Rethinking Components: From Hardware and Software to Systems

The germ of the component idea arose in mass production as the interchangeable part, but in today's information and communications technology (ICT) industries the component can connote considerably more, such as multiple uses, opportunistic combinations with other components, design by assembly, and incremental evolution through field replacement with upgraded components. In spite of its many advantages, the component has failed to keep up with increasing scales of integration, increasing use of software, and the resulting complexity and application diversity. A rethinking of the component and associated industry practices is needed in light of modern technology and applications. Componentization has many payoffs, including as a process for industry coordination, most notably in large multivendor complex systems with fragmented administrative and ownership domains. Invigorating componentization requires abandoning antiquated concepts such as components are exclusively hardware or software or even exclusively technological, are units of manufacture and packaging, or that each component is the responsibility of an individual firm. The system component, which incorporates hardware, software, and oftentimes even human process or organizational elements, whatever is necessary to achieve a coherent body of functionality, is the appropriate perspective today.     

Personal Computer Communications Via Telephone Facilities

Communication from terminals to other terminals and to computing service systems has been an important aspect of data communications since the early 1960's. When personal computers arrived on the scene, in the 1970's, the use of telephone facilities and modems for communications was a natural extension of existing technology. Now, however, many modems have "intelligence" and can be controlled from their electrical interface, communication software is available to facilitate the use of a modem and coordinate the communication process, and there are many uses for personal computer communications. Some of the hardware, software, and computing services for personal computer communications are discussed in this paper.     

Software Structure of No. 5 ESS--A Distributed Telephone Switching System

Most stored program controlled telephone switching systems are designed with centralized control architectures. Evolving processor technology and requirements of smooth growth over a wide size range have led system designers to take advantage of distributed processing architectures. This paper provides a conceptual framework for software partitioning on a distributed stored-program controlled switching system and discusses the resulting software structure as present in No. 5 ESS. To facilitate the software development process, a methodology based on current software engineering principles is employed. Sufficiently decoupled software components have expedited parallel development of software and provided reliability by reducing interaction and limiting propagation of errors among software components. The structuring strategy described for telephone switching is equally applicable to other distributed real-time control systems.     

大型系留气球测控系统软件设计

大型系留气球长时间滞空的特点,决定测控系统的稳定和可靠工作非常重要。根据大型系留气球测控系统的组成与软件体系结构,提出球上测控软件（包括初始化、通信处理、数据处理、气球控制、通信电台控制和应急处理）、地面显控软件的设计要点。工程实践表明,双路冗余设计是增强大型系留气球测控系统可靠性的有效手段。     

实测数据参数拟合的红外大气透过率仿真

计算红外大气透过率的常规方法主要有经验公式法和专业软件计算法,前者存在较大的误差,后者的计算过程复杂且对红外仿真系统的移植和兼容困难,因此,本文基于具体地区多年实测大气数据,利用分子的单线吸收法计算不同温度下的水蒸气和二氧化碳的吸收系数;然后,对不同高度分布的温度、压强以及气溶胶后向散射系数的解析式进行分月拟合。在此基础上,实现红外辐射大气透过率的仿真建模。仿真结果与主流专业软件MODTRAN自定义模式下的精确计算结果很接近,而且本方法使用简单、移植性强,在工程应用上具有一定的参考价值。     

On conceptual design of intelligent mechatronic systems

We have technology now to design networks of small intelligent units capable of competing and/or co-operating with each other on specified tasks and making decisions under conditions of uncertainty through a process of negotiation. In highly dynamic environments, such distributed systems are capable of achieving considerably better results in terms of performance/cost ratio and reliability than conventional centralised large systems and structures. The major elements of these systems are intelligent agents, which are software objects capable of communicating with each other, as well as reasoning about received messages. The paper discusses conceptual design of mechatronic systems based on multi-agent technology.     

