Network

In this paper, we consider a new method to improve the performance of TCP over wireless networks. The method employs NDG loss-predictor function to determine congestion losses from that of transmission loss. The sender window can adjust its size depending on the loss information. If the loss is due to congestion congestion control algorithm is invoked to decrease the flow rate. If the loss is due to wireless transmission, immediate-recovery algorithm is invoked to recover the losses caused by the sender TCP. To minimise the packet losses due to congestion, we use stability analysis over the system by applying a time-delay control theory. By constructing Hermit matrix, system analysis is made for asymptotic stability. Explicit conditions are derived for Pmax (RED controller) and ? (fNDG parameter) in terms of wireless network parameters. Using the characteristic equation of the Hermite matrix, convergence analysis of the instantaneous queue length at the bottleneck router is made. Convergence of the queue length to a given target value is analysed. This minimise the oscillatory behaviour of the RED router. An approximate solution of queue length is also derived. Our results provide better solutions for global stability and convergence conditions of the wireless system.

Wireless Sensor Networks have been scattered over many unattainable areas such as glaciers, forest, gas, oil water etc to gather real time sensitive information. These Sensor nodes are capable of gathering a large quantity of data by sensing the area, this consumes a large amount of broadcasting and transmission power and thus reducing the life-spam of batteries running sensor node. Through this paper the researcher investigated relationship between the network coding techniques and the transmission power of WSN. Network coding, in belief, is a Layer 3 invention that enhances the network throughput and performance in wireless networks for multicast or broadcast situations. This Paper basically performs the survey on area the where network coding is applied in WSN to enhance the battery life of the nodes by various researchers. It also analyzes the factors which effects the networks lifetime.

The paper evaluates the effectiveness of recent initiatives introduced by the Royal Thai Government proliferate Broadband services in Thailand. With globalization, the society is constantly changing resulting by information technology and Internet access to play an important role in communication, social, political, economic or even environmental. Because of the rapid-technological advancement, it causes that many countries moving up their focus on developing infrastructure to enhance the information technology and innovation. The data transmission not only text messages but also pictures such as VDO conference is important to make use of information technology is faster and more efficient. The perception is very convenient and fast and hence requires a good core broadband infrastructure. The role of Information and Communication Technology infrastructure (ICT infrastructure) enables leaders on governments’ decision based on the real time and reliable information. Of course, the government leaders in many countries realized that the quality and performance on ICT infrastructure would directly affect developing countries. In order to monitor the countries in the crisis situation, the stable and qualified network is required which the government called as S-M-A-R-T network. Under ICT2020 Policy Framework and Broadband Policy, Ministry of ICT accelerates connected S-M-A-R-T network to develop ICT infrastructure in Thailand recently. On another hand, Thailand economy is also important mechanism for strengthening competitiveness. The new business opportunities with many other countries have defined a policy and planning in developing Broadband seriously and continuously. In this paper, the study will identify the policies and plans of development and building broadband infrastructure of the leaders in the development of broadband top of the world, including Japan, South Korea, Singapore, The United States, Australia and Sweden, a country that have a clear policy and plan development. The projects initiated and measures taken by the Government of Thailand in the broadband sector have been studied. The information has been gathered by interacting with the executive officers of the National Broadcasting and Telecommunications Commission (NBTC), Ministry of Information Communication and Technology, Thailand, from interviewing the officers of government departments: Ministry of Education (MOE), Ministry of Public Health (MOH) and etc.

In this paper, the application of the Taguchi method with fuzzy logic for optimizing the electrical discharge machining process with multiple performance characteristics has been reported. A multi-response performance index is used to solve the EDM process with multiple performance characteristics. The machining parameters (discharge current (IP), pulse on time (Ton), pulse off time (Toff) and down time) are optimized with considerations of the multiple performance characteristics (electrode wear rate and material removal rate). Experimental results are presented to demonstrate the effectiveness of this approach.

The unsteady state mass conservation equation for chlorine concentration decay in drinking water in a pipe line network for axisymmetric flow is solved analytically with the help of Hankel transform. The numerical values and graphical representations are shown by using MATLAB for various values of chlorine consumption rate, diffusivity, time and fluid velocity etc.

