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25,002 Article Results

Cost Allocation of Transmission Losses in Electric Market Mechanism

10.12928/telkomnika.v10i2.779
Hermagasantos; State Polytechnic of Bandung (POLBAN) Zein , Erwin; Unversitas Muhammadiyah Jakarta Dermawan
 This paper proposes a new method to calculate cost allocation of transmission losses based on a certain price of energy. A mathematic model is developed by manipulating of the network equation to separate losses. This model uses complex power injection and, does not use approximations and assumptions in determining the cost allocation of losses. The calculation begins from the results of load flow calculation and it is continued to calculate power distribution from a generator to every load and line. Finally, the separating of losses and cost allocation of losses are calculated. The proposed method is easy to be understood and applied. An illustration results on IEEE 14-bus system show that the method is consistent with expectancies and slightly different from several referenced methods. 
Volume: 10
Issue: 2
Page: 211-218
Publish at: 2012-06-01

A New Control and Design of PEM Fuel Cell Powered Air Diffused Aeration System

10.12928/telkomnika.v10i2.798
Doaa M.; Electronics Research Institute Atia , Faten H.; Electronics Research Institute Fahmy , Ninet M.; Electronics Research Institute Ahmed , Hassen T.; Cairo University Dorrah
Aeration of water by using PEM fuel cell power is not only a new application of the renewable energy, but also, it provides an affordable method to promote biodiversity in stagnant ponds and lakes. This paper presents a new design and control of PEM fuel cell powered by diffused air aeration system for a shrimp farm in Mersa Matruh in Egypt. Also Artificial intelligence (AI) techniques control is used to control the fuel cell output power by controlling input gases flow rate. Moreover the mathematical modeling and simulation of PEM fuel cell is introduced. A comparison study is applied between the performance of fuzzy logic control (FLC) and neural network control (NNC). The results show the effectiveness of NNC over FLC.
Volume: 10
Issue: 2
Page: 291-302
Publish at: 2012-06-01

Crosstalk Improvement of Polymer in Glass Thermo-Optical Multimode Interference Switch

10.12928/telkomnika.v10i2.813
N. Samdin; Universiti Teknologi Malaysia N. Samdin , M. Yaacob; Universiti Teknologi Malaysia M. Yaacob , M.H. Ibrahim; Universiti Teknologi Malaysia M.H. Ibrahim , A.B. Mohammad; Universiti Teknologi Malaysia A.B. Mohammad , N.M. Kassim; Universiti Teknologi Malaysia N.M. Kassim
A new structural design of combined variable optical attenuator (VOA) and optical switch has been proposed in this paper. The design is based on the multimode interference (MMI) architecture and it has been demonstrated for crosstalk improvement of optical switch. The device operates by manipulating thermo-optic (TO) effect that naturally existed in all optical waveguide material. By applying a polymer on glass material platform, the optimized VOA with optical attenuation of 21.52 dB has been achieved with applied power of 36.4 mW. The simulation result shows that the VOA helps to achieve significant improvements of optical switch performance particularly in crosstalk reduction up to 89.66%. 
Volume: 10
Issue: 2
Page: 371-378
Publish at: 2012-06-01

Comparison of Predictive Models for Photovoltaic Module Performance under Tropical Climate

10.12928/telkomnika.v10i2.783
Koumi Ngoh; University of Yaoundé I, University Institute of Technology Douala Simon , Njomo; University of Yaoundé I Donatien , Moungnutou Mfetoum; National Advanced School of Engineering Inoussah
This paper examines four models which are used to estimate the performance of photovoltaic (PV) modules when the irradiances and PV cell temperatures are known. The models were simulated and the operating temperature and irradiance dependence of PV electrical efficiency and power output were studied. The models accuracy was obtained by comparing the models and the measurements of maximum power for a polycrystalline typical MXS 60 PV module under tropical climate. The evaluated models for estimating the maximum power are the single diode, the Photovoltaic geographical information system (PVGIS), the Borowy and Salameh, and the Hatziargyriou model. The analysis of the error curves shows that the single diode and Hatziargyriou model have better accuracy. The PVGIS and Borowy approach are not appropriate as the module performance prediction in Sudanese sahelian climate.
Volume: 10
Issue: 2
Page: 245-256
Publish at: 2012-06-01

