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23,598 Article Results

Determining the Excitation Voltage of Axial Flux Wound Rotor Synchronous Generator

10.12928/telkomnika.v11i2.926
Abdul; Universitas Indonesia Multi , Iwa; Universitas Indonesia Garniwa
The axial flux wound rotor generator has field winding that must be connected to a dc voltage source. By varying the excitation voltage, its electric performance might  be controlled to meet the need of a load voltage attached to its terminal. The designed generator is small-scale capacity which has 1 kW, 380 V and 750 rpm. The generator has a single double-sided slotted wound stator sandwiched between twin rotor. The effect of excitation voltage changes on its performance can be seen from the result of calculations using the given equations. The calculation results reveal electric quantities suited with respect to performance of the machine. If the voltages increase, the losses will decrease; but higher the excitation voltage, higher the efficiency and the terminal voltage. It has been found out that for the excitation voltage11 V, the efficiency and the terminal voltage are 85.12 % and 380V respectively.
Volume: 11
Issue: 2
Page: 277-284
Publish at: 2013-06-01

Rotating Cantilever Beam Dynamic Strain Measurement and Analysis Based on FBG

https://ijeecs.iaescore.com/index.php/IJEECS/article/view/2364
Jiang Xi-Xin
The main form of machine’s working principle is rotation. The mechanical properties of rotating component is significant importance to improve the machine’s reliability. In the measurement, the difficult thing is to transmit signals form sensors on a rotor to a stationary part . In this paper, using the FBG’s(Fibre Bragg Gauge)  properties of wireless transmission, author measure the local strains of rotating cantilever beam cantilever by utilizing the strain principle gauge FBG(Fibre Bragg Gauge) and the rotary signal transmit equipment,. The result of analysis showed that rotating cantilever have complicate dynamic phenomenon, dynamic strain not only related to speed but also related to fluid action, the dynamic stiffing phenomenon were observe in the same time. Finally, author offer an improved insight into a strain measurement technique for a rotating mechanical system. The research work could provide an effective way for measuring rotating component’s mechanical properties. DOI: http://dx.doi.org/10.11591/telkomnika.v11i6.2690
Volume: 11
Issue: 6
Page: 3327-3332
Publish at: 2013-06-01

Power Quality Signal De-noising with Sub band Adaptive Algorithm

10.12928/telkomnika.v11i2.936
Yingjun; Huaiyin Institute of Technology, Southeast University Sang , Yuanyuan; Huaiyin Institute of Technology Fan
A new level-dependent sub band adaptive noise reduction algorithm based on wavelet transform is proposed in order to improve the effect of power quality signal de-noising for power quality monitoring system. This threshold algorithm has two adjustable parameters to adjust the threshold both fine and coarsely, and the optimal parameters are determined by BP neural networks algorithm. Power disturbance data is referred to actual power disturbance data at IEEE open source and applied for test. The test results indicate that the proposed algorithm could denoise the different kind of power disturbances effectively, and the signal noise ratio is improved further with a smaller mean square error.
Volume: 11
Issue: 2
Page: 347-354
Publish at: 2013-06-01

Improved Based on "Self-Adaptive Turning Rate" Model Algorithm

https://ijeecs.iaescore.com/index.php/IJEECS/article/view/2313
Xiuling He , Yan Shi , Jiang Yunfang
For tracking the object with tracking nonlinear, high maneuvering target，traditional interactive multiple model self-adaptive filter algorithm was usually adopted．The turning rate estimate was very important. However，the performance of turning rate algorithm was not so satisfactory in the  model．Thus，a new the average value turning rate algorithm based on self-adaptive turning model was proposed．Aiming at additional device for turning rate estimation turning model, the parameters α and β were introduced to adjust the roughness of turning rate．Aiming at target constant turning movement and orthogonal turning rate unequal, estimates, turning rate was used the average value model to reduce the noise and error influence. Simulation results showed that the proposed algorithm was more suitable for the objects with Nonlinear, high maneuvering target tracking and could remarkably reduce the sample，and thus achieve much better tracking performance. DOI: http://dx.doi.org/10.11591/telkomnika.v11i6.2602
Volume: 11
Issue: 6
Page: 2968-2975
Publish at: 2013-06-01

