Scaling network services using programmable network devices

The NEon system offers an integrated approach to architecting, operating, and managing network services. NEon uses policy rules defining the operation of individual network services and produces a unified set of rules that generic packet-processing engines enforce.     

A programmable network virtual machine

The increasing diversity of resources which is becoming available to users through the introduction of computer networks has opened up new areas of investigation. One of the problems encountered is that of providing uniform and common access procedures where functionally similar facilities exist on different systems. A lack of standardization in this area can inhibit the very benefits derived through the use of networks. Another aspect is the possibility of achieving genuine resource sharing among several different systems in the network. This can lead to the development of virtual systems that embody the most desirable characteristics of the various real component systems.One approach to solving these problems is to create an agent that is able both to automate remote access procedures on the user's behalf, and provide him with the most appropriate network interface. This paper describes the design of a multi-user virtual machine that is able to perform this role. The machine is programmable by a high-level language which has been specially designed to meet the requirements of a network access environment. It is conjectured that the use of a special purpose high-level language is a most flexible and powerful means of generating particular network agents and that this technique permits the automation of a wide variety of network access procedures.     

基于USB的大型建筑分布式数据采集系统

本文阐述了一种基于AT89C5131的分布式的数据采集系统。给出了采集系统的软、硬件的设计思路。系统采用实时的时钟源和多种的数据总线接口,实现了准确的、大覆盖范围的、大存储量的自动数据采集;数据通过USB数据总线接口下载。     

A programmable analog neural network processor

An analog neural network breadboard consisting of 256 neurons and 2048 programmable synaptic weights of 5 bits each is constructed and tested. The heart of the processor is an array of custom-programmable synapse (resistor) chips on a reconfigurable neuron board. The analog bandwidth of the system is 90 kHz. The breadboard is used to demonstrate the application of neural network learning to the problem of real-time adaptive mirror control. The processor control is 21 actuators of an adaptive mirror with a step-response setting time of 5 ms. The demonstration verified that it is possible to modify the control law of the high-speed analog loop using neural network training without stopping the control loop.     

Hardware spiking neural network prototyping and application

EMBRACE has been proposed as a scalable, reconfigurable, mixed signal, embedded hardware Spiking Neural Network (SNN) device. EMBRACE, which is yet to be realised, targets the issues of area, power and scalability through the use of a low area, low power analogue neuron/synapse cell, and a digital packet-based Network on Chip (NoC) communication architecture. The paper describes the implementation and testing of EMBRACE-FPGA, an FPGA-based hardware SNN prototype. The operation of the NoC inter-neuron communication approach and its ability to support large scale, reconfigurable, highly interconnected SNNs is illustrated. The paper describes an integrated training and configuration platform and an on-chip fitness function, which supports GA-based evolution of SNN parameters. The practicalities of using the SNN development platform and SNN configuration toolset are described. The paper considers the impact of latency jitter noise introduced by the NoC router and the EMBRACE-FPGA processor-based neuron/synapse model on SNN accuracy and evolution time. Benchmark SNN applications are described and results demonstrate the evolution of high quality and robust solutions in the presence of noise. The reconfigurable EMBRACE architecture enables future investigation of adaptive hardware applications and self repair in evolvable hardware.     

A programmable text-editing system

A full-screen text-editor is described which has been augmented with a programming facility. The facility consists of an interpreter which inspects a program and generates output to drive the editor. This bridges the gap between text-editing and text-processing and allows the editor to carry out complicated operations. The features of the editor are described briefly, and the programming language employed by the interpreter is presented. Several applications are discussed to show the range and versatility of the system.     

A model-based computer-aided prototyping system

Computer aided prototyping systems which allow application domain experts to compose prototypes using domain specific components, semantics, and primitives can reduce the time and effort needed for prototyping considerably.The notion of domain model is introduced as a vehicle for defining, generating, and categorizing domain specific components. Facilities to compose the components generated from the domain model to implement complex functionality are presented.A rapid prototyping system which provides a domain modeling tool and a visual direct manipulation composition tool is described. The main element of the domain modeling tool is a domain modeling language which provides: (i) a class construct to define object, (ii) rule, trigger, event, and relationship constructs to define interactions among objects, and (iii) process, task, and signal constructs to define the activities in the domain.The composition tool is the extension of a visual tool called IntelligentPad (IP) which supports unified data and control flows through a simple paste and connect metaphor. Domain models are translated to generate components, which are then composed using the extended IP.     

Knowledge-based system for rapid prototyping

In recent years it has been noticed that rapid prototyping produces better software products. Research on combining Artificial Intelligence and software engineering has also been conducted for a number of years. A knowledge-based system for rapid prototyping is presented. In the system, the Frame-and-Rule Oriented Requirements Language and a methodology are developed to provide an integrated means of prototyping throughoyt the software life cycle. The particular application domain to be modelled is represented in terms of objects and activities. FRORL, which uses the concept of frames and production systems, describes the problem domain's objects and activities in a natural way. With the support of a knowledge base, a software prototype can be rapidly developed using FRORL. The system has been implemented using Prolog on a VAX-11/780 computer.     

A multi-material virtual prototyping system

This paper proposes a multi-material virtual prototyping system for digital fabrication of heterogeneous prototypes. It consists mainly of a topological hierarchy-sorting algorithm for processing slice contours, and a virtual simulation system for visualisation and optimisation of multi-material layered manufacturing (MMLM) processes. The topological hierarchy-sorting algorithm processes the hierarchy relationship of complex slice contours. It builds a parent-and-child list that defines the containment relationship of the slice contours, and subsequently arranges the contours in an appropriate sequence, which facilitates toolpath planning for MMLM by avoiding redundant tool movements. The virtual simulation system simulates MMLM processes and provides stereoscopic visualisation of the resulting multi-material prototypes for quality analysis and optimisation of the processes.     

