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All Journal Matematika: Jurnal Teori dan Terapan Jurnal Sains Dasar Martabe : Jurnal Pengabdian Kepada Masyarakat Jambura Journal of Mathematics International Journal of Research in Community Services International Journal of Quantitative Research and Modeling

Sudradjat Supian

Departemen Matematika, Fakultas Matematika Dan Ilmu Pengetahuan Alam, Universitas Padjadjaran

Author-ID : 1033052

Agriculture, Biological Sciences & Forestry Arts Humanities Computer Science & IT Decision Sciences, Operations Research & Management Economics, Econometrics & Finance Education Energy Engineering Environmental Science Mathematics Physics Social Sciences Other

Published : 18 Documents Claim Missing Document

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Prediction of Tourist Arrivals to the Island of Bali with Holt Method of Winter and Seasonal Autoregressive Integrated Moving Average (SARIMA) Agus Supriatna; Elis Hertini; Dwi Susanti; Sudradjat Supian
Jurnal Sains Dasar Vol 6, No 2 (2017): October 2017
Publisher : Faculty of Mathematics and Natural Science, Universitas Negeri Yogyakarta

The tourism sector is one of the contributors of foreign exchange is quite influential in improving the economy of Indonesia. The development of this sector will have a positive impact, including employment opportunities and opportunities for entrepreneurship in various industries such as adventure tourism, craft or hospitality. The beauty and natural resources owned by Indonesia become a tourist attraction for domestic and foreign tourists. One of the many tourist destination is the island of Bali. The island of Bali is not only famous for its natural, cultural diversity and arts but there are also add the value of tourism. In 2015 the increase in the number of tourist arrivals amounted to 6.24% from the previous year. In improving the quality of services, facing a surge of visitors, or prepare a strategy in attracting tourists need a prediction of arrival so that planning can be more efficient and effective. This research used Holt Winter's method and Seasonal Autoregressive Integrated Moving Average (SARIMA) method to predict tourist arrivals. Based on data of foreign tourist arrivals who visited the Bali island in January 2007 until June 2016, the result of Holt Winter's method with parameter values α=0.1 ,β=0.1 ,γ=0.3 has an error MAPE is 6,171873. While the result of SARIMA method with (0,1,1)〖(1,0,0)〗12 model has an error MAPE is 5,788615 and it can be concluded that SARIMA method is better.Keywords: Foreign Tourist, Prediction, Bali Island, Holt-Winter’s, SARIMA.

About Two Manners of Use Weighted Least Squares Approach in Fuzzy Statistics Ciprian Costin Popescu; Supian Sudradjat
Matematika Vol 7, No 1 (2008): Jurnal Matematika
Publisher : Universitas Islam Bandung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.29313/jmtm.v7i1.3365

Two fuzzy statistical models are generalized and extended to the weighted models. The new regression problems are solved and compared with the originals.

Probability distributions of COVID-19 tweet posted trends uses a nonhomogeneous Poisson process Devi Munandar; Sudradjat Supian; Subiyanto Subiyanto
International Journal of Quantitative Research and Modeling Vol 1, No 4 (2020)
Publisher : Research Collaboration Community (RCC)

The influence of social media in disseminating information, especially during the COVID-19 pandemic, can be observed with time interval, so that the probability of number of tweets discussed by netizens on social media can be observed. The nonhomogeneous Poisson process (NHPP) is a Poisson process with dependent on time parameters and the exponential distribution having unequal parameter values and, independently of each other. The probability of no accurence an event in the initial state is one and the probability of an event in initial state is zero. Using of non-homogeneous Poisson in this paper aims to predict and count the number of tweet posts with the keyword coronavirus, COVID-19 with set time intervals every day. Posting of tweets from one time each day to the next do not affect each other and the number of tweets is not the same. The dataset used in this study is crawling of COVID-19 tweets three times a day with duration of 20 minutes each crawled for 13 days or 39 time intervals. Result of this study obtained predictions and calculated for the probability of the number of tweets for the tendency of netizens to post on the situation of the COVID-19 pandemic.

