An Approximation Method for Blocking Probabilities in M/D/1/K1→ ⋅/D/1/K2Queues

2015 ◽  
Vol 32 (03) ◽  
pp. 1550017 ◽  
Author(s):  
Dong-Won Seo ◽  
Jinpyo Lee ◽  
Byeong-Yun Chang
Keyword(s):  
Approximation Method ◽  
Blocking Probability ◽  
Waiting Times ◽  
Tail Probability ◽  
System Structure ◽  
Finite Buffer ◽  
Tandem Queue ◽  
Policy System ◽  
Blocking Probabilities ◽  
The Difference

Obtaining exact blocking probabilities for tandem queues with finite capacities is not a trivial problem. In this paper, we propose a computational approximation method using max-plus algebra for computing blocking probability in a Poisson-driven 2-node tandem queue with finite capacities and constant service times. The blocking probability of a finite-capacity queueing system can be obtained from either the tail probability of stationary waiting time or the difference between two expected stationary waiting times at the first node of the corresponding extended 3-node tandem queue. The computational results in this study show that the proposed approach provides a good approximation of the blocking probability, and in particular, it works well under moderately to heavily loaded situations. The proposed approach is not limited to a particular blocking policy, system structure, or service time; hence, it is applicable to general queues with finite buffer capacities and various blocking policies.

Asymptotic Estimates for Blocking Probabilities in a Large Multi-Rate Loss Network

1997 ◽  
Vol 29 (3) ◽  
pp. 806-829 ◽  
Author(s):  
A. Simonian ◽  
J. W. Roberts ◽  
F. Théberge ◽  
R. Mazumdar
Keyword(s):  
Critical Load ◽  
Blocking Probability ◽  
Asymptotic Estimates ◽  
Switched Network ◽  
Blocking Probabilities ◽  
Low Load ◽  
Rate Loss ◽  
Load Conditions

In this paper, asymptotic estimates for the blocking probability of a call pertaining to a given route in a large multi-rate circuit-switched network are given. Concentrating on low load and critical load conditions, these estimates are essentially derived by using probability change techniques applied to the distribution of the number of occupied links. Such estimates for blocking probabilities are also given a uniform expression applicable to both load regimes. This uniform expression is numerically validated via simple examples.

scholarly journals Novel nonlinear control structure for vector control of SPIM drive using BS PCH

2020 ◽  
Vol 11 (2) ◽  
pp. 1099
Author(s):  
Ngoc Thuy Pham
Keyword(s):  
Nonlinear Control ◽  
Vector Control ◽  
Closed Loop ◽  
System Structure ◽  
Current Loop ◽  
Equation Resolution ◽  
Damping Matrix ◽  
Current Controller ◽  
Novel Structure ◽  
The Difference

This paper presents a novel structure combining the port-controlled Hamiltonian (PCH) and Backstepping (BS) nonlinear control for the vector control of the six-phase induction motor (SPIM). In this new scheme, to improve the outer loop’s robustness, the BS technique using the integral tracking errors action is proposed in the speed and flux controllers design. The advantage of this proposed control law is not to increase the complexity of differential equation resolution due to being not increased system states numbers. To enhance more the performance of SPIM drives (SPIMD), port-controlled Hamiltonian (PCH) scheme is used in the inner current loop controllers. In this proposed PCH current controller, the stabilization of controller is achieved via system passivity. In that, the interconnection and damping matrix functions of PCH system are shaped so that the physical (Hamiltonian) system structure is preserved at the closed loop level and the closed loop energy function is equal to the difference between the physical energy of the system and the energy supplied by the controller. The proposed control design is based on combination PCH and BS techniques improve significantly performance and robustness. The proposed speed control scheme is validated by Matlab-Simulink software.

Routing Based on Security

2014 ◽  
pp. 365-380
Author(s):  
I. A. Almerhag
Keyword(s):  
Network Security ◽  
Standard Method ◽  
Blocking Probability ◽  
Computational Effort ◽  
Routing Algorithms ◽  
Measure Data ◽  
Security Metrics ◽  
Essential Requirement ◽  
Blocking Probabilities ◽  
Common Technique

Even though it is an essential requirement of any computer system, there is not yet a standard method to measure data security, especially when sending information over a network. However, the most common technique used to achieve the three goals of security is encryption. Three security metrics are derived from important issues of network security in this chapter. Each metric demonstrates the level of achievement in preserving one of the security goals. Routing algorithms based on these metrics are implemented to test the proposed solution. Computational effort and blocking probability are used to assess the behavior and the performance of these routing algorithms. Results show that the algorithms are able to find feasible paths between communicating parties and make reasonable savings in the computational effort needed to find an acceptable path. Consequently, higher blocking probabilities are encountered, which is the price to be paid for such savings.

