Articles

Access the latest knowledge in applied science, electrical engineering, computer science and information technology, education, and health.

Advanced Search
Filter Icon

Filters article

Years

FAQ Arrow
Single Year
Range Year
0
0

Source Title

FAQ Arrow

Authors

FAQ Arrow

23,598 Article Results

Efficient Kernel-based Two-Dimensional Principal Component Analysis for Smile Stages Recognition

10.12928/telkomnika.v10i1.766
Rima Tri; University of Trunojoyo Madura Wahyuningrum , Fitri; University of Trunojoyo Madura Damayanti
 Recently, an approach called two-dimensional principal component analysis (2DPCA) has been proposed for smile stages representation and recognition. The essence of 2DPCA is that it computes the eigenvectors of the so-called image covariance matrix without matrix-to-vector conversion so the size of the image covariance matrix are much smaller, easier to evaluate covariance matrix, computation cost is reduced and the performance is also improved than traditional PCA. In an effort to improve and perfect the performance of smile stages recognition, in this paper, we propose efficient Kernel based 2DPCA concepts. The Kernelization of 2DPCA can be benefit to develop the nonlinear structures in the input data. This paper discusses comparison of standard Kernel based 2DPCA and efficient Kernel based 2DPCA for smile stages recognition. The results of experiments show that Kernel based 2DPCA achieve better performance in comparison with the other approaches. While the use of efficient Kernel based 2DPCA can speed up the training procedure of standard Kernel based 2DPCA thus the algorithm can achieve much more computational efficiency and remarkably save the memory consuming compared to the standard Kernel based 2DPCA.
Volume: 10
Issue: 1
Page: 113-118
Publish at: 2012-03-01

CT-FC: more Comprehensive Traversal Focused Crawler

10.12928/telkomnika.v10i1.777
Siti; Surabaya Adhitama Institute of Technology Maimunah , Husni S; Bandung Institute of Technology Sastramihardja , Dwi H; Bandung Institute of Technology Widyantoro , Kuspriyanto; Bandung Institute of Technology Kuspriyanto
 In today’s world, people depend more on the WWW information, including professionals who have to analyze the data according their domain to maintain and improve their business. A data analysis would require information that is comprehensive and relevant to their domain. Focused crawler as a topical based Web indexer agent is used to meet this application’s information need. In order to increase the precision, focused crawler face the problem of low recall. The study on WWW hyperlink structure characteristics indicates that many Web documents are not strong connected but through co-citation & co-reference. Conventional focused crawler that uses forward crawling strategy could not visit the documents in these characteristics. This study proposes a more comprehensive traversal framework. As a proof, CT-FC (a focused crawler with the new traversal framework) ran on DMOZ data that is representative to WWW characteristics. The results show that this strategy can increase the recall significantly.
Volume: 10
Issue: 1
Page: 189-198
Publish at: 2012-03-01

IEEE 802.11n Physical Layer Implementation on Field Programmable Gate Array

10.12928/telkomnika.v10i1.761
Hendra; Universitas Islam Indonesia Setiawan , Yuhei; Kyushu Institute of Technology Nagao , Masayuki; Kyushu Institute of Technology Kurosaki , Hiroshi; Kyushu Institute of Technology Ochi
Register transfer level (RTL) development is a time cost step that requires high diligence and fidelity to get the valid interpretation of abstraction function of digital circuit. In this research, we introduce and prove that Model-Based Design Process (MBDP) is an effective and efficient way to develop a RTL complex system such as wireless communication. Using MBDP flow, we interpret, develop, and verify the physical layer RTL of a new standard that ratified on the end 2009, i.e. IEEE 802.11n wireless local area network (WLAN). The result of this research is a prototyping FPGA StratixII EP2S180 that has properly worked as a 2x2 MIMO WLAN with maximum throughput 144 Mbps. 
Volume: 10
Issue: 1
Page: 67-74
Publish at: 2012-03-01

Compressed Sensing for Thoracic MRI with Partial Random Circulant Matrices

10.12928/telkomnika.v10i1.772
Windra; Ma Chung University Swastika , Hideaki; Chiba University Haneishi
The use of circulant matrix as the sensing matrix in compressed sensing (CS) scheme has recently been proposed to overcome the limitation of random or partial Fourier matrices. Aside from reducing computational complexity, the use of circulant matrix for magnetic resonance (MR) image offers the feasibility in hardware implementations. This paper presents the simulation of compressed sensing for thoracic MR imaging with circulant matrix as the sensing matrix. The comparisons of reconstruction of three different type MR images using circulant matrix are investigated in term of number of samples, number of iteration and signal to noise ratio (SNR). The simulation results showed that circulant matrix works efficiently for encoding the MR image of respiratory organ, especially for smooth and sparse image in spatial domain.
Volume: 10
Issue: 1
Page: 147-154
Publish at: 2012-03-01

Operation of a Fuzzy Controlled Half-Bridge DC-Converter as a Welding Current-Source

10.12928/telkomnika.v10i1.756
Zahra; Islamic Azad University Malekjamshidi , Mohammad; Islamic Azad University Jafari , Kourosh; Arsanjan Technical and Professional Educating Center Mahmoodi
 A new Fuzzy controlled welding machine (FCWM) current source is introduced in this paper and the results of the new control method are explained. The Fuzzy controller is applied to the welding machine to improve some problems of welding process. The new intelligent controller guaranties a constant current during welding to improve welding quality. It also provides some features such as hot-start and anti-stuck function and a standby mode for energy saving. The effectiveness of this intelligent welding machine was proven by the experimental results and durable test.  The results show that designed FCWM can be used in mobile welding industries.
Volume: 10
Issue: 1
Page: 17-24
Publish at: 2012-03-01

Multiobjective H2/H∞ Control Design with Regional Pole Constraints

10.12928/telkomnika.v10i1.765
Hardiansyah; Tanjungpura University Hardiansyah , Junaidi; Tanjungpura University Junaidi
This paper presents multiobjective H2/H∞ control design with regional pole constraints. The state feedback gain can be obtained by solving a linear matrix inequality (LMI) feasibility problem that robustly assigns the closed-loop poles in a prescribed LMI region. The proposed technique is illustrated with applications to the design of stabilizer for a typical single-machine infinite-bus (SMIB) power system. The LMI-based control ensures adequate damping for widely varying system operating conditions. The simulation results illustrate the effectiveness and robustness of the proposed stabilizer.
Volume: 10
Issue: 1
Page: 103-112
Publish at: 2012-03-01

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
1 2 3
...
1573 1574
Show 1550 of 1574

Discover Our Library

Embark on a journey through our expansive collection of articles and let curiosity lead your path to innovation.

Explore Now
Library 3D Ilustration