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Assessing Solar Energy Potential through Sunshine Hour Interpolation using Spatiotemporal Kriging with Local Drift Nugroho, Salma Fitri; Fitriani, Rahma; Iriany, Atiek
JTAM (Jurnal Teori dan Aplikasi Matematika) Vol 9, No 4 (2025): October
Publisher : Universitas Muhammadiyah Mataram

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.31764/jtam.v9i4.32048

Abstract

Solar energy is a key renewable resource, particularly valuable in tropical regions like Bali, where sunlight is consistently available throughout the year. Accurate estimation of sunshine duration is essential for assessing solar energy potential, as it directly affects photovoltaic (PV) system performace and informs strategic planning for renewable energy development. This study aims to develop a spatiotemporal statistical interpolation model to estimate and predict sunshine duration patterns across Bali, thereby enhancing the planning and deployment of solar energy infrastructure. This quantitative research applies space-time kriging with local drift using sunshine duration data (in hours) collected from four meteorological stations between 2019 and 2023. The method effectively captures spatial and temporal dependencies by integrating local drift as a deterministic trend component. Among several models tested, the Gaussian-Gaussian-Gaussian (Gau-Gau-Gau) combination delivered the best performance, with an RMSE of 2.3085. The results show a clear seasonal cycle, with higher sunshine duration during the dry season (May–October) and lower values in the wet season (November–March). Northern and eastern Bali, particularly Buleleng and Karangasem, demonstrate the highest solar potential, while central mountainous areas show lower sunshine exposure due to cloud coverage. These results offer not only a methodological contribution through the application of spatiotemporal kriging with local drift, but also a practical framework for decision-makers. The insights can guide strategic placement of solar farms, optimize energy yield forecasts, and support resilient infrastructure planning in line with Bali’s climatic realities and energy needs.
The Application of Truncated Spline Semiparametric Path Analysis on Determining Factors Influencing Cashless Society Development Pramaningrum, Dea Saraswati; Fernandes, Adji Achmad Rinaldo; Iriany, Atiek; Solimun, Solimun
JTAM (Jurnal Teori dan Aplikasi Matematika) Vol 8, No 2 (2024): April
Publisher : Universitas Muhammadiyah Mataram

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.31764/jtam.v8i2.19913

Abstract

Semiparametric path analysis is a combination of parametric and nonparametric path analysis. Semiparametric path analysis is used when there are partially nonlinear and unknown patterns of relationships. One approach to semiparametric pathways is truncated spline. Truncated spline approach tends to search for their own estimation of regression functions according to the data. This is because in the truncated spline there are knot points, which are intersection points that indicate changes in data behavior patterns. Truncated spline semiparametric path analysis will be applied to this study to determine the variables that have a significant effect on the development of the Cashless Society so that the result can be used as a reference for banks and the government in maximizing non-cash-based community development. The data used is the result of a questionnaire with 100 respondents of mobile banking users in Jakarta and will be analyzed using R Studio. Based on the results, it was found that the optimal knot point in the truncated spline function is 3 with many knots is 1, thus dividing the condition of digitizing electronic money into 2 regimes. It was concluded that the product and digitalization of electronic money had a significant effect on the development of cashless society where the modeling obtained could explain 83.87548% of the data. However, when electronic digitalization increases through the value of knot points, the development of cashless society tends to stagnate. This could be due to people who are not ready when the condition of digitizing electronic money is increasingly sophisticated because the available electronic money features are increasingly complex. Therefore, it is important for banks to pay attention to the sophistication of electronic money features provided to customers and adjust the target market so that customers are more accustomed and comfortable to use electronic money in the future.
Comparison of Mediation Effects on Interaction and Multigroup Approach in Structural Equation Modeling PLS in Case of Bank Mortgage Maisaroh, Ulfah; Fernandes, Adji Achmad Rinaldo; Iriany, Atiek; Ullah, Mohammad Ohid
JTAM (Jurnal Teori dan Aplikasi Matematika) Vol 8, No 1 (2024): January
Publisher : Universitas Muhammadiyah Mataram

