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All Journal International Journal of Power Electronics and Drive Systems (IJPEDS) TELKOMNIKA (Telecommunication Computing Electronics and Control) JURNAL ELEKTRO ELKOMIKA: Jurnal Teknik Energi Elektrik, Teknik Telekomunikasi, & Teknik Elektronika Proceeding of the Electrical Engineering Computer Science and Informatics Jurnal ELTIKOM : Jurnal Teknik Elektro, Teknologi Informasi dan Komputer Sinkron : Jurnal dan Penelitian Teknik Informatika CogITo Smart Journal MITRA: Jurnal Pemberdayaan Masyarakat Jurnal Mantik Jurnal Teknologi dan Manajemen Industri Terapan Jurnal Pengabdian Masyarakat Charitas Metris: Jurnal Sains dan Teknologi Cylinder : Jurnal Ilmiah Teknik Mesin
Bachri, Karel Octavianus
Universitas Katolik Indonesia Atma Jaya
Aerospace Engineering Humanities Computer Science & IT Control & Systems Engineering Decision Sciences, Operations Research & Management Economics, Econometrics & Finance Education Electrical & Electronics Engineering Energy Engineering Industrial & Manufacturing Engineering Languange, Linguistic, Communication & Media Materials Science & Nanotechnology Mechanical Engineering Public Health Social Sciences

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Analisis Penyebab Kecacatan Dengan Menggunakan Metode Seven Tools Pada Proses Perakitan Mesin Sepeda Motor Darmawan, Marten; Soewono, Arka Dwinanda; Wijaya, Nickolas Dario; Bachri, Karel Octavianus
Cylinder : Jurnal Ilmiah Teknik Mesin Vol 10 No 2 (2024): OKTOBER 2024
Publisher : Department of Mechanical Engineering Atma Jaya Catholic University of Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.25170/cylinder.v10i2.6001

Abstract

PT. SMT is a company that manufactures and distributes motorbikes. One of the main products assembled by PT. SMT is a 160 cc motorcycle engine. To improve the quality of the motorbike engine assembly process at PT. SMT, quality management based on the Seven Tools method has been performed. The check sheet analysis based on the production data from the January-July 2023 period shows that the most frequent quality issues in the engine assembly process are dirt on the cylinder inlet valve (64, 2%), followed by rust on the cylinder head (26.1%) and dirt on the gasket cover components for the cylinder head (9.8%). Root cause analysis using the Fishbone diagram finds that work environment factors including dirty workstations, equipment and components, as well as human factors are the main causes of product defects. From this analysis, the recommended improvements include implementing routine cleaning procedures for the work environment, equipment, and components, as well as providing additional training to improve operator competency and foster a better work culture.
PEMANTAUAN DAN PENGENDALIAN SUHU DAN KELEMBAPAN UDARA UNTUK TANAMAN TOMAT DENGAN MENGGUNAKAN WEMOS D1 Wijaya, Toby; Ghozali, Theresia; Bachri, Karel Octavianus
Cylinder : Jurnal Ilmiah Teknik Mesin Vol 11 No 1 (2025): April 2025
Publisher : Department of Mechanical Engineering Atma Jaya Catholic University of Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.25170/cylinder.v11i1.6190

Abstract

Plant cultivation process is an important component in creating optimal harvest results. Those results can be affected by both air temperature and humidity in the plant’s environment. Traditional method for monitoring and controlling temperature and humidity consume a lot of time and energy. This Wemos D1 and ThingSpeak equipped monitoring and controlling system was made in order to make those works easier. The system uses air temperature and humidity sensor which will perform reading to the environment’s condition. Datas collected from the reading progress will be forwarded by Wemos D1 to ThingSpeak so it can be observed by users. Exhaust fan and mist maker will be used as controlling components for the environment. This system is expected to help in developing plant cultivation techniques.
Analisis Performansi Jaringan Saraf Dalam terhadap Dataset Digit Berderau Bachri, Karel Octavianus
Jurnal Elektro Vol 18 No 1 (2025): Jurnal Elektro: April 2025
Publisher : Prodi Teknik Elektro, Fakultas Teknik Unika Atma Jaya Jakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.25170/jurnalelektro.v18i1.6613

