Modeling And Performance Evaluation Of Branch And Value Prediction In Ilp Processors

Speculative execution is one of the key issues to boost the performance of future generation microprocessors. In this paper, we introduce a novel approach to evaluate the effects of branch and value prediction, which allow the processor to execute instructions beyond the limits of control and true data dependences. Until now, almost all the estimations of their performance potential under different scenarios have been obtained using trace-driven or execution-driven simulation. Occasionally, some simple deterministic models have been used. We employ an analytical model based on recently introduced Fluid Stochastic Petri Nets (FSPNs) in order to capture the dynamic behavior of an ILP processor with aggressive use of prediction techniques and speculative execution. Here we define the FSPN model, derive the state equations for the underlying stochastic process and present performance evaluation results to illustrate its usage in deriving measures of interest. Our implementation-independent stochastic modeling framework reveals considerable potential for further research in this area using numerical solution of systems of partial differential equations and/or discrete-event simulation of FSPN models.     

A hybrid model for real time simulation of urban traffic

In this paper a hybrid model is presented to predict the behavior of traffic in urban area. Intersections and on/off-ramps are modeled by Colored Timed Petri Nets while road links are modeled by a stochastic discrete time model. It is assumed that vehicle routings at each intersection are stochastic. A Particle Filter algorithm based on the hybrid model is developed to estimate the system state. The validation of the model by using real data is discussed. The limited computational effort required makes the model suitable to be used in simulation-based control schemes for urban traffic.     

基于动态影响网的C2组织COA问题建模

提出了用动态影响网(Dynamic Influence Nets,DINs)对指挥控制(Command and Control,C2)组织行动过程(Course of Actions,COA)问题进行建模的方法。该方法通过引入因果强度参数,替代了传统动态贝叶斯网络中的条件概率表。给出了利用因果强度参数进行概率传播的具体计算方法。结合一个联合作战的仿真算例,验证了该建模方法的优越性和有效性。     

基于抑制弧Petri网的离散事件系统的监控理论综述

利用Petri网的抑制弧实现离散事件系统的监控是离散事件系统监控理论的一个新进展。对抑制弧Petri网作了简单的介绍，并给出了该监控理论的基本原理．详细地回顾和总结了该理论的四种方法，即：结合自动机的字符串避免方法、抑制弧方法、基于抑制弧的状态避免控制器方法以及加权抑制弧方法，分别分析了这几种方法各自的利弊。最后对其可能的发展作了展望。     

通用网在模拟无序信息传输中的应用

传输信息常涉及到不同的难题。当保护信息免受非控制访问时，一个新的似然性可能得以应用，即无序。由于在安全通信中实施无序的兴趣日见增加，已经提出许多设计方案。本文提出了建立非线性动态无序系统模型的方法，并进行了通用网的设计与访真。     

基于Matlab环境的Petri网的仿真方法

该文介绍了佩特利网(Petri网)和Statefow的基本概念，给出Petri网在Matlab环境下的仿真方法．并以单水箱系统的混合Petri网模型为例进行说明，结合仿真结果对Peri网的性能进行了初步分析。     

基于UML/APN集成建模技术的ISCM模型研究

以集成供应链管理(ISCM)软件开发项目为研究背景，阐述UML与智能Petri网(APN)相结合的集成建模方法。首先用UML方法构建ISCM库存系统的结构模型和行为模型，用APN方法构建库存系统的Petri网模型；然后用模拟仿真器模拟验证APN模型，进而用APN模型来优化完善UML对象模型；最后用OOPL实现经模拟验证与优化的目标模型。所提出的集成建模方法和研究模型在ISCM软件产品开发中取得了良好的效果。     

离散时间Petri网的模糊模型

离散时间Petri网是一种系统模拟和分析的有效工具，它可以结合图形和分析描述评估离散事件系统的动态执行．基于T—S模糊模型，提出用于描述离散时间Petri网的模糊模型，讨论该模型适应于TtPNs的情况，用以推广文章结论，并且给出用于TtPNs的线性模糊控制规则．同时，文章还给出TtPNs聚合的结论．     

Analyzing User-Perceived Dependability and Performance Characteristics of Voting Algorithms for Managing Replicated Data

User-perceived dependability and performance metrics are very different from conventional ones in that the dependability and performance properties must be assessed from the perspective of users accessing the system. In this paper, we develop techniques based on stochastic Petri nets (SPN) to analyze user-perceived dependability and performance properties of quorum-based algorithms for managing replicated data. A feature of the techniques developed in the paper is that no assumption is made regarding the interconnection topology, the number of replicas, or the quorum definition used by the replicated system, thus making it applicable to a wide class of quorum-based algorithms. We illustrate this technique by comparing conventional and user-perceived metrics in majority voting algorithms. Our analysis shows that when the user-perceiveness is taken into consideration, the effect of increasing the network connectivity and number of replicas on the availability and dependability properties perceived by users is very different from that under conventional metrics. Thus, unlike conventional metrics, user-perceived metrics allow a tradeoff to be exploited between the hardware invested, i.e., higher network connectivity and number of replicas, and the performance and dependability properties perceived by users.     

Combined Petri net modelling and AI-based heuristic hybrid search for flexible manufacturing systems—part II. Heuristic hybrid search

This two-part paper presents modelling and scheduling approaches of flexible manufacturing systems using Petri nets (PNs) and artificial intelligence (AI)-based heuristic search methods. In Part I, PN-based modelling approaches and basic AI-based heuristic search algorithms were presented. In Part II, a new heuristic function that exploits PN information is proposed. Heuristic information obtained from the PN model is used to dramatically reduce the search space. This heuristic is derived from a new concept, the resource cost reachability matrix, which builds on the properties of B-nets proposed in Part I. Two hybrid search algorithms, (1) an approach to model dispatching rules using analysis information provided by the PN simulation and (2) an approach of the modified stage-search algorithm, are proposed to reduce the complexity of large systems. A random problem generator is developed to test the proposed methods. The experimental results show promising results.