Peer-to-peer (P2P) overlay is a distributed application architecture in which peers share their resources. Peers are equally privileged, equipotent participants in the application. Several algorithms for enhancing P2P file searching have been proposed in the literature. In this paper, we have proposed a unique approach of reducing the P2P search complexity and improving search efficiency by using distributed algorithms. In our approach a peer mounts other popular peer's files and also replicates other popular files or critical files identified using a threshold value. Once a file is mounted, file access requests can be serviced by transparently retrieving the file and sending it to the requesting peer. Replication used in this work improves the file retrieval time by allowing parallel transfer. We have shown the performance analysis of our proposed approach which shows improvement in the search efficiency.

Next generation vehicular communication environment will consist of heterogeneous radio access networks (RAN). For seamless connectivity, vertical handover is a mandatory requirement. A novel context aware vertical handover algorithm is presented here. TOPSIS (Technique for Order Preference by Similarity to Ideal Solution), which is a multi criteria decision making (MCDM) tool, is used for the development of algorithm and MATLAB/SIMULINK is used as simulation platform. The optimum network is selected, based on multiple factors such as network traffic load, velocity of mobile station, data rate, usage cost and initial delay of network, among the available networks such as WiMax, WLAN and UMTS. This algorithm has been tested by simulating a virtual road traffic scenario. Variations in optimum RAN selection with vehicle speed keeping network traffic load constant and RAN selection with network traffic load keeping vehicle speed constant are shown graphically. The proposed algorithm is very simple yet powerful compared to the existing VHO algorithms and hence requires less execution time.

Free-Space Optics (FSO) is a wireless optical technology that enables optical transmission of data, voice and video communications through the air, up to 10 Gbps of data, based on the use of the free space (the atmosphere) as transmission medium and low power lasers as light sources.
Quality and performance of FSO links are generally affected by link distance and weather conditions like environmental temperature and light, sun, fog, snow, smoke, haze and rain. In this paper we study the effects of weather conditions on the performance of FSO links, taking the climate of Algeria as an example, and since there is no known analysis on the effects of weather conditions in this country, this paper offers an attempt to analyze and identify the challenges related to the deployment of FSO links under Algeria's weather. We also present a Graphic User Interface "GUI" to provide an approximate availability estimate of an atmospheric optical link in term of probability of connection.

This Paper discusses the digital forensic tool that uses a field Programmable Gate Array [FPGA] based software for deep packet inspection in network Router for a Bit Torrent Handshake message. Extracts the "Information Hashing" of the file being shared, compares the hash against a list of known contraband files for forensic analysis and it matches the message to a log file. Forensic analysis gives several optimization techniques for reducing the CPU time required for reducing the CPU time required to process packets are investigated along with their ability to improve packet capture performance. Experiments demonstrate that the system is able to successfully capture and process Bit Torrent Handshake message with a probability of at least 99.0% under a network traffic load of 89.6 Mbps on a 100 Mbps network.

In order to ensure and enforce endpoint security, Network Access Control (NAC) is attracting considerable interest from the research community. Most NAC architectures are based on 802.1x, EAP (Extensible Authentication Protocol), EAPoL (EAP over LAN) 802.11i, 802.11w, and RADIUS (Remote Authentication Dial-In User Service) protocols. Unprotected management and control frames in some of above protocols lead to several attacks. Eliminating flaws completely in design of each protocol is a challenge. These flaws help malicious user and infected endpoint to intrude into the NAC architecture to make damage into it. Many researches have been carried out to address this issue. In this paper, we have made an attempt to explain attacks in above protocols and present a survey and analysis of different solution approaches proposed by researchers. The affect of vulnerability and attack of above protocols in NAC is also discussed. The finding of this review will provide useful insights into the vulnerabilities, attacks in above protocols, and their proposed solutions with issues, which may create a research scope for strengthening security in NAC.

Edge detection of images is one of the basic and most significant operations in image processing and is used for object background separation, 3-D interpretation of a 2-D image, and pre-processing in image understanding and recognition algorithms. In this paper we investigate cellular automata linear rules for edge detection and based on this investigation we have classified the rules into no edge detection rules, strong edge detection rules and weak edge detection rules. Finally, we show the comparative analysis of the proposed technique with already defined techniques for edge detection and the results show desirable performance.

In current scenario, there are always impending threats from militants and terrorists within and out of a country. The sensor networks play a vital role in minimizing the loss of human lives in the event of usual calamity and artificial sabotage created by terrorists. The sensor networks can be successfully deployed in any difficult geographical terrains where manual round-the-clock surveillance is highly impossible. Energy aware routing is immensely helpful to sensor networks in the aspect of extending the life span of the WSNs. In this paper, an automatic suspected terror system based on wireless sensor networks is developed, which is designed for high-rise metro structure. In order to provide early extinguish of impending threats by putting any bomb, large numbers of detectors which periodically measure noise, smell, infringement, vibration, temperature concentration, unidentified stranger photo are deployed from major streets. Those scattered detectors report their monitoring information to the surveillance center via the self-organizing hierarchical intelligent wireless sensor networks (IWSN). Test results from it show that the automatic suspected terror system achieves the design requirements.

The need for scalable systems in market demands in terms of lower computing costs and protection of customer investment in computing: scaling up the system to quickly meet business growth is obviously a better way of protecting investment: hardware, software, and human resources. A scalable system should be incrementally expanded, delivering linear incremental performance with a near linear cost increase, and with minimal system redesign (size scalability), additionally, it should be able to use successive, faster processors with minimal additional costs and redesign (generation scalability). On the architecture side, the key design element is the interconnection network. The interconnection network must be able to increase in size using few building blocks and with minimum redesign, deliver a bandwidth that grows linearly with the increase in system size, maintain a low or (constant) latency, incur linear cost increase, and readily support the use of new faster processors. The major problem is the ever-increasing speed of the processors themselves and the growing performance gap between processor technology and interconnect technology. Increased central processing unit (CPU) speeds and effectiveness of memory latency-tolerating techniques.