scholarly journals Suboptimal feedback control of TCP flows in computer network using random early discard (RED) mechanism

2005 ◽  
Vol 2005 (5) ◽  
pp. 477-489 ◽  
Author(s):  
N. U. Ahmed ◽  
Cheng Li
Keyword(s):  
Feedback Control ◽  
Dynamic Model ◽  
Computer Network ◽  
Control Laws ◽  
Doubly Stochastic ◽  
Polynomial Type ◽  
Stochastic Point Process ◽  
Proposed Model ◽  
Recursive Search ◽  
Suboptimal Feedback Control

We consider a dynamic model that simulates the interaction of TCP sources with active queue management system (AQM). We propose a modified version of an earlier dynamic model called RED. This is governed by a system of stochastic differential equations driven by a doubly stochastic point process with intensity as the control. The feedback control law proposed observes the router (queue) status and controls the intensity by sending congestion signals (warnings) to the sources for adjustment of their transmission rates. The (feedback) control laws used are of polynomial type (including linear) with adjustable coefficients. They are optimized by use of genetic algorithm (GA) and random recursive search (RRS) technique. The numerical results demonstrate that the proposed model and the method can improve the system performance significantly.

scholarly journals Suboptimal RED Feedback Control for Buffered TCP Flow Dynamics in Computer Network

2007 ◽  
Vol 2007 ◽  
pp. 1-17 ◽  
Author(s):  
N. U. Ahmed ◽  
X. H. Ouyang
Keyword(s):  
Feedback Control ◽  
Computer Network ◽  
Optimal Feedback Control ◽  
Packet Losses ◽  
Quadratic Polynomials ◽  
Link Utilization ◽  
Stochastic Point Process ◽  
The Status ◽  
Feedback Laws ◽  
Recursive Search

We present an improved dynamic system that simulates the behavior of TCP flows and active queue management (AQM) system. This system can be modeled by a set of stochastic differential equations driven by a doubly stochastic point process with intensities being the controls. The feedback laws proposed monitor the status of buffers and multiplexor of the router, detect incipient congestion by sending warning signals to the sources. The simulation results show that the optimal feedback control law from the class of linear as well as quadratic polynomials can improve the system performance significantly in terms of maximizing the link utilization, minimizing congestion, packet losses, as well as global synchronization. The optimization process used is based on random recursive search technique known as RRS.

Formation Control of Under-Actuated Robotic Boats

2005 ◽  
Author(s):  
Farbod Fahimi ◽  
S. V. Sudhil Rineesh ◽  
C. Nataraj
Keyword(s):  
Feedback Control ◽  
Dynamic Model ◽  
Computer Simulations ◽  
Formation Control ◽  
Control Method ◽  
Degree Of Freedom ◽  
Input Output ◽  
Internal Dynamics ◽  
Control Laws ◽  
Three Degree Of Freedom

Feedback control laws for controlling multiple robotic boats in arbitrary formations are proposed. The presented formation control method uses only local sensor-based information. The method of input-output linearization has been used to exponentially stabilize the relative distance and orientation of neighboring boats with a three-degree-of-freedom dynamic model. It is shown that the internal dynamics of the system is also stable. The use of these control laws is demonstrated by computer simulations. These controllers can be utilized to control an arbitrarily large number of robotic boats moving in very general formations.

scholarly journals Vibration analysis of multi-body dynamic model of combat vehicle gearbox

2019 ◽  
Vol 287 ◽  
pp. 03005
Author(s):  
Jan Furch ◽  
Cao Vu Tran
Keyword(s):  
Dynamic Model ◽  
Vibration Signal ◽  
Technical Condition ◽  
Proposed Model ◽  
Combat Vehicle ◽  
Failure Conditions ◽  
The Individual ◽  
Multi Body ◽  
Material Wear ◽  
Body Dynamic

The combat vehicle gearbox, during the operation, generates vibration signals being related to the technical condition of gearbox. The analysis of the vibration signal could be used to determine accurately the behaviour of gearbox. Along with the development of the computer technology, the multi-body dynamic solution has been used widely to simulate, analyse, and determine the technical condition of gearbox. The purpose of this paper is to introduce the dynamic model of combat vehicle gearbox, and the simulation process based on the multi-body dynamic software, namely MSC.ADAMS. This proposed model allows the detection of failure conditions of individual gears and bearings in the gearbox. In this way, the fault conditions of the individual transmission components are identified. In the future, we would like to include a material wear module in the model, and we would like to model the life of the gearbox. We assume that we would also carry out accelerated tests of the gearbox to verify validity.

scholarly journals The use of tools and approaches of system dynamics in the analysis of the efficiency of BIM implementation and its impact on the management and planning of investments in the construction sector

2019 ◽  
Vol 279 ◽  
pp. 01011
Author(s):  
Martin Hotový
Keyword(s):  
Decision Making ◽  
System Dynamics ◽  
Dynamic Model ◽  
Investment Decision ◽  
Construction Sector ◽  
Strategic Investment ◽  
Investment Projects ◽  
Investment Decision Making ◽  
Proposed Model ◽  
The Impact

This paper presents the use of tools and approaches of system dynamics in the analysis of the efficiency of BIM tools implementation in relation to the management and planning of investments in the construction sector. The dynamic model based on the approach of system dynamics allows to simulate the impact rate (range) of BIM implementation in strategic investment decision-making in the construction sector. Based on the analysis, the key parameters critically affecting the large construction investment projects are determined. The proposed model is implemented as a submodel in the dynamic model designed for potential refinements in the strategic planning of the extent of investments into projects of civil infrastructure of the Czech Republic. The model allows to test different strategies in the virtual world before their implementation. The prediction of future developments based on the proposed model allows to streamline planning and decision-making processes.

Sign in / Sign up

Export Citation Format

Share Document