Characterization and concepts of time-frequency dissemination

Fundamental considerations that arise in designing a time or frequency dissemination system, are discussed and some dissemination methods are surveyed. A section on "Signal design for time and frequency dissemination" briefly summarizes radio propagation characteristics, discusses time signal format design, and considers how noise affects time and frequency signals. We point out fundamental techniques of time and frequency dissemination and describe similarities between systems for time dissemination and navigation. The use of synchronous satellite transponders and commercial television systems for time dissemination is emphasized because of their great promise. No attempt is made to cover every existing dissemination system; some systems are treated elsewhere in this Special Issue on Time Frequency. The concluding section gives three categories of users according to their required accuracy and shows typical systems which can provide desired accuracies. Various dissemination techniques are charted and evaluated in terms of salient characteristics such as accuracy, geographical coverage, cost factors, and others. To alleviate an existing frequency spectrum problem, we suggest that designers of communication and navigation systems consider opportunities for including time and frequency dissemination in their systems.     

Real traffic-data based evaluation of vehicular traffic environment and state-of-the-art with future issues in location-centric data dissemination for VANETs

Extensive investigation has been performed in location-centric or geocast routing protocols for reliable and efficient dissemination of information in Vehicular Adhoc Networks (VANETs). Various location-centric routing protocols have been suggested in literature for road safety ITS applications considering urban and highway traffic environment. This paper characterizes vehicular environments based on real traffic data and investigates the evolution of location-centric data dissemination. The current study is carried out with three main objectives: (i) to analyze the impact of dynamic traffic environment on the design of data dissemination techniques, (ii) to characterize location-centric data dissemination in terms of functional and qualitative behavior of protocols, properties, and strengths and weaknesses, and (iii) to find some future research directions in information dissemination based on location. Vehicular traffic environments have been classified into three categories based on physical characteristics such as speed, inter-vehicular distance, neighborhood stability, traffic volume, etc. Real traffic data is considered to analyze on-road traffic environments based on the measurement of physical parameters and weather conditions. Design issues are identified in incorporating physical parameters and weather conditions into data dissemination. Functional and qualitative characteristics of location-centric techniques are explored considering urban and highway environments. Comparative analysis of location-centric techniques is carried out for both urban and highway environments individually based on some unique and common characteristics of the environments. Finally, some future research directions are identified in the area based on the detailed investigation of traffic environments and location-centric data dissemination techniques.     

A Study of the Techniques of Automatic Abstracting and Knowledge Acquisition Systems

A Study of the Techniques of Automatic Abstracting and Knowledge Acquisition Systems     

Searching the Web: general and scientific information access

The World Wide Web has revolutionized the way people access information, and has opened up new possibilities in areas such as digital libraries, general and scientific information dissemination and retrieval, education, commerce, entertainment, government and health care. There are many avenues for improvement of the Web; for example, in the areas of locating and organizing information. Current techniques for access to both general and scientific information on the Web provide much room for improvement; search engines do not provide comprehensive indices of the Web and have difficulty in accurately ranking the relevance of results. Scientific information on the Web is very disorganized. We discuss the effectiveness of Web search engines, including results showing that the major Web search engines cover only a fraction of the “publicly indexable Web”. Current research into improved searching of the Web is discussed, including new techniques for ranking the relevance of results, and new techniques in metasearch that can improve the efficiency and effectiveness of Web search. The creation of digital libraries incorporating autonomous citation indexing is discussed for improved access to scientific information on the Web     

模拟集成电路设计工具的研究进展

介绍了模拟集成电路设计自动化工具的研究进展 ,详细叙述了有关模拟 IC设计自动化(DA)所用到的种种方法以及各种方法的优劣 ,提出了一些解决方案。介绍了模拟硬件描述语言(AHDLs)以及目前开发混合信号和混合层次 EDA的情况 ,最后叙述了所开发的基于知识的自动化器件产生器。器件产生器的设计思想有效地使用了电路模拟器和从它所得到的信息 ,且器件产生器自适应于工艺过程 ,因此既有基于模型设计系统的短设计时间 ,又有基于模拟设计系统的精确性 ,而且它提高了第一次投片成功率与设计周期之比。     

The moniT Project: Electromagnetic Radiation Exposure Assessment in Mobile Communications

The monIT project provides public information on population exposure to electromagnetic fields (EMF) from mobile communication systems in Portugal. The monitoring system is based on a network of autonomous remote probing stations, and also on an extensive EMF sounding program, both carried out in public areas across the country. Measured results are automatically uploaded to a Web site for public dissemination (http://www.lx.it.pt/monit), which also includes other relevant information about EMF for the general public. This paper describes the project's structure, the automatic monitoring system, the project's activities, and, finally, it presents a brief analysis of the measured results     

Real-Time Embedded Software Design for Mobile and Ubiquitous Systems

Currently available application frameworks that target at the automatic design of real-time embedded software are poor in integrating functional and non-functional requirements for mobile and ubiquitous systems. In this work, we present the internal architecture and design flow of a newly proposed framework called Verifiable Embedded Real-Time Application Framework (VERTAF), which integrates three techniques namely software component-based reuse, formal synthesis, and formal verification. The proposed architecture for VERTAF is component-based which allows plug-and-play for the scheduler and the verifier. The architecture is also easily extensible because reusable hardware and software design components can be added. Application examples developed using VERTAF demonstrate significantly reduced relative design effort, which shows how high-level reuse of software components combined with automatic synthesis and verification increases design productivity.     

