Combined hardware and software aspects of reliability

This paper presents the similarities and differences between hardware, software and system reliability. Relative contributions to system failures are shown for software and hardware and failure and recovery propensities are also discussed. Reliability, availability and maintainability (RAM) concepts have been broadly developed for software reliability than hardware reliability. Extending these software concepts to hardware and system reliability helps in examining the reliability of complex systems. The paper concludes with assurance techniques for defending against faults. Most of the techniques discussed originate in software reliability but apply to all aspects of a system. Also, the effects of redundancy on overall system availability are shown.     

基于双口RAM的智能429总线接口卡设计

利用89C52单片机和双口RAM IDT7132设计了智能ARINC429总线接口卡。采用单片机使接口卡具有了自动数据处理能力,实现了智能化;采取双口RAM作为单片机和ISA总线数据交互媒介,提高了传输速率。讨论了双口RAM的地址空间分配和数据共享冲突仲裁问题,对接口卡的软件设计做了介绍。应用表明,所设计的接口卡具有传输速率高、可靠性好等优点。     

双口RAM在声信号处理数据接口模块中的应用

介绍了双口RAM器件在数据接口模块的软硬件设计中的应用实例。该模块选用了VME总线方式,主要器件选用了具有强大运算能力的DSP芯片和存储能力极其方便的双口RAM器件,还有差分接口模块和DC/DC电压转换器等。重点介绍了双口RAM CY7C026-25AI的结构特点及其有趣的＂乒乓＂工作方式,分析了双口RAM与FIFO以及普通存储器的性能差异,对以往SHARC处理器和FIFO芯片的配合方式提出新的观点,即SHARC处理器和双口RAM的组合方式,展示了双口RAM器件在现代数据采集设备中使用的绝对优势。     

Development and application of a Risk Assessment Tool

Probabilistic Safety Assessment (PSA) is a powerful method for evaluating the safety of nuclear facilities. PSA models are the basis of risk monitors, which can be utilized for monitoring the plant risk. The objective of this work was to develop a risk monitoring software tool, which could match the requirements for a risk monitor, according to standard reference documents. We tried to implement all required features in a user-friendly interface. In this paper a newly developed risk monitor called Risk Assessment Tool (RAT) is presented, and its main features and capabilities are introduced. Some of these features are: graphical event/fault tree developing interface, a 30-day risk profile, performing importance analysis, different administrative levels, and handling time-dependent failure data. In order to have an actual application, a case study is performed for Tehran Research Reactor, and the results are compared to the results obtained from a well-known reliability software package. In most cases, the results from two software tools match well.     

A Statistical Approach for Improving the Performance of a Testing Methodology for Measurement Software

This paper describes the significant enhancements brought to an original methodology designed for testing measurement software. In a previous paper, the authors proposed a black-box seven-step procedure that allows the functional verification of complex instrument software to be performed. The main features of the procedure are concerned with the following: (1) the ability of reproducing actual correlations among the software inputs and (2) the need for a limited number of test cases. Making use of innovative statistical techniques, the methodology performance and reliability have been enhanced. Two further steps have been added with the aim of improving the correlation coefficient assessments and providing the estimations with a confidence level. Finally, a new strategy has been studied to optimize the number of test cases. The effects of the new solutions on the performance of the methodology are evaluated by applying the procedure to a complex software module employed in an automotive system. A comparison with the previous methodology version is also reported.     

双口RAM在嵌入式多CPU系统中的应用

结合对控制系统可靠性、实时性以及资源共享的研究,阐述了双口RAM在嵌入式多CPU系统中的应用特色和关键技术;提出用双口RAM实现多CPU之间高速、可靠的并行数据通信和数据共享,可使整个系统软硬件设计简单方便,资源充分利用,可靠性和实时性也都比较高;给出一个双口RAM在嵌入式多CPU系统中的具体应用实例,证实了基于双口RAM的嵌入式多CPU系统有着强大的性能;将它与通用的工控机进行比较,展现了基于双口RAM的嵌入式多CPU系统的广阔应用前景.     

Key attributes of the SAPHIRE risk and reliability analysis software for risk-informed probabilistic applications

The Idaho National Laboratory is a primary developer of probabilistic risk and reliability analysis (PRRA) tools, dating back over 35 years. Evolving from mainframe-based software, the current state-of-the-practice has led to the creation of the SAPHIRE software. Currently, agencies such as the Nuclear Regulatory Commission, the National Aeronautics and Aerospace Agency, the Department of Energy, and the Department of Defense use version 7 of the SAPHIRE software for many of their risk-informed activities. In order to better understand and appreciate the power of software as part of risk-informed applications, we need to recall that our current analysis methods and solution methods have built upon pioneering work done 30–40 years ago. We contrast this work with the current capabilities in the SAPHIRE analysis package. As part of this discussion, we provide information for both the typical features and special analysis capabilities, which are available. We also present the application and results typically found with state-of-the-practice PRRA models. By providing both a high-level and detailed look at the SAPHIRE software, we give a snapshot in time for the current use of software tools in a risk-informed decision arena.     

