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A Comparison of Multivariate Adaptive Regression Spline and Spline Nonparametric Regression on Life Expectancy in Indonesia Pratama, Bagas Shata; Suliyanto, Suliyanto; Mardianto, M. Fariz Fadillah; Sediono, Sediono
JTAM (Jurnal Teori dan Aplikasi Matematika) Vol 9, No 3 (2025): July
Publisher : Universitas Muhammadiyah Mataram

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.31764/jtam.v9i3.29413

Abstract

Life expectancy is a key indicator of a population’s overall health and well-being. It also reflects the effectiveness of government efforts in improving public welfare. Despite various initiatives by both the government and society to improve life expectancy in Indonesia, significant disparities remain. This quantitative study aims to support these efforts by analyzing factors influencing life expectancy in Indonesia using data from the Indonesian Central Agency of Statistics (BPS) in 2023. A comparative analysis was conducted using two methods: Multivariate Adaptive Regression Spline (MARS) and Spline Nonparametric Regression. The results show that the MARS model outperforms the Spline model, achieving a lower Mean Squared Error (MSE) of 1.183 and a higher R-Square of 82.7%. Key variables significantly influencing life expectancy include access to decent housing, access to safe drinking water, per capita expenditure, and the Gini ratio. The findings not only confirm the presence of complex interactions among predictor variables effectively captured by the MARS method, but also contribute to the existing literature by emphasizing the importance of socioeconomic determinants in health outcomes. From a policy perspective, the results suggest that government strategies should prioritize improving access to basic needs and reducing inequality. These insights can guide targeted, data-driven interventions aimed at enhancing life expectancy in Indonesia.
Modeling Prevalence of Hypertension in Indonesia with Multivariate Adaptive Regression Splines Method Suliyanto, Suliyanto; Saifudin, Toha; Naura, Sheila Sevira Asteriska; Dewanty, Sanda Insania; Wulandari, Indana Zulfa; Aflaha, Nabila Shafa; Aulia, Niswa Faizah
JTAM (Jurnal Teori dan Aplikasi Matematika) Vol 9, No 2 (2025): April
Publisher : Universitas Muhammadiyah Mataram

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.31764/jtam.v9i2.28392

Abstract

Hypertension is one of the important public health problems in Indonesia, which contributes to the high prevalence of non-communicable diseases. This study aims to model the prevalence of hypertension in Indonesia using the Multivariate Adaptive Regression Splines (MARS) method to identify significant predictors and their interactions. The data used was secondary data from the 2023 Indonesian Health Survey, including variables such as smoking prevalence, physical inactivity, dietary habits (consumption of fatty and sweet foods), lack of fruit and vegetable consumption, and obesity prevalence. The MARS method was used to analyse the nonlinear relationships and interactions between these predictors. After a trial-and-error process to determine the optimal number of basis functions (BF), maximum interactions (MI), and minimum observations (MO), the best model was achieved with BF = 18, MI = 3, and MO = 1. This model produced a Generalised Cross Validation (GCV) value of 13.428 and R-Square of 0.278. This fairly low R-Square value indicates that the factors analysed have contributed to the variation in hypertension prevalence, but there are still other aspects that can be taken into account to improve the predictive power of the model. The significant predictor variables were consumption of fatty foods (X3), lack of physical activity (X2), and consumption of sweets (X4), with the highest importance on X3 (100%). The findings reveal that interactions between variables, such as dietary habits and physical inactivity, significantly influence the prevalence of hypertension. For example, higher consumption of fatty and sweet foods combined with low physical activity increases the risk of hypertension. These results demonstrate the effectiveness of the MARS method in capturing complex and nonlinear relationships and serve as findings that highlight the need for health policies that focus on healthy diets and increased physical activity, in line with Goal 3 of the SDGs, “Good Health and Well-Being,” which aims to reduce premature mortality from noncommunicable diseases. Recommended interventions include nutrition education campaigns and community-based exercise programs to reduce the prevalence of hypertension in Indonesia.
Pemodelan Indeks Kualitas Lingkungan Hidup di Indonesia dengan Spline Truncated dan MARS Fitri, Marfa Audilla; Suliyanto, Suliyanto; Mardianto, M Fariz Fadillah; Ana, Elly
Jurnal Statistika dan Komputasi Vol. 4 No. 1 (2025): Jurnal Statistika dan Komputasi
Publisher : Universitas Nahdlatul Ulama Sunan Giri

