July 2010, No. 3
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Spiral Bit-string Representation of Color
for Image Retrieval

Abdelhamid Abdesselam1, Hui Hui Wang2, and Narayanan Kulathuramaiyer2
1Department of Computer Science, Sultan Qaboos University, Oman
2Faculty of Computer Science and Information Technology, UNIMAS, Malaysia

Abstract: This paper describes a color-based image retrieval technique that uses a new representation for the color content of an image. The new representation, called Spiral Bit-string Representation, is an extension of the traditional bitmap signature representation, where the image description is performed in a spiral manner, starting from the centre of the image and moving clockwise towards the border. The major advantages of this representation are its simplicity, its suitability for retrieval of rotated and scaled images as well as for sub-image querying.

Keywords: Color Image Retrieval, bit-string representation, rotation-invariant, scale-invariant.

Received June 10, 2008; accepted September 2, 2008


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Chaos-Based Key Stream Generator
Based on Multiple Maps Combinations and its Application to Images Encryption

         Kamel Faraoun
Département d’informatique, UDL University, Algeria

Abstract: : In recent years, growing number of cryptosystems based on chaos have been proposed. However, most of them encounter some problems such as: low level of security and small key space. The key stream generator is the key design issue of an encryption system. It directly determines security and efficiency, but most of the proposed key streams are binary valued, and suffer from short period and limited key space. In this paper, we propose an n-ary key stream generator, based on hierarchical combination of three chaotic maps. We demonstrate that the produced key streams have good statistical properties, such as uniform distribution, δ-like auto-correlation function, near-zero cross-correlation and very height sensitivity to initial conditions, under precision restricted condition. An image cryptosystem is constructed using the proposed approach and proven to be enough secure to resist various attacks. Complexity is analysed and an effective acceleration of chaos-based image cryptosystems is shown to be achievable.

Keywords: Chaotic maps, images cryptography, key stream generation, security.

Received December 1, 2008; accepted January 27, 2009

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Mining Multiple Large Data Sources

Animesh Adhikari1, Pralhad Ramachandrarao2, Bhanu Prasad3, and Jhimli Adhikari4
1Department of Computer Science, S. P. Chowgule College, India
2Department of Computer Science and Technology, Goa University, India
3Department of Computer and Information Sciences, Florida A&M University, USA
4Department of Computer Science, Narayan Zantye College, India

Abstract: Effective data analysis using multiple databases requires highly accurate patterns. Local pattern analysis might extract low quality patterns from multiple large databases. Thus, it is necessary to improve mining multiple databases using local pattern analysis. We present existing specialized as well as generalized techniques for mining multiple large databases. We formalize the idea of multi-database mining using local pattern analysis and propose a new generalized technique for mining multiple large databases. It improves the quality of synthesized global patterns significantly. We conduct experiments on both real and synthetic databases to judge the effectiveness of the proposed technique.

Keywords: Multi-database mining, pipelined feedback technique, synthesis of patterns.

Received December 21, 2008; accepted February 8, 2009

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Synthesis of Multibeam Antennas Arrays with a Modified Particle Swarm Optimization Algorithm

Hichem Chaker, Sidi Mohamed Meriah, and Fethi Tarik Bendimerad
Faculty of Engineering, Tlemcen University, Algeria

Abstract: In this paper, we intend to study the synthesis of the multibeam arrays. The synthesis implementation’s method for this type of arrays permits to approach the appropriated radiance’s diagram. An adaptive particle swarm optimization algorithm (APSO) is proposed to synthesis multibeam antenna arrays.  The problem is formulated and solved by means of the proposed algorithm. The examples are simulated to demonstrate the effectiveness and the design flexibility of adaptive PSO in the framework of electromagnetic synthesis of linear arrays.

Keywords: Multibeam, optimization, adaptive particle swarm optimization, synthesis, linear antenna arrays.

