Showing papers in "Communications and Network in 2012"

Gender Identification on Twitter Using the Modified Balanced Winnow

Abstract: With the rapid growth of web-based social networking technologies in recent years, author identification and analysis have proven increasingly useful. Authorship analysis provides information about a document’s author, often including the author’s gender. Men and women are known to write in distinctly different ways, and these differences can be successfully used to make a gender prediction. Making use of these distinctions between male and female authors, this study demonstrates the use of a simple stream-based neural network to automatically discriminate gender on manually labeled tweets from the Twitter social network. This neural network, the Modified Balanced Winnow, was employed in two ways; the effectiveness of data stream mining was initially examined with an extensive list of n-gram features. Feature selection techniques were then evaluated by drastically reducing the feature list using WEKA’s attribute selection algorithms. This study demonstrates the effectiveness of the stream mining approach, achieving an accuracy of 82.48%, a 20.81% increase above the baseline prediction. Using feature selection methods improved the results by an additional 16.03%, to an accuracy of 98.51%.

Model Based Data Transmission: Analysis of Link Budget Requirement Reduction

Abstract: Communications capability can be a significant constraint on the utility of a spacecraft. While conventionally enhanced through the use of a larger transmitting or receiving antenna or through augmenting transmission power, communications capability can also be enhanced via incorporating more data in every unit of transmission. Model Based Transmission Reduction (MBTR) increases the mission utility of spacecraft via sending higher-level messages which rely on preshared (or, in some cases, co-transmitted) data. Because of this a priori knowledge, the amount of information contained in a MBTR message significantly exceeds the amount the amount of information in a conventional message. MBTR has multiple levels of operation; the lowest, Model Based Data Transmission (MBDT), utilizes a pre-shared lower-resolution data frame, which is augmented in areas of significant discrepancy with data from the higher-resolution source. MBDT is examined, in detail, herein and several approaches to minimizing the required bandwidth for conveying data required to conform to a minimum level of accuracy are considered. Also considered are ways of minimizing transmission requirements when both a model and change data required to attain a desired minimum discrepancy threshold must be transmitted. These possible solutions are compared to alternate transmission techniques including several forms of image compression.

An Improved Artificial Immune System-Based Network Intrusion Detection by Using Rough Set

Abstract: With theincreasing worldwide network attacks, intrusion detection (ID) hasbecome a popularresearch topic inlast decade.Several artificial intelligence techniques such as neural networks and fuzzy logichave been applied in ID. The results are varied. Theintrusion detection accuracy is themain focus for intrusion detection systems (IDS). Most research activities in the area aiming to improve the ID accuracy. In this paper, anartificial immune system (AIS) based network intrusion detection scheme is proposed. An optimized feature selection using Rough Set (RS) theory is defined. The complexity issue is addressed in the design of the algorithms. The scheme is tested on the widely used KDD CUP 99 dataset. The result shows that theproposed scheme outperforms other schemes in detection accuracy.

L(0, 1)-Labelling of Cactus Graphs

Abstract: An L(0,1)-labelling of a graph G is an assignment of nonnegative integers to the vertices of G such that the difference between the labels assigned to any two adjacent vertices is at least zero and the difference between the labels assigned to any two vertices which are at distance two is at least one. The span of an L(0,1)-labelling is the maximum label number assigned to any vertex of G. The L(0,1)-labelling number of a graph G, denoted by λ0.1(G) is the least integer k such that G has an L(0,1)-labelling of span k. This labelling has an application to a computer code assignment problem. The task is to assign integer control codes to a network of computer stations with distance restrictions. A cactus graph is a connected graph in which every block is either an edge or a cycle. In this paper, we label the vertices of a cactus graph by L(0,1)-labelling and have shown that, △-1≤λ0.1(G)≤△ for a cactus graph, where △ is the degree of the graph G.

Design of Broadband RoF PON for the Last Mile

Abstract: An increase in the demand of broadband service has encouraged research and study to find a solution to offer an adequate amount of service. Living in this digital world with downloading video, voice or data leads us occasionally to have a shortage of bandwidth in the provided data. One of the solutions to cover the huge expected demand in the future is improving the communication systems by adding optical passive components to the Radio over Fiber (RoF) system. This work is mainly to increase the bandwidth that allows the small and single consumer at the last mile. We have shown that by adding the 40-GHz mm-wave to the system, Bit-Error-Rate (BER) has increased while Q-factor has decreased.

