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24,092 Article Results

The Combined Forecasting Model of Discrete Verhulst-BP Neural Network Based on Linear Time-Varying

https://ijeecs.iaescore.com/index.php/IJEECS/article/view/3374
Shang Hongchao , Long Xia , He Tingjie
Firstly, this paper, aiming at the problem of errors produced by the transformation of differential equation directly into difference equation from traditional gray Verhulst model,through generating reciprocal for the original data sequence, constructs the discrete Vrhulst model based on linear time-varying(LTDVM model);And then we, taking the LTDVM predicted value as an input value and the original data as a mentor training value, put forward the combined forecasting model of discrete Verhulst-BP neural network based on linear time-varying. Meanwhile, in order to improve the training speed and agility and effectively avoid the saturation region of S-type function, this article normalized in advance the input data and mentor training values to better ensure the usefulness, self-learning ability and fault tolerance of the model. At last, we will study the cases to demonstrate that the model has high modeling and forecasting accuracy. DOI : http://dx.doi.org/10.11591/telkomnika.v12i4.4938
Volume: 12
Issue: 4
Page: 3224-3229
Publish at: 2014-04-01

Attack the Anycast Signature Scheme

https://ijeecs.iaescore.com/index.php/IJEECS/article/view/3371
Jinbin Zheng
Today, the internet is increasingly being considered to provide services, and not just in order to connect. As this view became more universal, the important factors of providing such services are reliability and availability of the services to meet the needs of a large number of users. Anycast is a communication mode in which the same address is assigned to a group of servers and the router will send the request to the ”best” server. Al-Ibrahim and Cerny proposed an authentication scheme of anycast communication. Their scheme is based on El-Gamal type signature scheme. We prove that their preferred scheme, which does not require interaction among the various signers, is insecure. DOI : http://dx.doi.org/10.11591/telkomnika.v12i4.4931
Volume: 12
Issue: 4
Page: 3200-3207
Publish at: 2014-04-01

Switching Surface Design for Nonlinear Systems: the Ship Dynamic Positioning

https://ijeecs.iaescore.com/index.php/IJEECS/article/view/3278
Diallo Thierno Mamadou Pathe , Hongsheng Li , Guangrong Bian
In this paper a design of the switching-surface for the nonlinear system is studied. The aim was to prove that with the linear matrix inequality the coefficients of the sliding surface can be determined optimally for the control law structure. The advantages of the use of the linear matrix inequality reside in the accurate determination of the coefficients of the sliding surface. The sliding mode control for dynamic positioning of the ship with our proposed switching-surface is done. The objective of this control was to make sure that the ship follows a predetermined track. The good trackings are observed from the simulation results which confirm the robustness of the control law obtained by our proposed switching-surface. DOI : http://dx.doi.org/10.11591/telkomnika.v12i4.4739
Volume: 12
Issue: 4
Page: 2439-2447
Publish at: 2014-04-01

Performance Analysis of Voltage Stability Against Sudden Load Changes in Voltage Controlled Inverters for Distributed Generation

10.11591/ijape.v3.i1.pp33-40
Arvind H. Kadam , Keerthi Unni , Sushil Thale
Distributed Generation (DG) is playing an important role in the field of electricity generation by being a viable alternative to the Centralized Power Generation (CPG). Although, distributed generation has many advantages, it has some issues in the fields of protection, power control, stability, islanding detection etc. Amongst all the issues, this paper attempts to highlight the issue of voltage stability under sudden changes in loading conditions in a distributed generation systems operating in stand-alone mode. Proper design and tuning of compensators for closed loop operation in DG systems can ensure voltage stability. As the load demand increases, the output voltage of DG usually dips for a short time owing to the weak (smaller capacity) nature of renewable sources, after which it returns to steady state. This fall in the voltage profile could prove to be harmful if the settling time is more. The simulation and hardware results illustrate that, accurate compensator design, is one of the key factor in maintaining the voltage stability in DG system. This paper explores the effect of proper compensator design in maintaining voltage stability of DG.
Volume: 3
Issue: 1
Page: 33-40
Publish at: 2014-04-01

