We study the performance improvement of Location Based Services through the identification and subsequent use of groups of mobile nodes. In our scheme we exploit the formation of nodes into groups in order to reduce the computation load incurred in back-end systems (e.g., Location Servers) and the associated network overhead. The back-end systems track the position and communicate with the Group Leader (GL). The GL, in turn, passes the received information to the members of the group (e.g., through short-range communications). The formation of mobile groups is validated over time to avoid misinterpreted temporary groupings which could endanger the adoption of the reduced load/overhead scheme. A time scheduling scheme based on the Optimal Stopping Theory assists in the finalization of the group validity. Metrics like group compactness are thoroughly assessed in line with the optimal stopping time scheme to increase confidence on group validity and persistence. Performance assessment reveals significant benefits for the considered location based services system.

Future Web business models involve virtual environments where entities interact in order to sell or buy information goods. Such environments are known as Information Markets (IMs). Intelligent agents are used in IMs for representing buyers or information providers (sellers). We focus on the decisions taken by the buyer in the purchase negotiation process with sellers. We propose a reasoning mechanism on the offers (prices of information goods) issued by sellers based on fuzzy logic. The buyer’s knowledge on the negotiation process is modeled through fuzzy sets. We propose a fuzzy inference engine dealing with the decisions that the buyer takes on each stage of the negotiation process. The outcome of the proposed reasoning method indicates whether the buyer should accept or reject the sellers’ offers. Our findings are very promising for the efficiency of automated transactions undertaken by intelligent agents.

Mobile applications are required to operate in highly dynamic pervasive computing environments of dynamic nature and predict the location of mobile users in order to act proactively. We focus on the location prediction and propose a new model/framework. Our model is used for the classification of the spatial trajectories through the adoption of Machine Learning (ML) techniques. Predicting location is treated as a classification problem through supervised learning. We perform the performance assessment of our model through synthetic and real-world data. We monitor the important metrics of prediction accuracy and training sample size.

In certain settings, like for example a Wireless Sensor Network (WSN), contextual information (context) needs to be disseminated between nodes and then interpreted. Dissemination is typically performed through a wireless network infrastructure where resources are scarce. Our focus is on the design/implementation of a context compression scheme that tries to minimize the pieces of information exchanged over the network. Our scheme heavily relies on the multi-value(vectorial) nature of context dissemination messages that flow throughout the network. We adopt the Principal Component Analysis and determine the statistical dependencies between the context vector components. We manage to reduce (compress)the transmitted contextual information down to the identified principal components. A comparative assessment with other energy efficient models is reported indicating the capability of the proposed model to minimize resource consumption.

The requirement for ubiquitous service access in wireless environments presents a great challenge in light of well-known problems like high error rate and frequent disconnections. In order to satisfy this requirement, we propose the integration of two modern service technologies: Web Services and Mobile Agents. This integration allows wireless users to access and invoke semantically enriched Web Services without the need for simultaneous, online presence of the service requestor. Moreover, in order to improve the capabilities of Service registries, we exploit the advantages offered by the Semantic Web framework. Specifically, we use enhanced registries enriched with semantic information that provide semantic matching to service queries and published service descriptions. Finally, we discuss the implementation of the proposed framework and present our performance assessment findings.

Mobile applications are required to operate in ubiquitous environments of dynamic nature. Specifically, the availability of resources and services may vary significantly during a typical session of system operation. As a consequence, mobile applications need to be capable of adapting to these changes to ensure the best possible level of service to the user. Therefore, such adaptive applications may have pre-evaluated the appropriate knowledge of their environment to act efficiently. Such knowledge is not known a priori, so information prediction and proactivity should enhance and extend the functionality of such applications in order to be adaptable to the future changes of their underlying computational environment. In this paper, we discuss and evaluate such a context prediction algorithm.

The PoLoS platform, implemented in the context of the European Union Information Society Technologies (IST) program, focuses on the development, deployment and provision of services and consolidates several technologies (and operation schemes) of the Location Based Services world under a single framework. The demonstration aims to provide an operational overview of the PoLoS platform and highlight the benefits the platform brings in a large-scale, competitive and fast-changing environment.

Article Share on Using proxy cache relocation to accelerate Web browsing in wireless/mobile communications Authors: Stathes Hadjiefthymiades University of Athens, Dept. of Informatics and Telecommunications, Panepistimioupolis, Ilisia, Athens, 15784, Greece University of Athens, Dept. of Informatics and Telecommunications, Panepistimioupolis, Ilisia, Athens, 15784, GreeceView Profile , Lazaros Merakos University of Athens, Dept. of Informatics and Telecommunications, Panepistimioupolis, Ilisia, Athens, 15784, Greece University of Athens, Dept. of Informatics and Telecommunications, Panepistimioupolis, Ilisia, Athens, 15784, GreeceView Profile Authors Info & Claims WWW '01: Proceedings of the 10th international conference on World Wide WebMay 2001Pages 26–35https://doi.org/10.1145/371920.371927Published:01 April 2001Publication History 34citation983DownloadsMetricsTotal Citations34Total Downloads983Last 12 Months4Last 6 weeks0 Get Citation AlertsNew Citation Alert added!This alert has been successfully added and will be sent to:You will be notified whenever a record that you have chosen has been cited.To manage your alert preferences, click on the button below.Manage my AlertsNew Citation Alert!Please log in to your account Publisher SiteGet Access