纸质托盘结构设计软件的开发

目的研究物流运输包装中托盘结构设计软件开发的方法。方法利用AutoCAD的二次开发工具,结合VBA面向对象编程的强大功能,通过分析纸质托盘的类型、形状和标准托盘的主要尺寸关系,将DVB程序进行自动加载后,实现纸质托盘的参数化设计、效果图的显示及尺寸标注等主要功能。结果此设计软件具有良好的人机交互界面,通过选择托盘类型及输入关键尺寸,即可获得用于加工制造的平面尺寸图,并可根据客户需求实现纸质托盘的自主设计,具有更大的灵活性。结论该软件在纸质托盘的设计和使用上发挥了一定的作用,该设计方法在产品结构设计软件的开发方面具有推广应用价值。     

A Software Tool for Reliability Estimation

Over the years, several tools have been developed to estimate the reliability of hardware and software components. Typically, such tools are either for hardware or software. This paper presents the Software Tool for Reliability Estimation (STORE), which can be used for systems containing hardware and/or software components. For software components, exponential, Weibull, gamma, power, geometric, and inverse-linear models were implemented. Goodness of fit statistics are provided for each model. The user can select the most appropriate model for a given system configuration and failure data. The STORE program can analyze series, parallel, and complex systems. Tieset and cutset algorithm is utilized to determine the reliability of a complex system. The paper presents several examples to demonstrate the software tool.     

Reliability,Availability and Maintainability Analysis of Industrial Systems Using PSO and Fuzzy Methodology

The purpose of this paper is to present a methodology for analyzing the system performance of an industrial system by utilizing uncertain data. Although there have been tremendous advances in the art and science of system evaluation, yet it is very difficult to assess their performance with a very high accuracy or precision. For handling of these uncertainties, fuzzy set theory has been used in the analysis while their corresponding membership functions are generated by solving a nonlinear optimization problem with particle swarm optimization. For finding the critical component of the system which affects the system performance mostly, a composite measure of reliability, availability and maintainability (RAM) named as the RAM-index has been introduced which influences the effects of failure and repair rate parameters on its performance. A time varying failure and repair rate parameters are used in the analysis instead of constant rate models. Finally, the computed results are finally compared with existing methodologies. The suggested framework has been illustrated with the help of a case.     

Key performance indicators for assessing inherent energy performance of machine tools in industries

Increasing attention has been paid toward enhancing energy retrofitting in machine tools due to its enormous energy consumption and high energy-saving potential. Developing energy-efficient machine tools and selecting appropriate machine tools in procurement processes are two effective approaches for saving energy. However, existing studies on the evaluation of energy performance to support the design and selection of machine tools, rarely consider various process controls, which have considerable impact on the energy performance of machine tools. This study proposes a group of key performance indicators, which are referred to as ‘inherent energy performance’ (IEP) indexes, to support the design and selection of machine tools with the consideration of the main process controls in the usage phase and their interaction. A systematic method is introduced to acquire the IEP indexes. The method involves a simplified measurement of basic data and the calculation of the indexes from the data. A case study indicates that the proposed indicators succeed in obtaining the energy demand information of almost all machine system activities and can be used to provide basic data for developing energy information labels, selecting matching machine tools, and designing energy-efficient machine tools.     

The PDS-XADS reference accelerator and its radioprotection issues

At the start-up of the FP5 project PDS-XADS, the main initial specifications for the accelerator system (e.g. beam energy, beam intensity, beam profile, their stability and the accelerator availability and reliability) have been defined by Working Package 1 (WP1), 'Global Coherence', in connection with the other WPs of the project. From this, WP3 ('The Accelerator') has assessed the main requirements and the corresponding technical answers. A reference solution, based on a linear superconducting accelerator with its associated doubly achromatic beam line has been worked out to some detail. For high reliability, the proposed design is intrinsically fault tolerant, relying on highly modular 'de-rated' components associated with a fast digital feedback system. The proposed solution also appears to be robust in terms of operational aspects like maintenance and radioprotection. A programme for the remaining R&D required has been elaborated and is proposed within the FP6 project EUROTRANS.     