Abstract

This work investigates the impact of noise on model performance by training a neural network on a digit dataset with varying Signal-to-Noise Ratios (SNR) to assess its resilience and generalization ability. The experimental setup involved training the model on datasets with noise levels ranging from clean images to highly distorted ones (SNR 5%–25%), analyzing accuracy, mini-batch loss, and training time. Results indicate that while the model achieves high accuracy (96.88%) at mild noise levels (SNR 5%), performance declines significantly at higher noise levels, with accuracy dropping to 78.91% at SNR 25%. The analysis of mini-batch loss and training time reveals that noise slows convergence and increases computational complexity. The confusion matrix further confirms that while the model effectively distinguishes between classes, noise-induced misclassifications become more frequent at lower SNRs. These findings emphasize the importance of noise reduction techniques and data preprocessing to improve model robustness in real-world applications.
Predicting transmission losses using EEMD – SVR algorithm Lestari, Hesti Tri; Sereati, Catherine Olivia; Siregar, Marsul; Bachri, Karel Octavianus
International Journal of Power Electronics and Drive Systems (IJPEDS) Vol 16, No 3: September 2025
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.11591/ijpeds.v16.i3.pp2122-2129

Abstract

This work introduces a predictive model for evaluating transmission losses in the Java-Bali electrical system using ensemble empirical mode decomposition (EEMD) and support vector regression (SVR) techniques. Transmission losses, a critical aspect of energy efficiency, are affected by several operational aspects, such as load flow, energy composition, peak load, and meteorological factors such as transmission line temperature. Transmission losses data were decomposed into many intrinsic mode functions (IMFs) by EEMD, effectively capturing both high-frequency (short-term) and low-frequency (long-term) trends. The SVR algorithm, utilizing a radial basis function (RBF) kernel, was subsequently employed to predict the deconstructed IMFs, facilitating accurate predictions of transmission losses. The proposed EEMD-SVR model achieved a mean absolute error (MAE) of 5.43%, with the highest error observed during the period of abrupt load shifts. These results confirm the model’s strength in identifying long-term transmission loss patterns, making it suitable for system planning and operational forecasting. While the model exhibited high prediction accuracy, especially in recognizing long-term trends, it faced limitations in accurately predicting abrupt changes in transmission losses. Therefore, future improvements should aim to enhance responsiveness to sudden changes in the system dynamics. The result suggests that the EEMD SVR model can proficiently assist power system operators in monitoring and mitigating transmission losses.
Implementasi dan Analisis Alat Kompres Demam Suhu Hangat dengan Sensor DS18B20 dan Pengendali Arduino Uno Bachri, Karel Octavianus; Soewono, Arka; Kevin
Jurnal Elektro Vol 17 No 2 (2024): Jurnal Elektro: Oktober 2024
Publisher : Prodi Teknik Elektro, Fakultas Teknik Unika Atma Jaya Jakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.25170/jurnalelektro.v17i2.5626

Abstract

Fever is a condition where the body temperature rises above normal levels, often caused by an infection. Non-medical management of fever can be done by using cold or warm compresses. Warm compresses are more effective but require a complex and repetitive process. This study is the design of a Digital Fever Compress Device using warm temperature based on Arduino Uno. The Digital Fever Compress Device is designed for non-medical fever management. The Digital Fever Compress Device is equipped with a DS18B20 sensor, Liquid Crystal Display (LCD), Relay, cartridge heater as a heating element, three pushbuttons, XL4005 stepdown module, and one On-Off switch. The Digital Fever Compress Device can produce warm temperatures and adjust them according to the user's preferences with a minimum limit of 37.5°C and a maximum of 42°C with a timer for 20 minutes. Environmental temperature affects the temperature setting processing carried out by the microcontroller. Based on the tests conducted in an air-conditioned room, the average time from the initial temperature to the setpoint is 6 minutes and 15 seconds, and the temperature increase from the setpoint ranges from 45.6°C or 15.079%. Meanwhile, testing in a non-air-conditioned room, the average time from the initial temperature to the setpoint is 2 minutes and 26 seconds, and the temperature increase from the setpoint ranges from 44.64°C or 12.37%.
Frequency Extraction of Phonocardiogram Signal using Fourier Transform Bachri, Karel Octavianus
Jurnal Elektro Vol 17 No 2 (2024): Jurnal Elektro: Oktober 2024
Publisher : Prodi Teknik Elektro, Fakultas Teknik Unika Atma Jaya Jakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.25170/jurnalelektro.v17i2.6195

Abstract

This article presents Fourier Transform application to extract features of Phonocardiogram Signals into its frequency components. Data was taken from Physionet Dataset of Phonocardiogram which comprises of normal and abnormal heart condition. Raw data was preprocessed using time clipping of 2 seconds at certain area that contains less noise. A lowpass filter was applied to denoise the raw signals. Experiments show the PCG of normal hearts has a dominant frequency of 50Hz to 150Hz, with the subdominant frequencies of 450 Hz to 650 Hz. The subdominant frequency of the normal hearts sometimes show anomaly with more amplitude compared to the dominant frequency.
Perbaikan Kondisi Keseimbangan Lintasan Produksi Dengan Penerapan Metode Genetic Algorithm Pada Lintasan Produksi Muffler K-59J PT XYZ Sutomo, Febryan; Hidayat, Trifenaus Prabu; Bachri, Karel Octavianus
Metris: Jurnal Sains dan Teknologi Vol. 23 No. 01 (2022): Juni
Publisher : Prodi Teknik Industri, Fakultas Teknik - Universitas Katolik Indonesia Atma Jaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.25170/metris.v23i01.2961