Received June 24, 2008; accepted  February 16, 2009

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Uplink Downlink Limited Round Robin
Scheduling Algorithms

Rawya Rizk
Electrical Engineering Department, Suez Canal University, Egypt

Abstract: Several polling algorithms have been proposed to overcome the slot wastage problem due to the exchange of POLL or NULL packets in the case of no data to transmit. However, most of these algorithms suffer from achieving the fairness among all slaves. This paper proposes two scheduling algorithms, Uplink Downlink Limited Round Robin (LRR) with fixed cycle time and Uplink Downlink LRR with adaptive cycle time. They utilize the status of the uplink queues in addition to the downlink queues to schedule the slots effectively. The proposed algorithms combine the simplicity and fairness of the LRR algorithm with the efficiency of the queue state dependent packet algorithms. Simulation results show that the proposed scheduling algorithms achieve higher utilization, lower delay and reasonable fairness among the slaves compared to the existed LRR algorithm. These results are proved practically. Experimental results confirm that, the proposed algorithms achieve more than 14% improvement in the utilization compared to the LRR algorithm in asymmetric traffic conditions.

Keywords: Bluetooth, intra piconet scheduling algorithms, polling, Round Robin, segmentation and reassembly.

Received July 20, 2008; accepted November 31, 2008

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3D Model Retrieval Based on 3D
Discrete Cosine Transform

Elmustapha Ait Lmaati, Ahmed El Oirrak, Mohamaed Najib Kaddioui, Abdellah Ait Ouahman, and Mohammed Sadgal  
Department of Computer Science, Cadi Ayyad University, Morocco

Abstract: The content-based retrieval systems for 3D models on the Web become necessary since digital databases of 3D objects are growing. In this paper, we propose a new method to describe 3D models. This method is based on 3D discrete cosine transform  which is applied for the voxelized 3D model. The discrete cosine transform is widely used for 2D image compression and it shows its performance for the JPEG compression algorithm. The proposed descriptor is implemented in our 3D search engine, tested using the princeton shape benchmark database, tested for noise and decimation; and compared to other 3D descriptors known in the literature.

Keywords: Search engine, 3D models, retrieval systems, 3D discrete cosine transform.

Received October 3, 2008; accepted January 27, 2009


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Improving Fuzzy Algorithms for Automatic Magnetic Resonance Image Segmentation

Elnomery  Zanaty and Sultan Aljahdali
College of Computer Science, Taif University, Saudi Arabia

Abstract: In this paper, we present reliable algorithms for fuzzy k-means and C-means that could improve MRI segmentation. Since the k-means or FCM method aims to minimize the sum of squared distances from all points to their cluster centers, this should result in compact clusters. Therefore the distance of the points from their cluster centre is used to determine whether the clusters are compact. For this purpose, we use the intra-cluster distance measure, which is simply the median distance between a point and its cluster centre. The intra-cluster is used to give us the ideal number of clusters automatically; i.e a centre of the first cluster is used to estimate the second cluster, while an intra-cluster of the second cluster is obtained. Similar, the third cluster is estimated based on the second cluster information (centre and intra cluster), so on, and only stop when the intra-cluster is smaller than a prescribe value. The proposed algorithms are evaluated and compared with established fuzzy k-means and C-means methods by applying them on simulated volumetric MRI and real MRI data to prove their efficiency. These evaluations, which are not easy to specify in the absence of any prior knowledge about resulted clusters, for real MRI dataset are judged visually by specialists since a real MRI dataset cannot give us a quantitative measure about how much they are successful.

Keywords:Machine learning, medical imaging, fuzzy clustering, image segmentation, clustering validation.

Received April 12,  2008; accepted February 8, 2009

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Innovative Algorithms for the Header
Processing Transition from IPv4 to IPv6
and Vice Versa

Basil Al-Kasasbeh1, Rafa Al-Qutaish2, and Mohammad Muhairat2
 1Faculty of Information Technology, Applied Science University, Jordan
2Department of Software Engineering, Alzaytoonah University of Jordan, Jordan

Abstract: The huge numbers of computers, devices and networks that connected to the Internet in the networking industry, that require more address space, better Quality of Services support, greater security, and an increasing number of media types and Internet-capable devices have all contributed to drive the development of new IPv6 protocol. The major importance during the development of IPv6 has been how to do the transition away from IPv4 towards IPv6 and vice versa. The work on transition strategies, tools, and mechanisms has been part of the basic IPv6 design effort from the beginning. The transition process from the current IPv4 to the future IPv6 is probably one of the most important subjects during the next generation protocols. This paper reviews the basics of IPv4 and IPv6 headers, and the methods for managing the transformation between IPv4 and IPv6. The proposed algorithms deal with header processing transformation transition between IPv4/IPv6 and vice versa depending on the bi-directional identification and recognition processes of the two distinct headers. 

