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31,377 Article Results

Time frequency analysis of ultrasound doppler signal by s-transform and wigner-ville distribution

10.11591/ijeecs.v14.i3.pp1220-1227
Mahieddine Latfaoui , Fethi Bereksi Reguig
Ultrasound Doppler signal processing is a necessity in several disciplines of medicine. The interpretation of these signals allows a good diagnosis of patients in order to detect certain diseases. In this work, we will use different non-parametric time-frequency techniques such as the Wigner-Ville distribution (WVD), the Pseudo-Wigner-Ville distribution (PWVD), the smoothed pseudo Wigner-Ville distribution (SPWVD), and the S-transform in order to analyze the Ultrasonic Doppler signal of the femoral arteries.
Volume: 14
Issue: 3
Page: 1220-1227
Publish at: 2019-06-01

Formal expansion method for solving an electrical circuit model

10.12928/telkomnika.v17i3.10318
Tjendro; Sanata Dharma University Tjendro , Sudi; Sanata Dharma University Mungkasi
We investigate the validity of the formal expansion method for solving a second order ordinary differential equation raised from an electrical circuit problem. The formal expansion method approximates the exact solution using a series of solutions. An approximate formal expansion solution is a truncated version of this series. In this paper, we confirm using simulations that the approximate formal expansion solution is valid for a specific interval of domain of the free variable. The accuracy of the formal expansion approximation is guaranteed on the time-scale 1.
Volume: 17
Issue: 3
Page: 1338-1343
Publish at: 2019-06-01

Rain attenuation statistics for mobile satellite communications estimated from radar measurements in Malaysia

10.12928/telkomnika.v17i3.12040
Mohammad Ibrahim; Universiti Teknologi Malaysia Abozeed , Manhal; Universiti Teknologi Malaysia Alhilali , Lam Hong; Universiti Tun Hussein Onn Malaysia Yin , Jafri; Universiti Teknologi Malaysia Din
Mobile satellite communications will play a significant role in the next 5th generation mobile services. The use of high-frequency bands will be the enabler of this advancement. However, at high frequencies, excess rain attenuation causes severe signal losses and presents a major threat for the system availability, especially in the tropical region. To that end, this study presents the rain attenuation impact on mobile satellite communications estimated using long-term radar measurements in Malaysia, by exploiting the horizontal structure of rain from the radar database and simulating inner-city and highway mobile terminals scenarios. Additionally, a scaling factor was presented to scale available fixed satellite terminals measurements to mobile terminals operating at the same locality under similar conditions. In comparison to the available link measurements, the radar database was reliable enough to provide highly accurate estimates. In all simulation scenarios, the mobile terminal will depart the rainy area soon enough and experience lower attenuation statistics in comparison with the fixed terminal. The provided results will help determine the overall future system performance, especially in tropical regions.
Volume: 17
Issue: 3
Page: 1110-1117
Publish at: 2019-06-01

Community detection of political blogs network based on structure-attribute graph clustering model

10.11591/ijece.v9i3.pp2121-2130
Ahmed F. Al-Mukhtar , Eman S. Al-shamery
Complex networks provide means to represent different kinds of networks with multiple features. Most biological, sensor and social networks can be represented as a graph depending on the pattern of connections among their elements. The goal of the graph clustering is to divide a large graph into many clusters based on various similarity criteria’s. Political blogs as standard social dataset network, in which it can be considered as blog-blog connection, where each node has political learning beside other attributes. The main objective of work is to introduce a graph clustering method in social network analysis. The proposed Structure-Attribute Similarity (SAS-Cluster) able to detect structures of community, based on nodes similarities. The method combines topological structure with multiple characteristics of nodes, to earn the ultimate similarity. The proposed method is evaluated using well-known evaluation measures, Density, and Entropy. Finally, the presented method was compared with the state-of-art comparative method, and the results show that the proposed method is superior to the comparative method according to the evaluations measures.
Volume: 9
Issue: 3
Page: 2121-2130
Publish at: 2019-06-01

