The Improvement of Phonocardiograph Signal (PCG) Representation Through the Electronic Stethoscope

A conventional stethoscope (an acoustic stethoscope) is an acoustic medical device that is always used for preliminary examination of patients with any heart abnormalities. The main disadvantage of acoustic stethoscope is its dependence on how to use it and the experience of the examining physician. This paper presents a simple electronic stethoscope design in Phonocardiograph system that is free from subjectivity of doctors or other medical personnel. This electronic stethoscope is made sensitive in order to capture as many acoustic signal as possible from the activities of the human body, especially the heart and lungs. The design of this electronic stethoscope consists of chest piece, a pipe with proper acoustic impedance, mic condenser, mic preamp, and battery. The output of the mic preamp is connected to the mic channel on the laptop. The recording signal then processed separately. The repeatability of output signal was investigated in this paper. The signal was analyzed by using the Fast Fourier Transform (FFT). The result showed that the frequency responsea of the output signals are consistent, hence the instrument is reliable. Furthermore, the frequency response of the system with filter that connecting chest piece and mic condensor were also investigated

Steady-state response feature extraction optimization to enhance electronic nose performance

Feature extraction of electronic nose (e-nose) output response aims to reduce information redundancy so that the e-nose performance can be improved. The use of different sensor types and sample targets can affect the optimization of feature extraction. This research used six types of metal oxide sensors, TGS 813, 822, 825, 826, 2620, and 2611 in an e-nose system to detect three types of herbal drink. Five kinds of feature extraction methods on the original response curve in a steady-state response were used, namely, baseline difference, logarithmic difference, local normalization, global normalization, and global autoscaling. The results of feature extraction were fed into a Principal Component Analysis (PCA) system. As a result, global autoscaling and normalization had the highest total sum of the first and second principal components of 96.96%, followed by local normalization (90.18%), logarithm, and baseline difference (88.92% and 79.26%, respectively). The validation of PCA results was performed using a Backpropagation Neural Network (BPNN). The highest accuracy, 97.44%, was obtained from the global autoscaling method, followed by global normalization, local normalization, logarithm, and baseline difference, with an accuracy level of 94.87%, 92.31%, 89.74%, and 82.05%, respectively. This demonstrates that the selection of the feature extraction method can affect the classification results and improve e-nose performance

THE METHOD OF BASELINE MANIPULATION TO OVERCOME THE SENSOR DRIFT ON GAS SENSOR TEST FOR HERBAL DRINKS DISCRIMINATION

Abstract   Gas sensor system is widely used for the detection of aroma. The main problem in this system is the sensor drift that makes poor reproducibility of the sensor. The reproducibility of the sensor can be improved by applying the feature selection of the sensor’s output response and baseline manipulation. This research focused on determining methods that can reduce the dift sensor of gas sensor by using  basaeline manipulation and selecting the optimal type of baseline manipulation when gas sensor system detects three different types of herbal drinks. The data that have been feature selected were then applied to three different types of baseline manipulation (differential, relative and fractional) and inserted into the pattern recognition system, Principal Component Analysis (PCA). From the analysis of PCA baseline manipulation that gives optimal results is differential one with the value of PC1 82.71%. This shows that differential baseline manipulation is effective in reducing the occurrence of sensor drift.   Keywords: electronic nose, gas sensor, baseline manipulation, feature selectio

OPTIMASI TEKNIK PRAPEMROSESAN PADA RESPON LUARAN SENSOR UNTUK PENINGKATAN KLASIFIKASI PORTABLE ELECTRONIC NOSE: UJI COBA DISKRIMINASI JAMU