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.32665/statkom.v4i1.4394

Abstract

Background: Indonesia, endowed with abundant natural resources, faces substantial challenges in maintaining environmental quality amid rapid urbanization and economic growth. The 2022 Environmental Performance Index ranked Indonesia 164th out of 180 countries with a score of 28.2. Regionally, Indonesia ranked 22nd among 25 Asia-Pacific countries. The Environmental Quality Index (EQI), crucial for achieving the Sustainable Development Goals (SDGs), was recorded at 72.42 in 2022, classified as "fair." This condition underscores the need for in-depth analysis of key factors influencing environmental quality. Objective: This study aims to examine significant factors affecting the Environmental Quality Index (EQI) across Indonesian provinces using appropriate nonparametric statistical methods. Methods: A nonparametric regression approach, specifically the Multivariate Adaptive Regression Spline (MARS) and the truncated spline multipredictor model, was applied. Predictor variables included the Human Development Index (HDI), population density, access to proper sanitation, poverty rate, and Gross Regional Domestic Product (GRDP). Secondary data for 34 provinces in 2022 were sourced from the Central Bureau of Statistics and the Ministry of Environment. Results: The truncated spline model demonstrated superior performance, achieving a minimal MSE of 5.63308, minimal GCV of 10.42, and R2  of 82.63%, outperforming MARS, which yielded a minimal MSE of 7.685, GCV of 16.014, and R2 of 79.3%. All predictor variables significantly influenced EQI. Conclusion: Social and economic factors were found to significantly affect environmental quality. The truncated spline approach offers an effective modeling alternative, providing critical insights to support environmental policy development at the provincial level.
Peran Minat Beli dalam Memediasi Rasa Percaya, Persepsian Harga dan Risiko terhadap Keputusan Pembelian Salsabila, Hanif; Suliyanto, Suliyanto; Gunistiyo, Gunistiyo; Setyowati, Ratna Faridah
Journal of Trends Economics and Accounting Research Vol 5 No 4 (2025): June 2025
Publisher : Forum Kerjasama Pendidikan Tinggi (FKPT)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.47065/jtear.v5i4.2104

Abstract

This study aims to analyze the influence of consumer trust, price perception, and risk perception on purchasing decisions with purchase intention as a mediating variable at PT. Bangun Anugrah Beton Nusantara (PT. BABN). Respondents in this study were consumers who had purchased products from PT. BABN. A total of 145 respondents were selected using convenience sampling techniques. Data were collected through questionnaires and analyzed using the Structural Equation Modeling (SEM) method with the help of Smart PLS 3.0 software. The results showed that consumer trust, price perception, and risk perception had a significant effect on purchase intention. However, only price perception and risk perception had a direct effect on purchasing decisions, while the direct effect of consumer trust was not significant. Purchase intention proved to be the strongest determinant in explaining purchasing decisions (32.5%) and effectively mediated the relationship between the three independent variables and purchasing decisions. This finding confirms that the company's marketing strategy should prioritize the formation of purchase intention to encourage consumer purchasing decisions.
Comparison of Vector Error Correction Model Prediction and Multiresponse Fourier Series, Case Study: Open Unemployment Rate in Indones IA Suliyanto, Suliyanto; Amelia, Dita; Raya, Kezya Bato; Evelyn, Jennifer
JTAM (Jurnal Teori dan Aplikasi Matematika) Vol 8, No 4 (2024): October
Publisher : Universitas Muhammadiyah Mataram

