Telecommunication system architectures: Dealing with complexity

The changing environment of telecommunications service operators leads to an increasing customer orientation and an ever increasing complexity. The technical consequence of the increased customer orientation is visible in the higher interest in flexibility engineering. The increasing complexity is becoming the major problem in telecommunication systems of this decade. To deal with this complexity two fundamental capabilities are used: abstraction and structuring. In general, models can be identified on any level of abstraction, e.g. high-level system behaviour models, high-level system architectural models and low-level architectural models. When system complexity increases, more levels of abstraction will be necessary to deal with this complexity. Various methods exist to define models at different levels of abstraction. In this paper three modelling methods are discussed. It is demonstrated that abstraction is used in a similar way in these modelling methods. One particular method for abstraction is the use of the object-oriented paradigm, a powerful approach for modelling as well as for implementation. Additional structuring methods based on considerations with respect to the functionality, however, remain indispensable in order to keep complexity under control. Those methods, stratification and segregation, are specifically relevant in high level architectural models.     

基于Hibernate的轻量级J2EE架构

J2EE是业内一致认为非常优秀的软件架构,并在各种大型应用系统中得到广泛的应用.面向对象的分析方法是大家所熟知的科学的系统分析方法.基于关系型数据库在J2EE架构中使用OOA方法时,我们必须解决对象、关系的映射这一关键性问题.针对对象关系的映射和持久数据的访问,论述了采用Hibernate构建一个功能强大而又简洁、灵活的轻量级J2EE架构的方法.     

面向场景的类型分析

面向对象语言的动态绑定特性，使得它们实现的程序易于演化与维护．但由此而带来的问题是这些程序难以分析与优化。针对现有一些分析方法的精度普遍不够理想的情况．提出一种只对程序的指定场景进行分析的方法。介绍了场景的抽象与场景相关代码的提取，给出了指定场景下类型分析的方法，并以一个实例进行分析，表明丁这种方法可获得更为精确的分析结果，提高类型分析的精度。     

一种基于学分制排课系统的Z规格说明

运用形式化方法建模在软件开发过程中可提高目标系统的正确性和可靠性,在此提出了一种利用Z语言进行语义分析的方法。该方法在序列图Z规范的基础上,用属性集表示对象状态,并将序列图的上下文表示为Z形式约束,通过检查上下文约束与对象状态间的一致性对序列图进行语义分析。在此以一个基于学分制的排课系统为例,使用面向对象的形式规格说明语言Z,描述了一个精确、完整的高校排课系统的形式化数学模型。过程显示,该方法具有精确的描述性和很强的抽象性,能为软件系统的开发和验证提供科学的框架。     

A brief tutorial on the IEEE 1451.1 Standard - Part 13 in a series of tutorials in instrumentation and measurement

The 1451.1 standard addresses the definition of a network capable application processor (NCAP). The NCAP is a piece of hardware and software that acts as a bridge between transducers and the communication network. On the field side, an abstraction layer provides high-level functionality to communicate with transducers. On the network side, an abstraction layer provides high-level functionality to handle network requests. In the middle, the control routine adds intelligence to the NCAP by running algorithms that process the data received by both sides (the field and the network) and decide the next state of the system. The software architecture of the 1451.1 Std. is based on an information model, a data model, and two network communication models.The diversity of fieldbuses and network protocols leads a manufacturer to closed, less-flexible, and generally more-expensive solutions.     

OOP中继承机制剖析

继承是面向对象程序设计方法学中重要的机制。采用继承机制来组织和设计类,可以提高程序的抽象程度,使之更接近与人类的自然思维。研究了继承的特点,通过程序实例,进行对比分析,探讨了C++语言中由继承带来的属性的隐藏和方法的覆盖、遮蔽等重要性质,得出使用继承不仅可以使得大量的代码可以复用,而且可以大大减少代码和数据的冗余度,同时由方法的覆盖可以实现真正意义上的多态,并由此使得程序具有更好的扩展性。     

Incorporating testability considerations in high-level synthesis

In this article we propose two novel methods to improve the testability of the designs produced by high-level synthesis tools. Our first method, loop-breaking algorithm, identifies self-loops in a design generated by a high-level synthesis system and eliminates as many of these loops as possible by altering the register and module bindings. The second method, BINET with test cost, is a binding algorithm that takes the cost of testing into account during the binding phase of the high-level synthesis. The test cost considered in this article is a function of the number of self-loops in the synthesized design. Thus it generates only those solutions that have fewer if any self-loops. Finally we put the two methods together in which we first use BINET with test cost to produce nearly self-loop free designs and we further improve their testability by using the loop-breaking algorithm. We applied these methods to synthesis benchmark circuits and the results of our study, given in this article, show that the designs produced by our method have indeed reduced testability overhead and improved testability.     

基于UML的面向对象的系统建模

UML是一种通用的可视化建模语言，用于对软件进行描述、可视化处理、构造和建立软件系统的文档。它是面向对象分析和设计过程中重要的建模工具。本文以办公自动化系统的建模为实例，介绍了一种基于UML的面向对象的系统建模方法。     

An object-oriented analysis of a BISDN control system with a focus on the UNI protocol object