Network Connectivity Probability of Linear Vehicular Ad-Hoc Networks on Two-Way Street

Abstract: In this paper, we present an analytical model to determine the network connectivity probability of a linear vehicular ad hoc network (VANET) formed by communication equipped vehicles on a two-way street scenario. We consider the highway to be consisting of two lanes with vehicles moving in both directions on these lanes and focus on the probability of being able to convey messages from a source vehicle to a destination vehicle, which may be multiple hops away. Closed form analytical expression is obtained for the network connectivity probability in the presence of Nakagami fading channel. In our model, the transmission range of each vehicle is modeled as a random variable due to channel fading. The analytical results are validated by extensive simulations.

Energy Efficient Non-Cooperative Methods for Resource Allocation in Cognitive Radio Networks

Abstract: In a cognitive radio network wherein primary and secondary users coexist, an efficient power allocation method represents one of the most important key aspects. This paper provides a novel approach based on a game theory framework to solve this problem in a distributed and fair way. Formulated as an optimization problem, the resource allocation problem between secondary users and primary users can be modeled and investigated with the Game Theory, and in particular S-Modular Games, since they provide useful tools for the definition of multi objective distributed algorithms in the context of radio communications. This paper provides also a performance comparison among the proposed game and two other algorithms, frequently used in this context: Simulated Annealing and Water Filling.

Load Balancing in IP/MPLS Networks: A Survey

Abstract: The present era has witnessed tremendous growth of the Internet and various applications that are supported by it. There is an enormous pressure on Internet Service Providers (ISPs) to make available adequate services for the traffics like VoIP and Video on demand. Since the resources like computing power, bandwidth etc. are limited, the traffic needs to be engineered to properly exploit them. Due to these limitations, terms like Traffic Engineering, Quality of Service (QoS) came into existence. Traffic Engineering broadly includes techniques like multipath routing & traffic splitting to balance the load among different paths. In this document, we survey various techniques proposed for load balancing that are available on the Internet. We here try not to be exhaustive but analyze the important techniques in the literature. Present survey would help to give a new direction to the research in this realm.

A Novel Offline PLI-RWA and Hybrid Node Architecture for Zero Blocking and Time Delay Reduction in Translucent Optical WDM Networks

Abstract: In this paper, we contrive a model that underpins the offline Physical Layer Impairment-Routing and Wavelength Assignment (PLI-RWA) issue in translucent networks. We introduce an innovative PLI-Signal Quality Aware RWA (PLI-SQARWA) algorithm that (a) guarantees zero blocking due to signal degradation and wavelength contention and (b) aims at minimizing the total required number of network components i.e. regenerators and all-optical wavelength converters (AOWCs). Further, in view of reducing the time delay due to optical-electrical-optical (OEO) conversions, we propose a novel electro-optical hybrid translucent node architecture. We show that PLI-SQARWA outperforms a recent heuristic for RWA and regenerator placement (RP) in terms of capital expenditure (CapEx) and time delay; while demonstrating superior blocking performance at all traffic loads. In addition, at high traffic loads, PLI-SQARWA also starts to provision savings on operational expenditure (OpEx). We proceed to the performance comparison of network equipped with the proposed hybrid node and existing translucent and transparent node architectures. The results clearly show that use of the hybrid node incurs less time delay at a similar blocking performance shown by nodes which use OEO conversion for both, regeneration and/or wavelength conversion. The results presented also highlight the significance of equipping the PLI-RWA routing phase with signal quality awareness in order to reduce the network component count and the use of AOWCs to minimize time delay due to OEO conversions.

Pilot Based Channel Estimation in Broadband Power Line Communication Networks

Abstract: In this paper pilot based channel estimation is being considered for broadband power line communication (BPLC) networks witch used orthogonal frequency division multiplexing (OFDM) in order to transmit high rate data. To estimate channel in time or frequency some pilot must be used. Number of these pilots and deployment of them is very important for proper estimation in different channel with varying time and frequency. Carrier sense multiple access (CSMA) and hybrid multiple access protocol are taken into consideration in MAC sub-layer. Multilayered perceptions neural network with backpropagation (BP) learning channel estimator algorithm with different pilot deployment compare to classic algorithm in for channel estimating. Simulation results show the proposed neural network estimation decreases bit error rate and therefore network throughput increases.

