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.     

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 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     

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     

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 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.     

Experimental evaluation of a reusability-oriented parallelprogramming environment

Reports on the initial experimental evaluation of ROPE (reusability-oriented parallel programming environment), a software component reuse system. ROPE helps the designer find and understand components by using a new classification method called structured relational classification. ROPE is part of a development environment for parallel programs which uses a declarative/hierarchical graphical programming interface. This interface allows use of components with different levels of abstraction, ranging from design units to actual code modules. ROPE supports reuse of all the component types defined in the development environment. Programs developed with the aid of ROPE were found to have error rates far less than those developed without ROPE     

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.     

Some problems of hardware and software performance evaluation

Translated from Kibernetika i Sistemnyi Analiz, No. 5, pp. 115–126, September–October, 1995.     

An ergonomic design and performance evaluation of pipettes

This paper describes the results of an investigation of the differences in performance, postures, strains on hand–arm–shoulder musculature, and subjective ratings of three pipettes (models A, B, and C). Both models A and B were pipettes available on the market. Model C was developed for this study of an ergonomically designed pipette. The gripping posture of the three models was distinct both in the anatomical and in the functional sense. Working with models A and B required a four-finger grasp with a thumb operated plunger. Model C required a finger–palmar power grip and the plunger was operated by the fingers. Performance evaluation of the different pipettes in different tasks indicated that using the proposed model C resulted in a 2–3% lower fault rate, a 10% shorter completion time, and the highest subjective ratings among the three. Postural analysis results indicated that when using model C, the shoulder was the least abducted, the wrist was the least extended, and the wrist was the least radially extended. Model C appeared to provide the greatest opportunity for delicate adjustments of posture in response to the activity of the skin receptors and reduced the strains on the upper body musculature, justifying the ergonomic input into the design.     

Anthropometry and hand performance evaluation of minority population

The goal of this research was to evaluate the hand anthropometrics and hand performances of the US minority population. This study had three specific objectives (1) to evaluate the anthropometrics of the US minority population and understand their variability within the general US population (2) to evaluate performance variation of the minority population for different hand conditions and (3) to develop models for a set of performance measures using the anthropometry of the upper extremity. Fifteen subjects from each of Hispanics, African Americans, Asian Indians and Vietnamese population groups participated in this study. Hand length, hand breadth, upper-arm length, forearm length, arm length and hand volume were the anthropometrics recorded. Hand performance dimensions including dexterity, tactility, manipulability, grip strength and a set of functional tasks were measured for bare hand and gloved (cotton, Kevlar, leather and vinyl) hand conditions. Anthropometric evaluations determined a significant effect of ethnicity and gender on hand length, forearm length, arm length and hand volume. Anthropometric comparisons determined that the ethnic groups represented different percentiles within the US population. Performance evaluations determined a significant effect of ethnicity, gender and glove type on the hand performances of the Minority population. The best models were obtained for grip strength as compared to dexterity and manipulability. More validation is required before generalizing the findings of this study.Relevance to industryWhile a number of studies have established differences in anthropometry among different ethnic populations, very few studies have addressed their effect on performance. This study provides fundamental information on the anthropometrics and its effect on hand performance of the minority population in US. The findings of this study will assist engineers to consider personnel variations (anthropometry and performance) to improve productivity. Hence it is very relevant to the industry.     

Analysis and performance evaluation of HYPERchannel access protocols

HYPERchannel [1,3,5,7] is a local network configuration with random access to the global transmission medium and with ‘Carrier Sense’ techniques. Conflicts are resolved by a fixed priority scheduling of retransmissions.This paper presents a performance evaluation of HYPERchannel access protocols for different types of user systems. Analytical results and asymptotic relations are obtained for the throughput of HYPERchannel under different load characteristics.The fixed priority rule for retransmissions discriminates against low priority users; a modification of the access scheme (‘Fair HYPERchannel’) is proposed which compensates for this undesirable effect. The performance of this new protocol version is also evaluated.In a final section, the access schemes of HYPERchannel are compared with similar access protocols.     

Steady-state performance evaluation of continuous mono-T-semiflow Petri nets

The number of states in discrete event systems can increase exponentially with respect to the size of the system. A way to face this state explosion problem consists of relaxing the system model, for example by converting it to a continuous one. In the scope of Petri nets, the firing of a transition in a continuous Petri net system is done in a real amount. Hence, the marking (state) of the net system becomes a vector of non-negative real numbers. The main contribution of the paper lies in the computation of throughput bounds for continuous Petri net systems with a single T-semiflow. For that purpose, a branch and bound algorithm is designed. Moreover, it can be relaxed and converted into a linear programming problem. Some conditions, under which the system always reaches the computed bounds, are extracted. The results related to the computation of the bounds can be directly applied to a larger class of nets called mono T-semiflow reducible.     

A performance evaluation of the expert system ANEMIA

This paper reports the results of an evaluation study of the current level of performance given by ANEMIA, a knowledge-based consultation system addressing the clinical problem of managing anemic patients. ANEMIA was developed on a mainframe using the AI programming scheme EXPERT and then translated into a version running on a personal computer. At present the system is able to provide assistance in the diagnosis and management of 65 disease entities. After extensive local testing of accuracy, completeness, and consistency of the knowledge base included into ANEMIA, we designed a study to evaluate whether the system is able to appropriately mirror also the reasoning of well-known hematologists other than those who provided the knowledge. We were also interested in testing whether there were conflicting opinions among hematologists. Thus, we designed a validation study in which ANEMIA's performance could be compared with that of six hematologists and the interexpert consensus evaluated. ANEMIA's overall performance was judged acceptable in 87% (26/30) of the cases, while expert evaluators agreed with their colleagues in 90% (27/30) of them. A low interexpert consensus was found: considering the ratings given by different hematologists to the same ANEMIA performance, complete agreement occurred only 47% of the time.     

A performance evaluation study of pipeline TMR systems

A distributed system in which a job can be broken into a number of subjobs which are processed sequentially at various processors is considered. The performance of such a system is then compared to the replicated (triple modular redundant, or TMR) version of the system in which each subjob will require concurrent replicated processing with majority voting. The effect of voting times and processor failure rates on the performance of the system is investigated with analytical approximations and computer simulations. The accuracy of the former is examined. The results indicate the possible existence of a threshold voting time, below which the TMR system performs better than the unreplicated one, and above which the situation is reversed. Such thresholds are observed, where possible, in systems with repairable servers, as well as in those with nonrepairable servers