The control system of a BISDN network will undoubtedly be very complex to design, implement and maintain. Its complexity has led researchers to look for ways of breaking down the problem into smaller and manageable parts. This has motivated the use of an object-oriented approach to analyse and comprehend the BISDN control system. This paper thus presents an object-oriented analysis (OOA) of a BISDN control system. This analysis is based on a method introduced by Coad and Yourdon and comprises five steps. All five steps, namely identifying subjects, identifying objects, identifying structures, defining attributes, and defining operations, will be worked out in detail with an emphasis on the user network interface (UNI) signalling protocol object. Four subjects, nine objects, and three structures are identified in the problem space at hand. This structuring offers a framework to analyse in detail the three aspects, data, structure and dynamic behaviour, of the UNI signalling protocol. A parallel between this approach and the well known approach used by the International Telecommunication Union (ITU) for specifying signalling protocols and contained in Recommendation I.130 is drawn. The Coad and Yourdon OOA approach applied to a BISDN control system can be used for the analysis of different aspects of such systems. This paper focuses on the UNI signalling protocol object which leads to a complete specification. Any protocol resulting from such analysis can be claimed to be object-oriented protocol. This approach offers modularity and thus offers a way of structuring the problem space into identifiable objects and data. Full benefits of object orientation can be gained only in the consistent use of object orientation throughout all steps in the development process. The proposed approach allows one to create libraries of generic procedures which can be reused in specific implementations.     

小型餐饮消费管理系统的研究与设计

基于提高餐饮企业业务效率的目的,采用面向对象的设计方法（OOA）,通过系统结构设计和前端开发,以A-DO．NET技术、C#语言和SQL后台数据库为基础。利用．NET的数据库访问技术ADO.NET技术实现程序与数据库之间的连接、打开和关闭等具体实验,得出了以．NET技术和C／S结构构建的小型餐饮消费管理系统具有运行稳定、成本低、安全可靠的功能。     

Matisse: A System-on-Chip Design Methodology Emphasizing Dynamic Memory Management

MATISSE is a design environment intended for developing systems characterized by a tight interaction between control and data-flow behavior, intensive data storage and transfer, and stringent real-time requirements. Matisse bridges the gap from a system specification, using a concurrent object-oriented language, to an optimized embedded single-chip hardware/software implementation. Matisse supports stepwise exploration and refinement of dynamic memory management, memory architecture exploration, and gradual incorporation of timing constraints before going to traditional tools for hardware synthesis, software compilation, and inter-processor communication synthesis. With this approach, specifications of embedded systems can be written in a high-level programming language using data abstraction. Application of MATISSE on telecom protocol processing systems in the ATM area shows significant improvements in area usage and power consumption.     

Quality engineering tools used to design & optimize a mobile measurement station [Instrumentation Notes]

During the design and construction of a distributed measurement system, design engineers face many basic questions. How does one properly choose a structure and actual solutions for the key elements of the system? Which elements are important? How does one guarantee a suitable level of operating quality and reliability? A broad knowledge base and technical experience are necessary to answer these questions. The consumer's expectations for the product need to be met. The designer's subjectivity should be minimized. In this column, we discuss the use of two tools, the Quality Function Deployment (QFD) method which comes from quality engineering rules and the Analytic Hierarchy Process (AHP) which comes from operations research. Implementing QFD during the design process can focus the attention of the designer on the most important elements of reliability and work quality. The AHP method helps the engineer make complex decisions in designing today's measurement systems that have many extreme optimization problems. Using these methods should decrease the cost of manufacturing and maintenance of measuring systems. We explain these methods and then show how they work in designing a distributed system for a mobile measurement station (MMS).     

Object-oriented analysis of signalling and control in broadband networks

This paper analyses the problem of providing call, connection, channel, and service control in broadband and intelligent networks to support a wide variety of services. A formal methodology called object-oriented analysis (OOA) is used to analyse this problem. Three types of OOA models are constructed: the information model, state models and the object communication model. From these models, a distributed call processing architecture that proposes separate servers for call control, connection control, channel control and service control, is derived. Based on the events used for inter-object communication in the object communication model, service-specific and control-function specific application service elements are defined as client-server based protocols.     

HASoC—Towards a New Method for System-on-a-Chip Development

We present a novel method (HASoC) for developing embedded systems that are targeted at system-on-a-chip implementations. The object-oriented development method is based on the experiences of using our existing MOOSE technique and supports a lifecycle that explicitly separates the behavior of a system from its implementation technology. The design process, whichuses a notation based on extensions to UML-RT, begins with the incremental development and validation of an abstract executable model of a system. Subsequently, this model is partitioned into hardware and software sub-systems to create a committed model, which is mapped onto a system platform that defines the implementation environment. The methodology emphasizes the reuse of pre-existing hardware and software platforms to ease the development process. A partial example application is presented in order to illustrate the main concepts in our methodology.     

加强电机结构认识实习环节,提高电机学教学质量

“电机学”课程的理论抽象，学生必须对电机结构有清晰的了解，才能掌握好理论知识，结构认识实习成为重要的一个教学环节。为解决电机结构认识实习中存在的问题，激发学生实习的兴趣和热情，我们对实习形式和实习手段都进行了较大改进，建立了以现场实习、实验室内的电机拆装、电机结构录像、三维结构模型相结合的实习形式。取得了良好的教学效果。     

Symbolic NFA scheduling of a RISC microprocessor

We describe a set of techniques for representing the high-level behavior of a digital subsystem as a collection of nondeterministic finite automata, NFA. Desired behavioral dynamics such as functional dependencies, sequential timing, and sequencing, and control state are similarly modeled. Using techniques similar to that used in formal model checking, we implicitly explore the possible execution sequences of the system, obeying all imposed constraints. This provides a very general, systematic mechanism for performing high-level synthesis of cyclic, control dominated behaviors, constrained by arbitrary sequential constraints. In this paper, we show that these techniques are scalable to practical problem sizes and complexities by constructing a high-level model of a (MIPS IV) RISC microprocessor and then performing exact scheduling and related design tradeoffs on this model. The model is constructed at the level of register transactions to address the majority of contention and arbitration issues of architectural interest.