NeuraliNQ: a neural network method for the transient performance analysis in non-Markovian Queues

Preface to the Second Edition. Preface to the First Edition. 1. Introduction. 1.1 Motivation. 1.2 Methodological Background. 1.3 Basics of Probability and Statistics. 2. Markov Chains. 2.1 Markov Processes. 2.2 Performance Measures. 2.3 Generation Methods. 3. Steady-State Solutions of Markov Chains. 3.1 Solution for a Birth Death Process. 3.2 Matrix-Geometric Method: Quasi-Birth-Death Process. 3.3 Hessenberg Matrix: Non-Markovian Queues. 3.4 Numerical Solution: Direct Methods. 3.5 Numerical Solution: Iterative Methods. 3.6 Comparison of Numerical Solution Methods. 4. Steady-State Aggregation/Disaggregation Methods. 4.1 Courtois' Approximate Method. 4.2 Takahashi's Iterative Method. 5. Transient Solution of Markov Chains. 5.1 Transient Analysis Using Exact Methods. 5.2 Aggregation of Stiff Markov Chains. 6. Single Station Queueing Systems. 6.1 Notation. 6.2 Markovian Queues. 6.3 Non-Markovian Queues. 6.4 Priority Queues. 6.5 Asymmetric Queues. 6.6 Queues with Batch Service and Batch Arrivals. 6.7 Retrial Queues. 6.8 Special Classes of Point Arrival Processes. 7. Queueing Networks. 7.1 Definitions and Notation. 7.2 Performance Measures. 7.3 Product-Form Queueing Networks. 8. Algorithms for Product-Form Networks. 8.1 The Convolution Algorithm. 8.2 The Mean Value Analysis. 8.3 Flow Equivalent Server Method. 8.4 Summary. 9. Approximation Algorithms for Product-Form Networks. 9.1 Approximations Based on the MVA. 9.2 Summation Method. 9.3 Bottapprox Method. 9.4 Bounds Analysis. 9.5 Summary. 10. Algorithms for Non-Product-Form Networks. 10.1 Nonexponential Distributions. 10.2 Different Service Times at FCFS Nodes. 10.3 Priority Networks. 10.4 Simultaneous Resource Possession. 10.5 Prograrns with Internal Concurrency. 10.6 Parallel Processing. 10.7 Networks with Asymmetric Nodes. 10.8 Networks with Blocking. 10.9 Networks with Batch Service. 11. Discrete-Event Simulation. 11.1 Introduction to Simulation. 11.2 Simulative or Analytic Solution? 11.3 Classification of Simulation Models. 11.4 Classification of Tools in DES. 11.5 The Role of Probability and Statistics in Simulation. 11.6 Applications. 12. Performance Analysis Tools. 12.1 PEPSY. 12.2 SPNP. 12. 3 MOSEL-2. 12.4 SHARPE. 12.5 Characteristics of Some Tools. 13. Applications. 13.1 Case Studies of Queueing Networks. 13.2 Case Studies of Markov Chains. 13.3 Case Studies of Hierarchical Models. Glossary. Bibliography. Index.

The author presents computational techniques that extend and relate several approximation methods in reliability prediction and performance analysis. The approximation methods considered are those that tackle the problems that arise when a Markov or semi-Markov model has a mix of very slow rates and very fast rates. It is shown that the heuristic rule approximation from performance analysis and the instantaneous jump approximation from reliability modeling are mathematically equivalent. That is, the two methods alter the probabilities in the same way. The results obtained permit the computation of the probabilities and moments of complex fault recovery and system repair models. The results are useful when analyzing highly reliable or high-performance systems, and they are relevant for several reliability prediction packages and for a model reduction method in performance analysis. >

The adaptive filtering algorithm based on the maximum correntropy criterion (MCC) is very effective in suppressing non-Gaussian noises and therefore attracts widespread attentions. At present, some works have been done for study the convergence and steady-state performance analysis of the MCC algorithm, but its transient performance analysis is still an open problem. To provide a comprehensive theoretical foundation for the MCC algorithm, we propose a method for transient performance analysis based on moment generating function (MGF). Since this method can efficiently calculate the expected value of the exponential term in the iterative update equation, it can avoid the discrepancies caused by introducing some approximation methods such as Taylor expansions in the analysis process. To date, there is no precedent for using this method to analyze the transient performance of the MCC algorithm. In addition, the steady-state performance and stability conditions of the MCC algorithm are discussed based on this method. Finally, the proposed analytical method is applied to the system identification problem, and the results show that the theoretical analysis results are agree well with the Monte Carlo simulation results.