Blood Vessel Enhancement and Segmentation for Screening of Diabetic Retinopathy

10.12928/telkomnika.v10i2.802
M. Usman; Bahria University Akram , Ibaa; Bahria University Jamal , Anam; Bahria University Tariq
Diabetic retinopathy is an eye disease caused by the increase of insulin in blood and it is one of the main cuases of blindness in idusterlized countries. It is a progressive disease and needs an early detection and treatment. Vascular pattern of human retina helps the ophthalmologists in automated screening and diagnosis of diabetic retinopathy. In this article, we present a method for vascular pattern ehnacement and segmentation. We present an automated system which uses wavelets to enhance the vascular pattern and then it applies a piecewise threshold probing and adaptive thresholding for vessel localization and segmentation respectively. The method is evaluated and tested using publicly available retinal databases and we further compare our method with already proposed techniques. 
Volume: 10
Issue: 2
Page: 327-334
Publish at: 2012-06-01

Design of FPGA Based Neural Network Controller for Earth Station Power System

10.12928/telkomnika.v10i2.796
Hanaa T.; Electronics Research Institute El-Madany , Faten H.; Electronics Research Institute Fahmy , Ninet M. A.; Electronics Research Institute El-Rahman , Hassen T.; Cairo University Dorrah
Automation of generating hardware description language code of neural networks models can highly decrease time of implementation those networks into a digital devices, thus significant money savings. To implement the neural network into hardware design, it is required to translate generated model into device structure. VHDL language is used to describe those networks into hardware. VHDL code has been proposed to implement ANNs as well as to present simulation results with floating point arithmetic of the earth station and the satellite power systems using ModelSim® PE 6.6 simulator tool. Integration between MATLAB® and VHDL is used to save execution time of computation. The results shows that a good agreement between MATLAB and VHDL and a fast and flexible feed forward NN which is capable of dealing with floating point arithmetic operations; minimum number of CLB slices; and good speed of performance. FPGA synthesis results are obtained with view RTL schematic and technology schematic from Xilinix tool. Minimum number of utilized resources is obtained by using Xilinix VERTIX5. 
Volume: 10
Issue: 2
Page: 281-290
Publish at: 2012-06-01

Optimal Power Flow Solution of the Algerian Electrical Network using Differential Evolution Algorithm

10.12928/telkomnika.v10i2.778
Linda; Setif University Slimani , Tarek; Setif University Bouktir
This paper presents solution of optimal power flow (OPF) problem of a power system via differential evolution (DE) algorithm. The purpose of an electric power system is to deliver real power to the greatest number of users at the lowest possible cost all the time. So the objective is to minimize the total fuel cost of the generating units and also maintaining an acceptable system performance in terms of limits on generator reactive power outputs, bus voltages, static VAR compensator (SVC) parameters and overload in transmission lines. CPU times can be reduced by decomposing the problem in two subproblems, the first subproblem minimize the fuel cost of generation and the second subproblem is a reactive power dispatch so optimum bus voltages can be determined and reduce the losses by controlling tap changes of the transformers and the static VAR compensators (SVC). To verify the proposed approach and for comparison purposes, we perform simulations on the Algerian network with 114 buses, 175 branches (lines and transformers) and 15 generators. The obtained results indicate that DE is an easy to use, fast, robust and powerful optimization technique compared to the other global optimization methods such as PSO and GA.
Volume: 10
Issue: 2
Page: 199-210
Publish at: 2012-06-01

Optimization and Feasibility Analysis of Satellite Earth Station Power System Using Homer

10.12928/telkomnika.v10i2.812
Hanaa T.; Electronics Research Institute El-Madany , Faten H.; Electronics Research Institute Fahmy , Ninet M. A.; Electronics Research Institute El-Rahman , Hassen T.; Cairo University Dorrah
Satellite earth stations which located in remote areas are one of many applications powered by the renewable energy sources. Ground system consists of ground station and control centers working together to support the spacecraft and the data user. Earth station consists of major subsystems, transmitter, receiver, antenna, tracking equipment, terrestrial interface equipment and power supply. Power subsystem is an important part that required for supplying the earth station with electrical power to continue communicating with its remote sensing satellite. This paper deals with simulation and optimal sizing of earth station power system using HOMER software. A combination of two energy sources (solar, and wind) to provide a continuous electric power production is used to determine the optimum system operation. Three system configurations are compared with respect to the total net present cost (NPC) and levelized cost of energy (COE). Also, economical study will be analyzed for energy demand and sensitivity analysis will be performed.
Volume: 10
Issue: 2
Page: 359-370
Publish at: 2012-06-01

