape functions for each entrance and 3 for output and the shape function is gaussian so we have 18 parameters totally.
I defined my problem as a function in python. But notice this I there is not any clear relationship between input and output of function. It’s just a function which is so complicated with 2 inputs and 18 outputs.
I made my decision to use NSGAII algorithm and I really don't want to change the algorithm.
So I try every way to optimize my function but I didn’t find any success. By searching about python library which can do multiobjective optimization I find Pymoo as the best solution but I really failed to optimize my function which is complicated custom function, with it.
So It’s really my pleasure if you can introduce me a library in python or suggest me a way that I can use Pymoo in order to this aim.
wish you best
Take refuge in the right.
Relevant answer
Answer
You can stick with Mamdani Fuzzy System if it is comfortable for you to design a "workable" FIS. You probably don't need optimization if your FIS works satisfactorily. From the "workable" FIS to the "satisfactory" FIS, you probably just need make minor adjustment to the design parameters. That's the Spirit of Engineering Design.
  • asked a question related to Optimization
Question
2 answers
I am trying to optimize zeolite bulk structure with some of the silicon atoms being replaced by Al in VASP. But it's not converging and the job stops after 1 iteration. There is no error message also. I am using vdw-RE tag. What should I do to converge it successfully?
Relevant answer
Answer
Sure, I am attaching INCAR and the POSCAR files below.
  • asked a question related to Optimization
Question
1 answer
I have L16 for Machining and some researchers do RSM after GRA using GRG data.
How we can do that?
Thanks
Relevant answer
Answer
@Asim You can do GRA irrespective of RSM or L16 Taguchi. GRA is applied where you have multiple responses and if you need to find out the optimal responses
  • asked a question related to Optimization
Question
9 answers
When I try to perform the following calculation, Python gives the wrong answer.
2*(1.1-0.2)/(2-0.2)-1
I have attached a photo of the answer.
Relevant answer
Answer
Mathematically, the answer to the equation is zero; the answer Python spat out is pretty much as close as you can get to the representation of zero with a typical computer.
This is a classic floating point problem: https://en.wikipedia.org/wiki/Floating-point_error_mitigation
  • asked a question related to Optimization
Question
10 answers
I am working on a non-linear optimization problem. Even though I wrote the code correctly and it doesn't give an error message, the optimal values are zero. please if there is someone who masters in lingo model help me .
Thank you
Relevant answer
Answer
Dear Sima
Thank you for sending me your material
As I told you I don't know LINGO. I work with Solver in Excel.
As a first difference LINGO puts alternatives in rows and criteia in columns, which is exacly opposite as Solver, but of course, it does not influence in the result.
Inspecting your matrix, I notice that are many symbols that you dont say what they mean. For instance
Pi, Yj,Pw, W, Pin
Of course, the sum of performance values for un criterion should be ≤ since you arf maximizying.
An issue that called immediately my attention is the large value for 📷
It appears that there is a contradiction here, because in your first column you establish
📷
📷
The same for the other columns
That is, in one inequation the sum of all performance values in column 1, should be less or equal to 6750, and in the other inequation you say that the weighted sum should be less or equal to 56850000.
Unfortunately, I don’t know the meaning of W, which I guess are weights (although you don’t need weights in LP), but it seems that it must comply simultaneously with two very different values. If it is ≤ 6750, I don’t see how it could be less than 56850000.
Obviously, the result is zero because this is not feasible.
I don’t understand the expression of your objective function. Pls. explain
It would help if I could k now the meaning of each criterion.
I hope it helps
  • asked a question related to Optimization
Question
2 answers
I'm searching for new collaborations. I'm focused mostly on numerics on obtaining solitons bifurcating from band edges and localized modes. I'm specialized in shooting methods with more than one parameter, NR optimized for CUDA obtaining solutions, parametric curve step to obtain branches that cannot be described by a function. Optimization of split-step FFT dynamics with coupled Nonlinear partial differential equations, Ex: SHG was the harder one. I worked previously with V. Konotop, F. Abdullaev and B. Malomed. I was first author on all papers. They provided the equations and researched on obtaining solutions.
  • asked a question related to Optimization
Question
9 answers
Although the genetic algorithm is very helpful to find a good solution, it is very time-consuming. I've recently read an article in which the authors used the genetic algorithm for pruning a neural network on a very small dataset. They pruned a third of their network and reduces the size of the model from 90MG to 60MG. Their pruning also decreased the inference time of their model by around 0.5 seconds. Although, unlike other methods, pruning using the genetic algorithm does not deteriorate their model's performance, finding redundant parts of the network using the genetic algorithm is an overhead. I wonder why they think their method is useful and why people still use the genetic algorithm.
