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All Journal Seminar Nasional Aplikasi Teknologi Informasi (SNATI) Semantik Jurnal Teknologi Informasi dan Ilmu Komputer Seminar Nasional Informatika (SEMNASIF) JOIV : International Journal on Informatics Visualization Jurnal RESTI (Rekayasa Sistem dan Teknologi Informasi) JURNAL MEDIA INFORMATIKA BUDIDARMA JURNAL TEKNIK INFORMATIKA DAN SISTEM INFORMASI JURIKOM (Jurnal Riset Komputer) Aptisi Transactions on Technopreneurship (ATT) Building of Informatics, Technology and Science Journal Sensi: Strategic of Education in Information System Jurnal Sistem Komputer dan Informatika (JSON) Aiti: Jurnal Teknologi Informasi Jurnal Indonesia : Manajemen Informatika dan Komunikasi Jurnal Ilmiah Sains Magistrorum et Scholarium: Jurnal Pengabdian Masyarakat IT-Explore: Jurnal Penerapan Teknologi Informasi dan Komunikasi Jurnal Indonesia : Manajemen Informatika dan Komunikasi Jurnal DIMASTIK
Theopillus J. H. Wellem
Universitas Kristen Satya Wacana
Agriculture, Biological Sciences & Forestry Humanities Biochemistry, Genetics & Molecular Biology Chemistry Computer Science & IT Control & Systems Engineering Decision Sciences, Operations Research & Management Economics, Econometrics & Finance Education Electrical & Electronics Engineering Engineering Languange, Linguistic, Communication & Media Law, Crime, Criminology & Criminal Justice Library & Information Science Mathematics Physics Social Sciences Other

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STUDI MODUL WIFI DAN SIMULASI JARINGAN IEEE 802.11AX PADA SIMULATOR NS-3 UNTUK PENGUKURAN THROUGHPUT Maulana, Aldias Henry; Wellem, Theophilus
IT Explore: Jurnal Penerapan Teknologi Informasi dan Komunikasi Vol 3 No 3 (2024): IT-Explore Oktober 2024
Publisher : Fakultas Teknologi Informasi, Universitas Kristen Satya Wacana

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24246/itexplore.v3i3.2024.pp296-308

Abstract

IEEE 802.11ax WiFi 6 is the current standard for wireless local area network (WLAN) technology which is a development of the previous standard, namely IEEE 802.11ac (WiFi 5). WiFi 6 has new features that are superior to WiFi 5. For example, it can operate in the 6 GHz frequency band, use 1024-QAM modulation, and use a maximum of 8 spatial streams. In general, to test and verify the implementation of a network technology standard, researchers can buy hardware on the market that has implemented the standard in its entirety or only certain mandatory features. Apart from using hardware directly, testing can also be done using software simulations. This research aims to study the WiFi model in the ns-3 simulator and simulate the IEEE 802.11ax WiFi 6 network. The simulation is carried out to measure the uplink throughput that can be achieved by WiFi 6 with various numbers of client stations (STA) and various distances between the Access Point (AP) and STA. The simulation results show that the throughput value will decrease with increasing AP-STA distance and the number of STA. The maximum throughput value obtained in the simulation with 5 STA at a distance of 2 meters from the AP is 655.41 Mbps.
Multi-Objective k-Nearest Neighbor for Breast Cancer Detection Nataliani, Yessica; Arthur, Christian; Wellem, Theophilus; Hartomo, Kristoko Dwi; Wahab, Nur Haliza Abdul
JOIV : International Journal on Informatics Visualization Vol 9, No 1 (2025)
Publisher : Society of Visual Informatics

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.62527/joiv.9.1.2669

Abstract

Early detection of cancer is crucial. This study aims to increase the efficiency of breast cancer detection using the modified k-nearest neighbor (k-NN) algorithm. Since k-NN faces challenges with sensitivity to k values and computational complexity, a modification of k-NN was proposed, namely a multi-objective k-NN model. It was developed to incorporate multi-objective optimization and local density to create a more robust and efficient classification algorithm. The model dynamically determines the k value based on the sample density, optimizing accuracy and efficiency. Breast cancer data were collected from the University of Wisconsin Hospitals, Madison. The experimental results showed that the multi-objective k-NN model outperformed traditional k-NN and k-NN with feedback support. The proposed model achieved an accuracy of 93.7%, with precision values of 93% for the negative cancer class and 94% for the positive cancer class. These results indicate that the multi-objective k-NN model provides superior accuracy and precision in breast cancer detection, demonstrating its potential for clinical applications.
Optimizing Multilayer Perceptron with Cost-Sensitive Learning for Addressing Class Imbalance in Credit Card Fraud Detection Priatna, Wowon; Hindriyanto Dwi Purnomo; Ade Iriani; Irwan Sembiring; Theophilus Wellem
Jurnal RESTI (Rekayasa Sistem dan Teknologi Informasi) Vol 8 No 4 (2024): August 2024
Publisher : Ikatan Ahli Informatika Indonesia (IAII)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.29207/resti.v8i4.5917