Portable electronic nose 4th generation (PEN4) had been developed in Universitas Gadjah Mada Material Physics and Electronics Instrumentation Laboratory. This PEN4 has had hardware part and data acquisition system, but not equipped with pattern recognition system yet. This research was focused on how to build a pattern recognition and classification system based on Principal Component Analysis (PCA) with preprocessing technique to equip PEN4. PEN4 then used to classify three kinds of herbal drink (kunir asem, beras kencur and temulawak). The optimization of preprocessing technique was done to produce the maximum classification result. From the optimization of three kinds preprocessing technique (baseline manipulation, Discrete Wavelet Transform (DWT), normalization), the DWT method of coif1 wavelet type in fourth, fifth and sixth level produced the highest first and second principal component. Cumulative percent of first and second principal component for fourth and fifth level reached 96%, level six reached 97%. Using this configuration, PEN4 was then used to classify the spoilage degree of the herbal drinks. The Total Plate Count as a method for counting the number of bacteria colony was used as a positive correlation probability confirmation of the existing bacteria in the drinks with the PCA result. The PCA patterns during 5 days of each herbal drink indicates that its aroma changed by time as a result of the spoilage process due to microorganisms. Therefore, the PEN4 may hold a promise as a herbal drinks spoilage degree assessments

FREQUENCY COMPONENT EXTRACTION OF HEARTBEAT CUES WITH SHORT TIME FOURIER TRANSFORM (STFT)

Abstract   Electro-acoustic human heartbeat detector have been made with the main parts : (a) stetoscope (piece chest), (b) mic condenser, (c) transistor amplifier, and (d) cues analysis program with MATLAB. The frequency components that contained in heartbeat. cues have also been extracted with Short Time Fourier Transform (STFT) from 9 volunteers. The results of the analysis showed that heart rate appeared in every cue frequency spectrum with their harmony. The steps of the research were including detector instrument design, test and instrument repair, cues heartbeat recording with Sound Forge 10 program and stored in wav file ; cues breaking at the start and the end, and extraction/cues analysis using MATLAB. The MATLAB program included filter (bandpass filter with bandwidth between 0.01 – 110 Hz), cues breaking with hamming window and every part was calculated using Fourier Transform (STFT mechanism) and the result were shown in frequency spectrum graph.   Keywords: frequency components extraction, heartbeat cues, Short Time Fourier Transfor

Pelatihan Penerapan Magnetic Generator Sebagai Sumber Energi Alternatif Bagi Masyarakat Kelurahan Giritontro, Kabupaten Wonogiri

Terbatasnya energi sumber daya mineral mempengaruhi ketersediaan listrik di berbagai pelosok Indonesia. Untuk mengatasi permasalahan ini, kelompok Pengabdian Kepada Masyarakat (PPM) kami membuat program pelatihan sumber energi listrik alternatif bagi masyarakat di daerah Kelurahan Girotontro, Kabupaten Wonogiri. Sumber energi listrik alternatif yang dibuat menggunakan akumulator sebagai penyedia daya d.c terhubung ke inverter sebagai pengubah transmisi d.c. ke a.c sehingga dapat menyalakan lampu. Masyarakat sangat antusias dalam mengikuti pelatihan dan juga dalam mencoba membuat sumber energi listrik alternatif karena dapat menjawab permasalahan listrik yang ada di daerah mereka

Pelatihan Biosand Filter Untuk Mengangani Masalah Kesadahan (Kadar Kapur) Dalam Air Minum Bagi Masyarakat Kelurahan Giritontro, Kabupaten Wonogiri

Sesuai dengan Peraturan Menteri Kesehatan RI No. 492/Menkes/Per/IV/2010 tentang Persyaratan Kualitas Air Minum, kesadahan dalam air layak minum tidak dapat lebih dari nilai baku mutu sebesar 500 mg/l. Tingginya kadar kapur didaerah Wonogiri yang dapat menyebabkan terganggunya kesehatan menimbulkan kesadaran masyarakat untuk mengolah air minum. Oleh karenanya dilakukan program pengabdian kepada masyarakat (PPM) di daerah kelurahan Giritontro, Kabupaten Wonogiri yang bertujuan mengangani masalah kesadahan (kadar kapur) dalam air minum dengan menggunakan Biosand Filter. Pada PPM ini, diperoleh hasil bahwa teknologi Biosand Filter dapat mengurangi tingkat kesadahan hingga 78%