Supporting Service Discovery,Querying and Interaction in Ubiquitous Computing Environments

In this paper, we contend that ubiquitous computing environments will be highly heterogeneous, service rich domains. Moreover, future applications will consequently be required to interact with multiple, specialised service location and interaction protocols simultaneously. We argue that existing service discovery techniques do not provide sufficient support to address the challenges of building applications targeted to these emerging environments.This paper makes a number of contributions. Firstly, using a set of short ubiquitous computing scenarios we identify several key limitations of existing service discovery approaches that reduce their ability to support ubiquitous computing applications. Secondly, we present a detailed analysis of requirements for providing effective support in this domain. Thirdly, we provide the design of a simple extensible meta-service discovery architecture that uses database techniques to unify service discovery protocols and addresses several of our key requirements. Lastly, we examine the lessons learnt through the development of a prototype implementation of our architecture.     

Centaurus: An Infrastructure for Service Management in Ubiquitous Computing Environments

In the near future, we will see dramatic changes in computing and networking hardware. A large number of devices (e.g., phones, PDAs, even small household appliances) will become computationally enabled. Micro/nano sensors will be widely embedded in most engineered artifacts, from the clothes we wear to the roads we drive on. All of these devices will be (wirelessly) networked using Bluetooth, IEEE 802.15 or IEEE 802.11 for short range connectivity creating pervasive environments. In this age where a large number of wirelessly networked appliances and devices are becoming commonplace, there is a necessity for providing a standard interface to them that is easily accessible by any user. This paper outlines the design of Centaurus, an infrastructure for presenting services to heterogeneous mobile clients in a physical space via some short range wireless links. The infrastructure is communication medium independent; we have implemented the system over Bluetooth, CDPD and Infrared, three well-known wireless technologies. All the components in our model use a language based on Extensible Markup Language (XML) for communication, giving the system a uniform and easily adaptable interface. Centaurus defines a uniform infrastructure for heterogeneous services, both hardware and software, to be made available to diverse mobile users within a confined space.     

异构个人域网络中的服务发现机制

个人周边智能设备与移动业务的融合促进了服务发现机制的发展,智能设备的增加和移动性也使得现有服务发现机制很难在用户移动当中始终提供有效服务。在对个人周边的异构网络特征分析的基础上,利用组播和信息熔合等技术,提供了一套适用于节点具有群组移动性、异构性的动态网络的可靠的服务发现机制,并且不会消耗过多的系统带宽资源。     

Assessing Level of Ubiquitous Computing Services for Ubiquitous Business Design

We are entering into a new era of enterprise computing that is characterized by an emphasis on broadband convergence, knowledge sharing, and calm services. Some people refer to this as the "ubiquitous network" business model because its focus is on a high degree of connectivity between a company and its customers, suppliers, and channel partners. Moreover, immediate access to ideas, goods, and services will be of greater value than the traditional model of permanent and ponderous possession. This paper illustrates how ubiquitous computing technology can be combined with legacy computer-based information systems, along with thoughts on relevant issues of ubiquitous commerce. We also propose a model for how to assess levels of ubiquitous computing services.     

Context‐Aware Active Services in Ubiquitous Computing Environments

With the advent of ubiquitous computing environments, it has become increasingly important for applications to take full advantage of contextual information, such as the user's location, to offer greater services to the user without any explicit requests. In this paper, we propose context‐aware active services based on context‐aware middleware for URC systems (CAMUS). The CAMUS is a middleware that provides context‐aware applications with a development and execution methodology. Accordingly, the applications based on CAMUS respond in a timely fashion to contextual information. This paper presents the system architecture of CAMUS and illustrates the content recommendation and control service agents with the properties, operations, and tasks for context‐aware active services. To evaluate CAMUS, we apply the proposed active services to a TV application domain. We implement and experiment with a TV content recommendation service agent, a control service agent, and TV tasks based on CAMUS. The implemented content recommendation service agent divides the user's preferences into common and specific models to apply other recommendations and applications easily, including the TV content recommendations.     

