Optimal imperfect preventive maintenance policies for a used system

In some practical situations, it may be more economical to work a used system than do a new one. From this viewpoint, this article considers three basic preventive maintenance (PM) policies for a used system: the system with initial variable damage Y ₀ begins to operate at time 0, and suffers damage due to shocks. It fails when the total damage exceeds a failure level K and corrective maintenance is made immediately. To prevent such failure, it undergoes PM at a planned time T, a shock number N and a damage level k, but maintenances are imperfect. However, failure rate of a used system maybe higher than that of a new one, so some maintenance is applied to the policies at each shock in the extended models. Using the theory of cumulative processes, expected cost rate models are obtained, optimal policies which minimise them are derived analytically and discussed numerically.     

An economic production quantity model for deteriorating items with preventive maintenance policy and random machine breakdown

In recent years, many researches on economic production quantity (EPQ) models with machine breakdown and preventive maintenance have been developed, but few of them have developed integrated models for deteriorating items. In this study, we develop EPQ models for deteriorating items with preventive maintenance, random machine breakdown and immediate corrective action. Corrective and preventive maintenance times are assumed to be stochastic and the unfulfilled demands are lost sales. Two EPQ models of uniform distribution and exponential distribution of corrective and maintenance times are developed. An example and sensitivity analysis is given to illustrate the models. For the exponential distribution model, it is shown that the corrective time parameter is one of the most sensitive parameters to the optimal total cost.     

Developer social networks in software engineering:construction,analysis,and applications

With the increasing popularity of Internet, more and more developers are collaborating together for software development. During the collaboration, a lot of information related to software development, including communication and coordination information of developers, can be recorded in software repositories. The information can be employed to construct Developer Social Networks （DSNs） for facilitating tasks in software engineering. In this paper, we survey recent advances of DSNs and examine three fundamental steps of DSNs, namely construction, analysis, and applications. We summarize the state-of-the-art methods in the three steps and investigate the relationships among them. Furthermore, we discuss the main issues and point out the future opportunities in the study of DSNs.     

基于构件软件的可靠性分析技术—FTA

快速、高效是软件开发追逐的目标,集中体现软件复用思想的基于构件软件技术继面向对象技术后成为现今软件工程实践和研究的热点;软件所扮演的角色日趋关键,高效开发的同时更需要高可靠性的软件。论文所关注的就是针对开发设计阶段的基于构件软件,采用FTA技术,考虑等概率条件下的软件运行剖面,进行面向软件运行的可靠性分析,试图为软件的设计和测试提供更具有实际意义的反馈和指导,进而增强软件的可靠性。文章还介绍了基于这样的技术针对小型的基于构件软件进行的实证分析。     

Multi-faceted quality and defect measurement for web software and source contents

In this paper, we examine external failures and internal faults traceable to web software and source contents. We develop related defect and quality measurements based on different perspectives of customers, users, information or service hosts, maintainers, developers, integrators, and managers. These measurements can help web information and service providers with their quality assessment and improvement activities to meet the quality expectations of their customers and users. The different usages of our measurement framework by different stakeholders of web sites and web applications are also outlined and discussed. The data sources include existing web server logs and statistics reports, defect repositories from web application development and maintenance activities, and source files. We applied our approach to four diverse websites: one educational website, one open source software project website, one online catalog showroom for a small company, and one e-Commerce website for a large company. The results demonstrated the viability and effectiveness of our approach.     

Using the analytic network process (ANP) in a SWOT analysis - A case study for a textile firm

Strengths, Weaknesses, Opportunities and Threats (SWOT) analysis does not provide an analytical means to determine the importance of the identified factors or the ability to assess decision alternatives according to these factors. Although the analysis successfully pinpoints the factors, individual factors are usually described briefly and very generally. For this reason, SWOT analysis possesses deficiencies in the measurement and evaluation steps. Although the analytic hierarchy process (AHP) technique removes these deficiencies, it does not allow for measurement of the possible dependencies among the factors. The AHP method assumes that the factors presented in the hierarchical structure are independent; however, this assumption may be inappropriate in light of certain internal and external environmental effects. Therefore, it is necessary to employ a form of SWOT analysis that measures and takes into account the possible dependency among the factors. This paper demonstrates a process for quantitative SWOT analysis that can be performed even when there is dependence among strategic factors. The proposed algorithm uses the analytic network process (ANP), which allows measurement of the dependency among the strategic factors, as well as AHP, which is based on the independence between the factors. Dependency among the SWOT factors is observed to effect the strategic and sub-factor weights, as well as to change the strategy priorities.     

