A Metadata Design for Augmented Broadcasting and Testbed System Implementation

Augmented reality (AR) is a popular service in mobile devices, and many AR applications can be downloaded from app stores. As TV broadcasting has continued to integrate with the Internet, it has become an area in which the AR concept is able to reside, although in a simple form, such as an advertisement placed in the static region of a scene. There are some restrictions against TV broadcasting realizing AR since TVs are fixed devices and typically do not have GPS, geomagnetic, or acceleration sensors, which are standard equipment in mobile devices. However, the desire to experience AR on a large TV screen has triggered research and development for an ideal AR business model and service type. This paper introduces several use cases for augmented broadcasting services and also presents an augmented broadcasting metadata scheme designed for a broadcasting environment. We also verify some of the use cases and an augmented broadcasting metadata scheme in an implemented augmented broadcasting system based on a hybrid TV platform.     

Intrusion Detection Routers: Design, Implementation and Evaluation Using an Experimental Testbed

In this paper, we present the design, the implementation details, and the evaluation results of an intrusion detection and defense system for distributed denial-of-service (DDoS) attack. The evaluation is conducted using an experimental testbed. The system, known as intrusion detection router (IDR), is deployed on network routers to perform online detection on any DDoS attack event, and then react with defense mechanisms to mitigate the attack. The testbed is built up by a cluster of sufficient number of Linux machines to mimic a portion of the Internet. Using the testbed, we conduct real experiments to evaluate the IDR system and demonstrate that IDR is effective in protecting the network from various DDoS attacks.     

无线传感执行器网络双射频通信节点设计与实现

针对无线传感器执行器网络拓扑结构动态变化、通信量大、实时性强及协同工作等特点,同时为降低通信时的信号干扰,设计并实现了一种基于IEEE 802.15.4的双射频多信道通信节点。对关键的天线电路进行了分析和设计;开发了通信模块与控制决策中心的USART接口程序和双通信芯片间的I2C接口程序。     

一种经济型嵌入式工业网关的设计与实现

为适应工业现场总线的现状和工业网关的需求,基于对现场传输的信息量和速度的考虑,设计了一种基于51系列单片机的多总线接口的经济型嵌入式工业网关,满足现场实时性和可靠性要求,实现了“管控一体化”。分析了系统的软件实现,鉴于现场传输信息的复杂性,仅以立即传输的信息为例,给出了CAN和以太网协议转换流程图。     

Design of a Web Based Underwater Acoustic Communication Testbed and Simulation Platform

Wireless Personal Communications - Underwater Wireless Sensor Networks (UWSNs) are playing a vital role in exploring the unseen underwater (UW) natural resources. However, performance evaluation of...     

Modeling Communication Networks With Hybrid Systems

This paper introduces a general hybrid systems framework to model the flow of traffic in communication networks. The proposed models use averaging to continuously approximate discrete variables such as congestion window and queue size. Because averaging occurs over short time intervals, discrete events such as the occurrences of a drop and the consequent reaction by congestion control can still be captured. This modeling framework, thus, fills a gap between purely packet-level and fluid-based models, faithfully capturing the dynamics of transient phenomena and yet providing significant flexibility in modeling various congestion control mechanisms, different queueing policies, multicast transmission, etc. The modeling framework is validated by comparing simulations of the hybrid models against packet-level simulations. It is shown that the probability density functions produced by the ns-2 network simulator match closely those obtained with hybrid models. Moreover, a complexity analysis supports the observation that in networks with large per-flow bandwidths, simulations using hybrid models require significantly less computational resources than ns-2 simulations. Tools developed to automate the generation and simulation of hybrid systems models are also presented. Their use is showcased in a study, which simulates TCP flows with different roundtrip times over the Abilene backbone.     

The Implementation of an Amplitude-Locked Loop for Digital Communication Chip Design

The purpose of a communication system is to transmit an information-bearing message signal through a channel that separates a transmitter from a receiver. The modulated carrier is often induced and interfered with by various noise sources. The co-channel separation system is a demodulation process function that operates at the same carrier modulation system. Here, we adopted the field-programmable gate array (FPGA) design platform configuration to develop, implement and achieve co-channel separation for an amplitude-locked loop demodulation chip-design digital system with additive white Gaussian noise interference. In this paper, the compact reconfigurable I/O built-in FPGA chip system is integrated and applied to obtain the cross-field relevant integration function for communication and chip-design system via programming in a graphical language. Additionally, the FPGA chip-design system runs all of the program code in hardware and provides high reliability and determinism. This cross-field ideal is adopted to save time and reduce complexity in the design development of a custom circuitry system. The FPGA chip-design system described in this paper is also used to achieve a digital communication chip prototype design model, followed by presentation of the steps necessary for building and program verification. The communication and chip-design concept may provide very useful physical applications for the industry.     