Abstract

The increasing use of credit cards in global financial transactions offers significant convenience for consumers and businesses. However, credit card fraud remains a major challenge due to its potential to cause substantial financial losses. Detecting credit card fraud is a top priority, but the primary challenge lies in class imbalance, where fraudulent transactions are significantly fewer than non-fraudulent ones. This imbalance often leads to machine learning algorithms overlooking fraudulent transactions, resulting in suboptimal performance. This study aims to enhance the performance of Multilayer Perceptron (MLP) in addressing class imbalance by employing cost-sensitive learning strategies. The research utilizes a credit card transaction dataset obtained from Kaggle, with additional validation using an e-commerce transaction dataset to strengthen the robustness of the findings. The dataset undergoes preprocessing with RUS and SMOTE techniques to balance the data before comparing the performance of baseline MLP models to those optimized with cost-sensitive learning. Evaluation metrics such as accuracy, recall, F1 score, and AUC indicate that the optimized MLP model significantly outperforms the baseline, achieving an AUC of 0.99 and a recall of 0.6. The model's superior performance is further validated through statistical tests, including Friedman and T-tests. These results underscore the practical implications of implementing cost-sensitive learning in MLPs, highlighting its potential to significantly enhance fraud detection accuracy and offer substantial benefits to financial institutions.
Pemodelan Pengaruh E-Learning Pada Performa Akademik Mahasiswa Dengan Technology Acceptance Model Dan Analisis Structural Equation Modelling Daniawan, Benny; Wijono, Sutarto; Manongga, Danny; Sembiring, Irwan; Krismiyati, Krismiyati; Wellem, Theophilus
Jurnal Teknologi Informasi dan Ilmu Komputer Vol 12 No 3: Juni 2025
Publisher : Fakultas Ilmu Komputer, Universitas Brawijaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.25126/jtiik.2025128229

Abstract

E-learning telah menjadi alat yang penting dalam pendidikan tinggi, memungkinkan perguruan tinggi untuk menyediakan aksesibilitas dan fleksibilitas dalam pengajaran dan pembelajaran. Salah satu platform e-learning yang populer adalah Moodle yang digunakan oleh banyak universitas di indonesia. Namun, penggunaan Moodle di universitas belum banyak diteliti secara mendalam, terutama dalam konteks pengaruh e-learning terhadap indeks prestasi akademik. Oleh karena itu, penelitian ini bertujuan untuk melakukan pengujian e-learning Moodle di lingkungan Universitas Buddhi Dharma yang berlokasi di Tangerang dengan metode Technology Acceptance Model (TAM) menggunakan lima variabel Perceive Usefulness (PU), Perceive Ease of Use (PEOU), Attention Towards Using (ATU), Behaviour Intention to Use (BITU), dan Actual System Using (ASU) ditambah dengan dua variabel lain yaitu Level of Confidence (LC) dan Academic Performance (AP). Seluruh variabel dianalisis menggunakan Structural Equation Modelling (SEM). Hasilnya menunjukkan bahwa persepsi kemudahan penggunaan (PEOU), dan persepsi kebermanfaatan (PU) memiliki pengaruh positif secara signifikan terhadap sikap (ATT) dan niat perilaku pengguna (BITU) serta aktual penggunaan sistem (ASU) dalam Moodle sebagai platform e-learning dengan nilai t-statistik yang melebihi nilai t-tabel dan p-value. Namun dalam hal ini penerimaan teknologi e-learning yang baik tidak mempengaruhi tingkat kepercayaan diri (LC) dan performa akademik pengguna (AP) secara aktual.   Abstract E-learning has become an essential tool in higher education, enabling universities to provide accessibility and flexibility in teaching and learning. One of the popular e-learning platforms is Moodle, which many universities in Indonesia use. However, the use of Moodle at universities has yet to be studied in depth, especially in the context of the influence of e-learning on the academic performance index. Therefore, this research aims to test Moodle e-learning in the Buddhi Dharma University environment located in Tangerang using the Technology Acceptance Model (TAM) method using the five variables Perceive Usefulness (PU), Perceive Ease of Use (PEOU), Attention Towards Using (ATU), Behavioral Intention to Use (BITU), and Actual System Using (ASU) plus two other variables, namely Level of Confidence (LC) and Academic Performance (AP). All variables were analyzed using Structural Equation Modeling (SEM). The results show that perceived ease of use (PEOU) and perceived usefulness (PU) have a significant positive influence on attitudes (ATT) and user behavioral intentions (BITU) as well as actual system use (ASU) in Moodle as an e-learning platform with a value of t -statistics that exceed the t-table value and p-value. However, in this case, a good acceptance of e-learning technology does not affect the Confidence Level (LC) and user Academic Performance (AP).
Academic Document Authentication using Elliptic Curve Digital Signature Algorithm and QR Code Wellem, Theophilus; Nataliani, Yessica; Iriani, Ade
JOIV : International Journal on Informatics Visualization Vol 6, No 3 (2022)
Publisher : Society of Visual Informatics

