Article Per Year (5 Year)
p-Index From 2021 - 2026
14.799
P-Index
This Author published in this journals
All Journal 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 Euler : Jurnal Ilmiah Matematika, Sains dan Teknologi FARABI: Jurnal Matematika dan Pendidikan Matematika 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 Educational Journal
Riri Syafitri Lubis
Universitas Islam Negeri Sumatera Utara, Medan, Indonesia
Religion Agriculture, Biological Sciences & Forestry Humanities Biochemistry, Genetics & Molecular Biology Chemical Engineering, Chemistry & Bioengineering Chemistry Civil Engineering, Building, Construction & Architecture Computer Science & IT Control & Systems Engineering Decision Sciences, Operations Research & Management Earth & Planetary Sciences Economics, Econometrics & Finance Education Electrical & Electronics Engineering Energy Engineering Environmental Science Health Professions Industrial & Manufacturing Engineering Languange, Linguistic, Communication & Media Law, Crime, Criminology & Criminal Justice Library & Information Science Materials Science & Nanotechnology Mathematics Mechanical Engineering Medicine & Pharmacology Physics Public Health Social Sciences Transportation Other

Published : 110 Documents Claim Missing Document
Claim Missing Document
Check
Articles

Found 110 Documents
Search

 7   8   9   10   11 
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.
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.
Penerapan Logika Fuzzy Pada Pengendalian Mutu Minyak Kelapa Sawit dengan Metode Statistical Quality Control di PKS Ptpn II Pagar Merbau Auliya Ramadhani, Dhea; Lubis, Riri Syafitri; Widyasari, Rina
Proximal: Jurnal Penelitian Matematika dan Pendidikan Matematika Vol. 8 No. 4 (2025): Volume 8 Nomor 4 Tahun 2025
Publisher : Universitas Cokroaminoto Palopo

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.30605/proximal.v8i4.7151

Abstract

Pengendalian mutu Crude Palm Oil (CPO) merupakan faktor krusial untuk menjaga standar kualitas dan daya saing PKS PTPN II Pagar Merbau. Metode konvensional seperti Statistical Quality Control (SQC) umum digunakan untuk memantau stabilitas proses produksi melalui peta kendali. Namun, SQC memiliki keterbatasan dalam menangani data yang bersifat ambigu atau samar (ketidakpastian) karena pendekatannya yang crisp (tegas), yang hanya mengklasifikasikan status proses sebagai "terkendali" atau "di luar kendali". Penelitian ini bertujuan untuk merancang dan mengimplementasikan sistem pengendalian mutu CPO dengan mengintegrasikan metode SQC dan Logika Fuzzy. Penelitian ini menggunakan data parameter mutu utama CPO, seperti Asam Lemak Bebas (ALB), Kadar Air , dan Kadar Kotoran yang dianalisis terlebih dahulu menggunakan peta kendali SQC untuk menentukan batas-batas kontrol statistik. Selanjutnya, data tersebut dijadikan variabel input untuk Sistem Inferensi Fuzzy (FIS). Logika Fuzzy digunakan untuk memetakan data input yang ambigu ke dalam himpunan fuzzy (misalnya: Rendah, Normal, Tinggi) dan memprosesnya melalui basis aturan (IF-THEN) untuk menghasilkan output kualitatif berupa status mutu CPO (misalnya: Sangat Baik, Baik, Cukup, Buruk). Hasil penelitian menunjukkan bahwa penerapan Logika Fuzzy mampu memberikan penilaian status mutu yang lebih fleksibel, adaptif, dan informatif dibandingkan metode SQC murni. Sistem ini dapat memberikan peringatan dini yang lebih sensitif terhadap pergeseran kecil dalam proses, sehingga membantu manajemen PKS PTPN II Pagar Merbau dalam mengambil keputusan korektif yang lebih cepat dan tepat untuk menjaga konsistensi mutu CPO.
BLACK TEA GRADE CLASSIFICATION USING PROBABILISTIC NEURAL NETWORK (PNN) Sari, Evi Indah; Prasetya, Nurul Huda; Lubis, Riri Syafitri
Journal of Mathematics and Scientific Computing With Applications Vol. 2 No. 1 (2021)
Publisher : Pena Cendekia Insani

