基于嵌入式Web的远程可控电源插座设计

为了实现对电器的远程控制,运用嵌入式Web技术,设计了一个可通过互联网进行远程访问和控制的电源插座系统。该系统采用开源Boa作为嵌入式Web服务器,选用光电耦合器与可控硅设计控制模块电路。用户通过网页浏览器访问该系统,可对各插座开关进行打开或关闭的操作,进而远程控制与其相连接的电器。测试表明,该系统设计合理,功能实用,操作简便,易于扩展,可广泛用于对家用电器或工业电器的远程控制。     

基于FPGA的远程信息家电监控系统

为了适应家电系统的要求和针对现有的MCU、ARM监控系统设计的不利扩展性和设计的复杂性,提出了基于GPRS、Internet和SOPC家电远程监控系统的方案。采用FPGA设计了基于NiOSⅡ软核处理器和IP组件的家庭网关硬件系统;并在NiosⅡ处理器上移植uClinux操作系统、采用嵌入式C语言编写了CGI程序实现动态Web服务器交互式访问。系统实现了GPRS无线接入和Internet有线接入访问Web服务器,系统真正意义实现了SOPC。     

一个嵌入式实时Java OS的设计及实现

针对嵌入式Inernet环境的特定要求，提出了一个嵌入式的实时Java OS—WebitJOS。WebitJOS在资源受限的嵌入式Internet环境下自身提供了对实时线程的调度、同步和异步处理的内部实现，消除了Garbage collection内存管理不确定性所产生的实时程序设计的障碍，并且提供了，从Java代码直接访问物理内存、寄存器及内存映射I／O的能力。根据嵌入式Internet系统对实时性、确定性的要求，用形式化语言描述了WebitJOS中实时线程及相关内存区的状态转换关系，并结合实例对WebitJOS相关的实时性能进行了测量和评价.     

A protocol for wide area secure networked appliance communication

This article describes problems associated with remotely accessing networked appliances (e.g., from the Internet). Networked appliances are widely viewed as the “next wave” of devices on the Internet. We discuss some possible uses for networked appliances and the requirements for communicating with them. We present details of a solution to meet these communication requirements based on the IETF Session Initiation Protocol. In addition, we discuss the rationale for our approach and reasons other approaches were not adopted. An example of the use of the SIP in this domain is presented to illustrate how the solution can be used. We conclude with outstanding challenges and reiterate advantages of this approach     

An overview of web caching replacement algorithms

The increasing demand for World Wide Web (WWW) services has made document caching a necessity to decrease download times and reduce Internet traffic. To make effective use of caching, an informative decision has to be made as to which documents are to be evicted from the cache in case of cache saturation. This is particularly important in a wireless network, where the size of the client cache at the mobile terminal (MT) is small. Several types of caching are used over the Internet, including client caching, server caching, and more recently, proxy caching. In this article we review some of the well known proxy-caching policies for the Web. We describe these policies, show how they operate, and discuss the main traffic properties they incorporate in their design. We argue that a good caching policy adapts itself to changes in Web workload characteristics. We make a qualitative comparison between these policies after classifying them according to the traffic properties they consider in their designs. Furthermore, we compare a selected subset of these policies using trace-driven simulations.     

基于蓝牙技术的嵌入式信息家电网络系统设计

随着信息家电的发展以及人们对Internet依赖性的增强,家庭网络代表一种新理念正被越来越多的人所关注。利用蓝牙技术可以将微机与各种智能家电设备连接成一个方便实用的嵌入式无线家庭网关。在研究该家庭网关应完成功能的基础之上,提出以S3C2410为核心的家庭控制子网的实现方案。该家庭网关对外与Internet相连,对内采用蓝牙BlueCore2 External模块和家电通信,从而实现通过Internet上的计算机对家庭内部设备的远程监控。     

一种基于8位MCU的嵌入式Internet应用方案

研究一种基于8位MCU的嵌入式Intemet应用方案,解决一类数据通信量不大、实时性要求不高的信息家电接入Intemet的问题。采用AT89C55作为信息家电接入Intemet的MCU,RTLS019AS控制以太网帧的收送,A／D和电平转换芯片实现数据的采集和电平转换,实现远程PC对信息家电的监测和控制。介绍了基于8位MCU的嵌入式Intemet应用方案的系统结构、嵌入式TCP／IP协议栈、系统硬件和软件设计。对基于该方毒实现的一个嵌入式Intemet应用进行了测试。     

Architecture d’un réseau actif à base de services Web

This paper presents a novel active architecture for building and deploying network services:aswa, Web Services based Active network Architecture. At the architectural level,aswa defines an active node whose functionalities are divided into the Node Operating System, the Execution Environment, and the Active Applications. At the implementation level,aswa is a Web Services based platform where new components could be added and deployed, in order to dynamically modify network nodes behavior. Applications can be developed with any language and communicate across heterogeneous environments, and across Internet and Intranet structures. At the deployment levelaswa uses an active node approach, and offers a controlled deployment mode. In terms of security, Authentication of deployed code and protection of the nodes is achieved by the use ofhttps and the header extensions of thesoap envelope. Finally to validate this architecture,aswa defines a Firewall as an Active Application to secure the code deployment.     

