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27,404 Article Results

A Fast and Efficient Shape Descriptor for an Advanced Weed Type Classification Approach

10.11591/ijece.v6i3.pp1168-1175
Adil Tannouche , Khalid Sbai , Miloud Rahmoune , Amine Zoubir , Rachid Agounoune , Rachid Saadani , Abdelali Rahmani
In weed management, the distinction between monocots and dicots species is an important issue. Indeed, the yield is much higher with the application of a selective treatment instead of using a broadcast herbicide overall the parcel. This article presents a fast shape descriptor designed to distinguish between these two families of weeds. The efficiency of the descriptor is evaluated by analyzing data with the pattern recognition process known as the discriminant factor analysis (DFA). Excellent results have been obtained in the differentiation between these two weed species
Volume: 6
Issue: 3
Page: 1168-1175
Publish at: 2016-06-01

The Effects of Spread-Spectrum Techniques in Mitigating Conducted EMI to LED Luminance

10.11591/ijece.v6i3.pp1332-1343
Mohammad Yanuar Hariyawan , Risanuri Hidayat , Eka Firmansyah
Rapid voltage and current changes in recently ubiquitous LED driver have a potency to interfere other devices. Solutions with special converter design, component design, EMI filter, and spread-spectrum techniques have been proposed. Due to cost-size-weight constraints, spread-spectrum technique seems a potential candidate in alleviating EMI problem in LED application. In this paper, the effectiveness of conducted EMI suppression performance of the spread-spectrum technique is evaluated. Spread-spectrum techniques applied by giving disturbance to the system LED driver with 3 profile signals, filtered square, triangular, and sine disturbance signal to the switching pattern of a buck LED driver. From the test results, 472.5 kHz triangular and 525 kHz sine signal can reduce EMI about 42 dBuV whilethe filtered square signal can reduce EMI 40.70 dBuV compare with fundamental constantfrequency reference 669 kHz. The average reduction in the power level of the third signal inthe frequency range of 199 kHz to 925 kHz for 5.154281 dBuV and the filtered square signal can reduce the average power level better than other signal disturbance of 5.852618 dBuV.LED luminance decrease when the spread-spectrum technique is applied to the system about 2814 lux.
Volume: 6
Issue: 3
Page: 1332-1343
Publish at: 2016-06-01

Genetic Algorithm Application in Asymmetrical 9-Level Inverter

10.11591/ijpeds.v7.i2.pp521-530
Rachid Taleb , M’hamed Helaimi , Djilali Benyoucef , Zinelaabidine Boudjema
Selective harmonic elimination (SHE) has been a widely researched alternative to traditional PWM techniques. This paper presents the selective harmonic elimination of a uniform step asymmetrical multilevel inverter (USAMI) using genetic algorithm (GA) which eliminates specified higher order harmonics while maintaining the required fundamental voltage. This technique can be applied to USAMI with any number of levels. As an example, in this paper a 9-level USAMI is considered and the optimum switching angles are calculated to eliminate the 5th, 7th and 11th harmonics.
Volume: 7
Issue: 2
Page: 521-530
Publish at: 2016-06-01

A Novel Optimal PI Parameter Tuning Strategy to Improve Constant Switching Performance of Direct Torque Control

10.11591/ijpeds.v7.i2.pp422-430
Sundram Ramahlingam , Auzani Jidin , Tole Sutikno
This paper presents a novel method of optimal Propotional-Intergral (PI) controller’s parameter tuning strategy in-order to improve the Constant Switching Performance of 3-phase DTC shceme. The Direct Torque Control (DTC) sheme is acknowledged to provide fast decoupled control over the torque output and stator flux via a simple control structure. However, DTC sheme has two major downsides, which are the inconsistent inverter switching frequency and high torque output ripple. The main reason that contributes to these tribulations is the usage of hysteresis comparators in order to control the output torque. The realization of PI based controller method as replacement of hyterisis controller in DTC system able to provide significant solutions to over come the fall back while retaining the simple control structure of conventional DTC. The combination usage of higher sampling controller DS1004 and also 3-level CHMI in this system can further minimize the output torque ripple by providing higher resolution with lower digital error and greater number of vectors. This paper presents detail explanation and calculation of optimal PI parameter tuning strategy consecutively to enhance the performance of 3-level DTC system. In order to verify the feasibility of the proposed method experimentation, the proposed method is compared with convention DTC system via simulation and experiment results.
Volume: 7
Issue: 2
Page: 422-430
Publish at: 2016-06-01

