Showing papers in "World Academy of Science, Engineering and Technology, International Journal of Electrical, Computer, Energetic, Electronic and Communication Engineering in 2010"

Denial of Service (DOS) Attack and Its Possible Solutions in VANET

Abstract: Vehicular Ad-hoc Network (VANET) is taking more attention in automotive industry due to the safety concern of human lives on roads. Security is one of the safety aspects in VANET. To be secure, network availability must be obtained at all times since availability of the network is critically need ed when a node sends any life critical information to other nodes. However, it can be expected that security attacks are likely to increase in the coming future due to more and more wireless applications being developed and deployed onto the well-known expose nature of the wireless medium. In this respect, the network availability is exposed to many types of attacks. In this paper, Denial of Service (DOS) attack on network availability is presented and its severity level in VANET environment is elaborated. A model to secure the VANET from the DOS attacks has been developed and some possible solutions to overcome the attacks have been discussed.

Computing Fractal Dimension of Signals using Multiresolution Box-counting Method

Abstract: In this paper, we have developed a method to compute fractal dimension (FD) of discrete time signals, in the time domain, by modifying the box-counting method. The size of the box is dependent on the sampling frequency of the signal. The number of boxes required to completely cover the signal are obtained at multiple time resolutions. The time resolutions are made coarse by decimating the signal. The loglog plot of total number of boxes required to cover the curve versus size of the box used appears to be a straight line, whose slope is taken as an estimate of FD of the signal. The results are provided to demonstrate the performance of the proposed method using parametric fractal signals. The estimation accuracy of the method is compared with that of Katz, Sevcik, and Higuchi methods. In ddition, some properties of the FD are discussed.

A 1.2-ns16×16-Bit Binary Multiplier Using High Speed Compressors

Abstract: � Abstract—For higher order multiplications, a huge number of adders or compressors are to be used to perform the partial product addition. We have reduced the number of adders by introducing special kind of adders that are capable to add five/six/seven bits per decade. These adders are called compressors. Binary counter property has been merged with the compressor property to develop high order compressors. Uses of these compressors permit the reduction of the vertical critical paths. A 16×16 bit multiplier has been developed using these compressors. These compressors make the multipliers faster as compared to the conventional design that have been used 4-2 compressors and 3-2 compressors. Keywords—Binary multiplier, Compressors, Counter, Column adder, Low power.

Design of High-speed Modified Booth Multipliers Operating at GHz Ranges

Abstract: This paper describes the pipeline architecture of high-speed modified Booth multipliers. The proposed multiplier circuits are based on the modified Booth algorithm and the pipeline technique which are the most widely used to accelerate the multiplication speed. In order to implement the optimally pipelined multipliers, many kinds of experiments have been conducted. The speed of the multipliers is greatly improved by properly deciding the number of pipeline stages and the positions for the pipeline registers to be inserted. We described the proposed modified Booth multiplier circuits in Verilog HDL and synthesized the gate-level circuits using 0.13um standard cell library. The resultant multiplier circuits show better performance than others. Since the proposed multipliers operate at GHz ranges, they can be used in the systems requiring very high performance. Keywords—multiplier, pipeline, high-speed, modified Booth algorithm.

Error Correction Codes in Wireless Sensor Network: An Energy Aware Approach

Abstract: Link reliability and transmitted power are two important design constraints in wireless network design. Error control coding (ECC) is a classic approach used to increase link reliability and to lower the required transmitted power. It provides coding gain, resulting in transmitter energy savings at the cost of added decoder power consumption. But the choice of ECC is very critical in the case of wireless sensor network (WSN). Since the WSNs are energy constraint in nature, both the BER and power consumption has to be taken into count. This paper develops a step by step approach in finding suitable error control codes for WSNs. Several simulations are taken considering different error control codes and the result shows that the RS(31,21) fits both in BER and power consumption criteria. Keywords—Error correcting code, RS, BCH, wireless sensor networks

A Survey on Voice over IP over Wireless LANs

Abstract: Voice over Internet Protocol (VoIP) is a form of voice communication that uses audio data to transmit voice signals to the end user. VoIP is one of the most important technologies in the World of communication. Around, 20 years of research on VoIP, some problems of VoIP are still remaining. During the past decade and with growing of wireless technologies, we have seen that many papers turn their concentration from Wired-LAN to Wireless-LAN. VoIP over Wireless LAN (WLAN) faces many challenges due to the loose nature of wireless network. Issues like providing Quality of Service (QoS) at a good level, dedicating capacity for calls and having secure calls is more difficult rather than wired LAN. Therefore VoIP over WLAN (VoWLAN) remains a challenging research topic. In this paper we consolidate and address major VoWLAN issues. This research is helpful for those researchers wants to do research in Voice over IP technology over WLAN network. Keywords—Capacity, QoS, Security, VoIP Issues, WLAN.