Keywords: IPv4/IPv6 transition, IPv4/IPv6 header processing, IP tunneling, IP encapsulation, address mapping, dual stack.

Received November 9, 2008; accepted April 14, 2009

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Development of Neural Networks for Noise Reduction

Lubna Badri
Faculty of Engineering, Philadelphia University, Jordan

Abstract: This paper describes the development of neural network models for noise reduction. The networks used to enhance the performance of modeling captured signals by reducing the effect of noise. Both recurrent and multi-layer Backpropagation neural networks models are examined and compared with different training algorithms. The paper presented is  to illustrate the effect of training algorithms and  network architecture on neural network performance for a given application.

Keywords: Noise reduction, recurrent neural networks, multi-layer backpropagation.

Received January 3, 2009; accepted February 25, 2009

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Mediation Queries Adaptation After the
Removal of a Data Source

Latifa Baba-Hamed
 Computer Science Department, University of Oran Es-sénia, Algeria

Abstract: A broad variety of data is available in distinct heterogeneous sources, stored under different formats: database formats (in relational and object-oriented models), document formats (SGML/XML), browser formats (HTML), message formats, etc. The integration of such data is increasingly important for modern information systems applications such as data warehousing, data mining, and web applications. This is realized by providing a uniform view of data sources  (called mediation schema or global schema) and defining a set of queries (called mediation queries or mediation mappings) which define objects of the mediation schema. One of the important problems that merit consideration is the impact of schema evolution on mediation queries. Mappings left inconsistent by a schema change have to be detected and updated. In particular, one source may be removed from the system because it provides always obsolete information or because it is unavailable. In this case it is necessary to update the inconsistent mappings. In this paper, we study the removal of a source from an integration system and show how to correctly update the mappings between the mediation schema and the distributed sources after this change, in the context of the global-as-view  approach (each relation of the global schema is expressed as a view on the data source).

Keywords: Mediation system, schema evolution, mediation queries, relevant relation, operation graph.

Received November 8, 2008; accepted May 17, 2009

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Prolonging Network Lifetime and Data Accumulation in Heterogeneous Sensor Networks

Dilip Kumar1, Trilok Chand Aseri2, and Ram Bahadur Patel3
1Centre for Development of Advanced Computing, Ministry of Communication & IT, India
PEC University of Technology, India
3Department of Computer Science and Engineering, Maharishi Markandeshwar University, India

Abstract: Research on Wireless Sensor Networks has often assumed homogeneous nodes. In reality, homogeneous nodes have different capabilities like different levels of initial energy and drain rate. This leads to the research on heterogeneous networks where two or more types of nodes are considered within the network and the more powerful sensor nodes act as cluster heads. In this paper, we have analyzed a heterogeneous network with three types of nodes having different initial energy levels.  A single hop clustering topology has been assumed and analyzed the network performance in terms of lifetime. Simulation results show that the network lifetime is much better in proposed protocol than the existing protocols.

Keywords: Wireless sensor networks, heterogeneous, lifetime, clustering.

Received November 11, 2008; accepted May 17, 2009


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Multiple Warehouses Scheduling Using
Steady State Genetic Algorithms

Jalal Atoum1 and Mamoun Al Rababaa2
1Computer Science Department, Princess Symaya University for Technology, Jordan
2Computer Science Department, Al Al-Bayt University, Jordan

Abstract: Warehouses scheduling is the problem of sequencing requests of products to fulfill several customers’ orders so as to minimize the average time and shipping costs. In this paper, a solution to the problem of multiple warehouses scheduling using the steady state genetic algorithm is presented. A mathematical model that organizes the relationships between customers and warehouses is also presented in this paper. Two scenarios of storage capacities (constants and varying capacities) and two strategies of search points (ideal point and random points) are compared. An analysis of the results indicates that  multiple warehouses scheduling using the GENITOR approach with different warehouses capacities have better outcome than the usage of the traditional genetic algorithms).

Keywords: Multiple warehouse scheduling, genitor, ideal point search strategy, random point search strategy.

