Journal of Mathematics: Theory and Applications

Perbandingan Model ARIMA dan Holt’s Double Exponential Smoothing Untuk Peramalan Harga Emas Indonesia 2025

2025-10-17T14:34:11+08:00

Perkembangan ekonomi dan pola pikir masyarakat telah menjadikan investasi sebagai salah satu usaha untuk mempersiapkan perekonomian di masa depan. Investasi emas merupakan salah satu alternatif investasi yang sederhana. Ketika nilai dolar turun, harga emas cenderung akan meningkat sehingga di tengah ketidakstabilan ekonomi global permintaan emas akan naik. Penelitian ini bertujuan untuk membandingkan model ARIMA (Autoregressive Integrated Moving Average) dan Holt’s Double Exponential Smoothing untuk peramalan harga emas Indonesia 2025. Data yang digunakan merupakan harga beli emas di Indonesia dari periode 1 Januari 2024 hingga 31 Desember 2024. Setelah dilakukan perbandingan, nilai Holt’s Double Exponential Smoothing memiliki nilai RMSE, MAE, dan MAPE yang lebih kecil dari Model ARIMA (0,1,3) sehingga model tersebut memiliki akurasi peramalan yang lebih tinggi dibandingkan model ARIMA.

Perbandingan Model Regresi Data Panel Untuk Analisis Umur Harapan Hidup Di Provinsi Lampung Tahun 2021-2023

2025-10-17T14:34:12+08:00

Umur Harapan Hidup adalah angka rata-rata tahun yang diharapkan bisa dijalani seseorang setelah mencapai usia tertentu. Umur Harapan Hidup digunakan sebagai indikator untuk mengevaluasi seberapa efektif pemerintah dalam meningkatkan kesejahteraan masyarakat secara keseluruhan, terutama dalam upaya meningkatkan kesehatan. Penelitian ini bertujuan untuk menentukan model regresi data panel terbaik, dengan model yang dibandingkan yaitu Common Effect Model (CEM), Fixed Effect Model (FEM), dan Random Effect Model (REM). Variabel yang digunakan terdiri dari Umur Harapan Hidup sebagai variabel dependen (Y), serta Rumah tangga memiliki sumber air minum layak (X₁), Rumah tangga memiliki akses hunian layak (X₂), dan Rumah tangga memiliki akses sanitasi layak (X₃) sebagai variabel independen yang mencakup 15 Kabupaten di Provinsi Lampung dari tahun 2021 hingga 2023. Hasil penelitian menunjukkan bahwa model terbaik adalah Random Effect Model (REM) dengan variabel independent yang signifikan berpengaruh terhadap umur harapan hidup (Y) adalah rumah tangga dengan akses sanitasi layak (X₃).

Classification of Regencies/Cities in South Sulawesi Province Based on Business Sectors Using Discriminant Analysis

2025-10-17T14:46:15+08:00

The purpose of this study is to use the Linear Discriminant Analysis (LDA) method to categorize districts and cities in South Sulawesi Province according to their main economic sectors. The Central Statistics Agency (BPS) of South Sulawesi provided data for the period 2019–2023. The dependent variable was classified according to GDP (GRDP) quartiles within economic sectors, while the independent variables were the Labor Force Participation Rate (LBFR), the Number of Business Units (NBE), and the Open Unemployment Rate (OUR). The findings indicate that the most important factors in group differentiation are TPA and TPT. The classification accuracy was only 37.5%, although the model met important assumptions such as normality, homogeneity of covariance, and the absence of multicollinearity. This suggests that the model should be further improved by adding more in-depth predictors or using more differentiated categorization techniques.

Clustering of Disaster Risk in Indonesian Regions Using Self-Organizing Maps and K-Means

2025-10-17T14:34:12+08:00

Indonesia is one of the countries with a high level of vulnerability to natural disasters, making accurate risk mapping essential to support mitigation planning. This study aims to cluster the provinces of Indonesia based on disaster occurrence characteristics using a hybrid approach of Self-Organizing Maps (SOM) and K-Means. The data were obtained from the Indonesian National Disaster Management Agency (BNPB), covering the frequency and types of disasters such as floods, extreme weather, eruptions, abrasion, earthquakes, forest/land fires, droughts, and landslides. The SOM representation results were clustered using K-Means, with the optimal number of clusters determined through the evaluation of the Davies–Bouldin index, Silhouette coefficient, and connectivity measure. The analysis revealed that two clusters provided the best separation: Cluster 1 includes most provinces with medium to low multi-hazard risk, while Cluster 2 consists of West Java, Central Java, and East Java, which have high hydrometeorological risk. This hybrid SOM and K-Means approach successfully identifies the spatial patterns of disaster risk and can serve as a reference for the government in formulating region-based mitigation strategies.

Optimal Strategy and Cost Effectiveness Analysis for Conservation of The Endangered Maleo: A Mathematical Approach

2025-10-17T14:34:13+08:00

Maleo is a large megapod found on the island of Sulawesi and surrounding islands and is an endangered species due to illegal hunting and habitat conversion. In this article, we propose a mathematical model for Maleo conservation. The model that is constructed is expressed as a system of ordinary differential equations consisting of five equations. To study the optimal strategy, we use optimal control theory. In our model there are three control parameters related to guarding Maleo nests, monitoring Maleo habitats, and transferring Maleo eggs to captivity. To measure the impact and the consequences of each intervention scheme, we determine the percentage increase in the Maleo population and the average cost-effectiveness ratio. Our results show that the most effective intervention scheme to increase Maleo populations is a combination of guarding Maleo nests, monitoring Maleo habitats, and transferring Maleo eggs to captivity. Meanwhile, the intervention scheme that has the best cost-effectiveness is the intervention scheme which is a combination of guarding Maleo nests and monitoring Maleo habitats.