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28,593 Article Results

Handover Scenarios for Mobile WiMAX and Wireless LAN Heterogeneous Network

10.11591/ijeecs.v12.i8.pp6313-6323
NMAED Wirastuti , CCW Emehel
This paper presents proposed handover scenarios for a heterogeneous network comprising mobile worldwide interoperability for Microwave Access and Wireless Local Area Network segments. Homogenous handover scenarios for a mobile WiMAX network are also considered to allow a comparative analysis. A mobile node supporting voice traffic is analysed, when operating in a half-cell overlap coverage scenario, for both pedestrian and vehicular speeds. All proposed handover scenarios are assessed and validated through system-level Media Independent Handover network simulations. Results for both homogenous and heterogeneous handover show that the handover delay and jitter are within the acceptable values published by the WiMAX Forum. For heterogeneous handover, the packet loss is negligible for all cases; however, there were significant occurrences of packet loss in throughput for homogenous handover at vehicular speeds. This is due to the fact that the implementation of an adaptive channel scanning algorithm to allocate scanning intervals can limit communication disruptions.
Volume: 12
Issue: 8
Page: 6313-6323
Publish at: 2014-08-01

Hybrid PSOGSA Method of Solving ORPD Problem with Voltage Stability Constraint

10.11591/ijeecs.v12.i8.pp5807-5813
J. Jithendranath , A.Srihari Babu , G.Durga Sukumar
This paper presents a new hybrid evolutionary based algorithm based on PSO and GSA for solving optimal reactive power dispatch problem in power system. The problem was designed as a Multi-Objective case with loss minimization and voltage stability as objectives. Generator terminal voltages, tap setting of transformers and reactive power generation of capacitor banks were taken as optimization variables. Modal analysis method is adopted to assess the voltage stability of system. The above presented problem was solved on basis of efficient and reliable technique which takes the advantages of both PSO and GSA. The proposed method has been tested on IEEE 30 bus system where obtained results were found satisfactorily to a large extent that of reported earlier.
Volume: 12
Issue: 8
Page: 5807-5813
Publish at: 2014-08-01

Enhancement Fault Ride-Through Capability of DFIG By Using Resistive and Inductive SFCLs

10.11591/ijeecs.v12.i8.pp5946-5953
Ali Azizpour , Mehdi Hosseini , Mahmoud Samiei Moghaddam
The number of wind turbines connected to the grid is steadily increasing in recent years. This situation forced the revision of the electric utilities grid codes requirements, to remain connected during grid faults, i.e., to ride through the faults, especially for those with power electronic converters, such as DFIGs. In fault condition, the voltage at the Point of Common Coupling (PCC) drops immediately and The grid voltage dips imposed at the connection point of the DFIG to the grid induce large voltages in the rotor windings, resulting in high rotor current, which can damage the rotor-side converter and disconnect from grid.  In this paper, resistive and inductive superconducting fault current limiter (SFCL) is used to improve the fault ride- through (FRT) of wind turbine generation system (WTGS). The WTGS is considered as a variable-speed system, equipped with a DFIG. The analytical and simulation studies of the resistive SFCL for improving FRT capability are presented and compared with the inductive SFCL.
Volume: 12
Issue: 8
Page: 5946-5953
Publish at: 2014-08-01

Chaos Based Image Encryption using Expand-Shrink Concept

10.11591/ijict.v3i2.pp103-112
Naveenkumar S K , Panduranga H T , Kiran P
Image information security plays a vital role in computing and communication technologies. This paper describes a new concept of expand and shrink to enhance the strength of chaos based image encryption technique. This method consists of both permutations as well as substitution process for image scrambling and encryption. In permutation plain image is shuffled using chaos technique. Input image undergo two times chaos permutation in-between expand and shrink process leads to substitution. Permutation decreases the correlation between the pixel and substitution increases the entropy of encrypted image. Proposed encryption technique works for both gray-scale and color image. From the experiment highly scrambled image is obtained at the end of encryption process. Decryption process employs exactly reverse process of encryption which results in the reconstructed images.
Volume: 3
Issue: 2
Page: 103-112
Publish at: 2014-08-01