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.53806/jmscowa.v2i1.42

Abstract

North Sumatera tea is known as black tea, one which is produced by PT Perkebunan Nusantara IV Unit Bah Butong which produce 16 types of black tea. This research aims to classify black tea grades using Probabilistic Neural Network method and determine the accuracy value of black tea classification using Probabilistic Neural Network method. Data used are data of characteristics of 16 black tea types with the attributes id, types of tea, colour density, particel weight, particel size and particel shape. To get the best accuracy result, training data and testing data are divided using K-Means Clustering. Futhermore, classificy the testing data using Probabilistik the result obtained a grade 1 classification class totaling 7 records with a brownish black appearance and granutes particel, grade 2 totalling 7 record with a beownish appearance and grade 3 totaling 2 records with reddish appearance and not determine its shape and obtain an accuracy value of 80,00%.
ANALYSIS OF THE VISIT RATE AT THE IRIAN MARELAN SUPERMARKET DURING THE COVID-19 PANDEMIC Kartika , Dinda; Lubis, Riri Syafitri; Widyasari, Rina
Journal of Mathematics and Scientific Computing With Applications Vol. 2 No. 1 (2021)
Publisher : Pena Cendekia Insani

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.53806/jmscowa.v2i1.44

Abstract

Currently our country is experiencing a disaster due to a very dangerous virus that has claimed many lives or commonly referred to as COVID-19. The government had limited the operating hours of public places to prevent the spread of the virus. This has resulted in disruption of economic activities, one of which is the Irian Supermarket & Dept Store. This research was conducted to determine how the level of visits to Irian with the Spearman Rank Correlation method. From the results of the Spearman Rank correlation analysis carried out, the calculated value is 0.307 with a positive sign which indicates a low level of relationship and it is concluded that the level of visits is not influenced by the application of health protocols but is influenced by facilities and sales techniques, This can also be seen in the results of the t-test. The result of count obtained is 3.20 shows that the variable level of visits has a significant correlation with purchasing decisions.
M/G/1 QUEUE WITH SINGLE WORKING VACATION AND VACATION INTERRUPTION TO THE EXPECTED VALUE OF MANY CUSTOMERSAT BANK MUAMALAT SUKARAMAI SUB-BRANCH OFFICE Susilowati, Rahmi; Lubis, Riri Syafitri; Widyasari, Rina
Journal of Mathematics and Scientific Computing With Applications Vol. 2 No. 1 (2021)
Publisher : Pena Cendekia Insani

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.53806/jmscowa.v2i1.46

Abstract

Queuing occurs because the number of customers who arrive exceeds the service capacity, so customers have to queue to be served. A working vacation is a server serving at a slower speed. The server can return to a busy period with a (vacation interruption) opportunity or continue a vacation with a opportunity, with the single working vacation and vacation interruption method. The objective of this study is to obtain the effect of service rate and the expected value of the number of customers in the system after the departure of one customer and minimize operating costs during the vacation period (pause). The M / G / 1 queue study with Single Working Vacation and Vacation Interruption found that the average arrival rate (?) was 0.069 and the average service rate was 1.5 with the average vacation time (?) was 0, 41 and the average value of the expected number of customers in the system is 0,19 and for operating costs it can also be drunk to -16,38. This means that the queuing system is not efficient, due to the low level of server activity and the expected value of the number of customers in the system is 0 or there are no customers waiting in the system.
Co-Authors Ahmad Sugarda Ainun Palihah Almira Amir Ananda, Lyra Anggi Pranata Annisa, Nur Alvi 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 Dedy Juliandri Panjaitan 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 Hasibuan, Hani Maulida 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 Kurahman, Panca Taufik Latersia, Egya Dora Lisa Setia Ningsih M Agung Pradana Manurung, Silvi Khairiyah Maudya Nur Azura Mhd Ikhsan Rifki Mohammad Badri Muhamar Chaniago, Febri 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, Fakhrur Rozi Nasution, Fakhrur Rozi 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 Rahayu, Sri Ulfa Rahma Miyati Rahmat Darmawan, Rahmat Rakhmawati, Fibri Riani Dwi Lestari Ricka Afriani 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 Silvia Harleni Simamora, Devitasari Sintia Agustina Siregar Siregar, Evi Borliana Siregar, Fadilatus Sahraini Siregar, Tanti Jumaisyaroh Siti Jubaidah Siti Zunaida Nasution Suci Dahlya Narpila, Suci Dahlya 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 Tanjung, Aida Febriana 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 Zam, Elma Dwi Ariana Aprilia