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Change-point detection schemes are a promising approach for detecting network anomalies, such as attacks and epidemics by unknown viruses and worms. They detect those events as change-points. However, they generally also detect false-positive change-points, those caused by other events such as hardware trouble. A scheme is needed that only detects true- positive change-points, caused by attacks and...
In this paper, one improved frame error rate (FER) estimation approach in high Signal Noise Ratio (SNR) region for low-density parity-check (LDPC) codes is reported. Firstly dominant trapping sets (TSs), accounting for most of FER in high SNR region, are picked out as decoding result, with input of decoder consisting of a group of biased bits. And how those biased bits are chosen is reduced to finding...
The accuracy of localization is a significant criterion to evaluate the practical utility of localization algorithm in wireless sensor networks. In mostly localization algorithms, one of the main methods to improve localization accuracy is to increase the number of anchor nodes. But the number of anchor nodes is always limited because of the hardware restrict, such as cost, energy consumption and...
Structured overlays provide a basic substrate for many peer-to-peer systems. Existing structured overlays can be classified into two categories, O(logN)-hop ones and O(l)-hop ones. The former are suitable for large and dynamic systems, while the latter are suitable for small or stable ones. However, for the lack of adaptivity, it is difficult for a peer-to-peer system designer to choose from these...
Topology control (TC) aims at tuning the topology of highly dynamic networks to provide better control over network resources and to increase the efficiency of communication. Recently, many TC protocols have been proposed. The protocols are designed for preserving connectivity, minimizing energy consumption, maximizing the overall network coverage or network capacity. Each TC protocol makes different...
Peer-to-peer and mobile ad hoc networks have established a strong connection due to the fact that peer-to-peer models present effective solutions for decentralized systems. Pure and hybrid peer-to-peer networks have propagated as design models for such decentralized systems. Super-peer networks, in which some nodes (super peers) are selected and assigned special roles, have been proposed as a compromise...
In recent time, new advanced wireless systems emerged at the world markets. One of the most promising is undoubtedly IEEE 802.16 standard, also known as WiMAX. For both, service providers and potential customers, is necessary to know its basic capabilities, such as the number of supported subscriber per BS or transferred data rate that may be delivered. This paper is aimed at 802.16-2004 standard...
Lack of infrastructure, central controlling authority and the properties of wireless links make mobile ad hoc networks (MANETs) vulnerable to attacks. Several protocols have been proposed to make the routing protocols handle attacks in MANETs. These protocols detect the misbehaving nodes and re-route the data packets around them, mostly along the shortest such path. However, no single protocol handles...
According to the actual landform of underground coal mine and the demand of security monitoring, in this paper a coal mine wireless and integrated security monitoring system which combine wireless sensor network and wire monitoring network is proposed. This paper emphasizes a wireless sensor network for coal mine monitoring. In the light of the actual circumstances of coal mine, we propose two-leveled...
The convergence of future fixed and wireless networking more and more requires solutions for transporting realtime application data to IP enabled mobile devices and mobile networks. Even if the general Mobile IPv6 protocol performs sufficient in macro environments with non-realtime requirements, seamless mobility demands some more enhanced protocol procedures in between the mobile client and the involved...
System and network security are significant challenges facing the Internet community today. Hi-tech crime is on the increase and is a threat to a budding online business environment. Reconnaissance technologies that enable the security community to keep abreast of new threats have been developed and deployed. These technologies monitor illegitimate Internet traffic but appropriate data analysis is...
The recent explosion in bandwidth available to home users has caused traffic rates for commercial national networks to increasing rapidly. This presents a problem for any core network monitoring tool as the traffic rate it is expected to monitor is rising on a monthly basis. Security within these networks is paramount as they are now a stable home of trade and commerce. This paper suggests that the...
This paper presents a proxy-based visual content repurposing approach, which is used to repurpose visual content dynamically for the transmission over heterogeneous networks and end devices. We use a series of repurposing proxies in a chain fashion between the server and multiple client devices. In order to find the appropriate chain of repurposing services that maximizes the user's satisfaction with...
We have made detailed measurements, on the impact of modern Wireless LAN technologies on the IEEE 802.15.4 in the 2.4 GHz ISM band. We have specifically focused on IEEE 802.11g and pre-standard IEEE 802.11n products as potential interferers. Our measurements show that high levels of network traffic interference from either of these technologies has disastrous impact on the performance of IEEE 802...
Wireless ad hoc network is a dynamic network with the commitment of cooperative nodes. Multicasting is intended for group communication that supports the dissemination of information from a sender to all the receivers in a group. The difficulties of ad hoc networks are the scarcity of bandwidth, short lifetime due to power constraint, dynamic topology caused by nodes' mobility, etc. These problems...
Leader election is one of the most frequently encountered problems in peer-to-peer applications. However, choosing the best node is not a trivial problem and the obtained performance can dramatically vary depending on it. Another issue is what to measure in the evaluation and comparison of different leader election schemes. It is not clear yet what metrics best capture the performance objective. In...
Peer-to-peer is a popular distributed system. Mobile ad hoc networks and peer-to-peer file sharing systems both lack fixed infrastructure and hold no a- priori knowledge of arriving and departing peers. Due to this common nature, P2P file sharing seems natural and attractive to be deployed for MANET. But, the resource constraints such as bandwidth, computing power, energy, etc. and node's mobility...
In this paper, we use the Markov Decision Process (MDP) technique to find the optimal code allocation policy in High-Speed Downlink Packet Access (HSDPA) networks. A discrete stochastic dynamic programming model for the HSDPA downlink scheduler is presented. The model then is solved numerically using value iteration. The system performance when using the resulted optimal policy as compared to Round...
The interference imposes a potential negative impact on the performance of a wireless network. A device is interfered if it receives a transmission not intended for it. In this paper, we introduce an explicit computation model of node interference based on its actual inducement on the physical layer. We prove that there exists an optimal algorithm to solve the corresponding topology control problem,...
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