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25,002 Article Results

Synchronization Interfaces for Improving Moodle Utilization

10.12928/telkomnika.v10i1.776
Linawati; Udayana University Linawati , Gede; Udayana University Sukadarmika , GM Arya; Udayana University Sasmita
Many universities have applied e-learning on more than one LMS (learning management system) platforms such as Wordpress and Moodle. In addition, difficulties implementations in developing countries have occurred. Those are mainly caused by limitations and expensive of internet infrastructure. Therefore to increase Moodle application as an e-learning system, the paper proposed two synchronization interfaces. The first interface is for Moodle and Wordpress. This assists teachers to migrate their learning material in their blog in Wordpress into Moodle. Second interface is for Moodle portable performing offline LMS and Moodle performing online LMS. Moodle portable was installed in teachers and students notebooks. Moodle itself was installed and run in e-learning server. The aim is to improve Moodle utilization in the class. The results showed satisfied outcomes. Students and teachers could employ the interfaces easily and secure as they have to login using student/teacher ID, course ID, username and password.
Volume: 10
Issue: 1
Page: 179-188
Publish at: 2012-03-01

On Passband and Stopband Cascaded-Integrator-Comb Improvements Using a Second Order IIR Filter

10.12928/telkomnika.v10i1.760
Alfonso; National Polytechnic Institute Fernandez-Vazquez , Gordana Jovanovic; National Institute of Astrophysics Dolecek
This paper proposes an efficient second order IIR filter which considerably improves the passband as well as the stopband of the cascaded-integrator-comb (CIC) filter. Using the polyphase decomposition of the proposed filter, all filtering can be moved to a lower rate, which is D times less than the high input rate, where D is the decimation factor. The overall phase response of the compensated CIC is approximately linear in the passband. The design parameters are the number of cascaded CIC filter N, the decimator factor D, the passband frequency wp, and a weighted parameter a.
Volume: 10
Issue: 1
Page: 61-67
Publish at: 2012-03-01

Classification and Numbering of Dental Radiographs for an Automated Human Identification System

10.12928/telkomnika.v10i1.771
Anny; Institut Teknologi Sepuluh Nopember Yuniarti , Anindhita Sigit; Institut Teknologi Sepuluh Nopember Nugroho , Bilqis; Institut Teknologi Sepuluh Nopember Amaliah , Agus Zainal; Institut Teknologi Sepuluh Nopember Arifin
 Dental based human identification is commonly used in forensic. In a case of large scale investigation, manual identification needs a large amount of time. In this paper, we developed an automated human identification system based on dental radiographs. The system developed has two main stages. The first stage is to arrange a database consisting of labeled dental radiographs. The second stage is the searching process in the database in order to retrieve the identification result. Both stages use a number of image processing techniques, classification methods, and a numbering system in order to generate dental radiograph’s features and patterns. The first technique is preprocessing which includes image enhancement and binarization, single tooth extraction, and feature extraction. Next, we performed dental classification process which aims to classify the extracted tooth into molar or premolar using the binary support vector machine method. After that, a numbering process is executed in accordance with molar and premolar pattern obtained in the previous process. Our experiments using 16 dental radiographs that consist of 6 bitewing radiographs and 10 panoramic radiographs, 119 teeth objects in total, has shown good performance of classification. The accuracy value of dental pattern classification and dental numbering system are 91.6 % and 81.5% respectively.
Volume: 10
Issue: 1
Page: 137-146
Publish at: 2012-03-01

Dynamic Stability Enhancement of Power Systems Using Neural-Network Controlled Static-Compensator

10.12928/telkomnika.v10i1.755
D Harikrishna; National Institute of Technology Warangal D Harikrishna , N V Srikanth; National Institute of Technology Warangal N V Srikanth
This paper aims at enhancement of dynamic stability of power systems using artificial neural network (ANN) controlled static VAR compensator (SVC). SVC is proven the fact that it improves the dynamic stability of power systems apart from reactive power compensation; it has multiple roles in the operation of power systems. The auxiliary control signals to SVC play a very important role in mitigating the rotor electro-mechanical low frequency oscillations. Artificial neural network based controller is designed using the generator speed deviation, as a modulated signal to SVC, to generate the desired damping, is proposed in this paper. The ANN is trained using conventional controlled data and hence replaces the conventional controller. The ANN controlled SVC is used to improve the dynamic performance of power system by reducing the steady-state error and for its fast settling. The simulations are carried out for multi-machine power system (MMPS) at different operating conditions.
Volume: 10
Issue: 1
Page: 9-16
Publish at: 2012-03-01