Capacitor Placement in Radial Distribution System for Loss Reduction Using Artificial Bee Colony Algorithm

Abstract: This paper presents a new method which applies an artificial bee colony algorithm (ABC) for capacitor placement in distribution systems with an objective of improving the voltage profile and reduction of power loss. The ABC algorithm is a new population based meta heuristic approach inspired by intelligent foraging behavior of honeybee swarm. The advantage of ABC algorithm is that it does not require external parameters such as cross over rate and mutation rate as in case of genetic algorithm and differential evolution and it is hard to determine these parameters in prior. The other advantage is that the global search ability in the algorithm is implemented by introducing neighborhood source production mechanism which is a similar to mutation process. To demonstrate the validity of the proposed algorithm, computer simulations are carried out on 69-bus system and compared the results with the other approach available in the literature. The proposed method has outperformed the other methods in terms of the quality of solution and computational efficiency. Keywords—Distribution system, Capacitor Placement, Loss reduction, Artificial Bee Colony Algorithm.

Neural Network Optimal Power Flow(NN-OPF) based on IPSO with Developed Load Cluster Method

Abstract: An Optimal Power Flow based on Improved Particle Swarm Optimization (OPF-IPSO) with Generator Capability Curve Constraint is used by NN-OPF as a reference to get pattern of generator scheduling. There are three stages in Designing NN-OPF. The first stage is design of OPF-IPSO with generator capability curve constraint. The second stage is clustering load to specific range and calculating its index. The third stage is training NN-OPF using constructive back propagation method. In training process total load and load index used as input, and pattern of generator scheduling used as output. Data used in this paper is power system of Java-Bali. Software used in this simulation is MATLAB. Keywords—Optimal Power Flow, Generator Capability Curve, Improved Particle Swarm Optimization, Neural Network

Optimal DG Allocation in Distribution Network

Abstract: This paper shows the results obtained in the analysis of the impact of distributed generation (DG) on distribution losses and presents a new algorithm to the optimal allocation of distributed generation resources in distribution networks. The optimization is based on a Hybrid Genetic Algorithm and Particle Swarm Optimization (HGAPSO) aiming to optimal DG allocation in distribution network. Through this algorithm a significant improvement in the optimization goal is achieved. With a numerical example the superiority of the proposed algorithm is demonstrated in comparison with the simple genetic algorithm. Keywords--Distributed Generation, Distribution Networks, Genetic Algorithm, Particle Swarm Optimization.

Performance Comparison of Single and Multi-Path Routing Protocol in MANET with Selfish Behaviors

Abstract: Mobile Ad Hoc network is an infrastructure less network which operates with the coordination of each node. Each node believes to help another node, by forwarding its data to/from another node. Unlike a wired network, nodes in an ad hoc network are resource (i.e. battery, bandwidth computational capability and so on) constrained. Such dependability of one node to another and limited resources of nodes can result in non cooperation by any node to accumulate its resources. Such non cooperation is known as selfish behavior. This paper discusses the performance analysis of very well known MANET single-path (i.e. AODV) and multi-path (i.e. AOMDV) routing protocol, in the presence of selfish behaviors. Along with existing selfish behaviors, a new variation is also studied. Extensive simulations were carried out using ns-2 and the study concluded that the multi-path protocol (i.e. AOMDV) with link disjoint configuration outperforms the other two configurations. Keywords—performance analysis, single and multi path protocol, selfish behaviors.

