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Engineering and Technology (ICET), 2012 International Conference on

Date 10-11 Oct. 2012

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  • [Front cover]

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  • Welcome message

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  • Table of contents

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  • Program overview

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    Provides a schedule of conference events and a listing of which papers were presented in each session. View full abstract»

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  • Program details

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    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (421 KB)  

    Provides a schedule of conference events and a listing of which papers were presented in each session. View full abstract»

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  • Numerical study of the influence of mold filling conditions on the as-cast structure of Al-4 wt.% Cu ingots

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    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (541 KB) |  | HTML iconHTML  

    In the last few decades research efforts were conducted to grasp good understanding about the origin of equiaxed and columnar grains formed during solidification. The morphological evolutions such as globular/cellular to dendritic or columnar-to-equiaxed transition were generally studied. Correspondingly, some empirical models were introduced. Nevertheless, no sufficient attention was paid to incorporation of such models together with macroscopic phenomena. A 5-phase mixed columnar-equiaxed solidification model recently proposed by the current authors was used to predict the macrostructure formation. However previous results showed that the initial melt conditions can influence the predicted structure particularly at low pouring temperature. In the current work, the impact of mold filling conditions on the final solidification structure is numerically verified in two stages: during pouring using 3-phase globular-equiaxed model; and after filling using the 5-phase mixed columnar-equiaxed model. The calculated results are compared to the as-cast structures obtained from experiments. The results demonstrated the significance of the `big bang' nucleation and the `premature' solidification occurred during pouring at low melt superheat on the as-cast structure. View full abstract»

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  • Effect of the hydrostatic extrusion on the properties of extruded Al and Al/SiCp

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    This work is entitled to study the effect of hydrostatic extrusion, for different extrusion ratios on the mechanical properties of the extruded Al and Al/SiCP composites. An experimental hydrostatic extrusion device is designed and constructed for that purpose. Billets of Al and Al-SiCp composites with initial diameters of 15 and 20mm and with length of 50 mm are used. Reduction ratios of 43%, 55%, and 75% are performed. The mean extrusion pressure, tensile stress, microstructure and hardness of commercially pure aluminum extrudate are evaluated, as well as, for Al-SiC composites. Microstructure has significant changes after hydrostatic extrusion. The large grains with grain size 600 μm have refined after hydrostatic extrusion for pure Al, Fine precipitate in the direction of extrusion was recognize for Al/SiCP. It is also found that the extrusion improves the mechanical properties of pure Al and Al/SiCP in terms of the tensile strength and hardness. An apparent work hardening behavior was observed in the extrudate, the improvement of mechanical properties is mainly attributed to the fine grain strengthening effects. No cracks for Al/SiCP were observed after hydrostatic extrusion in comparison to conventional method, better surface quality was obtained. View full abstract»

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  • Fractional Fourier Transform OFDM system performance enhancement over doubly dispersive channels

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    The fractional Fourier transform (FrFT) has been suggested to improve the performance of the OFDM over doubly dispersive channels that cannot be achieved with traditional OFDM even with complex equalizers. In this paper the performance of OFDM based FrFT is studied with multiple fractional orders at different Doppler shift. Simulation results demonstrate processing improvement due to using FrFT instead of Fourier Transform (FT) in OFDM system. The same bit error rate (BER) is achieved without increasing the transmitting signal to noise ratio (SNR) and processing improvements are gained up to 3 dB for different Doppler frequencies. View full abstract»

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  • Blind adaptive signal reception for MC-CDMA systems in Rayleigh fading channels under multiple narrow-band interference signals

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    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1668 KB) |  | HTML iconHTML  

    This paper investigates the impact of multiple narrow-band interference (NBI) signals or jamming signals on the signal reception of multi-carrier code-division multiple-access (MC-CDMA) systems in single path Rayleigh fading channels. Different blind adaptive algorithms are proposed which determine a weight vector that optimally combines the desired signal contributions from different carriers while suppressing noise and interference. A performance comparison among these algorithms is provided via extensive simulations. No knowledge of the channel conditions (fading coefficients, signature sequences and timing of interferers, statistics of other noises, etc.) nor any training sequence is required. Performance results show that the proposed algorithms perform well and are robust against jamming or NBI. View full abstract»

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  • Performance analysis of DS-CDMA system using fast adaptive filtering under different jamming techniques

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    This paper proposes an enhancement to the performance of a Direct Sequence Code Division Multiple Access (DS-CDMA) system by utilizing an adaptive filter in the presence of different jamming techniques. In order to combat the impact of such jamming, the adaptive filter utilizes three adaptive algorithms which are the Variable Step-Size Affine Projection (VSS-APA) algorithm, the Generalized Normalized Gradient Descent (GNGD) algorithm, and the Generalized Square-Error-Regularized (GSER) NLMS algorithm. These algorithms have the advantages of fast convergence, low steady state mean squared error and the ability to improve the bit error rate (BER) performance of the conventional CDMA system, in the presence of multi-path, multiple-access, and different jamming signals. Results show that the VSS-APA outperforms other algorithms in the presence of barrage jamming. Whereas in the presence of partial band jamming the GSER-NLMS adaptive filter gives the best performance. View full abstract»

