Volume 4, Issue 7, July 2012


Parallel Computing Solution for Capacity Expansion Network Flow Optimization Problems
Arun Somani and Jinxu Ding

In classical linear network flow (LNF) problems, a network consists of multiple source and sink nodes, where each node is a sink node or a source node, but not both. Usually, there is only one kind of commodity flow and the goal is to find flow schedules and routes such that all sink nodes’ flow demands are satisfied and the total flow transmission cost is minimized. We develop a capacity expansion multicommodity network flow (CEMNF) problem, in which the total commodity supply is less than the total commodity demand. There are more than one kind of commodities and each node is a commodity flow generator, as well as a consumer. It is allowed to do expansion for commodity flow generation capacities at each node and also to do expansion for commodity flow capacities of each arc so that more flow can be transmitted among nodes. Thus, CEMNF is not only a commodity flow routing problem, but also a commodity generation and flow planning problem, in which the increasing commodity demands need to be satisfied by generation/transmission capacity expansions. The goal of CEMNF problems is to find the flow routes and capacity expansion plans such that all flow demands are satisfied and the total cost of routing and planning is minimized. High-performance distributed computing algorithms have been designed to solve classical linear network flow (LNF) problems have been proposed. Solving the general CEMNF problems by high-performance distributed computing algorithms is an open research question. The LNF problems can be formulated as linear programming models and algorithms have been proposed to solve them efficiently on distributed computing platforms. But, the constraints of the CEMNF problems do not allow them to solve using the same methodology. In this paper, we also develop a transformation method to transform CEMNF problems into LNF problems in polynomial time and space complexity to solve them efficiently on distributed computing platforms. The results show that we can solve CEMNF problems with high performance.

Keywords: Augmented network flow problems, Classical linear network flow problems, Flow generation/transmission capacity expansions in network flow problems, High performance distributed computing solution to solve CEMNF problems

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Contribution to Contents Modeling in the Computing Environment for the Human Learning (CEHL)
M. ELammari, F. Khoukhi and A. Bekkhoucha

This paper presents the content model in our system SPACAM (educational system adaptive cognitive activ-ity and motivation). Its main objective is to facilitate the structuring of learning units to the teacher-producer of educa-tional materials. This model is inspired by recent works coming from the engineering in the field of learning. It allows the teacher to organize his/her pedagogy within contents while addressing the needs of learners. The resulting envi-ronment allows teachers to develop their scenarios by making explicit the various aspects related to the content model. To facilitate the design through reuse and adaptation, the environment imposes - at different levels of model-criteria (separation between activity and resources and between content and its scenario) according to two aspects: structuring and scenario creation.

Keywords: content model, CEHL, structuring, scenario, teaching strategies

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Performance Analysis of MANET under Wormhole Attack
Rajib Das, Bipul Syam Purkayastha

Now a days most of the people are going wireless, reducing the vulnerability of wireless networks is becoming a top priority. Wireless networks are susceptible to many attacks. We study routing misbehavior in MANETs (Mobile Ad Hoc Networks) in this paper. In general, routing protocols for MANETs are designed based on the assumption that all participating nodes are fully cooperative. However, due to the open structure and scarcely available battery-based energy, node misbehaviors may exist. One such routing misbehavior is that some selfish nodes will participate in the route discovery and maintenance processes but refuse to forward data packets. The scope of this paper is to study the effects of Wormhole attack in MANET using two protocols DSR and WDSR. Comparative analysis of Wormhole attack for both protocols is taken into account. The impact of Wormhole attack on the performance of MANET is evaluated by finding out which protocol is more vulnerable to the attack and how much is the impact of the attack on both protocols. The measurements were taken in the light of throughput, end-to-end delay and network load. Analytical and simulation results are presented to evaluate the performance of the proposed scheme.

Keywords: Mobile Ad Hoc Networks (MANETs), routing misbehavior, Wormhole, WDSR, DSR

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Concept driven framework for Latent Table Discovery
Gowri Shankar Ramaswamy and F Sagayaraj Francis

Database systems have to cater to the growing demands of the information age. The growth of the new age information retrieval powerhouses like search engines has thrown a challenge to the data management community to come up with novel mechanisms for feeding information to end users. The burgeoning use of natural language query interfaces compels system designers to present meaningful and customised information. Conventional query languages like SQL do not cater to these requirements due to syntax oriented design. Providing a semantic cover over these systems was the aim of latent table discovery focusing on semantically connecting unrelated tables that were not syntactically related by design and document the discovered knowledge. This paper throws a new direction towards improving the semantic capabilities of database systems by introducing a concept driven framework over the latent table discovery method.

