The Florida Digital Archive and DAITSS: a working preservation repository based on format migration

The Florida Digital Archive is a long-term digital preservation repository for the use of the libraries of the public universities of Florida. It is managed by the Florida Center for Library Automation (FCLA) and based on Dark Archive in the Sunshine State (DAITSS), repository software developed by FCLA with the aid of grant funding from the Institute of Museum and Library Services (IMLS). DAITSS is designed to implement active preservation strategies based on format transformations including forward migration, normalization, and localization. As a case study, the Florida Digital Archive and DAITSS show that active preservation strategies can be incorporated into repository applications from the start, and that doing so affects all aspects of application design. The Florida Digital Archive has been in production since November 2005. The DAITSS application is nearing completion and will be released as open source software in 2006.     

Digital fuzzy logic controller: design and implementation

In this paper, various aspects of digital fuzzy logic controller (FLC) design and implementation are discussed, Classic and improved models of the single-input single-output (SISO), multiple-input single-output (MISC), and multiple-input multiple-output (MIMO) FLCs are analyzed in terms of hardware cost and performance. A set of universal parameters to characterize any hardware realization of digital FLCs is defined. The comparative study of classic and alternative MIMO FLCs is presented as a generalization of other controller configurations. A processing element for the parallel FLC architecture realizing improved inferencing of MIMO system is designed, characterized, and tested. Finally, as a case feasibility study, a direct data stream architecture for complete digital fuzzy controller is shown as an improved solution for high-speed, cost-effective, real-time control applications     

LANSF: A protocol modelling environment and its implementation

LANSF is a software package that was originally designed as a tool to investigate the behaviour of medium access control (MAC) level protocols. These protocols form an interesting class of distributed computations: timing of events is the key factor in them. The protocol definition language of LANSF is based on C, and protocols are specified (programmed) as collections of communicating, interrupt-driven processes. These specifications are executable: an event-driven emulator of MAC-level communication phenomena forms the foundation of the implementation. Some tools for debugging, testing, and validation of protocol specifications are provided. We present key features of LANSF at the syntactic level, comment informally on the semantics of these features, and highlight some implementation issues. A complete example of a LANSF application is discussed in the Appendix.     

Digital filters for clustered-OFDM-based PLC systems: Design and implementation

This work aims to investigate the design and implementation of digital filters for separating clusters in a clustered-orthogonal frequency-division multiplexing scheme for power line communication systems. In this regard, we formulate the mathematical problem and present a criterion which is capable of searching for digital filters that maximizes data rate. In the following, several finite impulse response and infinite impulse response digital filters are analyzed in order to validate the proposed criterion and to verify the best one which fulfills the given constraints. Furthermore, regarding only the best digital filters obtained, a finite precision and complexity analyses are carried out by using a field-programmable gate array device. Based on numerical results, we show that finite impulse response equiripple minimum phase and infinite impulse response Chebyshev type II digital filters yield the best data rates among the chosen digital filters. Moreover, we point out that equiripple minimum phase digital filters consume more hardware resources than Chebyshev type II digital filters, although the first one deal better with the field-programmable gate array constraints when more bits are used to implement the digital filter. Due to that, finite impulse response digital filters are more indicated to be implemented in a field-programmable gate array device.     

组播树维护策略的研究和实现

在IP组播模型、Overlay Network和Peer-to-Peer等技术的基础上发展而来的应用层组播技术正逐步成为一个流媒体直播的有效解决方案。树形组播方案构造简单,维护开销较小,可扩展性较好,比较适合于大规模的组播应用,但是其可靠性较差。通过比较研究其他P2P算法对节点稳定性和节点距离的衡量策略,对树形拓扑维护策略PeerCast进行改进,设计并实现了一个基于该改进算法的流媒体直播系统。应用表明,该算法能动态适应节点数达数百,节点生存周期较短的组播应用,较大程度上减小节点加入退出对QoS的影响。     

Design,implementation, and performance analysis of PKI certificate repository using LDAP Component Matching

