Erratum to “Computing performance measures in a multi-class multi-resource processor-shared loss system” [European Journal of Operational Research 123 (2000) 61–72]

2001 ◽  
Vol 133 (3) ◽  
pp. 685
Author(s):  
O.Zeynep Akşin ◽  
Patrick T. Harker
Keyword(s):  
Performance Measures ◽  
Operational Research ◽  
Loss System ◽  
Computing Performance

scholarly journals The Power-Series Algorithm for Polling Systems with Time Limits

1998 ◽  
Vol 12 (2) ◽  
pp. 221-237 ◽  
Author(s):  
J. P. C. Blanc
Keyword(s):  
Power Series ◽  
Performance Measures ◽  
Optimization Problems ◽  
Gradient Methods ◽  
Optimal Time ◽  
Polling Systems ◽  
Mean Values ◽  
Time Limits ◽  
Computing Performance ◽  
Derivatives Of

This paper deals with evaluation and optimization of polling systems with time limits. Performance measures are evaluated with the power-series algorithm, a flexible technique for computing performance measures for multiqueue systems. The constant time limits are approximated by Erlang distributed variables. The algorithm is extended to compute derivatives of performance measures. This allows for optimization of cost functions with respect to the mean values of the time limits by gradient methods. Several properties of the optimal time limits are revealed by the numerical solution of various optimization problems.

Assessing Human Mobile Computing Performance by Fitts' Law

2008 ◽  
pp. 830-846 ◽  
Author(s):  
Thomas Alexander ◽  
Christopher Schlick ◽  
Alexander Sievert ◽  
Dieter Leyk
Keyword(s):  
Mobile Devices ◽  
Performance Measures ◽  
User Interfaces ◽  
Error Rate ◽  
Quantitative Estimation ◽  
Graphical User Interfaces ◽  
Regression Analyses ◽  
User Input ◽  
Fitts Law ◽  
Computing Performance

This chapter describes the interdependence between locomotion while walking and human input performance in mobile Human-Computer-Interaction (HCI). For the analysis of the interdependence, appropriate performance measures, for example, subjective workload ratings or error rate, have to be applied. The way in which Fitts’ law can enhance the analysis is explained. In an experiment with n=18 participants, the general indices of performance (bits per second) were measured while standing and walking with constant speed (2, 3.5, 5 km/h). Results show a significant increase of the error rate and a significant decrease of the index of performance for increased walking speed. Subsequent regression analyses allow quantitative estimation of these effects. The results show a division of the interdependence in two parts, based on the difficulty of the input task; they define threshold values for accuracy of user input. These values can be applied for the implementation and design of future Graphical User Interfaces (GUI) for mobile devices.

scholarly journals Application of Operational Research Techniques in Operating Room Scheduling Problems: Literature Overview

2018 ◽  
Vol 2018 ◽  
pp. 1-15 ◽  
Author(s):  
Şeyda Gür ◽  
Tamer Eren
Keyword(s):  
Operating Room ◽  
Performance Measures ◽  
Healthcare Costs ◽  
Operational Research ◽  
Patient Characteristics ◽  
Scheduling Problems ◽  
Operating Room Scheduling ◽  
Planning Strategy ◽  
Literature Overview

Increased healthcare costs are pushing hospitals to reduce costs and increase the quality of care. Operating rooms are the most important source of income and expense for hospitals. Therefore, the hospital management focuses on the effectiveness of schedules and plans. This study includes analyses of recent research on operating room scheduling and planning. Most studies in the literature, from 2000 to the present day, were evaluated according to patient characteristics, performance measures, solution techniques used in the research, the uncertainty of the problem, applicability of the research, and the planning strategy to be dealt within the solution. One hundred seventy studies were examined in detail, after scanning the Emerald, Science Direct, JSTOR, Springer, Taylor and Francis, and Google Scholar databases. To facilitate the identification of these studies, they are grouped according to the different criteria of concern and then, a detailed overview is presented.

scholarly journals Loss Systems with Slow Retrials in the Halfin–Whitt Regime

2013 ◽  
Vol 45 (01) ◽  
pp. 274-294 ◽  
Author(s):  
F. Avram ◽  
A. J. E. M. Janssen ◽  
J. S. H. Van Leeuwaarden
Keyword(s):  
Steady State ◽  
Critical Load ◽  
Performance Measures ◽  
System Performance ◽  
Economies Of Scale ◽  
Blocking Probability ◽  
Loss System ◽  
Qed Regime ◽  
Loss Systems ◽  
Steady State Performance