Keywords: Conceptual framework, Data semantics, Knowledge discovery, Knowledge engineering, Knowledge management

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Optimizing the architecture of Kohonen map and classification
M. Ettaouil, A. Essafi and F. Harchli

The Clustering is useful in data mining. It allows speeding up the search of relevant information. There exist many clustering algorithms in the literature. For instance, we find k-means which is the more former of them, and neural Kohonen network. Because of their efficacy, these algorithms are preferred in this domain. But their performance depends on the initialization phase. This drawback presents a great challenge to the searchers. In this vein, we propose in this work an approach able to improve the performance of neural Kohonen algorithm. This method consists to initialize the neurons of the map by some objects determinate in a preprocessing phase. The goal of neural Kokonen network is to regroups a set of data in unknown number of cluster. In practice, the task aims to search the prototypes of these classes. Initially, in classical algorithm these inputs are chosen randomly and updated after during the processing. Often this choice is not suitable and decreases the results. To alleviate this problem, we perform a first preprocessing. The goal in this phase is to look for the inputs around which there exist a lot of data. Then we initialize the neurons of the Kohonen map by these inputs. With this technique we attempt to realize two goals: the first is to improve the quality of the Kohonen algorithm, the second is to optimize the architecture of Kohonen map. Finally, to justify our approach, some experiments are performed.

Keywords: Clustering, Kohonen networks, Optimization of architectures and Unsupervised Learning

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Product Feature Extraction Using Natural Language Processing Techniques
Niloufar Salehi Dastjerdi, Roliana Ibrahim, and Seyed Hamid Ghorashi

Nowadays many customers use online services for buying their desired products and many products and services are sold through the Web. On the one hand, considerable numbers of people are expressing their opinion about a particular product or service by writing comments on them; and on the other hand, collecting user’s opinions and giving feedback to the service or product providers. These are important techniques of increasing the chance of business success and improving service quality. For this, identifying opinion sentences and extracting appropriate features of review sentences can be perceived as a proper task. This paper applies techniques of natural language processing for the detection of sentences expressing an opinion. Subsequently, product features can be identified in each opinion sentence, considering appropriate grammatical concepts in the review sentence. In this instance, the review sentences will be considered as an input and extracted features and opinions as an output. Finally the results and accuracy of the system will be measured by related evaluation metrics.

Keywords: Customer Reviews, Dependency Relation, NLP (Natural Language Processing), Product Feature

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Analysis of Security Attacks at different layers of TCP/IP Network Model
Khalid Saeed, Muhammad Adil, and Muhammad Saqib Awan

Security attacks are the main anxiety of almost every user of Internet or an organization’s network. Not even a single computer is 100% secure from security attacks. All that one can do is to minimize the impact of these attacks. The TCP/IP Network Model consists of four layers and the network faces different attacks at different layers of TCP/IP network model. The consequences of these attacks are different therefore these attacks are to be handled contrarily. This research studies and analyzes certain security attacks at different layers of TCP/IP network model, their consequences and the possible countermeasures in order to either eliminate or mitigate their effects.

Keywords: Security Attacks, TCP/IP Network Model, DNS Cache Poisoning, Trojan Horse, DOS Attack, Port Scanning, Session Hijacking, IP Spoofing, Packet Sniffing, ARP Cache Poisoning, MAC Address Spoofing

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Spectral Efficiency Analysis of MBOFDM UWB channel physical layer using ChDMA multiple access scheme
C. Houda, A. Hichem, and B. Ridha

MBOFDM has been recently presented as a promising radio technology for WPAN applications due to the signal robustness against the channel selectivity. In this paper, we propose an innovative scheme that exploits the user’s channels to guarantee multiple ac-cesses called Channel Division Multiple Access (ChDMA) originally introduced in [1]. The signature code is given by the CIR of each user; the analysis is focused in the MBOFDM multiple access channel performance evaluation. The aim of this paper is to study and propose an improvement of the MB-OFDM system which depends on the spectral efficiency (bps/s/hz). The spectral efficiency is investigated assuming Channel State Information (CSI) at the receiver. Additionally, the proposed multiple access scheme benefits from user’s position.