URL ATTACKS: Classification of URLs via Analysis and Learning

10.11591/ijece.v6i3.pp980-985
M. Rajesh , R. Abhilash , R. Praveen Kumar
Social Networks such as Twitter, Facebook play a remarkable growth in recent years. The ratio of tweets or messages in the form of URLs increases day by day. As the number of URL increases, the probability of fabrication also gets increased using their HTML content as well as by the usage of tiny URLs. It is important to classify the URLs by means of some modern techniques. Conditional redirection method is used here by which the URLs get classified and also the target page that the user needs is achieved. Learning methods also introduced to differentiate the URLs and there by the fabrication is not possible. Also the classifiers will efficiently detect the suspicious URLs using link analysis algorithm.
Volume: 6
Issue: 3
Page: 980-985
Publish at: 2016-06-01

Efficient Low-Complexity Digital Predistortion for Power Amplifier Linearization

10.11591/ijece.v6i3.pp1096-1105
Siba Monther Yousif , Roslina M. Sidek , Anwer Sabah Mekki , Nasri Sulaiman , Pooria Varahram
In this paper, a low-complexity model is proposed for linearizing power amplifiers with memory effects using the digital predistortion (DPD) technique. In the proposed model, the linear, low-order nonlinear and high-order nonlinear memory effects are computed separately to provide flexibility in controlling the model parameters so that both high performance and low model complexity can be achieved. The performance of the proposed model is assessed based on experimental measurements of a commercial class AB power amplifier by applying a single-carrier wideband code division multiple access (WCDMA) signal. The linearity performance and the model complexity of the proposed model are compared with the memory polynomial (MP) model and the DPD with single-feedback model. The experimental results show that the proposed model outperforms the latter model by 5 dB in terms of adjacent channel leakage power ratio (ACLR) with comparable complexity. Compared to MP model, the proposed model shows improved ACLR performance by 10.8 dB with a reduction in the complexity by 17% in terms of number of floating-point operations (FLOPs) and 18% in terms of number of model coefficients.
Volume: 6
Issue: 3
Page: 1096-1105
Publish at: 2016-06-01

Enhanced Torque Control and Reduced Switching Frequency in Direct Torque Control Utilizing Optimal Switching Strategy for Dual-Inverter Supplied Drive

10.11591/ijpeds.v7.i2.pp328-339
M. Khairi Rahim , Auzani Jidin , Tole Sutikno
Direct Torque Control (DTC) of induction machine has received wide acceptance in many adjustable speed drive applications due to its simplicity and high performance torque control. However, the DTC using a common two-level inverter poses two major problems such as higher switching frequency (or power loss) and larger torque ripple. These problems are due to inappropriate voltage vectors which are selected among a limited number of voltage vectors available in two-level inverter. The proposed research aims to formulate an optimal switching strategy using Dual-Inverter Supplied Drive for high performances of DTC. By using dual-inverter supplied, it provides greater number of voltage vectors which can offer more options to select the most appropriate voltage vectors. The most appropriate voltage vectors should able to produce minimum torque slope but sufficient to satisfy torque demands. The identification is accomplished by using an equation of rate of change of torque which is derived from the induction machine equations. The proposed strategy also introduces a block of modification of torque error status which is responsible to modify the status such that it can determine the most optimal voltage vectors from a look-up table, according to motor operating conditions. The improvements obtained are as follows; 1) minimization of switching frequency (reduce power loss), and 2) reduction of torque ripple. Some improvements obtained in the proposed strategy were verified via experimentations.
Volume: 7
Issue: 2
Page: 328-339
Publish at: 2016-06-01