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.31764/jtam.v8i1.19919

Abstract

“Structural Equation Modeling is one of multivariate statistical method that used to explain multiple relationships between latent variables simultaneously to test a mediation model to conduct a formal test on mediation effects. Application PLS-SEM for exploratory research and theory development are increasing. Under certain conditions, the effect of exogenous variables on endogenous variable is also strengthened or weakened by moderating variable. In SEM, there are two approaches in analyzing moderation variables, namely the interaction method and the multigroup method. This article aims to compare the mediation effect on interaction approaches and multigroup approaches in Structural Equation Modeling. The data used is the case of timeliness of Bank X mortgage payments. In this article, statistical methods are evaluated to compare indirect effect between groups and examine indirect effect on each group. It was concluded that Collectability Status moderates the indirect relationship between Capital and the Timeliness of Payment through Willingness to Pay. Debtors with current collectability status more strongly effect the Timeliness of Payment than debtors with incurrect collectability status. Theresults of testing indirect effects on moderation with interaction and multigroup approaches are not much different. In the multigroup approach, the bootstrap interval bias is smaller than the bootstrap interval bias in the interaction approach. The Q-square Predictive Relevance value in both methods is quite high, indicating that the model is good. On the Current Collectibility Status group Q^2 is 89.3%, in the incurrect Collectibility Status Q^2 is 84.2%. While in the interaction approach, Q^2 is 70.4%. Researcher recommend a multigroup approach to data that has categorical moderation variables because differences between groups can be directly observed without adding interaction variables in the model.”
PENDAMPINGAN PENATAAN SISTEM ADMINISTRASI DESA DENGAN MENGEMBANGKAN APLIKASI ADMINISTRASI DESA TERPADU DI KELURAHAN ARJOSARI Pramoedyo, Henny; Ngabu, Wigbertus; Wardhani, Ni Wayan Surya; Iriany, Atiek; Chairunissa, Abela
PAKEM : Jurnal Pengabdian Kepada Masyarakat Vol 5 No 2 (2025): Pakem : Jurnal Pengabdian Kepada Masyarakat
Publisher : Universitas Pattimura

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.30598/pakem.5.2.131-142

Abstract

This community service activity aims to assist Kelurahan Arjosari in restructuring its administrative system more effectively and efficiently through the development of a village administration application built with Microsoft Excel and Visual Basic for Applications (VBA). Based on initial observations, the administrative processes in the kelurahan were still conducted manually, leading to slow public service delivery and a high risk of errors. The developed application is designed to integrate with the village's population database, automate the generation of documents based on National Identification Numbers (NIK), and provide automatic data validation features. Through Focus Group Discussions (FGD) and the official launching of the application, local officials were actively involved in the planning and training phases. Evaluation results show that the application is easy to use, accelerates the document service process, and improves administrative data accuracy. This initiative has had a positive impact on the quality of public services at the local level and serves as a model for applying simple but effective technology to support digital transformation in village governance
Introduksi Budidaya Komoditas Jagung Hibrida dan Kacang Hijau di Kabupaten Malaka Sugiharto, Arifin Noor; Iriany, Atiek; Ngabu, Wigbertus; Ridwan, Muhamad; Anam, Khoiril
ABDI UNISAP: Jurnal Pengabdian Kepada Masyarakat Vol. 1 No. 2 (2023): ABDI UNISAP: Jurnal Pengabdian Kepada Masyarakat
Publisher : UPT Publikasi dan Penerbitan Universitas San Pedro