Service Discovery in Agent-Based Pervasive Computing Environments

Directory based service discovery mechanisms are unsuitable for ad-hoc m-commerce environments. Working towards finding an alternate mechanism, we developed Allia: a peer-to-peer caching based and policy-driven agent-service discovery framework that facilitates cross-platform service discovery in ad-hoc environments. Our approach achieves a high degree of flexibility in adapting itself to changes in ad-hoc environments and is devoid of common problems associated with structured compound formation in mobile commerce environments. Device capabilities and limitations, user preferences regarding device usage, application specifics with respect to mobile commerce are factors that our framework adapts to. We have described our initial implementation of Allia over ThinkPads and iPAQs by extending the LEAP Agent Platform and using Bluetooth as the underlying network protocol. In addition, we evaluated Allia's performance by running simulations of our protocol in Glomosim simulator. We also compared our framework against a structured compound-based architecture.     

Strategic Implications for E-Business Organizations in the Ubiquitous Computing Economy

The ubiquitous economy brings both pros and cons for the organizations. The third space emerged by the development of ubiquitous computing generates new concept of community. The community is tightly coupled with people, products, and systems. Organizational strategies need to be reshaped for the changing environment in the third space and community. Organizational structure also needs to change for community serving organization. Community serving concept equipped with the standardized technology will be essential. One of the key technologies, RFID service will play a key role to acknowledge identification and services required. When the needs for sensing the environment increase, technological requirement such as the ubiquitous sensor network (USN) will be critically needed..     

普适计算中定位服务的参考点选择及误差分析

通过分析多边定位法在未知节点的定位过程中产生的定位误差,提出并证明了有关定位参考点布置的三个定理,使在普适计算环境中可通过有针对性地布置参考点的位置来减小未知节点的定位误差.在此基础上提出定位参考点选择算法,该算法以参考点间的位置关系为基础,通过选择合适的参考点对未知节点进行定位.仿真实验结果表明所提出的定位参考点布置定理及选择算法能满足普适计算环境中移动对象实时定位的需求,并具有较高的定位精度.     

普适计算中定位服务的参考点布置及选择算法

如何准确地获得未知移动节点的位置信息是普适计算环境下定位服务要解决的关键问题.本文通过分析多边形定位法在定位过程中产生的定位误差,将混沌动力学的三大特性很好地运用到参考点的摆放问题上,提出并证明了定位参考点布置的三个定理.在此基础上,对传统多边形定位算法进行了改进,提出了定位参考点选择算法.仿真实验表明本文所提出的参考点布置定理及定位参考点选择算法能更好地满足对普适终端实时定位的需求,且具有较高的定位精度.     

基于OWL-S的服务发现语义匹配机制

 本文提出一种基于OWL-S的语义web服务匹配系统的机制,将语义元素引入UDDI系统中,从而在UDDI中保存语义信息.系统通过语义服务匹配算法提高web服务匹配的准确度和召回率,并通过数据映射机制保证模型对于当前的服务发现标准UDDI基础架构的兼容以及UDDI标准操作接口的透明性.系统使用本体概念的索引机制提高服务发现的效率.而且,系统在建立和维护索引的过程、或服务的匹配过程中使用近似概念搜寻算法进一步提高本体概念搜寻和服务匹配的效率.     

基于泛在网络的资源发现与监控模型的研究

泛在网络是一个开放的巨复杂系统,泛在网络环境中的资源具有广域分布、自治、异构、动态等特性,如何对泛在网络资源进行有效的管理以满足用户的需求是一个极具挑战性的问题.文中结合移动Agent技术提出了一种新的泛在网络资源发现与监控模型.详细介绍了它的总体框架.工作机制,并给出了性能评价.     

UbiqMuseum: A Bluetooth and Java Based Context-Aware System for Ubiquitous Computing