Optimal Number of Relays in Cooperative Communication in Wireless Sensor Networks

Abstract: Wireless Sensor Networks (WSN) typically consist of resource constrained micro sensors that organize itself into multihop wireless network. Sensors collect data and send it directly, or through intermediate hops in cooperative communication system, to the collection point. These sensors are powered up by batteries, for which the replacement or recharging is very difficult. With finite energy, we can transmit a finite amount of information. Therefore, minimizing the power consumption for data transmission becomes a most important design consideration for wireless sensor networks. In this paper, we discuss the optimal power consumption in cooperative wireless sensor network that are placed on a grid. We study different cases for the optimal power consumption in such grids by varying the grid distance and number of nodes in the grid. We assume the cases of grids from 2 × 2 up to 5 × 5 in increasing complexity of calculations. The results show that the optimal path that consumes the least power is the path along the diagonal using of the grid when the source and the destination and the furthest two nodes in the grid. This path takes intermediate nodes (relays) along it based on some threshold distances. For example, in 5 × 5 cases; the first threshold between the direct distance and between using one relay in the middle is 31.6 m the second threshold distance is 63.3 m after which using three relays is the best in power consumption between the source and the destination.

P2P Business Applications: Future and Directions

Abstract: Since the launch of Napster in June 1999, peer-to-peer technology (P2P) has become synonymous with file sharing applications that are the bane of the recording industry due to copyright infringements and consequent revenue losses. P2P promised a revolution in business computing which has not arrived. It has become synonymous with illegal file sharing and copyright violations. Meanwhile the information systems industry has undergone a paradigm change, and we are supposedly living in a world of cloud computing and mobile devices. It is pertinent to examine if P2P, as a revolutionary technology, is still relevant and important today and will be in future. One has to examine this question in the context of the fact that P2P technologies have matured but have however had limited adoption outside file sharing in the consumer space. This paper provides a detailed analysis of P2P computing and offers some propositions to answer the question of the relevancy of P2P. It is proposed that P2P is still a relevant technology but may be reshaped in the coming years in a different form as compared to what exists today.

Optimization of Security Communication Wired Network by Means of Genetic Algorithms

Abstract: The realization of security wired network is very critical when the network itself must be installed in an environment full of restrictions and constrains such as historical palaces, characterized by unique architectural features. The purpose of this paper is to illustrate an advanced installation design technique of security wired network based on genetic algorithm optimisation that is capable of ensuring high performances of the network itself and significant reduction of the costs. The same technique can be extended to safety system such as fire signalling.

Inter-Network Resource Sharing in IEEE 802.22 Networks

Abstract: IEEE 802.22 is the first worldwide standard for Cognitive Networks (CNs) that exploits unused spectrum of the television broadcast service. An IEEE 802.22 network is also called Wireless Regional Area Network (WRAN). An open issue in cognitive 802.22 networks is represented by the resource distribution among WRANs. In this paper a protocol for radio resource management for CNs in a multichannel environment is presented and analysed. In particular, the contribution of this work is a resource sharing method to schedule the WRAN access to the available channels in a community made by two o more coexisting WRANs. The method adapts to the continuous changes of the spectrum availability due to necessity of vacating a channel in case of the incumbent primary users. Moreover, the introduced allocation scheme allows to divide the available band in a proportional way to the cognitive user spectrum demands, taking into account the issue of spatial diversity, i.e. the case where the channel coverage area is not uniform. The effectiveness of the proposed multichannel scheme is proved through simulations. The results compared favorably with other methods already known in literature and show that the proposed algorithm optimize the spectral efficiency, keeping high fairness as demonstrated computing the Jain’s index.

