Windows环境下Profibus-FMS通信程序的开发与实现

本文介绍了如何借助SAPI-FMS编程接口使自己开发的设备进入Prifubus-FMS网络,主要介绍了读写网络变量以及向网络增加变量的方法和过程。     

Experimental evaluation of linear time-invariant models for feedback performance control in real-time systems

In recent years a new class of soft real-time applications operating in unpredictable environments has emerged. Typical for these applications is that neither the resource requirements nor the arrival rates of service requests are known or available a priori. It has been shown that feedback control is very effective to support the specified performance of dynamic systems that are both resource insufficient and exhibit unpredictable workloads. To efficiently use feedback control scheduling it is necessary to have a model that adequately describes the behavior of the system. In this paper we experimentally evaluate the accuracy of four linear time-invariant models used in the design of feedback controllers. We introduce a model (DYN) that captures additional system dynamics, which a previously published model (STA) fails to include. The accuracy of the models are evaluated by validating the models with regard to measured data from the controlled system and through a set of experiments where we evaluate the performance of a set of feedback control schedulers tuned using these models. From our evaluations we conclude that second order models (e.g., DYN) are more accurate than first order models (e.g. STA). Further we show that controllers tuned using second order models perform better than controllers tuned using first order models.     

Experimental analysis of the root causes of performance evaluation results: a backfilling case study

The complexity of modern computer systems may enable minor variations in performance evaluation procedures to actually determine the outcome. Our case study concerns the comparison of two parallel job schedulers, using different workloads and metrics. It shows that metrics may be sensitive to different job classes, and not measure the performance of the whole workload in an impartial manner. Workload models may implicitly assume that some workload attribute is unimportant and does not warrant modeling; this too can turn out to be wrong. As such effects are hard to predict, a careful experimental methodology is needed in order to find and verify them.     

System-level performance evaluation of reconfigurable processors

Reconfigurable architectures that tightly integrate a standard CPU core with a field-programmable hardware structure have recently been receiving increased attention. The design of such a hybrid reconfigurable processor involves a multitude of design decisions regarding the field-programmable structure as well as its system integration with the CPU core. Determining the impact of these design decisions on the overall system performance is a challenging task. In this paper, we first present a framework for the cycle-accurate performance evaluation of hybrid reconfigurable processors on the system level. Then, we discuss a reconfigurable processor for data-streaming applications, which attaches a coarse-grained reconfigurable unit to the coprocessor interface of a standard embedded CPU core. By means of a case study we evaluate the system-level impact of certain design features for the reconfigurable unit, such as multiple contexts, register replication, and hardware context scheduling. The results illustrate that a system-level evaluation framework is of paramount importance for studying the architectural trade-offs and optimizing design parameters for reconfigurable processors.     

掌纹鉴别自动性能评估

研究关于掌纹鉴别系统的性能评测问题,设计并实现了一个用于性能评测的自动测试系统（ASPE）,此系统采用的是掌纹识别系统的处理核心。同时还提出了一种基于特征点（终点和分叉点）的评测方法和用于量化评估的俩个主要指标-召回率和准确率.此系统可以直接在样张上显示标准特征点和提取特征点,方便开发人员的对比并发现问题,从速度和精确度的测试结果看出自动的性能评测在效率和准确上都大大超过了人工测试。     

Experimental evaluation of expert fusion strategies

We investigate the classifier combination models presented in (Kittler et al., 1998; Kittler, 1998) and validate them experimentally. We emulate the behaviour of individual experts by subjecting their nominal soft outputs to perturbation errors. A relation between the effectiveness of various combination strategies and estimation errors is established.     

A performance evaluation of distributed database architectures

The globally integrated contemporary business environment has prompted new challenges to database architectures in order to enable organizations to improve database applications performance, scalability, reliability and data privacy in adapting to the evolving nature of business. Although a number of distributed database architectures are available for choice, there is a lack of an in‐depth understanding of the performance characteristics of these database architectures in a comparison way. In this paper, we report a performance study of three typical (centralized, partitioned and replicated) database architectures. We used the TPC‐C as the evaluation benchmark to simulate a contemporary business environment, and a commercially available database management system that supports the three architectures. We compared the performance of the partitioned and replicated architectures against the centralized database, which results in some interesting observations and practical experience. The findings and the practice presented in this paper provide useful information and experience for the enterprise architects and database administrators in determining the appropriate database architecture in moving from centralized to distributed environments. Copyright © 2012 John Wiley & Sons, Ltd.     

A performance evaluation of three multiagent platforms

In the last few years, many researchers have focused on testing the performance of Multiagent Platforms. Results obtained show a lack of performance and scalability on current Multiagent Platforms, but the existing research does not tackle poor efficiency causes. This article is aimed not only at testing the performance of Multiagent Platforms but also the discovery of Multiagent Platform design decisions that can lead to these deficiencies. Therefore, we are able to understand to what extent the internal design of a Multiagent Platform affects its performance. The experiments performed are focused on the features involved in agent communication.     

Internet of Things-based student performance evaluation framework

In recent years, solutions based on Internet of Things (IoT) are gaining impetus in educational institutions. It is observed that student performance evaluation system in education institutions is still manual. The performance score of student in traditional evaluation system is confined to its academic achievements while activity-based performance attributes are overlooked. Moreover, the traditional system fails to capitalise information of each student related to different activities in learning environment. In relation to this context, we propose to facilitate automated student performance evaluation system by exploring ubiquitous sensing capabilities of IoT. The system deduces important results about the performance of the students by discovering daily spatial–temporal patterns. These patterns are based on the data collected by the sensory nodes (objects) in the institution learning environment. The information is generated by applying data mining algorithms for each concerned activity. The automated decisions are taken by management authority for each student using game theory. In addition, to effectively manage IoT-based activity data, tensor-based storage mechanism is proposed. The experimental evaluation compares the student performance score generated by the proposed system with the manual student performance evaluation system. The results depict that the proposed system evaluates the performance of the student efficiently.     