The analytic network process for managing inter-enterprise collaboration: A case study in a collaborative enterprise network

In the last years, collaboration among enterprises has gained attention in the business environment as a means to remain competitive. Enterprises that are collaborating look for improving their performance but, in real assessments, they often do not establish efficient frameworks to structure and manage the enterprise association/inter-enterprise performance. In addition, there are many factors that act as barriers to effective collaboration and have to be also properly managed as they impact on the inter-enterprise performance. This paper provides a methodology based on the analytic network process (ANP) to identify and measure, under an integrated approach, both factors and inter-enterprise performance considering their reciprocal impact. With this innovative approach, enterprises will obtain significant information for the decision-making process regarding which are the factors and inter-enterprise performance elements that generate a higher impact and therefore have a high priority within the specific collaborative relationship. Thus, enterprises can focus their efforts on improving those most important factors and performance elements, and consequently, enhancing their competitiveness.     

Java-MaC: A Run-Time Assurance Approach for Java Programs

We describe Java-MaC, a prototype implementation of the Monitoring and Checking (MaC) architecture for Java programs. The MaC architecture provides assurance that the target program is running correctly with respect to a formal requirements specification by monitoring and checking the execution of the target program at run-time. MaC bridges the gap between formal verification, which ensures the correctness of a design rather than an implementation, and testing, which does not provide formal guarantees about the correctness of the system.Use of formal requirement specifications in run-time monitoring and checking is the salient aspect of the MaC architecture. MaC is a lightweight formal method solution which works as a viable complement to the current heavyweight formal methods. In addition, analysis processes of the architecture including instrumentation of the target program, monitoring, and checking are performed fully automatically without human direction, which increases the accuracy of the analysis. Another important feature of the architecture is the clear separation between monitoring implementation-dependent low-level behaviors and checking high-level behaviors, which allows the reuse of a high-level requirement specification even when the target program implementation changes. Furthermore, this separation makes the architecture modular and allows the flexibility of incorporating third party tools into the architecture. The paper presents an overview of the MaC architecture and a prototype implementation Java-MaC.     

Inter-rater reliability of output measures for a posture matching assessment approach: a pilot study with food service workers

Despite the ongoing health problem of repetitive strain injuries, there are few tools currently available for ergonomic applications evaluating cumulative loading that have well-documented evidence of reliability and validity. The purpose of this study was to determine the inter-rater reliability of a posture matching based analysis tool (3DMatch, University of Waterloo) for predicting cumulative and peak spinal loads. A total of 30 food service workers were each videotaped for a 1-h period while performing typical work activities and a single work task was randomly selected from each for analysis by two raters. Inter-rater reliability was determined using intraclass correlation coefficients (ICC) model 2,1 and standard errors of measurement for cumulative and peak spinal and shoulder loading variables across all subjects. Overall, 85.5% of variables had moderate to excellent inter-rater reliability, with ICCs ranging from 0.30–0.99 for all cumulative and peak loading variables. 3DMatch was found to be a reliable ergonomic tool when more than one rater is involved.     

A survey of tools for the validation and verification of knowledge-based systems: 1985-1995

This paper presents the findings of a survey of software tools built to assist in the verification and validation of knowledge-based systems. The tools were identified from literature sources from the period 1985-1995. The tool builders were contacted and asked to complete and return a survey that identified which testing and analysis techniques were utilised and covered by their tool. From these survey results it is possible to identify trends in tool development, technique coverage and areas for future research.     

Methodology for evaluating a novel education technology: a case study of handheld video games in Chile

Many school systems, in both the developed and developing world, are implementing educational technology to assist in student learning. However, there is no clear consensus on how to evaluate these new technologies. This paper proposes a comprehensive methodology for estimating the value of a new educational technology in three steps: benefit analysis, through the administration of a well-designed experiment; cost analysis, which incorporates costs to weigh against the benefits; and feasibility analysis, which introduces real-world concerns that may affect the ability to actually implement the technology. To illustrate the methodology, a case study from Chile is used where portable educational video games were introduced into first and second grade classrooms with the aim of improving learning in mathematics and language. This paper demonstrates the importance of all three steps in the evaluation process and provides a framework for future analyses.     

Construction and analysis of ground models and their refinements as a foundation for validating computer-based systems

We explain why for the verified software challenge proposed in Hoare (J ACM 50(1): 63–69, 2003), Hoare and Misra (Verified software: theories, tools, experiments. Vision of a Grand Challenge project. In: [Meyer05]) to gain practical impact, one needs to include rigorous definitions and analysis, prior to code development and comprising both experimental validation and mathematical verification, of ground models, i.e., blueprints that describe the required application-content of programs. This implies the need to link via successive refinements the relevant properties of such high-level models in a traceable and checkable way to code a compiler can verify. We outline the Abstract State Machines (ASM) method, a discipline for reliable system development which allows one to bridge the gap between informal requirements and executable code by combining application-centric experimentally validatable system modelling with mathematically verifiable stepwise detailing of abstract models to compile-time-verifiable code.     