Hardware-in-the-loop Simulation Platform of Photovoltaic Grid-Connected System

https://ijeecs.iaescore.com/index.php/IJEECS/article/view/3281
Lin FENG , Qing ZHONG , Nanhua YU , Kun WANG , Guojie LI , Kan CHEN
 The modeling and simulation of photovoltaic power generation system has become an important issue in the field of power generation. Research on the characteristics of photovoltaic (PV) grid-connected system by hardware-in-the-loop simulation could provide convenient experiment condition and accurate result. This article designs a photovoltaic grid-connected simulation platform for digital/physical hybrid real-time simulation, in which RTDS uses a digital-to-analog interface to communicate with external DSP devices. Maximum power point tracking (MPPT) and grid-connected control of a 520kWp PV system are performed on the platform. And the feasibility and effectiveness of hybrid PV system are validated by the analysis of hardware-in-the-loop result in RTDS. DOI : http://dx.doi.org/10.11591/telkomnika.v12i4.4794
Volume: 12
Issue: 4
Page: 2465-2473
Publish at: 2014-04-01

Traffic Network Optimal Scheduling Paths Based on Time Intervals Division

https://ijeecs.iaescore.com/index.php/IJEECS/article/view/3303
Hao Wei , Zhang Xing
In order to make the network model was more fitting the actual condition of city traffic, this paper presents a dynamic transportation network model based on the traffic time division, and designs improved Dijkstra algorithm to solve the city traffic paths planning problem. Dijkstra algorithm is a typical single-source shortest path algorithm is used to calculate a node to all other nodes in the shortest path. The main characteristic is the starting point as the center outward expansion layers until the extension to the end. The Dijkstra algorithm is a very representative shortest path algorithm. This paper introduces new patterns to effectively combine the model and algorithm. The simulation experiments point to ten time intervals which illustrate the improved Dijkstra algorithm can avoid driving to the blocked roads in different time intervals. The algorithm has some feasibility in path planning and computation efficiency. DOI : http://dx.doi.org/10.11591/telkomnika.v12i4.4306
Volume: 12
Issue: 4
Page: 2645-2651
Publish at: 2014-04-01

Modeling Simulation and Design of Photovoltaic Array with MPPT Control Techniques

10.11591/ijape.v3.i1.pp41-50
Sangita Ramesh Nandurkar , Mini Rajeev
The Renewable energy is important part of power generation system due to diminution of fossils fuel. Energy production from photovoltaic (PV)   is widely accepted as it is clean, available in abundance, & free of cost. This paper deals with modeling of PV array including the effects of temperature and irradiation. The DC-DC converter is used for boosting low voltage of the PV array to high DC voltage.  Since the efficiency of a PV array is around 13% which is low, it is desirable to operate the module at the peak power point to improve the utilization of the PV array. A maximum power point tracker (MPPT) is used for extracting the maximum power from the solar PV array and transferring that power to the load. To track maximum power point  (MPP) Perturb & Observe  (P & O) algorithm is used which periodically perturbs the array voltage or current and compare PV output power with that of previous perturbation cycle which controls duty  cycle of DC-DC converter. The entire system is simulated in MATLAB /SIMULINK and simulation results are presented.
Volume: 3
Issue: 1
Page: 41-50
Publish at: 2014-04-01