A New Energy Efficient Data Gathering Approach in Wireless Sensor Networks

Abstract: Data gathering in wireless sensor networks is one of the important operations in these networks. These operations require energy consumption. Due to the limited energy of nodes, the energy productivity should be considered as a key objective in design of sensor networks. Therefore the clustering is a suitable method that used in energy consumption management. For this purpose many methods have been proposed. Between these methods the LEACH algorithm has been attend as a basic method. This algorithm uses distributed clustering method for data gathering and aggregation. The LEACH-C method that is the improvement of LEACH, which performs the clustering in centralized mode. In this method, collecting the energy level of information of every node directly in each period increases the energy cost. Also the phenomenon that is seen by sensor nodes continually change over time. Thereby the information received by nodes is correlated. Sending time correlated data in the network cause to energy dissipation. TINA method and its improvement have been proposed in order to not sending correlated data. These approaches have reported errors. In this paper, the idea of not sending time correlated data of nodes has been considered by using the time series function. Also, a model to estimate the remaining energy of nodes by the base station has been presented. Finally, a method has been proposed to aware the base station from the number of correlated data in each node as the estimation of energy will be more precise. The proposed ideas have been implemented over the LEACH-C protocol. Evaluation results showed that the proposed methods had a better performance in energy consumption and the lifetime of the network in comparison with similar methods.

A Service Discovery Approach Based on a Quantitative Similarity Measure for M-Tourism Platforms

Abstract: This paper presents a localization architecture for an m-tourism services delivery platform. The aim of the system is to deliver services for nomads (e-tourists) according to their localization and according to the results given by the search engine. This engine is based on a quantitative similarity measure. The discovered services are presented via a Web Map Service. Moreover, the platform integrates an adaptation sub-system for heterogeneous environments and an e-negotiation module.

Homogeneous and Heterogeneous Traffic of Data Packets on Complex Networks: The Traffic Congestion Phenomenon

Abstract: We study the congestion phenomenon in a mathematical model of the data packets traffic in transmission networks as a function of the topology and of the load of the network. Two types of traffic are considered: homogeneous and heterogeneous traffic. The congestion phenomenon is studied in stationary conditions through the behaviour of two quantities: the mean travel time of a packet and the mean number of packets that have not reached their destination and are traveling in the network. We define a transformation that maps a network having the small world property (Inet 3037 in our numerical experiments) into a (modified) lattice network that has the same number of nodes. This map changes the capacity of the branches of the graphs representing the networks and can be regarded as an “interpolation” between the two classes of networks. Using this transformation we compare the behaviour of Inet 3037 to the behaviour of a modified rectangular lattice and we study the behaviour of the interpolating networks. This study suggests how to change the network topology and the branch capacities in order to alleviate the congestion phenomenon. In the website: http://www.ceri.uniroma1.it/ceri/zirilli/w6 some auxiliary material including animations and stereo?graphic scenes that helps the understanding of this paper is shown.

Layer-Wise Topology Design for Cost Effective IP-Optical Networks

Abstract: Traffic engineering and topology design considering multilayer configuration have become more important. While multilayer design studies usually discuss the traffic engineering issue or reliability, this paper focuses on network construction cost in studying multilayer topology design. The number of ports for the IP layer and the maximum number of Wavelength Division Multiplexers (WDM) for the optical layer are used as construction cost factors. Given a traffic matrix for the IP layer, 1) the number of ports is minimized to obtain a topology and a traffic matrix for the optical link, and 2) the maximum number of WDMs is minimized to configure the optical layer topology. It is shown that both the IP and Optical path layers have been given economic topologies. We present LP formulations of this scheme and the results of a simulation of the full-mesh traffic of 5 nodes, which shows that both layers are successfully optimized.

Performance Evaluation of Traffic Engineering Signal Protocols in IPV6 MPLS Networks

Abstract: This paper studies the performance of Traffic Engineering (TE) signal protocols used for load balancing in Multi-Protocol Label Switching (MPLS) networks, namely; Constraint Based Routed Label Distribution Protocol LDP (CR-LDP) and Resource Reservation Protocol (RSVP). Furthermore, the performance of an MPLS network uses these TE signal protocols is compared to that of a conventional Internet Protocol (IP) network. Different applications including voice, video, File Transfer Protocol (FTP) and Hyperlink Text Transfer Protocol (HTTP) are used for the performance evaluation. Simulation results show superior performance of the MPLS network with CR-LDP TE signal protocol in all tested applications.