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.31764/jtam.v8i4.24108

Abstract

Unemployment is someone who has been classified in the active labour force is looking for work at a certain wage level, but not getting the job they want. According to the International Monetary Fund (IMF) 2023, Indonesia is ranked second highest in Southeast Asia, ranked 16th in Asia and ranked 58th in the world with a percentage of 5.45%. The data used in this study is semester data (February and August) regarding the number of open unemployment according to the highest education completed in Indonesia taken from the website of the Central Statistics Agency (BPS) starting from 2000 to 2022. This study using comparison of multi response Fourier series regression with trigonometry method using Gamma and the Vector Error Correction Model (VECM). The result of this study is Fourier series regression method of the cos function with gamma is the best model in predicting because this method has smaller MAPE value compared to VECM method. The MAPE of Fourier Series method is 0.01%, in other hand the MAPE of VECM method is 18.90% which can be categorized as prediction results with the Fourier Series method are very accurate. The results of prediction are expected to be used as reference for government to making ideal future plan to minimalize the rate of open unemployment in Indonesia. 
COMPARISON OF POISSON REGRESSION AND GENERALIZED POISSON REGRESSION IN MODELING THE NUMBER OF INFANT MORTALITY IN WEST JAVA 2022 Saifudin, Toha; Salsabila, Fatiha Nadia; Fitriani, Mubadi'ul; Kholidiyah, Azizatul; Auliyah, Nina; Ariani, Fildzah Tri Januar; Suliyanto, Suliyanto
BAREKENG: Jurnal Ilmu Matematika dan Terapan Vol 19 No 1 (2025): BAREKENG: Journal of Mathematics and Its Application
Publisher : PATTIMURA UNIVERSITY

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.30598/barekengvol19iss1pp35-50

Abstract

In line with the Sustainable Development Goals (SDGs), the Infant Mortality Rate (AKB) is a very important health indicator, especially in neonatal and perinatal care. West Java Province consistently ranks third nationally in terms of infant mortality in 2020 and 2021. This study analyzes the factors influencing infant mortality in West Java in 2022 using secondary data from the 2022 West Java Provincial Health Profile. The response variable is the number of infant deaths, while the predictor variables include the percentage of K-4 coverage (X1), high-risk pregnancy (X2), family with PHBS (X3), exclusive breastfeeding (X4), and complete immunization coverage (X5). Given the count-based nature of the data, Poisson regression was used, which assumes equidispersion where the variance is equal to the mean. However, the analysis found overdispersion, where the variance significantly exceeds the mean, making Poisson regression unsuitable. To address this, Generalized Poisson Regression (GPR) was applied, as GPR introduces a dispersion parameter that accounts for overdispersion, thus better fitting the data. The initial Poisson regression results showed that X1, X2, X4, and X5 significantly influenced infant mortality, while the GPR model showed that only X2 and X3 were significant factors, with a dispersion parameter of -3.116. The GPR model shows that every additional one high-risk pregnancy increases the infant mortality rate by 1.00006, while an increase of one unit of clean and healthy living practices reduces the mortality rate by 2.66%. Model evaluation using AIC, BIC, and RMSE confirmed that the GPR model better described the relationship between predictor variables and infant mortality rates compared to Poisson regression. These findings emphasize the need to use GPR to model cases with overdispersion in count data, so as to provide more reliable information for policy and intervention strategies.
MODELING DEMOCRACY INDEX IN INDONESIA WITH MULTIVARIATE ADAPTIVE REGRESSION SPLINE APPROACH Saifudin, Toha; Suliyanto, Suliyanto; Nugraha, Galuh Cahya; Valida, Hanny; Nahar, Muhammad Hafidzuddin; Fortunata, Regina
BAREKENG: Jurnal Ilmu Matematika dan Terapan Vol 19 No 4 (2025): BAREKENG: Journal of Mathematics and Its Application
Publisher : PATTIMURA UNIVERSITY

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.30598/barekengvol19iss4pp2347-2358