可编程控制器系统可靠性的设计

PLC广泛应用于社会生产各个行业，因此讨论其可靠性以及提出设计方案是非常必要的。文章分析了最为关注也是最为影响PLC可靠性的供电系统设计和接地设计，首先具体提出了供电系统保护措施的四种方法以及一般PLC系统供电电源设计，在I／O模板供电电源设计中则给出了24V直流和220V交流两种I／O模板的供电设计，最后分析了接地设计中应注意的问题并着重分析了接地电阻的选择。     

The principles and prototyping of a knowledge-based diabetes management system

This paper describes the principles and prototyping of a computer-based system being developed to assist in the management of diabetes mellitus. Unlike other approaches based upon mathematical modelling or the use of computer algorithms, this system adopts one derived from artificial intelligence, seeking to incorporate the dynamics of glucose and insulin in a manner which reflects their clinical importance. The resultant logical model (qualitative algebra) defines the relationships between changes in insulin dose and site and time of injection and glycaemic response. In this manner the computer-based system, implemented in Prolog, can be used to provide advice concerning insulin therapy by means of making qualitative predictions of patient outcome of blood glucose profile resulting from alternative insulin regimens.     

A programmable analog VLSI neural network processor forcommunication receivers

An analog VLSI neural network processor was designed and fabricated for communication receiver applications. It does not require prior estimation of the channel characteristics. A powerful channel equalizer was implemented with this processor chip configured as a four-layered perceptron network. The compact synapse cell is realized with an enhanced wide-range Gilbert multiplier circuit. The output neuron consists of a linear current-to-voltage converter and a sigmoid function generator with a controllable voltage gain. Network training is performed by the modified Kalman neuro-filtering algorithm to speed up the convergence process for intersymbol interference and white Gaussian noise communication channels. The learning process is done in the companion DSP board which also keeps the synapse weight for later use of the chip. The VLSI neural network processor chip occupies a silicon area of 4.6 mmx6.8 mm and was fabricated in a 2-mum double-polysilicon CMOS technology. System analysis and experimental results are presented.     

Computer-aided prototyping for a command-and-control system usingCAPS

A case study that shows the feasibility of using computer-aided prototyping to validate a C³I system's requirements is presented, and the enabling technology is described. The C³I prototype developed has characteristics typical of embedded software, including distributed processing, hard real-time constraints, multiple, predefined hardware interfaces, and complex requirements. A color, multiwindow executable Ada prototype that can process tactical data from multiple interfaces in real time was generated. The prototype was used to get feedback about the proposed design's effectiveness, performance, and structure and to evaluate the soundness of the design decisions     

基于可编程逻辑控制器的微波通信系统设计

本文对可编程逻辑控制器(PLC)在微波通信系统中的应用进行了介绍,分析了数字微波通信的原理,并给出了利用PLC实现通信系统的方案设计。同时对该系统的硬件系统进行描述,给出了软件实现方法,并增加了通信校验和看门狗功能保证整个系统的可靠性。     

可编程微波炉控制器的设计

基于可编程逻辑器件EPM240T100C5,使用硬件描述语言VHDL,采用"自顶向下"的设计方法,编写一个微波炉控制器的芯片。介绍了微波炉控制器的设计思路与模块划分,应用Quartus II软件对每个模块和主程序分别进行了调试,并硬件下载到开发板上进行了模拟调试。     

PLC控制系统的编程技术

介绍了可编程序控制器控制系统开发过程中,PLC梯形图编程要注意的问题及相应的编程技术。     

基于构件技术的快速样机原型的软件框架

以自主研发的HLRESP（honeycomb-like rapid embedded system platform）快速样机系统为基础,提出一种基于构件技术地快速样机原型的软件框架。该软件系统以Eclipse开放平台为基础,并采纳了角色的概念,使之能够支持一定程度上的多人协作开发任务。提出了板级IP（BLIP）的概念,使其在软件系统中的管理方式与FPGA内的IP管理方式一致,简化了软件设计工作。对于IP库的管理,使用了XML（extensible markup language）表示IP（intellectual property）,结合CVS版本控制系统,使得用户能够方便地从IP构件库中获得、配置并集成IP。     

Hybrid rapid prototyping system using machining and deposition

Many rapid prototyping (RP) systems are commercially available, and others are introduced daily. RP has proven to be an effective tool for dramatically reducing the time and expense involved in the realization of a new products and for overcoming the bottlenecks of existing manufacturing processes. However, its fields of application are currently saturated, and the emphasis has moved towards using RP for short-run manufacture. The current need is for a technique that will produce finished parts of the required quality in the shortest possible time, and which meet this need, the focus now falls on improvements in production speed, accuracy, variety of materials, and cost. For these practical reasons, we concentrated on a new form of hybrid-RP system, which performs both deposition and machining in a single station. Our proposed system meets the requirements of material deposition (RP) and material removal (CNC) at the process planning and manufacturing level. We believe that this new production system, which incorporates a combined RP concept, offers an optimum manufacturing solution by adopting the advantages of the RP and CNC systems. In this paper, we describe the system architecture and the fabrication process in detail and present the framework of the process planning system and the concepts of the geometric algorithms involved in developing such an environment.