Keywords: High data rate, channel division multiple access, MBOFDM, multiple access schemes, optimal receive, spectral efficiency, WPAN

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Comparison of algorithms to maximize the lifetime of wireless sensor networks
Masood Mohammadi, Hamed Pezeshki ,Ali Akbar Arjomand Hashjin, Yaghoob Gharani Bonab, and Behzad Ghaffari

Power consumption in the sensor nodeis for the Sensing, Communication and Data Processing. More energy is required for data communication in sensors. So the major problem for Wireless Sensor Networks (WSN) is the limited energy supply of the sensors. The research in this area is focused on making smaller sensors with low power consumption. Some of the most common techniques in prolonging the lifetime of the sensor network are data compression, routing algorithms, data aggregation, scheduling and synchronization. This paper compares ARA algorithm with already existing algorithms for grid WSN and highlighting the advantages of using the routing algorithm together with the data aggregation technique.

Keywords: data aggregation, energy saving, grid wireless sensor network, routing algorithm

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Security Analysis of CARBAC Model in Pervasive Computing Environment Using Colored Petri Net
S. Tafkiki Alamdari, S. Pashazadeh and H. Mirzamohammadzadeh

With the rapid growth in computing technology, we are moving toward era of pervasive computing. Accuracy of access control mechanisms is a big challenge in these environments. A pervasive computing application commonly collects data from wide spectrum of resources, then processes them and distribute between different users. The major parts of traded data are so important that must be pro-tected. Till now, different models for user access control in pervasive computing are proposed and their features are being optimized every day. At this article, we model and verify security of a context aware role based access control (CARBAC) policy using Colored Petri Net. Our main purpose is to prove the accuracy and integrity of CARBAC and detecting the conflicts among its features. User’s time and location are environmental contexts that were involved in some decision-makings like user to roles assign, permissions to roles assign, permissions and roles hierarchy, and in separation of duties. We applied this model in design of university’s pervasive computing environment and then we created some queries in ML programming language for integrity analysis and verification of our model.

Keywords: Context Aware Role Based Access Control (CARBAC), Pervasive Computing Environment, Access Control Graph, Colored Petri Net, State Space Analysis

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Outlier modification in Fuzzy Linear Regression with Fuzzy input and output using Tw based arithmetic operations
B. Pushpa, R. Sattanathan and R. Vasuki

Fuzzy linear regression has been widely studied and applied in various areas. However Tanaka’s approach suffered the problem of extremely sensitive to the outlier. In this paper to handle the outlier problem, Chen’s approach is used along with Tw based arithmetic operations which can handle fuzzy input-fuzzy output dataset. Some numerical experiments are performed to assess the performance of the proposed approach.

Keywords: Fuzzy linear regression, Tw-based arithmetic operations, Fuzzy input and fuzzy output

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Quad Axis Separation Framework for Bounding-Volume Hierarchies Construction
Hamzah Asyrani Sulaiman, Abdullah Bade, Mohd Harun Abdullah

The construction of Bounding-Volume Hierarchies (BVH) for Virtual Environment application has been varied from the rigid bodies application type to the deformable bodies application. Numerous technique and specific instruction has been given from several researchers in order to make sure that the BVH can suite their application without any restriction. In this paper, we explore the capability of BVH using a technique called Quad Axis Separation Technique (QAS) that could efficiently create full-blown hierarchical tree using approximation of separating axes theorem for Virtual Environment. A theoretical implementation is carried out with standard experimental that is also been used by researcher to test their BVH in the Virtual Environment. We also believed that QAS could provide fast and efficient hierarchical tree construction and also enhance the speed and accuracy of the collision detection technique.

Keywords: Bounding-Volume Hierarchies, Collision Detection, Bounding-Volume, Virtual Environment

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Ns-2 flexibility in simulation of N-Dimensional hierarchical NoC architectures
Reza Kourdy and Mohammad Reza Nouri rad

In this paper, we study two N-Dimensional hierarchical structures for Network-on-Chip (NoC). The modern Chip Multiprocessor (CMP) designs are mainly based on the shared-bus communication architecture. As the number of cores increases, it suffers from high communication delays. Therefore, NoC based architecture is proposed. The main problem is limitation in NOC simulation. We simulate proposed architecture with Network Simulator-2 (NS2). The simulation results reveal the applicability of the proposed architecture. The focus of this paper is to show that the universal property of the N-Dimensional hierarchical NoC applies to distributed networks. We also carry out the high-level simulation of on chip network using NS2 to verify the analytical analysis.