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  • Design considerations for piezoelectric energy harvesting systems

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    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (262 KB) |  | HTML iconHTML  

    Ultra low power microelectronic devices such as wireless sensor nodes can be self powered using piezoelectric energy harvesting systems. Piezoelectric energy harvesting is the technology to convert wasted vibration energy to an electrical energy output. This paper highlights the design considerations for piezoelectric energy harvesting (PEH) systems such as: material selection, resonant frequency, geometrical shape, loading factor, electrical connections, AC-DC converters, DC-DC converters, and energy storage media. Morphological analysis is developed to investigate the best alternative solution for each design parameter. The evaluation criterion is the maximum power transfer from input vibration energy to the electrical output waveform. The standards for PEH are also presented to enhance the system performance. The published results in the literature are discussed to affirm the concluding remarks in this paper. View full abstract»

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  • Authentication mechanisms in grid computing environment: Comparative study

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    For the reason that grid resources are valuable, access is usually limited, based on the requested resource and the requesting user's identity. Authentication in distributed systems like grid computing environment is the first defense line before other security aspects; authorization, confidentiality, integrity and auditing. The main grid authentication mechanisms challenges are single sign-on, secure credential repositories, and cross-domain authentication. This paper presents a comparative study of various authentication mechanisms in grid computing environment to investigate their pros and cons. Such analysis is particularly relevant for those seeking an intensive assessment to appropriate grid authentication mechanisms. View full abstract»

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  • High-resolution electric field sensor based on whispering gallery modes of a beam-coupled dielectric resonator

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    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (710 KB) |  | HTML iconHTML  

    This paper presents a high-resolution optical sensor concept for electric field detection. The sensing element is a coupled dielectric microsphere-beam. The material for both the sphere and the beam is polydimethylsiloxane (PDMS). The measurement principle is based on the whispering gallery optical mode (WGM) shifts of the microsphere. The external electric field imposes an electrtrostriction force on the dielectric beam, deflecting it. The beam, in turn compresses the sphere causing a shift in its WGM. An analysis is carried out along with preliminary experiments. Results show that electric fields as small as ~100 V/m can be detected using a 300 μm diameter sphere. View full abstract»

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  • HEARD: An automatic human EAR detection technique

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    A new class of biometrics based upon ear features was introduced for use in the development of passive identification. This paper presents an efficient technique for automatic ear detection from side face images. The proposed technique detects human's ear without any training or assumption of prior knowledge about the input image, and it does not need any human intervention so it can be used successfully in a fully automated ear recognition system. Two new features have been proposed for ear detection: the first represents elongation and is expressed by the ratio between the boundary's width and height. The second describes compactness and is measured by the ratio between the number of pixels composing the boundary's area and the number of pixels composing its perimeter. Each ratio should exceed a certain threshold for human's ear. Moreover, the proposed approach relies on the fact that the ear is a semi rounded boundary which contains other smaller semi rounded boundaries. The proposed technique uses the roundness as another feature. In human's ear, roundness falls within a certain range. Using these three features better detection performance is achieved and less time was needed. The experimental results demonstrate the effectiveness of the approach. View full abstract»

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  • Computer aided design and optimization of hypoid gears

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    Although hypoid gears provide smooth operation and high reduction ratios where compactness of design and maximum pinion strength are important, their efficiency is less than that of a similar set of spiral bevel gears. However, hypoid gears generally have greater tolerance to shock loading and can frequently be used at higher single stage ratios than spiral bevel gears. The objective of the present work is to develop a computer aided design (CAD) package for optimizing the design of hypoid gears. The CAD program calculates the gear set geometrical and strength performance variables such as the bending and contact safety factors. Strength calculations are based on ANSI/AGMA 2003-B97 standards. The CAD package allows the designer to select and change the design variables to satisfy any applied constraints. A genetic based optimization module manipulates the CAD package in a manner similar to the way that can be done by the designer but in an iterative and systematic way. The optimization module changes the design variables and compares the results to minimize the objective function subject to specified constraints. A minimum pinion volume objective function has been chosen in the present work. The main constraints are to equate the working bending and contact stresses to their respective allowable stresses. This would further make the best utilization of material and indirectly minimizes the volume. A numerical example is given to demonstrate the analysis procedure and the effectiveness of the optimization module. The results showed that the optimization procedure reduced the volume of a gear designed according to ANSI/AGMA 2003-B97 to 54% of its original volume. Further analysis was performed to study the effect of the design variables and the input parameters on the objective function. View full abstract»

