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All Journal Jurnal Perikanan Kelautan Berkala Perikanan Terubuk Indonesian Journal of Forestry Research Omni-Akuatika Martabe : Jurnal Pengabdian Kepada Masyarakat PAPALELE : Jurnal Penelitian Sosial Ekonomi Perikanan dan Kelautan International Journal of Research in Community Services International Journal of Quantitative Research and Modeling

Subiyanto Subiyanto

Departemen Ilmu Kelautan, Fakultas Perikanan Dan Ilmu Kelautan, Universitas Padjadjaran

Author-ID : 3399762

Agriculture, Biological Sciences & Forestry Arts Humanities Biochemistry, Genetics & Molecular Biology Computer Science & IT Decision Sciences, Operations Research & Management Earth & Planetary Sciences Economics, Econometrics & Finance Education Energy Engineering Environmental Science Physics Social Sciences Other

Published : 18 Documents Claim Missing Document

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Articles

Title

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.

Robust Optimization for Food Supply Chain Management Problems: A Critical Review and its Novelty Athaya Zahrani Irmansyah; Subiyanto Subiyanto
International Journal of Quantitative Research and Modeling Vol 2, No 3 (2021)
Publisher : Research Collaboration Community (RCC)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.46336/ijqrm.v2i3.155

Optimization problems in real life often have problems with data that cannot be known precisely; constraints on the data are commonly referred as errors. This kind of data is called uncertainty. This uncertainty problem can be solved using Robust Optimization (RO). RO is growing rapidly with the participation of various kinds of research, especially the supply chain (distribution of food or goods between regions). It can be seen that RO is very active in providing support and contribution in various aspects of life by providing optimal results for an objective function and dealing with existing limitations and data uncertainty. This article discusses the background of the problem and the purpose of creating an article, provides an overview of bibliometric map analysis methods and discusses literature and studies. Critical review from OR database articles for supply chain problems are used as a reference, so at the end, it can be determined what novelty is an opportunity for further research.

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.

SHELF LIFE OF NORI FROM Gracilaria sp. WITH ALUMUNIUM FOIL PACKAGING BASED ON THE ACCELERATED SHELF LIFE TEST METHOD Evi Liviawaty; Sapinatun Namira; subiyanto subiyanto; Eddy Afrianto
International Journal of Quantitative Research and Modeling Vol 2, No 1 (2021)
Publisher : Research Collaboration Community (RCC)

This research was conducted at the Laboratory of Fisheries Products Processing, Faculty of Fisheries and Marine Sciences, Padjadjaran University, Jatinangor. The purpose of this research is to determine the shelf life of Nori from Gracilaria sp. with the Accelerated Shelf Life Test (ASLT) method Arrhenius Model using Aluminum Foil packaging. Aluminum foil packaging is a package composed of hermetic, flexible, and opaque metal so that it has high protection properties against water vapor, light, grease and gas. The determination of the shelf life of the ASLT method is carried out using parameters of environmental conditions that can accelerate the process of product quality degradation, namely by storing the product at several temperatures above normal storage temperature. The observations used in determining the shelf life of Gracilaria sp. using a sensory test and a water content test with storage for 35 days, at a temperature of 25oC and 35oC. The result of the Arrhenius model calculation, the appearance parameter is selected as the critical parameter because it has the lowest Activation Energy (Ea) in determining the shelf life of Gracilaria sp. which is packaged using PE plastic. The results show that the parameters used to determine the shelf life of the product are the taste parameters based on the order 1 reaction with the Arrhenius Plot Ln K = 0.026 – 1318.4 (1 / T) and Ea of 2619.66 Kj/mol. The shelf life of Nori Gracilaria sp. if stored at 25oC temperature is 89 hari 7 jam.

Sediment Transport Pattern Modelling in Bojong Salawe Coast Pangandaran using Mike 21 Nira Nirwana; Subiyanto Subiyanto; Yuniarti MS; Yudi Nurul Ihsan
International Journal of Quantitative Research and Modeling Vol 2, No 2 (2021)
Publisher : Research Collaboration Community (RCC)

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (1451.011 KB)

Bojong Salawe is a coastal area with unique characteristics due to a confluence of three rivers that flow through Cijulang, Cijalu, Cialit and into the Indian Ocean. With complex oceanographic conditions, the sediment transport patterns at Bojong Salawe needs to be contemplated, especially the coastal’s utilization which is quite productive. This study aims to determine the sediment types, the sediment transport patterns and the effect of sediment transport on abrasion or accretion which are supported by hydrodynamic parameters modelling such as wind, currents and tides in the west and east monsoons using hydrodynamic modules and sediment transport in MIKE 21. The results showed that the sediments in this study is 80% sandy silt and 20% sand. The sediment transport pattern models in both the west and east monsoons tend to be influenced by tidal currents, sediment types and the season itself. West monsoon has a higher sediment concentration which ranges from 0 to 8.4 kg/m3 compared to the East Monsoon with a range of 0-4 kg/m3. The effect of sediment transport on the average bed level was 0.71861 m in the west monsoon and 0.37586 m in the east monsoon whereas in the estuary (research station), the average change in West Monsoon is 0.00861 m (ST 1) and 0.07107 m (ST 2) and in the East Monsoon, it is 0.01003 m (ST 1) and 0.01147 m (ST 2). This bed level change tends to increase, indicating that the Bojong Salawe coast has experienced sedimentation (accretion).

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.

Co-Authors Abdurrahman Al Farrizi Agus Ismangil Ahmad Fawaid Ridwan Andre Wijaya Ankiq Taofiqurohman Asep Saepulrohman Athaya Zahrani Irmansyah Atikah Nurhayati Chay Asdak Devi Munandar Dhika Surya Pangestu Eddy Afrianto Evi Liviawaty Fikri Nashrullah Handaka, Asep Agus Hazman Hiwari Junianto Junianto Muhamad Satrio Legowo Nira Nirwana Rizki Apriva Hidayana Rusky Intan Pratama Sapinatun Namira Sudradjat Sudradjat Sudradjat Supian Sudradjat Supian Sudradjat Supian Sudradjat Supian Sudradjat Supian Sudradjat Supian Sudradjat Supian Sukono . Titi Purwandari Viona Prisyella Balqis Wahyu Gendam Prakoso Wahyuniar Pamungkas Yudi Nurul Ihsan Yulizar Yulizar Yuniarti MS Yuningsih, Siti Hadiaty Yuyun Hidayat

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