Development of a Scaled Vehicle With Longitudinal Dynamics of an HMMWV for an ITS Testbed

This paper applies Buckingham's pi theorem to the problem of building a scaled car whose longitudinal and power-train dynamics are similar to those of a full-size high-mobility multipurpose wheeled vehicle (HMMWV). The scaled vehicle uses hardware-in-the-loop (HIL) simulation to capture some of the scaled HMMWV dynamics physically, and simulates the remaining dynamics onboard in real time. This is performed with the ultimate goal of testing cooperative collision avoidance algorithms on a testbed comprising a number of these scaled vehicles. Both simulation and experimental results demonstrate the validity of this HIL-based scaling approach.     

基于FTTx的下一代通信网精确覆盖系统的设计与实现

在"宽带中国"上升为国家战略的大背景下,有效支撑移动宽带和固定宽带业务的发展是当前及今后一段时期通信网络转型的一项重大举措,也是室内深度覆盖建设转型的契机。通过探讨基于FTTx的下一代通信网精确覆盖系统的设计、系统基本原理、硬件电路原理及系统硬件实现等方面,为各运营商在无线网室内精确覆盖方案的制定提供一定的参考。     

基于Java的通信中间件的设计与实现

通过研究通信软件中常用的设计算法,收集使用面向对象技术开发通信软件时常用的设计模式,利用Java语言完成基于Java的通信中间件设计与实现,并给出了主要部分的实现。实现了全部的JMS标准API,提供了消息持久化、消息预览和消息选择功能,建立了可靠的线级通讯连接,提高了产品的服务质量。     

一种串口多机应答式通信协议的设计与实现

分析了串口多机应答式通信中存在的传输丢失和传输误码故障的产生源.设计出了一种简单可靠的多机应答式通信协议,实现了传输差错控制,在数据帧传输阶段能够实现可靠的协议通信.本协议在调频广播发射机微机控制器中成功应用.     

On the Decomposition of Large Communication Networks for Hierarchical Control Implementation

In the implementation of hierarchical schemes for the adaptive control of large communication networks, decomposition of the overall network into node clusters and assignment of a supervisor for each cluster are of central importance. A formulation of the decomposition problem as a mathematical optimization problem is given and an algorithm for solution is presented.     

分布式虚拟环境中网络通信软件的设计及其实现

网络通信是分布式虚拟环境设计中的重要技术，本文介绍了网络通信软件的设计思想、总体结构及其实现的关键技术。     

本科生班导师管理系统设计与实现

针对本科学生各种信息和数据过多,班导师难以短时间内统计和快速查找的问题,文章编写了一个本科生管理信息系统,以减少导师的工作量。该系统能快速准确地帮助导师查找学生信息,并统计、分析一些相关数据。     

Mobility Testbed for 3GPP2-Based Multimedia Domain Networks

Wireless service providers strive to preserve the quality of service and user experience for mobile users. Several standards bodies are defining architectures that can be used as a platform to provide secure and seamless services to these mobile users. These architectures aim to provide several required functions such as signaling, configuration, security association, encryption, and billing. However, the placement of several functional components and their interaction at several layers contributes to the operational complexity and thus affects the optimal results. Testbed realization of any standardized architecture can help investigate the underlying networking issues. In this article, we describe a mobility test bed implementation based on one of the architecture alternatives of 3GPP2, where the outbound signaling servers are distributed around the edges of the network. We experiment with three different hand-off techniques and analyze the associated experimental results. Analysis of these experimental results and experiences obtained from the testbed implementation can be helpful to any service provider that plans to deploy a version of the MMD (multimedia domain) architecture with distributed signaling servers.     