Modeling and Validation of the Dynamic Host Configuration Protocol with Colored Petri Nets

https://ijece.iaescore.com/index.php/IJECE/article/view/5346
Farhad Soleimanian Gharehchopogh , Reza Soufizadeh
Petri Networks with a graphical language are based on mathematical logic which have many uses and have capability for modeling and validation of distributed systems and concurrent applications. Colored Petri Networks (CPNs) are a type of Petri Network models that are used in modeling of systems which contain discrete and scattered events. In general, CPNs are used to evaluate system performance and demonstrate the correctness of systems. Dynamic Host Configuration Protocol (DHCP) is one of the main systems of protocols special for servers that are used for dynamic allocation of IP to the network computers (clients). In this paper, we highlight to analyze the correctness and authenticity of DHCPs with the use of CPNs with using the CPN Tools and to prove the accuracy of our protocol's performance.DOI:http://dx.doi.org/10.11591/ijece.v2i3.488
Volume: 2
Issue: 3
Page: 437-440
Publish at: 2012-05-29

Artificial Neural Expert Computing Models for Determining Shelf Life of Processed Cheese

https://ijece.iaescore.com/index.php/IJECE/article/view/5327
SUMIT GOYAL , Gyanendra Kumar Goyal
Time-delay single and multi layer models were developed for predicting shelf life of processed cheese stored at 30oC. Processed cheese is very nutritious dairy product, rich in milk proteins and milk fat. For developing computational neuroscience models,experimental data relating to body & texture, aroma & flavour, moisture, free fatty acids were taken as input variables, while sensory score as output variable. Mean Square Error, Root Mean Square Error, Coefficient of determination and Nash - Sutcliffo Coefficient were applied in order to compare the prediction performance of the developed computational models. The results of the study established excellent correlation between experimental data and the predicted values, with a high determination coefficient. From the study it was concluded that artificial neural expert time-delay models are good for predicting the shelf life of processed cheese.DOI:http://dx.doi.org/10.11591/ijece.v2i3.353
Volume: 2
Issue: 3
Page: 333-338
Publish at: 2012-05-01

A Design of Gain Boosted Error Amplifier Applied to PWM Control

https://ijeecs.iaescore.com/index.php/IJEECS/article/view/2237
Yu Shi-Hua , Wang Kai-Yu , Wei Shu-Ping , Wang Xiao-Feng , Yang Ming-Jian
A high gain, wide common-mode and high swing error amplifier is proposed. It can be applied to a PWM control chip. The error amplifier adopts folded cascode structure with gain boosted. This chip is simulated and fabricated in the CSMC 0.5μm CMOS. The result shows that the error amplifier has the DC gain of 141.11dB, the common-mode input range of 0~3.87v and the output swing of 0.11~4.80v. These meet the requirements of engineering applications and can realize stable system output. DOI: http://dx.doi.org/10.11591/telkomnika.v11i5.2461
Volume: 11
Issue: 5
Page: 2365-2370
Publish at: 2012-05-01

DSTATCOM Application for Mitigation of Voltage Sag Caused by Dynamic Loads in Autonomous Systems

https://ijpeds.iaescore.com/index.php/IJPEDS/article/view/4901
Ambarnath Banerji , Dr. Sujit K. Biswas , Bhim Singh
This paper presents the application of distribution static compensator (DSTATCOM) for mitigating the frequently occurring problems of voltage dips in autonomous systems. Consumer loads are experiencing proliferation of induction motors. The starting of induction motors draws large current causing voltage sag (dip). Autonomous Power system is comparatively less stiff than the grid connected system. Large starting current, causing objectionable voltage drop, is critical for an autonomous system. DSTATCOM can be effectively used to redeem this power quality problem. An asynchronous generator with a motor load having a DSTATCOM connected in shunt is simulated on a MATLAB platform using Simulink and Power System Block set. The simulation establishes the capability of DSTATCOM to mitigate the voltage dip problem for an autonomous system.DOI: http://dx.doi.org/10.11591/ijpeds.v2i2.320  
Volume: 2
Issue: 2
Page: 232-240
Publish at: 2012-04-30