Analysis and Implementation of a High Boost Ratio DC-DC Converter for Minimizing Commutation Torque Ripple in Brushless DC Motor

10.11591/ijpeds.v7.i2.pp583-600
M. Senthil Raja , B. Geethalakshmi
Brushless dc motor still suffers from commutation torque ripple, which primarily depends on transient line current in the commutation interval. In order to control the incoming and outgoing phase currents to change at the same rate during commutation, this paper presents a novel high boost ratio DC-DC circuit topology in the front end of the inverter. With a suitable closed loop control scheme, the proposed high boost ratio DC-DC converter is operated with two different duty ratios one during commutation period and the other during non commutation period. The cause of commutation ripple is analyzed, and the way to adjust the duty ratio for obtaining the desired dc link voltage is introduced in detail. Finally, simulation and experimental results show that, compared with the existing dc–dc converter topologies, the proposed method can obtain the desired voltage much faster and minimize commutation torque ripple more efficiently
Volume: 7
Issue: 2
Page: 583-600
Publish at: 2016-06-01

Analysis of IEEE 802.15.4 Beacon-Enabled MAC Protocol

10.11591/ijece.v6i3.pp1122-1132
Nga Dinh , Sangsoon Lim
This paper aims to develop several mathematical models to study medium access control (MAC) protocol in the IEEE 802.15.4 beacon-enabled mode with star topology. In particular, the MAC protocol which employs a slotted carrier-sense multiple access with collision avoidance (CSMA/CA) algorithm used in the contention access period (CAP) of a superframe is modelled. The analysis studies the effectiveness of the CSMA/CA algorithm and provides explicit mathematical expressions for power consumption, access delay, and data frame drop probability. The proposed models precisely follow CSMA/CA algorithm in MAC protocol of beacon-enabled mode and differ from those previously published in the literature as 1) they are derived based on data frame generation rate of end devices, 2) they provide a completed expression for frame access delay, and 3) lowpower states of end devices are considered for power efficiency evaluations. The paper shows how power consumption of end devices is improved on the balance with data frame delay. The validity of the proposed models is confirmed and complemented by extensive simulations.
Volume: 6
Issue: 3
Page: 1122-1132
Publish at: 2016-06-01

Direct Instantaneous Power Control of Three-level Grid-connected

10.11591/ijece.v6i3.pp1260-1273
Yang Yong
Power electronic grid-connected inverters are widely applied as grid interface in renewable energy sources. This paper presents direct instantaneous power control of a three-phase three-level Neutral Point Clamped (NPC) grid-connected inverter in photovoltaic generation systems. The system consists of a PV array, DC/DC converter, three-level NPC LC filter and the grid. In order to achieve maximum power point  tracking (MPPT), an adaptive perturb and observe MPPT is used. For balancing the neutral point (NP) voltage, the control scheme through proportional integral (PI) control according to  the direction of the NP current based on redundant vector selection is used. Direct instantaneous power control is developed in a rotating synchronous dq reference frame with space vector modulation with improved operation performance study of the positive sequence detector (PSD) plus a synchronous a synchronous reference frame phase-locked loop (PLL) as the synchronization method. The performance of the proposed method is investigated by a grid-connected photovoltaic system with a nominal power of 12kW. The feasibility of the proposed method is verified through experimental results, showing good steady-state and dynamic performance.
Volume: 6
Issue: 3
Page: 1260-1273
Publish at: 2016-06-01

Performance Evaluation of Modelling and Simulation of Lead Acid Batteries for Photovoltaic Applications

10.11591/ijpeds.v7.i2.pp472-480
A. Selmani , A. Ed-Dahhak , M. Outanoute , A. Lachhab , M. Guerbaoui , B. Bouchikhi
Lead-acid batteries have been the most widely used energy storage units in stand-alone photovoltaic (PV) applications. To make a full use of those batteries and to improve their lifecycle, high performance charger is often required. The implementation of an advanced charger needs accurate information on the batteries internal parameters. In this work, we selected CIEMAT model because of its good performance to deal with the widest range of lead acid batteries. The performance evaluation of this model is based on the co-simulation LabVIEW/Multisim. With the intention of determining the impact of the charging process on batteries, the behaviour of different internal parameters of the batteries was simulated. During the charging mode, the value of the current must decrease when the batteries’ state of charge is close to be fully charged.
Volume: 7
Issue: 2
Page: 472-480
Publish at: 2016-06-01

