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All Journal CAUCHY: Jurnal Matematika Murni dan Aplikasi AdMathEdu : Jurnal Ilmiah Pendidikan Matematika, Ilmu Matematika dan Matematika Terapan Kubik Jurnal Sains Matematika dan Statistika Edumatsains NUMERICAL (Jurnal Matematika dan Pendidikan Matematika) Sinkron : Jurnal dan Penelitian Teknik Informatika Desimal: Jurnal Matematika BAREKENG: Jurnal Ilmu Matematika dan Terapan Justek : Jurnal Sains Dan Teknologi JURNAL TEKNIK INFORMATIKA DAN SISTEM INFORMASI Zeta - Math Journal Jurnal Pendidikan Matematika (JUDIKA EDUCATION) NUSANTARA : Jurnal Ilmu Pengetahuan Sosial Zero : Jurnal Sains, Matematika, dan Terapan JISTech (Journal of Islamic Science and Technology) AXIOM : Jurnal Pendidikan dan Matematika JURNAL MathEdu (Mathematic Education Journal) JOURNAL OF SCIENCE AND SOCIAL RESEARCH Saintifik : Jurnal Matematika, Sains, dan Pembelajarannya M A T H L I N E : Jurnal Matematika dan Pendidikan Matematika Math Educa Journal Progresif: Jurnal Ilmiah Komputer JURNAL PEMBELAJARAN DAN MATEMATIKA SIGMA (JPMS) Proximal: Jurnal Penelitian Matematika dan Pendidikan Matematika JOURNAL OF INFORMATION SYSTEM RESEARCH (JOSH) SEPREN: Journal of Mathematics Education and Applied Community Development Journal: Jurnal Pengabdian Masyarakat Theta : Jurnal Pendidikan Matematika Jurnal Lebesgue : Jurnal Ilmiah Pendidikan Matematika, Matematika dan Statistika Jurnal Pengabdian kepada Masyarakat Nusantara KUBIK: Jurnal Publikasi Ilmiah Matematika FARABI: Jurnal Matematika dan Pendidikan Matematika Algebra : Jurnal Pendidikan, Sosial, dan Sains Mathematics and Applications (MAp) Journal Humantech : Jurnal Ilmiah Multidisiplin Indonesia Jurnal IPTEK Bagi Masyarakat Journal of Mathematics and Scientific Computing With Applications Relevan Jurnal Informatika Teknologi dan Sains (Jinteks) Edu Society: Jurnal Pendidikan, Ilmu Sosial dan Pengabdian Kepada Masyarakat Prisma Sains: Jurnal Pengkajian Ilmu dan Pembelajaran Matematika dan IPA IKIP Mataram Abdimas Indonesian Journal Bulletin of Applied Mathematics and Mathematics Education International Conference on Sciences Development and Technology JS (Jurnal Sekolah) Jurnal Bayesian : Jurnal Ilmiah Statistika dan Ekonometrika JME APPA : Jurnal Pengabdian Kepada Masyarakat Faedah: Jurnal Hasil Kegiatan Pengabdian Masyarakat Indonesia Jurnal Pengabdian Masyarakat Algebra Indonesia Bergerak: Jurnal Hasil Kegiatan Pengabdian Masyarakat Relevan : Jurnal Pendidikan Matematika
Riri Syafitri Lubis
Universitas Islam Negeri Sumatera Utara, Medan, Indonesia
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Klasifikasi Kabupaten/ Kota Sejahtera dan Tidak Sejahtera dengan Metode Spectral Clustering pada Provinsi Sumatera Utara Batu, Annisa Rajaq Lumban; Lubis, Riri Syafitri; Harleni, Silvia
Proximal: Jurnal Penelitian Matematika dan Pendidikan Matematika Vol. 8 No. 1 (2025): Integrasi Matematika, Teknologi, dan Budaya dalam Pendidikan dan Aplikasi Terap
Publisher : Universitas Cokroaminoto Palopo

