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28,451 Article Results

STATCOM Model for Integration of Wind Turbine to Grid

10.11591/ijeecs.v12.i9.pp6519-6525
Rajib Baran Roy , Md. Rokonuzzaman
In order to reduce the green house gas emission and dependency on conventional energy sources, the utilization of renewable energy sources for electricity generation is increasing day by day. The performance of the wind turbine as well as the power quality is determined according to the guidelines and regulations of IEC-61400 (International Electro-technical Commission) standard. When wind turbine is connected to a grid system, the power quality measurements like active power, reactive power, frequency, voltage sag, voltage swell, flicker and harmonics are needed to be considered. In this paper, a STATCOM (static compensator) model is proposed for improving the power quality in case of feeding electricity generated from the wind turbine into the grid.The proposed STATCOM control scheme for improving the wind power quality is designed and simulated by using Simpower toolbox of MATLAB Simulink. According to the simulated results, the bus voltage is improved after adding STATCOM in the simulated model which justifies the feasibility and practicability of the proposed FACTS (Flexible AC transmission system) device.
Volume: 12
Issue: 9
Page: 6519-6525
Publish at: 2014-09-01

Estimated Spectral Reflectances of Jati Belanda Leaf Using Fourier Transformation

10.11591/ijeecs.v12.i9.pp6958-6964
Dhieka Avrilia Lantana , Yeni Herdiyeni , Irmanida Batubara
This research proposes new method to estimate spectral reflectances of Jati Belanda (Guazuma ulmifolia) leaf based on digital image color. Jati Belanda is a medicinal plant containing antioxidant compounds. Spectral reflectances can be used to estimate chemical compounds but the tools to obtain spectral reflectances is very expensive. To estimate the Jati Belanda leaf reflectance values based on digital image color, we used Fourier Transformation. The estimated spectral reflectances is evaluated using root mean square error (RMSE) and goodness-of-fit coefficient (GFC). According to the experiment, dataset used is 276 leaves of medicinal plants and the best polynomial transformation is 3rd order with RMSE value 4,83 and GFC value 0.96. The future work could estimate the amount of chemical compounds in Jati Belanda Leaf using estimated spectral reflectances. Estimated spectral reflectances is  an important part of estimated the amount of chemical compounds.
Volume: 12
Issue: 9
Page: 6958-6964
Publish at: 2014-09-01

Some Results of Bondage Number of (n,k)-Star Graphs

https://ijeecs.iaescore.com/index.php/IJEECS/article/view/2645
Yunchao Wei , Hongxian Zhu , Junli Han
In the computer network, bondage number is one of the most important parameters to measure the control theory of the computer network, denoted by b(G) for a network graph G. But predecessors have proved that computing them are very hard. So computing b(G) of some particular known gr-aphs is extremely valuable. In this paper, we determine b(Sn,2) and the precise lowerbound of b(G) of (n,k)-star graphs, denoted by Sn,k followed by some relative conclusions of n-star, denoted by Sn as the isomorphism of Sn,n-1. In addition, our method giving dominating set of Sn,k is easily understood, which presented a broadcast algorithm to determine dominating set of Sn,k. DOI: http://dx.doi.org/10.11591/telkomnika.v11i9.3285  
Volume: 11
Issue: 9
Page: 5316-5321
Publish at: 2014-09-01

Matrix Mask Overlapping and Convolution Eight Directions for Blood Vessel Segmentation on Fundus Retinal Image