Wireless Chaos-Based Communication System: Literature Review Siti Hadiaty Yuningsih; Sudradjat Supian; Sukono Sukono; Subiyanto Subiyanto
International Journal of Quantitative Research and Modeling Vol 2, No 1 (2021)
Publisher : Research Collaboration Community (RCC)

Since the early 1990s, a slew of chaotic-based communication systems have been proposed, all of which take advantage of chaotic waveform properties. The inspiration stems from the substantial benefits that this form of nonlinear signal offers. Many communication schemes and applications have been specifically designed for chaos-based communication systems to achieve this goal, with energy, data rate, and synchronization awareness being taken into account in most designs. However, non-coherent chaos-based systems have recently received a lot of attention in order to take advantage of the benefits of chaotic signals and non-coherent detection while avoiding the use of chaotic synchronization, which has poor performance in the presence of additive noise. This paper provides a thorough examination of all wireless radio frequency chaos-based communication systems. It begins by describing the difficulties of chaos implementations and synchronization processes, then moves on to a thorough literature review and study of chaos-based coherent techniques and their applications.

IDX30 Stocks Clustering with K-Means Algorithm based on Expected Return and Value at Risk Ahmad Fawaid Ridwan; Subiyanto Subiyanto; Sudradjat Supian
International Journal of Quantitative Research and Modeling Vol 2, No 4 (2021)
Publisher : Research Collaboration Community (RCC)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.46336/ijqrm.v2i4.157

Stocks are one of the investment instruments available in the capital market. Several indices show the characteristics of stocks listed on the Indonesia Stock Exchange. IDX30 is one of several indications that show the combined stocks are stocks with large market capitalization, high liquidity, and good fundamentals. The selection of assets to be allocated in the portfolio is an important factor in investing where the purpose of investing is to maximize returns and minimize risk. This study aims to classify stocks that have certain characteristics based on the expected return and value at risk of the stocks incorporated in IDX30 with a clustering algorithm. The clustering algorithm used is the K-Means algorithm. K-Means is a non-hierarchical clustering algorithm by groups each object based on its proximity to the cluster center. The method used in this research is a clustering simulation study using the K-Means algorithm on IDX30 stock data. By identifying the characteristics of the stock based on the characteristics of the cluster formed, it is hoped that it can be considered in choosing the assets to be used in the formation of an optimal portfolio.

Optimizing Stock Portfolio with Markowitz Method as a Reference for Investment Community Decisions Viona Prisyella Balqis; Subiyanto Subiyanto; Sudradjat Supian
International Journal of Research in Community Services Vol 2, No 2 (2021)
Publisher : Research Collaboration Community (RCC)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.46336/ijrcs.v2i2.213

An investor who wants to invest by avoiding risk makes investors tend to choose investments with the same expected return and the smallest or lowest possible risk. Therefore, investors expect to be able to maximize profits and minimize risk at the same time in investing. In a stock portfolio, it can be done by investing the funds owned by investors into several stocks so that it can reduce the risk of losses that will occur simultaneously. In choosing the right company to invest in with consideration of expected return and risk, a multi-objective optimization with multivariate objects can be used so that it can meet the expectations of investors. The portfolio concept introduced by Markowitz is a portfolio optimization intended for standard investors because it only refers to one explanation of portfolio returns. The Markowitz method can produce an optimal stock portfolio by considering the expected return and risk simultaneously so that the maximum profit can be obtained without eliminating the existing risk.

Utilizing MIKE 21 Software to Create Simple Hydrodynamic Simulations Subiyanto Subiyanto; Sudradjat Supian
International Journal of Research in Community Services Vol 2, No 1 (2021)
Publisher : Research Collaboration Community (RCC)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.46336/ijrcs.v2i1.156

This paper aim to create simple hydrodynamic simulation by using MIKE 21. The module used in MIKE 21 is LITPACK. LITPACK is one of the modules in MIKE 21 to solve hydraulic and sedimentation problems in coastal areas. Especially in this paper, the LITTLITE engine in LITPACK will be used. LITLINE determines the coastline position using a timeseries of wave climatic data. The model is based on a one-line theory, in which the cross-shore profile is expected to remain unaltered during erosion/accretion, with minor adjustments. Coastal morphology is thus only defined by coastline location (cross-shore direction) and coastal profile at a given long-shore position. The simulation used in this paper is the influence of groins on shoreline dynamics. The results of the simulation show that some areas will experience abrasion and some will experience accretion.