Practical Control for Two-Mass Positioning Systems in Presence of Saturation

10.12928/telkomnika.v10i1.764
Fitri; Malaysia-Japan International Institute of Technology (MJIIT) Yakub , Andika Aji; College of Engineering & Information (CEIT) Wijaya , Mustafa; International Islamic University Malaysia (IIUM) Al-ani
 The precision positioning systems generally need a good controller to achieve a fast response, high accuracy and robustness. In addition, ease, simplicity of controller design structure and high motion control performance are very important for practical applications. For satisfying these requirements, nominal characteristic trajectory (NCT) with proportional integral (PI) and notch filter (NF) as a compensator has been proposed as a practical control method for two-mass rotary PTP positioning systems. However, the effect of the actuator saturation cannot be completely compensated due to integrator windup when the object parameter varies. This paper presents a method to further improve nominal characteristic trajectory following (NCTF) controller to overcome the problem of integrator windup by adopting PI anti-windup schemes. The improved NCTF controller is evaluated experimentally using two-mass rotary positioning systems. The effect of the design parameters on the robustness of the improved NCTF with anti-windup integrator controller is evaluated and compared with NCTF without anti-windup integrator and the equivalent PID controller. The results show that the improved NCTF controller is effective to compensate the effect of integrator windup.
Volume: 10
Issue: 1
Page: 91-102
Publish at: 2012-03-01

An Overview on Base Real-Time Shadow Techniques in Virtual Environments

10.12928/telkomnika.v10i1.775
Hoshang; Universiti Teknologi Malaysia (UTM) Kolivand , Mohd Shahrizal; Universiti Teknologi Malaysia (UTM) Sunar
Shadows are elegant to create a realistic scene in virtual environments. Variety types of shadow techniques encourage us to prepare an overview on all base shadow techniques. Non real-time and real-time techniques are big subdivision of shadow generation. In non real-time techniques ray tracing, ray casting and radiosity are well known and deeply described. Radiosity implemented to create very realistic shadow on non real-time scene. Although traditional radiosity algorithm is difficult to implement, we have proposed a simple one. The proposed pseudo code is easier to understand and implement. Ray tracing used to prevent of collision of movement objects. Projection shadow, shadow volume and shadow mapping are used to create real-time shadow in virtual environments. We have used projection shadow for some objects are static and have shadow on flat surface. Shadow volume used to create accurate shadow with sharp outline. Shadow mapping that is the base of most recently techniques is reconstructed. The reconstruct algorithm gives some new idea to propose another algorithm based on shadow mapping.   
Volume: 10
Issue: 1
Page: 171-178
Publish at: 2012-03-01

Static Characterization of InAs/AlGaAs Broadband Self-Assembled Quantum Dot Lasers

10.12928/telkomnika.v10i1.759
D. Ghodsi; Islamic Azad University Nahri , H. Arabshahi; Payame Noor University H. Arabshahi
The static-characteristics of InAs/AlGaAs broadband self-assembled quantum-dot laser diodes (SAQD-LDs) have been studied to solve the rate equations numerically using fourth-order Runge-Kutta method. Energy level, size, and composition distributions of the InAs/AlGaAs broadband quantum-dots (QDs) are considered and their effects on Static-characteristics are investigated. Simulated results of static-characteristics show that nonlinearity appears in light-current characteristics whereas homogeneous broadening (HB) becomes equal to inhomogeneous broadening (IHB). Slope-efficiency increases as the HB heightens up to the IHB. Exceeding the HB from IHB results in degradation of light-current characteristics. In fact, InAs/AlGaAs broadband SAQD-LD has the best performance when HB is equal to IHB. Light-current characteristics degrade and threshold current increases as the IHB enhances. We also investigate the effects of QD coverage on the laser performance and show that there is an optimum QD coverage in which the SAQD-LD operates with lowest possible threshold current and maximum output power as whatever the QD coverage enhances from that optimum amount, the threshold current increases and slope efficiency decreases.  
Volume: 10
Issue: 1
Page: 55-60
Publish at: 2012-03-01