10.12928/telkomnika.v12i3.97
Arif; Trunojoyo University - Madura Muntasa , Indah Agustien; Trunojoyo University - Madura Sirajudin , Moch Kautsar; Trunojoyo University - Madura Sophan
Diabetic Retinopathy is one of the diseases that have the effect of a high mortality rate after heart disease and cancer.  However, the disease can be early detected through blood vessels and the optic nerve head in Fundus images. Blood vessels separation of the optic nerve head required high effort when it is conducted manually, therefore it is necessary that the appropriate method to perform segmentation of the object. Level Set method is well-known as object segmentation method based on object deformable. However, the methods have the disadvantage; it requires initialization before the segmentation process. In this research, segmentation method without initialization process is proposed. The segmentation is conducted by using the maximum value selection results of convolution 8 directions. Experimental results show that, proposed method has obtained 89.48% accuracy. Segmentation errors are caused by small branches, where they are not connected, so that the objects are supposed as noises
Volume: 12
Issue: 3
Page: 631-638
Publish at: 2014-09-01

Robust Provable Data Possession Protocol

10.11591/ijeecs.v12.i9.pp6969-6977
Chao Feng , Yixian Yang , Jing Zhang , Yang Xin
Provable data possession (PDP) is a technique for ensuring the validity of data in storage outsourcing. The main issue is how to frequently, efficiently verify that an untrusted server is correctly storing its client’s outsourced data. In this paper, we introduce a robust provable data possession protocol that allows a client that has stored he/her data at an untrusted server to verify the validity of data without retrieving it. The client preprocesses the data and sends it to an untrusted server for storage, while keeping a small amount of meta-data. Then the client generates probabilistic proofs of possession by sampling a random set of blocks from the server to prove that the stored data has not been tampered with or deleted, which drastically reduces I/O costs. In additions, by means of the careful integration of online codes and PDP (O-PDP), the scheme can recovers a small amount of the file, once it has been deleted. Finally, we conduct an experimental evaluation to study the performance, and robustness of O-PDP.
Volume: 12
Issue: 9
Page: 6969-6977
Publish at: 2014-09-01

Performance of Chaos-Based Encryption Algorithm for Digital Image

10.12928/telkomnika.v12i3.106
Suryadi; Department of Mathematics Universitas Indonesia MT , Eva; Department of Mathematics Nurpeti
Presentation of information in digital form is highly vulnerable againts information abusing. Digital image is one of digital information which is frequently becomes a target of crime. Therefore, reliable, secure, and fast security technique are required in digital image information. In this study, chaos-based encryption algorithm for digital image is built to improve endurance from brute force and known plaintext attack. The algorithm using logistic map as a random number generator for key stream. According to test and analysis, this algorithm has key space of , key sensitivity up to , the key stream is proved random, and the distribution of pixels value from encrypted image is proved uniform. So, it can be concluded that, the algorithm is very difficult to be cracked by brute force attack and also known plaintext attack.
Volume: 12
Issue: 3
Page: 675-682
Publish at: 2014-09-01

Improved SPRINT Algorithm and its Application in the Physical Data Analysis

10.11591/ijeecs.v12.i9.pp6909-6920
Yazhi Ding , Zhigao Zheng , Ma Rong
In order to determine the human physical condition according to the conventional tested data quickly and accurately, in this paper we proposed a trend selection based scalable parallelizable induction of decision trees algorithm (TESTSPRINT), based on the concept of pure interval and trend selection method. Based on the basic test data such as height, weight and grip strength, we can create a human physical condition decision tree quickly; according to the decision tree we can determine human physical health status quickly. Theoretic analysis and experimental demonstrations show that the algorithms this paper proposed outperforms existing algorithms in time and space complexity, and it was proved fruitful applications in the decision human physical health status with high accuracy.
Volume: 12
Issue: 9
Page: 6909-6920
Publish at: 2014-09-01

Structure and Mechanical Analysis of Single Cantilever Piezoelectric Energy Harvester

10.11591/ijeecs.v12.i9.pp6479-6493
Jie Zhao , Fenglin Yao , Shiqiao Gao
Cantilever energy harvester has become the main structure in piezoelectric energy harvester. There are two different methods to build their model. One is lumped parameter model; the other is distributed parameter model. By building their govern equation and solving them, amplitude-frequency characteristics, power and natural frequency of the model are obtained. Comparison of model frequency and amplitude are made between two models. Problems, scope of application and correct method for energy harvester are also given which provides reliable theoretical reference and makes solid foundation for energy harvester design.
Volume: 12
Issue: 9
Page: 6479-6493
Publish at: 2014-09-01