Received October 27, 2008; accepted May 17, 2009

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Realization of a Novel Fault Tolerant Reversible Full Adder Circuit in Nanotechnology

Saiful Islam, Muhammad Mahbubur Rahman, Zerina Begum, and Mohd Zulfiquar Hafiz
 Institute of Information Technology, University of Dhaka, Bangladesh

Abstract:In parity preserving reversible circuit, the parity of the input vector must match the parity of the output vector. It renders a wide class of circuit faults readily detectable at the circuit’s outputs. Thus reversible logic circuits that are parity preserving will be beneficial to the development of fault tolerant systems in nanotechnology. This paper presents an efficient realization of well known Toffoli gate using only two parity preserving reversible gates. The minimum number of garbage outputs and constant inputs required to synthesize a fault tolerant reversible full adder circuit has also been given. Finally, this paper presents a novel fault tolerant reversible full adder circuit and demonstrates its superiority with the existing counterparts.

Keywords: Reversible logic, reversible gate, parity preserving reversible gates, conservative reversible gate, and reversible full adder circuit.

Received September 10, 2008; accepted May 17, 2009

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Improving the Effectiveness of the
Color Coherence Vector

Alaa Al-Hamami1 and Hisham Al-Rashdan2
1Computer Science Department, Amman Arab University for Graduate Studies, Jordan
2Computer Science, Yarmouk University, Jordan

Abstract: This paper was motivated by the desire to improve the effectiveness of retrieving images on the basis of their color content by improving the Color Coherence Vector method. There is a growing demand for efficient and effective image retrieving techniques from the huge multimedia databases on the Internet and from the image libraries. In this paper three methods have been proposed and developed to improve the effectiveness of the Color Coherence Vector  method: The modified Color Coherence Vector based on the number of the color coherence regions, The modified Color Coherence Vector based on the distance of the color coherence regions and The modified Color Coherence Vector based on the angle of the color coherence regions. The proposed methods take advantage of the coherence regions number and location information. The information of the coherence regions number, distance and angle along with the coherence and incoherence pixels amount for each color was presented by using the simple and flexible histogram representation technique. The experiments were carried out on a collection of 1014 color images of which 100 query images were used as stimuli for retrieving similar images from the image collection. The experimental results indicate that the three proposed methods perform better than Color Coherence Vector  in terms of retrieval effectiveness; the developed methods produce better recall-precision curves and produce better ordering values in terms of Eavg (Ratio (average-rank to ideal-average-rank)). These results provide evidence for the importance of the coherence regions number and location information which have been neglected by the original method color coherence vector.

Keywords: Content-based image retrieval, color coherence vector, color-based image retrieval, and color indexing.

Received April 12, 2008; accepted February 8, 2009

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Complex Gain Predistortion in WCDMA Power Amplifiers with Memory Effects

Pooria Varahram, Somayeh Mohammady, Mohd Nizar Hamidon, Roslina Mohd Sidek,
and Sabira Khatun
 Department of Electronics and Electrical Engineering, University Putra Malaysia, Malaysia

Abstract: IPower amplifiers are essential components in communication systems and are inherently nonlinear. The nonlinearity creates spectral growth beyond the signal bandwidth, which interferes with adjacent channels. It also causes distortions within the signal bandwidth, which decreases the bit error rate at the receiver. In digital predistortion system, an inverse characteristic of power amplifier is generated and its amplitude and phase are combined to the signal input. So the input signal is predistorted and the power amplifier response is corrected. This process has to be controlled at high accuracy to achieve a satisfactory compensation effect. The inverse characteristics are stored in a memory (look-up table) and this data are updated using an error that is produced by comparing the outputs of power amplifier with the input signals. In this paper a novel technique for compensating such effects is proposed. It is a combination of two techniques, memory polynomial predistortion and the gain based predistorter method. This method is compared with the other technique, memory polynomial method and validated using a 1.9 GHz 60W LDMOS power amplifier and various signals such as 2-carrier WCDMA with 10 MHz carrier spacing and 15 MHz bandwidth. Simulations and results show improvement in ACLR reduction and EVM with applying this method.

Keywords: Digital predistortion, memory effects, ACLR, power amplifier, WCDMA.

Received November 16, 2008; accepted  May 17, 2009

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