Design of Network Architecture Using Mobile Gateways for DLNA Devices in Wide Area Networks

Abstract: The prevalence of information appliances supporting DLNA (Digital Living Network Alliance) such as televisions, recorders, and mobile phones has made it possible to share digital contents (eg videos, music and pictures) among appliances connected to a local network However, DLNA does not let you share contents over different networks via the Internet In this paper, we propose a network architecture where we adopt our SOAP method to mobile devices and use them as mobile gateways to consume digital contents from remote networks We also confirm its practicality with a prototype

Cognitive Radio Ad-Hoc Networks: Some New Results on Multi-Channel Hidden Terminal Problem

Abstract: Recently the Cognitive Radio (CR), in particular the CR Ad-Hoc Network (CRAHN) technology appears as a burgeoning area in wireless communication that enables utilization of limited network resources in more efficient and intelligent way; studies indicate that opportunistic utilization of the available radio frequency spectrum, without interfering the licensed primary user (PU) could be made. This paper presents some simulation based performance of the Multi-Channel Hidden Terminal (MCHT) problem on CRAHNs; new observations on the effect of the number of channels on certain PU-activity metrics, e.g., delay and throughput, are described.

The Tight Bound for the Number of Pilots in Channel Estimation for OFDM Systems

Abstract: Coherent detection in OFDM systems requires accurate channel state information (CSI) at the receiver Channel estimation based on pilot-symbol-assisted transmissions provides a reliable way to obtain CSI Use of pilot symbols for channel estimation, introduces overhead and it is desirable to keep the number of pilot symbols as minimum as possible This paper introduces a new tight bound for the number of pilots in channel estimation using adaptive scheme in OFDM systems We calculate the minimum number of necessary pilots using two approaches The first approach for the number of pilots is obtained based on Doppler frequency shift estimation and the second approach is acquired based on channel length estimation using second order statistics of received signal Finally we obtain the tight bound for the number of pilots using attained values

General Purpose Wireless Communication System Using Data Acquisition

Abstract: A sensor-enabled and RFID-integrated, Wireless Data Acquisition System (WDAS) that has similar functionality as multiple input multiple output (MIMO) systems for health-care applications has been developed, simulated and implemented. The system can accept various measurements via sensors placed on patients or elders and transmit information wirelessly to base station at a remote location. A microcontroller is used to control and process the signals submitted from sensor-enabled RFID devices using sequential logic. Processed signals are then sent to single receiver and transmitter pair instead of conventional MIMO antenna systems. This reduces the cost significantly in comparison to existing systems. It has been shown that the data transmitted from measurement locations can be acquired at the base station located 20 mile away. Data acquisition system (DAQ) is used to determine the measured value, apply the required statistics and display information to health-care professional at the base station. The system developed can be used for health-care applications including nursing homes in rural areas where access is difficult.

MAC-PHY Cross-Layer for High Channel Capacity of Multiple-Hop MIMO Relay System

Abstract: For the high end-to-end channel capacity, the amplify-and-forward scheme multiple-hop MIMO relays system is considered. The distance between each transceiver is optimized to prevent some relays from being the bottleneck and guarantee the high end-to-end channel capacity. However, in some cases, the location of relays can’t be set at the desired location, the transmit power of each relay should be optimized. Additionally, in order to achieve the higher end-to-end channel capacity, the distance and the transmit power are optimized simultaneously. We propose the Markov Chain Monte Carlo method to optimize both the distance and the transmit power in complex propagation environments. Moreover, when the system has no control over transmission of each relay, the interference signal is presented and the performance of system is deteriorated. The general protocol of control transmission for each relay on the MAC layer is analyzed and compared to the Carrier Sense Multiple Access-Collision Avoidance protocol. According to the number of relays, the Mac layer protocol for the highest end-to-end channel capacity is changed. We also analyze the end-to-end channel capacity when the number of antennas and relays tends to infinity.

