Publications
Abstract: Pervasive computing represents a wide variety of information processing disciplines which are free from spatial and temporal constraints. One of its aspects is wireless data dissemination which is the topic of this paper. Wireless data dissemination is an economical and efficient way to make desired data pervasively available to a large number of nomadic or static users. One of the foremost challenges in this area is to make topical information available anywhere and anytime. Effectiveness of data dissemination depends to a large extent on access latency and there has been some significant work on data caching using broadcast to minimize latency. A serious concern in this regard is the uncertainty between user access latency and ubiquitous availability of topical data. The more the user access time, the less precisely is the topical information available. Our research shows that the user access latency can be significantly reduced by the use of data staging and by data caching at different levels. In this paper we propose an innovative public data dissemination strategy which is based on a new architecture. In our approach we use a hybrid (push and pull based) approach where data is adaptively scheduled to utilize limited bandwidth. We show that the use of data staging helps mobile users to access and stage his data anywhere and at anytime. We claim that our approach manages topical data and other frequently accessed data with low latency and is energy efficient. We justify our claim through performance evaluation.
Abstract: Recently there have been significant improvements in various aspects of mobile discipline. Powerful mobile devices are becoming more common and location tracking techniques have been improved to find the location of a mobile user with precision. The widespread use of internet, electronic shopping, mobile and wireless communication systems, etc., motivated researchers and developers to migrate all types of information and also services to the web. We, therefore, envision an all powerful web system where service provisioning is also included as one of its capabilities. The migration of web services to internet provided an excellent way to achieve application-to-application interaction which made it possible for companies to manage their business activities efficiently, economically, and with a high degree of automation. At the same time it created a continuously available pervasive market where they can enjoy their shopping, can prepare their travel planning, complete their day to day activities, and any other special activity with utmost flexibility. We call this pervasive market "Web Bazaar" which can be view as a virtual environment around us where we can find everything (items and services) close to our finger tips.
Abstract: Wireless Data dissemination is an effective way to disseminate large amount of data to a large mobile user population. Our project, called “DAYS (DAta in Your Space)”, investigates information management issues in wireless space. One of the main objectives of DAYS is to build a system to provide transactional and web services facilities globally. This paper discusses the creation of a location domain and proposes an algorithm for creating location dependent data. A new indexing scheme for accessing Location Dependent Data (LDD) in DAYS has also been presented which not only provides a bound on the access time but also allows significant energy conservation in mobile devices.
4. Debopam Acharya & Vijay Kumar ; Location based Indexing Scheme for DAYS, Proceedings of the 4th ACM International Workshop on Data engineering for Wireless and Mobile access (MobiDe) 2005,Baltimore, MD, USA June 12 - 12, 2005
Abstract: Data dissemination through wireless channels for broadcasting information to consumers is becoming quite common. Many dissemination schemes have been proposed but most of them push data to wireless channels for general consumption. Push based broadcast is essentially asymmetric, i.e., the volume of data being higher from the server to the users than from the users back to the server. Push based scheme requires some indexing which indicates when the data will be broadcast and its position in the broadcast. Access latency and tuning time are the two main parameters which may be used to evaluate an indexing scheme. Two of the important indexing schemes proposed earlier were tree based and the exponential indexing schemes. None of these schemes were able to address the requirements of location dependent data (LDD) which is highly desirable feature of data dissemination. In this paper, we discuss the broadcast of LDD in our project DAta in Your Space (DAYS), and propose a scheme for indexing LDD. We argue that this scheme, when applied to LDD, significantly improves performance in terms of tuning time over the above mentioned schemes. We prove our argument with the help of simulation results.
5. Debopam Acharya & Vijay Kumar ; Web Bazaar: A Location-Dependent Secured Mobile Web Service System , ISI Journal for Mobility in Information systems and Databases, August, 2005
Abstract: Web Services has evolved to be a promising technology for developing application in open, loosely coupled and distributed computing environments and in mobile commerce. The web is no longer a repository of information and has evolved into a medium for providing general and user-specific services to customers. One of the key requirements of the web services to meet user expectation is its secure universal accessibility free from temporal and spatial constraints. To access the web services from anywhere and anytime in a secured manner, a suitable Mobile Web Services architecture is needed which must overcome the limitations of the mobile environment (service discovery, low bandwidth, insecurity, limited power source and scalability bottleneck). This paper exploits the advances in wireless broadcast discipline and proposes a new architecture that overcomes a number of problems in discovering and using web services. At the same time it also proposes a new location based signature scheme to add an extra dimension to the authentication of the mobile transactions.
6. Debopam Acharya & Vijay Kumar ; DAYS: A Data Staging and Push-Pull based Location Dependent Wireless Data Dissemination System,Sent for publication, 22nd International Conference on Data Engineering (ICDE, 2006) April 3-7, Atlanta, GA, 2006
Abstract: Wireless data dissemination is an economical and efficient way to make desired data available to a large number of nomadic or static users. Effectiveness of such data dissemination depends to a large extent on minimizing tuning time and access latency. Earlier works show data caching using broadcast does significantly reduce these parameter values. We demonstrate through our research that user access latency can be significantly reduced by combining data staging and data caching at different levels. In this paper we report our ongoing research in the project DAta in your Space (DAYS) where we integrate pull and push based data access. To achieve this, we extend our location based indexing scheme used for push based wireless data to include index for on demand data which is being broadcasted along with the other pushed data. We show that this hybrid system of disseminating location dependent data (LDD) is comparatively more efficient than a pure push or pull based wireless data dissemination system.
7. Debopam Acharya & Vijay Kumar ; On-demand Broadcast issues in Data Dissemination Systems for 4G Wireless Networks (Continuing Work)