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All Journal Jurnal Teknologi Dirgantara Jurnal Nasional Teknik Elektro dan Teknologi Informasi
Thomas Sri Widodo
Universitas Gadjah Mada
Aerospace Engineering Chemical Engineering, Chemistry & Bioengineering Computer Science & IT Control & Systems Engineering Electrical & Electronics Engineering Energy Engineering Mechanical Engineering Physics

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ALGORITMA DETEKSI SUDUT AZIMUT DAN ELEVASI ROKET MENGGUNAKAN SEMBILAN ANTENA ARRAY YAGI-UDA Satria Gunawan Zain; Adhi Susanto; Thomas Sri Widodo; Wahyu Widada
Jurnal Teknologi Dirgantara Vol 9, No. 1 Juni (2011)
Publisher : National Institute of Aeronautics and Space - LAPAN

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Abstract

 Radiation pattern of Yagi-Uda antenna is elliptical. This pattern can be used as a detector for the direction of the source of a radio emission. A total of nine Yagi-Uda antennas fitted with a 3x3 configuration. With this configuration, the measurement range for azimuth and elevation angles can reach 80º. The simulation was performed by using an antenna radiation pattern data. The number of antennas used for this simulation is nine. Then the data is merged into a 3x3 antenna configuration data. Based on data from nine antenna radiation patterns, the algorithm for the estimation of azimuth and elevation angles can be applied. Simulation results show that the measurement error of the signal without noise is close to zero. The algorithm used in this simulation can be applied to noise below 25%. Key word:Angle Estimation, Noise effects, Yagi-Uda Antennas, Rocket movement estimation
Analisis Perubahan Parameter Number of Signals Averaged (NSA) Terhadap Peningkatan SNR dan Waktu Pencitraan pada MRI Dwi Rochmayanti; Thomas Sri Widodo; Indah Soesanti
Jurnal Nasional Teknik Elektro dan Teknologi Informasi Vol 2 No 1: Februari 2013
Publisher : Departemen Teknik Elektro dan Teknologi Informasi, Fakultas Teknik, Universitas Gadjah Mada

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Abstract

A study about the influence of NSA shift to SNR to identify the existence of NSA shift to SNR and scan time had performed. The study aims to determine the alteration value of SNR when NSA was changed for every number and to obtain the NSA value which has more optimum image quality. The study was performed in Telogorejo Hospital at Semarang with MR modalities AirisII Hitachi 0.3 tesla by shifting NSA from 1 to 5 in cervical vertebrae (neck) sagittal T1 weighted with spin echo sequence. The SNR of five images were calculated with Matlab tool. SNR value was obtained by measuring the ROI at body of vertebra, spinal cord area and discus intervertebra to attain the signal average value. Experiment results show that the greater the NSA, the SNR is better and scan time is longer. SNR of the organ corpus, medulla spinalis and diskus intervertebra is increases from NSA 1 to 2 is 51%. When the NSA is raised to 3, the SNR increase is 89%, for NSA 4 the SNR increase is 99%, for NSA 5 the SNR increase is 102% . To get an SNR up to 100%, the NSA 4 is used. Meanwhile, to get images with good SNR and imaging duration is not long, the NSA 3 is used.
Penapisan Artifak Logam pada Citra CT-scan dengan Spatial Filter Andrey Nino Kurniawan; Thomas Sri Widodo; Indah Soesanti
Jurnal Nasional Teknik Elektro dan Teknologi Informasi Vol 2 No 1: Februari 2013
Publisher : Departemen Teknik Elektro dan Teknologi Informasi, Fakultas Teknik, Universitas Gadjah Mada