AACO technique for solving multiobjectives in electrical distribution system

10.11591/ijeecs.v14.i3.pp1076-1086
P. Ravi Babu , Srivani Molughu
The multi objectives in electrical distribution system are service restoration and minimization of Ohmic losses. These objectives can be achieved by artificial ant colony optimization through reconfiguration. Service restoration is also a major aspect for reliable service. If any fault occurs in the system, faulted zone is isolated from healthy system. This originates discontinuity in power supply. To maintain the continuity in power supply there is a necessity to provide service to these loads from adjacent healthy feeders through reconfiguration without infringement of radiality, load balance and critical parameters. In distribution system Ohmic losses are 30 to 40 percent. In order to minimize these losses, there is a need for reconfiguration of the system and perform the power flow analysis to get bus voltages, branch currents and power losses (i.e. real or Ohmic or copper loss and reactive power loss). A direct load flow analysis is adopted in the proposed work. In this paper four feeder test system used for service restoration and IEEE 33 bus, IEEE 69 bus test systems for minimization of Ohmic losses have been obtained.
Volume: 14
Issue: 3
Page: 1076-1086
Publish at: 2019-06-01

Cladding effects on silica directional couplers

10.12928/telkomnika.v17i3.8705
Ary; University al Azhar Indonesia Syahriar , Ahmad Husin; University al Azhar Indonesia Lubis , Jusman Syafii; University al Azhar Indonesia Jamal , Anwar; University al Azhar Indonesia Mujadin , Ahmad Juang; University al Azhar Indonesia Pratama
Directional couplers are widely used as passive and active optical devices in fibre and integrated optics, and form the basis of components such as switches, modulators and wavelength filters. They consist of two closely-spaced parallel waveguides, whose separation is sufficiently small that power may be transferred between the modes propagating in the two guides through an interaction involving their evanescent fields. In this paper results are presented for a range of near infrared single mode silica directional couplers fabricated by electron beam irradiation. The effects of over cladding layers will be highlighted. Changes on coupling coefficient due to different cladding refractive indexes will also be examined. The coupled mode theory will be employed to fit the experimental results with prediction by theory. It is found that over cladding layer alters the transmission characteristics of silica directional couplers.
Volume: 17
Issue: 3
Page: 1142-1148
Publish at: 2019-06-01

Effect of Ferroresonance on Wind Turbine: Comparison of Atp/Emtp and Matlab/Simulink

10.11591/ijeecs.v14.i3.pp1581-1594
Ajibola Akinrinde , Andrew Swanson , Remy Tiako
Different developers have produced several software packages as solutions to model electrical power systems for the purpose of carrying out diverse analyses to solve immediate and unforeseen problems in power systems. In this study, ATP/EMTP and Matlab/Simulink packages were compared in regards to their capability to give accurate results, time of simulation and ease of simulation when modeling DFIG wind turbine. Furthermore, ferroresonance caused by one stuck pole during switching operations were analyzed on both software. Characterization of resulting ferroresonance was done using Fast Fourier Transformation (FFT) analysis, phase plane diagram and Poincaré mapping. Chaotic mode ferroresonance was found in both ferroresonance events. However, ATP could only perform FFT analysis while other analyses were performed on Matlab/Simulink. There are differences in the results obtained from the two packages; overvoltage of 4.22 P.U. and 3.77 P.U. was experienced during opening and closing operation on ATP/EMTP model while 6.36 P.U. and 4.63 P.U. respectively was obtained on Matlab. However, ATP is faster in regards to time of simulation with CPU time of 110.58 secs and simulink simulation time was 130.81 secs. Finally, it was easier to carry out the simulation on Simulink.
Volume: 14
Issue: 3
Page: 1581-1594
Publish at: 2019-06-01

Significant variables extraction of post-stroke EEG signal using wavelet and SOM kohonen

10.12928/telkomnika.v17i3.11776
Esmeralda C.; Universitas Jenderal Achmad Yani Djamal , Deka P.; Universitas Jenderal Achmad Yani Gustiawan , Daswara; Universitas Jenderal Achmad Yani Djajasasmita
Stroke patients require a long recovery. One success of the treatment given is the evaluation and monitoring during recovery. One device for monitoring the development of post-stroke patients is Electroencephalogram (EEG). This research proposed a method for extracting variables of EEG signals for post-stroke patient analysis using Wavelet and Self-Organizing Map Kohonen clustering. EEG signal was extracted by Wavelet to obtain Alpha, beta, theta, gamma, and Mu waves. These waves, the amplitude and asymmetric of the symmetric channel pairs are features in Self Organizing Map Kohonen Clustering. Clustering results were compared with actual clusters of post-stroke and no-stroke subjects to extract significant variable. These results showed that the configuration of Alpha, Beta, and Mu waves, amplitude together with the difference between the variable of symmetric channel pairs are significant in the analysis of post-stroke patients. The results gave using symmetric channel pairs provided 54-74% accuracy.
Volume: 17
Issue: 3
Page: 1149-1158
Publish at: 2019-06-01

