基于CAD技术的数字逻辑系统

数字逻辑系统的设计离不开计算机辅助设计CAD工具的帮助，尤其是VHDL硬件描述语言。该语言采用模块化的设计方法，自顶向下完成全部设计和综合过程，最终生成印刷电路板或专用集成电路，论述了高级语言VHDL的行为模块描述和结构模式描述，介绍了数字逻辑系统的设计方法和步骤，继而通过一个简单设计实例讨论了VHDL语言模块化的综合描述过程。     

基于VHDL的FIR低通数字滤波器设计与仿真

以FIR数字滤波器的设计为例,介绍了使用VHDL硬件描述语言进行数字逻辑设计的过程和方法,给出了在Quartus Ⅱ的集成开发环境下的相应VHDL代码,并且利用Quartus Ⅱ内部的仿真器对设计进行了脉冲响应仿真和验证。     

基于XYZ/ADL的网络中心化仿真运行支撑平台体系结构形式化描述

网络中心化仿真运行支撑平台体系结构是为了满足动态构建仿真任务共同体而提出的相应支撑环境。采用基于XYZ/ADL的双重软件体系结构描述框架,分别从图形语言和形式语言对仿真运行支撑平台体系结构进行了描述并对仿真任务共同体构建中仿真核心服务层实施了分解与逐步求精。该体系结构描述方法不但从可视化角度表示了仿真运行支撑平台体系结构框图及行为抽象,还从形式化角度验证了体系结构设计的正确性和完整性。该研究是形式化描述方法在军事领域的全新尝试,为仿真运行支撑平台服务的合成与重用机制提供了形式化的理论指导。     

Analyzing partially-implemented real-time systems

Most analysis methods for real-time systems assume that all the components of the system are at roughly the same stage of development and can be expressed in a single notation, such as a specification or programming language. There are, however, many situations in which developers would benefit from tools that could analyze partially-implemented systems: those for which some components are given only as high-level specifications while others are fully implemented in a programming language. In this paper, we propose a method for analyzing such partially-implemented real-time systems. We consider real-time concurrent systems for which some components are implemented in Ada and some are partially specified using regular expressions and graphical interval logic (GIL), a real-time temporal logic. We show how to construct models of the partially-implemented systems that account for such properties as run-time overhead and scheduling of processes, yet support tractable analysis of nontrivial programs. The approach can be fully automated, and we illustrate it by analyzing a small example     

Behavioral profiles—a way to model and validate program behavior

Software architecture contains, in addition to its structural part, interaction patterns that can be regarded as part of the architectural solution of the system. The interaction patterns define architecturally significant behavior of the software system. In this paper we propose a visual modeling language, behavioral profiles, for specifying architecturally significant behavioral rules for an application. The language is built on the Unified Modeling Language (UML), which is a visual language widely used in software development. We show how behavioral profiles can be used to support software designers in creating behavioral models that conform to some predefined rules and for ensuring that an application behaves correctly with respect to the rules given in the profiles. A tool called Bebop was built to support software engineers in behavioral profile‐based design and analysis of program behavior. To evaluate the approach and the tools in different application domains, they are utilized in three cases. The size of the applications used in the cases varies from small to quite large software systems, and from academic to industrial ones. The examples demonstrate how the approach presented can be used in practice for different steps in a software engineering process. The examples cover specializing an application framework and monitoring the program execution in run‐time. In addition, they show how behavioral profiles can be used to support guided program comprehension and to validate program execution by analyzing execution traces. Copyright © 2010 John Wiley & Sons, Ltd.     

Studies in artificial aphasia: experiments in processing change

Computational neurolinguistics, an integrated approach to cognitive modelling of neural processes which may subserve natural language performance, attempts to build computational models that model behavior on two levels: at the neural process level and at the human performance level in its normal state and under pathological conditions. HOPE is one example of such a model. It demonstrates how the design and implementation of such models can provide insights into how a brain-like architecture can produce a behavior as complex as natural language. This paper will briefly describe the neurally motivated or 'natural computation' processes which produce the model's observable and verifiable behavioral results. Experiments with artificially induced aphasia on HOPE will then be described, showing that the results of simulation produce hypothesized patient profiles that are unique. These profiles illustrate the suggested contribution of the computational neurolinguistics research approach as a tool for investigating the breakdown of language performance and its potential contribution to understanding brain function.     

Agent-based framework for integrated facility engineering

An agent-based framework for the development of integrated facility engineering environments in support of collaborative design is introduced. This framework aims at integrating design software by allowing better software interoperability. Within their framework, design agents represent various existing design and planning systems that communicate their design information and knowledge partially and incrementally using the Agent Communication Language (ACL). ACL is a formal language proposed as a communication standard for disparate software. It is based on a logic-based language called Knowledge Interchange Format (KIF) and a message protocol called Knowledge Query Manipulation Language (KQML). Design agents are linked and their communication of design information is coordinated via system programs called facilitators in a federation architecture. The federation architecture specifies the way design agents and facilitators communicate in an integrated software environment. In concert with pursuing fundamental research concepts, we have been developing an integrated design software environment that spans different phases of the facility life cycle. This environment serves to demonstrate the primary aspects of this research methodology. In this paper, we first discuss the integration problem and review related research projects. We then present the major aspects of agent-based software engineering methodology and its application to integrated facility engineering. A highlight of the current integrated design environment development is given to illustrate the advantages of this approach. Finally, we summarize and discuss some of the important research issues in light of previous research.