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Abstract

The metal artifact where are produced on CT image can covered some area near metal artifact so it obstructed to define pixel value (CT number), which in turn it is dificult to define between normal and pathological tissues on a-CT image so metal artifact are need to reduce for help a diagnose. This research’s aim was performed to reduce metal artifact on a-CT image.The method of this research is used spatial filtering with convolution technique where it aplicated to a-CT image with metal artifact and use image processing tool. A phantom with and without metal was scanned for to get an image data, and so CT image from patient where it have a metal artifact. The image data are filtering by seven filter where are different oneanother. Mean square error (MSE) was calculated to assessment performance of filters and a subjective assessment by the practitioners of CT-scan.Metal artifacts are generally formed from 2-3 pixels and has the shortest distance between metal artifacts beam of 2-3 pixels so that the filters used have a filter window size is 5 pixels. The results of filtered image in general has decreased in quality, and the results of assessment of respondents, the filter that has been chosen by the respondent is filter 2 is as much as 29.03% and 0,010703 of MSE value. Therefore we can conclude that the filter 2 is the best filter of the seven filters are used to reduce metal artifacts and still maintain the image quality of CT-scan on visualize organ that can still be used for diagnosis.
Akuisisi Data dan Pengolahan Isyarat Elektrokardiograf Menggunakan Modul USB Dataq DI-148U Henry Sulistyo; Thomas Sri Widodo; Maesadji Tjokronagoro; Indah Soesanti
Jurnal Nasional Teknik Elektro dan Teknologi Informasi Vol 2 No 1: Februari 2013
Publisher : Departemen Teknik Elektro dan Teknologi Informasi, Fakultas Teknik, Universitas Gadjah Mada

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Abstract

Heart signal data acquisition for the purpose of research is still an obstacle when using the standard ECG equipment from the manufacturer. The problem is the expensive equipment and the conversion of images into digital data. By using instrumentation amplifiers and electronic components in the market can be realized a simple ECG prototype by using interface Dataq DI-148U USB module for cardiac signals data acquisition.In this study, single channel ECG prototype realized with twelve leads by manually selected. Tests using five subjects that compared the results with standard hospital ECG equipment.From ECG prototype tests each sub section, the results are in accordance with the planning. The use of adhesive floating electrode type showed a smaller noise. IIR digital filter effectively reduces noise with SNR above of 20 dB and baseline wander at frequency cutoff 0.95 Hz. The threshold method is capable of detecting the peak R-R interval well to calculate the heart rate.
Analisis Klasifikasi Sinyal EKG Berbasis Wavelet dan Jaringan Syaraf Tiruan Arif Surtono; Thomas Sri Widodo; Maesadji Tjokronagoro
Jurnal Nasional Teknik Elektro dan Teknologi Informasi Vol 1 No 3: Agustus 2012
Publisher : Departemen Teknik Elektro dan Teknologi Informasi, Fakultas Teknik, Universitas Gadjah Mada

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Abstract

ECG signals analysis at first associated to pattern recognition of the ECG signals marphology. Nonetheless the signals marphology varying not only in different patients but also in the same patient. The varying of the ECG marphology has efected difficulties in ECG analysis, particularly for a trainingless medicines. On the other hand the ECG signals contain much noises. Therefore it was require the suitable methods for ECG signals analysis. This research aim are analyzing and classifying of the ECG signals from heart condition of normal, arrhytmia, ventricular tachyarrhytmia, intracardiac atrial fibrillation dan myocard infarction based on wavelet transformation and artificial neural network backpropagation.The research stages are data preparing, pre-processing, feature extraction, processing and post-processing. The 60/50 Hz noises in ECG signals from power line interference reduced using IIR notch filter with pole-zero placement method. The baseline wander noises reduced using discrete wavelet transform of 11 level decomposition to find frequency component below 0,5 Hz as a noise source.Based on this work results obtained that average accuracy percentage of the neural network recognized all of the ECG types reached 87,424 %. Highest accuracy percentage of 95,455 % for ventricular tachyarrhytmia and lowest accuracy percentage of 70 % for arrhytmia classification.
Co-Authors Adhi Susanto Andrey Nino Kurniawan Dwi Rochmayanti Henry Sulistyo Indah Soesanti Maesadji Tjokronagoro Maesadji Tjokronagoro Satria Gunawan Zain Surtono, Arif Wahyu Widada