嵌入式因特网技术及其发展

介绍了嵌入式因特网技术的定义、兴起、实现方法及其应用,阐述了在嵌入式系统中实现因特网协议的方法以及EMIT、Web芯片和LonWorks等技术,并指出了嵌入式因特网技术需要解决的问题和发展方向.     

Formalized three-layer system-level model and reuse methodology forembedded data-dominated applications

In embedded data-dominated applications, a global system-level data transfer and storage exploration phase is crucial in obtaining a cost- and performance-efficient solution. We have developed a novel formalism to describe reusable blocks such that the essential part of the design exploration freedom is retained. This formalism is the basis for a system-level reuse methodology which allows reusing large parts of the design as heavily optimized structural VHDL or assembly code and describes the costly data access-related constructs at higher levels in the code hierarchy. Compared to a reuse approach based on fixed blocks, considerable power and area savings can be obtained, as demonstrated on real-life video and modem applications     

Programming Internet telephony services

Internet telephony enables a wealth of new service possibilities. Traditional telephony services such as call forwarding, transfer, and 800 number services, can be enhanced by interaction with e-mail, Web, and directory services. Additional media types, like video and interactive chat, can be added as well. One of the challenges in providing these services is how to effectively program them. Programming these services requires decisions regarding where the code executes, how it interfaces with the protocols that deliver the services, and what level of control the code has. In this article we consider this problem in detail. We develop requirements for programming Internet telephony services, and we show that at least two solutions are required-one geared for service creation by trusted users (such as administrators), and one geared for service creation by untrusted users (such as consumers). We review existing techniques for service programmability in the Internet and in the telephone network, and extract the best components of both. The result is a common gateway interface that allows trusted users to develop services, and the call processing language that allows untrusted users to develop services     

IoT–Cloud collaboration to establish a secure connection for lightweight devices

Internet of Things (IoT) technologies allow everyday objects including small devices in sensor networks to be capable of connecting to the Internet. Such an innovative technology can lead to positive changes in human life. However, if there is no proper security mechanism, private and sensitive data around humans can be revealed to the public Internet. In this aspect, this paper considers security issues of the IoT. In particular, we focus on various challenges in deploying Datagram Transport Layer Security (DTLS) protocol into a resource constrained environment. DTLS provides secure communication with UDP-based applications the same as TLS does for TCP-based applications. Several standard organizations such as IETF, oneM2M and OMA recommend using the DTLS as a default secure scheme for CoAP which is a new standard specified for resource-constrained environments. To find a practical way to deploy the DTLS in such a constrained IoT environments, we propose an IoT–Cloud collaboration system, where DTLS handshake delegation is the main component. We also implement and evaluate the proposed system in our real IoT testbed, where constrained devices are interconnected with each other in a multi-hop fashion. Evaluation results show that the proposed scheme dramatically reduces DTLS handshake latency, implementation code size and energy consumption.     

Dynamic memory management methodology applied to embedded telecom network systems

Presents a new methodology for dynamic memory management of embedded telecom network systems. This methodology enables the designer to further raise the abstraction level of the initial system specification and to achieve optimized embedded system designs. This methodology is well suited for systems characterized by a set of concurrent and dynamic processes, very high-bit-rate data streams, and intensive data transfer and storage, as encountered in telecom network applications. Up to now, it has been successfully applied to four telecom network systems. This methodology can be easily integrated into any C++-based system synthesis approach that bridges the gap between a concurrent process-level system specification and an optimized (for area, performance, or power) embedded implementation of communicating hardware/software processors. This is in contrast to current system design practice, where VHDL/C is derived without room for exploration, refinement, and verification, leading to expensive late design iterations. In this paper, the main focus lies on the system-level specification model and the dynamic memory management applied to two real-life telecom network systems.     