Effect of Derating Factors on Photovoltaics under Climatic Conditions of Istanbul

Abstract: As known that efficiency of photovoltaic cells is not high as desired level. Efficiency of PVs could be improved by selecting convenient locations that have high solar irradiation, sunshine duration, mild temperature, low level air pollution and dust concentration. Additionally, some environmental parameters called derating factors effect to decrease PV efficiencies such as cloud, high temperature, aerosol optical depth, high dust concentration, shadow, snow, humidity etc. In this paper, all parameters that effect PV efficiency are considered in detail under climatic conditions of Istanbul. A 750 Wp PV system with measurement devices is constructed in Maslak campus of Istanbul Technical University. Keywords—Efficiency, Derating Factor, Istanbul, Photovoltaic.

Color Image Segmentation using Adaptive Spatial Gaussian Mixture Model

Abstract: An adaptive spatial Gaussian mixture model is proposed for clustering based color image segmentation A new clustering objective function which incorporates the spatial information is introduced in the Bayesian framework The weighting parameter for controlling the importance of spatial information is made adaptive to the image content to augment the smoothness towards piecewisehomogeneous region and diminish the edge-blurring effect and hence the name adaptive spatial finite mixture model The proposed approach is compared with the spatially variant finite mixture model for pixel labeling The experimental results with synthetic and Berkeley dataset demonstrate that the proposed method is effective in improving the segmentation and it can be employed in different practical image content understanding applications Keywords—Adaptive; Spatial; Mixture model; Segmentation ; Color

Identifications and Monitoring of Power System Dynamics Based on the PMUs and Wavelet Technique

Abstract: Low frequency power oscillations may be triggered by many events in the system. Most oscillations are damped by the system, but undamped oscillations can lead to system collapse. Oscillations develop as a result of rotor acceleration/deceleration following a change in active power transfer from a generator. Like the operations limits, the monitoring of power system oscillating modes is a relevant aspect of power system operation and control. Unprevented low-frequency power swings can be cause of cascading outages that can rapidly extend effect on wide region. On this regard, a Wide Area Monitoring, Protection and Control Systems (WAMPCS) help in detecting such phenomena and assess power system dynamics security. The monitoring of power system electromechanical oscillations is very important in the frame of modern power system management and control. In first part, this paper compares the different technique for identification of power system oscillations. Second part analyzes possible identification some power system dynamics behaviors Using Wide Area Monitoring Systems (WAMS) based on Phasor Measurement Units (PMUs) and wavelet technique. Keywords—Power system oscillations, Modal analysis, Prony, Wavelet, PMU, Wide Area Monitoring System.

Noise Performance of Millimeter-wave Silicon Based Mixed Tunneling Avalanche Transit Time(MITATT) Diode

Abstract: A generalized method for small-signal simulation of avalanche noise in Mixed Tunneling Avalanche Transit Time (MITATT) device is presented in this paper where the effect of series resistance is taken into account. The method is applied to a millimeter-wave Double Drift Region (DDR) MITATT device based on Silicon to obtain noise spectral density and noise measure as a function of frequency for different values of series resistance. It is found that noise measure of the device at the operating frequency (122 GHz) with input power density of 10 Watt/m is about 35 dB for hypothetical parasitic series resistance of zero ohm (estimated junction temperature = 500 K). Results show that the noise measure increases as the value of parasitic resistance increases. Keywords—Noise Analysis, Silicon MITATT, Admittance characteristics, Noise spectral density.

An Effective Method of Head Lamp and Tail Lamp Recognition for Night Time Vehicle Detection

Abstract: This paper presents an effective method for detecting vehicles in front of the camera-assisted car during nighttime driving. The proposed method detects vehicles based on detecting vehicle headlights and taillights using techniques of image segmentation and clustering. First, to effectively extract spotlight of interest, a segmentation process based on automatic multi-level threshold method is applied on the road-scene images. Second, to spatial clustering vehicle of detecting lamps, a grouping process based on light tracking and locating vehicle lighting patterns. For simulation, we are implemented through Da-vinci 7437 DSP board with near infrared mono-camera and tested it in the urban and rural roads. Through the test, classification performances are above 97% of true positive rate evaluated on real-time environment. Our method also has good performance in the case of clear, fog and rain weather. Keywords—Assistance Driving System, Multi-level Threshold Method, Near Infrared Mono Camera, Nighttime Vehicle Detection.

