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Prediksi Rata-Rata Harga Emas 24 Karat Di Kota Medan Dengan Metode Arima Marlina, Wenni; Dongoran, Raisha zuhiara; Kinanti, Tri; Ginting, Iren Salsalina Br; Widyasari, Rina
JURNAL JENDELA MATEMATIKA Vol. 3 No. 02 (2025): Jurnal Jendela Matematika: Edisi Juli 2025
Publisher : CV. Jendela Edukasi Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.57008/jjm.v3i02.1634

Abstract

Fluktuasi harga emas yang dipengaruhi oleh berbagai faktor ekonomi global dan domestik mendorong pentingnya prediksi harga yang akurat sebagai dasar pengambilan keputusan investasi. Penelitian ini bertujuan untuk memodelkan dan memprediksi harga emas 24 karat di Kota Medan dengan menggunakan metode Autoregressive Integrated Moving Average (ARIMA). Data yang digunakan merupakan data sekunder bulanan dari Januari 2020 hingga Desember 2023 yang diperoleh dari BPS Kota Medan. Melalui tahapan identifikasi stasioneritas, estimasi parameter, dan uji diagnostik model, ditemukan bahwa model terbaik adalah ARIMA (1,2,1). Model ini menunjukkan nilai Mean Absolute Percentage Error (MAPE) sebesar 9,13%, yang mengindikasikan tingkat akurasi prediksi yang sangat baik. Hasil prediksi menunjukkan tren kenaikan harga emas sepanjang tahun 2024, dengan nilai tertinggi mencapai Rp1.109.817 pada bulan Desember. Temuan ini diharapkan dapat memberikan informasi strategis bagi masyarakat dan investor dalam merencanakan investasi emas yang lebih bijak.
INTERPOLATION METHODS ELANDT-JOHNSON TO ESTIMATE THE COMPLETE MORTALITY TABLE OF THE INDONESIAN YOUTH POPULATION BASED ON THE MORTALITY TABLE COALE-DEMENY Riningsih, Novia; Widyasari, Rina; Husein, Ismail
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/barekengvol19iss4pp3005-3018

Abstract

The growth of the productive age population has continued to increase since 1971 and looks more significant in 2020. In 2010, the youth age group (16-30 years) reached 62.343.755. The population consists of 31.244.215 men and 31.099.540 women. In 2020, the youth age group will increase to 64.470.655 people, with 32.949.184 men and 31.529.270 women. The number of male youth is greater than the number of female youth. However, in 2020, youth health conditions worsened. Many young people experience severe stress and commit suicide due to depression. This will be one of the causes of the decline in young people in Indonesia. Since the Elandt-Johnson interpolation method provides reliable estimates for adult mortality, this study aims to obtain a more accurate, complete life table for Indonesian youth by applying the Elandt-Johnson interpolation method based on the Coale-Demeny West model a-bridged life table, using secondary data from the 2010 and 2020 Population Censuses provided by Statistics Indonesia. From the research results, it is known that the number of young men who survive until the age of 30 is 94.444 and young women who survive until the age of 30 is 95.724, meaning that the number of young women who survive is higher than young men, this means that the number of deaths of young men is higher than that of young women.
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.
Utilization of Betel Leaf Extract as a Natural Hand Sanitizer to Prevent The Spread of Covid-19 in MTS. S Al-Hidayah, Silo Baru Village, Asahan Regency Syafitriani; Novianti; Andayani; Widyasari, Rina; Husein, Ismail
ABDIMAS TALENTA: Jurnal Pengabdian Kepada Masyarakat Vol. 7 No. 1 (2022): ABDIMAS TALENTA: Jurnal Pengabdian Kepada Masyarakat
Publisher : Talenta Publisher

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (749.11 KB) | DOI: 10.32734/abdimastalenta.v7i1.6839

Abstract

Betel leaf (Piper betle Linn) can be found in Silo Baru Village, Silau Laut District, Asahan Regency. This service activity aims to increase public knowledge about the content of betel leaf extract compounds as natural hand sanitizers, improve community skills in processing traditional betel leaf plants, and produce environmentally friendly hand sanitizer products made from betel leaf. Betel leaf, known as a natural antiseptic, analgesic and anti-inflammatory. Betel leaf extract contains flavonoid compounds, polyphenols, tannins and essential oils that can eradicate disease-causing germs. The content of compounds in betel leaf extract 15% and above is as effective as 70% ethanol which can reduce the number of bacteria and viruses. This activity is carried out using mentoring and training methods. The results of this activity include producing a natural hand sanitizer product that can support government programs in preventing the spread of the covid-19 virus, increasing local community knowledge through students and several teachers at MTs.S Al-Hidayah who participate in mentoring on how to manage and the introduction of the content of betel leaf extract to be used as the main ingredient in making natural hand sanitizers.
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.
POPULATION PROJECTION AND FACTOR ANALYSIS AFFECTING POPULATION GROWTH IN THE CITY MEDAN USING NON LINEAR TRENDS POLYNOMIC METHOD Pertiwi, Fina Nur; 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.v2i1.47