The Optimal Design of Communication Module for Campus Smart Card

https://ijeecs.iaescore.com/index.php/IJEECS/article/view/3310
Zhu Lin
Campus Card is an important part in the digital campus life. However, due to the problems of current network design, in the course of card using, the signal channels are seized by a large number of communication tags, which leads to the phenomena of blocked communication process and unsmooth communication. In order to solve this problem, the communication module of card system has been optimized in this paper. The module consists of two parts, which are writing system and reading system. A multi-tasking multi-point mapping decomposition technique was introduced to the designation of communication module. Using the method based on the combination of Map and Reduce function to make the task decomposition which is from a sudden increase of network traffic characteristics and database, obtain a large number of sub-tasks, and accomplish the management of mutation network traffic. Experimental results show that in the task scheduling of optimized module, the solution time is short and response is fast. It can solve the communication blocked problems in the process of card using. Furthermore, it provides theoretical references for the improvement of communication system design of smart card, and promotes the construction of digital campus evolving. DOI : http://dx.doi.org/10.11591/telkomnika.v12i4.4251
Volume: 12
Issue: 4
Page: 2697-2706
Publish at: 2014-04-01

Load Flow Analysis for Process – Tank Loading Power Generation Networks Interconnection

10.11591/ijape.v3.i1.pp9-14
Radita Arindya
Establishment of interconnection links between Process -Tank Loading electrical networks bring some advantages as there are excess capacity at Process which can be utilized in principle to feed Tank Loading. Some result of power system study will be as an input for operational purposes. Concerning Motor Starting Studies and Load Flow Studies and taking into account that the transformer is off load tap changing, the best tapping position for Isolation Transformer is at -5% (primary side).  The best technical power generation configuration is proposed with configuration 2 (two) Process -TEG and 1 (one) Tank Loading-TEG running with 2 (two) interconnection, provided with appropriate load shedding system. Bare in mind that during smooth power transfer from each Process-TEG which requires 3 (three) Process-TEG running in parallel, there is an issue on kA capacity of Process switchgear. Existing setting of protection relay shall be reviewed according to the result of protection coordination study
Volume: 3
Issue: 1
Page: 9-14
Publish at: 2014-04-01

A Survey on Quality Changes in Positive, Negative and Combined Switching Strategies in Control of Three Phase Matrix Converter

10.11591/ijape.v3.i1.pp51-66
Mohammad Sarvi , Iman Soltani , Hossein Faramarzi
In this paper uses positive, negative and combined switching strategies for three phase ac/ac matrix converter .the author compares these strategies. The performance comparison of these three strategies is made under balanced operation. The simulation of three phase matrix converter feeding a three phase load was accomplished by means of the matlab/simulink software. After the simulation the comparison of the waveforms THD in three switching sequence is done. It must be mentioned that the duty cycle of the whole switches in the converter is according to Venturini switching algorithm
Volume: 3
Issue: 1
Page: 51-66
Publish at: 2014-04-01

A Research on the Application of Quantum Neural Network Optimization

https://ijeecs.iaescore.com/index.php/IJEECS/article/view/3333
Hengyang Su
The characters of fixed working hours table including the large amount of input and uncertainty of number of input parameters, make the encoding method has great influence on design method of traditional BP network combining genetic algorithm. This paper analyzes the features of searching ability of the traditional BP and genetic algorithm, based on which combining the quantum calculation and neutral model to compose quantum neurons. Then the quantum neurons are expanded to quantum neutral network to replace the traditional neutral network. Comparing to the drawbacks of the traditional genetic algorithm, the paper adopts a variation clamping mechanism. The mechanism gradually narrows the genetic operation space by fixing not sensitive single gene locus in the populations, so that the gene loci do not meet the requirements are more likely to participate in crossover and mutation to accelerate the speed up the genetic algorithm optimization and prevent it from falling into local extreme value. Finally, based on fixed table of mechanical standard working hours, compared to a variety of commonly used methods, the improved algorithm has better performance. DOI : http://dx.doi.org/10.11591/telkomnika.v12i4.4244
Volume: 12
Issue: 4
Page: 2890-2897
Publish at: 2014-04-01

Combined Operation of SVC, PSS and Increasing Inertia of Machine for Power System Transient Stability Enhancement