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.30605/proximal.v8i1.4887

Abstract

People's welfare is basically a condition whose form is dynamic or in other words its quantitative value will never stop because it will continue to change along with the development of human life needs. In the Regional Medium Term Development Plan (RPJMD) of North Sumatra Province, the government is trying to realize an advanced and prosperous community life. Law No. 11 of 2019 article 3 paragraph 1, it is also written that the purpose of administering social welfare is to increase the level of welfare, quality and survival. As according to the Central Statistics Agency for North Sumatra in 2021 regarding indicators of people's welfare, namely, population, health, education, employment, household consumption and expenditure, housing and the environment, and participation in social activities. To make a strategy to improve the welfare of the people of North Sumatra, the Government needs to determine which districts or cities are prosperous and which are not. This study uses the spectral clustering method in which this method forms clusters obtained according to data taken at the Central Bureau of Statistics which will be carried out in 2022 data taken in 2021. The results of this study indicate the application of the spectral clustering method for classifying prosperous and less prosperous city districts in North Sumatra province and clusters obtained as many as 2 clusters from data from 33 urban districts in North Sumatra province, namely cluster 1 is a prosperous district or city, namely Medan and Deli Serdang, and cluster 2 is a district or city that is not prosperous, namely, apart from Medan and Deli Serdang.
Penerapan Metode Regresi Probit Biner dalam Menganalisis Faktor-Faktor yang Berpengaruh pada Tingkat Partisipasi Angkatan Kerja Wanita Utami, Ristika Dian; Lubis, Riri Syafitri; Cipta, Hendra
Justek : Jurnal Sains dan Teknologi Vol 8, No 2 (2025): Juni
Publisher : Unversitas Muhammadiyah Mataram

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.31764/justek.v8i2.29162

Abstract

Abstract:  The female labor force participation rate (LFPR) describes the percentage of the female population of working age who are engaged in economic activities. In this condition, the problem that often arises is that the LFPR of women is still lower than the LFPR of men, and the gap between the two is quite far. The purpose of this study is to find out what factors affect the LFPR of women in North Sumatra Province. The method used is binary probit regression method. The data revealed that 45.5% of districts/cities in North Sumatra Province were classified as low LFPR category. The results showed that the level of education (X1) and the informal sector (X5) had a significant effect on female TPAK with a classification accuracy value of 93.9%, indicating that the binary probit regression model used was able to classify the data correctly with a high level of accuracy.Abstrak: Tingkat partisipasi angkatan kerja (TPAK) wanita menggambarkan persentase populasi wanita pada usia kerja yang terlibat dalam kegiatan ekonomi. Dalam kondisi ini, masalah yang sering muncul adalah TPAK wanita masih lebih rendah dari TPAK laki-laki, dan kesenjangan antara keduanya cukup jauh. Tujuan dari penelitian ini yaitu  untuk mengetahui faktor-faktor apa saja yang berpengaruh terhadap TPAK wanita di Provinsi Sumatera Utara. Metode yang digunakan adalah metode regresi probit biner. Data mengungkapkan bahwa 45,5% kabupaten/kota di Provinsi Sumatera Utara tergolong dalam kategori TPAK rendah. Hasil penelitian menunjukkan tingkat pendidikan (X1) dan sektor informal (X5) berpengaruh signifikan terhadap TPAK wanita dengan nilai ketepatan klasifikasi sebesar 93,9% menandakan model regresi probit biner yang digunakan mampu mengklasifikasikan data dengan tepat memiliki tingkat akurasi yang tinggi.
Application of k-prototypes algorithm to smoking addiction at FST UINSU medan Ritonga, Nurhalimah; Lubis, Riri Syafitri
Desimal: Jurnal Matematika Vol. 7 No. 3 (2024): Desimal: Jurnal Matematika
Publisher : Universitas Islam Negeri Raden Intan Lampung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24042/djm.v7i3.24374

Abstract

One of the addictive chemicals that can cause addiction is cigarettes. By combining smoking data among students of the Faculty of Science and Technology (FST) at UINSU Medan, this study seeks to overcome the problem of smoking. The K-Prototypes approach is one of the ones that is applied. Microsoft Excel 2010 and IBM SPSS Statistics are programs used to analyze research data. A sample questionnaire of FST students from UINSU Medan provided data. The findings showed that the K prototype had an impact on smoking factors, study programs, types of cigarettes, the number of cigarettes smoked, and the early age of smoking. There are 19 objects in Cluster 1, 21 objects in Cluster 2, and 25 objects in Cluster 3 students in each cluster. According to the cluster data of the K-Prototypes method, the smoking factor was caused by friends in cluster 1, which included early-age smokers (12.789) with 1.895 packs of salt warehouse cigarettes. In the second group of early smoking age groups (15.810), 1.381 packs of salt warehouse cigarettes were smoked, and the smoking factor was associated with the family. In the third group of early-age smokers (20.44), there were 1.96 packs of Marlboro cigarettes, and friends were a factor in smoking. Thus, the three study programs at FST UINSU Medan require a lot of attention from schools, families, and students.
Optimizing portfolio performance in indonesian banking stocks: An empirical application of the markowitz mean-variance framework Pulungan, Ahmad Fauzan; Riri Syafitri Lubis
Desimal: Jurnal Matematika Vol. 8 No. 2 (2025): Desimal: Jurnal Matematika
Publisher : Universitas Islam Negeri Raden Intan Lampung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24042/nxebn152