The X.509 certificate stored in a Lightweight Directory Access Protocol (LDAP) certificate repository requires secure and flexible means to make assertions against its component values such as the identity of its owner, issuer, and the intended usage of the public key contained therein. LDAP has traditionally lacked this ability because its string‐based encodings do not have a standardized way of carrying structural information of complex syntaxes as in X.500. The traditional remedies to this limitation are (1) to provide certificate‐specific matching for a limited set of components and their combinations and (2) to extract and store the certificate components in separate searchable attributes. Neither of these remedies is considered complete, because the former lacks flexibility while the latter heightens complexity in managing the integrity of the certificate repository and doubles storage requirements. Owing to the significant downside of these remedies, we investigate the possibility of an Abstract Syntax Notation One‐based Component Matching alternative. In this paper, we present (1) the design and implementation of the LDAP Component Matching for an OpenLDAP directory server to facilitate its use as the certificate repository in Public Key Infrastructure (PKI), (2) various optimization mechanisms to increase the performance of the Component Matching and their implementation in OpenLDAP, and (3) the detailed performance analysis of the LDAP directory server as a certificate repository in comparison with the traditional certificate‐specific matching and the attribute extraction approaches. We show that Component Matching, if equipped with the optimization techniques proposed in this paper, outperforms the traditional approaches. Copyright © 2007 John Wiley & Sons, Ltd.     

基于工作组的IPsec安全策略系统研究与实现

参考了IETF工作组提出的安全策略系统标准框架,提出了基于工作组的安全策略系统的思想。结合一个端到端安全通信原型系统,设计了基于工作组的安全策略系统的总体框架,讨论了该安全策略系统的功能模块及采用的关键技术。     

农田环境监测系统设计与实现

针对农业生产的自动化管理需求,介绍了ARM与Zig Bee技术相结合设计农田环境监测系统的方法。硬件部分采用Zig Bee外接传感器设计环境数据采集节点,采用S3C2440处理器和CC2530设计协调器网关,其中CC2530与ARM之间采用SPI口进行数据通信。软件部分基于IAR平台结合Z-Stack协议栈构建Zig Bee无线监测网络,用于采集并传输影响农作物生长的现场环境信息,数据在基于ARM与Zig Bee技术相结合而开发的网关节点处实现汇聚,最终通过串口发送到基于VC++6.0与数据库技术开发的上位机监测系统。经测试,网关节点能实时接收传感器节点的数据,并通过串口成功上传到上位机监测系统,实现实时数据监测、动态分析、历史查询和异常报警功能,系统具有较好的稳定性和实用性。     

Design and implementation of an adaptable software environment

In any major software project, a large volume of project-related information must be maintained and manipulated throughout the software life-cycle. Often this information is scattered, in different media ranging from scraps of papers to program listings, poorly cross-referenced, and inaccessible. TRIAD, an adaptable, integrated software development environment, has been designed to integrate and manage all this information in an organized and structured manner.

The TRIAD tool-box environment supports different methodologies to guide the users during development and maintenance of project related information. The environment can be customized by selecting a set of forms which enforce a particular methodology. These forms help develop, integrate, and maintain project information. Forms for a methodology can be tuned to reflect a project-team's experience. When customized by the tuned methodology, TRIAD can provide better project oriented support.

TRIAD uses grammar forms as its organizational model. This paper will discuss the advantages of using grammar forms in the modeling and implementation of an adaptable software information editor, within the TRIAD tool-box environment.     

嵌入式板级支持环境设计与实现

简要说明板级支持环境(board support environment,BSE)的功能及其在嵌入式系统研发中的重要性;设计一个功能完善的板级支持环境系统;该系统具备自引导功能,并可根据用户的命令执行相应的操作;使用这一系统可使嵌入式系统研发脱离对调试器或仿真器的依赖;以MIPS体系结构为例,就实现这一系统的若干关键问题给出解决方案.     

带有约束的"长城"安全策略模型及其实现

"长城"安全策略模型是商业信息领域中重要的安全策略模型之一,它能够巧妙地将自由选择与强制访问控制结合在一起,既具有自主控制的灵活性,又能对存取操作加以限制.但是"长城"安全策略模型仍不能很好地满足实际的需要,存在着一定的缺陷,因此增加时间约束,职责分离约束和基数约束,对"长城"安策略模型进行扩展,提出一种带有约束的"长城"安全策略模型.     

