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All Journal BAREKENG: Jurnal Ilmu Matematika dan Terapan Mandalika Mathematics and Educations Journal Contemporary Mathematics and Applications (ConMathA)
Nurcahya Yulian Ashar
Department Of Mathematics, Faculty Of Sciences And Mathematics, Universitas Diponegoro, Indonesia
Computer Science & IT Control & Systems Engineering Economics, Econometrics & Finance Energy Engineering Materials Science & Nanotechnology Mathematics Mechanical Engineering Physics Transportation

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A NUMERICAL STUDY OF SUBSTANCE SPREAD IN THE POLL FROM TWO POINT SOURCES Ashar, Nurcahya Yulian; Hariyanto, Susilo
BAREKENG: Jurnal Ilmu Matematika dan Terapan Vol 17 No 1 (2023): BAREKENG: Journal of Mathematics and Its Applications
Publisher : PATTIMURA UNIVERSITY

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (474.08 KB) | DOI: 10.30598/barekengvol17iss1pp0009-0020

Abstract

Problems related to the purification of holding pool or reservoir become an interesting discussion in real events. In this paper, the author will modeling the distribution of the substance/purifier in a pool model with turbulent water flow using the diffusion-convection equation. The Dual Reciprocity Method is applied to the diffusion-convection equation whose derivation will be discussed in this paper. This method is chosen because the problem cannot be solved analytically, so it must be solved numerically. The Dual Reciprocity Method has good flexibility in problems of water infiltration, pollutant spread, and heat transfer. In this paper also discuss velocity profile of turbuelent flow from upcoming part of pool region. So before using DRM, will be used numerical solution of turbulent flow by k-epsilon turbulent model. In numerical calculations, two source points are selected whose positions are combined to see the most effective way to make the substance/purifier evenly distributed in the pool.
Forecasting the Consumer Price Index in Banyumas Regency Using Double Exponential Smoothing with Proportional Integral Derivative Controller Ashar, Nurcahya Yulian; Abiyyin, Maulana Fatih
Contemporary Mathematics and Applications (ConMathA) Vol. 7 No. 2 (2025)
Publisher : Universitas Airlangga

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20473/conmatha.v7i2.74764

Abstract

The Consumer Price Index (CPI) is a crucial measure of inflation and the cost of living within a specific region. Accurate CPI forecasts are essential for policymakers, businesses, and stakeholders to make informed decisions. This study utilizes the Double Exponential Smoothing (DES) method to forecast the CPI for Banyumas Regency in January 2025, employing monthly CPI data from January 2020 to December 2024. The DES method was selected due to the observed upward trend in historical CPI data. Python programming was employed to optimize the smoothing parameters α and β, and the results were evaluated using Mean Absolute Deviation (MAD), Mean Squared Error (MSE), and Mean Absolute Percentage Error (MAPE). The forecasted CPI for January 2025 is 106.36, with high accuracy indicators, including a MAPE of 0.26%, demonstrating that DES is a reliable model for CPI forecasting in Banyumas Regency.
Analisis Pengendalian Kualitas Produk Telur Asin menggunakan Peta Kontrol P-Chart di UMKM HTM Jaya Brebes Ashar, Nurcahya Yulian; Rosyadi, Humam; Nabilah, Zizka Syaikhahtun
Mandalika Mathematics and Educations Journal Vol 7 No 3 (2025): Edisi September
Publisher : FKIP Universitas Mataram

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.29303/jm.v7i3.9939

Abstract

This study aims to analyze product quality control using the P-chart control chart method at UMKM HTM Jaya Brebes, a small business that produces salted eggs in Brebes, Central Java. A total of 20,582 eggs were observed during the production process in July 2024, with a total of 1,039 defective units. The study uses Statistical Quality Control (SQC) tools such as control limits (UCL and LCL) and quality cost analysis. The P-chart was used to monitor and evaluate the proportion of defective products, identifying several points outside the control limits, indicating a lack of process stability. Additionally, fishbone diagrams were used to analyze root causes of defects such as shell damage and freshness issues. The analysis also included quality cost optimization, showing the importance of balancing quality assurance and control costs to improve product efficiency. The findings emphasize that P-chart implementation can help small industries enhance product quality and maintain consumer satisfaction.
Co-Authors Abiyyin, Maulana Fatih Nabilah, Zizka Syaikhahtun Rosyadi, Humam susilo hariyanto