Impact of FFT algorithm selection on switching activity and coefficient memory size

10.11591/ijeecs.v12.i8.pp6224-6229
Imran Ali Qureshi , Fahad Qureshi
The binary tree decomposition allows for obtaining a large number of algorithms that can be used to calculate the fast Fourier transform. This paper analyzes the differences among these algorithms in terms of switching activity, which is related to the power consumption of the circuit, and size of the coefficient memories, which is related to the area of the circuit.Experimental results show the most efficient algorithms in term of area and power consumption. Furthermore, the paper shows the importance of a proper algorithm selection, since efficient algorithms can lead to savings of upto 45% in terms of the coefficient memory and even greater than 50% in terms of switching activity with respect to other less efficient ones.
Volume: 12
Issue: 8
Page: 6224-6229
Publish at: 2014-08-01

Fuzzy Sliding Mode Control of PEM Fuel Cell System for Residential Application

10.11591/ijeecs.v12.i8.pp6017-6026
Mahdi Mansouri , Mohammad Ghadimi , Kamal Abbaspoor Sani
Proton exchange membrane fuel cells (PEMFCs) are receiving more attention compared with other sources of power generation. Maintaining a fuel cell system requires excellent system control to receive the best operating. Therefore, in this paper a dynamic model of a (PEMFC) for residential power generation is applied. The model proposed includes the fuel cell stack model, power condition unite that consists of the methanol reformer model and DC-AC inverter model. According to power output of (PEM) fuel cell system, a fuzzy sliding mode controller which contains the characteristics of fuzzy control and sliding mode control is addressed, in order to modify the hydrogen flow feedback from the terminal load. In addition, this combined controller is used to improve stability by fuzzy reasoning to control the output variation that reduces chattering and increase the speed of tracking by reasoning of sliding mode control. Consequently, the dynamical behavior of system with FSMC is more improved as compared to the FLC and PI controller in terms of rate of hydrogen flow, output AC voltage and output power of FC and it is shown that the proposed controller can achieve better control effect than other controllers.
Volume: 12
Issue: 8
Page: 6017-6026
Publish at: 2014-08-01

IR-UWB: An Ultra Low Power Consumption Wireless communication Technologie for WSN

10.11591/ijeecs.v12.i8.pp5699-5708
Anouar Darif , Rachid Saadane , Driss Aboutajdine
Wireless Sensor Network (WSN) has gained popularity in recent times in residential, commercial and industrial applications. Several wireless technologies have emerged ranging from short and medium distances.  Bluetooth, ZigBee and Impulse Radio Ultra Wide Band (IR-UWB) are three short range wireless communications. There are several features of IR-UWB signals which make them attractive for a short range of wireless applications. Some of the major advantages of IR-UWB are, low complexity, ultra low power consumption, and good time-domain resolution allowing for location and tracking applications. In this paper, we provide a performance study of these popular wireless communication technologies, evaluating the main features and advantages of IR-UWB for WSN in terms of the transmission time and power consumption. We used MiXiM platform under OMNet++ simulator to analyze and evaluate the main features of IR-UWB.
Volume: 12
Issue: 8
Page: 5699-5708
Publish at: 2014-08-01

Fault Location of Distribution Network Containing Distributed Generations

10.11591/ijeecs.v12.i8.pp5910-5917
Zou Bi-Chang , Zhou Hong
It makes the topology of distribution network more complex to contain a lot of distribution generations (DGs) in it. For this reason, a fault location approach suitable to the distribution network containing DGs is proposed. Firstly, according to the results of power flow calculation, a database of voltage sag is established; then the power quality information is acquired by power quality monitors and correlation analysis on collected nodal voltage data and voltage sag data of the established database is performed; and then the node with the matching extent value most close to 1 is determined as the fault point. Simulation results of IEEE 33-bus system show that the proposed approach is effective and using the proposed approach the misjudgment can be prevented. Finally, the results of the analysis on the influences of different load models, transition resistances, connection and disconnection of DGs on the proposed approach show that the proposed approach possesses better robustness and reliability.
Volume: 12
Issue: 8
Page: 5910-5917
Publish at: 2014-08-01