Abstract

PT. XYZ merupakan sebuah perusahaan manufaktur yang bergerak dibidang otomotif dan sudah berjalan sebagai supplier komponen otomotif untuk beberapa perusahaan otomotif terkemuka di Indonesia. Kebanyakan proses produksi pada PT. XYZ sudah berjalan dengan baik. Tetapi terdapat salah satu sub produk mereka yang memiliki kendala dalam proses produksinya yaitu muffler K-59J. Pada lintasan produksi muffler K-59J dinilai kurang optimal dalam proses produksinya. Hal tersebut dilihat dari banyak kendala yang timbul selama proses produksi berlangsung. Mulai dari terjadi penumpukan (bottleneck), Target produksi harian sering tidak tercapai sehingga sering terjadi waktu kerja tambahan (overtime), dan jika dilihat secara data nilai efisiensinya hanya sebesar 58,81 %. Dengan demikian, penelitian ini bertujuan untuk meningkatkan performa dari lintasan produksi tersebut. Oleh karena itu diusulkan metode Algoritma Genetik yang bersifat komputerisasi untuk meningkatkan performanya. Proses penyelesaian penelitian ini dilakukan dengan bantuan program matlab dalam pengerjaan metode Algoritma Genetik. Pada prosesnya, dilakukan beberapa tahapan mulai dari membuat representasi genetik, menyeleksi populasi induk, melakukan rekombinasi dan mutasi, dan regenerasi populasi. Tetapi terdapat sedikit perbedaan pada penlitian ini dimana populasi awal yang dibentuk merupakan populasi yang sudah tersaring kedalam syarat-syarat keseimbangan lintasan antara lain sesuai dengan diagram alurnya, dan jumlah waktu stasiun kerja tidak melebihi cycle time. Dari hasil pengerjaan metode Algoritma Genetik tersebut, didapatkan besar efisiensi lintasan sebesar 74,07 % dengan total stasiun kerja sebanyak 18 stasiun kerja. dengan demikian nilai efisiensi lintasan berhasil ditingkatkan sebesar 15,26 %.
Simulasi Pengendalian Kecepatan Putar Motor DC Menggunakan Metode Logika Fuzzy Hutapea, Duma Kristina Yanti; Sachi, Haenuki; Kusmanto, Willy; Herianto, David; Fernanto, Nico; Bachri, Karel Octavianus
Metris: Jurnal Sains dan Teknologi Vol. 24 No. 02 (2023): Desember
Publisher : Prodi Teknik Industri, Fakultas Teknik - Universitas Katolik Indonesia Atma Jaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.25170/metris.v24i02.4725

Abstract

This paper discusses DC motor rotational speed control using fuzzy logic method. The system works by utilizing ultrasonic sensors to detect distance. The detected distance affects the rotational speed of the DC motor which is controlled by the Arduino UNO microcontroller. Fuzzy logic is applied to the Arduino UNO microcontroller in which distance as the input, and the rotational speed of the DC motor in the form of Pulse Width Modulation as the output. There are several classifications of distance: very close, close, normal, far and very far. In addition, there are several classifications in the motor rotational speed response: slow, very slow, medium, fast, and very fast. The design of the fuzzy logic system is carried out in the Arduino IDE application and MATLAB using the Mamdani method at the inference stage. Fuzzy logic system is run on the Arduino UNO microcontroller in which the simulation is carried outthrough Proteus application. The test results show that the largest percentage of errors/discrepancies between the Proteus system design and the MATLAB is 1.55%. In the future, this simulation can be applied to systems such as self-driving cars.
Analisis Kekuatan Purwarupa Swing Arm Untuk Sepeda Motor Listrik: Studi Kasus Pada PT “SC” Bachri, Karel Octavianus; Soewono, Arka Dwinanda; Nabil, Alfi
Cylinder : Jurnal Ilmiah Teknik Mesin Vol 9 No 2 (2023): OKTOBER 2023
Publisher : Department of Mechanical Engineering Atma Jaya Catholic University of Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.25170/cylinder.v9i2.4982