Keywords: System on a chip (SoC), Network on Chip (NOC), Network AniMator (NAM), Digital Signal Processor (DSP), IP(Intellectual Property), network interface (NI), Globally Asynchronous Locally Synchronous (GALS)

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NoC-based Network Switching Node
Reza Kourdy and Mohammad Reza Nouri rad

A promising idea towards a more scalable solution is to replace the crossbar by a Network-on-Chip (NoC). In this paper we want to investigate the general feasibility of this approach and explore different NoC structures for the crossbar substitution. However, such a crossbar fabric does not scale linearly with the number of ports and for implementations with many ports a large chip area is consumed. Network switching nodes generally internally slice incoming packets into multiple of so-called flits of equal size. Such flits are then transported in fixed timeslots via a crossbar fabric to their destined output port, where they are reassembled to packets.

Keywords: Network on Chip (NOC), Resource Network Interface (NI), NOC SWITCHING TECHNIQUE, Circuit switching, Packet Switching, Store and Forward switching (SAF), Virtual Cut through Switching (VCT), Wormhole Switching (WH)

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Test and Fault Tolerance for Networks-on-Chip Infrastructures
Reza Kourdy and Mohammad Reza Nouri rad

The main concern for NoC/SoC test is the design of efficient test access mechanisms (TAMs) for delivering the test data to the individual cores under constraints such as test time, test power, and temperature. NoCs are built using a structured design approach, where a set of functional cores (processing elements, memory blocks, etc.) are interconnected through a data communication infrastructure that consists of switches and links. These cores can be organized either as regular or irregular topologies. Test of both routers and links must be integrated in a streamlined fashion. First, the already-tested NoC components can be used to transport the test data toward the components under test in a recursive manner. The inherent parallelism of the NoC structures allows propagating the test data simultaneously to multiple NoC elements under test. Test scheduling algorithms guarantee a minimal test time for arbitrary NoC topologies.

Keywords: Network on Chip (NOC), test access mechanism(TAM), deep submicron (DSM), Maximum Aggressor Fault (MAF).

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Network on Chip Switch-to-Switch Flow Control
Reza Kourdy and Mohammad Reza Nouri rad

NoC (Network on Chip) protocol family consist, switching techniques, routing protocols, and flow controls. These techniques are responsible for low-latency packet transfer. They strongly affect the performance, hardware amount, and power consumption of on-chip interconnection networks. Packet routing schemes decide routing paths between a given source and destination nodes. The channel buffer management technique does not let packets be discarded between two neighboring routers.

Keywords: Network on Chip (NOC), store-and-forward (SAF), wormhole(WH) switching, Virtual Cut-Through (VCT), asynchronous wormhole (AWH)

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Monitoring Services for Networks-on-Chips
Reza Kourdy and Mohammad Reza Nouri rad

Network monitoring is the process of extracting information regarding the operation of a network for purposes that range from management functions to debugging and diagnostics. Originally started in bus-based systems for the most basic and critical purpose of debugging, monitoring consisted of probes that could relay bus transactions to an external observer (be it a human or a circuit). The observability is crucial for debugging so that the behavior of the system is recorded and can be analyzed, either on- or off-line. When the behavior is recorded into a trace, the run-time evolution of the system can be replayed, facilitating the debugging process. Robustness in time or life-critical applications also requires monitoring of the system and real-time reaction upon false or misbehaving operation.

Keywords: Network on Chip (NOC), Monitoring, Verification and Debugging, NoC Monitoring

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Effect of slow start and Multiple packet drop of TCP Tahoe in Mesh NoC
Mohammad Reza Nouri Rad and Reza Kourdy

This paper shows the behavior of TCP Tahoe with Fast retransmission, slow start with multiple packet drop, and we show the effect of Slow start and Congestion avoidance algorithm for increase the reliability of network on chip (NoC).We simulate Mesh NoC architecture with Network Simulator 2 (NS2).

Keywords: Network-on-Chip, TCP Tahoe, multiple packet drop, slow start

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Effect of Different Round Trip Time of TCP Tahoe in Hexagon NoC
Mohammad Reza Nouri Rad and Reza Kourdy

This paper shows the behavior of TCP Tahoe with very different round trip (RTT) time in network on chip (NoC). The connection with a shortest RTT will get more packets sent and less packet loss compared to a connection with a longer RTT. We simulate Hexagon (6-gon) NoC architecture with Network Simulator 2 (NS2). The simulation results reveal the applicability of TCP Tahoe protocol in Congestion Control in proposed architecture.