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  • Human identification system based on feature level fusion using face and gait biometrics

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    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (265 KB) |  | HTML iconHTML  

    During the past years, face and gait recognition in video have received significant attention. Consequently, their recognition problems have challenged due to largely varying appearances and highly complex pattern distributions. However, the complementary properties of these two biometrics suggest fusion of them. Face recognition is more reliable when the person is close to the camera. On the other hand, gait is a suitable biometric trait for human recognition at a distance. Information from these two biometric sources, frontal of face and side of gait, are utilized and integrated at feature level. Face image is represented by the Active Lines among Face Landmark Points (ALFLP) feature vector. Gait image is represented by the Active Horizontal Levels (AHL) feature vector. Face and gait feature vectors are fused using a proposed effective fusion method. The proposed system was tested on CASIA database and the achieved results showed that the integrated face and gait features carry the most discriminating power compared to any individual biometric. View full abstract»

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  • Energy saving and reliable data reduction techniques for single and multi-modal WSNs

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    Wireless Sensor Networks (WSNs) suffer from many limitations such as the computing capabilities, and the allocated bandwidth. However, the limited energy source is the dominant factor where energy starvation occurs due to the large number of messages that need to be transferred through the network. In this paper, we propose new protocols to save the nodes energy as well as prolonging the overall network lifetime. Not like other protocols proposed in the literature, our protocols consider the accuracy/ reliability of the reported data to the sink node. Our first approach considers different types of wireless sensor networks including single and multimodal wireless sensor networks. Our second protocol utilizes the concept of distributed fuzzy logic agents for energy saving in wireless sensor network. Our approaches are extensively tested using simulation as well as real data captured from MIT WSN laboratory. In addition, the paper introduces a WSN prototype based on our data saving approaches. Our conclusion reveals promising results. View full abstract»

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  • Radiation detection based heterogeneous Wireless Sensor Network

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    Sensor deployment is one of the important problems in Wireless Sensor Network (WSN). Deployment affects the coverage of the network especially in critical applications such as in radiation detection. The contributions of this paper are 1) formulating the radiation detection deployment problem in a mathematical form where optimal solutions could be obtained, 2) utilizing one of the famous heuristic algorithms such as Genetic Algorithms (GA) for large scale deployment problems, 3) due to the importance of radiation detection, the paper focus on some of the characteristics of radiation detection problem including the subareas importance and the some of the sensors characteristics such as sensors' sensing and communication, etc. and 3) introducing a GA and Fuzzy logic as a hybrid solution to the problem in order to control the GA crossover and mutation percentages. Although, the concept of the hybrid algorithm is introduced in this paper for sensor deployment, it could be used to solve many other optimization problems. Through a large set of experiments with different problem settings, the efficiency of the proposed algorithms is verified. View full abstract»

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  • Manufacturing of ZTA composites for biomedical applications

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    Zirconia toughened alumina (ZTA) ceramics are interesting materials for biomedical applications due to their high strength, hardness, fracture toughness, abrasion resistance and excellent biocompatibility. The manufacturing of biomedical ceramic components involves the development of an integrated production process, beginning with the conditioning of the raw materials to the final component. Near-net-shape manufacturing technology is used to achieve a significant improvement in quality, production efficiency and cost. ZTA containing 10 vol-% zirconia (1.5Y) was produced from submicron size powders. The rheological behavior of 10 vol-% zirconia ZTA was investigated in order to optimize the recipes and predict the molding behavior. ZTA was in-situ reinforced with 5 vol-% strontium hexa-aluminate platelets with the intention to improve the mechanical properties. Results show that reinforcement of hexa-aluminate platelets enhance bending strength and fracture toughness but reduce the hardness of injection molded ZTA. View full abstract»

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  • On the lüder's strain of static strain aged dual phase steel

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    Dual-phase steel is characterized by an interesting combination of high strength, good ductility, continuous yielding, high initial work hardening rates, and a low yield stress to tensile strength ratio. The changes in the yield stress and appearance of prolonged lüder's strain in the stress strain curves of static strain aged dual phase steel motivate studying the parameters affecting the formation and width of the lüder's strain as function of aging conditions. Static strain aging of fine grained (5 μm) CMn-CrNb dual-phase (DP700) ferrite-martensite steel was investigated. A 3.2 mm sheet thickness of dual phase steel of martensite volume fraction of 0.306 was used to examine the aging behavior at the temperature range of 100 to 500°C for aging times 5 to 180 minutes. Quasi-static tensile tests and optical microstructure investigation were performed on the aged and the as-deformed dual phase steel. The stress strain curves were determined and analyzed to detect the condition of onset of the lüder's strain. A constant aging time of 30 minutes at different temperatures has showed the onset Lüder's strain to be at 190°C while, a 60 minutes aging at 170°C was needed for the onset of the Lüder's strain. The extent of Lüder's strain was observed to be time dependant for the various applied aging temperatures. Lüder's plateau was characterized by a serrated flow within the Lüder's strain and has been correlated to dynamic micro-mechanisms of hardening and softening. View full abstract»