Service Science and Automation Laws

2009 ◽  
pp. 254-276 ◽  
Author(s):  
Andrew Targowski
Keyword(s):  
System Approach ◽  
Systems Design ◽  
User Involvement ◽  
Service Systems ◽  
Service Science ◽  
System Structure ◽  
New Information ◽  
The Difference ◽  
Systems Architectures ◽  
Generic Service

The purpose of this chapter is to define a scope of service science and service automation in service economy based on ideal generic service systems originally developed by the author. There are two goals of this study: 1) to develop generic service categories and their generic systems, and 2) to define a scope of service science based upon the presented generic models of service systems, which determine the required support from emerging system science. The research methodology is based on the architectural modeling according the paradigm of enterprise-wide systems (Targowski, 2003). The architectural system approach is based on the philosophy of the system approach (Klir, 1985), and management cybernetics (Beer, 1981) which provide comprehensive and cohesive solutions to the problems of systems design, thus eliminating the fuziveness of the “application portfolio” and the “information archipelago” (McFarlan, 1981; Targowski, 1990). The mission of the architectural system approach is to find the ultimate synthesis of the whole system structure that involves appropriate logic, appropriate technological accommodation, operational quality, a positive user involvement, and co-existence with nature (Targowski, 1990). In its nature, the architectural system approach is of deductive rather than inductive nature. It looks for the ideal model of a solution, which in practice is far away from its perfect level. The difference between the architectural system approach and the engineering approach is in the level of abstraction. The architectural models are more conceptual whereas engineering outcomes are more technical and specific. The architectural system approach is the response to the complexity of expected outcomes. Prior to spending a few million dollars for a new information system, one must provide its information architecture and the business and social implications associated with it (Targowski, 2003). In this sense, this study will define service systems’ architectures.

scholarly journals Exceedance of power barriers for integrated continuous-time stationary ergodic stable processes

2009 ◽  
Vol 41 (03) ◽  
pp. 874-892
Author(s):  
Uğur Tuncay Alparslan
Keyword(s):  
Continuous Time ◽  
Stable Process ◽  
Tail Probability ◽  
Exceedance Probability ◽  
Dependence Structure ◽  
Stable Processes ◽  
Limiting Behavior ◽  
Order Of Magnitude ◽  
The Difference ◽  
Conservative Flow

We study the asymptotic behavior of the tail probability of integrated stable processes exceeding power barriers. In the first part of the paper the limiting behavior of the integrals of stable processes generated by ergodic dissipative flows is established. In the second part an example with the integral of a stable process generated by a conservative flow is analyzed. Finally, the difference in the order of magnitude of the exceedance probability in the two cases is related to the dependence structure of the underlying stable process.

scholarly journals Queuing System with Unreliable Servers and Inhomogeneous Intensities for Analyzing the Impact of Non-Stationarity to Performance Measures of Wireless Network under Licensed Shared Access

Mathematics ◽  
2020 ◽  
Vol 8 (5) ◽  
pp. 800 ◽  
Author(s):  
Ekaterina Markova ◽  
Yacov Satin ◽  
Irina Kochetkova ◽  
Alexander Zeifman ◽  
Anna Sinitcina
Keyword(s):  
Performance Measures ◽  
Blocking Probability ◽  
Radio Resource Management ◽  
Queuing System ◽  
Finite Buffer ◽  
Data Traffic ◽  
Multiservice Networks ◽  
Limited Frequency ◽  
The Impact

Given the limited frequency band resources and increasing volume of data traffic in modern multiservice networks, finding new and more efficient radio resource management (RRM) mechanisms is becoming indispensable. One of the implemented technologies to solve this problem is the licensed shared access (LSA) technology. LSA allows the spectrum that has been licensed to an owner, who has absolute priority on its utilization, to be used by other participants (i.e., tenants). Owner priority impacts negatively on the quality of service (QoS) by reducing the data bit rate and interrupting user services. In this paper, we propose a wireless multiservice network scheme model described as a queuing system with unreliable servers and a finite buffer within the LSA framework. The aim of this work is to analyze main system performance measures: blocking probability, average number of requests in queue, and average queue length depending on LSA frequencies’ availability.

