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Suatu Kajian Tentang Lapangan Kabur dan Ruang Vektor Kabur Muhammad Abdy; Syafruddin Side; Muhammad Edy Rizal
Journal of Mathematics, Computations and Statistics Vol. 1 No. 01 (2018): Volume 01 Nomor 01 (April 2018)
Publisher : Jurusan Matematika FMIPA UNM

Show Abstract | Download Original | Original Source | Check in Google Scholar

Abstract

This research redefine fuzzy fields and fuzzy linear spaces. Furthermore, we show some theorem that applies to both concepts of fields and linear spaces (classic and fuzzy concept).
Temperature Data Prediction in South Sulawesi Province Using Seasonal-Generalized Space Time Autoregressive (S-GSTAR) Model Rizal, Muhammad Edy; Fathan, Morina A.; Safitriani, Nur Rezky; Yahya, Muhammad Zarkawi; Asfar
JURNAL ILMIAH MATEMATIKA DAN TERAPAN Vol. 21 No. 2 (2024)
Publisher : Program Studi Matematika, Universitas Tadulako

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22487/2540766X.2024.v21.i2.17516

Abstract

Indonesia's distinct tropical climate is influenced by its geographic location near the equator and its complex topography, resulting in pronounced seasonal temperature patterns. This study examines the application of the Seasonal Generalized Space-Time Autoregressive (SGSTAR) model to forecast the average air temperature in four regions of South Sulawesi Province: North Luwu, Tana Toraja, Maros, and Makassar. The dataset comprises monthly average temperatures from January 2019 to October 2024, sourced from BMKG's online database. The analysis includes stationarity testing using the Augmented Dickey-Fuller (ADF) test, seasonal pattern identification with autocorrelation function (ACF), and formal seasonal tests such as QS, QS-R, and KW-R. Spatial weight matrices were constructed based on Euclidean distances between regions. The best model was selected based on Mean Square Error (MSE), Root Mean Square Error (RMSE), Akaike Information Criterion (AIC), and adjusted R² criteria. The findings reveal that the seasonal GSTAR model with AR orders (p=3), (ps=4), and (s=12) is the optimal model. Evaluation indicates that the model achieves high accuracy, with forecast errors (MSE and RMSE) below 1°C. This model effectively captures seasonal and spatio-temporal patterns in climate data. The study is expected to serve as a foundation for further development of seasonal GSTAR models for other climate datasets, supporting improved environmental planning and resource management.
Perbandingan Ukuran Jarak pada Analisis Kluster Hirarki Yahya, Muh. Zarkawi; Sitti Nurhaliza; Morina A Fathan; Muhammad Edy Rizal; Andi Harismahyanti A
Leibniz: Jurnal Matematika Vol. 5 No. 02 (2025): Leibniz: Jurnal Matematika
Publisher : Program Studi Matematika - Fakultas Matematika dan Ilmu Pengetahuan Alam Universitas San Pedro

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.59632/leibniz.v5i02.538

Abstract

Analisis klaster merupakan salah satu metode statistik untuk mengelompokkan objek berdasarkan kemiripan. Pada data kategorik, pemilihan ukuran jarak menjadi aspek penting karena memengaruhi struktur dan interpretasi klaster yang terbentuk. Penelitian ini bertujuan untuk membandingkan performa enam ukuran jarak Gower, Goodall1, Goodall2, Goodall3, Goodall4, dan Anderberg dalam analisis klaster hierarki menggunakan data kategorik dari Indonesian Family Life Survey (IFLS-5). Metode yang digunakan adalah hierarchical agglomerative clustering, dengan tahap awal pembersihan data dan konversi ke tipe faktor agar sesuai dengan karakteristik pengukuran jarak kategorik. Evaluasi hasil klaster dilakukan dengan dua indeks validasi internal, yaitu Silhouette dan Dunn, serta metrik eksternal Adjusted Rand Index (ARI) untuk menilai stabilitas klaster melalui proses bootstrapping. Ketiga metrik tersebut digunakan secara komplementer: Silhouette mengevaluasi konsistensi lokal anggota klaster (dengan nilai ? 0.5 umumnya dianggap baik), Dunn mengukur pemisahan antar-klaster secara global (semakin tinggi semakin baik), sementara ARI menunjukkan konsistensi struktur klaster terhadap variasi data (nilai mendekati 1 menunjukkan stabilitas tinggi). Hasil menunjukkan bahwa setiap ukuran jarak menghasilkan struktur klaster yang berbeda. Di antara semua ukuran yang diuji, Goodall4 memberikan hasil terbaik karena membentuk klaster yang mudah diinterpretasikan, memiliki nilai indeks Silhouette dan Dunn yang relatif tinggi, serta skor ARI mendekati sempurna. Hal ini mengindikasikan bahwa Goodall4 merupakan alternatif yang layak direkomendasikan dalam kasus serupa.
TIME SERIES IMPUTATION USING VAR-IM (CASE STUDY: WEATHER DATA IN METEOROLOGICAL STATION OF CITEKO) Rizal, Muhammad Edy; Wigena, Aji H; Afendi, Farit M
BAREKENG: Jurnal Ilmu Matematika dan Terapan Vol 16 No 4 (2022): BAREKENG: Journal of Mathematics and Its Applications
Publisher : PATTIMURA UNIVERSITY

