Optimal design for software reliability and development cost

A process for reliability-related quality programming is developed to fill existing gaps in software design and development so that a quality programming plan can be achieved. The tradeoffs among system reliability improvement, resource consumption, and other relevant constraints through the management phase are investigated. A software reliability-to-cost relation is developed both from a software reliability-related cost model and from software redundancy models with common-cause failures. A generic N-component redundancy model is also developed. The software reliability optimization problems can be formulated into a mixed-integer programming problem     

A testing-effort dependent software reliability model and its application

We discuss a software reliability growth model with testing-effort based on a nonhomogeneous Poisson process and its application to a testing-effort control problem. The time-dependent behaviour of testing-effort expenditures which is incorporated into software reliability growth is expressed by a Weibull curve due to the flexibility in describing a number of testing-effort expenditure patterns. Using several sets of actual software error data, the model fitting and examples of a testing-effort control problem are illustrated.     

Optimal software release policies for a non-homogeneous software error detection rate model

Optimal software release policies, which decide when to stop testing a software system and transfer it to the user, are discussed for a software reliability growth model with nonhomogeneous error detection rate. Two evaluation criteria, i.e. total expected software cost and software reliability, are introduced. The optimal software release policies respectively derived for each criterion and those simultaneously evaluating both criteria are discussed. Numerical examples on those optimal software release policies are presented for illustration.     

Optimal software release policy with a learning factor for imperfect debugging

In this paper, we discuss a software reliability growth model with a learning factor for imperfect debugging based on a non-homogeneous Poisson process (NHPP). Parameters used in the model are estimated. An optimal release policy is obtained for a software system based on the total mean profit and reliability criteria. A random software life-cycle is also incorporated in the discussion. Numerical results are presented in the final section.     

Application of a software reliability model to decide software release time

In this paper, using a Binomial reliability model, we formulate the optimal software release time problem as a probabilistic dynamic programming. Using some properties of the cost functions associated with this problem, we develop an efficient algorithm to obtain the optimal release time decision.     

Optimization models for selection of programs, considering cost andreliability

The authors present two optimization models for decision support tools for selecting available programs in the market. Information on reliability and cost of the available programs are considered as basic criteria for the selection. These models apply to software packages that consist of several programs where each, upon execution, performs a different function as required by the user. The objective is to maximize the average reliability of the software package, considering the tradeoff between reliability and cost of the programs. In model one, redundancy of the programs is not considered; thus, the authors select one program for each function. In model two, redundancy is considered: thus, the authors identify the optimal set of programs for each function. They begin with a discussion of the underlying concepts that rationalize the composition of the models     

Optimal burn-in for minimizing cost and multiobjectives

In general, a small proportion of components will be weak because of some imperfection in the control of the production process or in the design of the components. This paper discusses an optimal burn-in procedure to minimize total costs based on the assumption that some of the components are weak and deteriorate faster than the strong components. The procedure will define the costs of burn-in errors. In practice, it may be impossible to eliminate all weak components through burn-in due to a nonzero proportion of defectives of the components. Therefore, burn-in errors could occur for some reasons. Probability models and cost models are formulated to find the optimal burn-in time that minimizes the expected total cost. An example is included to show how to use the results. Finally, multiobjective optimal burn-in for series systems is presented using the surrogate worth trade-off method.     

Needed resources for software module test, using thehyper-geometric software reliability growth model

Considerable testing resources are required during software module testing. This paper, based on the `hyper-geometric distribution software reliability growth model' (HGDM) investigates two optimal resource allocation (OPT/RA) problems in software module testing: (1) minimization of the number of software faults (NSF) still undetected in the system after testing, given a fixed amount of testing resources; and (2) minimization of the total amount of testing resources required, given the NSF still undetected in the system after testing. Based on the concepts of average allocation and proportional allocation, two simple allocation methods are introduced. Experimental results show that the OPT/RA method can improve the quality and reliability of the software system much more than the simple allocation methods. Therefore, the OPT/RA method is very efficient for solving the `testing resource allocation' problem     

Maintenance of reliable real time systems: Hardware versus software tradeoffs

The maintenance features in a high reliability real time control system form an important component in the total system. It is essential that software and hardware maintenance features function in an effective manner to ensure a high level of reliability in real time systems. Hardware maintenance features include redundant processors, self-checking circuits, diagnostic microcode etc., while software maintenance features include fault recovery programmes, audits, diagnostics etc. In this paper, we examine briefly the relationship of maintenance software to hardware in current high reliability real time systems, and how this relationship is likely to change in the future. Discussion in the paper centres around issues such as: factors that contribute to effective maintenance design; hardware characteristics that affect software; partitioning of maintenance functions between software, firmware and hardware; and current trends in maintenance of real time systems.     

硬盘测试软件设计与测试

硬盘作为计算机中存储数据的主要载体,其性能的好坏直接决定着整个计算机系统性能的高低.本文设计实现了一种硬盘测试软件,主要模拟硬盘实际I/O读写情况,发出读操作命令,然后统计、计算测试过程中的各个参数指标值.测试的性能参数包括：瞬时、平均、最大数据传速率,平均、最大读操作响应时间,读操作次数,读错误次数及CPU占用率等.分析测试结果知,在硬盘基本性能参数测试时,顺序读操作测试的硬盘瞬时数据传输率随着读操作数据块的增加先增大后减小;随机读操作比相应数据块大小的顺序读操作的数据传输率小.模拟测试流媒体文件服务时,多用户的总数据传输率比单用户时的数据传输率要小得多.     

