In the next generation of heterogeneous wireless networks (HWNs), a large number of different radio access technologies (RATs) will be integrated into a common network. In this type of networks, selecting the most optimal and promising access network (AN) is an important consideration for overall networks stability, resource utilization, user satisfaction, and quality of service (QoS) provisioning. This paper proposes a general scheme to solve the access network selection (ANS) problem in the HWN. The proposed scheme has been used to present and design a general multicriteria software assistant (SA) that can consider the user, operator, and/or the QoS view points. Combined fuzzy logic (FL) and genetic algorithms (GAs) have been used to give the proposed scheme the required scalability, flexibility, and simplicity. The simulation results show that the proposed scheme and SA have better and more robust performance over the random-based selection.

Abstract-Image retrieval is still an active research topic in the computer vision field. There are existing several techniques to retrieve visual data from large databases. Bag-of-Visual Word (BoVW) is a visual feature descriptor that can be used successfully in Content-based Image Retrieval (CBIR) applications. In this paper, we present an image retrieval system that uses local feature descriptors and BoVW model to retrieve efficiently and accurately similar images from standard databases. The proposed system uses SIFT and SURF techniques as local descriptors to produce image signatures that are invariant to rotation and scale. As well as, it uses K-Means as a clustering algorithm to build visual vocabulary for the features descriptors that obtained of local descriptors techniques. To efficiently retrieve much more images relevant to the query, SVM algorithm is used. The performance of the proposed system is evaluated by calculating both precision and recall. The experimental results reveal that this system performs well on two different standard datasets.

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The security in cognitive radio networks (CRNs) has been attracting continuously growing attention, due to the open and dynamic nature of cognitive radio architecture. In this

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In heterogeneous networks environment, Vertical Handover Decision (VHD) algorithms help mobile terminals to choose the best network between all the available networks. VHD algorithms provide the QoS to a wide range of applications anywhere at any time. In this paper, a generic and novel solution to solve the Vertical Handover (VHO) problem has been developed. This solution contains two major subsystems: The first subsystem is called elimination system. Elimination system is received the different VHO criteria such as received signal strength, network load balancing and mobile station speed from the different available networks. After that, the inappropriate alternatives are eliminated based on the elimination conditions. The second subsystem is a Multiple Criteria Decision Making (MCDM) system that chooses the appropriate alternative from the remaining alternatives of the elimination phase. For simulate the proposed solution, MATLAB program is used with aid of MATLAB-based toolbox that is called RUdimentary Network Emulator (RUNE). The combination of both subsystems avoids the processing delay caused by unnecessary computation over available networks which do not ensure connection performance. Also it avoids increasing the number of unnecessary handovers, ping pong effect, blocking rate and dropping rate by reducing the handover failure rate. A performance analysis is done and results are compared to other reference algorithms. These results demonstrate a significant improvement over other reference algorithms in terms of handover failure rate, percentage of satisfied users, and percentage of the low cost network usage. systems and Bluetooth, in addition to the traditional cellular networks which are nearly universally accessible today. For a satisfactory user experience, MTs must be able to seamlessly transfer to the best Radio Access Technologies (RATs) between all available candidates with no perceivable interruption to an ongoing conversation, which could be a voice or video session. Such ability to Hand-Over (HO) among Heterogeneous Wireless Networks (HWNs) is referred to as Vertical Handover (VHO). VHO algorithms are one significant challenge for Radio Resource Management (RRM) in HWN. The VHO is one of the key components that must be addressed and considered carefully in the HWN environments and need to be designed to provide the required Quality of Service (QoS) to a wide range of applicationsThe performance of the VHD algorithms still need to be improved through using new tools and methods to make the handover decision, as well as taking into account the different viewpoints when choosing the criteria of the handover decision. As some of the existing VHD algorithms, do not exploit the advantages of the multi-criteria nature of the VHD that can give better performance than single criterion algorithms due to the flexible and complementary nature of the different criteriaFurthermore, considering only one or two criteria in the VHD solution is not sufficient to provide a good solution and usually leads to un...

The future Heterogeneous Wireless Network (HWN) is composed of multiple Radio Access Technologies (RATs) and domains, therefore, new Radio Resource Management (RRM) schemes and mechanisms are necessary to benefit from the individual characteristics of each RAT and to exploit the gain resulting from jointly considering the whole set of the available radio resources in each RAT. Vertical Handover (VHO) enables users to access several networks such as WLAN, WMAN, WPAN, and WWAN in parallel. It allows the applications even the real time application to be seamlessly transferred among different networks. In this paper, a decision support system is developed to address the VHO problem. This system combines fuzzy logic and ELECTRE, a MCDM algorithm, to the problem of VHO. This combination decreases the influence of the dissimilar, imprecise, and contradictory measurements for the VHO criteria coming from different sources. A performance analysis is done and the results are compared with traditional algorithms for VHO. These results demonstrate a significant improvement with our developed algorithm.