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28,593 Article Results

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

Investigation of Distributed Search Engine Based on Hadoop

10.11591/ijeecs.v12.i9.pp6954-6957
Ning Chen , Chai Xiangyang
his paper begins with a review on the research status of search engine, followed by discussion on goals of search engine, and then the principle of distributed computing is explained. Consequently the MapReduce distributed computing model and the Hadoop distributed file system (HDFS) are analyzed in detail. Finally the distributed search engine architecture is presented. On the basis of the architecture, future challenges and opportunities of the distributed search engine are highlighted.
Volume: 12
Issue: 9
Page: 6954-6957
Publish at: 2014-09-01

Control Strategy Analysis on Preventive Maintenance

10.11591/ijeecs.v12.i9.pp6711-6724
Hong sheng Su , Yong qiang Kang , Juan di Li
ABSTRACTIn view of the limitations that the optimal examining item do not have dynamic real-time speciality and can’t reflect the actual state of devices in the traditional preventive maintenance(PM) model of repairable devices, in this paper a real-time control project on the checking rate of PM is proposed based on the state of devices. The differential equations used to describe the dynamic behavior of the system are established, and some performance indexes of maintenance systems including the steady-state availability, and the mean time to failure (MTTF), and as well as the average time of staying in each state are calculated. The control strategy on the checking rate is then proposed and the adaptability and the stability of the corresponding control system are analyzed. The essence of the method is to achieve the expected steady-state behavior by controlling the dynamic behavior of the system, which will ensure reliable completion of the task and reduce the maintenance cost meantime. Researches indicate that the proposed method is very effective to improve the utilization of devices and provide theoretical support for the practical applications.
Volume: 12
Issue: 9
Page: 6711-6724
Publish at: 2014-09-01

Do Males and Females Differ in Terms of Their KAP Regarding Halal Pharmaceuticals?

10.11591/ijphs.v3i3.4688
Saleha Sadeeqa , Azmi Sarriff
There is an increasing awareness amongst Muslim consumers to avoid all items containing  non-Halal ingredients including medications. Male and female are different both biologically and psychologically, it therefore, needed for a study to compare KAP of males and females regarding  Halal pharmaceuticals. Methods:This was a cross-sectional study using a structured , self-administered questionnaires to compare the knowledge, attitude & perception regarding Halal pharmaceuticals, among males and females in Penang state of Malaysia. Results revealed that there is no significance difference in the knowledge, attitude and perception of males and females. This is concluded that males and females are equally aware and have same attitude and perception regarding Halal pharmaceuticals. P value of .05 or less was taken as statistically significant.
Volume: 3
Issue: 3
Page: 163-168
Publish at: 2014-09-01

Error Analysis of ON-OFF and ANN Controllers Based on Evapotranspiration

10.11591/ijeecs.v12.i9.pp6771-6779
Susilo Adi Widyanto , Achmad Widodo , Achmad Hidayatno , Suwoko Suwoko
This paper presents error analysis of ON-OFF controller as well as ANN controller which is applied to an automated irrigation system. Controlling irrigation system was conducted  based on revised Penman-Monteith evapotranspiration and compared to a reference of soil moisture. Input parameters of the evapotranspiration included temperature, heat radiation, atmosphere pressure and wind speed. The output data of evapotranspiration was then used as input variable of ON-OFF controller as well as ANN controller. The performance of such controllers were evaluated and compared based on error of both controllers. The simulation results show that the error of the ON-OFF controller can be adjusted by setting the sampling time of the dead zone discretization. Error of ON-OFF controller with sampling time of 0.05 second is equal to error of ANN controller, that is 14.3% of reference signal amplitude.
Volume: 12
Issue: 9
Page: 6771-6779
Publish at: 2014-09-01

Predictors of Immunization Defaulting among Children Age 12-23 Months in Hawassa Zuria District of Southern Ethiopia: Community Based Unmatched Case Control Study