Experimental Estimation of Fluidization Parameters - A Stochastic Approximation Method Approach

2010 ◽  
Vol 8 (1) ◽  
Author(s):  
Bachtiyar M. Yakubov ◽  
Eduard Yakubov ◽  
Victor A. Gotlib
Keyword(s):  
Stochastic Approximation ◽  
Approximation Method ◽  
Solid Particles ◽  
Diffusion Type ◽  
Difference Form ◽  
The Difference ◽  
Process Observation ◽  
Fluidization Process ◽  
Estimation Parameters ◽  
Method Approach

The paper deals with the use of the stochastic approximation method for estimation parameters of the fluidization process and detecting a change of the process mode based on experimental photographs of local part. The fluidization process is treated as a process of diffusion type, described by the diffusive equation. Because the solid particles are essentially discrete ones and the moments of process observation are also discrete, the diffusive equation is treated in the difference form. The problem of modeling of the fluidized bed is reduced to the estimation of coefficients of difference equations system. The method of stochastic approximation is used for this estimation. The method allows identifying the regime of the fluidization process in its dynamics and estimating the parameters of the process. The approach and the estimating algorithm were verified using the especial experiments.

Combined effects of contrast between poor and rich patches and overall nitrate concentration on Arabidopsis thaliana root system structure

2011 ◽  
Vol 38 (5) ◽  
pp. 364 ◽  
Author(s):  
Manuel Blouin ◽  
Ruben Puga-Freitas
Keyword(s):  
Root System ◽  
Nutrient Status ◽  
System Structure ◽  
System Response ◽  
Correlative Inhibition ◽  
The Rich ◽  
The Difference ◽  
Set Up ◽  
The Cost

The law of correlative inhibition states that roots in a richer environment develop more intensively if other roots of the same plant are in a poorer environment. This probably occurs only when the cost of emitting these roots in the rich patch is compensated by the advantage of having more roots, i.e. in situations where the difference in concentration between rich and poor patches is strong or the overall nutrient amount in the environment is low. For the first time, we tested root system response to combined gradients of contrast between poor and rich patches and of overall NO3– concentration in agar gels. We set up a factorial in vitro experiment crossing contrast (null, weak, strong heterogeneity) with overall NO3– concentration (deficient, optimal, excessive). We observed an increase in ramification density with increasing heterogeneity in deficient situations; but a decrease with increasing heterogeneity in excessive situations. The interaction between overall NO3– concentration and heterogeneity had a significant effect on root ramification density and the distribution of root length in diameter classes. The overall nutrient status of the soil has to be considered to understand the effect of heterogeneity on plant development at the morphological as well as at the molecular level.

scholarly journals How Active is Active Learning: Value Function Method Versus an Approximation Method

2020 ◽  
Vol 56 (3) ◽  
pp. 675-693
Author(s):  
Hans M. Amman ◽  
Marco P. Tucci
Keyword(s):  
Active Learning ◽  
Approximation Method ◽  
Function Method ◽  
Value Function ◽  
Stationary Process ◽  
Nonstationary Process ◽  
Function Approach ◽  
The Difference ◽  
The Value Function

AbstractIn a previous paper Amman et al. (Macroecon Dyn, 2018) compare the two dominant approaches for solving models with optimal experimentation (also called active learning), i.e. the value function and the approximation method. By using the same model and dataset as in Beck and Wieland (J Econ Dyn Control 26:1359–1377, 2002), they find that the approximation method produces solutions close to those generated by the value function approach and identify some elements of the model specifications which affect the difference between the two solutions. They conclude that differences are small when the effects of learning are limited. However the dataset used in the experiment describes a situation where the controller is dealing with a nonstationary process and there is no penalty on the control. The goal of this paper is to see if their conclusions hold in the more commonly studied case of a controller facing a stationary process and a positive penalty on the control.

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