Relevant answer
Answer
Genetic algorithms have the several characteristics over others such as , (1) Natural selection and natural genetics are at the heart of the Genetic Algorithm. -(2)These are simple to comprehend and use. -(3) These are frequently encountered in optimization issues. (4)These are based on a population of points rather than a single point. -(5) Instead of deterministic rules, these utilize probabilistic transition rules. -(6)Genetic algorithms can handle a large number of variables efficiently. - (7)No derivative information is required for these methods. -(8)These are more successful when dealing with complicated difficulties than when dealing with basic problems.
  • asked a question related to Optimization
Question
4 answers
I have trained a regression svm model for a set of experimental data which has 4 parameters - initial concentration, pH, T and dosage. The response is equilibrium loading. Now, I want to use the trained model to get optimal conditions for the same, i.e., to find the experimental parameters at which we get maximum equilibrium loading. Since, a svm model doesn't give the parameters of the model it would be difficult to find the parameters. Kindly suggest some ways to do this.
Relevant answer
Answer
  • asked a question related to Optimization
Question
3 answers
Dear friends,
Would you please tell me where I can find a dynamic list (updated constantly) of new meta-heuristic algorithms?
Thanks in advance for your guidance,
Reza
Relevant answer
Answer
For a humorous treatment, see the "bestiary":
  • asked a question related to Optimization
Question
3 answers
I am looking for examples of using home energy storage to reduce energy peaks on a daily basis in the case of PV. There is a need to use many home energy storage (several hundred thousand in Poland) to cut PV energy peaks.
Relevant answer
Answer
  • asked a question related to Optimization
Question
2 answers
In robust optimization, random variables are modeled as uncertain parameters belonging to a convex uncertainty set and the decision-maker protects the system against the worst case within that set.
In the context of nonlinear multi-stage max-min robust optimization problems:
What are the best robustness models such as Strict robustness, Cardinality constrained robustness, Adjustable robustness, Light robustness, Regret robustness, and Recoverable robustness?
How to solve max-min robust optimization problems without linearization/approximations efficiently? Algorithms?
How to approach nested robust optimization problems?
For example, the problem can be security-constrained AC optimal power flow.
Relevant answer
Answer
To tractably reformulate robust nonlinear constraints, you can use the Fenchel duality scheme proposed by Ben Tal, Hertog and Vial in
"Deriving Robust Counterparts of Nonlinear Uncertain Inequalities"
Also, you can use Affine Decision Rules to deal with the multi-stage decision making structure. Check for example: "Optimality of Affine Policies in Multistage Robust Optimization" by Bertsimas, Iancu and Parrilo.
  • asked a question related to Optimization
Question
3 answers
In his name is the judge
Hi
I want to learn multi-objective optimization with NSGAII in python for my research.
Please recommend a good source for learning NSGAII in python.
wish you best
Take refuge in the right.
Relevant answer
Answer
thank you for your suggestion.
  • asked a question related to Optimization
Question
8 answers
How does one optimize a set of data which is comprised of 3 input variables and 1 output variable (numerical variables) using a Genetic Algorithm? and also how can I create a fitness function? How is a population selected in this form of data? What will the GA result look like, will it be in a form of 3 inputs and 1 output?
I do understand how the GA works, however, I am confused about how to execute it with the form of data that I have.
My data is structured as follows, just for better understanding:
3 columns of Input data, and the fourth column of Output Data. (4 Columns and 31 rows) data. The 3 input variables are used to predict the fourth variable. I want to use GA to improve the prediction results.
Lastly, Can I use decimal numbers (E.g. 0.23 or 24.45); or I should always use whole numbers for chromosomes.
Relevant answer
Answer
Decide first whether you want to improve the features or parameters of an algorithm or both? When designing your chromosome in terms of features You must first create a population of candidates that you can do randomly .... On some chromosomes you may want to turn off some features or on some features you can use 1 or 0 for this. Zero to indicate an added feature and to exclude a feature from a given set. In the case of parameters, the value of the chromosome can be a decimal point in the given range.
  • asked a question related to Optimization
Question
2 answers
I have running GA optimization using "gamultiobj" in Matlab. The upper bound and lower bound of my design variables are like [10 30 175 1] and [30 60 225 3]. But after convergence, I see the design variables (like all of them) near 20,47,175 and 1. I am not getting a Pareto Front. What could be the possible reasons for that?
