|Title: An Effective Technique Using Finite Element Methods|
|Author(s): Sabah Tamimi|
|Pages: 01-05||Paper ID: 121402-9595-IJECS-IJENS||Published: April, 2012|
Abstract: A finite element method (FEM) has been used for determination of confined turbulent flow with a one equation model to depict the turbulent viscosity which is applied to a smooth straight channel. The effect of a zone close to a solid wall has been investigated by imposing a technique to model this zone for predicting the distribution of the pertinent variables in this zone. The validity of the imposed technique is shown by comparison with other techniques.
|Keywords: Incompressible turbulent flow, pressure flow, wall element technique, FEM|
|Full Text (.pdf) | 875 KB|
|Title: Adaptive Neuro-Fuzzy Approach for the Power System Stabilizer Model in Multi-machine Power System|
|Author(s): Agus Jamal, Ramadoni Syahputra|
|Pages: 06-13||Paper ID: 122502-8484-IJECS-IJENS||Published: April, 2012|
Abstract: This paper proposes an adaptive neuro-fuzzy approach for designing robust power system stabilizers (PSS) in order to improve the stability of a multi-machine power system under fault conditions. Simulations were carried out using several fault tests at transmission line on a Two-Area Multi-machine Power System that consists of four machine and ten buses. The system is simulated in Simulink Software while the PSS is implemented using Fuzzy Logic Toolbox in Matlab. As a reference the PSS model, Delta w PSS has been used for comparison with the PSS under consideration. The result shows that power transfer response using the model is more robust than Delta w PSS, especially for both single line to ground fault and symmetrical three phase fault.
|Keywords: Power system stabilizer, transient stability, multi-machine power system, neuro-fuzzy adaptive|
|Full Text (.pdf) | 355 KB|
|Title: A LPC-PEV Based VAD for Word Boundary Detection|
|Author(s): Syed Abbas Ali, NajmiGhaniHaider, Mahmood Khan Pathan|
|Pages: 14-22||Paper ID: 123402-0707-IJECS-IJENS||Published: April, 2012|
Abstract: The speech is the prominent mode of communication and interaction among human being and machines. In most of the practical application of ASR, the input speech is contaminated by ambient noise. In this paper LPC-PEV algorithm is proposed for word boundary detection in the presence of noise. In the proposed algorithm, the variance of error is estimated by AR model using Yule Walker method. We used the speech and noise samples taken from TIDIGIT corpus and NOISE-92 databases respectively, and evaluated the performance of system using LPC-PEV and LPC residual error. The experimental results based on numerical values of the samples clearly evident that the boundary detection rate of proposed algorithm is far better than the LPC residual error in term of clean and noisy speech.
|Keywords: Predictive capability, Linear prediction coefficient, precision, Residual error, Prediction error variance (PEV)|
|Full Text (.pdf) | 2287 KB|
|Title: Semiconductor Material And Process Characterization Using Three Probes|
|Author(s): Ateeq Ahmad Khan|
|Pages: 23-27||Paper ID: 123902-7575-IJECS-IJENS||Published: April, 2012|
Abstract: One of the most powerful techniques of semiconductor material and process characterization is the use of three probes in spreading resistance configuration. The raw data thus obtained needs analysis for extracting profiling information. The problem of poor spatial resolution of Spreading Resistance measurements on shallow doped layers has been taken up. An analysis of the raw spreading resistance data is made and a technique is developed for the correction of these data and their utilization in profiling the doped samples. The technique includes both the areas of application, namely the lateral profiling across the surface of the doped samples and the depth profiling of the doped layers using beveled samples. The mathematical model developed for the analyses is in conformity with the physical set up of the experimental measurements. The results of the analysis in both the above stated cases are presented. The resulting corrected spreading resistance data are in good agreement with the values obtained by the other well established methods.
|Keywords: Spreading resistance, spatial resolution, semiconductor material, doping, and diffusion|
|Full Text (.pdf) | 109 KB|
|Title: Optimal control of variable-speed wind energy conversion system based on fuzzy model power curve|
|Author(s): Agus Naba, Ahmad Nadhir, Takashi Hiyama|
|Pages: 28-36||Paper ID: 125002-3838-IJECS-IJENS||Published: April, 2012|
Abstract: Performance optimization of variable-speed wind energy conversion system (WECS) is presented here from a practical point of view against poorly known model and parameters of the system working in the partial load region. The proposed approach is to approximate the power curve by using a fuzzy model that uses the generator rotor speed and the wind speed as the inputs and the generator power as the output. The fuzzy model is required to well estimate only a few number of the maximum generator power points, thus less effort for its training. The data pairs of the generator rotor speed and the wind speed at which the fuzzy model gives the maximum estimation of the generator power are used to develop a control law using the regression method. Well chosen data pairs enable the regression method to result in an optimal control law, mapping any given wind speed within the partial load region into an optimal rotor speed. Applied to control a squirrel-cage induction generator based WECS, the optimal control law has successfully maximized the performance of the WECS and is robust with respect to inaccuracies in its parameters. This was verified by the high power coefficients achieved at almost all times despite wind speed variations and the inaccurate control law parameters used.
|Keywords: Optimal control, fuzzy model, power curve, wind energy conversion system|
|Full Text (.pdf) | 248 KB|
|Title: Towards Performance Evaluation of Rate Control Protocol in Satellite Networks|
|Author(s): Y. D. Sun, Z. Z. Ji, H. Wang|
|Pages: 37-41||Paper ID: 126802-4747-IJECS-IJENS||Published: April, 2012|
Abstract: The research of congestion control has recently been focused on the explicit and rate-based mechanism. RCP (Rate Control Protocol) is an explicit and rate-based mechanism which emulates PS (Processor Sharing) to reduce the AFCT (Average Flow Completion Time). There are few studies considering RCP in satellite networks although RCP has some promising virtues. Therefore, this paper explored the performance of RCP thoroughly through simulations in NS2. The results of simulations show that RCP has high throughput and is not affected by BER (Bit Error Rates). But some drawbacks such as flash crowd, long response time and TCP-unfriendliness were found.
|Keywords: Congestion Control, RCP, Satellite Networks, Flash Crowd|
|Full Text (.pdf) | 890 KB|