Exploring obstacles in language learning: Prospective primary school teacher in Indonesia

10.11591/ijere.v8i2.16700
Asrial Asrial , Syahrial Syahrial , Dwi Agus Kurniawan , May Subandiyo , Nur Amalina
In the implementation of educational practices, Indonesian is used as the language of instruction. Teacher candidates are prepared to have language competence as their knowledge in carrying out classroom learning. Important language competence is owned by a prospective elementary school teacher to facilitate communication with students and design learning about language. In an effort to improve material understanding and mastery of good language competence, prospective teachers in Primary School Teacher Education have constraints in the learning process in tertiary institutions that are identified based on 9 indicators. These indicators consist of curriculum, practicum activities materials/tools, books/modules, initial abilities of prospective teachers, learning resources from outdoor learning, learning resources from outdoor language learning, learning resources from indoor learning, learning environments, motivating teacher candidates, and the ability to judge yourself. This study uses a qualitative research approach. This study aims to analyze the constraints students face in Indonesian language competence. The sample in this study were students in Primary School Teacher Education with a total of 30 respondents. Data collection using interview and documentation techniques.
Volume: 8
Issue: 2
Page: 249-254
Publish at: 2019-06-01

Optimization of video steganography with additional compression and encryption

10.12928/telkomnika.v17i3.9513
Dwi; STIKOM PGRI Banyuwangi Arraziqi , Endi Sailul; State Politechnic of Banyuwangi Haq
Currently, data such as text, images and video are very important. Therefore, data must be secured from unauthorized parties. In this paper, we propose a number of security levels, first using compression techniques on the data that will be hidden to reduce the size of the data, second using encryption techniques on data that has been compressed so that data is more secure, third using video steganography techniques on compressed and encrypted data so that unauthorized parties are increasingly difficult to extract data. Measurement of differences in quality of cover-video and stego-video using MSE (Mean Square Error), PSNR (Peak Signal to Noise Ratio), evolution histogram of video tags, and video playback. The results show that the proposed algorithm gives better results than the previous algorithm which has a smaller MSE, larger PSNR, smaller histogram evolution of video tags, and play video without distortion.
Volume: 17
Issue: 3
Page: 1417-1424
Publish at: 2019-06-01

Authentication techniques in smart grid: a systematic review

10.12928/telkomnika.v17i3.11437
Malik; University for Technology Qasaimeh , Rawan; Princess Sumaya University for Technology Turab , Raad S.; Princess Sumaya University for Technology Al-Qassas
Smart Grid (SG) provides enhancement to existing grids with two-way communication between the utility, sensors, and consumers, by deploying smart sensors to monitor and manage power consumption. However due to the vulnerability of SG, secure component authenticity necessitates robust authentication approaches relative to limited resource availability (i.e. in terms of memory and computational power). SG communication entails optimum efficiency of authentication approaches to avoid any extraneous burden. This systematic review analyses 27 papers on SG authentication techniques and their effectiveness in mitigating certain attacks. This provides a basis for the design and use of optimized SG authentication approaches.
Volume: 17
Issue: 3
Page: 1584-1594
Publish at: 2019-06-01

Determinants of dietary adequacy among school age children in Guraghe Zone, Southern Ethiopia

