Browsing by Subject "service discovery"
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Item Agents2Go: An Infrastructure for Location-Dependent Service Discovery in the Mobile Electronic Commerce Environment(ACM, 2001-07-14) Ratsimor, Olga Vladi; Korolev, Vladimir; Joshi, Anupam; Finin, TimIn recent years, the growth of Electronic Commerce and Mobile Computing has created a new concept of Mobile Electronic Commerce. In this paper we describe the Agents2Go System that attempts to solve problems related to location dependence that arise in a Mobile Electronic Commerce environment. Agents2Go is a distributed system that provides mobile users with the ability to obtain location dependent services and information. Our system also automatically obtains a user’s current geographical location in CDPD (Cellular Digital Packet Data) based systems without relying on external aids such as GPS (Global Positioning System).Item Dynamic Service Discovery for Mobile Computing: Intelligent Agents Meet Jini in the Aether(Kluwer Academic Publishers, 2001-02-28) Chen, Harry; Joshi, Anupam; Finin, TimothyThe emergence of ad-hoc pervasive connectivity for devices based on Bluetooth-like systems provides a new way to create applications for mobile systems. We seek to realize ubiquitous computing systems based on the cooperation of autonomous, dynamic and adaptive components (hardware as well as software) which are located in vicinity of one another. In this paper we present this vision. We also describe a prototype system we have developed that implements parts of this vision { in particular a system that combines agent oriented and service oriented approaches and provides dynamic service discovery. We point out why existing systems such as Jini are not suited for this task, and how our system improves on them.Item GSD: A Novel Group-based Service Discovery Protocol for MANETs(IEEE, 2002-09-09) Chakraborty, Dipanjan; Joshi, Anupam; Yesha, Yelena; Finin, TimThis paper proposes a novel distributed service discovery protocol for Mobile Ad hoc Networks. The protocol is based on the concept of peer-to-peer caching of service advertisements and group-based intelligent forwarding of service requests. It does not require a service to register to a registry or lookup server. Services are described using an ontology based on the DARPA Agent Markup Language (DAML+OIL). We exploit the semantic class/subClass hierarchy of DAML to describe service groups and use this semantic information to selectively forward service requests to respective nodes. DAML-based service description helps us in achieving increased flexibility in service matching. We also present simulation results of our protocol and show that our protocol achieves increased efficiency in discovering services by efficiently utilizing bandwidth by controlling forwarding of service requests.Item Integrating Service Discovery with Routing and Session Management for Ad hoc Networks(Elsevier B.V., 2004-03-31) Chakraborty, Dipanjan; Joshi, Anupam; Yesha, YelenaIn this paper, we propose GSR: a new routing and session management protocol for ad-hoc networks as an integral part of a service discovery infrastructure. Traditional approaches place routing at a layer below service discovery. While this distinction is appropriate for wired networked services, we argue that in ad-hoc networks this layering is not as meaningful and show that integrating routing with discovery infrastructure increases system efficiency. Central to our protocol is the idea of reusing the path created by the combination of a service discovery request and a service advertisement for data transmission. This precludes the need to use separate routing and discovery protocols. GSR also combines transport layer features and provides end-to-end session management that detects disconnections, link and node failures and enables service-centric session redirection to handle failures. This enables GSR to accommodate service-centric routing apart from the traditional node-centric routing. We compare GSR with AODV in terms of packet delivery ratio, response time and average number of hops traveled by service requests as well as data. GSR achieves better packet delivery ratio with a minor increase of the average packet delivery delay.Item A Queueing Theoretic Model for Service Discovery in Ad-hoc Networks(2004-01-31) Chakraborty, Dipanjan; Shenoi, Avinash; Yesha, Yelena; Yesha, Yaacov; Joshi, Anupam; Singhal, MukeshThis paper describes an analytical model for service discovery protocols in ad-hoc networks. We propose a bottom-up approach towards modeling various essential features of distributed service discovery protocols. More specifically this paper proposes a method to analytically model the service cache (SC) on an ad-hoc node. %A Service Cache stores service advertisements. We employ the use of stochastic process models and fundamental queuing theory to model the data present in the cache. We show using simulations how our model can be used to predict the service cache usage at the node level. Our model is based on the assumption of non-preemption of service descriptions from the service cache and that the system is at steady state. We assume that there are infinite number of services in the system. We also experimentally verify that our model predicts the service system behavior reasonably well even when the assumption of infinite services does not hold.Item A Secure Infrastructure for Service Discovery and Access in Pervasive Computing(ACM, 2003-10-12) Undercoffer, Jeffrey; Perich, Filip; Cedilnik, Andrej; Kagal, Lalana; Joshi, AnupamSecurity is paramount to the success of pervasive computing environments. The system presented in this paper provides a communications and security infrastructure that goes far in advancing the goal of anywhere - anytime computing. Our work securely enables clients to access and utilize services in heterogeneous networks. We provide a service registration and discovery mechanism implemented through a hierarchy of service management. The system is built upon a simplified Public Key Infrastructure that provides for authentication, non-repudiation, anti-playback, and access control. Smartcards are used as secure containers for digital certi cates. The system is implemented in Java and we use Extensible Markup Language as the sole medium for communications and data exchange. Currently, we are solely dependent on a base set of access rights for our distributed trust model however, we are expanding the model to include the delegation of rights based upon a predefined policy. In our proposed expansion, instead of exclusively relying on predefined access rights, we have developed a flexible representation of trust information, in Prolog, that can model permissions, obligations, entitlements, and prohibitions. In this paper, we present the implementation of our system and describe the modifications to the design that are required to further enhance distributed trust. Our implementation is applicable to any distributed service infrastructure, whether the infrastructure is wired, mobile, or ad-hoc.Item Service Composition for Mobile Environments(Kluwer Academic Publishers, 2005-01-01) Chakraborty, Dipanjan; Joshi, Anupam; Finin, Tim; Yesha, YelenaService 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.Item Service Discovery in the Future Electronic Market(AAAI, 2000) Chen, Harry; Chakraborty, Dipanjan; Xu, Liang; Joshi, Anupam; Finin, TimThe trend that the electronic market is taking, aided by the concomitant development of mobile devices, suggests a major change from the way electronic commerce is done today. The increased use of PDAs and laptops requires that ecommerces ervices and transaction processing facilities need to be accessed from a wireless device. This brings new and challenging research problems into the picture. Discovering services dynamically will become increasingly important in the mobile e-commerce scenario. A service will be selected automatically for a job, taking into consideration its physical location, "context" and other semantic information. To support this scenario, the existing discovery mechanismsn eed to moveb eyond trivial attribute or interface matching. They would need to be much more knowledge based. In this paper, we present a summaryo f the existing service discovery protocols and the work that we have done in the service discovery area in our quest to make service discovery more dynamic.