Abstract

This study aims to construct an optimal investment portfolio in Indonesia’s banking sector using the Mean-Variance Markowitz approach. Employing a quantitative descriptive method, the research analyzes monthly closing stock prices of 10 banking companies listed on the Indonesia Stock Exchange from January to December 2024. Data processing was conducted using Microsoft Excel, including return calculation, risk measurement through standard deviation, covariance matrix formation, and portfolio optimization via the Sharpe Ratio. The findings reveal that the optimal portfolio consists of BRIS and PNBN stocks, achieving the highest Sharpe Ratio of 0.6639, which reflects a well-balanced risk-return profile. Conversely, the minimum-risk portfolio yielded a negative return, highlighting that lower risk does not always translate to profit. These results affirm the effectiveness of the Markowitz model in supporting rational investment decision-making, particularly for young investors.
DYNAMICS OF RAINFALL AND TEMPERATURE IN NORTH SUMATRA PROVINCE: COMPREHENSIVE ANALYSIS OF TEMPORAL TRENDS Lubis, Riri Syafitri; Suzana, Yenny; Syarah, Fatmah; Fajriana, Fajriana; Rozi, Fachrur; Nusantara, Badai Charamsar
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/barekengvol19iss1pp215-226

Abstract

This research aims to analyze the temporal trends of rainfall and temperature in North Sumatra Province, focusing on the Medan and Deli Serdang regions. The data used in this study was obtained from the Central Statistics Agency of North Sumatra (BPS Sumut) and spans the period from January 2000 to December 2022. The Mann-Kendall test was applied to identify trends, Sen's Slope Estimator measured the trend slope, and Pearson correlation analysis assessed the relationship between rainfall and temperature. Key findings indicate that Medan has a higher monthly rainfall average than Deli Serdang, with both regions showing a significant increasing trend in rainfall, although the rise is gradual. Additionally, a positive trend in temperature was identified, reflecting broader climate change patterns. However, the correlation between rainfall and temperature was weak, indicating minimal direct interaction between these variables in the study areas. These results contribute valuable insights into climate dynamics and are critical for the development of climate change adaptation strategies in North Sumatra Province.
Prediksi Permintaan BBM Fasilitas Pegawai Menggunakan Simulasi Monte Carlo Pada PT. Pelabuhan Indonesia Regional I Dian Darmawan; Nova Audry Utami; Riri Syafitri Lubis
APPA : Jurnal Pengabdian Kepada Masyarakat Vol 3 No 2 (2025): APPA : Jurnal Pengabdian kepada Masyarakat (INPRESS)
Publisher : Shofanah Media Berkah

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

Abstract

Penelitian ini memprediksi kebutuhan Bahan Bakar Minyak (BBM) untuk karyawan PT Pelabuhan Indonesia Regional I selama tiga bulan ke depan (Desember 2024 – Februari 2025) menggunakan simulasi Monte Carlo. simulasi menunjukkan perkiraan konsumsi Solar sebesar 721,72 liter (Desember), 451,96 liter (Januari), dan 451,96 liter (Februari); serta Pertalite sebesar 442,14 liter (Desember), 425,26 liter (Januari), dan 425,26 liter (Februari). Metode ini diharapkan membantu PT Pelindo Regional I dalam mengoptimalkan pengeluaran BBM dan meningkatkan efisiensi operasional .Data konsumsi BBM (Solar dan Pertalite) September-November 2024 digunakan untuk membangun model prediksi
Optimizing Profit-to-Cost Ratios in Bakery Production Using the Hasan–Acharjee Fractional Programming Method Adisty, Fahliza; Lubis, Riri Syafitri
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.v10i2.35738