Isolated Word Recognition Using Ergodic Hidden Markov Models and Genetic Algorithm

10.12928/telkomnika.v10i1.769
Nyoman Rizkha; Telkom Institute of Technology Emillia , Suyanto; Telkom Institute of Technology Suyanto , Warih; Telkom Institute of Technology Maharani
Speech to text was one of speech recognition applications which speech signal was processed, recognized and converted into a textual representation. Hidden Markov model (HMM) was the widely used method in speech recognition. However, the level of accuracy using HMM was strongly influenced by the optimalization of extraction process and modellling methods. Hence in this research, the use of genetic algorithm (GA) method to optimize the Ergodic HMM was tested. In Hybrid HMM-GA, GA was used to optimize the Baum-Welch method in the training process. It was useful to improve the accuracy of the recognition result which is produced by the HMM parameters that generate the low accuracy when the HMM are tested. Based on the research, the percentage increases the level of accuracy of 20% to 41%. Proved that the combination of GA in HMM method can gives more optimal results when compared with the HMM system that not combine with any method.
Volume: 10
Issue: 1
Page: 129-136
Publish at: 2012-03-01

Engine Torque Control of Spark Ignition Engine using Fuzzy Gain Scheduling

10.12928/telkomnika.v10i1.763
Aris; Diponegoro University Triwiyatno , Mohammad; Sepuluh Nopember Institute of Technology Nuh , Ari; Sepuluh Nopember Institute of Technology Santoso , I Nyoman; Sepuluh Nopember Institute of Technology Sutantra
 In the spark ignition engine system, driver convenience is very dependent on satisfying engine torque appropriate with the throttle position given by the driver. Unfortunately, sometimes the fulfillment of engine torque is not in line with fuel saving efforts. This requires the development of high performance and robust power train controllers. One way to potentially meet these performance requirements is to introduce a method of controlling engine torque using fuzzy gain scheduling. By using this method, the throttle opening commanded by the driver will be corrected by throttle correction signal that guarantees engine torque output will follow the desired engine torque input, and also reducing fuel consumption. In this case, spark ignition engine with automatic transmission is used to meet a good performance under this controller design. 
Volume: 10
Issue: 1
Page: 83-90
Publish at: 2012-03-01

Effectual SVPWM Techniques and Implementation of FPGA Based Induction Motor Drive

10.11591/ijres.v1.i1.pp11-18
Saravanan M , Nandakumar R , Veerabalaji G
This paper presents a field programmable gate array(FPGA)-based control integrated  circuits(IC) for controlling the pulsewidth modulation (PWM) inverter used in power conditioning system for ac-voltage regulation. Space vector pulsewidth modulation(SVPWM) algorithm offers great flexibility to optimise switching waveform. Among them,double edge triggering can be implemented, It consumes less power compare to other PWM techniques. The SVPWM pulses thus generated through Xilinx is given as switching pulses to voltage source inverter(VSI) circuit to trigger the motor. The delay time of PWM output is programmable and SVPWM control IC is reprogrammable.It shows the advantage of lower total harmonic distortion(THD) without increasing the switching losses. Results  are provided along with simulation analysis in terms of THD,output fundamental voltage and voltage transfer ratio to verify the feasibility of operation. The SVPWM switching pattern has been achieved with a fundamental frequency of  50HZ.
Volume: 1
Issue: 1
Page: 11-18
Publish at: 2012-03-01

A Novel FPGA based Leading One Anticipation Algorithm for Floating Point Arithmetic Units

10.11591/ijres.v1.i1.pp19-24
Ashwini Suresh Deshmukh
In multimedia Systems-on-Chips, the design of specialized IEEE-754-compliant floating point arithmetic units (FPU) is critical with respect to both operating speed and silicon area demand. Leading one anticipation is a well-known issue in the implementation of high speed FPUs. We investigated a novel leading one anticipation algorithm allowing us to significantly reduce the anticipation failure rate with respect to the state-of the art. We embedded our technique into a complete FPU and compared its performance against existing solutions, definitely showing both area savings and total latency reduction.
Volume: 1
Issue: 1
Page: 19-24
Publish at: 2012-03-01