Machine Learning Techniques on Multidimensional Curve Fitting Data Based on R- Square and Chi-Square Methods

10.11591/ijece.v6i3.pp974-979
Vidyullatha P , D. Rajeswara Rao
Curve fitting is one of the procedures in data analysis and is helpful for prediction analysis showing graphically how the data points are related to one another whether it is in linear or non-linear model. Usually, the curve fit will find the concentrates along the curve or it will just use to smooth the data and upgrade the presence of the plot. Curve fitting checks the relationship between independent variables and dependent variables with the objective of characterizing a good fit model. Curve fitting finds mathematical equation that best fits given information. In this paper, 150 unorganized data points of environmental variables are used to develop Linear and non-linear data modelling which are evaluated by utilizing 3 dimensional ‘Sftool’ and ‘Labfit’ machine learning techniques. In Linear model, the best estimations of the coefficients are realized by the estimation of R- square turns in to one and in Non-Linear models with least Chi-square are the criteria. 
Volume: 6
Issue: 3
Page: 974-979
Publish at: 2016-06-01

Special features of radio interception of APCO P25 messages in Russia

10.11591/ijece.v6i3.pp1072-1076
Dmitry Sergeevich Silnov
Many special forces in Russia use APCO P25 encoding while radio talks. Using google speech or yandex speechkit while decoding radio talks can give huge advantage. Search engines can index decoded text or knowledge base can be created.
Volume: 6
Issue: 3
Page: 1072-1076
Publish at: 2016-06-01

Delay Comparison for 16x16 Vedic Multiplier Using RCA and CLA

10.11591/ijece.v6i3.pp1205-1212
M. Bhavani , M. Siva Kumar , K. Srinivas Rao
In any integrated chip compulsory adders are required because first they are fast and second are the less power consumption and delay. And at the same time multiplication process is also used in various applications. So as the speed of multiplier increases then the speed of processor also increases. And hence we are proposing the Vedic multiplier using these adders. Vedic multiplier is an ancient mathematics which uses mainly 16 sutras for its operation. In this project we are using “urdhva triyagbhyam” sutra to do our process. This paper proposes the Vedic multiplier using the adders ripple carry adder(RCA) and carry look ahead adder(CLA) and puts forward that CLA is better than RCA.The major parameters we are simulating here are number of slices and delay. The code is written by using Verilog and is implemented using Xilinx ISE Design Suite.
Volume: 6
Issue: 3
Page: 1205-1212
Publish at: 2016-06-01

Modelling the Effect of Applied Voltage and Frequency on Electroluminescence in Polymeric Material

10.11591/ijece.v6i3.pp1375-1384
N.A. Bani , Z Abdul-Malek , F Muhammad-Sukki , A Abubakar Mas’ud , M.N. Muhtazaruddin , K Kamardin , J.J. Jamian , H Ahmad
Electroluminescence method has been used by several researchers to observe the behaviour of an aged polymeric material. Electroluminescence is a phenomenon that occurs when the atoms of a material are being excited due to the application of and external high electrical stresses. The changes in the energy level of these excitation states can be used as an indicator for the initiation of electrical ageing. There are several factors that affect the behaviour of electroluminescence emission such as, among others, applied voltage, applied frequency, ageing of material and types of materials and gases used are discussed in this paper. A mathematical approach relating these factors and the intensity of electroluminescence is proposed through the aid of Dimensional Analysis method. A close relationship is obtained between experimental and simulation that suggests this mathematical approach can be utilized as a tool to predict electrical ageing of insulation material.
Volume: 6
Issue: 3
Page: 1375-1384
Publish at: 2016-06-01
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