Fault Detection of Broken Rotor Bars Using Stator Current Spectrum for the Direct Torque Control Induction Motor

Abstract: The numerous qualities of squirrel cage induction machines enhance their use in industry. However, va rious faults can occur, such as stator short-circuits and rotor fail ures. In this paper, we use a technique based on the spec tral analysis of stator current in order to detect the fault in the machine: broken rotor bars. Thus, the number effect of the breaks has bee n highlighted. The effect is highlighted by considering the machine co ntr lled by the Direct Torque Control (DTC). The key to fault detec tion is the development of a simplified dynamic model of a squi rrel cage induction motor taking account the broken bars faul t nd the stator current spectrum analysis (FFT). Keywords—Rotor faults, diagnosis, induction motor, DTC, stat or current spectrum.

Applications of Support Vector Machines on Smart Phone Systems for Emotional Speech Recognition

Abstract: An emotional speech recognition system for the applications on smart phones was proposed in this s tudy to combine with 3G mobile communications and social networks to provide users with more interaction and care from their gro ups. This study developed a mechanism using the support vector machines (SVM) to recognize the emotions of users' speech such as hap piness, anger, sadness and normal. The mechanism uses a hierarchical classifier to adjust the weights of acoustic features and divides various parameters into the categories of energy and freque ncy for training. In this study, 28 commonly used acoustic features i ncluding pitch and volume were proposed for training. In addition, a time-frequency parameter obtained by continuous wavelet transforms was also used to identify the accent and intonation in a sentence during the recognition process. The Berlin Database of Emotion al Speech was used by dividing the speech into male and female da ta sets for training. According to the experimental results, th e accuracies of male and female test sets were increased by 4.6% an d 5.2% respectively after using the time-frequency paramet er for classifying happy and angry emotions. For the classification of all emotions, the average accuracy, including male and female data, was 63.5% for the test set and 90.9% for the whole data set.

Authentication Protocol for Wireless Sensor Networks

Abstract: Wireless sensor networks can be used to measure and monitor many challenging problems and typically involve in monitoring, tracking and controlling areas such as battlefield monitoring, object tracking, habitat monitoring and home sentry systems. However, wireless sensor networks pose unique security challenges including forgery of sensor data, eavesdropping, denial of service attacks, and the physical compromise of sensor nodes. Node in a sensor networks may be vanished due to power exhaustion or malicious attacks. To expand the life span of the sensor network, a new node deployment is needed. In military scenarios, intruder may directly organize malicious nodes or manipulate existing nodes to set up malicious new nodes through many kinds of attacks. To avoid malicious nodes from joining the sensor network, a security is required in the design of sensor network protocols. In this paper, we proposed a security framework to provide a complete security solution against the known attacks in wireless sensor networks. Our framework accomplishes node authentication for new nodes with recognition of a malicious node. When deployed as a framework, a high degree of security is reachable compared with the conventional sensor network security solutions. A proposed framework can protect against most of the notorious attacks in sensor networks, and attain better computation and communication performance. This is different from conventional authentication methods based on the node identity. It includes identity of nodes and the node security time stamp into the authentication procedure. Hence security protocols not only see the identity of each node but also distinguish between new nodes and old

Enhanced particle swarm optimization approach for solving the non-convex optimal power flow

Abstract: An enhanced particle swarm optimization algorithm (PSO) is presented in this work to solve the non-convex OPF problem that has both discrete and continuous optimization variables. The objective functions considered are the conventional quadratic function and the augmented quadratic function. The latter model presents non-differentiable and non-convex regions that challenge most gradient-based optimization algorithms. The optimization variables to be optimized are the generator real power outputs and voltage magnitudes, discrete transformer tap settings, and discrete reactive power injections due to capacitor banks. The set of equality constraints taken into account are the power flow equations while the inequality ones are the limits of the real and reactive power of the generators, voltage magnitude at each bus, transformer tap settings, and capacitor banks reactive power injections. The proposed algorithm combines PSO with Newton-Raphson algorithm to minimize the fuel cost function. The IEEE 30-bus system with six generating units is used to test the proposed algorithm. Several cases were investigated to test and validate the consistency of detecting optimal or near optimal solution for each objective. Results are compared to solutions obtained using sequential quadratic programming and Genetic Algorithms. Keywords—Particle Swarm Optimization, Optimal Power Flow, Economic Dispatch.