This paper evaluates the use of Bluetooth and Java based technologies in ubiquitous computing environments. Ubiquitous computing strongly depends on leveraging appropriate contextual information to users, according to their preferences and the environment in which they reside. We present UbiqMuseum – an experimental context-aware application that provides context-aware information to museum visitors. UbiqMuseum combines the productivity of Java with the universal connectivity provided by Bluetooth wireless technology. We describe the overall architecture and discuss the implementation steps taken to create our Bluetooth and Java based context-aware application. We demonstrate practicality of building a context-aware system by using UbiqMuseum as a proof of concept that integrates a combination of Bluetooth, WLAN and Ethernet LAN technologies. Finally we run some experiments in a small testbed to evaluate the performance and system behaviour. We evaluate the impact on throughput with varying packet size, coding types and device separation distance sending both images and text. We also present our findings in term of inquiry delay with respect to distance. Numerical results show that Bluetooth offers a relatively steady throughput up to 10 m while the inquiry delay does not increase significantly with distance. Juan-Carlos Cano is an assistant professor in the Department of Computer Engineering at the Polytechnic University of Valencia (UPV) in Spain. He earned an M.Sc. and a Ph.D. in computer science from the UPV in 1994 and 2002 respectively. Between 1995–1997 he worked as a programming analyst at IBM's manufacturing division in Valencia. His current research interests include power aware routing protocols for mobile ad hoc networks and pervasive computing. You can contact him at jucano@disca.upv.es. Pietro Manzoni received the MS degree in computer science from the “Universitá degli Studi" of Milan, Italy, in 1989, and the Ph.D. degree in computer science from the Polytechnic University of Milan, Italy, in 1995. He is an associate professor of computer science at the Polytechnic University of Valencia, Spain. His research activity is related to wireless networks protocol design, modeling, and implementation. He is member of the IEEE. C.-K. Toh is currently a Professor and Chair in Communication Networks at Queen Mary University of London, UK. He is also the Director of the UK Ad Hoc Wireless Consortium and Director of the Queen Mary/Fudan Joint Research Lab in Mobile Networking and Ubiquitous Computing. Concurrently, he is also an Honorary Professor with the University of Hong Kong and an Adjunct Professor at Fudan University, Shanghai. Previously, he was the Director of Research with TRW Tactical Systems in California, USA (now Northrop Grumman Corporation) and was responsible for DARPA and Army programs in communications and networking. He had also worked for Hughes Research, ALR, HP, and was a professor at GeorgiaTech and University of California, Irvine. CK is the recipient of the 2005 IEEE Kiyo Tomiyasu Technical Medal Award, for “pioneering contributions to communication protocols in ad hoc mobile wireless networks." He is the author of “Wireless ATM & Ad Hoc Networks" (Kluwer Press, 1996) and “Ad Hoc Mobile Wireless Networks" (Prentice Hall Engineering Title Best Seller, 2001–2003). He is a recipient of the ACM Recognition of Service Award, for co-founding ACM MobiHoc Conference. He is a co-recipient of the Korean Science & Engineering Foundation Best Journal paper Award for his work on ad hoc TCP. CK was formerly the Chairman of IEEE Communications Society Technical Committee on Computer Communications and Chairman of IEEE Subcommittee on Ad Hoc Mobile Wireless Networks. He was an IEEE Expert/Distinguished Lecturer and had served as a Steering Committee Member for IEEE WCNC Conference and IEEE Transaction on Mobile Computing. He was a member of IEEE Communications Society Meetings & Conferences Board. CK was an editor for IEEE Networks, IEEE JSAC, IEEE transactions on Wireless Communications, Journal on Communication Networks, and IEEE Distributed Systems. He is a Fellow of four societies: British Computer Society, the IEE, the Hong Kong Institution of Engineers and the New Zealand Computer Society. He received his Ph.D. degree in Computer Science from Cambridge University, England, and his executive education from Harvard.     

Smart Identification Frameworks for Ubiquitous Computing Applications

We present our results of the conceptual design and the implementation of ubiquitous computing applications using smart identification technologies. First, we describe such technologies and their potential application areas, then give an overview of some of the applications we have developed. Based on the experience we have gained from developing these systems, we point out design concepts that we have found useful for structuring and implementing such applications. Building upon these concepts, we have created two frameworks based on Jini (i.e., distributed Java objects) and Web Services to support the development of ubiquitous computing applications that make use of smart identification technology. We describe our prototype frameworks, discuss the underlying concepts and present some lessons learned.     

A Time‐Constrained Information Processing Model in Ubiquitous Environments

As pervasive computing is widely adopted and reliable networks are becoming more easily accessible, there is a rapidly growing need to develop a mechanism to analyze and evaluate the performance of ubiquitous environments. This paper presents an information processing model which characterizes a ubiquitous environment where a variety of pieces of information need to be exchanged among devices within a system. The proposed model not only provides analytical tools to evaluate the performance of devices, but also makes it possible to identify key factors in designing a ubiquitous environment. For illustrative purposes, a test bed is constructed and the performance of the system is assessed based on the proposed model.     