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.59632/abdiunisap.v1i2.202

Abstract

Praktik budi daya tanaman kacang hijau dan jagung yang dilakukan oleh petani di kawasan transmigrasi Uluklubuk masih belum optimal. Belum optimalnya praktik budi daya ini disebabkan karena penggunaan varietas lokal yang produktivitasnya rendah serta rendahnya penggunaan pupuk untuk mendukung pertumbuhan tanaman. Untuk mengatasi permasalahan mitra kelompok tani, maka beberapa solusi yang diberikan adalah transfer teknologi melalui pendampingan, pelatihan, dan praktik demplot. Pelaksanaan program ini dilaksanakan dengan metode pelatihan, penyuluhan, pendampingan, dan demplot secara berkala. Program kegiatan ini bertujuan untuk mengenalkan varietas jagung hibrida, varietas kacang hijau unggul, dan transfer teknologi budi daya tanaman jagung dan kacang hijau serta meningkatkan pendapatan kelompok tani di Desa Weoe, Kecamatan Wewiku, Kabupaten Malaka. Kegiatan pengabdian dilaksanakan pada bulan Juni sampai dengan Desember 2023. Hasil program kegiatan pengabdian ini menunjukkan bahwa kelompok tani sasaran mampu mengimplementasikan ilmu pengetahuan yang telah diberikan mengenai budi daya jagung hibrida dan kacang hijau unggul. Hasil panen jagung yang diperoleh adalah sebesar 12,877 ton dan hasil panen kacang hijau sebanyak 1,481 ton.
PENAMBAHAN METODE NEURAL NETWORK DALAM PEMODELAN GSTAR-SUR UNTUK MENGATASI KASUS NON LINIER PADA PERAMALAN DATA CURAH HUJAN Iriany, Atiek; Fernandes, Adji Achmad Rinaldo; Efendi, Achmad; Putri, Henida Ratna Ayu; Ariyanto, Danang; Ngabu, Wigbertus
MATHunesa: Jurnal Ilmiah Matematika Vol. 12 No. 1 (2024)
Publisher : Universitas Negeri Surabaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.26740/mathunesa.v12n1.p226-236

Abstract

Salah satu model peramalan yang dapat yang menggabungkan unsur spasial (spatial) dan temporal (time) adalah Generalized Space Time Autoregressive (GSTAR). Pendugaan parameter yang digunakan adalah Seemingly Unrelated Regression (SUR). Peramalan iklim pada tanaman hortikultura pada masa kini sulit untuk diprediksi karena memiliki pola dan karakteristik yang sulit diidentifikasi dan dapat disebut aktivitas non linier. Unsur non linier ini dapat ditangkap oleh metode neural network. Penelitian ini ingin mengetahui hasil peramalan curah hujan pada 6 wilayah di Tengger menggunakan model GSTAR dengan pendugaan parameter menggunakan metode SUR dan digabungkan dengan neural network agar hasil peramalan yang lebih akurat. Data yang digunakan dalam penelitian ini adalah data curah hujan enam lokasi di wilayah Tengger, yakni Ngadirejo, Puspo, Wonokitri, Argosari, Ngadas, dan Wonokerto. Model yang tepat dalam melakukan peramalan pada data curah hujan pada 6 lokasi Tengger adalah model GSTAR (1,2,3,4,5,6,7,36(1)) Backpropagation Neural Network (96-120-6).
ANALISIS FAKTOR YANG MEMENGARUHI PRODUKTIVITAS JAGUNG DI DESA ANAENGGE KECAMATAN KODI KABUPATEN SUMBA BARAT DAYA Ngabu, Wigbertus; Iriany, Atiek
Agros Journal of Agriculture Science Vol 25, No 1 (2023): edisi JANUARI
Publisher : Fakultas Pertanian, Universitas Janabadra