ManufAg: a multi-agent-system framework for production control of complex manufacturing systems

In this paper, we present a framework for the implementation of multi-agent-systems for production control of complex manufacturing systems. We present the results of a requirement analysis for production control systems for complex manufacturing systems; then we describe the framework design criteria. Our framework supports the inclusion of distributed hierarchical decision-making schemes into the production control. Furthermore, in order to increase the coordination abilities of multi-agent-systems, we follow the decision-making and staff agent architecture suggested in the PROSA reference architecture. We indicate the usage of the framework for designing and implementing an agent-based production control system for semiconductor manufacturing processes in a case study.     

A framework for performing workplace hazard and risk analysis: a participative ergonomics approach

Despite the unanimity among researchers about the centrality of workplace analysis based on participatory ergonomics (PE) as a basis for preventive interventions, there is still little agreement about the necessary of a theoretical framework for providing practical guidance. In an effort to develop a conceptual PE framework, the authors, focusing on 20 studies, found five primary dimensions for characterising an analytical structure: (1) extent of workforce involvement; (2) analysis duration; (3) diversity of reporter role types; (4) scope of analysis and (5) supportive information system for analysis management. An ergonomics analysis carried out in a chemical manufacturing plant serves as a case study for evaluating the proposed framework. The study simultaneously demonstrates the five dimensions and evaluates their feasibility. The study showed that managerial leadership was fundamental to the successful implementation of the analysis; that all job holders should participate in analysing their own workplace and simplified reporting methods contributed to a desirable outcome.

Practitioner summary: This paper seeks to clarify the scope of workplace ergonomics analysis by offering a theoretical and structured framework for providing practical advice and guidance. Essential to successfully implementing the analytical framework are managerial involvement, participation of all job holders and simplified reporting methods.     

Systems scenarios: a tool for facilitating the socio-technical design of work systems

Abstract

The socio-technical systems approach to design is well documented. Recognising the benefits of this approach, organisations are increasingly trying to work with systems, rather than their component parts. However, few tools attempt to analyse the complexity inherent in such systems, in ways that generate useful, practical outputs. In this paper, we outline the ‘System Scenarios Tool’ (SST), which is a novel, applied methodology that can be used by designers, end-users, consultants or researchers to help design or re-design work systems. The paper introduces the SST using examples of its application, and describes the potential benefits of its use, before reflecting on its limitations. Finally, we discuss potential opportunities for the tool, and describe sets of circumstances in which it might be used.

Practitioner Summary: The paper presents a novel, applied methodological tool, named the ‘Systems Scenarios Tool’. We believe this tool can be used as a point of reference by designers, end-users, consultants or researchers, to help design or re-design work systems. Included in the paper are two worked examples, demonstrating the tool’s application.     

Active construction of experience through mobile media: a field study with implications for recording and sharing

To fully appreciate the opportunities provided by interactive and ubiquitous multimedia to record and share experiences, we report on an ethnographic investigation on the settings and nature of human memory and experience at a large-scale event. We studied two groups of spectators at a FIA World Rally Championship in Finland, both equipped with multimedia mobile phones. Our analysis of the organization of experience-related activities in the mass event focuses on the active role of technology-mediated memories in constructing experiences. Continuity, reflexivity with regard to the Self and the group, maintaining and re-creating group identity, protagonism and active spectatorship were important social aspects of the experience and were directly reflected in how multimedia was used. Particularly, we witnessed multimedia-mediated forms of expression, such as staging, competition, storytelling, joking, communicating presence, and portraying others; and the motivation for these stemmed from the engaging, processual, and shared nature of experience. Moreover, we observed how temporality and spatiality provided a platform for constructing experiences. The analysis advocates applications that not only store or capture human experience for sharing or later use but also actively participates in the very construction of experience. The approach conveys several valuable design implications.

A modified failure mode and effects analysis method for supplier selection problems in the supply chain risk environment: A case study

In the emerging supply chain environment, supply chain risk management plays a more important role than ever. Companies must focus not only on the efficiency of supply chain, but also on its risks. If an unanticipated event occurs, all of the supply chain members will be impacted, and the result will cause significant loss. Therefore, this research proposes a modified failure mode and effects analysis (MFMEA) method to select new suppliers from the supply chain risk’s perspective and applies the analytic hierarchy process (AHP) method to determine the weight of each criterion and sub-criterion for supplier selection. An IC assembly company is then studied to validate this model. The result shows that the case company can categorize its suppliers more effectively and at the same time select a low-risk supply chain partner. Moreover, the case company can provide unsatisfactory suppliers with valuable feedback that will help them improve and become its partners in the future.     

Development and integration of a concurrently executing interactive user interface for the I-STAT protable clinical analyzer: A case study in real-time systems integration

A novel real-time scheduler was developed to implement an interactive user interface for an existing state-of-the-art, hand-held blood analyzer. A software-timer-based scheduler was designed and implemented and guaranteed schedulability analysis performed to ensure that all hard execution deadlines could be met at run time. An execution bandwidth preservation mechanism that increases the robustness and predictability of the scheduler is presented. The paper is a case study that describes the design and development process from a point of view that emphasizes the importance of the systems integration issues that were encountered.