异构环境下语义Web服务发现算法研究

随着网络上越来越多种类各异的Web服务,如何对其进行有效发现是实现动态Web服务组合的关键.本文研究了异构环境下服务发现语义信息的匹配问题,利用领域本体解决了异构数据的综合利用与共享,并通过实验表明了本文提出方法的有效性.     

Towards a Ubiquitous Robotic Companion: Design and Implementation of Ubiquitous Robotic Service Framework

In recent years, motivated by the emergence of ubiquitous computing technologies, a new class of networked robots, ubiquitous robots, has been introduced. The Ubiquitous Robotic Companion (URC) is our conceptual vision of ubiquitous service robots that provide users with the services they need, anytime and anywhere in ubiquitous computing environments. To realize the vision of URC, one of the essential requirements for robotic systems is to support ubiquity of services: that is, a robot service must be always available even though there are changes in the service environments. Specifically robotic systems need to be automatically interoperable with sensors and devices in current service environments, rather than statically preprogrammed for them. In this paper, the design and implementation of a semantic‐based ubiquitous robotic space (SemanticURS) is presented. SemanticURS enables automated integration of networked robots into ubiquitous computing environments exploiting Semantic Web Services and AI‐based planning technologies.     

基于混合语义相似度的服务匹配方法

服务匹配已经成为服务计算领域的一大热点.合理的服务匹配算法可以帮助服务需求者寻找到满足自己需求的服务.在分析现有的服务算法基础上,提出基于混合语义相似度服务匹配方法MSSMA（Mix Semantic Similarity Matching Algorithm）.将比较成熟的语义相似度算法和基于匹配等级的计算方法相结合,从而提高服务匹配的精度.     

基于概念语义协商的服务Agent划分

 服务参与者Agent之间使用异构的私有本体概念构造消息并进行交互,会由于消息语义的错误理解而影响服务发现的效率和结果的准确性.提出使用概念语义协商的方法改善服务Agent之间的理解能力;定义了服务Agent模型和本体概念解释元组,设计了服务Agent协商行为原语以及协商请求和响应协议;根据概念语义协商结果对私有本体进行更新并根据本体概念理解的相似度对参与服务的Agent进行划分,使功能相近且能互相理解的Agent处于相同的服务社区.实验表明,通过语义协商的服务Agent划分方法,能够有效提高同一服务社区服务Agent之间的概念理解程度,在协商概念数为2和8时,该方法较其他方法能够将概念理解错误率减少平均大约30%.     

PosCFS+: A Self‐Managed File Service in Personal Area Network

Wearable computers consisting of various small devices such as smart phones, digital cameras, MP3 players and specialized I/O devices in personal area networks will play an important role in future ubiquitous computing. In this environment, accessing user data is quite complex due to the dynamic and heterogeneous characteristics of the underlying networks. Moreover, since the amount of user data increases rapidly, automatic data backup management is also critical. To overcome these challenges, several studies have been conducted including our previously proposed file service system, PosCFS, which could be adapted to the requirements with a virtualization technique allowing per‐user global namespace for managing and accessing data stored on physical storage spaces detected in PAN. In this paper, we present a smart file service framework, PosCFS+ which is an improved and extended version of our previous work. Performance improvement is made possible by redesigning the metadata management scheme based on database and keywords rather than ontology. In addition, the automatic data replication management is newly designed based on the OSD protocol.     

