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28,593 Article Results

Sequence Clustering Algorithm Based on Weighed Sequential Pattern Similarity

10.11591/ijeecs.v12.i7.pp5529-5536
Di Wu , Jiadong Ren
Sequence clustering has become an active issue in the current scientific community. However, the clustering quality is affected heavily by selecting initial clustering centers randomly. In this paper, a new sequence similarity measurement based on weighed sequential patterns is defined. SCWSPS (Sequence Clustering Algorithm Based on Weighed Sequential Pattern Similarity) algorithm is proposed. Sequences with the largest weighted similarity are chosen as the merge objects. The last K-1 synthesis results are deleted from sequence database. Others sequences are divided into K clusters. Moreover, in each cluster, the sequence which has the largest sum of similarities with other sequences is viewed as the updated center. The experimental results and analysis show that the performance of SCWSPS is better than KSPAM and K-means in clustering quality. When the sequence scale is very large, the execution efficiency of SCWSPS is slightly worse than KSPAM and K-means.
Volume: 12
Issue: 7
Page: 5529-5536
Publish at: 2014-07-01

Three-Dimensional Thermal Analysis of Three-Phase Enclosed GIS Bus Bars

10.11591/ijeecs.v12.i7.pp5003-5010
Hongtao Li , Naiqiu Shu , Ling Li
The ampacity of GIS bus bars is limited by the maximum operation temperature of the contacts. This paper employs the coupled eddy current, fluid and thermal finite-element method (FEM) to solve the three-dimensional (3-D) heat transfer problem in a three-phase enclosed GIS bus bar. The contact resistance is considered and described as a resistor between the conductor and the contact finger. In order to avoid convective boundary condition on the tank surface which is not easy to apply, the ambient air is introduced into the solution region. The temperature dependent thermal properties of SF6 gas and air are considered. The temperatures calculated by proposed model are found to be in good agreement with the experimental data of a 126 kV three-phase enclosed bus bar prototype.
Volume: 12
Issue: 7
Page: 5003-5010
Publish at: 2014-07-01

Circuit Design of Digital Closed Loop Control System for FOG

10.11591/ijeecs.v12.i7.pp5174-5184
Qiudong Sun , Yufeng Shao , Jiancun Zuo , Liandong Wang , Lin Gui
Fiber optic gyroscope (FOG) is a new angular rate sensor based on the Sagnac effect. It has been widely applied in the navigation control system of aircrafts, spacecrafts and ships. But its stability, reliability and miniaturization are always the research focuses and difficulties. This paper presented a circuit design method for the digital closed loop control system of FOG based on FPGA. Based on a large number of experiments, this paper summarized the parameter demands for each module of closed loop control circuit and designed a corresponding circuit using FPGA. The proposed dual closed loop technique improved the zero offset stability of FOG. The using of FPGA brought the digital signal processing by software, the system reliability and agility enhancement as well as the system miniaturization. Particularly, we discussed the problems of component   selection and the anti-jamming measures for PCB design to improve the performances of the system. We also developed some samples of FOG using this design method. The experiments and tests show that the proposed method is efficient and valuable. The stabilities of zero-offsets of all samples are less than 0.075deg/h.
Volume: 12
Issue: 7
Page: 5174-5184
Publish at: 2014-07-01

Determining LBMP through Optimal Power Flow in the Electric Power Business

10.11591/ijeecs.v12.i7.pp5086-5095
Hermagasantos Zein , Yusra Sabri , Erwin Dermawan
The energy crisis has got the serious attention of experts since the middle19th century. Many efforts with significant progresses has been yielded to obtain its solution, such as technology development and diversification of primary energy sources, but the threat of the energy crisis has not been able to be avoided. Early tahun 1990, attention of experts are focused on energy savings, operating efficiencies and transparency. As a result, they have recommended changing the electric power business of the monopoly system to the market system, competition. In a competitive system, the problems will be more complex, especially in the energy price through optimization. One of the popular energy pricing methods today is LBMP, Locational Based Marginal Price, which has been successfully applied by New York, US. Generally, it is determined through ED, Economic Dispatch, calculations. In this case, Operator must do the complicated adjustments, especially for congestion conditions, so that thier results can be applied to the network. The simulation results, both heavy and light loads, showed that the OPF with step reduction can work well. Comparing with ED has to done some adjustments because a few contraints were out of their limits.
Volume: 12
Issue: 7
Page: 5086-5095
Publish at: 2014-07-01

