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ABSTRACT: Recently, the number of spam mails is exponentially growing. It affects the costs of organizations and annoying the e-mail recipient. Spammers always try to find the way to avoid filtering out from the email system. At the same time, as an email recipient or network system/administrator, we try to have an effective spam mail filtering technique to catch the spam mails. The problems of spam mail filtering are that each user has different perspective toward spam mails; so there are many types of spam mails, while the challenge is how to detect the various types and forms of spam mails. In this paper, behaviors of spammers are used to customize the filtering rule. The information from the spam messages also can be used to filter spam mails and it can give higher accuracy than the keyword-based method does. We propose a spam classification approach using Random Forest algorithm. Spam Assassin Corpus is selected as a database for classification. It consists of 6,047 email messages, where 4,150 of them are the legitimate messages and the other 1,897 messages are the spam mails.
Networked Computing (INC), 2010 6th International Conference on; 06/2010
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ABSTRACT: Network design problem is usually complicated. Network designers may have to optimize various design objectives simultaneously. This paper considers a multi-objective network design problem for routing wavelength assignment (RWA) in WDM networks. The design objectives are to maximize the number of accepted communication requests (source-destination pairs) as well as to minimize the number of wavelength channel requirement subject to a limited number of wavelength channels available on each network link and at least 80% of all commodities must be accepted. Both the design objectives are conflicted to each other; maximizing the number of accepted commodities will require a large number of wavelength channels while minimizing the number of wavelength channels will limit the amount of accepted commodities. To solve the problem, we apply a famous multi-objective optimization approach called "SPEA2". The obtained results are compared with those from the Weighted Sum Approach in various weighted cases. The result comparisons show that the SPEA2 is superior in term of providing various sets of feasible solutions as a front in the objective space.
Communications and Information Technology, 2009. ISCIT 2009. 9th International Symposium on; 10/2009
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ABSTRACT: Together with the extensive deployment of computer networks, the number of network attacks is greatly increasing. These attacks affect to availability and quality of services of the networks as well as confidentiality of private or important information data. In this paper, we present two network intrusion detection (IDS) techniques which are C4.5 decision tree and Ripper rules to assess and test an online dataset(RLD09 dataset). The dataset was collected from actual environment and then preprocessed to have only 13 features which are much simpler than existing traditional dataset such as KDD99 with 41 features. Thus, the RLD09 dataset features can provide real-time detection speed with low memory and CPU consumption. Our IDSs can classify the network data into classes which are normal data, denial of service (DoS) attack, and Probe (Port Scanning) attack. Our IDS techniques give the detection rates higher than 98%. Furthermore, they can detect unknown or new attacks, where the C4.5 decision tree detection rate is about the double of the Ripper rule detection rate. These tests can prove that our techniques are effective in detecting and classifying the new unknown attacks in the real environment.
Communications and Information Technology, 2009. ISCIT 2009. 9th International Symposium on; 10/2009
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ABSTRACT: The issues of network performance and reliability in wireless access networks have become indispensable due to the increasing needs for communication services anywhere and anytime. Traditional design of wireless backhaul networks has a simple tree-like structure which is vulnerable to network failures. To protect services against network component/facility breakdown, reliable network design is required. However, the complexity of reliable network design is a well-known problem. Various techniques have been proposed to find a minimum-cost solution in a reliable network design. In this paper, we propose and compare two different approaches which are network link restoration and network path restoration for reliable wireless backhaul network design. These restoration techniques provide fault tolerance to tree topology in traditional cellular network design, so that any breakdown of single link or multiple links within a network path can no longer interrupt the network services. As a result, the network design with backup path using restoration approaches can greatly enhance the network reliability and quality of services. We also show that a well-known shortest path algorithm can be efficiently applied as a meta-heuristic technique for both link restoration and path restoration approaches in a reliable wireless backhaul network design.
Communications and Information Technologies, 2008. ISCIT 2008. International Symposium on; 11/2008
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ABSTRACT: This paper presents a survivable network design using network path restoration approach to provide fault tolerance in cellular backhaul network design, so that any breakdown of links within a network path can no longer interrupt the network services. As a consequence, the network design can greatly enhance the network reliability and quality of services. We adopt a two-phase network design approach to reduce the complexity of network design and to provide a design mechanism for enhancing reliability in existing networks. The first phase provides a minimum-cost initial network design. The problem is to find a minimum-cost network topology which includes selecting the location and type of base station controllers and mobile switching controllers as well as their link types. The second phase provides backup paths and spare capacity to the network topology from phase one to improve network reliability. Due to the complexity of network design problem, a genetic algorithm is applied as a meta-heuristic technique for obtaining good solutions. Various problem sizes of example networks are considered and discussed.
Availability, Reliability and Security, 2008. ARES 08. Third International Conference on; 04/2008
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ABSTRACT: In this paper, we propose an optimization based model for the design of survivable third generation wireless access backhaul networks using a mesh topology. The network design model seeks to minimize the cost of the backhaul network while meeting quality of service and survivability requirements. The design model includes the packet based nature of network traffic and incorporates the effects of user mobility after a failure. We adopt a two-phase design methodology. The first phase provides a minimum-cost, initial network design meeting QoS requirements. The second phase augments the network topology from phase one in order to satisfy survivability requirements. In order to scale the design with network size a computationally efficient heuristic based on iterative minimum cost routing is proposed. Numerical results are given illustrating the network design approach and the quality of the heuristic solution method.