10.11591/ijape.v3.i1.pp15-22
Bablesh Kumar Jha , Ramjee Prasad Gupta , Upendra Prasad
In this paper improvement of transient stability by coordination of PSS (Power System Stabilizer) and SVC (Static var Compensator) and increasing inertia of synchronous machine has been observed. Because single method is not sufficient for improving stability. For this purpose a 9 bus multi machine system has been considered. Transient stability improvement has been tested subjected to three phase fault at bus 3 after 0.5 second and fault has been cleared after 1 second. By the use of PSS, SVC and by increasing inertia method for the test system the electromechanical oscillation for generator electrical power has been reduced and the steady state power transfer has been enhanced. In this paper the Inertia of the machine is not so much increased. Because after increasing inertia of the machine rotor will be havier.so that it is kept always within limit as considering its reliability and economy. And field voltage is also kept limited
Volume: 3
Issue: 1
Page: 15-22
Publish at: 2014-04-01

Sea Surface Reflection and Power Attenuation Analysis of Radio Wave in UHF Satellite Communications

https://ijeecs.iaescore.com/index.php/IJEECS/article/view/3367
Yuanming Ding , Jingjing Sun , Xue Wang
Ultra High Frequency (UHF) band is increasingly widely used in military maritime satellite communications due to its good communication performance. Electromagnetic wave emitted by satellite is reflected when reaching the sea surface, and multipath fading is very serious which causes interference on the received signal, especially when satellite elevation angle is low. In this paper, the UHF band multipath effects of sea surface were studied following the general principles of modeling in multipath effects. The numerical simulation was made based on Rayleigh criterion and the judgment basis was obtained which determines whether the specula reflected component or diffuse reflected component dominates in the reflected wave, and then the reflection coefficient of sea surface in different polarization modes were calculated. Finally, the power attenuation of reflected wave relative to direct wave for different wind speeds were simulated and analyzed. Numerical simulation results show that the greater the wind speed is, the greater the power attenuation of reflected wave will become and the more serious multipath fading will be. In addition, diffuse reflection attenuation is more serious than specular reflection. DOI : http://dx.doi.org/10.11591/telkomnika.v12i4.4787  
Volume: 12
Issue: 4
Page: 3168-3176
Publish at: 2014-04-01

Harmonic Voltage Distortions in Power Systems Due to Non Linear Loads

10.11591/ijape.v3.i1.pp67-74
Aryan Kaushik , Jyothi Varanasi
Harmonics are found to have deleterious effects on power system equipments including transformers, capacitor banks, rotating machines, switchgears and protective relays. Transformers, motors and switchgears may experience increased losses and excessive heating. Shunt filters are effective in minimizing voltage distortions. This paper describes the voltage distortions generated by non linear loads. The harmonic specifications such as harmonic factor, characteristic harmonic and non-characteristic harmonic are considered while explaining the paper. ‘MiPower’ software is used to compute the harmonic distortions in a sample power system. Accurate harmonic models are established for a non linear load. To reduce the harmonic voltages impressed upon specific parts of the sample power system, passive filters are installed at two buses. With the implementation of a passive filter at the bus with non linear load, the harmonics are greatly reduced. For the specified power system, at all the buses the total harmonic distortion has been evaluated.
Volume: 3
Issue: 1
Page: 67-74
Publish at: 2014-04-01

Remediation of Old Substations for Arc Flash hazard

10.11591/ijape.v3.i1.pp23-32
Zakir Husain , Deepak Kumar , Khushbu Thakur
Arc Flash is much different from the conventional shock hazard in the sense that it doesn’t involve direct contact of human beings with the live or energized part. The arcing energy involves high temperature of up to or beyond 20000K. This paper presents a case study of arc flash hazard analysis carried out in older industrial plant and the technological and work procedure changes that can be incorporated to reduce the incident energy level and thus provide a safer environment for the working personnels in plant.
Volume: 3
Issue: 1
Page: 23-32
Publish at: 2014-04-01
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