Abstract

Democracy is a system of government where citizens participate in political decision-making through freely elected representatives. To measure the quality of democracy in Indonesia, the Indonesian Democracy Index (IDI) is used as a composite indicator reflecting various aspects of political freedoms, civil liberties, and governance. The IDI score declined from 6.71 in 2022 to 6.53 in 2023, the lowest in 14 years, indicating disruption in Indonesia’s democracy. Therefore, it is necessary to identify the root causes of the disruption in Indonesia’s democracy through several indicators. This study analyzes the relationship between predictor variables, including socio-economic and development indicators, and IDI using the Multivariate Adaptive Regression Spline (MARS) approach. This study uses the MARS method by considering six predictor variables, namely the Human Development Index (HDI), Gender Empowerment Index (GEI), Information and Communication Technology Development Index (ICT-DI), Press Freedom Index (PFI), Poverty Depth Index (PDI), and High School Completion Rate (HSCR). The data used is secondary data from 34 Indonesian provinces in 2023 obtained from the Statistics Indonesia-BPS. The results showed that the best model was obtained with a combination of BF = 12, MI = 3, and MO = 1 resulting in a GCV value of 11.27 and R2 of 80%. MARS model interpretation identifies the significant influence of social and economic indicators on IDI and is able to explain 80% of data variability. The significance test shows that all predictor variables significantly affect the IDI, with the highest level of importance on the ICT-DI variable. Therefore, improving ICT-DI in each province needs to be a major concern as a strategic step to improve the democracy index in Indonesia and support the achievement of Sustainable Development Goal 16 on peace, justice, and strong institutions.
ANALYSIS OF GLOBAL ECONOMIC UNCERTAINTY IMPACT ON INDONESIA’S FINANCIAL AND TRADE VOLATILITY USING VECTOR ERROR CORRECTION MODEL WITH EXOGENOUS VARIABLES Amelia, Dita; Suliyanto, Suliyanto; Nugraha, Galuh Cahya; Suyono, Billy Christandy
BAREKENG: Jurnal Ilmu Matematika dan Terapan Vol 19 No 4 (2025): BAREKENG: Journal of Mathematics and Its Application
Publisher : PATTIMURA UNIVERSITY

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.30598/barekengvol19iss4pp2963-2980

Abstract

Increasing global economic uncertainty due to the influence of geopolitical dynamics and monetary policy adjustments from major countries has significantly impacted financial and trade stability in Indonesia. This research examines the relationship between global economic uncertainty and the volatility of Indonesia's financial and trade indicators using the Vector Error Correction Model with Exogenous Variables (VECM-X) approach. The model incorporates external factors such as the US Dollar Index (DXY), Volatility Index (VIX), and Trade Policy Uncertainty (TPU), using monthly data from January 2019 to December 2024. The results of the analysis show that each variable has different volatility with patterns that tend to fluctuate, and there is a cointegration relationship between the variables of the Rupiah exchange rate (USD/IDR), Jakarta Composite Index (JCI), interest rates, export, and imports. The causality test results show that exports, JCI, and imports affect interest rates without a reverse relationship, while there is a one-way relationship between exports and imports and JCI and the exchange rate. In addition, imports and JCI have a two-way relationship that affects each other. Impulse Response Function (IRF) results indicate dynamic short-term interactions among endogenous variables, which gradually stabilize over the medium to long term. In addition, the variance decomposition results show that most of the variability of each variable is explained by itself in the short term, with contributions from other variables increasing over time. This research contributes to Sustainable Development Goals (SDGs) point 8: Decent Work and Economic Growth, by providing insight to strengthen Indonesia's macroeconomic resilience. Integrating exogenous global indicators into the VECM-X model offers a more comprehensive understanding of how global shocks affect domestic stability. However, this study is limited to a macro-level analysis using secondary data and does not account for microeconomic or sectoral variations.
Exploring the Factors Influencing Consumer Reconsumption Intention of Herbal Medicine Ahmed Bakhit, Mohammed Elfadil; Sudarto, Sudarto; Najmudin, Najmudin; Suliyanto, Suliyanto; Weni, Weni
The Es Economics and Entrepreneurship Vol. 4 No. 01 (2025): The Es Economics And Entrepreneurship (ESEE)
Publisher : Eastasouth Institute

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.58812/esee.v4i01.623

Abstract

The research explores the factors of consumers’ trust in herbal medicine, perceived value, and the reconsumption intention that influence Indonesians to use herbal medicine for treatment and protection health conditions. This research uses consumer perceived value and relationship quality theory to explain research phenomena. The regression model was It employed a quantitative approach to determine the relationship of between consumers consumption behavior and herbal products. The sample in this study was selected using a purposive sampling. collected data by questionnaire. The results All proposed hypotheses are accepted, such as the effect of trust and perceived value on reconsumption intention. These results showed that consumer trust in the value and benefits of herbal medicine mediate the effect of perceived value on reconsumption intention. Therefore, there are still other factors included in this study related to consumers’ intention to (re)consume herbal medicine.
Pengaruh Suplementasi Vitamin D dan BMI terhadap LVEF dengan Pendekatan Generalized Additive Models Longitudinal Amelia, Dita; Suliyanto, Suliyanto; Alexandra, Victoria Anggia; Yosifa, Adelia Frielady; Rakhma , Syavrilia Alfiatur; Julianto, Agnes Happy
Limits: Journal of Mathematics and Its Applications Vol. 22 No. 1 (2025): Limits: Journal of Mathematics and Its Applications Volume 22 Nomor 1 Edisi Ma
Publisher : Pusat Publikasi Ilmiah LPPM Institut Teknologi Sepuluh Nopember