Implementation of Waste Battery Energy Collection System

https://ijeecs.iaescore.com/index.php/IJEECS/article/view/2357
Li Chao , Yi Bo-nian
In this energy collection system, it uses Boost and Buck circuits. If the input voltage is too low, low power supply chip will be active ,making the charging voltage at an appropriate range. In order to measure the input voltage, output voltage and the current, high-precision chips are used, cooperated with 32-bits-high-speed CPU to make sure the output voltage stable. This system has a perfect over-current ,over-voltage protection function. The system uses the high efficient switch power supply. DOI: http://dx.doi.org/10.11591/telkomnika.v11i6.2683
Volume: 11
Issue: 6
Page: 3279-3284
Publish at: 2013-06-01

Efficient Content Location Using Semantic Small World in Peer-to-Peer Networks

10.12928/telkomnika.v11i2.909
Yong; University of Posts and Telecommunications Chen , Wei-zhong; University of Posts and Telecommunications Xiao , Huan-lin; University of Posts and Telecommunications Liu , Long-zhao; University of Posts and Telecommunications Sun
        Locating content in unstructured peer-to-peer networks is a challenging problem. This paper presents a novel semantic small world resource search mechanism to address the problem. By using vector space model to compute the semantic relevance and applying small world properties such as low average hop distance and high clustering coefficient to construct a cluster overlay. In semantic small world system, the search mechanism is divided into two parts, searching at cluster and outside cluster through inner link and short link, so that it can achieve the incremental research. It significantly reduces the average path length and query cost. Meanwhile, the simulation results show that semantic small world scheme outperforms K-random walks and flooding scheme than higher query hit rate and lower query latency.
Volume: 11
Issue: 2
Page: 223-230
Publish at: 2013-06-01

Optimized Passive Coupling Control for Biped Robot

https://ijeecs.iaescore.com/index.php/IJEECS/article/view/2323
Lipeng YUAN , Amur Al Yahmedi , Liming Yuan
A popular hypothesis regarding legged locomotion is that humans and other large animals walk and run in a manner that minimizes the metabolic energy expenditure for locomotion.  Here, we just consider the walking gait patterns. And we presented a hybrid model for a passive 2D walker with knees and point feet. The dynamics of this model were fully derived analytically. We have also proposed optimized virtual passive and virtual coupling control laws. This is also a simple and effective gait-generation method based on this kneed walker model, which imitates the energy behavior in every walking cycle. The control strategy is formed by taking into account the features of mechanical energy dissipation and restoration. Following the proposed method, we use computer optimization to find which gaits are indeed energetically optimal for this model. And we also prove some walking rules maybe true by the results of simulations. DOI: http://dx.doi.org/10.11591/telkomnika.v11i6.2612
Volume: 11
Issue: 6
Page: 3044-3052
Publish at: 2013-06-01

Integrated Control of Nonlinear Vehicle Stability

https://ijeecs.iaescore.com/index.php/IJEECS/article/view/2320
Jie Tian , Yaqin Wang , Ning Chen
A novel vehicle stability control method integrated direct yaw moment control (DYC) with active front steering (AFS) is presented in this paper. By the phase plane of sideslip angle and sideslip angular velocity, vehicle stable region is determined. When the vehicle is outside the stable region, DYC controller is firstly used to produce proper direct yaw moment, which can make the vehicle back to the stable region. Then AFS controller of sliding mode variable structure is constructed and used to control the front steering angle of the actual vehicle, so that the sideslip angle and yaw rate of the actual vehicle model can track those of the reference vehicle model. Computer simulations are carried out on a 2-DOF nonlinear vehicle model to investigate the effectiveness of the proposed method. And the simulation results show that the influence of the proposed method on enhancing vehicle stability is significant. DOI: http://dx.doi.org/10.11591/telkomnika.v11i6.2609
Volume: 11
Issue: 6
Page: 3020-3027
Publish at: 2013-06-01