高性能计算系统性能评测关键问题探讨

本文介绍了 HPC(高性能计算)系统评测理论和评测方法.同时介绍了我们在引进 HPC 系统时设计的评测方案以及在招投标过程中所综合考虑的各类技术要求,评测结果表明我们设计的方案能够很好的满足气象业务需求.同时对评测结果进行了理论分析,分析结论对相关业务需求的 HPC 系统建设具有一定的实际意义.     

Empirical performance evaluation of graphics recognition systems

Presents a methodology for evaluating graphics recognition systems operating on images that contain straight lines, circles, circular arcs, and text blocks. It enables an empirical comparison of vectorization software packages and uses practical performance evaluation methods that can be applied to complete vectorization systems. The methodology includes a set of matching criteria for pairs of graphical entities, a set of performance evaluation metrics, and a benchmark for the evaluation of graphics recognition systems. The benchmark was tested on three systems. The results are reported and analyzed in the paper     

A comprehensive performance evaluation of crossbar networks

A comprehensive model for evaluating crossbar networks in which the memory bandwidth and processor acceptance probability are primary measures considered is presented. This analytical model includes all important network control policies, such as the bus arbitration and rejected request handling policies, as well as the home memory concept. Computer simulation validates the correctness of the model. It is confirmed that the home memory and dynamic bus arbitration policy improve the network performance     

ZigBee路由协议分析与性能评估

在分析了ZigBee网络层各项关键技术的基础上,深入研究了ZigBee路由协议,并通过网络仿真器NS-2对其性能进行了仿真,仿真结果显示采用Cluster-Tree和AODVjr（Ad-hoc On-Demand distance Vector junior routing）相结合的ZigBee路由协议在ZigBee网络中具有较好的性能。     

地震灾害下应急物流系统绩效评价

针对地震灾害下应急物流系统(ELS)绩效评价的问题,以地震灾害下的应急物流系统为研究对象,首先建立了ELS运作模型,并对该运作模型进行了分析;然后构建了地震灾害下应急物流系统绩效评价指标体系,并在上述基础上建立了基于BP神经网络的评价模型;最后将该评价方法应用于实例,验证了该评价方法的科学性和实用性。     

Towards high performance security policy evaluation

The Enterprise Privacy Authorization Language (EPAL) is a formal language for specifying fine-grained enterprise privacy policies. With the adoption of EPAL, especially in web applications, the performance of EPAL policy evaluation engines becomes a critical issue. In this paper, we propose Eengine, an engine for efficient EPAL policy evaluation. Eengine first converts all string values in an EPAL policy to numerical values. Second, it converts a numericalized EPAL policy specified as a list of rules following the first-match semantics to a tree structure for efficient processing of numericalized requests.     

SPEC as a performance evaluation measure

Potential computer system users or buyers usually employ a computer performance evaluation technique only if they believe its results provide valuable information. System Performance Evaluation Cooperative (SPEC) measures are perceived to provide such information and are therefore the ones most commonly used. SPEC measures are designed to evaluate the performance of engineering and scientific workstations, personal vector computers, and even minicomputers and superminicomputers. Along with the Transaction Processing Council (TPC) measures for database I/O performance, they have become de facto industry standards, but do SPEC's evaluation outcomes actually provide added information value? In this article, we examine these measures by considering their structure, advantages and disadvantages. We use two criteria in our examination: are the programs used in the SPEC suite properly blended to reflect a representative mix of different applications, and are they properly synthesized so that the aggregate measures correctly rank computers by performance? We conclude that many programs in the SPEC suites are superfluous; the benchmark size can be reduced by more than 50%. The way the measure is calculated may cause distortion. Substituting the harmonic mean for the geometric mean used by SPEC roughly preserves the measure, while giving better consistency. SPEC measures reflect the performance of the CPU rather than the entire system. Therefore, they might be inaccurate in ranking an entire system. To remedy these problems, we propose a revised methodology for obtaining SPEC measures     

Experimental evaluation of pheromone models in ACOPlan

In this paper the system ACOPlan for planning with non uniform action cost is introduced and analyzed. ACOPlan is a planner based on the ant colony optimization framework, in which a colony of planning ants searches for near optimal solution plans with respect to an overall plan cost metric. This approach is motivated by the strong similarity between the process used by artificial ants to build solutions and the methods used by state?Cbased planners to search solution plans. Planning ants perform a stochastic and heuristic based search by interacting through a pheromone model. The proposed heuristic and pheromone models are presented and compared through systematic experiments on benchmark planning domains. Experiments are also provided to compare the quality of ACOPlan solution plans with respect to state of the art satisficing planners. The analysis of the results confirm the good performance of the Action?CAction pheromone model and points out the promising performance of the novel Fuzzy?CLevel?CAction pheromone model. The analysis also suggests general principles for designing performant pheromone models for planning and further extensions of ACOPlan to other optimization models.     

Experimental evaluation of distributed load balancing implementations

The evaluation of load balancing algorithms for use in general-purpose distributed systems has traditionally been carried out by discrete event simulation. This paper describes a testbed which supports the artificial creation of workload and the measurement of performance for load balancing algorithm implementations based on job migration in a small distributed system. Nine load balancing algorithms are implemented and evaluated under a range of environmental conditions. The experimental results confirm the effectiveness of load balancing and indicate the superiority of the centralised non-adaptive and distributed adaptive approaches. © 1998 John Wiley & Sons, Ltd.