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.37159/jpa.v25i1.2471

Abstract

Komoditas jagung merupakan bahan makanan utama kedua setelah beras. Selain itu, jagung juga digunakan sebagai bahan pakan ternak dan bahan baku industri. Jika pemenuhan bahan pakan terganggu, maka pada akhirnya akan mengganggu pemenuhan kebutuhan protein dan peningkatan gizi bagi masyarakat. Oleh karena itu, jagung dipandang sebagai komoditas yang cukup strategis seperti halnya beras. Jagung merupakan salah satu sumber karbohidrat yang cukup potensial terutama di Indonesia Timur. Selain sebagai sumber bahan pangan, jagung juga menjanjikan banyak harapan untuk dijadikan sebagai bahan baku berbagai macam keperluan industri. Salah satu daerah potensial untuk produksi jagung adalah Kabupaten Sumba Barat daya yang memiliki banyak lahan marjinal (lahan kering). Penelitian ini bertujuan untuk mengetahui faktor-faktor yang memengaruhi produktivitas Jagung di Kabupaten Sumba Barat Daya dengan benih unggul Brawijaya Nusa 01. Metode yang digunakan yaitu regresi linear berganda, dan diproleh hasil variabel yang signifikan berpengaruh terhadap produktivitas jagung di desa Anaengge Kabupaten Sumba Barat Daya Luas Lahan, Benih, NPK, Urea, Pestisida. Diproleh hasil R2 sebesar 93.26%, hasil ini menujukan variabel produktivitas jagung
Structural Equation Modeling Semiparametric Truncated Spline in Banking Credit Risk Behavior Models Amanda, Devi Veda; Iriany, Atiek; Fernandes, Adji Achmad Rinaldo; Solimun, Solimun
CAUCHY: Jurnal Matematika Murni dan Aplikasi Vol 10, No 1 (2025): CAUCHY: JURNAL MATEMATIKA MURNI DAN APLIKASI
Publisher : Mathematics Department, Universitas Islam Negeri Maulana Malik Ibrahim Malang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.18860/cauchy.v10i1.29769

Abstract

Housing is one of the primary needs for every individual. Along with the increasing population growth in Indonesia, the need for housing has also experienced a significant surge. This study aims to analyze the effect of customer attitudes on compliance behavior, fear of paying late, and timeliness of payment on Home Ownership Credit (KPR) customers at X Bank. Using a semiparametric Structural Equation Modeling (SEM) approach, this study examines the relationship between these variables to provide a deeper understanding of the factors that influence customer payment behavior. The data used in this study are primary data obtained through questionnaires distributed to 100 Bank X mortgage customers. The results of the analysis show that there is a significant influence between customer attitudes (X1) on obedient payment behavior (Y1) and fear of paying late (Y2), as well as timeliness of payment (Y3). The estimated coefficients obtained show a positive relationship between compliance behavior and timeliness of payment, and a negative relationship between fear of paying late and timeliness of payment, with a p-value 0.001 indicating statistical significance. This finding indicates that good customer attitudes can improve payment timeliness, while poor attitudes can lead to fear of paying late, which in turn can affect payment timeliness.
Ensemble Cluster Method For Clustering Cabbage Production In East Java Maghfiro, Maulidya; Wardhani, Ni Wayan Surya; Iriany, Atiek
Inferensi Vol 7, No 2 (2024)
Publisher : Department of Statistics ITS

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12962/j27213862.v7i2.20378

Abstract

Cluster analysis is a multivariate analysis method classified under interdependence methods, where explanatory variables are not differentiated from response variables. The methods used include hierarchical cluster analysis, such as agglomerative and divisive, and non-hierarchical methods such as Self Organizing Maps (SOM) based on Artificial Neural Networks (ANN). Various cluster analysis methods often yield diverse solutions, making it challenging to determine the optimal solution. Therefore, the ensemble cluster method is employed to combine various clustering solutions without considering the initial data characteristics with providing better results. One case study of clustering is the grouping of cabbage production. East Java Province has become the third-highest cabbage-producing province in Indonesia with a production of 210,454 tons. Clustering of cabbage-producing regencies/cities was conducted to optimize production and identify areas that have not yet reached their maximum potential. This study compares five clustering methods which are hierarchical analysis (complete linkage, single linkage, average linkage), Self-Organizing Map (SOM), and Ensemble Cluster. The quality of clustering was evaluated using the Silhouette Coefficient (SC), Dunn Index (DI), and Connectivity Index (CI). The results indicate that the Ensemble Cluster method showed the best performance, with an SC value of 0.9124, a DI value of 1.3734, and a CI value of 2.9290, indicating excellent cluster separation. Therefore, the ensemble cluster method is recommended as the best clustering method in this study.
Nonparametric Path Modeling with Double Resampling for Waste Economic Value Utilization: Simulation-Based Performance Comparison Hidayat, Kamelia; Fernandes, Adji Achmad Rinaldo; Iriany, Atiek; Solimun, Solimun; Hidayatulloh, Moh. Zhafran; Junianto, Fachira Haneinanda
CAUCHY: Jurnal Matematika Murni dan Aplikasi Vol 10, No 2 (2025): CAUCHY: JURNAL MATEMATIKA MURNI DAN APLIKASI
Publisher : Mathematics Department, Universitas Islam Negeri Maulana Malik Ibrahim Malang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.18860/cauchy.v10i2.37218