CELL/B.E.的高性能维特比译码

Viterbi decoding is widely used in many radio systems. Because of the large computation complexity, it is usually implemented with ASIC chips, FPGA chips, or optimized hardware accelerators. With the rapid development of the multicore technology, multicore platforms become a reasonable choice for software radio （SR） systems. The Cell Broadband Engine processor is a state-of-art multi-core processor designed by Sony, Toshiba, and IBM. In this paper, we present a 64-state soft input Viterbi decoder for WiMAX SR Baseband system based on the Cell processor. With one Synergistic Processor Element （SPE） of a Cell Processor running at 3.2GHz, our Viterbi decoder can achieve the throughput up to 30Mb/s to decode the tail-biting convolutional code. The performance demonstrates that the proposed Viterbi decoding implementation is very efficient. Moreover, the Viterbi decoder can be easily integrated to the SR system and can provide a highly integrated SR solution. The optimization methodology in this module design can be extended to other modules on Cell platform.     

The Impact of Modeling Formalisms on Software Maintenance

Maintenance consumes the majority of software's lifecycle resources. Factors affecting the maintenance phase are of practical concern to systems developers and users, but only a few of those factors are under direct control of the project manager. Modeling formalisms are generally touted for their impacts on the development of software; however their impact on maintenance is less discussed and less clear. The question addressed in this research is what impact the choice of modeling formalism has on system maintenance activity. Modeling formalisms are used to capture, analyze and present systems. Major modeling formalisms include process, data, and object-oriented (OO). While process and data formalisms tend to focus more on system processes or data respectively, OO is intended to more evenly balance the treatment of both. Sixty organizations provided data on the use of modeling formalisms across the organization and data on 112 software development projects. The results show how the choice of a modeling formalism has significant differential implications for software maintenance. Despite other research results to the contrary, the results reported here lead us to the conclusion that the choice of an OO modeling formalism had the best impact on maintenance     

The LOFAR Telescope: System Architecture and Signal Processing

The low frequency array (LOFAR) is a large distributed radio telescope, consisting of phased array antenna stations that are combined in an aperture synthesis array. Antenna stations consist of many simple, omnidirectional antennas. Flexible station-based signal processing allows for trading bandwidth against instantaneous sky coverage. Central processing implements a software correlator, which can be reconfigured as a full tied array beamformer, and online calibration functions to handle the large data streams produced by the system. The key science programs for LOFAR challenge the technical specifications in several directions, which resulted in a highly reconfigurable architecture. This paper describes the LOFAR system design, the configuration, and the signal-processing chain. LOFAR has been developed by ASTRON and a consortium of universities and industrial partners. The instrument is currently being deployed in The Netherlands. Additional stations are being built in several other European countries. The telescope is considered an important pathfinder for the square kilometer array (SKA) in demonstrating the potential of (sparse) aperture arrays, in developing solutions to major calibration issues that are directly applicable to the SKA, and in paving the way for the mass-production and operations of such large distributed radio telescope systems.     

Versatile clinical information system design for emergency departments.

Compared to other hospital units, the emergency department presents some distinguishing characteristics of its own. Emergency health-care delivery is a collaborative process involving the contribution of several individuals who accomplish their tasks while working autonomously under pressure and sometimes with limited resources. Effective computerization of the emergency department information system presents a real challenge due to the complexity of the scenario. Current computerized support suffers from several problems, including inadequate data models, clumsy user interfaces, and poor integration with other clinical information systems. To tackle such complexity, we propose an approach combining three points of view, namely the transactions (in and out of the department), the (mono and multi) user interfaces and data management. Unlike current systems, we pay particular attention to the user-friendliness and versatility of our system. This means that intuitive user interfaces have been conceived and specific software modeling methodologies have been applied to provide our system with the flexibility and adaptability necessary for the individual and group coordinated tasks. Our approach has been implemented by prototyping a web-based, multiplatform, multiuser, and versatile clinical information system built upon multitier software architecture, using the Java programming language.     