Abstract

Non-linear trend is a measure of trend that has a model with quadratic equations, cubic and so on. The purpose of this research is to determine the population projection in Medan using a non-linear trend of the polynomial method (parabolic trend / quadratic trend) and to determine the factors that influence population growth in the city of Medan. From the results of data processing using the non-linear trend of the polynomial method, it is obtained that the projected number of population in 2029 will be 2645501 people, with The total male population is 1314713 and the female population is 1330788. When compared with the population in previous years, it can be seen that until 2029 the population in Medan will increase. Based on the research results from the factor analysis, it is known that the factors that are formed from the factor analysis process can be concluded that all the factors formed affect the population growth rate of Medan. The factors formed are birth (fertility), death (mortality) and migration.
FORECASTING THE NUMBER OF COVID-19 SUFFERERS IN NORTH SUMATRA USING THE AUTOMATIC CLUSTERING FUZZY TIME SERIES MARKOV CHAIN METHOD Siregar, Anggi Ramadany; Sari, Rina Filia; Widyasari, Rina
Journal of Mathematics and Scientific Computing With Applications Vol. 2 No. 2 (2021)
Publisher : Pena Cendekia Insani

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.53806/jmscowa.v2i1.48

Abstract

Corona virus is a virus that is currently endemic throughout the world, including in Indonesia, one of which is in North Sumatra Province, because this virus has claimed many victims. North Sumatra Province in positive cases of Covid-19 is ranked 13th out of 34 provinces in Indonesia. The government's anticipation in handling Covid-19 cases is by forecasting the number of positive Covid-19 cases. One of the methods used to forecast Covid-19 sufferers is the Automatic Clustering Fuzzy Time Series Markov Chain method. The Fuzzy Time Series Markov Chain method is used to resolve the deviation value from a forecasted value, while Automatic Clustering is used to determine the length of the interval by grouping numerical data. Then the error calculation will be carried out using the Mean Absolute Percentage Error (MAPE) to determine the level of accuracy of the forecasting model that has been made. The parameter used in this study is the number of Covid-19 sufferers. The results of this study from data on the number of Covid-19 sufferers have a MAPE value of 4.53%. The MAPE value which is less than 10% means that the forecasting of this study has very good criteria. So the Automatic Clustering Fuzzy Time Series Markov Chain method is very good to be applied in forecasting the number of Covid-19 sufferers in North Sumatra Province.
PREDICT THE PRICE OF CURLY RED CHILI IN NORTH SUMATRA USING THE HOLT WINTERS ADDITIVE METHOD Nurainun, Umi Sarah; Dur, Sajaratud; Widyasari, Rina
Journal of Mathematics and Scientific Computing With Applications Vol. 2 No. 2 (2021)
Publisher : Pena Cendekia Insani

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.53806/jmscowa.v2i1.49

Abstract

Curly red chilies are one of the vegetable commodities that have an effect on national economic growth. North Sumatra is one of the largest red chilli have a problem with price fluctuations which will result in inflanation. Erratic chili prices will have an impact on society and the country. The right policy to avoid negative impact on price fluctuations of North Sumatra’s curly red chilies is to predict it in the future. The purpose of this study was to obtain the result of the prediction of the price of North Sumatra curly red chilies. The results of this analysis can be used in determining the right policy. The method used in this study is the Holt Winters Additive Method, because the Holt Winters Additive Method is a method that can be used for forecasting data that has elements of trend and seasonality. The data used in this study is the average price of North Sumatra curly red chilies per week from January 2020 to February 2021 which is obtained from the National Strategic Food Price Information Center. After testing the price of curly red chilies in North Sumatra, a forecast data plot is obtained which tends to follow the actual data. Then the error rate is measured using MAPE (Mean Absolute Percentage Error). The MAPE results obtained were 10.15% with the best parameters ? = 0.84, ? = 0.09 and ? = 0.83. this means that the Holt Winters Additive method has a good level of accuracy used to predict the price of curly red chilies in North Sumatra Province.
APPLICATION OF LEAN SIX-SIGMA METHOD AND DEMERIT CHART TO MINIMIZE DEFECTIVE PRODUCT Novia, Ayu; Sari, Rina Filia; Widyasari, Rina
Journal of Mathematics and Scientific Computing With Applications Vol. 2 No. 2 (2021)
Publisher : Pena Cendekia Insani

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.53806/jmscowa.v2i1.51

Abstract

uality control is a form of inspection using certain techniques or methods in decision-making to get the quality standards that have been determined. One type of quality control is using the method of Lean Six Sigma to identify and eliminate waste in activities that are not worth the added value through a continuous increase to reach the level of Six Sigma, then use the demerit control chart as a monitor of the production process. The purpose of the study was to find out how to minimize defects in the 220ml Aqua cup mineral water packaging with the method of Lean Six Sigma and Demerit control chart. With the analysis that has been done, it is known that in the 220ml Aqua Cup product the DPMO value for defects in the 220ml AQUA Cup production process is 22912.83, which is the level of sigma is 3.43 and the process capabilities value is 0.77087 which mean that it still needs a process control for minimizing the product defects.