Athletes, both professional and amateur, are always looking for ways to improve their performance. With the introduction and increasing availability of modern technologies and smart devices arose the need to measure and analyze performance, but likewise, the use of these innovations as a competitive advantage also arose. Scientific publications reflect the wide range of available approaches and technologies, as well as the growing interest in various sports. As a result, we concentrated on a systematic review of publications that presented performance analysis tools and methods in all sports, with a final focus on racket sports. Clarivate Analytics’ Web of Science (WoS) and Elsevier Inc.’s SCOPUS databases were searched for 1147 studies that conducted performance analysis and sports research and were published in English. The data in the systematic review are current, up until 18 May 2021. A general review was performed on 759 items, and then 65 racket sports publications were thoroughly scrutinized. We concentrated on performance data, data collection and analysis tools, performance analysis methods, and software. We also talked about performance prediction. In performance research, we have identified specific approaches for specific sports as well as key countries. We are also considering expanding performance analysis in to E-sports in the future.

Embedded systems are computer systems that are deeply integrated in and interact with the physical world. The physical world often imposes strict timing constraints on these systems. Therefore, the correct operation of such systems depends not only on the values of the produced results, but also on their timing. Such systems are called real-time systems. Methods for system-level performance analysis play an integral part during the early design phase of embedded real-time systems. They support the analysis of various non-functional performance characteristics, and alleviate the choice of important design decisions before much time and resources are invested in detailed implementations. Compositional formal methods for performance analysis are able to quickly provide hard upper and lower bounds on performance characteristics. However, such analytical methods are limited in their scope and accuracy as they cannot incorporate many system details in the analysis. Interface-based design has been proposed in order to unify the steps of designing a system and analyzing it. It supports the paradigm for correct-by-construction design in the domain of embedded realtime systems. It can significantly shorten the design time of complex distributed embedded real-time systems. Recently, a method for Modular Performance Analysis based on Real-Time Calculus has been proposed that is also connected with the principles of interface-based design in the framework of Real-Time Interfaces. Both of them support the analysis and design of complex distributed embedded real-time systems. This thesis builds on these results and extends them in several directions. The main contributions of this work are summarized as follows: • A novel framework for interface-based design of distributed embedded real-time systems is proposed. It includes properties such as incremental design, independent-implementability, and refinement. It unifies many existing compositional performance analysis and interface-based design methods. • Novel models and methods for interface-based design are proposed that support the analysis and design of distributed embedded real-time systems which have buffer overflow and underflow constraints, end-to-end delay constraints, variable execution demands of tasks, and complex resource sharing policies. • A novel method for compositional performance analysis of marked graphs is proposed that can be used for distributed embedded real-time systems with cyclic data dependencies, finite buffers with blocking write semantics, variable execution demands of tasks, nondeterministic event streams and resource behaviors, and complex resource sharing policies. • A novel method for mode change performance analysis of multimode embedded real-time systems is proposed that can be used for systems with non-deterministic event streams and resource behaviors, variable execution demands of tasks, complex resource sharing policies, and various mode change protocols. • A novel scheduling server based on time division multiple access is proposed that can be reconfigured during run-time, and can guarantee the real-time properties of applications during reconfigurations.

The electromagnetic frequency regulator (EFR) device has proven to be an attractive solution for driving grid-connected electrical generators in distributed generation (DG) systems based on renewable energy sources (RES). However, the dynamic characteristic of the EFR has not yet been discussed for cases where its parameters vary from the nominal values. To evaluate this issue, this paper proposes a method for transient and steady-state performance analysis applied to the EFR device considering parametric variations. To perform this analysis, a dynamic model of the EFR device is derived, and its dynamic characteristics are discussed. Based on this model, the system’s controller gains are designed by using the root-locus method (RLM) to obtain the desired dynamic performance. Then, a sensitivity analysis of the closed-loop poles under the effect of parameters variation is performed. In addition, the paper also presents an analysis of the EFR-based system operating with the designed controllers. The proposed theoretical analysis is assessed using simulation and experimental results. The simulation program was developed using a Matlab/Simulink platform, while the experimental results were obtained through a laboratory setup emulating the EFR-based system.