基于随机Petri网模型的多DSP系统性能分析

多处理器并行处理系统在许多领域都有广泛的应用,然而由于存在系统体系结构、通信带宽和软件并行性等诸多因素的影响,往往会很大程度上制约多处理器系统性能的发挥,因此有效的评估多处理器并行处理系统的性能是系统设计阶段必不可少的任务之一。本文以ADSP14060为核心的多DSP并行处理系统的结构特征,分析了＂主从＂并行结构和＂流水线＂结构的特点;在系统结构分析的基础上,分别建立了基于广义随机Petri网的多DSP并行处理系统模型,并应用该系统模型对＂主从＂结构和＂流水线＂结构的性能进行了全面的评估,找到影响系统性能的各种因素和提高系统性能的办法。     

Pervasive grid for large-scale power systems contingency analysis

Optimal control and management of power systems require extensive analyses of phenomena that can compromise their operation in order to evaluate their impact on the security and reliability levels of the electrical networks. For complex networks, this process, known as power systems contingencies analysis, requires large computational efforts, whereas computation times should be less than a few minutes for the information to be useful. Even though many architectures based on conventional parallel and distributed systems have been widely proposed in the literature, they are characterized by low extensibility, reusability, and scalability, and so, they require a sensible hardware upgrade when more computational resources are necessary. This event is not infrequent in power systems where the constant growth of the electrical network complexity and the need for larger security and reliability levels of the plant infrastructures lead to the need of more detailed contingency analysis in shorter times. To address this problem, this paper proposes a pervasive grid approach to define a user-friendly software infrastructure for data acquisition from electrical networks and for data processing in order to simulate possible contingencies in a real electrical network. The grid infrastructure adopts a brokering service, based on an economy-driven model, to satisfy the quality of service constraints specified by the user (i.e., a time deadline to simulate the contingencies). This paper also discusses the deployment of the infrastructure on a network of heterogeneous clusters and PCs to compute the contingency analysis of a realistic electrical network. The experimental results obtained demonstrate the effectiveness of the proposed solution and the potential role of grid computing in supporting intensive computations in power systems.     

基于nRF2401芯片的无线数据通信

介绍了工作于2．4GHzIsM频段的射频收发芯片nRF2401的主要特性、工作模式以及配置字。设计了＋5V单片机AT89C52与nRF2401芯片的硬件接口电路,解决电平转换的问题,实现了数据的双向传输。给出了软件控制过程和调试结果,该设计实现的无线数据通信可靠稳定,传输速率高,可应用于各种无线通信系统中。     

Models for storing and presenting multimedia documents

This paper deals with models for storing and presenting multimedia documents integrating large amounts of data of different types. Usually, multimedia systems integrate a variety of data such as voice, graphics, text video and other types of images into a single document. Most of these data are not structured and therefore require a huge storage capacity. Such a requirement causes many problems for traditional database management systems which were not originally designed to manipulate data other than text. The presentation of multimedia documents incorporates documentary research that depends upon storage model and mechanisms. In this paper, we present two data storage models and several other associated models for the presentation of multimedia documents. The analysis of these models reveals their capacity to synchronize various temporal scenarios while allowing users simultaneous and secure access to multimedia systems.     

基于FPGA的嵌入式视频采集系统设计

随着数字技术的飞速发展,视频采集与处理技术在众多领域有着越来越广泛的应用。当前市场上已出现多种视频采集卡,但由于视频数据量大,很多都无法满足工业现场的需求,本文主要研究数字视频图像的获取,以及嵌入式图像处理技术在FPGA芯片上的实现并利用FPGA产生数字视频流控制信号在LCD上还原采集的模拟视频图像,具体阐述了系统硬件平台设计以及软件编写流程．最后对系统主要功能模块仿真．并对系统进行软硬件综合调试。     

A Composite Software Design for the Electronic Switching System

This paper describes a process to achieve modular software for switching systems in a way similar to hardware design manufacturing the components first, then constructing a system using the components needed. To reduce the software maintenance cost in the case of changing switching functions, the following factors were studied: 1) modularity corresponding to divided switching functions; 2) interface standardization among the modules; 3) software structure applicable to different systems. In the trial manufacture for the data switching system, the authors were able to reduce manpower required for designing and debugging, and were able to obtain a structural simplicity and modular portability to other switching systems.     