Nonintrusive TCP connection admission control for bandwidthmanagement of an Internet access link

We describe our approach to monitoring and managing the bandwidth of an Internet edge link with a view toward certain quality of service objectives for the services it carries. Such a link could be, for example, a campus's Internet access link or a small ISP's backbone access link. We use SNMP polls and packet snooping to obtain traffic statistics, and TCP admission control for bandwidth management. Our implementation is completely nonintrusive: we use Ethernet packet capture in the promiscuous mode for traffic analysis, and IP masquerading for blocking new TCP connections. This approach has been implemented by us in a software system for traffic management. We first justify our approach with a simple analytical model. We give an overview of our software implementation, and discuss some implementation issues. Then we provide measurement results that show the effectiveness of the techniques     

Memory-access-aware data structure transformations for embedded software with dynamic data accesses

Embedded systems are evolving from traditional, stand-alone devices to devices that participate in Internet activity. The days of simple, manifest embedded software [e.g. a simple finite-impulse response (FIR) algorithm on a digital signal processor (DSP] are over. Complex, nonmanifest code, executed on a variety of embedded platforms in a distributed manner, characterizes next generation embedded software. One dominant niche, which we concentrate on, is embedded, multimedia software. The need is present to map large scale, dynamic, multimedia software onto an embedded system in a systematic and highly optimized manner. The objective of this paper is to introduce high-level, systematically applicable, data structure transformations and to show in detail the practical feasibility of our optimizations on three real-life multimedia case studies. We derive Pareto tradeoff points in terms of accesses versus memory footprint and obtain significant gains in execution time and power consumption with respect to the initial implementation choices. Our approach is a first step to systematically applying high-level data structure transformations in the context of memory-efficient and low-power multimedia systems.     

Collaborative Web Computing: From Desktops to Webtops

The Web is advancing toward essentially a social network that transforms the Internet into a locus for all things social-data and applications. The Web is becoming a platform where people work, interact, share, and collaborate beyond the reach of office and desktop applications. This trend demands innovative technologies and applications that support people to work and collaborate seamlessly in both single-user desktop and multiuser Web environments. Such technologies make desktop applications Web-aware in that they can talk to Web servers using standard Web protocols     

基于低速处理器的功能最小化嵌入式Web服务器的设计

目前嵌入式Web服务器多使用专用集成电路(ASIC)技术或高速处理器实现，但嵌入式系统中大量存在的是技术较为成熟的低速处理器，基于低速处理器设计嵌入式Web服务器，市场前景非常广阔但技术难度较大。本提出了一种基于低速处理器的功能最小化Web服务器的设计方案，着重分析了HTTP协议的实现方法。     

Implicit admission control

Internet protocols currently use packet-level mechanisms to detect and react to congestion. Although these controls are essential to ensure fair sharing of the available resource between multiple flows, in some cases they are insufficient to ensure overall network stability. We believe that it is also necessary to take account of higher level concepts, such as connections, flows, and sessions when controlling network congestion. This becomes of increasing importance as more real-time traffic is carried on the Internet, since this traffic is less elastic in nature than traditional Web traffic. We argue that, in order to achieve better utility of the network as a whole, higher level congestion controls are required. By way of example, we present a simple connection admission control (CAC) scheme which can significantly improve the overall performance. This paper discusses our motivation for the use of admission control in the Internet, focusing specifically on control for TCP flows. The technique is not TCP specific, and can be applied to any type of flow in a modern IP infrastructure. Simulation results are used to show that it can drastically improve the performance of TCP over bottleneck links. We go on to describe an implementation of our algorithm for a router running the Linux 2.2.9 operating system. We show that by giving routers at bottlenecks the ability to intelligently deny admission to TCP connections, the goodput of existing connections can be significantly increased. Furthermore, the fairness of the resource allocation achieved by TCP is improved     

一种移动嵌入式Web服务器的接入方案

移动嵌入式Web服务器伴随着嵌入式技术与网络通信技术高速发展应运而生,是基于Internet的嵌入式技术网络化的扩展应用。本文先从三个方面对嵌入式Web技术的优点进行了分析,接着阐述了DDNS技术在移动嵌入式Web服务器的重要作用,然后对包含DDNS模块的通用嵌入式模块进行了说明,并对DDNS工作流程及报文结构进行分析,最后对基于移动嵌入式Web服务器的DDNS功能进行了简单验证,实验证明,该方案切实可行,稳定性好且成本低廉。本文既是对移动嵌入式Web服务器功能的增强,也是对动态IP嵌入式服务器接入Internet的关键技术分析,旨在建立一套移动移动嵌入式Web服务器的通用接入方案,具有一定的研究价值。