An Optimized Design of Non-uniform Filterbank

Abstract: The tree structured approach of non-uniform filterbank (NUFB) is normally used in perfect reconstruction (PR). The PR is not always feasible due to certain limitations, i.e, constraints in selecting design parameters, design complexity and some times output is severely affected by aliasing error if necessary and sufficient conditions of PR is not satisfied perfectly. Therefore, there has been generalized interest of researchers to go for near perfect reconstruction (NPR). In this proposed work, an optimized tree structure technique is used for the design of NPR non-uniform filterbank. Window functions of Blackman family are used to design the prototype FIR filter. A single variable linear optimization is used to minimize the amplitude distortion. The main feature of the proposed design is its simplicity with linear phase property. Keywords—Tree structure, NUFB, QMF, NPR.

An Energy Reverse AODV Routing Protocol in Ad Hoc Mobile Networks

Abstract: In this paper we present a full performance analysis of an energy conserving routing protocol in mobile ad hoc network, named ER-AODV (Energy Reverse Ad-hoc On-demand Distance Vector routing). ER-AODV is a reactive routing protocol based on a policy which combines two mechanisms used in the basic AODV protocol. AODV and most of the on demand ad hoc routing protocols use single route reply along reverse path. Rapid change of topology causes that the route reply could not arrive to the source node, i.e. after a source node sends several route request messages, the node obtains a reply message, and this increases in power consumption. To avoid these problems, we propose a mechanism which tries multiple route replies. The second mechanism proposes a new adaptive approach which seeks to incorporate the metric \"residual energy \" in the process route selection, Indeed the residual energy of mobile nodes were considered when making routing decisions. The results of simulation show that protocol ER-AODV answers a better energy conservation. Keywords—Ad hoc mobile networks, Energy AODV, Energy consumption, ER-AODV, Reverse AODV.

Medical Image Segmentation Based On Vigorous Smoothing and Edge Detection Ideology

Abstract: smoothing followed by edge detection assumes a great degree of importance in the field of Image Processing. In this regard, this paper proposes a novel algorithm for medical image segmentation based on vigorous smoothening by identifying the type of noise and edge diction ideology which seems to be a boom in medical image diagnosis. The main objective of this algorithm is to consider a particular medical image as input and make the preprocessing to remove the noise content by employing suitable filter after identifying the type of noise and finally carrying out edge detection for image segmentation. The algorithm consists of three parts. First, identifying the type of noise present in the medical image as additive, multiplicative or impulsive by analysis of local histograms and denoising it by employing Median, Gaussian or Frost filter. Second, edge detection of the filtered medical image is carried out using Canny edge detection technique. And third part is about the segmentation of edge detected medical image by the method of Normalized Cut Eigen Vectors. The method is validated through experiments on real images. The proposed algorithm has been simulated on MATLAB platform. The results obtained by the simulation shows that the proposed algorithm is very effective which can deal with low quality or marginal vague images which has high spatial redundancy, low contrast and biggish noise, and has a potential of certain practical use of medical image diagnosis.

Design of Permanent Magnet Machines with Different Rotor Type

Abstract: This paper presents design, analysis and comparison of the different rotor type permanent magnet machines. The presented machines are designed as having same geometrical dimensions and same materials for comparison. The main machine parameters of interior and exterior rotor type machines including eddy current effect, torque-speed characteristics and magnetic analysis are investigated using MAXWELL program. With this program, the components of the permanent magnet machines can be calculated with high accuracy. Six types of Permanent machines are compared with respect to their topology, size, magnetic field, air gap flux, voltage, torque, loss and efficiency. The analysis results demonstrate the effectiveness of the proposed machines design methodology. We believe that, this study will be a helpful resource in terms of examination and comparison of the basic structure and magnetic features of the PM (Permanent magnet) machines which have different rotor structure.