Broadband networks and services: architecture and control

Broadband networks to support a diverse combination of media and services present two interrelated challenges to the designers: how to devise the proper network architectures to efficiently deliver information, and how to realize the control and software infrastructure for end-to-end support of broadband applications. The new networks and applications that represent the future of interactive digital broadband are not driven by technology alone. We should recognize that the true foundation of the future information networking business involves the uses and benefits that it produces. The applications that are driving the information age are numerous, coming from the areas of entertainment, enterprise systems, telecommunications, education, health, etc. The use of client-server distributed object computing technologies is at the foundation of all the software systems that have been designed and implemented. There are still many Issues to he resolved in the application of this software technology, but it is clear that we must rely on distributed software designs to support the features of interactive broadband services. Concerns over the ability to manage complexity and scalability in these large distributed software systems are a common thread and an indication that the technology still needs to mature     

Analytical modelling and software implementation of synthetic aperture radars

Synthetic aperture radar (SAR) imaging systems are a complement to passive remote sensing. However, the process of image formation is so complex that the final image in the system is formed only after three basic steps: raw data acquisition, forming the signal and the image space. In addition, there are various factors that are involved in the information recorded by SAR within the system and outside the system, such as radar, platform, processing algorithm, imaging region and channel. Each of these factors has been formed by many parameters and this issue adds to the complexity of the behaviour of SAR. Therefore, due to the complexity, providing a model that describes how the SAR imaging system works is highly important. In this paper, the performance of SAR in the image formation section is analytically modelled at first, and then implemented as software. Raw data acquisition is performed in CST software and the signal and image formation are performed in MATLAB software. This implementation provides many abilities, such as better interpretation of SAR images, simulating the effect of the important parameters in SAR images, etc.     

Reliability-estimation and stopping-rules for software testing,based on repeated appearances of bugs

Software-testing (debugging) is one of the most important components in software development. An important question in the debugging process is, when to stop. The choice is usually based on one of two decision criteria: (1) when the reliability has reached a given threshold, and (2) when the gain in reliability cannot justify the testing cost. Various stopping rules and software reliability models are compared by their ability to deal with these two criteria. Two new stopping rules, initiated by theoretical study of the optimal stopping rule based on cost, are more stable than other rules for a large variety of bug structures. The 1-step-ahead stopping rules based on the Musa et. al. basic execution and logarithmic Poisson models, as well as the stopping rule by Dalal and Mallows (1990), work well for software with many relatively small bugs (bugs with very low occurrence rates). The comparison was done by simulation     

Censored software-reliability models

Nonfailure stops of software execution processes can be viewed as a type of censored data. They can occur in a wide range of computing systems (e.g., concurrent computing systems, data sampling systems, transaction processing systems) due to technical or nontechnical reasons. Using existing software reliability models to deal with this type of censored software reliability data, viz, successive inter-stop times, where a stop can be failure or nonfailure stop, means that nonfailure stops are disregarded. This paper develops censored software reliability models, or censored forms of existing software reliability models, to account for nonfailure stops and directly deal with censored data of software reliability. The paper shows how to develop censored forms for the models: Jelinski-Moranda, Schick-Wolverton, Moranda Geometric, and Littlewood-Verrall, and discusses the corresponding validation forms. Censored forms of other software reliability models can be developed in a similar way. Censored software reliability models reduce to noncensored software reliability models if no nonfailure stop occurs