On the Security of NMAC and Its Variants

10.12928/telkomnika.v11i2.940
Fanbao; National University of Defense Technology Liu , Changxiang; Beijing University of Technology Shen , Tao; (NUDT) National University of Defense Technology Xie , Dengguo; Chinese Academy of Sciences Feng
Based on the three earlier MAC (Message Authentication Code) construction approaches, we propose and analyze some variants of NMAC. We propose  some key recovery attacks to  these  NMAC  variants, for  example, we can  recover  the  equivalent  inner  key  of NMAC  in  about O(2n/2) MAC  operations, in  a related key  setting. We  propose  NMAC-E, a  variant of NMAC  with  secret  envelop,  to  achieve  more  process  efficiency  and  no  loss  of security, which needs only one call to the  underlying hash  function, instead of two invocations in HMAC.
Volume: 11
Issue: 2
Page: 381-392
Publish at: 2013-06-01

An Improved Image Contrast Assessment Method

10.12928/telkomnika.v11i2.930
Yuanyuan; Huaiyin Institute of Technology Fan , Yingjun; Huaiyin Institute of Technology Sang , Guang Hu; Huaiyin Institute of Technology Guang Hu , Zaijin; Huaiyin Institute of Technology Zhou , Yunrong; Huaiyin Institute of Technology Hao
Contrast is an important factor affecting the image quality. In order to overcome the problems of local band-limited contrast, a novel image contrast assessment method based on the property of HVS is proposed. Firstly, the image by low-pass filter is performed fast wavelet decomposition. Secondly, all levels of band-pass filtered image and its corresponding low-pass filtered image are obtained by processing wavelet coefficients. Thirdly, local band-limited contrast is calculated, and the local band-limited contrast entropy is calculated according to the definition of entropy. Finally, the contrast entropy of image is obtained by averaging the local band-limited contrast entropy weighed using CSF coefficient. The experiment results show that the best contrast image can be accurately identified in the sequence images obtained by adjusting the exposure time and stretching gray respectively, the assessment results accord with human visual characteristics and make up the lack of local band-limited contrast.
Volume: 11
Issue: 2
Page: 305-312
Publish at: 2013-06-01

Research of Plant-Leaves Classification Algorithm Based on Supervised LLE

https://ijeecs.iaescore.com/index.php/IJEECS/article/view/2355
Yan Qing , Liang Dong , Zhang Jingjing
A new supervised LLE method based on the fisher projection was proposed in this paper, and combined it with a new classification algorithm based on manifold learning to realize the recognition of the plant leaves. Firstly，the method utilizes the Fisher projection distance to replace the sample's geodesic distance, and a new supervised LLE algorithm is obtained .Then, a classification algorithm which uses the manifold reconstruction error to distinguish the sample classification directly is adopted. This algorithm can utilize the category information better，and improve recognition rate effectively. At the same time, it has the advantage of the easily parameter estimation. The experimental results based on the real-world plant leaf databases shows its average accuracy of recognition was up to 95.17%. DOI: http://dx.doi.org/10.11591/telkomnika.v11i6.2680
Volume: 11
Issue: 6
Page: 3265-3270
Publish at: 2013-06-01