Solutions Comparison towards Voice Services Implementation for Operators Starting LTE Deployment

Abstract: The continuity of voice services, for many operators planning to start their LTE network, is one of the key requirements to cover back the cost of this expensive network. In this paper, we discuss and compare the possible solutions to add voice services on an LTE network dedicated mainly for high-speed data transfer. By comparing advantages and inconvenient of the existing approaches, we conclude that the selection of the One Voice approach is obvious, especially for operators starting LTE deployments, the One Voice approach has the support of all the famous operators and vendors. Selecting the One Voice approach as a first alternative was evident, but the choice of CSFB as a mid-term solution or backup solution from many operators was not clear. As a key lesson can be learned from the existing technologies, CDMA and GSM, where the type of handset was one of the major factors of the GSM success; we prove in this paper that VOLGA approach is better than CSFB for many reasons: The VOLGA approach uses less complex and less expensive handset while it gives more comfortable user experience compared to CSFB approach, so operators should take into consideration these two points before selecting the second alternative.

Utilizing Colored Pheromones and Helping Ants for Wireless Mesh Networks Routing

Abstract: Improving routing algorithm performance not only leads to appreciate the quality of data transmission, but also increases the speed of data transfer. In this paper we propose a hybrid method which is a combination of traffic classification by the help of colored pheromones and helping ants method in the intermediate nodes. This combination increases the convergence speed and decreases the delay and Jitter in the network. Also we compare the obtained results with two known routing algorithms that are based on the ant colony.

NAMD Package Benchmarking on the Base of Armenian Grid Infrastructure

Abstract: The parallel scaling (parallel performance up to 48 cores) of NAMD package has been investigated by estimation of the sensitivity of interconnection on speedup and benchmark results—testing the parallel performance of Myrinet, Infiniband and Gigabit Ethernet networks The system of ApoA1 of 92 K atoms, as well as 1000 K, 330 K, 210 K, 110 K, 54 K, 27 K and 16 K has been used as testing systems The Armenian grid infrastructure (ArmGrid) has been used as a main platform for series of benchmarks According to the results, due to the high performance of Myrinet and Infiniband networks, the ArmCluster system and the cluster located in the Yerevan State University show reasonable values, meanwhile the scaling of clusters with various types of Gigabit Ethernet interconnections breaks down when interconnection is activated However, the clusters equipped by Gigabit Ethernet network are sensitive to change of system, particularly for 1000 K systems no breakdown in scaling is observed The infiniband supports in comparison with Myrinet, make it possible to receive almost ideally results regardless of system size In addition, a benchmarking formula is suggested, which provides the computational throughput depending on the number of processors These results should be important, for instance, to choose most appropriate amount of processors for studied system

Training Based Channel Estimation in MIMO-OFDM Systems

Abstract: OFDM combined with the MIMO technique has become a core and attractive technology in future wireless communication systems and can be used to both improve capacity and quality of mobile wireless systems Accurate and efficient channel estimation plays a key role in MIMO-OFDM communication systems, which is typically realized by using pilot or training sequences by virtue of low complexity and considerable performance In this paper, we discuss some methods for channel estimation based training symbols in MIMO-OFDM systems The results confirm the superiority of the represented methods over the existing ones in terms of bandwidth efficiency and estimation error

An Improved Name Disambiguation Method Based on Atom Cluster

Abstract: An improved name disambiguation method based on atom cluster. Aiming at the method of character-related properties of similarity based on information extraction depends on the character information, a new name disambiguation method is proposed, and improved k-means algorism for name disambiguation is proposed in this paper. The cluster analysis cluster is introduced to the name disambiguation process. Experiment results show that the proposed method having the high implementation efficiency and can distinguish the different people with the same name.

An Investigation on the Effect of Migration Strategy on Parallel GA-Based Shortest Path Routing Algorithm

Abstract: Genetic algorithm (GA) is one of the alternative approaches for solving the shortest path routing problem. In previous work, we have developed a coarse-grained parallel GA-based shortest path routing algorithm. With parallel GA, there is a GA operator called migration, where a chromosome is taken from one sub-population to replace a chromosome in another sub-population. Which chromosome to be taken and replaced is subjected to the migration strategy used. There are four different migration strategies that can be employed: best replace worst, best replace random, random replace worst, and random replace random. In this paper, we are going to evaluate the effect of different migration strategies on the parallel GA-based routing algorithm that has been developed in the previous work. Theoretically, the migration strategy best replace worst should perform better than the other strategies. However, result from simulation shows that even though the migration strategy best replace worst performs better most of the time, there are situations when one of the other strategies can perform just as well, or sometimes better.