Prediction of solidification behaviour and microstructure of Ni based alloys obtained by casting and direct additive laser growth

Numerical tools are now used widely in the prediction of material properties necessary in order to gain a better understanding of the relationship between material properties and performance, to improve the reliability of processes and the quality of the final product, and to reduce costs, waste and energy use. In this paper, the solidification properties and the microstructure of some commercial Ni based alloys were analysed and predicted numerically using the ProCAST software. The microstructure of a sample obtained by the direct additive laser growth, a new additive manufacturing technique based on the selective laser melting, is presented and discussed. Numerical approaches and software packages that can be used to model additive manufacturing processes are discussed and critically analysed.     

Contact geometry estimation and precise radial force prediction for the radial-axial ring rolling process

In the present research work, the modular parametric design plug-in Grasshopper, available in Rhinoceros 5, is utilized as a pre-processor for the estimation of the projection of the contact length between ring and tools in the radial-axial ring rolling process. The estimated lengths, for each round of the process, are then used in a slip line based force model for the precise estimation of the radial forming force. The proposed method allows reducing the inaccuracies of the traditional approaches since it supersedes the concept of common thickness draft on both mandrel and main roll side, allowing a more precise estimation of the projection of the contact arc between ring and tools, considered to have a unique value on both mandrel side and main roll side. The fulfillment of this last assumption ensures the forming force to have the same value regardless it is calculated on the mandrel side or on the main roll side. The model has been validated by cross-comparing the analytical results with those of laboratory experiment and finite element simulation. The developed analytical model has been also applied to three different study cases where the previous literature models for the calculation of the projection of the contact arc have shown inaccuracies, demonstrating that the proposed approach can overcome these limitations. The positive cross comparisons among laboratory experiment, FEM simulations, and analytical estimations prove the reliability of the proposed approach, as well as its good integration with authors’ previous analytical algorithms.     

Economic Impact of Software Patching and Optimal Release Scheduling

Because of highly distributed nature of software products, the task of improving software reliability is becoming a complex job. Specialized tools and techniques are being used to isolate the risky software modules. In order to retain in market, firms are required not only to provide the software on time but also to endow with continuous processing. Product updating is the process that comes to safeguard the firm's image at this point of time. And one such attribute of updating is providing software patches. Today, almost all software firms are providing either patching, module exchange or service pack application processes consequent to a release. This paper proposes a scheduling policy for a software product and shows the importance of patching in lowering the system outages and making the system more cost effective. Validation on the proposed policy has been done using real life software failure data set of Tandem Computers. Copyright © 2016 John Wiley & Sons, Ltd.     

Computer simulation for quality and reliability engineering

Computer simulation has been used widely in many industries for many applications. A simulation model mimics a real world system, enabling an investigation of its operation. More recently simulation models have incorporated a visual display and interactive features to aid understanding and enhance the investigation. Computer simulation has many potential uses in quality and reliability engineering, for instance, modelling equipment failures, quality control strategies, maintenance requirements and operational logistics. A case study shows how simulation has been used to study the throughput, flexibility and robustness of a manufacturing plant design. Alternative simulation software packages are briefly discussed.     

A gamma-ray spectrometer system for fusion applications

A NaI scintillator spectrometer system for the measurement of gamma-ray spectra in tokamak discharges has been developed and installed on the Frascati Tokamak Upgrade. Two NaI scintillators are viewing the plasma at two different angles with respect to the equatorial plane. The main features of the spectrometer system (energy range: 0.3–23 MeV) and of the unfolding technique used to restore physical spectra from the pulse-height distributions are described: a method of solution with regularisation for matrix equations of large size, allowing to process count distributions with significant statistical noise, has been developed. A dedicated software, portable to any platform, has been written both for the acquisition and the analysis of the spectra. The typical gamma-ray spectra recorded in hydrogen and deuterium discharges, also with additional heating, are presented and discussed; two components have been observed: (a) thick-target bremsstrahlung gamma-rays produced by runaway electrons hitting the inconel poloidal limiter and/or the vessel; and (b) neutron capture gamma-rays generated in the detector shielding and tokamak structures. The maximum energy resulting from the bremsstrahlung spectra is in agreement with the runaway energy predicted by a test particle model of runaway electron dynamics.     

What's new in reliability engineering?

Reliability engineering is responding to the trend to computer-aided design (CAD), and the current emphasis on improving competitiveness through quality. Islands of automation addressing reliability for both hardware design and software engineering exist which are not yet connected, though government–industry teams are developing integrated software packages of reliability (and maintainability) tools. TQM (total quality management) principles are being adopted in many industries, and the U.S. Qualified Manufacturers List (QML) programme, which requires qualification of a process rather than a product, is now used for procuring microcircuits. However, government regulations remain a barrier to creating a ‘quality culture’. ISO 9000 is seen by industry as a requirement for international competitiveness, but criticized by some as counterproductive. Research and development of reliability engineering tools reflect the need for implementation in CAD frameworks, and fuzzy logic analysis has attracted the attention of the theorists.