Digital Image Stabilization Based on Improved Scale Invariant Feature Transform

10.11591/ijeecs.v12.i7.pp5645-5654
Xiaoran Guo , Shaohui Cui , Dan Fang
A novel digital image stabilization approach using Harris and Scale Invariant Feature Transform (SIFT) was presented in this article. Using SIFT in digital image stabilization, too many feature points and matches were extracted, but some of them were not so stable. Using these feature points and matches can not only increase the computational effort, but also enhance the wrong matching probability. We proposed to use SIFT to detect feature points and incorporate the Harris criterion to select the most stable feature points in the video sequence where image motion was happened due to vehicle or platform vibration. With these feature points, we use general feature descriptor and matching algorithm to achieve the image stabilization. Experimental results show that the proposed algorithm can not only bring down the probability of wrong matching and get more accurate matches, but also reduce the computation burden than SIFT effectively.
Volume: 12
Issue: 7
Page: 5645-5654
Publish at: 2014-07-01

Research on Zigbee Network Temperature Sensor in Intelligent High-Voltage Switch Cabinet

10.11591/ijeecs.v12.i7.pp4963-4972
Xin-bo Huang , Yang Zhao , Xiao-hui Zhao , Zhi-jun Liao
The contacts of high-voltage switchgear will heat and cause safety hazards due to poor contact while running. A Zigbee-based wireless network sensor was designed by the authors of this paper for real-time monitoring of high voltage switchgear when contact temperature rises. This paper first gives a brief introduction to the Zigbee protocol, the protocol stack and the network topology, and then makes an elaboration on the system framework, hardware and software designs of the Zigbee wireless sensor and the design of high-voltage bootstrap power supply. In the end, the field application and analysis proves that based on the Zigbee technology, the online monitoring system of the temperature rise for high-voltage switchgear is stable and capable of real-time reporting the true temperature of the contact. Therefore, the design has the characteristics of high stability, low power consumption, low cost, as well as high flexibility and scalability.
Volume: 12
Issue: 7
Page: 4963-4972
Publish at: 2014-07-01

Investigating the Effect of Different PWM Modes on Ripple Reduction in Five-Phase BLDC Motor with New Method

10.11591/ijeecs.v12.i7.pp5129-5136
Seyed Mohsen Mirbagheri , Seyed Sajjad Salehi GHalehsefid , Seyed Mohammad Hossein Mousavi
Torque ripple is one of the main drawbacks of  brushless DC motors.  in the case of three phase motors, PWM modes have a significant effect on the generated torque ripple. So, like three phase BLDC motors, we investigate the effect of different PWM modes on torque ripple of five-phase BLDC motor that has less torque ripple  in high speed. in this investigation we will show that freewheeling current in inactive phase is important factor in torque ripple. Also simulation in matlab/Simulink prove this event.
Volume: 12
Issue: 7
Page: 5129-5136
Publish at: 2014-07-01

Wavelet Kernel Based on Identification for Nonlinear Hybrid Systems

10.11591/ijeecs.v12.i7.pp5235-5243
Hamid Nourisola
This paper presents a new method based on wavelet for a class of nonlinear hybrid systems identification. Hybrid systems identification is composed of two problems; estimate the discrete modes or switch among the system modes and estimate continues submodels. In this paper, we assumed that haven’t any prior knowledge about data classification and submodels identification. Also the combining of feature vector selection algorithm and wavelet are used in subspace learning and support vector machine as a classifier. The results indicate that the error of using the wavelet in subspace learning process becomes low. In addition, the proposed method is convergent and has an acceptable response in presence of high-power noise.
Volume: 12
Issue: 7
Page: 5235-5243
Publish at: 2014-07-01

A Novel SSR Mitigation Method Based on GCSC in DFIG with Series Connected Compensator

10.11591/ijeecs.v12.i7.pp5022-5036
Zakieldeen Elhassan , Li Yang , Tang Yi
This paper presents a novel study for SSR mitigating in the wind power systems based on DFIG using GCSC (Gate controlled series capacitor). The GCSC is composed of three pairs of anti-parallel GTO Thyristors (Gate Turn- off) connected in parallel with a fixed capacitor. The GCSC is applied to reduce inrush current in capacitor compensator during the transient operation by executing a proper firing angle control of thyristor gates. In order to realize SSR oscillation when the transient operation occurred, the DFIG turbine is connected through the shaft turbine model. The simulation results shown that the GCSC device is suitable and reasonable for suppressing SSR caused by torsional interaction (TI) and torque amplification (TA) and also damping the subsynchronous oscillation as well. The transient simulations have been carried out using PSCAD/EMTDC program to demonstrate the capability of the GCSC device in mitigating SSR.
Volume: 12
Issue: 7
Page: 5022-5036
Publish at: 2014-07-01