10.11591/ijphs.v3i3.4692
Fikru Tesfaye , Alemu Tamiso , Yemane Birhan , Tariku Tadele
As part of the overall package of maternal and child health services in Ethiopia, all children are provided with free immunization services and it is available in all government health facilities, both in rural and urban areas. But significant number of children was defaulted from Immunization schedule, even after the health extension program was launched. Therefore, the study was assessed predictors of immunization defaulting among children age range of 12-23 months, in Hawassa Zuria district of southern Ethiopia. Unmatched case control study was conducted in six Kebeles which were selected from 26 kebeles by simple random sampling techniques. Cases were children in the age ranges of 12 - 23 months who did not complete the recommended immunization. All cases (105) and controls (209) in the kebeles were identified by using health posts Vaccine registration book. Bivariable and multiple logistic regression model were used to identify important predictor of immunization defaulting. P-value of less than 0.05 was considered as the level of significances. The study identified educational status, place of delivery, immunization related knowledge, ANC follow up and household wealth status as significant predictors of defaulting from immunization schedules. Sustained health education on vaccination related knowledge and institutional delivery services utilization will be needed. The household literacy and economic status should also get emphasis so as to decreases defaulting of children from immunization schedule.
Volume: 3
Issue: 3
Page: 185-194
Publish at: 2014-09-01

Parity Early Stage of Marriage with Incidence of Postpartum Depression

10.11591/ijphs.v3i3.4687
Eny Retna Ambarwati , Ria Listiyani
Postpartum depression is a condition that may be experienced by women. If it is not addressed properly, it will have a negative impact. Determine the correlation between parity and the early stage of the marriage with the incidence of postpartum depression. This research used analytic observational method with cross sectional approach. The population in this research was postpartum mothers in Maternal Hospital Leonisa. The sampling was done using purposive sampling technique. The data analysis was done with univariate and bivariate analysis using Chi-square.The correlation between parity and the incidence of postpartum depression obtains the result of x2 count of 22.864 and p value of 0.000 with df2 and the significance level of (α) at 5% (0.05) x table at 5.591. Therefore, Ho is rejected and Ha is accepted. The correlation between the early stage of the marriage variable with the incidence of postpartum depression obtains a result of x2 count of 12.965 and p value of 0.000 with df 1, the significance level at 5% (0.05), x table at 3.481, therefore, Ho is rejected and Ha is accepted. There is a correlation between parity and the early stage of the marriage with the incidence of postpartum depression.
Volume: 3
Issue: 3
Page: 158-162
Publish at: 2014-09-01

Research on Some Key Problems of Self-exciting Electronic Ballast

10.11591/ijeecs.v12.i9.pp6437-6444
Peng Mao , Weiping Zhang , Mao Zhang
on the analysis of operation principles of conventional self-exciting electronic ballast, the cause of high switching loss has been researched. In order to reduce switch temperature and increase the reliability of the whole circuit, drive circuit of self-exciting electronic ballast has been improved to achieve soft switch. Circuit simulations and experimental results are coincided with the analysis of theory. In the end of this paper, the design procedure and winding method of self-excited transformer are introduced.  
Volume: 12
Issue: 9
Page: 6437-6444
Publish at: 2014-09-01

Epidemiological Characteristics of Poliomyelitis during the 21st century (2000-2013)

10.11591/ijphs.v3i3.4686
Tahir Ahmad , Sania Arif , Nazia Chaudry , Sadia Anjum
Poliovirus is the pathogenic agent of paralytic poliomyelitis that belongs to the picornaviridae family. Poliomyelitis has an extended history dating over to the Egyptian eighteenth dynasty. It was recognized as distinct disease in the late nineteenth century when the world was ravaged by large number of outbreaks and epidemics in many countries. Paralytic Polio, the rarest but the most severe form of the disease, is characterized by acute flaccid paralysis of any or rarely both of the limbs. Increasing epidemics during the late 19th and 20th centuries lead to the initiation of a worldwide global effort for polio eradication in 1988, super headed by WHO and various other organizations. The launch of Global Polio Eradication Initiative together with the introduction of two polio vaccines resulted in 99% reduction of wild poliovirus cases worldwide while the total number of polio-endemic countries dropped from 24 countries in the year 2000 to only three countries in 2012; Afghanistan, Nigeria and Pakistan. This review will focus on the general biology of poliovirus, some historic and geographic epidemiological aspects of poliomyelitis eradication during the year 2000-2012 and also on the major failing factors associated with the efficiency of the vaccines to eradicate polio in Pakistan.
Volume: 3
Issue: 3
Page: 143-157
Publish at: 2014-09-01
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