For efficient design of regenerative blower used for fuel cell system, the design and the performance analysis methods of regenerative blower are developed, and CFD modelling and simulation are carried out on the designed blower. The design process of regenerative blower is conducted to determine the geometries of rotating impellers and stationary side channel with several design variables. The performance analysis on the designed blower is made by incorporating momentum exchange theory between impellers and side channel with mean line analysis method, and its pressure loss and leakage flow models are constructed from related fluid mechanics data and correlations which can be expressed in terms of blower design variables. The internal flow field of blower is analysed by using the CFX code, a CFD code specialized for fluid machinery. The present performance analysis method is applied to four existing models for verifying its prediction accuracy, and the comparison between the prediction and the test results are well-agreed with a few percentage of relative error. Furthermore, the present design and performance analysis methods are also applied in developing a new blower used for fuel cell application, and the newly designed blower is manufactured and tested through chamber-type test facility. The performance prediction by the present method is well-agreed with the test and the CFD simulation results. Therefore, from the comparison results, the prediction design and performance analysis methods are shown to be suitable for the actual design practice of regenerative blower.

With its high efficiency and low emissions, Solid Oxide Fuel Cell (SOFC) is a promising alternative solution for many applications including both stationary power plants and mobile Auxiliary Power Unit (APU) systems. In this paper, a dynamic model is developed for planar co-flow SOFCs for both transient and steady-state performance analysis. Finite volume method with user-defined grid is adopted to deal with the spatial distributions of current densities, pressures, temperatures and gas compositions in the SOFC. Simulations of both transient and steady state behaviors are performed to analyze the system performance. Fuel utilization, air excess ratio, air inlet temperature and current density are identified as critical operating parameters for steady-state performance in terms of cell efficiency, maximum temperature and temperature gradient in the Positive electrode-Electrolyte-Negative electrode (PEN) structure. Dynamic responses to step changes of fuel and air flow rates (two important control variables) and responses to the step change in load (the main disturbance) are analyzed to shed lights on feedback control design.

A performance simulation program for the turboprop engine (PT6A-62), which is the power plant of the first Korean indigenous basic trainer KT-1, was developed for performance prediction, development of an EHMS (Engine Health Monitoring System) and the flight simulator. Characteristics of components including compressors, turbines, power turbines and the constant speed propeller were required for the steady state and transient performance analysis with on and off design point analysis. In most cases, these were substituted for what scaled from similar engine components’ characteristics with the scaling law. The developed program was evaluated with the performance data provided by the engine manufacturer and with analysis results of GASTURB program, which is well known for the performance simulation of gas turbines. Performance parameters such as mass flow rate, compressor pressure ratio, fuel flow rate, specific fuel consumption and turbine inlet temperature were discussed to evaluate validity of the developed program at various cases. The first case was the sea level static standard condition and other cases were considered with various altitudes, flight velocities and part loads with the range between idle and 105% rotational speed of the gas generator. In the transient analysis, the Continuity of Mass Flow Method was utilized under the condition that mass stored between components is ignored and the flow compatibility is satisfied, and the Modified Euler Method was used for integration of the surplus torque. The transient performance analysis for various fuel schedules was performed. When the fuel step increase was considered, the overshoot of the turbine inlet temperature occurred. However, in case of ramp increase of the fuel longer than step increase of the fuel, the overshoot of the turbine inlet temperature was effectively reduced.

A performance simulation program for the turboprop engine (PT6A-62), which is the power plant of the first Korean indigenous basic trainer KT-1, was developed for more precise performance prediction, development of an EHMS (Engine Health Monitoring System) and the flight simulator. Characteristics of components including compressors, turbines, the combustor and the constant speed propeller were required for the steady state and transient performance analysis with on and off design point analysis. In most cases, these were substituted for what scaled from similar engine components’ characteristics with the scaling law. The developed program was evaluated with the performance data provided by the engine manufacturer and with analysis results of GASTURB program, which is well known for the performance simulation of gas turbines. Performance parameters such as mass flow rate, compressor pressure ratio, fuel flow rate, specific fuel consumption ratio and turbine inlet temperature were discussed to evaluate validity of the developed program at various cases. The first case was the sea level static standard condition and other cases were considered with various altitudes, flight velocities and part loads with the range between idle and 105% rotational speed of the gas generator. In the transient analysis, the Continuity of Mass Flow Method was utilized under the condition that mass stored between components is ignored and the flow compatibility is satisfied, and the Modified Euler Method was used for integration of the surplus torque. The transient performance analysis for various fuel schedules was performed. When the fuel step increase was considered, the overshoot of the compressor turbine inlet temperature occurred. However, in case of the fuel ramp increase longer than the fuel step increase, the overshoot of the compressor turbine inlet temperature was effectively reduced.