Service Composition for Mobile Environments

Service Composition, that is, the development of customized services by discovering, integrating and executing existing services has received a lot of attention in the last couple of years with respect to wired-infrastructure or Internet web services. With the advancement in the wireless technology and rapid deployment of mobile devices, we envision that in the near future wirelessly connected mobile devices in a given vicinity will also provide services that can be leveraged in the composition process. This is particularly true of what have been described as “pervasive computing” environments. However, wired-infrastructure based service composition architectures are not designed to consider the various factors like mobility, device heterogeneity, resource variability and reliability in a mobile environment. In this paper, we describe the issues related to service composition in mobile environments and evaluate criteria for judging protocols that enable such composition. We present a distributed architecture and associated protocols for service composition in mobile environments that take into consideration mobility, dynamic changing service topology and device resources. The composition protocols are based on distributed brokerage mechanisms and utilize a distributed service discovery process over ad-hoc network connectivity. We present simulation results of our protocols, and compare them with a centralized service composition protocol traditionally used for wired-infrastructure environments. The results show that our approach clearly outperforms the existing centralized approaches, and that our protocols are able to adapt and better utilize the changing service topology and resources in a mobile environment.This work is supported in part by NSF awards 9875433 and 0070802, DARPA DAML program and IBM. Dipanjan Chakraborty is a Ph.D candidate and a research member of ebiquity research group at University of Maryland, Baltimore County (UMBC). His reserach is in the areas of mobile and pervasive computing environments, mobile and e-commerce, peer-to-peer systems with special interests in the fields of service discovery, information aggregation and composition, ad-hoc network application-centric routing, agent-based systems. He specializes in the development and modeling of distributed architectures to enable mobile and pervasive commerce in ubiquitous environments. His thesis is in the area of service discovery and composition for pervasive environments. He has been a fellow of IBM during the 3 years of his Ph.D candidacy. Anupam Joshi is an Associate Professor of Computer Science and Electrical Engineering at UMBC. Earlier, he was an Assistant Professor in the CECS department at the University of Missouri, Columbia. He obtained a B. Tech degree in Electrical Engineering from IIT Delhi in 1989, and a Masters and Ph.D. in Computer Science from Purdue University in 1991 and 1993 respectively. His research interests are in the broad area of networked computing and intelligent systems. His primary focus has been on data management for mobile computing systems in general, and most recently on data management and security in pervasive computing and sensor environments. He has created agent based middleware to support discovery, composition, and secure access of services/data over both infrastructure based (e.g. 802.11, cellular) and ad-hoc wireless networks (e.g. Bluetooth). He is also interested in Semantic Web and Data/Web Mining, where he has worked on personalizing the web space using a combination of agents and soft computing. His other interests include networked HPCC. He has published over 50 technical papers, and has obtained research support from NSF, NASA, DARPA, DoD, IBM, AetherSystens, HP, AT&T and Intel. He has presented tutorials in conferences, served as guest editor for special issues for IEEE Personal Comm., Comm. ACM etc., and served as an Associate Editor of IEEE Transactions of Fuzzy Systems from 99-03. At UMBC, Joshi teaches courses in Operating Systems, Mobile Computing, Networking, and Web Mining. He is a member of IEEE, IEEE-CS, and ACM. Tim Finin is a Professor in the Department of Computer Science and Electrical Engineering at the University of Maryland Baltimore County (UMBC). He has over 30 years of experience in the applications of Artificial Intelligence to problems in information systems, intelligent interfaces and robotics and is currently working on the theory and applications of intelligent software agents, the semantic web, and mobile computing. He holds degrees from MIT and the University of Illinois. Prior to joining the UMBC, he held positions at Unisys, the University of Pennsylvania, and the MIT AI Laboratory. Finin is the author of over 180 refereed publications and has received research grants and contracts from a variety of sources. He has been the past program chair or general chair of several major conferences. He is a former AAAI councilor and is a member of the the board of directors of the Computing Research Association. Yelena Yesha received the B.Sc. degree in Computer Science from York University, Toronto, Canada in 1984, and the M.Sc. and Ph.D degrees in Computer and Information Science from The Ohio State University in 1986 and 1989, respectively. Since 1989 she has been with the Department of Computer Science and Electrical Engineering at the University of Maryland Baltimore County, where she is presently a Verizon Professor. In addition, from December, 1994 through August, 1999 Dr. Yesha served as the Director of the Center of Excellence in Space Data and Information Sciences at NASA. Her research interests are in the areas of distributed databases, distributed systems, mobile computing, digital libraries, electronic commerce, and trusted information systems. She published 8 books and over 100 refereed articles in these areas. Dr. Yesha was a program chair and general co-chair of the ACM International Conference on Information and Knowledge Management and a member of the program committees of many prestigious conferences. She is a member of the editorial board of the Very Large Databases Journal, and the IEEE Transaction on Knowledge and Data Engineering, and is editor-in-chief of the International Journal of Digital Libraries. During 1994, Dr. Yesha was the Director of the Center for Applied Information Technology at the National Institute of Standards and Technology. Dr. Yesha is a senior member of IEEE, and a member of the ACM.This revised version was published online in August 2005 with a corrected cover date.