On constructing communication protocols from component-based service specifications

Constructing communication protocols from component service specifications, each of which specifies a subfunction of the target protocol, enables efficient development of a large and complex communication protocol. Concerning this construction, related techniques have been already proposed: integration of component protocol specifications into a single protocol specification and transformation of service specifications to protocol specifications. However, the integration needs special knowledge of communication protocols, and the transformation requires that a large and complex service specification should be developed as input to produce the target protocol. In order to cope with these problems, this paper proposes a new method which at first integrates component service specifications into a single service specification, and then transforms the service specification into the target protocol by a protocol synthesis technique. The most important point of view is that component integration is performed at the service specification level rather than the protocol specification level. Additionally, we define a class of ‘well-formed’ service specification which ensures correctness of the target protocol. As a result, the integration and transformation can be efficiently executed in small state space without special knowledge of communication protocols. Finally, we have shown the effectiveness of the proposed method by constructing a part of the real-life OSI protocol FTAM.     

大规模BurstMode异步控制电路分解与综合

对于现有的Burst Mode异步控制电路综合方法而言,由于在状态归约与赋值阶段需要进行完备的状态空间搜索,面临状态空间爆炸问题,因此仅仅适用于中小规模控制电路.为了提高电路的综合规模,使得Burst Mode异步控制电路走向实用化,提出了一种新的大规模Burst Mode异步控制电路的综合方法:利用Burst Mode状态机所对应有向图的有向回路集合对状态机进行分解,得到相互独立的子状态机;对各子状态机进行调整,采用请求/应答信号实现相应子状态机之间的四段握手通信;设计接口状态机解决相应子状态机之间的仲裁问题.通过实例比较可知,该方法可以大幅度地提高综合规模,降低综合复杂度,减少综合时间.     

基于软件定义的多协议控制器架构设计

为了满足高性能计算平台对软件定义互联的通信需求,设计了一种支持多种通信协议规范,且支持异构协议互联的软件定义多协议控制器架构。通过嵌入可编程硬件电路实现Fiber Channel、Ethernet以及SRIO 这 3 种协议控制器电路公共算粒和私有算粒的互联。多协议控制器可以通过软件定义切换为不同协议,从而满足系统应用中的异构需求。所设计的软件定义多协议控制器基于40 nm工艺实现测试样片流片,经测试,满足3种协议的性能与功能指标要求。     

AMBA片内总线结构的设计

对AMBA片内总线通讯协议进行简要介绍之后，采用Top-Down设计方法完成了AMBA片内总线结构所有控制部件的RTL级硬件建模，并通过逻辑综合、优化得到了门级电路网表。经验证，符合AMBA规范，频率达100MHz。     

通信协议转换在嵌入式控制器上的实现

针对机场航站楼监控系统上位机PLC与现场设备的通信协议不一致,以MOXA公司的UC-7408嵌入式控制器来实现PLC和串口设备的两种通信协议转换为例,阐明如何用嵌入式控制器实现通信协议转换,并提出了一种用C语言编写协议转换程序来实现下位机与上位机监控系统通信的方法,详细介绍了协议转换原理、通信系统的硬件构成以及软件实现方法。该方法已通过测试,具有通信可靠、效率高和实时性强等优点。     

分布式控制系统中PC机与多个智能控制器数据通信的实现

阐述了DB1000智能控制器的通信协议以及主从式通信的原理,采用Pcomm串行通信开发工具实现了分布式控制系统中单台PC机对多台智能控制器的串行通信控制。     

Quadratic stabilization of linear networked control systems via simultaneous protocol and controller design

We derive conditions for quadratic stabilizability of linear networked control systems by dynamic output feedback and communication protocols. These conditions are used to develop a simultaneous design of controllers and protocols in terms of matrix inequalities. The obtained protocols do not require knowledge of controller and plant states but only of the discrepancies between current and the most recently transmitted values of nodes’ signals, and are implementable on controller area networks. We demonstrate on a batch reactor example that our design guarantees quadratic stability with a significantly smaller network throughput than previously available designs.     