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12962/limits.v22i1.3378

Abstract

Cardiovascular diseases (CVD) are the leading cause of global mortality, with Left Ventricular Ejection Fraction (LVEF) being a key indicator of heart function. This study explores the impact of vitamin D supplementation and Body Mass Index (BMI) on LVEF using Generalized Additive Models (GAM) in longitudinal data from 47 elderly patients with hypovitaminosis D undergoing orthopedic surgery. LVEF was measured before surgery and at 1, 3, and 6 months post-intervention. GAM was employed to capture nonlinear relationships between variables with working correlation structures such as Independence, Exchangeable, Unstructured, and Autoregressive-1 (AR-1). The findings revealed a significant increase in vitamin D levels and LVEF following supplementation, while BMI remained relatively stable throughout the observation period. The best GAM model with AR-1 correlation structure achieved the lowest Quasi Information Criterion (QIC) score of 443.47, indicating a complex relationship between vitamin D and LVEF and a linear relationship between BMI and LVEF. Vitamin D demonstrated a significant nonlinear effect on LVEF improvement, whereas a 1-point increase in BMI raised LVEF by 0.291%. This study underscores the importance of vitamin D supplementation in enhancing heart function among elderly patients with hypovitaminosis D, supporting the development of evidence-based health policies
Co-Authors Aflaha, Nabila Shafa Ahmed Bakhit, Mohammed Elfadil Alexandra, Victoria Anggia Aliffia, Netha Alisa Tri Nawarini, Alisa Tri Ariani, Fildzah Tri Januar Arini, Destia Vindha Aris Kurniawan Aris Susetyo Ariyawan, Jovansha Arofah, Triani ary yunanto Astuti, Nurul Istiqomah Tri Aulia, Niswa Faizah Auliyah, Nina Bambang Agus Pramuka Christiano Ginzel, Bryan Given Dewanty, Sanda Insania Dewi Susilowati Dewi, Cyntia Dita Amelia Dita Amelia, Dita Eliada Herwiyanti Elly Ana Evelyn, Jennifer Fadliyana Ekawaty Fitri, Marfa Audilla Fitriani, Mubadi'ul Fortunata, Regina Gunistiyo, Gunistiyo Indradewa, Rhian Indyastuti, Nurhayati Irawan, Andry Julianto, Agnes Happy Kholidiyah, Azizatul Koesnadi, Grace Lucyana M. Fariz Fadillah Mardianto Mahfudhotin, Mahfudhotin MANDIRA, DARA AJENG Nahar, Muhammad Hafidzuddin Najmudin Naura, Sheila Sevira Asteriska Nendyah Roestijawati Nugraha, Galuh Cahya Nurdin, Nabila OKTARIA, RINA RINA Oktavia, Sabrina Salsa Parno Parno Prabaningrum, Meliyana Rizki Pradipta, Refius Pratama, Bagas Shata PUJI LESTARI Rachmatiko, Rofi Rahab Rahab, Rahab Rahmajati, Emir Surya Rakhma , Syavrilia Alfiatur Raya, Kezya Bato Riska Amalya Nasution Rohiwan, Sidik Salsabila, Fatiha Nadia Salsabila, Hanif Sediono, Sediono Setyowati, Ratna Faridah Shabariyatun, Tri Aprilisa Siti Zulaikha Sudarto Sudarto Sulasih Sulasih Suryati Suryati Suyono, Billy Christandy Tjahjono, Eko Toha Saifudin Ubadah, Mohammad Noufal Valida, Hanny Wahyuningtyas, Ida Puspitarini Weni Novandari Weni, Weni Wulandari, Indana Zulfa Yosifa, Adelia Frielady Yuwono, Antri