Keywords: Network-on-Chip, TCP Tahoe

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Effect of Maximum Congestion Window with two Packet Drop of TCP Reno in Mesh NoC
Mohammad Reza Nouri Rad and Reza Kourdy

This paper shows the behavior of TCP Reno Fast recovery algorithm with two packet drop and maximum congestion window limitation for increase the performance of network on chip (NoC).We simulate Mesh NoC architecture with Network Simulator 2 (NS2). The simulation results reveal the applicability of TCP Tahoe protocol in Congestion Control in proposed architecture.

Keywords: Congestion Window, Network-on-Chip, TCP Reno

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Effect of Fast Recovery with Multiple packet drops of TCP Reno in Mesh NoC
Mohammad Reza Nouri Rad and Reza Kourdy

This paper shows the behavior of TCP Reno Fast recovery algorithm with multiple packet drops for increase the reliability of network on chip (NoC).We simulate Mesh NoC architecture with Network Simulator 2 (NS2). The simulation results reveal the applicability of TCP Reno protocol in Congestion Control in proposed architecture.

Keywords: Fast Recovery, Network-on-Chip, TCP Reno, Mesh NoC

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TCP Newreno Buffer Management in Network on Chip
Mohammad Reza Nouri Rad and Reza Kourdy

This paper was focused on study Transport Control Protocol (TCP) Newreno buffer management for increase performance of network on chip (NoC). We simulate Delay per acknowledgment (ACK) and one ACK for each packet for buffer management in Ring NoC architecture with Network Simulator 2 (NS2). The simulation results reveal the applicability of TCP Newreno in buffer management of NoC switches.

Keywords: Network-on-Chip, Buffer management, TCP Newreno

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Generalization of Blomer and May’s Attack for Arbitrary Public Exponent
R. Santosh Kumar, C.Narasimham, and S. Pallam Setty

In 2002, Blomer and May modified the attack of Boneh-Durfee low private exponent attack on RSA. Although they have achieved lower bound than Boneh and Durfee, their analysis is simple. In this paper, we follow their analysis to provide a bound for low private exponent whenever the public exponent is arbitrary sized.

Keywords: Lattices, Lattice reduction, RSA, Cryptanalysis

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Information Technology Security, Strategies and Practices in Higher Education: A Literature Review
Md. Waliullah, Jahidul Arafat, Golam Moktader Daiyan

Information security is a feverish issue due to drastic increasing application of computer, internet and internet user and intrusions. Various IT security approaches have been invented on this aspect while among them Balanced (composition of Technical and Non-technical security issues) IT Security approach (BITS) is highly lucrative now-a-days due to its simplicity and effectiveness in the sector of Information security especially in Higher education. Numerous researchers have performed their research work on this approach to triumph over its limitations for its sustainable and component implementation This paper has consolidated the useful consideration and proposal of various researchers to formulate a strong base of knowledge for the future researcher. It has also tined few unsettled issues of BITS approach which will open the casement of brainstorming as well as persuade them for future research on BITS approach, thereby allow BITS approach to attain a globally satisfactory shape for higher education information security.

Keywords: Information security, Hard Intervention, Soft intervention, balanced approach, Strategy, Practice

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New Energy Aware Routing to Prolong Network Operation Lifetime in Wireless Mesh Network
R.A.Sadeghzadeh, A.Saee Arezoomand, M.A.Pourmina, and N.Varjavand

Wireless Mesh Network (WMN) technology has recently become popular, chiefly for their self-configuring and low cost deployment in the areas of poor network infrastructure and terrain of difficult deployment. WMN includes the Internet Gateways (IGW), mesh routers and mesh clients forming three layer architectures. These mesh routers are minimal mobile and mesh clients are totally mobile which operate on batteries. Hence, power consumption becomes an important issue in mesh clients. In this paper we only consider the routing algorithm with limited battery energy of each mesh clients. To maximize the lifetime of mesh mobile networks, the power consumption rate of each node must be evenly distributed, it is essential to prolong each individual node (mobile) lifetime since the lack of mobile nodes can result in partitioning of the network, causing interruptions in communications between mobile nodes, and finally the overall transmission power for each connection request must be minimized. These two objectives cannot be satisfied simultaneously due to the NP hardness of the problem so a trade-off between these two conflict optimization objectives is needed. In this article we propose new energy consumption model, chiefly for the mesh clients to predict the lifetime of nodes according to current traffic conditions.

Keywords: Ad hoc Network; Energy Consumption; Power Control; Wireless Mesh

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