Peak Load Chopping Applying Fuzzy Bayesian Technique For Regional Load Management-Performance Evaluation

10.11591/ijeecs.v12.i8.pp5963-5968
Arindam Kumar Sil , N. K. Deb , Ashok Kumar Maitra
In this paper Fuzzy Bayesian Synthetic algorithm based methodology has been evaluated for its performance using real time data for chopping off peak load demand. This is achieved by judiciously scheduling load from the regional load under a new load management technique. This technique validates the timely decision making capacity of the system to reduce peak demand hence giving us a chance to reduce the peak demand and hence reduce the stress of generating excess power during the peak period. This method uses data of a previous day and then predicts for the next day. Thus by evaluating this process it was found that the new peak demand has a reduced value as compared to the actual peak demand. It is evident that this method can not only reduce peak demand by chopping of the regional loads by following the proposed algorithm but also helps in generating indirect revenue by saving energy. This method authenticates the proposed method and saves peak demand or otherwise energy by about ten to fifty megawatts on daily basis depending on the service condition of the network and solar day light hour availability over span of a day.
Volume: 12
Issue: 8
Page: 5963-5968
Publish at: 2014-08-01

Slice Interpolation for MRI Using Disassemble-Reassemble Method

10.11591/ijeecs.v12.i8.pp6190-6197
Qinghua Lin , Min Du
Due to physical limitations inherent in Magnetic resonance image (MRI) scanners, the inter-slice resolution of MRI is coarse. Thus, interpolation is often used to compensate it. MRI corresponds to a thin slice through the human body, and contains all the information in the slice. Based on this characteristic, a novel slice interpolation algorithm using disassemble-reassemble (D-R) method is proposed for doing MRI slice interpolation. The algorithm first disassembles all the information contained in MRI, and then reassembles them under a heuristic approach of neighborhood consistency to get higher inter-slice resolution. Series virtual images that imitate the characteristic of MRI were used to explain the principle of proposed algorithm, and the process of proposed algorithm was derived from detail analysis. Finally, we performed a large number of interpolation experiment and compared the proposed algorithm to several other interpolation techniques. Results show that the proposed algorithm outperforms the other interpolation algorithms, which means the D-R method is more suitable for MRI interpolation.
Volume: 12
Issue: 8
Page: 6190-6197
Publish at: 2014-08-01

Load Balancing Based on the Specific Offset of Handover

10.11591/ijeecs.v12.i8.pp6281-6290
Liu Zhanjun , Ma Qichao , Ren Cong , Chen Qianbin
Load Balancing technology in mobile wireless communication networks has been discussed largely. The current Load balancing algorithms have mainly adjusted the handover parameters without considering the inherent relationship of the handover parameters. In the paper, by considering the internal relationship of specific offset of handover, the constraint of the specific offser of handover was simplified, so the process of mobility load balancing algorithm was improved. With the improved mobile load balancing algorithm, the number of handover parameters was reduced and the signal process was simplified. Simulation results showed that the congestion rate  was reduced, the resource utilization rate was  improved and the Qos was improved.
Volume: 12
Issue: 8
Page: 6281-6290
Publish at: 2014-08-01