Real-time Optical-flow Computation for Motion Estimation under Varying Illumination Conditions

10.11591/ijres.v1.i1.pp25-36
Julio C. Sosa , Roberto Rodríguez , Víctor H. García Ortega , Rubén Hernández
The optical flow approach has emerged as a major technique for estimating object motion in image sequences. However, the obtained results by most optical flow techniques are poor because they are strongly affected by large illumination changes and by motion discontinuities. On the other hand, there have been two thrusts in the development of optical flow algorithms. One has emphasized higher accuracy; the other faster implementation. These two thrusts have been independently pursed, without addressing the accuracy vs. efficiency trade-offs. The optical flow computation requires high computing resources and is highly affected by changes in the illumination conditions in most of the existing techniques. In this paper, a new strategy for image sequence processing is proposed. The data reduction achieved with this strategy allows a faster optical flow computation. In addition, the proposed architecture is a hardware custom implementation  in EP1S60F1020 FPGA showing the achieved performance.
Volume: 1
Issue: 1
Page: 25-36
Publish at: 2012-03-01

Simplified VHDL Coding of Modified Non-Restoring Square Root Calculator

10.11591/ijres.v1.i1.pp37-42
Tole Sutikno , Aiman Zakwan Jidin , Auzani Jidin , Nik Rumzi Nik Idris
Square root calculation is one of the most useful and vital operation in digital signal processing which in recent generations of processors, the operation is performed by the hardware. The hardware implementation of the square root operation can be achieved by different means, but it is very dependent on programmer's sense and ability to write efficient hardware designs. This paper offers universal and shortest VHDL coding of modified non-restoring square root calculator. The main principle of the method is similar with conventional non-restoring algorithm, but it only uses subtract operation and append 01, while add operation and append 11 is not used. The strategy has conducted to implement successfully in FPGA hardware, and offer an efficient in hardware resource, and it is superior.
Volume: 1
Issue: 1
Page: 37-42
Publish at: 2012-03-01

A Novel High Speed FPGA Architecture for FIR Filter Design

10.11591/ijres.v1.i1.pp1-10
Sachin B. Jadhav , Nikhil Niwas Mane
This paper presents the details of hardware implementation of linear phase FIR filter using merged MAC architecture. Speed of convolution operation of FIR filter is improved using merged MAC architecture. By exploiting the reduced complexity made possible by the use of sparse powers of two partial products terms coefficients, an FIR filter tap can be implemented with 2B full adders, and 2B latches, where B is intermediate wordlegnth. Word and bit level parallelism allows high sampling rates, limited only by the full adder delay. The proposed architecture is based on binary tree constructed using modified 4:2 and 5:2 compressor circuits. Increasing the speed of operation is achieved by using higher modified compressors in critical path. Our objective of work is, to increase the speed of multiplication and accumulation operation by minimizing the number of combinational gates using higher n: 2 compressors, which is required more for Array multiplier at the time of implementation of array architecture. This novel architecture allows the implementation of high sampling rate filters of significant length on FPGA Spartan-3 device (XC3S400 PQ-208). The simulation result shows convolution output of digital FIR filter which is done using Questa Sim 6.4c Mentor Graphics tool. The experimental test of the proposed digital FIR filter is done using Spartan-3 device (XC3S400 PQ-208)
Volume: 1
Issue: 1
Page: 1-10
Publish at: 2012-03-01

Human Identification Based on Electrocardiogram and Palmprint

https://ijece.iaescore.com/index.php/IJECE/article/view/5396
Sara Zokaee , Karim Faez
In this paper, a new approach in human identification is investigated. For this purpose, we fused ECG and Palm print biometrics to achieve a multimodal biometric system. In the proposed system for fusing biometrics, we used MFCC approach in order to extract features of ECG biometric and PCA to extract features of Palm print. The features undergo a KNN classification. The performance of the algorithm is evaluated against the standard MIT-BIH and POLYU databases. Moreover, in order to achieve more realistic and reliable results, we gathered Holter ECG recordings acquired from 50 male and female subjects in age between 18 and 54. The numerical results indicated that the algorithm achieved 94.7% of the detection rate.DOI:http://dx.doi.org/10.11591/ijece.v2i2.292
Volume: 2
Issue: 2
Page: 261-266
Publish at: 2012-02-26
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