Abstract

Waste generation exceeding landfill capacity highlights the urgency of realizing its economic value. This study analyzes the effect of Quality of Facilities and Infrastructure (X1) and Use of Waste Banks (X2) on Waste Management-Based 3R (Y1) and Waste Economic Value Utilization (Y2) using a truncated spline nonparametric path model. This study evaluates the performance of a nonparametric path analysis model based on truncated spline combined with a double resampling. Data were collected using a Likert scale questionnaire on community perceptions of waste’s economic benefits in Batu City. Simulation results show that the Jackknife-Bootstrap method achieves the lowest average bias (0.058), outperforming single resampling approaches such as Single-Bootstrap (0.178) and Single-Jackknife (0.176). Empirical findings indicate that improvements in the Quality of Facilities and Infrastructure  (X1) and Waste Bank Use (X2) significantly enhance Waste Management Based 3R (Y1) and Utilization of Waste Economic Value (Y2). The truncated spline model reveals a saturation effect, where the marginal benefits of X1 and X2 decrease beyond a threshold. Furthermore, Y1 positively affects Y2, emphasizing the importance of efficient waste management in enhancing economic value. The results support policies promoting balanced infrastructure development, community empowerment, and institutional innovation for sustainable circular economy implementation.
Co-Authors A. Fahmi Indrayani Achmad Efendi Agus Dwi Sulistyono, Agus Dwi Alim, Viky Iqbal Azizul Amanda, Devi Veda Aniek Iriany Arditama Putra Rochmanullah Arianto, Danang Arifin Noor Sugiharto Aris Subagiyo Asaliontin, Lisa Ayu Aisyah Ashari Bambang Dwi Argo Bestari Archita Safitri Budi Astuti, Ani Cecep Kusmana Chairunissa, Abela Danang Ariyanto Darmanto Darmanto David Forgenie Dewi, Anggi Seftia Dhanny Septimawan Sutopo Eni Sumarminingsih Faddli Lindra Wibowo Fernandes, Adji Fernandes, Adji Achmad Rinaldo Firdaus, Cahyani Jannah Fudianita, Citra Hamdan, Rosita Haneinanda Junianto, Fachira Hartawati, Hartawati Henny Pramoedyo Henny Pramoedyo Hidayat, Kamelia Hidayatulloh, Moh. Zhafran Iwan Setiawan Junianto, Fachira Haneinanda Khoiril Anam, Khoiril Kusdarwati, Heni Maghfiro, Maulidya Maghfiro, Maulidya Maisaroh, Ulfah Marhen Andan Prasetyo Mellysa Isnaini Muhamad Firdaus Muhamad Ridwan NI WAYAN SURYA WARDHANI Ni Wayan Surya Wardhani Nikmatul Khoiriyah Novi Nur Aini Novi Nur Aini, Novi Nur Nugroho, Arief Budi Nugroho, Salma Fitri Ola, Petrus Kanisius Pramaningrum, Dea Saraswati Putra, Arditama Putri, Henida Ratna Ayu Rahma Fitriani Rinaldo Fernandes, Adji Achmad Riza, Sativandi Rosyida, Diana Rudiat Sekarsari, Cindy Sepriadi, Hanifa Solimun Solimun Solimun Solimun, Solimun Suci Astutik Sugiarto S Suryawardhani, Ni Wayan Sutopo, Dhanny Septimawan Ullah, Mohammad Ohid Utomo, Candra Rezzining Wulat Sariro Weni Waego Hadi Nugroho Wardhani, Ni Wayan Surya Wigbertus Ngabu Yuliana, Mila