Vol 2 , No 1 (In publishing)





DOI: http://dx.doi.org/10.18063/wct.v2i1

Table of Contents

Original Research Articles

by Pierre-Richard Cornely
10 Views, 17 PDF Downloads

The antenna face of a phased array radar typically consists of several hundred of antenna elements, and they degrade independently.  This poses a challenging problem to radar target detection, discrimination, and classification, which rely on adaptive beamforming and assume that the channels are matched to each other.  In this research, a channel equalization algorithm is developed compensating for the mismatch between the reference and testing channels using the least-squares error (LSE) criterion. The equalized output is precisely the projection of the reference channel data onto the columns of the equalization matrix, which is solely a function of the testing channel output.  Through the analysis of the equalization matrix, the performance metrics including the squares error, instantaneous correlation coefficient, and cancellation ratio (CR) of the proposed equalizer are expressed in closed forms.  The analysis also allows us to postulate on the effect of system parameters including: window size, equalizer length, and input signal-to-noise ratio (SNR) on the performance metrics. Extensive Monte Carlo simulations show that higher values of the equalizer length, input SNR, or window size improves the CR; however, once a system parameter approaches a certain threshold, further incrementing the size of these parameters has a diminishing return on system performance.  Simulations also reveal that an equalizer with good CR or correlation coefficient results into the equalized testing channel output being almost a replica of the reference channel’s output. Correspondingly, degradation in the CR or correlation coefficient affects the equalized testing channel output.  The simulation results agree closely with known theoretical analyses. The research in this paper demonstrates the importance of channel equalization and system parameter selection in obtaining a satisfactory antenna elements/subarrays output.

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Original Research Articles

by Taha A. Elwi
25 Views, 11 PDF Downloads

The objective of this paper is to study intensively the design of a printed slotted patch based lotus shape structure mounted on a dielectric substrate backed with an electromagnetic band Gap (EBG) layer for wideband applications. The dielectric substrate is made of a Roger RT/duroid®5880 layer. An EBG layer is introduced on the back profile of the substrate to provide a high gain bandwidth product over wide frequency bands. The antenna is fed with a novel coplanar waveguide (CPW) structure of a flared geometry; therefore, the ground plane is mounted on the same substrate surface with the patch structure. A conductive trace is introduced at the substrate back from the bottom connected to the CPW through two shoring plates to remove the effects of the EBG layer on the feed structure. The EBG performance and the antenna design methodology are discussed using analytical analyses and numerical parametric studies, respectively. The numerical simulation is conducted using CST MWS Finally; the optimal antenna design is fabricated and measured for validation to be compared to the simulated results.

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Original Research Articles

by E. Sujatha Nil1, A. Chilambuchelvan 2
16 Views, 34 PDF Downloads

Biometric is emerging technology in identification and authentication of human being with more reliable and accurate. Combining multiple biometric systems is a promising solution to provide more security. It eliminates the disadvantages of unimodal biometric systems such as non-universality, noise in sensed data, intra-class variations, distinctiveness, spoof attacks and traditional method of authenticating a human and their identity. The proposed method depicts a multimodal biometric algorithm is designed to recognize individuals for robust and secured authentication using normalized score level fusion techniques with hybrid Genetic Algorithm and Particle Swarm Optimization for optimization in order to reduce False Acceptance Rate and False Rejection Rate and to enhance Equal Error Rate and Accuracy. 

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Original Research Articles

by Lokeswara Rao Bhogadi 1, N. Bhagyalaxmi 2
9 Views, 8 PDF Downloads

In the present era of information technology, there is a need to implement authentication and authorization techniques for security of resources. There are number of ways to prove authentication and authorization. But the biometric authentication beats all other techniques. Biometric techniques prove the authenticity or authorization of a human being based on his/her physiological or behavioural traits. Biometrics is a technique by which an individual's identity can be authenticated by applying the physical or behavioural trait. Physical traits like fingerprints, palm, iris etc. are based on the physical characteristics which are generally inherent and unique. Behavioural traits like voice, signature or keystroke dynamics etc. on the other hand, are quantifiable characteristics.They also protect access of resources from unauthorized users. Multimodal biometrics refers to the use of a combination of two or more biometric modalities in a verification / identification system. Identification based on multiple biometrics represents an emerging trend. The most compelling reason to combine different modalities is to improve the recognition rate. This can be done when biometric features of different biometrics are statistically independent. A multimodal biometric identification system aims to fuse two or more physical or behavioural traits. Multimodal biometric system is used in order to improve the accuracy. Multimodal biometric identification system based on iris, palm and fingerprint trait based on fusion logic is proposed. Typically in a multimodal biometric system, each biometric trait processes its information independently. The processed information is combined using curve let transform.

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Original Research Articles

by Anjali Verma 1, Raghavendra Pal 1, Arun Prakash 1, Rajeev Tripathi 1
9 Views, 13 PDF Downloads

Since traffic is increasing considerably day by day so information exchange for vehicular environment is very important to increase safety and to provide proper guidance of road side services available to driver during journey. Because of increased attraction towards Intelligent Transportation System (ITS) services it is required to design a system which can retrieve information very efficiently. A two-tier VANET/P2P system is basically the integration of two different type of services which are used for information exchange. Low-tier vehicular Ad-hoc networks (VANETs) can be used for achieving low lookup latency whereas high-tier infrastructure based Peer-to-Peer (P2P) can be used for increasing lookup success rate. In proposed protocol distance based reachability has been used. Reachability reduces lookup latency while maintaining moderate lookup success rate. Parameters for proposed adaptive lookup two-tier mechanism have been compared with the conventional two-tier lookup mechanism using Network Simulator (NS 2.34). 

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Original Research Articles

by Ahmed Elhattab 1, Nasim Uddin 2
16 Views, 26 PDF Downloads

Natural Frequencies of structures is an elegant intrinsic property that is essential for many Civil Structural applications, as Structural Health Monitoring and Simulation Modeling. The physically tangible relation between the frequency of the structures and its dynamic characteristics was the impetus for using different time/frequency based methods to quantify this fundamental property. Unfortunately, the disruption effect of noise requires incorporating advanced sensors, that provide signals with a low noise-intensity, to accurately identify the fundamental frequencies of the structure. This article solves this bottleneck via exploiting the Stochastic Resonance (SR) phenomena to extract the fundamental frequencies of a bridge using an acceleration recorded by a conventional portable sensor as the sensor implemented in small portable accelerometer. The portable accelerometer device has an M9 motion coprocessor designed mainly for tracking human activities. Human activities have an exaggerated amplitude when it is compared to the structural responses. Therefore, if an iPhone device is used to record the response of the structure (for example a bridge) the structure response will be swamped by severe surrounding noise because of its small amplitude. Therefore, in this vein, the SR phenomena has been employed to use rather than suppress the noise to magnify the feeble bridge response in the recorded acceleration and hence identify the corresponding frequency. The fidelity of the proposed approach has been verified using the data of a field experiment. The bridge frequencies are identified first using conventional vibration analysis, thereafter, the portable accelerometer has been attached to the bridge rail to record the bridge vibration under the passing traffic. The recorded data has been processed using a new Developed Underdamped Pinning Stochastic Resonance (DUPSR) technique to quantify the bridge frequency.

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