TinyOS集成开发环境的设计与实现

TinyOS是针对资源非常有限的无线传感器网络节点而设计的构件化操作系统,采用构件化描述语言nesC进行开发。由于采用基于构件的软件工程（CBSE）技术,TinyOS可以看成是一个构件库,简化了无线传感器节点上的应用程序设计,但目前缺乏系统配套的构件管理工具和高效集成开发环境(IDE)。分析了构件化描述语言nesC和TinyOS的开发过程,设计并实现了一种构件化集成开发环境及其构件管理器。根据分析和实际使用,该开发环境能有效地简化开发流程并提高开发效率。     

事件关联策略的实现及其应用研究

事件关联是重要的故障定位策略，已成为网络故障管理的研究热点。全面阐述实现事件关联策略的几种技术及其应用，指出它们共同存在的问题。     

Digital implementation of time-optimal attitude control

An experimental single-axis, time-optimal attitude control computer was designed and built using digital differential analyzer (DDA) techniques. A relatively simple digital implementation of the control functions was obtained while holding the computational errors within predetermined limits. To evaluate the capabilities, limitations and accuracy attainable in digital implementarion of such a system, tests were conducted in which an analog computer was used to simulate the dynamics of the controlled vehicle. It was shown that the digital control system performed its function properly, providing a true time-optimal control, and that the computation errors were kept below the design limit. The primary concern of this paper is to show how basic DDA techniques can be used to implement the control functions required in attitude control of a space vehicle and to present the system characteristics resulting from such a design approach. Techniques used for reducing DDA computational errors are also given consideration. It will be seen that the truncation errors can be minimized and limited to a zero-averaged error to prevent hysteresis or drift effects. Unlike truncation errors, round-off errors cannot be completely eliminated and can cause localized irreversibility of computations (hysteresis effects). In spite of this, harmful drifts or accumulated errors are not produced because of the closed-cycle nature of the control problem as viewed in the error phase plane.     

Digital twin-based industrial cloud robotics: Framework,control approach and implementation

Industrial cloud robotics (ICR) integrates cloud computing with industrial robots (IRs). The capabilities of industrial robots can be encapsulated as cloud services and used for ubiquitous manufacturing. Currently, the digital models for process simulation, path simulation, etc. are encapsulated as cloud services. The digital models in the cloud may not reflect the real state of the physical robotic manufacturing systems due to inaccurate or delayed condition update and therefore result in inaccurate simulation and robotic control. Digital twin can be used to realize fine sensing control of the physical manufacturing systems by a combination of high-fidelity digital model and sensory data. In this paper, we propose a framework of digital twin-based industrial cloud robotics (DTICR) for industrial robotic control and its key methodologies. The DTICR is divided into physical IR, digital IR, robotic control services, and digital twin data. First, the robotic control capabilities are encapsulated as Robot Control as-a-Service (RCaaS) based on manufacturing features and feature-level robotic capability model. Then the available RCaaSs are ranked and parsed. After manufacturing process simulation with digital IR models, RCaaSs are mapped to physical robots for robotic control. The digital IR models are connected to the physical robots and updated by sensory data. A case is implemented to demonstrate the workflow of DTICR. The results show that DTICR is capable to synchronize and merge digital IRs and physical IRs effectively. The bidirectional interaction between digital IRs and physical IRs enables fine sensing control of IRs. The proposed DTICR is also flexible and extensible by using ontology models.     

Information architecture: the repository alternative

The skillful design of an information architecture that suits a healthcare organization is a top priority for information managers. But they have been hampered both in their conceptual approach to managing information flow and their technological capabilities for designing that flow. Information--both clinical and administrative--must be fluid and accessible. These key success factors lie in the increasingly prevalent database repository approach. And the technology is here to make it happen.     

面向软件开发信息库的数据挖掘综述

总结了近年来挖掘软件开发信息库的研究工作,主要包括研究内容和采用的数据挖掘方法,最后讨论了软件开发信息库研究的未来发展前景.     

基于中间盒的SDN信息服务中心策略实施架构

中间盒是一种网络管理员手动设置行为策略的设备;软件定义网络（software-defined network,SDN）的出现使得中间盒实施策略的可能性变得多样化。为改善信息服务中心的安全防护,提出一种无须管理员参与即可响应网络事件的基于SDN的动态中间策略实施架构,提出可以满足控制器与中间盒之间通信的接口。在虚拟机中实施了具有防火墙和入侵防御系统（intrusion prevention system,IPS）的中间盒原型来评估策略执行体系,验证原型获得的实验效果。结果表明,该体系结构能够在不影响网络性能的前提下动态执行中间盒策略,使网络应用程序能够正常运行。