Design and Development of Curious Jojo©: A Go-Green 3D Game on Android

https://ijeecs.iaescore.com/index.php/IJEECS/article/view/2335
Juliana A. Abubakar , Ariffin Abd. Mutalib , Dendi Permadi
Various campaigns such as ‘Save the Earth’, ‘Earth Hour’, and ‘Reduce, Reuse, Recycle’ are held to create environmental awareness among the general public. The effort is seen endlessly using any means of presentation and communication medium in order to ensure the intended message reach its audience. Meanwhile, the availability of mobile devices and the advent of natural user interfaces have simplified the interaction in games so that it is intuitive for vast audience at different abilities. Hence, this would possibly provide wider audience an engaging experience while playing games and at the same time absorbing the intended message. This article describes the process of designing and developing a go-green tridimensional (3D) game on a mobile platform. It also discusses educational benefits of games and how the concept of environmental awareness is integrated into the game play in order to educate the general public especially the young ones about their social roles. Initial results on performance assessment reveal that the functionality of interactive elements in the game is excellent and young ones did not have difficulties in playing the game. Future work will focus on how 3D mobile games facilitate informal learning process such as inculcating environmental awareness to the general public. DOI: http://dx.doi.org/10.11591/telkomnika.v11i6.2657
Volume: 11
Issue: 6
Page: 3123-3129
Publish at: 2013-06-01

Design of Instrument Control System Based on LabVIEW

https://ijeecs.iaescore.com/index.php/IJEECS/article/view/2378
Jiang Chao , Xu Wu-bin , Li Bing
In order to solve the problems such as poor expansion, long development cycle of instrument control system developed by traditional programming language, using VISA module based on LabVIEW platform was introduced. This paper presented a simplicity, intuitive instrument control system of pneumatic measuring instrument, which was accomplished with graphical language LabVIEW. The system could also complete the text data output. It was improved that the system based on LabVIEW achieved instrument control efficiently, openly, with operating conveniently and good human-machine interface. DOI: http://dx.doi.org/10.11591/telkomnika.v11i6.2719
Volume: 11
Issue: 6
Page: 3427-3432
Publish at: 2013-06-01

Monte-Carlo SURE for Choosing Regularization Parameters in Image Deblurring

https://ijeecs.iaescore.com/index.php/IJEECS/article/view/2352
Yubing Han , Kelan Wang , Mengna Xu
Parameter choice is crucial to regularization-based image deblurring. In this paper, a Monte Carlo method is used to approximate the optimal regularization parameter in the sense of Stein’s unbiased risk estimate (SURE) which has been applied to image deblurring. The proposed algorithm is suitable for the exact deblurring functions as well as those of not being expressed analytically. We justify our claims by presenting experimental results for SURE-based optimization with two different regularization algorithms of Tikhonov and total variation regularization. Experiment results show the validity of the proposed algorithm, which has similar performance with the minimum MSE. DOI: http://dx.doi.org/10.11591/telkomnika.v11i6.2675
Volume: 11
Issue: 6
Page: 3242-3250
Publish at: 2013-06-01

Nine-Phase Induction Motor Dynamic Model Based On 3x9 Transformation Matrix

10.12928/telkomnika.v11i2.919
Arman; Sepuluh Nopember Institute of Technology (ITS), Polytechnics Institute of Surabaya (PENS) Jaya , Soebagio; Sepuluh Nopember Institute of Technology (ITS) Soebagio , Mauridhi Hery; Sepuluh Nopember Institute of Technology (ITS) Purnomo
Analysis of the dynamic model nine-phase induction motor becomes difficult because based on a 9x9 matrix and a circuit of magnetically coupled transformer. In order to gain the qdn dynamic model of the nine-phase induction motors in easy, simple, quick and consistent way, the motor analysis will  based on 3x9 transformation matrix and the equivalent circuit T model. The 3x9 transformation matrix qdn is substituted into the equation in  form abc so that the matrix equation of qdn is obtained. Then qdn equation results a similar qd equivalent circuit, which has different methods n that is, based the circuit of magnetically coupled transformer. Simulation results show that the dynamic characteristics of 9-phase induction motor based on the T model and magnetically coupled circuit have similar torque and speed dynamic response.
Volume: 11
Issue: 2
Page: 265-276
Publish at: 2013-06-01
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