The Halfin–Whitt regime, or the quality-and-efficiency-driven (QED) regime, for multiserver systems refers to a situation with many servers, a critical load, and yet favorable system performance. We apply this regime to the classical multiserver loss system with slow retrials. We derive nondegenerate limiting expressions for the main steady-state performance measures, including the retrial rate and the blocking probability. It is shown that the economies of scale associated with the QED regime persist for systems with retrials, although in situations when the load becomes extremely critical the retrials cause deteriorated performance. Most of our results are obtained by a detailed analysis of Cohen's equation that defines the retrial rate in an implicit way. The limiting expressions are established by studying prelimit behavior and exploiting the connection between Cohen's equation and Mills' ratio for the Gaussian and Poisson distributions.

Assessing Human Mobile Computing Performance by Fitts' Law

2009 ◽  
pp. 206-224
Author(s):  
Thomas ◽  
Thomas ◽  
Schlick, Christopher Alexander ◽  
Alexander Sievert ◽  
Dieter Leyk
Keyword(s):  
Mobile Devices ◽  
Performance Measures ◽  
User Interfaces ◽  
Error Rate ◽  
Quantitative Estimation ◽  
Graphical User Interfaces ◽  
Regression Analyses ◽  
User Input ◽  
Fitts Law ◽  
Computing Performance

This chapter describes the interdependence between locomotion while walking and human input performance in mobile Human-Computer- Interaction (HCI). For the analysis of the interdependence, appropriate performance measures, for example, subjective workload ratings or error rate, have to be applied. The way in which Fitts’ law can enhance the analysis is explained. In an experiment with n=18 participants, the general indices of performance (bits per second) were measured while standing and walking with constant speed (2, 3.5, 5 km/h). Results show a significant increase of the error rate and a significant decrease of the index of performance for increased walking speed. Subsequent regression analyses allow quantitative estimation of these effects. The results show a division of the interdependence in two parts, based on the difficulty of the input task; they define threshold values for accuracy of user input. These values can be applied for the implementation and design of future Graphical User Interfaces (GUI) for mobile devices.

scholarly journals Loss Systems with Slow Retrials in the Halfin–Whitt Regime

2013 ◽  
Vol 45 (1) ◽  
pp. 274-294 ◽  
Author(s):  
F. Avram ◽  
A. J. E. M. Janssen ◽  
J. S. H. Van Leeuwaarden
Keyword(s):  
Steady State ◽  
Critical Load ◽  
Performance Measures ◽  
System Performance ◽  
Economies Of Scale ◽  
Blocking Probability ◽  
Loss System ◽  
Qed Regime ◽  
Loss Systems ◽  
Steady State Performance

The Halfin–Whitt regime, or the quality-and-efficiency-driven (QED) regime, for multiserver systems refers to a situation with many servers, a critical load, and yet favorable system performance. We apply this regime to the classical multiserver loss system with slow retrials. We derive nondegenerate limiting expressions for the main steady-state performance measures, including the retrial rate and the blocking probability. It is shown that the economies of scale associated with the QED regime persist for systems with retrials, although in situations when the load becomes extremely critical the retrials cause deteriorated performance. Most of our results are obtained by a detailed analysis of Cohen's equation that defines the retrial rate in an implicit way. The limiting expressions are established by studying prelimit behavior and exploiting the connection between Cohen's equation and Mills' ratio for the Gaussian and Poisson distributions.

A LOSS SYSTEM WITH SKILL-BASED SERVERS UNDER ASSIGN TO LONGEST IDLE SERVER POLICY

2012 ◽  
Vol 26 (3) ◽  
pp. 307-321 ◽  
Author(s):  
Ivo Adan ◽  
Gideon Weiss
Keyword(s):  
Steady State ◽  
Performance Measures ◽  
Service Time ◽  
Loss System ◽  
Steady State Distribution ◽  
State Distribution ◽  
Similar System ◽  
General Service

We consider a memoryless loss system with servers ${\cal S}$ = {1, …, J}, and with customer types ${\cal C}$ = {1, …, I}. Servers are multi-type: server j works at rate μj, and can serve a subset of customer types C(j). An arriving customer will go to the longest idling server which can serve him, or be lost. We obtain a simple explicit steady-state distribution for this system, and calculate various performance measures of this system in steady state. We provide some illustrative examples. We compare this system with a similar system discussed recently by Adan, Hurkens, and Weiss [1]. We also show that this system is insensitive, the results hold also for general service time distributions.

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