SOSIALISASI PADA MASYARAKAT KABUPATEN PANGANDARAN MENGENAI BAHAYA MEMBUANG SAMPAH DI SUNGAI Sudradjat Supian; Hazman Hiwari; Subiyanto Subiyanto
Martabe : Jurnal Pengabdian Kepada Masyarakat Vol 3, No 1 (2020): Martabe : Jurnal Pengabdian Kepada Masyarakat
Publisher : Universitas Muhammadiyah Tapanuli Selatan

Garbage is one of the problems that often occur in the community, especially in the disposal and handling of its existence. The Integrative KKNM-PPMD activity is a form of community service which based on Tridharma state of universities, can be used as a small deterrent to introduce and encourage clean action to the community to maintain the cleanliness of the environment. The purpose of this study is to educate the public about the dangers of dumping activities in the river. The activities carried out in 2 methods—first, socialization in the form of delivering information about the dangers of littering. Second, clean action activities participated in all communities around the Cikidang river. Implementation of this activity, it is expected the community can care about the cleanliness of the environment, including the river area.

Systematic Literature Review on Troubleshooting Delivery of Production Product Using n-Vehicle with Vogel Total Difference Approach Method Al Fataa Waliyyul Haq; Sudradjat Supian; Diah Chaerani
Jambura Journal of Mathematics Vol 4, No 2: July 2022
Publisher : Department of Mathematics, Universitas Negeri Gorontalo

The product delivery strategy using n-vehicle is the application of optimization for transportation problems. The product delivery strategy using n-vehicle is useful for minimizing the shipping costs of a company’s production. This article presents a peer-reviewed bibliometric analysis based on the topic of production delivery strategies using n-vehicle. Overall, there are 91 articles from the Dimension, Science Direct, and Google Scholar databases in 2013-2021 that use the topic of production delivery strategies using n-vehicle based on the keywords ”Capacitated transportation problem” and ”cost” and ”vehicle” and” optimal solutions”. The researcher presents the relationship of each cited article so that it can show the collaboration of all the cited articles. This article aims to generate and review analysis results through Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) and State of The Art. Bibliometric analysis, PRISMA, and State of The Art show how the development of research on production delivery strategies using n-vehicle. So, it can produce suggestions in conducting the latest research related to studies on the topic of production delivery strategies using n-vehicle. Based on PRISMA’s analysis, 91 articles were obtained, of those 91 articles, 11 articles discussed the strategy of delivering production products using n-vehicle in depth. The State of The Art also shows how the development of research on production delivery strategies using n-vehicle is developing. It can be seen that apart from the classical method, other methods are also emerging to solve transportation problems. One of them is Vogel Total Difference Approach Method (VTDM).

Measuring the Water Surface Speed of the Cikidang River as a Supporting Facility for the Development of Ecotourism Areas Subiyanto Subiyanto; Sudradjat Supian; Yuyun Hidayat; Triyani Hendrawati
International Journal of Research in Community Services Vol 3, No 3 (2022)
Publisher : Research Collaboration Community (RCC)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.46336/ijrcs.v3i3.333

Pangandaran Regency is famous for its natural beauty, especially the beauty of its beaches. In this district there are many famous beaches. Besides the beach, there are also rivers that offer beautiful views. However, not many tourists have made the rivers in Pangandaran as tourist destinations, especially the Cikidang River. Cikidang River has the potential to be used as ecotourism. In building an ecotourism area on the banks of a river, it is necessary to carry out an in-depth analysis of the damage that might occur due to erosion. One of the factors that can increase erosion is the speed of water on the surface. Therefore, in this paper, measurement of river surface velocity is carried out in a simple way and analyzed using the velocity formula. From the results of this measurement, a recommendation was made to direct all parties involved in measuring the surface velocity of the Cikidang River as a means of supporting the development of ecotourism areas.

Co-Authors Agus Ismangil Agus Supriatna Ahmad Fawaid Ridwan Al Fataa Waliyyul Haq Asep Saepulrohman Ayun Sri Rahmani Ciprian Costin Popescu Devi Munandar Diah Chaerani Dita Aulia Nissa Dwi Susanti Elis Hertini Hazman Hiwari Julita Nahar Mohammad Fadhli Ahmad Rizki Apriva Hidayana Subiyanto Subiyanto Subiyanto Subiyanto Subiyanto Subiyanto Sukono Sukono Triyani Hendrawati Viona Prisyella Balqis Wahyu Gendam Prakoso Yuningsih, Siti Hadiaty Yuyun Hidayat

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