10.11591/ijphs.v8i2.18365
Abdu Oumer Abdu , Berhanu Abebaw Mekonnen
Dietary diversity (DD) is a validated proxy indicator of micronutrient adequacy among different age groups including infants, children and women. This study assessed level of dietary adequacy and its associated factors among school age children in Guraghe Zone, Ethiopia. Survey was conducted among 769 children aged 6 to 12 years of with their care givers using multistage sampling method. Data were collected by using structured questionnaire containing the ten food groups for minimum dietary diversity for women and other parts. Adequate dietary diversity was categorized those children who consume at least five food groups. Bivariate and multivariable binary logistic regression with odds ratios (95% CI) was computed. Overall 769 children were included in the study, with a mean age of 8 years. The mean dietary diversity score was 4.9 (±1.42). About 444 (58.3%) had an inadequate dietary diversity. Those children from extended family size had 1.3 times to have inadequate DD level (AOR=1.3). Children from female headed households, did not attend formal education had 1.3 and 1.4 times higher odds of having an inadequate DD level (AOR=1.3 and 1.4). Similarly, children living with uneducated caregiver had six fold more likely to have an adequate DD level (AOR=6.7). The dietary diversity of children in the study area was below average. Household head, caregiver’s educational status, occupation of the household head, father/female headed household and family size were found to be associated with DD score. There should be awareness creation through existing Health extension platform and back yard vegetation should be improved.
Volume: 8
Issue: 2
Page: 211-218
Publish at: 2019-06-01

Toward semantic similarity measure between concepts in an ontology

10.11591/ijeecs.v14.i3.pp1356-1372
Suwan Tongphu , Boontawee Suntisrivaraporn , Pakinee Aimmanee
A similarity measure is one classical problem in Description Logic which aims at identifying the similarity between concepts in an ontology. Finding a hierarchy distance among concepts in an ontology is one popular technique. However, one major drawback of such a technique is that it usually ignores a concept definition analysis. This work introduces a new method for similarity measure. The proposed system semantically analyzes structures of two concept descriptions and then computes the similarity score based on the number of shared features. The efficiency of the proposed algorithm is measured by means of the satisfaction of desirable properties and intensive experiments on the Snomed ct ontology.
Volume: 14
Issue: 3
Page: 1356-1372
Publish at: 2019-06-01

PID-based temperature control device for electric kettle

10.11591/ijece.v9i3.pp1683-1693
Mohd Badril Nor Shah , Norfahaniza Zailany , Amar Faiz Zainal Abidin , Mohd Firdaus Halim , Khalil Azha Annuar , Arman Hadi Azahar , Muhamad Haniff Harun , Muhammad Faizal Yaakub
A normal electric kettle usually is intended to boil water until boiling point and cannot be controlled. Most of the kettle does not provide the temperature display for user to track the current temperature reading. Thus, this project is inspired from the shortcoming of most kettles that are sold at the market. By using Arduino microcontroller, a device is developed to control water temperature inside electric kettle. To provide automated temperature control, PID controller is chosen since it can provides precise water temperature control with less fluctuation. The device is also equipped with the display of the current water temperature and desired temperature. The device is tested to an electric kettle and the performance of PID controller in controlling water temperature is compared to on-off controller. An analysis is performed based on the amount of fluctuation with respect to desired temperature to verify the efficacy of the designed circuit and controller. It is found that the developed device and PID controller are capable to control the water temperature inside kettle based on the desired temperature set by user with less amount of fluctuation
Volume: 9
Issue: 3
Page: 1683-1693
Publish at: 2019-06-01

Lifetime enhancement for clustering protocols in heterogeneous wireless sensor networks

10.11591/ijeecs.v14.i3.pp1305-1314
Basim Abood , Yasser Kareem Al-Rikabi
In this paper, we propose a new clustering method called fuzzy stable election protocol (FSEP), which is capable to overcome the bottleneck problem and addressing the uneven energy consumption problem in heterogeneous WSNs. We also propose an energy-efficient routing method called particle swarm optimization routing method (PSORM) to find the optimal routing path for the heterogeneous WSNs. PSORM seeks to investigate the problems of balancing energy consumption and maximization of network lifetime. To demonstrate the effectiveness of FSEP-PSORM in terms of lessening end-to-end delay, balancing energy consumption, and maximization of heterogeneous network lifetime, we compare our method with three approaches namely, chessboard clustering approach, PEGASIS, and LEACH. Simulation results show that the network lifetime achieved by FSEP-PSORM could be increased by nearly 38%, 45%, and 60% more than that obtained by PEGASIS, LEACH and stable election protocol clustering (SEP), respectively.
Volume: 14
Issue: 3
Page: 1305-1314
Publish at: 2019-06-01
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