Research on Operating Condition Effect on the Shock Pulse Method

10.11591/ijeecs.v12.i7.pp5392-5398
Ruifeng Zhang , Jianshe Kang , Lishan Hao , Xinghui Zhang , Hongzhi Teng , Haiping Li
Rolling bearings are one of the most widely used elements in industrial applications. Shock pulse method (SPM) has proven successfully as a diagnostic tool in determining bearing health. On the basis of illustrating the principle of SPM, this paper mainly concentrates on investigating the effect of different operating conditions on SPM. The shock pulse signals are derived from the wind turbine gearbox test rig by SPM instrument. Through comparing the slope of dB values when the rotating speed or load changes, effect of operating conditions on SPM is analyzed. The analysis results show that SPM is more sensitive to the rotating speed in contrast with the load.
Volume: 12
Issue: 7
Page: 5392-5398
Publish at: 2014-07-01

Optimal Feedback Control of Vehicle Vibration with Eight Degrees of Freedom

10.11591/ijeecs.v12.i7.pp5217-5224
Ali Hemati , Mehdi Tajdari , Ahmadreza Khoogar
In this paper the unfavorable body vibration of vehicles is compensated using direct feedback signals in an optimized manner. The parameter - optimization problem was gained through the second method of Liapunov. Moving vehicles bear unfavorable body vibration, especially in bumpy roads. Therefore, active control of this vibration seems attractive. Vertical vibration of the vehicle affects the driver's performance. In this paper an eight degrees of freedom dynamic vibration model of a general vehicle are developed through the designation of a closed-loop control system. A control system has been designed with efficient response which computes the feedback gains using the second method of Liapunov and it has been proven that appropriate comparison is obtained with this controller.
Volume: 12
Issue: 7
Page: 5217-5224
Publish at: 2014-07-01

Construction of Geological Knowledge-based Systems of Railway Route Selection

10.11591/ijeecs.v12.i7.pp5575-5584
Lv Xikui , Zhou Xiaoping , He Bin
According to the diversity of geological conditions involved in railway location design, different types of geological objects were classified and indexed, and proposed the modeling method based on multiple sub-bases. It used the computer's internal and external representation in geological knowledge representation. In computer external, it used object-oriented class-rules knowledge representation model, added credibility to the object-oriented knowledge representation model, and then achieved fuzzy representation of knowledge. In order to achieve visual representation of external knowledge representation, text, images and three-dimensional virtual reality technology were used. According to the ambiguity of geological knowledge, it realized uncertainty reasoning of the part based on rule condition and conclusions.
Volume: 12
Issue: 7
Page: 5575-5584
Publish at: 2014-07-01

Improved Information Systems Model for Bangladesh

10.11591/ijeecs.v12.i7.pp4893-4899
Jahangir Alam S.M. , Hu Guoqing , M. Rabiul Alam , Md. Golam Kibria , Md. Abdul Malek
In the era of globalization, implementation of e-Government (e-Gov) is very crucial because it modernizes the public and private sector for the well being of people. To build the electronic based automatic governance for improving the quality of public services is the prime measure for implementation of e-Governance in Bangladesh. Interoperability is a key issue in implementing an e-Government system. To create a general platform for sharing and exchanging information among different institutions is essential for interoperability. Grid Computing based service could be a solution for resource sharing and interoperability of e-Gov systems.  It is important to prepare standard policies and guidelines for e-Governance so that the desired expectations of interoperability between central and local government agencies can be achieved. Bangladesh government needs a specific policy which will deal with interoperability and ensure transparency and accountability in the Grid Computing Model. 
Volume: 12
Issue: 7
Page: 4893-4899
Publish at: 2014-07-01

A Harmonic Analysis Method Based on Harris Window for Digital Substation

10.11591/ijeecs.v12.i7.pp5078-5085
Luo Hanwu
Accurate and efficient harmonics detection is an important premise and basis for controlling the harmonics. The sampling frequency of the grid voltage and current in digital substation normally must be kept constantly as required by the standard of IEC61850, thus the asynchronous sampling caused by the fluctuating grid frequency and this constant sampling frequency will result in spectral leakage and aliasing which would affect the accuracy of harmonic analysis. In this paper, a double-spectrum-line interpolation Fast Fourier Transform approach based on multi-term Harris window for grid frequency and harmonic measurement was proposed, and the simple and practical adjustment formulas for the frequency, amplitude and phase angle were derived by curve fitting. The correctness and effectiveness of the proposed method were validated by simulation and field test.
Volume: 12
Issue: 7
Page: 5078-5085
Publish at: 2014-07-01

A Survey on Clustering Routing Protocols Based on PSO in WSN

10.11591/ijeecs.v12.i7.pp5484-5490
Enyan Sun
LEACH is a traditional clustering routing protocol in wireless sensor network. When selecting the cluster head, LEACH does not consider sensor nodes’ energy and position information. It leads to uneven the distribution of cluster heads and uneven energy consumption of sensor nodes. Clustering routing protocols which are based on particle swarm optimization have been proposed to improve the performance of clustering routing protocols. This paper introduces and classifies the clustering routing protocols which are based on PSO and points the future direction. 
Volume: 12
Issue: 7
Page: 5484-5490
Publish at: 2014-07-01
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