Error detection and correction in switched linear controllers via periodic and non-concurrent checks

Control systems that utilize switched linear controllers have proven to be useful (and, in some cases, essential) for accomplishing certain control objectives in particular classes of plants. These controllers are often digital in nature and, as such, are subject to internal hardware malfunctions (faults). In this paper, we present a systematic methodology for constructing embeddings to protect switched linear controllers against hardware faults that corrupt their internal state. Our methodology is based on replacing the original controller with a redundant (higher dimensional) controller that preserves the functionality of the original controller while enabling error detection and correction. More importantly, this methodology allows an external mechanism to detect and identify transient state-transition faults through non-concurrent (e.g. periodic) parity checks. The resulting error detection and correction procedures can then be performed periodically, thereby relaxing the reliability requirements and overhead associated with the checking mechanism.     

基于DeviceNet协议的新型低压断路器智能控制器的设计

针对现有低压断路器控制器与控制网络通信因采用自定义协议而存在通信可靠性低和互换性差的缺点,介绍了一种基于DeviceNet协议的新型低压断路器智能控制器的设计方案,详细介绍了控制器软、硬件设计。该控制器不仅能实现一般控制器的功能,还具有DeviceNet总线接口,可以很方便地与监控中心计算机通信。实验运行结果表明,该智能控制器运行可靠、操作方便。     

Specifying and verifying a broadcast and a multicast snooping cachecoherence protocol

We develop a specification methodology that documents and specifies a cache coherence protocol in eight tables: the states, events, actions, and transitions of the cache and memory controllers. We then use this methodology to specify a detailed, modern three-state broadcast snooping protocol with an unordered data network and an ordered address network that allows arbitrary skew. We also present a detailed specification of a new protocol called multicast snooping (Bilir et al., 1999) and, in doing so, we better illustrate the utility of the table-based specification methodology. Finally, we demonstrate a technique for verification of the multicast snooping protocol, through the sketch of a manual proof that the specification satisfies a sequentially consistent memory model     

协议形式化开发环境的规范语言

LOTOS（languageoftemporalorderingspecification）是一种基于进程代数CCS的协议规范语言，面向协议验证，但它不能描述协议的某些性质．本文提出了一种LOTOS的扩充语言ELOTOS（extendedLOTOS），它在LOTOS的基础上引入了异步通讯机制、时间描述、事件发生的随机性描述．     

A methodology for constructing communication protocols with multiple concurrent functions

A methodology is presented for the construction of communication protocols which perform several distinct functions simultaneously. The construction of such a multi-function protocol consists of three steps: (1) the development of component protocols for the different functions, (2) the integration of component protocols into a merged protocol, and (3) the specification of operational relationship among the component protocols. The conditions required for the resulting merged protocol to retain the safety properties, such as freedom from unspecified receptions, freedom from deadlocks, and boundedness, of the component protocols are discussed. The methodology is simple and facilitates the reuse of existing protocols. Two examples are given to illustrate its usage: a full-duplex data transfer protocol and another data transfer protocol with pipelining and flow control. Huai-An Lin received the B.S.E.E. degree from National Taiwan University, Taiwan, in 1977, and the M.S. and Ph.D. degrees in computer and information science from the Ohio State University, Columbus, Ohio, in 1981 and 1983, respectively. From 1983 to 1985, he was with the Gould Research Center at Rolling Meadows, Illinois. Since 1985, he has been an Assistant Professor of Electrical Engineering at University of Washington, Seattle, Washington. His research interests include computer communication networks, distributed systems, and software engineering. Dr. Lin is a member of the Institute of Electrical and Electronics Engineers and the Association for Computing Machinery.This research was partially supported by the Graduate School Research Fund of University of Washington     

Specification and Verification of Communication Protocols in AFFIRM Using State Transition Models

It is becoming increasingly important that communication protocols be formally specified and verified. This paper describes a particular approach–the state transition model–using a collection of mechanically supported specification and verification tools incorporated in a running system called AFFIRM. Although developed for the specification of abstract data types and the verification of their properties, the formalism embodied in AFFIRM can also express the concepts underlying state transition machines. Such models easily express most of the events occurring in protocol systems, including those of the users, their agent processes, and the communication channels. The paper reviews the basic concepts of state transition models and the AFFIRM formalism and methodology and describes their union. A detailed example, the alternating bit protocol, illustrates varous properties of interest for specification and verification. Other examples explored using this formalism are briefly described and the accumulated experience is discussed.     