Performance Analysis of Dielectric Resonator Antennas

Compact, lightweight and low cost electronics components are attracting much attention because of the rapid growth of the wireless communication systems. The antenna designers are thus in continuous search for new advanced design of miniaturized antennas. One solution is to use a dielectric resonator antenna (DRA) which provides various benefits in terms of the performance. This paper presents fundamental concepts, theory and review study carried out on DRAs. The achievable performance of DRAs designed for wide impedance bandwidth, low profiles, circular polarization, compactness, and high gain are illustrated. The latest techniques for improving the results are also covered.     

Sensor data fusion for an indoor and outdoor localization

Geolocation systems are constantly evolving to enhance the integrity, accuracy and availability. Today, the applications are emerging and multiplying which are parts of an overall context of mobility. In outdoor environments, GNSS systems used, such as GPS and Galileo, provide a good accuracy, but in the indoor environments, GNSS signal is deteriorated due to the signal degradation by different obstacles. Many techniques are used to locate users in the indoor environments such as Infrared, Ultrasound or Radiofrequency techniques. The use of these techniques facilitates the exchange and dissemination of information. This paper presents a new design of Indoor-Outdoor positioning system based on the combination of data from UWB and GPS sources.     

Knowledge-Based Aerial Image Understanding Systems and Expert Systems for Image Processing

This paper discusses roles of artificial intelligence in the automatic interpretation of remotely sensed imagery. We first discuss several image understanding systems for analyzing complex aerial photographs. The discussion is mainly concerned with knowledge representation and control structure in the aerial image understanding systems: a blackboard model for integrating diverse object detection modules, a symbolic model representation for three-dimensional object recognition, and integration of bottom-up and top-down analyses. Then, a model of expert systems for image processing is introduced that discusses which and what combinations of image processing operators are effective to analyze an image. Various information about image processing techniques is used to find efficient and reliable image analysis processes. In general, two kinds of knowledge, that is, knowledge about objects and about analysis tools (i. e., image processing techniques) are required to realize versatile photointerpretation systems.     

Blind adaptive interference suppression for direct-sequence CDMA

Direct sequence (DS) code division multiple access (CDMA) is a promising technology for wireless environments with multiple simultaneous transmissions because of several features: asynchronous multiple access, robustness to frequency selective fading, and multipath combining. The capacity of DS-CDMA systems is interference-limited and can therefore be increased by techniques that suppress interference. In this paper, we present developments in interference suppression using blind adaptive receivers that do not receive knowledge of the signal waveforms and propagation channels of the interference, and that require a minimal amount of information about the desired signal. The framework considered generalizes naturally to include additional capabilities such as receive antenna diversity. The most powerful application of the methods described here is for linearly modulated CDMA systems with short spreading waveforms (i.e., spreading waveforms with period equal to the symbol interval), for which they provide substantial performance gains over conventional reception. Implications for future system design due to the restriction of short spreading waveforms and directions for further investigation are discussed     

CAD tools for ASIC design

Computer aids have been used for both the design and verification of electronic systems for many years. The recent explosion in the complexity of electronic systems that the advent of Very Large Scale Integration (VLSI) has allowed, has made the use of sophisticated computer-aided design tools indispensable. Computer aids will soon also provide key proprietary advantages as semiconductor and system design houses vie for the promising Application-Specific IC (ASIC) market of the next decade. This paper focusses on the techniques critical to both custom and ASIC design, the directions of present research and development for these areas, and future trends. In particular, recent developments in tools for the automated design of combinational logic are reviewed. These techniques include both algorithmic and rule-based approaches.     

乳品企业原位清洗自动控制方案的实现

在调查国内乳品厂现状的基础上,借鉴从国外引进设备的乳品厂设计和使用经验,结合我国的实际情况,并融入若干年自控设计经验,综述了各工艺设备原位清洗自控方案、实现手段和方法。     

Architectures for ATM network survivability

This article surveys the restoration architectures for asynchronous transfer mode (ATM) network survivability that have been actively studied in this decade. Network reliability is critical for recent and future networks that will advance the information era. Moreover, it is one of the biggest factors in designing and managing networks. Since the early telecom network era, many restoration systems have been developed for plesiochronous digital hierarchy (PDH), synchronous digital hierarchy (SDH), synchronous optical network (SONET), leased lines and so on; and they were surveyed in many papers and books. This article focuses on new restoration techniques for ATM networks. First, the requirement studies are introduced. This includes the scant results published on the influence of failure and the state of failure analysis. Next, restoration schemes are categorized and briefly introduced. Examples include centralized control, automatic protection switch (APS), self-healing ring (SHR), self-healing network (SHN) and failure resistant virtual path (FRVP). In order to achieve adequate restoration probability with minimum cost, a network design scheme is necessary; thus, network design issues are introduced. Finally, this article focuses on the issues, future work, and problems that remain to be solved.     