Failure Mechanism Analysis and Failure Number Prediction of Wind Turbine Blades

10.12928/telkomnika.v12i3.76
Yu; Harbin University of Science and Technology Chun-yu , Guo; Harbin University of Science and Technology Jian-ying , Xin; Harbin University of Science and Technology Shi-guang
Pertinent to the problems that wind turbine blades operate in complicated conditions, frequent failures and low replacement rate as well as rational inventory need, this paper, we build a fault tree model based on in-depth analysis of the failure causes. As the mechanical vibration of the wind turbine takes place first on the blades, the paper gives a detailed analysis to the Failure mechanism of blade vibration. Therefore the paper puts forward a dynamic prediction model of wind turbine blade failure number based on the grey theory. The relative error between its prediction and the field investigation data is less than 5%, meeting the actual needs of engineering and verifying the effectiveness and applicability of the proposed algorithm. It is of important engineering significance for it to provide a theoretical foundation for the failure analysis, failure research and inventory level of wind turbine blades.
Volume: 12
Issue: 3
Page: 533-540
Publish at: 2014-09-01

One-Time Password Implementation on Lego Mindstorms NXT

10.12928/telkomnika.v12i3.92
Barlian; University of Brawijaya Henryranu P , Heru; University of Brawijaya Nurwarsito , Wijaya; University of Brawijaya Kurniawan
One of the factors that affect the security of a network or system is user authentication and unfortunately at times it can be said not safe anymore. Brute force attacks on password systems are dominant (static) potential to penetrate network security or user authentication system. One way to overcome these drawbacks is to use the One Time Password (OTP) algorithm. OTP is a password security system using dynamic passwords. The password will be valid only for a session only, and so want to get into the next session, the password will be changed to the sequence/combination in accordance with certain rules or randomly determined by the user. In this research, author will be analyzed how the reliability of the OTP algorithm by applying it to a LEGO Mindstorm robot. The robot will be designed into a system where the user will be safe to enter the default password then the system will change the password every session. The results of the questionnaire showed that 81% users feel more secure, but more 60% said difficult to do because the user must perform the calculations in advance to enter the password.
Volume: 12
Issue: 3
Page: 689-694
Publish at: 2014-09-01

Multi-target Direction Measurement on Bistatic MIMO Radar

https://ijeecs.iaescore.com/index.php/IJEECS/article/view/3815
Jingfang Wang
In recent years, multiple-input multiple output (MIMO) radar has been widespread concern in the domestic and foreign researchers. Bistatic radar draws on the great success of MIMO technology in the communications field, and it has many advantages over conventional radar. In this paper, the direction angles estimations of bistatic MIMO radar are researched. To contrast traditional radar DOA estimates, the direction vector of the bistatic MIMO radar is the Knonecker plot of  the emission vector and reception  vector, that two-dimensional direction angles is estimated. To solve this problem, the principle of bistatic MIMO radar signal model is in-depthly researched.By proposing Capon dimensionality reduction method, the two-dimensional directions of the dual-based MIMO radar are estimated,  and computer simulation is to verify the effectiveness of the method.  http://dx.doi.org/10.11591/telkomnika.v12i9.4602 
Volume: 12
Issue: 9
Page: 6819-6826
Publish at: 2014-09-01

Forward Position Solution of 3-RPS in-Parallel Manipulator Based on Particle Swarm Optimization

