A utility-based fuzzy TOPSIS method for energy efficient network selection in heterogeneous wireless networks

Mobile terminals in 4G heterogeneous wireless networks continuously undergo horizontal and vertical handovers. In order for a mobile terminal to be connected to a network in the best possible way in terms of QoS performance and energy consumption, access network selection as the main decision within the handover process is obviously crucial. This paper presents a novel method that takes into account user preferences, network conditions, QoS and energy consumption requirements in order to select the optimal network which achieves the best balance between performance and energy consumption. The proposed network selection method incorporates the use of parameterized utility functions in order to model diverse QoS elasticities of different applications, and adopts different energy consumption metrics for real-time and non-real-time applications. User preferences are easily configured for different application and situation contexts through the use of linguistic assessments and their representation as triangular fuzzy numbers. The aggregation of multiple criteria for the calculation of the overall rating of the networks is performed through the use of the Fuzzy Set Representation TOPSIS method that resolves the issue of inconsistency related to conflicting decision criteria and is modified through the use of the employed utility functions for the elimination of the ranking abnormality problem. Finally, simulations are conducted in order to demonstrate how the proposed method would work and confirm its suitability and effectiveness. © 2011 Elsevier B.V. All rights reserved

A utility-based fuzzy TOPSIS method for energy efficient network selection in heterogeneous wireless networks

Mobile terminals in 4G heterogeneous wireless networks continuously undergo horizontal and vertical handovers. In order for a mobile terminal to be connected to a network in the best possible way in terms of QoS performance and energy consumption, access network selection as the main decision within the handover process is obviously crucial. This paper presents a novel method that takes into account user preferences, network conditions, QoS and energy consumption requirements in order to select the optimal network which achieves the best balance between performance and energy consumption. The proposed network selection method incorporates the use of parameterized utility functions in order to model diverse QoS elasticities of different applications, and adopts different energy consumption metrics for real-time and non-real-time applications. User preferences are easily configured for different application and situation contexts through the use of linguistic assessments and their representation as triangular fuzzy numbers. The aggregation of multiple criteria for the calculation of the overall rating of the networks is performed through the use of the Fuzzy Set Representation TOPSIS method that resolves the issue of inconsistency related to conflicting decision criteria and is modified through the use of the employed utility functions for the elimination of the ranking abnormality problem. Finally, simulations are conducted in order to demonstrate how the proposed method would work and confirm its suitability and effectiveness. © 2011 Elsevier B.V

Network selection in a virtual network operator environment

Service offerings of virtual network operators should focus on the needs of distinct groups of users in order to face challenges posed in the saturated telecommunications mass market. Since a virtual operator may hire capacity from a number of host networks with varied characteristics, the selection of an optimal host network according to network attributes, user preferences and QoS requirements results to the provision of services with desirable characteristics adding value for the user. Network selection in such an environment has not been studied as all previous works have focused exclusively on handover decisions in heterogeneous wireless networks. This article describes a network selection method in a virtual operator environment that uses a modified version of TOPSIS to rank alternative networks. The proposed modification enables the inclusion of QoS requirements in the ranking results. The uncertainty of user preferences is handled through the use of linguistic assessments and triangular fuzzy numbers. Simulations conducted show that the proposed approach is effective in deciding the optimum network according to all decision factors. © 2012 IFIP International Federation for Information Processing

Integrating heterogeneous communication and messaging systems in an object-oriented middleware framework

Integrated communications have been largely associated with message-oriented middleware in collaborative distributed computing environments, both on small and large scales. Past experience has shown that monolithic architectures based on large executables are extremely difficult to maintain and very unresponsive to change. This paper aims at proposing an intelligent, object-oriented communications and messaging architecture based on interrelated business objects and components, designed to support business-to-business communication. The philosophy behind our approach has been to construct a scalable and flexible system architecture that enables the incorporation of new services at minimum effort. The framework allows for the implementation of reusable components, independently from the core architecture, that can be automatically discovered, configured and plugged-in to the system and used as.cartridges. on demand, according to the communication requirements of the application that will make use of the bearers linked to the system. © Springer-Verlag Berlin Heidelberg 200

Depth-assisted edge detection via layered scale-based smoothing

This paper deals with the subject of using depth data to aid the process of edge detection. Edge detection and stereo vision have had along and abiding relationship, with several implementations of correspondence algorithms depending on edge detection techniques for robustness. The inverse however, has rarely been addressed. What if human vision, which our discipline is attempting to model and recreate, utilizes stereoscopy (and hence, depth information) in order to aid the process of edge discovery, rather than the other way around? Our goal in this paper is to investigate this hypothesis and to establish whether the use of depth data can improve the performance of existing edge detection techniques. More specifically, we show how we used image distance estimates in order to improve the performance of the ubiquitous Gaussian smoothing filter in its role as a pre processor for various edge-detection operators, such as the one developed by Canny. Our approach ensures that the Gaussian smoothing filter is applied in such a way as to eliminate as much noise as possible, while preserving adequate detail in all parts of the image. This is accomplished by the ‘layering’ of the image into multiple separate sub-images and their subsequent independent smoothing. The layering process is guided by depth data, which is presumed to have been derived through stereoscopy or other means. The images are then re-composited and analyzed for edge information by an implementation of the Canny edge detector. Results are presented both with and without the application of our extended smoothing preprocessor for comparison

Electronic transformation of local government: An exploratory study

The paper examines the critical success factors for employees' adoption of the unified Local Government Access Framework (LGAF), deployed for the Central Union of Municipalities and Communities of Greece. Following an extensive bibliographical survey, an initial conceptual framework (CF1) based on the Technology Acceptance Model (TAM) for LGAF adoption is proposed, which is empirically explored within sixteen Local Governments Organizations. The CF1 is revised using the structured-case approach. New concepts discovered during each research cycle revealed that LGAF adoption is a procedure of experiential judgement. The applicability of the TAM is investigated and the model is enhanced, exploring additional variables that affect perceived ease of use, perceived usefulness and actual use. A final complementary CF2 is presented and the evaluation of this model according to the data received from the case studies is discussed. Copyright © 2011, IGI Global