Why positive semidefinite state penalty matrix in LQR and LQT problems?

Why the state weighing matrix is taken to be positive semidefinite and not positive definite in optimal control problems - like LQR(Linear Quadratic Regulation) and LQR (Linear Quadratic Tracking?

07 August 2018 2,636 3 View

Which sensors are generally costly in Aircraft systems?

Accelerometer or pitch rate sensor Which sensor is more expensive? Can anyone tell or give a suitable paper or document?

10 November 2017 1,738 1 View

Second order linear equations?

Why is it not possible to obtain a continuous open loop control u(t) such that each solution of y''+y=u(t) approaches the origin as t approaches infinity independently of initial conditions? I rea...

05 June 2017 7,855 2 View

Differential algebraic equations?

Why do we go for differential algebraic modelling of dynamical systems when we can solve the problem algebraic equations as constraints to a simple differential equation (the state of art for...

03 April 2017 8,887 5 View

n linearly independent solutions of a nth order differential equation?

How do I prove that a nth order differential equation has n linearly independent solutions?Also, how to prove that there is no possible solution other than those covered by the linear combination...

07 August 2016 4,939 10 View

How softwares and hardwares work?

We all work in an environment where we use computers extensively for carrying out research.But i believe that not many know the actual interactions between the software and hardware,I want know...

31 December 2015 2,643 2 View

How can the gate to source voltage in a nMOSFET can atract electrons from heavily doped n regions when it is vertical ?

The gate to source voltage in a nMOSFET is vertical. Then how can it attract the electrons in the n region because the electric field associated with it is vertical and does not apply to those...

01 February 2015 3,478 6 View

How to start writing a research paper?

I want start a original work on calculus.How should I begin?

31 December 2014 3,746 2 View

Books for control systems

Please suggest best boks for studyibg control systems engineering.

08 September 2014 1,603 9 View

What decides the value of capacitors used in power supply?

What decides the value of capacitor used in power supply? The value is 2200 microfarad. Please also suggest some books for understanding capacitors from the basics.

04 May 2014 371 6 View

error in running a model in Abaqus

Excessive rotation of nodes in node set ErrNodeExcessRotation-Step1

17 August 2021 0 0 View

error in modelling model in Abaqus

Excessive rotation of nodes in node set ErrNodeExcessRotation-Step1

17 August 2021 0 0 View

MGL tools

20 June 2021 0 0 View

what is the simplest definition of ion exchange capacity

What this unit identifies for the ion exchange capacity ca. 0.92 meq. g-1. I am a newcomer in the membrane area. I just started. I highly appreciate your help

08 May 2021 0 0 View

what is the simplest definition of ion exchange capacity

What this unit identifies for the ion exchange capacity ca. 0.92 meq. g-1. I am a newcomer in the membrane area. I just started. I highly appreciate your help

08 May 2021 0 0 View

i have some problem with chtMultiRegionSimpleFoam

--> FOAM FATAL ERROR: Maximum number of iterations exceeded From function Foam::scalar Foam::species::thermo::T(Foam::scalar, Foam::scalar, Foam::scalar, Foam::scalar (Foam::species::thermo::*)(Foam::scalar, Foam::scalar) const, Foam::scalar (Foam::species::thermo::*)(Foam::scalar, Foam::scalar) const, Foam::scalar (Foam::species::thermo::*)(Foam::scalar) const) const [with Thermo = Foam::hConstThermo >; Type = Foam::sensibleEnthalpy; Foam::scalar = double; Foam::species::thermo = Foam::species::thermo >, Foam::sensibleEnthalpy>] in file /home/ubuntu/OpenFOAM/OpenFOAM-4.1/src/thermophysicalModels/specie/lnInclude/thermoI.H at line 66. FOAM aborting #0 Foam::error::printStack(Foam::Ostream&) at ??:? #1 Foam::error::abort() at ??:? #2 Foam::heRhoThermo >, Foam::sensibleEnthalpy> > > >::calculate() at ??:? #3 Foam::heRhoThermo >, Foam::sensibleEnthalpy> > > >::correct() at ??:? #4 ? at ??:? #5 __libc_start_main in "/lib/x86_64-linux-gnu/libc.so.6" #6 ? at ??:?

24 March 2021 0 0 View

Can we classify HV and LV lines based on line length?

I have dataset which shows the length of power lines. I need to classify the lines based on the line length. Is there a rule to classify the High voltage (HV) and low voltage (LV) lines based on...

03 March 2021 4,116 4 View

What's the best way to measure growth rates in House sparrow chicks from day 2 to day 10?

What's the best way to measure growth rates in House sparrow chicks from day 2 to day 10? Since, the growth curve from day 2 to 10 won't be like the "Logistic curve" it might not follow logistic...

03 March 2021 1,401 3 View

How to increase a model accuracy ?

dear community, my model is based feature extraction from non stationary signals using discrete Wavelet Transform and then using statistical features then machine learning classifiers in order to...

03 March 2021 6,994 5 View

What is the production process of CaFe ferroalloys?

I looking for ferro calcium production process

03 March 2021 1,755 4 View