Executive systems and software development for minicomputers

This paper presents a tutorial survey of the function and construction of executive systems for minicomputers. A modular approach to the construction of device schedulers, swapping and multiprogramming supervisors, and file systems is emphasized. Considerable use is made of programming technology borrowed from large-scale computer systems, but specialized to the needs of small-scale minicomputer systems. The paper also describes the use of high-level languages, structured programming, and program-development systems in the application of this technology to the minicomputer environment.     

电子政务的安全、效率、成本

电子政务建设中的网络安全,是一个值得高度关注的问题,也是容易引起争议的焦点。在电子政务建设中,如果信息安全失去保障,其后果是不堪设想的。但是如果一味地强调安全而忽视对政府信息资源的充分公开,必然对电子政务的应用造成许多人为的障碍,降低了其应用效率,电子政务的价值也随之大打折扣。     

Optimal, suboptimal, and adaptive threshold policies for power efficiency of wireless networks

We prove that for any modulation, demodulation, and coding schemes and under general assumptions on the wireless channel model, the optimal power-efficient policy for transmit power assignment is necessarily of threshold nature. Although detailed features of this policy are quite complicated, it admits a simple and practical suboptimal version. Since both the optimal and suboptimal policies may have poor location-fairness characteristics, we introduce novel performance metrics (e.g., the average downtime and uptime), which quantify the short-term behavior of these policies, and develop analytical methods for their evaluation. Using these methods, we show that, although threshold policies may be extremely power efficient, users in poor locations relative to the base station may have unacceptable short-term performance characteristics. To alleviate this deficiency, we introduce an adaptive threshold policy, in which the threshold is adjusted to the user's location, and show that it is both relatively power efficient and location fair.     

探索式软件测试方法分析

本文将从探索式软件测试的定义、思维模式和特点上进行阐述,论述如何制定优质的探索章程以及探索式软件测试的应用和未来前景。     

系统体系方法与软件系统功能形式分解

从系统体系理论和方法出发,研究基于物联网、云计算的开放应用软件系统功能分解的描述和评价方法,提出用功能框架方法对系统从抽象到具体进行描述对于系统体系的重要性.提出从抽象出发的适应软件系统体系建立的功能分解方法和功能评估方法,并说明这些方法在系统开发以及建立系统稳定中间形式中的作用,这有助于在物联网、云计算和SOA等开放环境下的大型应用软件系统的建设、部署和维护过程的改进.     

Propagation-prediction and site-planning software for wireless communication systems

Propagation-prediction and site-planning software for wireless communication networks has been developed. The software has a user-friendly graphical user interface (GUI), and provides calculations for large-scale and small-scale propagation parameters, including path loss (or received power) and delay profiles. Angles of arrival/departure, which are useful for the design of wireless systems employing multiple antennas, are also provided in the simulation. Some of the main features of the software include the use of a computationally efficient ray-tracing approach for simulating propagation in wireless environments, and the fact that users can upload AutoCAD .dxf files for indoor or outdoor environments. Both a single-building floor plan or an entire city layout can be simulated, and the user is provided with the ability to assign wall geometries and electrical parameters. User-defined realistic antenna radiation patterns for both the transmitting and receiving antennas are incorporated in the simulation. Broadband as well as polarization-dependent simulations are also included in the software.     

Partitioning and pipelining for performance-constrainedhardware/software systems

In order to satisfy cost and performance requirements, digital signal processing and telecommunication systems are generally implemented with a combination of different components, from custom-designed chips to off-the-shelf processors. These components vary in their area, performance, programmability and so on, and the system functionality is partitioned amongst the components to best utilize this tradeoff. However, for performance critical designs, it is not sufficient to only implement the critical sections as custom-designed high-performance hardware, but it is also necessary to pipeline the system at several levels of granularity. We present a design flow and an algorithm to first allocate software and hardware components, and then partition and pipeline a throughput-constrained specification amongst the selected components. This is performed to best satisfy the throughput constraint at minimal application-specific integrated-circuit cost. Our ability to incorporate partitioning with pipelining at several levels of granularity enables us to attain high throughput designs, and also distinguishes this paper from previously proposed hardware/software partitioning algorithms     

Optimal filtering for multirate systems

For a multirate system where the output sampling is slower than the input updating, this brief aims at designing filters for fast state estimation in the H/sub 2/ and H/sub /spl infin// settings. Because of the multirate nature, linear matrix inequality solutions to the design problems involve a nonconvex constraint, which is numerically tackled by the product reduction algorithm. Finally, a design example is given and the effectiveness of the approach is illustrated.     

Optimal testing resource allocation, and sensitivity analysis in software development

We consider two kinds of software testing-resource allocation problems. The first problem is to minimize the number of remaining faults given a fixed amount of testing-effort, and a reliability objective. The second problem is to minimize the amount of testing-effort given the number of remaining faults, and a reliability objective. We have proposed several strategies for module testing to help software project managers solve these problems, and make the best decisions. We provide several systematic solutions based on a nonhomogeneous Poisson process model, allowing systematic allocation of a specified amount of testing-resource expenditures for each software module under some constraints. We describe several numerical examples on the optimal testing-resource allocation problems to show applications & impacts of the proposed strategies during module testing. Experimental results indicate the advantages of the approaches we proposed in guiding software engineers & project managers toward best testing resource allocation in practice. Finally, an extensive sensitivity analysis is presented to investigate the effects of various principal parameters on the optimization problem of testing-resource allocation. The results can help us know which parameters have the most significant influence, and the changes of optimal testing-effort expenditures affected by the variations of fault detection rate & expected initial faults.