Design of Reliable Communication Networks, 2005. (DRCN 2005). Proceedings.5th International Workshop on; 11/2005
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ABSTRACT: In wireless access network design, a tree-like topology is usually used due to its minimum connectivity and the economy of scale on network link costs. However, the tree topology is vulnerable to any single link/component failure. There are several strategies in designing a reliable network topology. This paper gives reliability analysis of typical wireless access network topologies, which are spanning tree, ring and multiring. We present a reliable network design model for wireless backhaul network design based on the multiring network topology. We formulate the problem of reliable wireless backhaul network design as a mixed integer-programming model to minimize the network cost while satisfying traffic requirements.
TENCON 2004. 2004 IEEE Region 10 Conference; 12/2004
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C. Charnsripinyo
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ABSTRACT: Wireless access networks have importantly become a part of the telecommunication infrastructure that provides voice, data and multimedia services to mobile users. As traffic increasingly becomes data instead of voice, existing wireless access networks need an appropriate and efficient infrastructure for the delivery of bursty data packet services. This paper presents a network optimization model for topological design of 3G wireless access networks. The main objective of the model is to optimize the network design cost of 3G wireless backhaul networks with acceptable quality of service requirements. This paper also presents an efficient heuristic method to solve large network design problem sizes within a reasonable computational time while obtaining a near optimal solution.
TENCON 2004. 2004 IEEE Region 10 Conference; 12/2004
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ABSTRACT: Wireless mobile networks have become crucial in providing untethered communication services to mobile users. In this paper, we propose an optimization model for the design of survivable wireless access networks. The main objective of the model is to optimize the network design cost of wireless backhaul networks while meeting survivability requirements. This paper also presents a simple and efficient heuristic method to solve the network design model for large network problem sizes within a reasonable computational time while obtaining a near optimal solution.
Design of Reliable Communication Networks, 2003. (DRCN 2003). Proceedings. Fourth International Workshop on; 11/2003
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ABSTRACT: An important issue in the widespread deployment of infrastructure based wireless local area networks (WLANs) is the network design. In this paper, we propose a new WLAN design approach that focuses on assuring sufficient data rate capacity to meet expected user demand in the coverage area, while still satisfying signal coverage and interference level requirements. Noting the low cost of WLAN access points, we formulate a novel mathematical network design model within the framework of constraint satisfaction problems. Our model is termed the capacity based WLAN constraint satisfaction problem (Cap-WLAN CSP). The solution of the Cap-WLAN CSP model yields a network design based on data rate demand by providing the access point locations, the frequency channel allocation, and power levels required for the WLAN to meet expected user demands. Our numerical results illustrate that the capacity based approach is more appropriate for the design of WLAN systems than those of traditional coverage based designs.
MILCOM 2002. Proceedings; 11/2002
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ABSTRACT: Providing fault tolerance in wireless access networks has become crucial as user dependence on mobile services increases, especially for business and emergency services. Unlike wired access networks, fault tolerant wireless network design can be costly, and highly complicated due to unique characteristics of wireless mobile networks, such as user mobility, that can significantly worsen network performance after failures. We present a novel network design model that incorporates the effect of user mobility for fault-tolerant wireless access networks. The problem was formulated as an integer programming (IP) model to minimize the total network interconnect cost while user demands and survivability requirements are satisfied.
MILCOM 2002. Proceedings; 11/2002
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ABSTRACT: Research and development on network survivability has largely
focused on public switched telecommunications networks and high-speed
data networks with little attention on the survivability of wireless
access networks supporting cellular and PCS communications. This article
discusses the effects of failures and survivability issues in PCS
networks with emphasis on the unique difficulties presented by user
mobility and the wireless channel environment. A simulation model to
study a variety of failure scenarios on a PCS network is described, and
the results show that user mobility significantly worsens network
performance after failures, as disconnected users move among adjacent
cells and attempt to reconnect to the network. Thus, survivability
strategies must be designed to contend with spatial as well as temporal
network behavior. A multilayer framework for the study of PCS network
survivability is presented. Metrics for quantifying network
survivability are identified at each layer. Possible survivability
strategies and restoration techniques for each layer in the framework
are also discussed
IEEE Communications Magazine 02/2002; · 3.79 Impact Factor
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ABSTRACT: Research and development on network survivability has largely focused on public switched telecommunications networks and high-speed data networks with little attention on the survivability of wireless access networks supporting cellular and PCS communications. This paper discusses the effects of failures and survivability issues in PCS networks with emphasis on the unique difficulties presented by user mobility and the wireless channel environment. A simulation model to study a variety of failure scenarios on a PCS network is described and the results show that user mobility significantly worsens network performance after failures, as disconnected users move among adjacent cells and attempt to reconnect to the network. Thus survivability strategies must be designed to contend with spatial as well as temporal network behavior. A multi-layer framework for the study of PCS network survivability is presented. Metrics for quantifying network survivability are identified at each layer. Possible survivability strategies and restoration techniques for each layer in the framework are also discussed.
11/2001;
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IEEE Communications Magazine. 40(1):58-65.