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  • Characterization of mechanical and corrosion behavior of low-nickel cobalt-free maraging steel alloys

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    Three different samples of maraging steel alloys were characterized before and after aging process. Optical microscopy and SEM investigation have shown a clear precipitation as a result of the aging process. The EDX analysis supports the hypothesis of the formation of titanium and molybdenum rich precipitates at the grain boundaries after aging. The mechanical properties of the steel alloys were tested at room temperature as well as at elevated temperatures. High values of mechanical properties were obtained at room temperature. Nevertheless, the mechanical properties of the steel alloys dropped severely at elevated temperatures due to the austenite reversion phenomenon. This may also explain the high ductility in the material at elevated temperatures resulting in the high values of elongation which exceeded 50% in some samples and the significant drop in the values of the modulus of elasticity. The increase in the titanium mass percentage caused an increase in the value of hardness; however, it resulted in the embrittlement of the material and lowering the values of impact toughness. The corrosion behaviour of the alloys was tested in 3.5% NaCl. The solution treated samples have shown a more passive behavior than the aged samples did; however, the aging process has resulted in a significant enhancement of the corrosion resistances of the alloys. View full abstract»

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  • Secure clustering based SEP using Virtual ECC Group Key for Wireless Sensor Networks

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    A Wireless Sensor Network (WSN) is a collection of self-organized smart motes for achieving the desire of the assigned application. However, for the different limitations facing these motes including memory available, computational and communicational limitations, clustering them is one of the main solutions for prolonging the lifetime of the network. At the same time, due to the critical information transferred through the network, security is considered as main challenge for WSNs. This paper proposes a new security framework called Virtual ECC Group Key (VEGK) merging Elliptic Curve Cryptography (ECC) with symmetric pairwise keys. In addition, we believe that merging security with clustering will be beneficial to the energy saving in WSN, this paper is based on Stable Election Protocol (SEP) based clustering. Based on the analysis of different scenarios, our proposed security framework is proved to protect the network from many attacks. View full abstract»

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  • Entropy based video watermarking scheme using wavelet transform and Principle Component Analysis

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    In this paper, a comprehensive approach for digital video watermarking is introduced, where a binary watermark image is embedded into the video frames. Each video frame is decomposed into sub-images using 3 level discrete wavelet transform then the Principle Component Analysis (PCA) transformation is applied for some selected blocks. The selection of the blocks depends on calculating the entropy of each block then the maximum entropy blocks were selected. The watermark is embedded into the maximum coefficient of the PCA block. The proposed scheme is tested using a number of video sequences. Experimental results show high imperceptibility and high robustness against several attacks. The computed PSNR achieves high score which is 47.1078 db. View full abstract»

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  • Effect of strain relaxation on the drain conductance in AlGaN/GaN HEMTs

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    The aim of this work is to study the potential offered by microwave power in the device AlmGa1-mN/GaN HEMT. The effects of technological and electrical parameters such as the aluminum mole fraction "m", the thickness of the AlGaN doped layer "dd" and doping concentration "Nd" in the output conductance are studied taking into account the effects of spontaneous and piezoelectric polarizations in the heterojunction AlGaN/GaN and the relaxation of the crystal lattice induced by the aluminum mole fraction. We presented an analytical model for the electrons concentration "ns" in the 2DEG and the current Ids in the channel for strong inversion regime by solving the Poisson equation and Schrödinger self-consistent calculations. From the analytical model of the current Ids including the effects of spontaneous and piezoelectric polarizations, and lattice relaxation, the output conductance gds according to the voltage Vds are deduced. We note that, the increasing of "m" and "Nd" increase the carrier density "ns" in the 2DEG. Although, the increase of the doped layer thickness increases the output conductance. The influence of the crystal lattice relaxation on the electrical performance acts directly on the threshold voltage if the value of the mole fraction exceeds 0.38. View full abstract»

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  • Biometric image protection based on discrete cosine transform watermarking technique

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    This paper presents combined face recognition and watermarking technique to secure a biometric image and maintain the recognition rate. These days, with advanced technology, the biometric data can be stolen and faked which may be used in other applications that utilize the same biometric feature. The discrete cosine transform (DCT) watermarking technique is used to certify the biometric image belong to the legitimate user. We have tested the proposed scheme under several attacks. The results of the experimentations show that the face recognition rate performance almost does not degrade due to watermark embedding and the proposed scheme is robust against several attacks. View full abstract»

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