Abstract

Production optimization under resource constraints can be effectively modeled using Linear Fractional Programming (LFP), where the objective function is defined as a profit-to-cost ratio. This study applies the Hasan–Acharjee method to optimize production planning in a household-scale bakery enterprise in Indonesia, considering four product types and three resource constraints (materials, labor, and equipment). The model was reformulated as a single linear program and solved using LINGO 21.0. Validation against the classical Charnes–Cooper transformation confirmed identical optimal solutions, demonstrating the robustness of the Hasan–Acharjee approach. Sensitivity and trade-off analyses further revealed how variations in costs and production capacity influence profitability. The results highlight both the theoretical relevance of the Hasan–Acharjee method in fractional programming and its practical applicability to small and medium-sized enterprises seeking efficient resource utilization under limited conditions.
Maksimasi Keuntungan Layanan Jasa Be Clean Laundry Dengan Menerapkan Metode Branch And Bound Syahputra, Bayu Teza; Lubis, Riri Syafitri; Cipta, Hendra
Zeta - Math Journal Vol 6 No 2 (2021): November
Publisher : Universitas Islam Madura

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.31102/zeta.2021.6.2.1-5

Abstract

The purpose of this research is to find the maximize benefits from Be Clean Laundry business. In optimize laundry business by looking at the limited resources of the business used branch and bound method. Using the branch and bound method assisted by QM software in more optimal laundry, coat 53 kg, doll 32 kg, blanket 95 kg, bedcover 105 kg, gordyn 91 kg, and clothes 805 kg with a profit of Rp. 4.027.000, while the previous profit based on estimate made by the laundry Owner of Rp. 4.000.000 increase of 0,7 %.
Probabilistic Model of Back Order Policy on Dodol Pulut Raw Material Inventory Control With Linear Programming Br Siahaan, Erika Handayani; Riri Syafitri Lubis
KUBIK Vol 10 No 1 (2025): IN PRESS
Publisher : Jurusan Matematika, Fakultas Sains dan Teknologi, UIN Sunan Gunung Djati Bandung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.15575/kubik.v10i1.49121

Abstract

The high production costs of Dodol Pulut Raya further emphasize the importance of implementing a systematic, measurable, and effective inventory control strategy to maintain profitability, operational efficiency, and long-term business stability. This study applies the Probabilistic Back Order Policy Model combined with the Simplex Linear Programming method to determine the most optimal raw material management policy, taking into account demand uncertainty, supply variability, and the risk of stock shortages that could disrupt production smoothness. This approach comprehensively integrates precise safety stock calculations to minimize stockouts, reduce production delays, and ensure raw material availability so that customer needs can be consistently, timely, and sustainably met. The analysis results show that the implementation of this model can significantly reduce annual production costs from IDR 509,941,040 to IDR 338,719,300, resulting in cost efficiency of IDR 171,221,740 per year. This finding demonstrates the model's effectiveness in minimizing total inventory costs while enhancing competitiveness and operational sustainability. Additionally, this study provides a practical framework for small and medium-sized enterprises facing fluctuating demand, balancing service levels, safety stock, and overall cost optimization.
Optimizing the use of sewing materials to maximize production output Rakhmawati, Fibri; Rifki, Mhd Ikhsan; Husein, Ismail; Cipta, Hendra; Lubis, Riri Syafitri; Sari, Rina Filia
Abdimas Indonesian Journal Vol. 5 No. 2 (2025)
Publisher : Civiliza Publishing