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.62527/joiv.6.3.872

Abstract

Paper-based documents or printed documents such as recommendation letters, academic transcripts, and diplomas are prone to forgery. Several methods have been used to protect them, such as watermarking, security holograms, or using paper with specific security features. This paper presents a document authentication system that utilizes QR code and ECDSA as the digital signature algorithm to protect this kind of document from counterfeiting. A digital signature is a well-known technique in modern cryptography used for providing data integrity and authentication. The idea proposed herein is to put a QR code in the printed documents where the QR code includes a digital signature. The signature can later be authenticated using the proposed system by uploading the document for authentication or scanning the document's QR code. The proposed system is particularly developed for digital signature generation and verification of students' final project approval documents as the case study. In traditional settings, the approval form is typically signed directly by the student's advisor dan co-advisor using handwritten signatures. However, using the conventional handwritten signature, the signature on the approval form can be falsified. Therefore, a digital signature generation and verification system is implemented herein to avoid handwritten signature falsification. The advisors can use this system to sign the approval form using a digital signature instead of a handwritten one. The signature is stored in a QR code and is generated using ECDSA with SHA-256 as the hash function. The proposed system is evaluated using documents (i.e., approval forms) with genuine and forged QR codes.  The evaluation results showed that the system could verify the authenticity of the approval forms, which contain genuine QR codes. The approval forms that contained forged QR codes were correctly identified.
PENGENALAN GAME EDUKASI BAGI SISWA TK KRISTEN 1 SATYA WACANA SALATIGA USIA 5-6 TAHUN Anton Hermawan; Nataliani, Yessica; Hindriyanto Dwi Purnomo; Christianto, Erwien; Atik Setyanti, Angela; Yulia, Hanita; Krismiyati; Juliastomo Gundo, Adriyanto; Wellem, Theophilus; Hendry
Jurnal DIMASTIK Vol. 3 No. 2 (2025): Juli
Publisher : Universitas Semarang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.26623/dimastik.v3i2.12302

Abstract

Kemajuan teknologi informasi dan komunikasi menuntut adanya adaptasi dalam dunia pendidikan, termasuk pada jenjang pendidikan anak usia dini. Pengenalan teknologi sejak dini menjadi langkah strategis dalam membentuk kesiapan anak menghadapi era digital. Kegiatan pengabdian ini bertujuan untuk mengenalkan teknologi, khususnya komputer, kepada siswa Taman Kanak-kanak (TK) melalui game edukasi berbasis online. Kegiatan dilaksanakan secara luring di TK Kristen 1 Satya Wacana, Salatiga, dengan melibatkan siswa berusia 5–6 tahun. Metode pelatihan dilakukan dalam beberapa sesi, mencakup pengenalan bagian-bagian komputer, penggunaan mouse, serta pelatihan melalui game edukasi seperti pengenalan huruf, angka, bentuk geometri, dan jenis-jenis kendaraan. Hasil evaluasi menunjukkan bahwa siswa menunjukkan antusiasme tinggi selama pelatihan, serta mulai mengenal komputer sebagai media pembelajaran alternatif selain perangkat yang biasa digunakan di rumah seperti handphone dan tablet. Kegiatan ini membuktikan bahwa pendekatan belajar sambil bermain dengan teknologi dapat meningkatkan minat belajar dan keterampilan dasar siswa dalam menggunakan komputer.
Co-Authors Ade Iriani Adi Setiawan Adriyanto Juliastomo Gundo Agustinus Fritz Wijaya Antika Lorien Anton Hermawan Arthur, Christian Atik Setyanti, Angela Bentar Priyopradono Danang Maulana Ikhsan Daniawan, Benny Daniel D Kameo Danny Manongga Darmawan Utomo Donny Priyadi Edi Suharyadi Erwien Christianto Fauzan, Rafi Ardhan Fra Arsandy Kusuma Sejati Fransiscus Bryan Prasetio Gabriel Gracia Salindeho Hanita Yulia Henderi . Hendry Hindriyanto Dwi Purnomo Ignatius Agus Supriyono Ikhsan, Danang Maulana Ilham Hizbuloh Imanuel Susanto Indrastanti Ratna Widiasari Irwan Sembiring Ivanna Kristianti Timotius Iwan Setyawan Jonathan Putera Perdana Krismiyati Kristoko Dwi Hartomo Lasso, Aldi Luis Geraldo Mauboy Maulana, Aldias Henry Muhamad Yusup Pantow, Prayogo Pangestu Piter Wijaya Prakoso, Alvian Dafa Priatna , Wowon Putra, Yeheskiel Mandala Rafi Ardhan Fauzan Rafly Fernanda Rizky Restu Fauzi Roland Tumbelaka Palar Sri Yulianto Joko Prasetyo Suharyadi Sutarto Wijono Tintien Koerniawati Valen Brata Pranaya Wahab, Nur Haliza Abdul Weku, Winsy C.D Yeheskiel Mandala Putra Yessica Nataliani Yonas Juniantiko Putro