Abstract

In recent years, the automotive industry has been experiencing a significant transition from internal combustion engines that use fossil fuels to electric vehicles. PT “SC” is one of the leading companies engaged in converting and developing electric vehicles in Indonesia. This research aims to conduct a strength analysis of the swing arm prototype developed by PT “SC”. Simulations were performed using SolidWorks software to determine the impact of static loading on the von Mises stress and strain experienced by the swing arm made from SS 400 material. The total load on the swing arm was 1610N based on the electric dynamo's weight and the possible passengers' weight on the electric motorbike. The stress analysis results show that the maximum and minimum Mises stresses ​​are 5.38 x 106 N/m2 and 1.99 x 10-1 N/m2, respectively. This stress produces a maximum displacement value of 4.54 x 10-3 mm. Calculation results from Solidworks found that the safety factor for the swing arm prototype was 43, meaning the design is safe to use.
Design and Implementation of Two-Axis Solar Tracker Bachri, Karel Octavianus; Wilson; Mulyadi, Melisa; Wijayanti, Linda; Hutapea, Duma Kristina Yanti; Siregar, Marsul
Cylinder : Jurnal Ilmiah Teknik Mesin Vol 9 No 2 (2023): OKTOBER 2023
Publisher : Department of Mechanical Engineering Atma Jaya Catholic University of Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.25170/cylinder.v9i2.4983

Abstract

Makalah ini membahas perancangan dan implementasi sistem penggerak panel surya 2 sumbu dengan menggunakan motor servo yang dikendalikan oleh mikrokontroler arduino uno, sistem ini bekerja berdasarkan masukan sensor LDR sebanyak empat buah yang dipasang pada masing-masing sisi panel surya dan satu buah yang dipasang di tengah modul solar panel tersebut.Sensor LDR pun dihubungkan pada mikrokontroller yang akan mengolah masukkan yang diberikan menjadi keluaran tegangan kepada motor servo.Motor servo yang dipakai diperancangan alat ini sebanyak dua buah yang akan meggerakkan panel surya menuju arah vertical dan horizontal. Pengujian dilakukan dengan beberapa tahap seperti pengujian hasil yang didapatkan oleh panel surya dengan berbagai kondisi,pengujian sensor cahaya dan pengujian keseluruhan.Sehingga mendapatkan hasil yang cukup baik dan memuaskan,kedua motor servo dapat bergerak menerima hasil keluaran yang diberikan oleh mikrokontroller dan kelima sensor LDR dapat menerima cahaya matahari dan mendeteksi arah cahaya matahari secara cukup baik sehingga perancangan alat mendapatkan hasil keseluruhan secara cukup baik. Hasil keseluruhan daya yang didapat secara maksimal oleh panel surya sebanyak 12V yang akan bergerak mengikuti arah cahaya matahari.
Co-Authors Adang Suwandi Ahmad Agi Tama Alexander, Justin Alvinson, Gregorius Anthon de Fretes, Anthon de Fretes Anthony , Jean Arwin Datumaya Wahyudi Sumari Bachtiar, Marsellinus Bambang Anggoro Soedjarno Bambang Iwan Suryana Bunardi, Marcelinus Eric Catherine Olivia Sereati Christine Natalia Duma Kristina Yanti Enny Widawati Erik Agustian Yulanda Fernanto, Nico Fortino, Antonius Edwin Hadikusuma, Ridwan Satrio Herianto, David Joko Tri Susilo Jonathan, Edoardo Karangga, Yusaphat Phosa Kartadinata, Budi Kelvin, Dimas Kevin Kevin kevin Khayam, Umar Kusmanto, Willy Lestari, Hesti Tri Lukas Maria Angela Kartawidjaja Marsellinus Bachtiar Wahju Marten Darmawan Melisa Mulyadi Micha Thesania Katarine Michael Deni Perdana Putera Nabil, Alfi Nova Eka Budiyanta Nur, Tajuddin Nuryana, Muhammad Risqi Osmond, Edbert Pandjaitan, Lanny W. PANJAITAN, LANNY Pardosi, Cristoni Hasiholan Paschalis, Sebastian Michael Paskalis, Yohanes Maria Jonathan Glenn PRAWIRA, WASKITO Putera, Michael Deni Perdana PUTRA, SADIANA Rizki Surya Permana Rory Anthony Hutagalung Sachi, Haenuki Sandra Octaviani Sandra Octaviani Satryanatha, Josaphat Febrian Setiawan, Axel Gilbert Siregar, Marsul Soewono, Arka Soewono, Arka D. Soewono, Arka Dwinanda Sutomo, Febryan Tajuddin Nur Theresia Ghozali Trifenaus Prabu Hidayat Veronica Windha Mahyastuty Wahju, Marsellinus Bachtiar Widodo Basuki Wijaya, Nickolas Dario Wijaya, Toby Wijayanti, Linda Wilson