A Novel Clustering Routing Protocol in Wireless Sensor Network

10.11591/ijeecs.v12.i8.pp6267-6273
Wu Rui , Xia Kewen , Bai Jianchuan , Zhang Zhiwei
The phenomenon of network resource-constrained often appears in wireless sensor network (WSN) because of nodes with energy-limited, so it becomes a research topic to study on high-performance routing protocol in wireless sensor network. In accordance with the characteristic of quantum particle swarm optimization (QPSO), a novel clustering routing protocol with QPSO algorithm is proposed based on the low energy adaptive clustering hierarchy (LEACH), which includes several steps, such as determining the number of cluster-head, preliminary clustering, optimization on temporary cluster by QPSO algorithm, clustering after optimization, and so on. Comparative analysis on simulation experiments show that the proposed routing protocol is superior to that of LEACH, and saves energy consumption of network excellently and balances energy of nodes so as to prolong the life of the network.
Volume: 12
Issue: 8
Page: 6267-6273
Publish at: 2014-08-01

Modeling and Analyzing for the Friction Torque of a Sliding Bearing Based on Grey System Theory

10.11591/ijeecs.v12.i8.pp6009-6016
Wang Baoming , Xu Jinxin , Chen ShengSheng , Wu Zaixin
Based on the grey system theory, the grey relational analysis method is proposed and used in analyzing the influence of various factors on the friction torque of a sliding bearing. On the basis of the grey relational analysis the multidimensional grey model GM(1,N,D) for the friction torque of a sliding bearing is built up. Taking Al-based alloy sliding bearing as an example, the calculation results show that, compared with other influence factors, friction coefficient, load, temperature and rotational speed have more significant influence on the bearing friction torque.Comparingexperimental results and the calculated value of the GM(1,N,D) model based on these important influence factors, the maximum relative residuals is 9.09%, the average relative residuals is 7.9% and the accuracy is 92.1%. It verify that GM(1,N,D) model has good accuracy and is applicable for predicting friction torque of a sliding bearing.
Volume: 12
Issue: 8
Page: 6009-6016
Publish at: 2014-08-01

An Overview of Electrical Tree Growth in Solid Insulating Material with Emphasis of Influencing Factors, Mathematical Models and Tree Suppression

10.11591/ijeecs.v12.i8.pp5827-5846
M.H. Ahmad , N. Bashir , H. Ahmad , A.A. Abd Jamil , A.A. Suleiman
Nowadays, the most widely used insulating materials in high voltage equipment such as cables are polymeric insulations due to the numerous merits they possess with regards to electrical performance compared to paper insulations. However, electrical treeing, one of the dielectric pre-breakdown phenomena, has been considered as a major contribution to the failure of insulating polymeric materials. Thus, this paper provides an overview on the factors affecting the initiation and propagation of electrical tree.  Discussions on parameters that affect the growth of electrical treeing such as applied voltage, electric field enhancement, partial discharge, frequency of applied voltage and temperature are given. Some discussions on the various models are also highlighted. The tree related models being discussed herein include Weibull, Lognormal, Johnson SB, Dielectric Breakdown Model, Discharge-Avalanche Model, and Field-Driven Tree Growth. In addition, discussions on the use of nano-sized fillers in polymeric insulating material to inhibit electric treeing are highlighted.
Volume: 12
Issue: 8
Page: 5827-5846
Publish at: 2014-08-01

Control Strategy of Three Phase PWM by Three Half Bridge Topology Bidirectional DC/DC Converter and Resonant

10.11591/ijeecs.v12.i8.pp6111-6118
Dingzhen Li , Haizhen Guo
This paper analyses and compares PWM control strategy of control and buffer type soft switching half bridge DC/DC converter. Finally, the soft switching condition are analyzed, and this article gets the realization of soft switching conditions of the three half bridge DC/DC converter and the influence factors of soft switching conditions of the three half bridge DC/DC converter. Characteristics of resonant converter can boost and buck, so the output voltage stable strategy of variable frequency control is more easily achieved. The paper presents control strategy of three phase PWM by three half bridge topology bidirectional DC/DC converter and resonant.
Volume: 12
Issue: 8
Page: 6111-6118
Publish at: 2014-08-01
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