The purpose of this paper is to present a player-centred performance analysis method as an effective mechanism to enhance expert players’ performance in professional soccer. Data were collected through an application of a developed performance analysis method and subsequent unstructured interviews to explore participants’ experience of the applied methodology. Grounded by an enactive perspective of human activity, the applied methodology foregrounds the player’s intrinsic experience and places the player at the centre of the analysis and interpretation process. The sample included thirty professional soccer players with professional playing experience ranging from 2 years to 19 years and representing three professional teams. Using an interpretive data analysis approach results were considered from a methodological perspective concerning the core functions of a performance analysis method. Categories regarding performance analysis and performance development were highlighted. Findings demonstrate that adopting a player-centred approach to performance analysis in professional soccer provides advancement of the understanding of the collective performance of the expert player and may increase the opportunity for sustained learning.

Economic pressure to improve production efficiency in unconventional reservoirs has met a stiff challenge to scale up traditional reservoir modeling methods to the entire field for quantifying well performance. The main reasons are lack of availability of key reservoir and well parameters and difficulty to setup and maintain models because of the large well count and rapid pace of operations. As a result, decline curve analysis is still the prevailing method for large scale evaluations, which does not consider routine pressure variations and operational constraints. Analytical rate transient (RTA) models warrant identification of flow regimes and geometrical assumptions (well and fractures) to apply discrete analytical models for various flow segments. This inherent limitation of RTA makes it interpretive and not conducive to fieldscale application, besides often lacking necessary inputs for all wells. It is desirable to have better understanding through a robust and consistent well performance analysis method at field scale to unlock significant production optimization opportunities with existing field infrastructure and investment. We have applied a reduced physics formulation based on Dynamic Drainage Volume (DDV) using commonly measured data for most wells (namely, flowback data, daily production rates, and wellhead pressure) to calculate continuous pressure depletion, transient productivity index (PI) and inflow performance relationship (IPR). This transient well performance (TWP) method eliminates the surface and wellbore operational impacts to extract the true reservoir signal that can be used for robust well performance analysis and forecasting. We applied the TWP method in multiple basins with large well counts (more than 1000 wells) producing under a variety of methods. In this paper, we present several case studies illustrating various production optimization opportunities, focusing on naturally flowing and gas-lifted wells. The fluid properties and bottomhole pressure estimated using data-driven methods for all wells provided excellent match with blind data (PVT lab reports and downhole gauge data). The TWP method normalizes reservoir and completion quality to extract valuable insights on effectiveness of well and completions design in the presence of varying geological and fluid properties. The transient PI and dynamic IPR results provided valuable insights on how and when to select various artificial lift systems. During gas lift, we identified several wells that were over-injecting gas volumes at higher compressor discharge head, with line of sight to significant operational cost savings and reduced energy consumption. The proposed methodology combines pragmatic use of physics and data-driven methods to solve a critical need for analyzing unconventional reservoirs. Field application of the novel DDV method on large well population has been quite successful in identifying various optimization opportunities that would not have been possible, timely, or repeatable with other traditional methods.

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For efficient design process of regenerative blower, the present study provides new generalized pressure and leakage flow loss models, which can be used in the performance analysis method of regenerative blower. The present performance analysis on designed blower is made by incorporating momentum exchange theory between impellers and side channel with mean line analysis method, and its pressure loss and leakage flow models are generalized from the related fluid mechanics correlations which can be expressed in terms of blower design variables. The present performance analysis method is applied to four existing models for verifying its prediction accuracy, and the prediction and the test results agreed well within a few percentage of relative error. Furthermore, the present performance analysis method is also applied in developing a new blower used for fuel cell application, and the newly designed blower is manufactured and tested through chamber-type test facility. The performance prediction by the present method agreed well with the test result and also with the CFD simulation results. From the comparison results, the present performance analysis method is shown to be suitable for the actual design practice of regenerative blower.

Robot coordination and control systems for remote teleoperation applications are by necessity implemented on distributed computers. Modeling and performance analysis of these distributed robotic systems is difficult, but important for economic system design. Performance analysis methods originally developed for conventional distributed computer systems are often unsatisfactory for evaluating real-time systems. The paper introduces a formal model of distributed robotic control systems; and a performance analysis method, based on scheduling theory, which can handle concurrent hard-real-time response specifications. Use of the method is illustrated by a case of remote teleoperation which assesses the effect of communication delays and the allocation of robot control functions on control system hardware requirements.