Relevant answer
Answer
Can you please elaborate on your objective functions?
  • asked a question related to Optimization
Question
2 answers
Hello everyone, I am looking for a good MPC quadratic optimization mathematical model to optimize a cost function or performance index, for a battery energy storage state space model. Would anybody suggest a good research paper or post a formulation that contains a good mathematical model for quadratic optimization? An objective function with viable constraints, which can be possible to implement in function solvers such as quadprog or cplex would be ideal. Thank you
Relevant answer
Answer
article :
Suboptimal explicit MPC via approximate multiparametric quadratic programming
bonne courage
  • asked a question related to Optimization
Question
3 answers
In your opinion, what are the main aspects of Econo-Mathematical Optimization ?
Relevant answer
Answer
More details please... single variable, multi-variate, linear, nonlinear, constrained, unconstrained, etc.
  • asked a question related to Optimization
Question
3 answers
I've been using GMAT in my free time to optimize trajectories, and have varied burn component values and spacecraft states, usually with success. The vary command in GMAT, with the Yukon optimizer that I am using, has the following parameters that can be changed:
  • Initial value: The initial guess. I know the gradient descent optimization method that GMAT uses is very sensitive to initial conditions and so this must be feasible or reasonably close.
  • Perturbation: The step size used to calculate the finite difference derivative.
  • Max step: The maximum allowed change in the control variable during a single iteration of the solver.
  • Additive scale factor: Number used to nondimensionalize the independent variable. This is done with the equation xn = m (xd + a), where xn is the non-dimensional parameter, xd is the dimensional parameter and this parameter is a.
  • Multiplicative scale factor: Same as above, but it's the variable d in the equation.
For the initial value, I can usually see when my chosen value is feasible by observing the solver window or a graphical display of the orbit in different iterations. The max step is the most intuitive of these parameters for me, and by trial and error, observation of the solver window and how sensitive my target variables are to changes in the control variables I can usually get it right and get convergence. It is still partially trial and error though.
However, I do not understand the effect of the other parameters on the optimization. I read a bit about finite difference and nondimensionalization/rescaling, and I think I understand them conceptually, but I still don't understand what values they have to be to get an optimal optimization process.
This is especially a problem now because I have started to vary epochs (TAIModJulian usually) or time intervals (e.g. "travel for x days" and find optimal x, or to find optimal launch windows), and I cannot get the optimizer to vary them properly, even when I use a large step size. The optimizer usually stays close to the initial values, and eventually leads to a non-convergence message.
I have noticed that using large values for the two scale factors sometimes gives me larger step sizes and occasionally what I want, but it's still trial and error. As far as perturbation goes, I do not understand its influence on how the optimization works. Sometimes for extremely small values I get array dimension errors, sometimes for very large values I get similar results to if I'm using too large a max step size, and that's about it. I usually use 1e-5 to 1e-7 and it seems to work most of the time. Unfortunately information on the topic seems sparse, and from what I can tell GMAT's documentation uses different terminology for these concepts than what I can find online.
So I guess my question is two-fold: how to understand the optimization parameters of GMAT and what they should be in different situations, and what should they be when I want GMAT to consider a wide array of possible trajectories with different values of control variables, especially when those control variables are epochs or time intervals? Is there a procedure or automatic method that takes into account the scale of the optimization problem and its sensitivity, and gives an estimate of what the optimization parameters should be?
  • asked a question related to Optimization
Question
6 answers
I have designed the optimization experiment using Box-Behnken approach.
What should I do if any of the factors combination fails, for example because the aggregation occurs.
Should I review whole optimization or is there any method to skip the particular factors combination?
And if I need to review the whole experiment, what method should I use to evaluate boundary factors values? Screening methods I have seen require at least 6 factors to be screened.
Any help is appreciated.
Greetings.
Relevant answer
Answer
If particular factor combinations are leading to "loss of data" because you can not evaluate it, then you can set so-called constraints in your future DOE. As a result, you will work with D- (in screening) or I-Optimal (in optimization) Designs. You need these computer generated designs in your case, because the design is not orthogonal so classical factorial designs are not appropriate.
  • asked a question related to Optimization
Question
6 answers
I have generated 16 variable probability distributions in the form of a 16 dimensional NumPy array in python. How could I determine all the peaks in this function in python or using some software?
Relevant answer
Answer
Thank you all for the clarifications