Application of functional link neural network to HVAC thermaldynamic system identification

Recent efforts to incorporate aspects of artificial intelligence into the design and operation of automatic control systems have focused attention on techniques such as fuzzy logic, artificial neural networks and expert systems. The use of computers for direct digital control highlights the recent trend toward more effective and efficient heating, ventilating and air-conditioning (HVAC) control methodologies. Researchers in the HVAC field have stressed the importance of self-learning in building control systems and have encouraged further studies in the integration of optimal control and other advanced techniques into the formulation of such systems. Artificial neural networks can also be used to emulate the plant dynamics, in order to estimate future plant outputs and obtain plant input/output sensitivity information for online neural control adaptation. This paper describes a functional link neural network approach to performing the HVAC thermal dynamic system identification. Methodologies to reduce inputs of the functional link network to reduce the complexity and speed up the training speed are presented. Analysis and comparison between the functional link network approach and the conventional network approach for the HVAC thermal modeling are also presented     

说话人分割聚类研究进展

说话人分割聚类是近几年新兴起的语音信号处理研究方向,它主要研究如何确定连续语流中多说话人起止时间的位置,并标出每个语音段对应的说话人。这项研究对自动语音识别、多说话人识别和基于内容的音频分析等都具有重要的意义。根据说话人分割和聚类实现过程不同,本文从异步策略和同步策略的角度回顾了十年来国内外研究的主流算法、技术和代表系统,对比了不同代表系统在近几年NIST富信息转写评测的结果,最后讨论了目前还存在的问题,并对未来的发展进行了展望。      

Model-based design - Model misbehaviour

Model-based design can be big time-saver in developing complex systems. But, for safety-critical applications, it might be saving too much time - and in all the wrong places. Model-based design techniques are now firmly established in embedded design: particularly at the systems engineering level. From their roots in mathematical and algorithmic modeling, they have moved into the mainstream of product design, valued for their contribution to efforts to achieve results quickly - and reduce lead times and development costs. But the use of model-based design in dependable and mission critical systems raises a whole new raft of questions, particularly when it is combined with automatic code generation     

A New Criteria Decision Applied on the Primary Synchronization in the DS-WCDMA Interface of the UMTS System

In DS-WCDMA mobile systems such the UMTS, asynchronous cell site operation,assigning different long spreading code to each cell, yields the advantageof flexible system deployment. We can design an indoor system basedon an outdoor one. However, in general, much longer search time isrequired in asynchronous operation than in synchronous. This paperproposes three techniques to take decisions about synchronizationbased on observation of correlated signals. Classical decision criterialike maximum and threshold criterion are presented. A new decisioncriteria that we call Threshold&Max combined decision criteriais analyzed. The results of this new introduced technique is comparedwith the classical ones.     

Automatisierung und Autonomisierung

Trends and future in automation will be characterized by distributed sensors, being wirelessly connected. Shape memory alloys and even concepts of shape control will influence actuator concern. The multitude of operational possibilities increases exponentially with the number of units used in automatic control systems. Virtual systems will be important, design will include reliability, maintainance, economic problems and sustainability. A high number of methods will be incorporated in automation known as the very spread topic of today’s artificial intelligence. Automation will be characterized by humanoid properties and will be more close to biological systems. The design methods in automatic control and computer engineering will be merged. Soft and associative computing and memories as well as multi-agent techniques will be very common. One has to emphasize impact on man, society and environment.     

Routing techniques in wireless sensor networks: a survey

Wireless sensor networks consist of small nodes with sensing, computation, and wireless communications capabilities. Many routing, power management, and data dissemination protocols have been specifically designed for WSNs where energy awareness is an essential design issue. Routing protocols in WSNs might differ depending on the application and network architecture. In this article we present a survey of state-of-the-art routing techniques in WSNs. We first outline the design challenges for routing protocols in WSNs followed by a comprehensive survey of routing techniques. Overall, the routing techniques are classified into three categories based on the underlying network structure: flit, hierarchical, and location-based routing. Furthermore, these protocols can be classified into multipath-based, query-based, negotiation-based, QoS-based, and coherent-based depending on the protocol operation. We study the design trade-offs between energy and communication overhead savings in every routing paradigm. We also highlight the advantages and performance issues of each routing technique. The article concludes with possible future research areas.