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.59525/aij.v5i2.1043

Abstract

This Community Service Program aims to optimize the use of sewing materials to maximize production output at Rumah Jahit Nila through the application of a linear programming model in the allocation and use of sewing materials in planning and maximizing production output. The implementation methods include mapping processes and data requirements and formulating a linear programming model relevant to the scale of Nila Sewing House MSMEs, as well as training and live demonstrations using QM as software to determine optimization solutions. The evaluation was conducted on 15 participants using a 1–4 Likert scale instrument with four assessment indicators, namely, training content, presenter's subject-matter expertise, event facilities, and benefits of the program. Descriptive analysis showed an overall average of 3.43 on a scale of 4, with a percentage level of 85.8%, which is in the Very Good category. In order, the indicator achievements are Presenter’s Subject-Matter Expertise = 3.53 (88.33%), Benefits of the Program = 3.47 ( 86.67%), Training Content = 3.40 (85.00%), and Event Facilities = 3.33 (83.33%). These results confirm that the competence of the speakers and the relevance of the benefits are the main strengths, while the content and facilities of the activities are areas for priority improvement. This program has successfully improved participants' technical capacity in modeling and implementing linear program-based raw material optimization, while also providing a foundation for operational implementation to reduce waste and increase throughput.
Co-Authors Adisty, Fahliza Ahmad Sugarda Ainun Palihah Almira Amir Ananda, Lyra Anggi Pranata Annisa, Nur Alvi Aprilia, Rima Arjuna, Dimas Bagus Aslam, Fazri Aulia Turrizqiya Auliya Ramadhani, Dhea Batu, Annisa Rajaq Lumban Bella Syahrani Nasution Blaster, Irena Br Siahaan, Erika Handayani Cynthia, Mayang Modelina Dara Nurul Hasnah dewi, mutia hatina Dian Darmawan Didik Santoso Didik Santoso Dinda Renata Cecilia Dwi Haprida Ningsih Elma Dwi Ariana Aprilia Zam Elpita Sari Hasibuan Evi Borliana Siregar Fachrur Rozi Fadhliyah, Annisa Fadilatus Sahraini Siregar Fadillah, Yanna Rezki Fajriana, Fajriana Farwansyah, Mhd Rio Fatmawati, Ayu Isnaini Fernando, Anjas Fikri Husin Batubara Fuja Nauli Pasaribu Giawa, Freddy Gishela Agra Moukia Gurusinga, Ditha Aulia Harleni, Harleni Harleni, Silvia Hazizah, Salsabillah Hendra Cipta Heni Pujiastuti Ilham Salim Siregar Ilham Syaputra Indah Kholila Indah, Windi Rezeki Ir Zulkarnain, Ayu Najmita Binti Irena Blaster Ismail Husein, Ismail Kartika , Dinda Khairun Nikmah Latersia, Egya Dora Lisa Setia Ningsih M Agung Pradana Manurung, Silvi Khairiyah Maudya Nur Azura Mhd Ikhsan Rifki Mohammad Badri Muhammad Arfie Munawar Muhammad Farhan Mingka Muhammad Vikry Rezky Rambe Muliawan, Hari Nabilla, Widi Ihdina Nadhila, Nurul Nasution, Alfina Febriani Nasution, Dafa Al Qifti Nasution, Hamidah . Neliwati Neliwati Nenna Irsa Syahputri Nina Amanda nova audry utami Nurmadani Nurmawati Nurmawati Nurmawati Nurul Nadhila Nusantara, Badai Charamsar Oktaviana Oktaviana Palihah, Ainun Pertiwi, Fina Nur Pohan, Ahmad Syahrial Pohan, Siti Rolizah Pradana, M Agung Prasetya, Nurul Huda Pratiwi, Miftah Pulungan, Ahmad Fauzan Putri Harahap, Rahmelia Rahmat Darmawan, Rahmat Rakhmawati, Fibri Riani Dwi Lestari Ricka Afriani Rifki, Mhd Ikhsan Rima Aprilia Rima Aprilia Rina Filia Sari Rina Filia Sari, Rina Filia Rina Sari Filia Rina Widyasari Ritonga, Nurhalimah Rivani Kabrina Br Surbakti Rizkina, Ayu Rizky Mulyani Ropiqoh, Ropiqoh Ropiqoh, Ropiqoh Rusydi Ananda Ruth Mayasari Simanjuntak Sahraini Siregar, Fadilatus Sajaratud Dur Samsudin, Samsudin Sari, Evi Indah Serdano, Akbar Sintia Agustina Siregar Siregar, Evi Borliana Siregar, Fadilatus Sahraini Siregar, Tanti Jumaisyaroh Siti Jubaidah Siti Zunaida Nasution Suci Permata Sari Suendri, Suendri Sulaiman Ananda Harahap Supiah Supiah Susanti, Komaria Susilowati, Rahmi Suzana, Yenny Syafitri, Ellysa Syahfitri, Fatharani Syahputra, Bayu Teza Syahputri, Linna Syahputri, Nenna Irsa Syarah, Fatmah Tanti Jumaisyaroh Siregar Tri Amisri, Nurul Hasanah Tri Handayani Tri Lutfiah Wardah Turrizqiya, Aulia Utami, Destia Nada Utami, Ristika Dian Vani Hajari Wenny Marta Dolok Saribu Widyasari, Rina Widyasari, Rina Windi Rezeki Indah Wulandari Wulandari Wulandari, Mitha Yahfizham Yahfizham Yoffa Sunita Yulanda Novita Zebua Yulinda, Jeni Zahedi . Zakaria Alfikri Sirait Zam, Elma Dwi Ariana Aprilia