Vehicular ad hoc networks (VANETs) enable vehicles to communicate with each other (V2V) as well as roadside infrastructure units (V2I) without any fixed infrastructure. These roadside units provide different services such as driver information systems and Internet access. VANETS can be used to improve the comfort applications such as traffic information, weather information, gas station/restaurant location information or interactive communication such as Internet access and downloads. The high speed and high mobility of vehicles cause many challenges to establishing and maintaining connection of these roadside units. In this paper we introduce Fuzzy Logic Based Stable Routing in VANET. The essential purpose of new algorithm is to predict the future behaviour of vehicles by the use of the characteristics of vehicle movements such as speed average, speed of drivers and standard deviation; and also to calculate stablitiy of routes with the help of fuzzy logic for selecting routes with the most stability and least length. The proposed algorithm is simulated by considering mobility model, generated by the VanetMobiSim tool. The simulation results show that the proposed approach with increasing the number of nodes, will increase the Average Route Stability Indicator Minimum and decrease Average Route Length Minimum. This issue cause to provide an accurate and efficient method of estimating and evaluating the route stability in dynamic VANETs.

A Mobile Ad hoc Network is a collection of mobile wireless nodes that combine to form a network without any infrastructure. The main challenges in MANET are reliability, bandwidth and battery power. Broadcasting is important in MANET for routing information discovery. Broadcasting is the process in which a source node sends a message to all other nodes in MANET. The broadcast operation as a fundamental service in mobile ad hoc networks is prone to the broadcast storm problem if forwarding nodes are not carefully designated. This paper proposes a simple broadcast algorithm called double-covered broadcast which takes advantage of broadcast redundancy to improve the delivery ratio in an environment that has rather high transmission error rate. Only a set of selected nodes will forward the broadcast message. The selected nodes called forwarding nodes must satisfy the following two requirements: 1) the sender’s 2-hop neighbors are covered and 2) the sender’s 1-hop neighbors are either forwarding nodes or non forwarding nodes covered by at least two forwarding neighbors. The retransmissions of the forwarding nodes are received by the sender as the confirmation of their reception of the packet. The non forwarding neighbors do not acknowledge the reception of the broadcast. The proposed algorithm has many metrics such as balancing the average retransmission redundancy, avoid broadcast storm problem, recovering the transmission error locally and increasing the broadcast delivery ratio in a high transmission error rate environment.

Wireless Sensor Networks are used in numerous security sensitive applications, it composed of a huge number of resource limited sensors therefore we should make sure the network is secured against security attacks. Denial of service attack in WSNs is a serious attack that reduces the network capacity dramatically and the users fail to receive expected service. Many schemes have been proposed to tolerate or destroy DoS attack, but very few can identify intruders and provide security against this attack. In this paper, we explore the effects of DoS in WSN, effective security methods for achieving the security against this attack. Finally two important types of DoS attacks called jamming and reply attack are studied and possible solutions are recommended.

Since the introduction of Automated Teller Machines (ATMs) in Nigeria, cash handling has really reduced especially for those who live in the city and have easy access to ATM machines by means of their ATM cards. People no longer see the needs to carry excess cash at home when they already have an ATM card since ATM machines can be easily accessible. ATM operation did not turn out to be all rosy as it started out. This research surveys ATM malfunctions in four states in Nigeria to ascertain the nature of malfunction that is prevalent and formulates a modification algorithm/routine that should possibly correct this ATM misfit.

This paper proposes a distributed Quality of Service (QoS) oriented routing algorithm for hybrid wireless network. The wireless applications are demanding robust networks with end to end QoS requirements. Hybrid wireless networks will be the best next generation network. So providing QoS routing algorithm for such networks is on demand research. Here the QoS-Oriented Distributed routing protocol (QOD) is proposed to enhance the QoS support of hybrid wireless networks. This protocol consists of 6 algorithms. 1. Neighbor selection algorithm 2. Malicious Node Detection 3.Packet scheduling 4. Node mobility speed based packet assigning, 5. Packet data compression deflate algorithm 6.Tra?c redundancy elimination algorithm. The simulation results show that packet delay, packet loss is getting improved.