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (851.852 KB) | DOI: 10.30598/barekengvol16iss4pp1373-1384

Abstract

Univariate imputation methods are defined as imputation methods that only use the information of the target variable to estimate missing values. While univariate imputation methods are convenient and flexible since no other variable is required, multivariate imputation methods can potentially improve imputation accuracy given that the other variables are relevant to the target variable. Many multivariate imputation methods have been proposed, one of which is Vector Autoregression Imputation Method (VAR-IM). This study aims to compare imputation results of VAR-IM-based methods and univariate imputation methods on time series data, specifically on long lag seasonal data such as daily weather data. Three modified VAR-IM methods were studied using simulations with three steps: deletion, imputation, and evaluation. The deletion step was conducted using six different schemes with six missing proportions. The simulations were conducted on secondary daily weather data collected from meteorological station of Citeko from January 1, 1991, to June 22, 2013. Nine weather variables were examined, that is the minimum, maximum, and average temperatures, average humidity, rainfall rate, duration of solar radiation, maximum and average wind speed, as well as wind direction at maximum speed. The simulation results show that the three modified VAR-IM methods can improve the accuracies in around 75% of cases. The simulation results also show that imputation results of VAR-IM-based methods tend to be more stable in accuracy as the missing proportion increase compared to the imputation results of univariate imputation methods.
Deepfake Image Classification Using ResNet50 Feature Extraction and XGBoost Learning Model Kusnaeni, Kusnaeni; Adriani, Ika Reskiana; Hafid, Mega Sartika; Andy B, Afif Budi; Rizal, Muhammad Edy
Journal of Mathematics, Computations and Statistics Vol. 8 No. 2 (2025): Volume 08 Nomor 02 (Oktober 2025)
Publisher : Jurusan Matematika FMIPA UNM

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.35580/jmathcos.v8i2.8387

Abstract

Deepfake is an artificial intelligence-based media manipulation technology that realistically fabricates a person's face, voice, and movements in both video and audio formats. The increasing use of deepfakes in the creation of various forms of deceptive content, including pornography, fake news, and fraud, has led to an urgent need for effective detection methods. One of the main challenges in detecting deepfakes is the high quality and realism of synthetic media, which renders conventional detection techniques less effective. Therefore, machine learning techniques capable of recognizing subtle patterns in visual data that are imperceptible to the human eye are required. This study aims to develop a deepfake image detection system using a hybrid machine learning approach that combines ResNet50 for feature extraction and XGBoost for classification. The pre-trained ResNet50 model, originally trained on the large-scale ImageNet dataset, is utilized to extract visual representations from images in the form of feature vectors. These features are then classified using XGBoost to distinguish between authentic and AI-generated images based on subtle patterns embedded within the extracted features. The results demonstrate that this hybrid approach achieves an accuracy of 94.6% in detecting deepfake images by leveraging the deep representation power of CNNs and the advanced classification capabilities of XGBoost. This method is not only computationally efficient but also highly relevant for integration into adaptive digital security systems.