分布式智能火灾报警系统综合设计

分布式智能火灾报警系统以AT89C51单片机为核心,利用智能温度传感器,并配以相关外围接口电路。采用RS485通信协议实现与上位机的数据通信。组成集中和区域为一体的多区域多监测点的火灾报警系统。文中给出了火灾报警系统的硬件构成图,对区域报警控制器和集中报警控制器的功能进行了说明,画出了系统软件程序流程图,阐述了实时时钟电路和看门狗电路的硬件设计,并对实时时钟电路的写入与读出程序进行了编程设计。文中的研究具有实际和重要的意义。     

CRDT协议的TLA+描述与验证

无冲突复制数据类型（conflict-free replicated data types，简称CRDT）是一种封装了冲突消解策略的分布式复制数据类型，它能保证分布式系统中副本节点间的强最终一致性，即执行了相同更新操作的副本节点具有相同的状态.CRDT协议设计精巧，不易保证其正确性.旨在采用模型检验技术验证一系列CRDT协议的正确性.具体而言，构建了一个可复用的CRDT协议描述与验证框架，包括网络通信层、协议接口层、具体协议层与规约层.网络通信层描述副本节点之间的通信模型，实现了多种类型的通信网络.协议接口层为已知的CRDT协议（分为基于操作的协议与基于状态的协议）提供了统一的接口.在具体协议层，用户可以根据协议的需求选用合适的底层通信网络.规约层则描述了所有CRDT协议都需要满足的强最终一致性与最终可见性（所有的更新操作最终都会被所有的副本节点接收并处理）.使用TLA+形式化规约语言实现了该框架，然后以Add-Wins Set复制数据类型为例，展示了如何使用框架描述具体协议，并使用TLC模型检验工具验证协议的正确性.     

CAN总线接口电路设计

本文介绍了CAN总线的主要性能及特点,CAN总线在实际工业应用中的总体结构,同时给出了CAN总线协议转换器的硬件设计方法和通信协议。主要研究了CAN总线接口电路设计,把所设计的总线接口电路由微处理器、CAN控制器、CAN总线收发器组成,并且详细介绍了CAN控制器、CAN收发器的功能以及CAN总线接口的硬件电路和硬件条件下的软件设计,主要为后续CAN总线接口电路的应用打下了基础。     

基于Pcomm的PC机与单片机串行通信的实现

讨论了用Pcomm软件包实现PC机与PIC系列单片机串行通信的方法，从硬件设计，PIC单片机通信程序设计，C＋＋环境下使用PcommLibrary软件包的有关函数编制PC机的通信程序等方面进行论述，并简单介绍了PIC单片机串行通信的基本原理，给出了具体的通信程序。     

Implementation of real-time distributed control for discrete event robotic systems using Petri nets

This article presents a systematic method of modeling and implementing real-time control for discrete-event robotic systems using Petri nets. Because, in complex robotic systems such as flexible manufacturing systems, the controllers are distributed according to their physical structure, it is desirable to realize real-time distributed control. In this article, the task specification of robotic processes is represented as a system control-level net. Then, based on the hierarchical approach, it is transformed into detailed subnets, which are decomposed and distributed into the local machine controllers. The implementation of real-time distributed control through communication between the system controller and the machine controllers on a microcomputer network is described for a sample robotic system. The proposed implementation method is sufficiently general, and can be used as an effective prototyping tool for consistent modeling, simulation, and real-time control of large and complex robotic systems.     

The synthesis of communication protocols

We define a notation (specification language) for describing desired patterns of communication among components of a distributed system through multiport, unreliable channels. Our language specifies the network topology, and the kinds of information transmission desired. We give a polynomial-time algorithm for determining whether a specification is satisfiable; our algorithm can actually construct a protocol that achieves the specified exchange of information, optimized with respect to two possible criteria. Examples suggest that our method can automatically synthesize reasonably complex protocols.