10.11591/ijeecs.v12.i9.pp6758-6763
Hong Li Zhang , Tiantian Ren
Particle swarm optimization is introduced to solve the problem in this paper. Instead of solving a group of non-linear equations, forward kinematics is solved by computing the extrenum of a function. And accurate solutions can be obtained by the global and local searching abilities of advanced particle swarm optimization. It overcomes the shortage that precision is greatly influenced by initial values with conventional numerical methods. Calculation results show that this new method is simple, convenient, and with generality for solving the parallel manipulator forward kinematics problems.
Volume: 12
Issue: 9
Page: 6758-6763
Publish at: 2014-09-01

A Cognitive Radio Spectrum Sensing Algorithm to Improve Energy Detection at Low SNR

10.12928/telkomnika.v12i3.101
Agus; Institut Teknologi Bandung Subekti , Sugihartono; Institut Teknologi Bandung Sugihartono , Nana; Institut Teknologi Bandung Rachmana S , Andriyan; Institut Teknologi Bandung B.Suksmono
Energy detection is among the most popular spectrum sensing method for spectrum sensing due its low complexity. Unfortunately, its performance is poor at low SNR. In this paper we proposed a spectrum sensing method for cognitive radio network that improves the performance of energy detection. The proposed method based on distribution analysis using kurtosis as test statistic. This comes from the fact that distribution of received signal when a channel is occupied will be different from vacant channel. Noise tends to have a Gaussian distribution. Signal which faces multipath fading during the transmission way will have non Gaussian distribution. Sensing algorithm was tested using captured DTV signal. Result shows that our method performs well at low SNR. It achieves probability of detection of 90 % for 10 % Probability of false alarm for low SNR, below -20 dB.
Volume: 12
Issue: 3
Page: 717-724
Publish at: 2014-09-01

An improved Grey-based Approach for Short-Term Wind Power Prediction

10.11591/ijeecs.v12.i9.pp6502-6510
Bin Zeng , Hong-bing Xu , Jian-xiao Zou , Kai Li , Xiao-shuai Xin
With the expansion of wind farm installations in most countries all over the world, the power generation has already significantly influenced on the stability and security of the power grid after grid-connection. Wind power forecasting is an effective method for guarantees stability of the power output from wind farm. This paper proposed an improved GM (1,1)  based prediction method, and focuses on the wind power online prediction using the relationship between the wind speed and the wind power generation. The simulation results have verified that the developed approach, with GM rolling mechanism, data preprocessing and background value optimizing has better prediction precision over the traditional GM rolling model and data series smoothing model. Finally, utilized a case study at Azuoqi wind farm located in Inner Mongolia province of China, which obviously realized wind power generation prediction for optimizing the wind power control in the wind farm in real time.
Volume: 12
Issue: 9
Page: 6502-6510
Publish at: 2014-09-01

Reliability and Validaty of St George Respiratory Questionnaire (SGRQ) into Indonesian Version

10.11591/ijphs.v3i3.4691
Adnan Adnan , Dyah Aryani Perwitasari , Ully Adhie Mulyani
Tuberculosis (TB) is one of the disease as the highest contributor to the disease burden in Indonesia. Tuberculosis can affect the patients’ quality of life, such as psychological, physical, and social functioning. St. George's Respiratory Questionnaire (SGRQ) is a special instrument which was widely used to measure the patients’ quality of life with respiratory disease. The objective of this study was to validate the Indonesian version of the SGRQ as instrument to collect data. A descriptive cross section design with 61 subjects was conducted at the Pulmonary Clinics and Primary Health Centers in the region of Yogyakarta within 3 months. The validation process included the known group validity, convergent and discriminant validity and factor analysis. There were 14 items question numbers which did not meet the criteria for convergent validity and 9 items which did not meet the criteria for discriminant validity. Known group validity analysis on gender showed that of the three domains of SGRQ, the activity domain gave statistically significant result. The factor analysis showed the result of Kaiser Meyer Olkin analysis (KMO) was less than 0.5. With a few modifications, the Indonesian version of SGRQ is valid and reliable for measuring quality of life in tuberculosis patients.
Volume: 3
Issue: 3
Page: 179-184
Publish at: 2014-09-01
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