Reliability Indices for Topological Design of Computer Communication Networks

Incorporating network reliability parameter in the design of reliable computer communication networks makes the computations prohibitive. Interdependence among network topological parameters does not permit the design of a maximally reliable network using any one of the parameters and thus, there arises a real need for a composite reliability index which gives a more realistic assessment of network reliability. After discussing experimental results regarding the effects of various topological parameters on network reliability, we present two heuristic reliability indices which give a fair indication of overall reliability. A design procedure for reliable computer communication network based on local search technique incorporating these reliability indices is suggested. Having only one composite reliability index which is very simple to evaluate saves computation while designing maximally reliable computer networks as compared to the existing techniques based on several reliability measures.     

Design and Analysis of an Efficient Communication Strategy for Hierarchical and Highly Changing Ad-hoc Mobile Networks

In this work we introduce two practical and interesting models of ad-hoc mobile networks: (a) hierarchical ad-hoc networks, comprised of dense subnetworks of mobile users interconnected by a very fast yet limited backbone infrastructure, (b) highly changing ad-hoc networks, where the deployment area changes in a highly dynamic way and is unknown to the protocol. In such networks, we study the problem of basic communication, i.e., sending messages from a sender node to a receiver node. For highly changing networks, we investigate an efficient communication protocol exploiting the coordinated motion of a small part of an ad-hoc mobile network (the runners support) to achieve fast communication. This protocol instead of using a fixed sized support for the whole duration of the protocol, employs a support of some initial (small) size which adapts (given some time which can be made fast enough) to the actual levels of traffic and the (unknown and possibly rapidly changing) network area, by changing its size in order to converge to an optimal size, thus satisfying certain Quality of Service criteria. Using random walks theory, we show that such an adaptive approach is, for this class of ad-hoc mobile networks, significantly more efficient than a simple non-adaptive implementation of the basic runners support idea, introduced in [9,10]. For hierarchical ad-hoc networks, we establish communication by using a runners support in each lower level of the hierarchy (i.e., in each dense subnetwork), while the fast backbone provides interconnections at the upper level (i.e., between the various subnetworks). We analyze the time efficiency of this hierarchical approach. This analysis indicates that the hierarchical implementation of the support approach significantly outperforms a simple implementation of it in hierarchical ad-hoc networks. Finally, we discuss a possible combination of the two approaches above (the hierarchical and the adaptive ones) that can be useful in ad-hoc networks that are both hierarchical and highly changing. Indeed, in such cases the hierarchical nature of these networks further supports the possibility of adaptation.     

SWiMNet: A Scalable Parallel Simulation Testbed for Wireless and Mobile Networks

We present a framework, called SWiMNet, for parallel simulation of wireless and mobile PCS networks, which allows realistic and detailed modeling of mobility, call traffic, and PCS network deployment. SWiMNet is based upon event precomputation and a combination of optimistic and conservative synchronization mechanisms. Event precomputation is the result of model independence within the global PCS network. Low percentage of blocked calls typical for PCS networks is exploited in the channel allocation simulation of precomputed events by means of an optimistic approach.Various experiments were conducted to study the performance and scalability of SWiMNet using a realistic mobility model and executed on a cluster of workstations. Experimental results indicate that our parallel simulation model yields good speedup, and significantly reduces the execution time compared to a sequential implementation. Finally, an analytical study of our PCS simulation model is also presented and compared with the experimental results. Our model is found to be consistent with the analytical study.     

UAVS通信协议模块的设计与实现

在现代局部战争中,可采用高空长航时无人机作为通信中继平台,实现地面站与各任务机之间的通信(测控信息和任务信息传输)。论文给出了无人机系统(UAVS)通信网仿真模块的组成,设计了通信协议模块的分层呼叫、数据传输和飞行控制命令三个协议流程,该软件已成功地用于UAVS通信网仿真系统。     

多重加密通信系统的设计与实现

为实现无线信道中的高度保密通信,提出了一种基于DSP平台的多重加密通信系统。加密通信终端以高性能数字信号处理器DSP芯片为核心,融合高级加密算法（AES）、非对称加密算法（RSA）和混沌伪随机序列CPRS（Chaos Pseudo-Random Sequence）三种加密算法,利用电路交换数据业务（CSD）信道进行语音保密通信。文中详细阐述了系统方案的总体框架设计,介绍了系统硬件平台选型及相关硬件和外围接口的设计,并结合系统功能和保密体系,具体描述了系统的软件设计以及总体工作流程。实验结果表明：三层加密算法安全可靠,语音传输延时很小,实现了良好的保密通信目的。