Increasing the Accuracy of Detection and Recognition in Visual Surveillance

https://ijece.iaescore.com/index.php/IJECE/article/view/5338
Ali Bazmi , karim Faez
Visual surveillance has two major steps of detecting and recognizing moving objects. In the detection stage, moving objects must be detected as quickly and accurately as possible and the influence of environmental light changes and waving trees should be reduced. In this research a block-based method is introduced in HSV color space in the detection stage. This method did not scan all the pixels of the frame and acted well in situations like sudden light changes. A powerful pattern recognition system should have powerful feature extraction and classification. Note that, feature extraction in gray level or RGB color space has problems such as environmental light changes, adding noise or changes in contrast and sharpness of images, which lead to weak classification. So the HSV color space was used. Here, Block-based Improved Center Symmetric Local Binary Pattern is introduced for feature extraction. In each component of the HSV color space, information of highlight areas in the image such as edge, shape and some texture was extracted. The histogram was calculated in two-level blocks and Support Vector Machine was used for classifying into vehicles, motorcycles and pedestrians. The obtained results in increasing the detection accuracy and decreasing the spent time were satisfactory.DOI:http://dx.doi.org/10.11591/ijece.v2i3.337
Volume: 2
Issue: 3
Page: 395-404
Publish at: 2012-04-30

Optimal Location of FACTS Device on Enhancing System Security

https://ijece.iaescore.com/index.php/IJECE/article/view/5321
Prakash Gajanan Burade , Jagdish Helonde
In this paper  a Unified Power Flow Controller (UPFC) is a FACTS device that can be control the power flow in transmission line by injecting active and reactive in voltage components in series with the lines.The proposed methodologies are based on the use of line loading security Performance Index (sensitivity factors have been suggested in this paper for optimal placement of UPFC.This methods are computationally efficient PI sensitivity   factors have been obtained with respect to change in two of the UPFC parameters viz., magnitude and phase angle of the injected voltage in the lines. The proposed methodologies are tested validated for locating UPFC in IEEE 30-bus system.ACO based Optimal Power Flow (OPF) formulation has been suggested to determine the optimal PI values, after placement of UPFC based on the proposed sensitivity factors. Both AC and DC power flow approximations have been used to define the sensitivity factors and their results have been compared on IEEE 30-bus system.DOI:http://dx.doi.org/10.11591/ijece.v2i3.250
Volume: 2
Issue: 3
Page: 309-316
Publish at: 2012-04-30

On Line Stator Resistance Tuning of DTC Control CSI Fed IM Drives

https://ijpeds.iaescore.com/index.php/IJPEDS/article/view/4900
N. Panner selvam , M. Arul Prasanna , I. Gerald Christopher raj
Current source inverter (CSI) fed drives are employed in high power applications. The conventional CSI drives suffer from drawbacks such as harmonic resonance, unstable operation at low speed ranges, and torque pulsation. CSI fed drives with Direct Torque Control (DTC) has drawn the attention of the motor drives designers because its implementation requires no position sensor. Crucial to the success of this scheme is the estimation of electromagnetic torque and stator flux linkages using the measured stator voltages and currents. The estimation is dependent only on one machine parameter, stator resistance. The variation of the stator resistance, deteriorates the performance of the drive by introducing errors in the estimated flux linkage’s magnitude and its position and hence in the electromagnetic torque. Resistance change also skews the torque linearity thus making the motor drive a less than ideal torque amplifier. Parameter compensation using stator current phasor error has been proposed in literature. To obtain the stator current phasor error, the stator current reference is required which is not usually available in direct torque control schemes. An analytical derivation of the stator current phasor reference is derived systematically from the reference electromagnetic torque and flux linkages. The error between the stator current phasor reference and its measured value is a measure of the stator resistance variation from its set value. For the first time, it is demonstrated in this paper that DTC motor drive system can become unstable when the set value of the stator resistance in the controller is higher than the stator resistance in the machine. Hence parameter adaptation is not only important for torque linearity but also for stability of the system is shown in this paper.DOI: http://dx.doi.org/10.11591/ijpeds.v2i2.332
Volume: 2
Issue: 2
Page: 225-231
Publish at: 2012-04-30
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