Application of Four-electrode Method to Analysis Resistance Characteristics of Conductive Concrete

Abstract: The purpose of this paper is to discuss the influen ce of resistance characteristic on the high conductive co ncrete considering the various voltage and environment. The four-elect rode method is applied to the tailor-made high conductive concrete with appropriate proportion. The curve of resistivity with the chang es of voltage and environment is plotted and the changes of resistivi ty are explored. The result based on the methods reveals that resistivit y is less affected by the temperature factor, and the four-electrode meth od would be an applicable measurement method on a site inspection. Keywords—Conductive concrete, Resistivity.

Energy Efficient Reliable Cooperative Multipath Routing in Wireless Sensor Networks

Abstract: In this paper, a reliable cooperative multipath routing algorithm is proposed for data forwarding in wireless sensor networks (WSNs). In this algorithm, data packets are forwarded towards the base station (BS) through a number of paths, using a set of relay nodes. In addition, the Rayleigh fading model is used to calculate the evaluation metric of links. Here, the quality of reliability is guaranteed by selecting optimal relay set with which the probability of correct packet reception at the BS will exceed a predefined threshold. Therefore, the proposed scheme ensures reliable packet transmission to the BS. Furthermore, in the proposed algorithm, energy efficiency is achieved by energy balancing (i.e. minimizing the energy consumption of the bottleneck node of the routing path) at the same time. This work also demonstrates that the proposed algorithm outperforms existing algorithms in extending longevity of the network, with respect to the quality of reliability. Given this, the obtained results make possible reliable path selection with minimum energy consumption in real time.

The Comparison Study of Harmonic Detection Methods for Shunt Active Power Filters

Abstract: The paper deals with the comparison study of harmonic detection methods for a shunt active power filter. The %THD and the power factor value at the PCC point af ter compensation are considered for the comparison. The re are three harmonic detection methods used in the paper that a re synchronous reference frame method, synchronous detection metho d, and DQ axis with Fourier method. In addition, the ideal current source is used to represent the active power filter by assuming an in finitely fast controller action of the active power filter. The s imulation results show that the DQ axis with Fourier method provides the minimum %THD after compensation compared with other methods . However, the power factor value at the PCC point after compe nsation is slightly lower than that of synchronous detection method. Keywords—Harmonic detection, shunt active power filter, DQ axis with Fourier, power factor.

Multiobjective Optimization Solution for Shortest Path Routing Problem

Abstract: The shortest path routing problem is a multiobjective nonlinear optimization problem with constraints. This problem has been addressed by considering Quality of service parameters, delay and cost objectives separately or as a weighted sum of both objectives. Multiobjective evolutionary algorithms can find multiple pareto-optimal solutions in one single run and this ability makes them attractive for solving problems with multiple and conflicting objectives. This paper uses an elitist multiobjective evolutionary algorithm based on the Non-dominated Sorting Genetic Algorithm (NSGA), for solving the dynamic shortest path routing problem in computer networks. A priority-based encoding scheme is proposed for population initialization. Elitism ensures that the best solution does not deteriorate in the next generations. Results for a sample test network have been presented to demonstrate the capabilities of the proposed approach to generate well-distributed pareto-optimal solutions of dynamic routing problem in one single run. The results obtained by NSGA are compared with single objective weighting factor method for which Genetic Algorithm (GA) was applied. Keywords—Multiobjective optimization, Non-dominated Sorting Genetic Algorithm, Routing, Weighted sum.

Evaluation of Energy-Aware QoS Routing Protocol for Ad Hoc Wireless Sensor Networks

Abstract: Many advanced Routing protocols for wireless sensor networks have been implemented for the effective routing of data. Energy awareness is an essential design issue and almost all of these routing protocols are considered as energy efficient and its ultimate objective is to maximize the whole network lifetime. However, the introductions of video and imaging sensors have posed additional challenges. Transmission of video and imaging data requires both energy and QoS aware routing in order to ensure efficient usage of the sensors and effective access to the gathered measurements. In this paper, the performance of the energy-aware QoS routing Protocol are analyzed in different performance metrics like average lifetime of a node, average delay per packet and network throughput. The parameters considered in this study are end-to-end delay, real time data generation/capture rates, packet drop probability and buffer size. The network throughput for realtime and non-realtime data was also has been analyzed. The simulation has been done in NS2 simulation environment and the simulation results were analyzed with respect to different metrics. Keywords— Cluster Nodes, end-to-end delay, QoS routing, Routing Protocols, Sensor Networks, least-cost-path