http://jims-a.org/index.php/jimsa/issue/feed Journal of the Indonesian Mathematical Society 2021-12-10T15:54:37+00:00 Editorial jims.indoms@gmail.com Open Journal Systems <div><strong>Journal title</strong> : Journal of The Indonesian Mathematical Society</div> <div><strong>Initials</strong> : JIMS</div> <div><strong>Abbreviation</strong> : J. Indones. Math. Soc.</div> <div><strong>Frequency</strong> : 3 issues per year (March, July, and November)</div> <div><strong>DOI prefix</strong> : <a href="https://search.crossref.org/?q=2086-8952">10.22342</a> by<img src="https://jims-a.org/public/site/images/admin/crossref-logo-stacked-rgb-small-a41f52ed695a710d6a57355cc9ee7d7c.png" alt="" width="52" height="14" /></div> <div><strong>Print ISSN</strong> : <a href="http://u.lipi.go.id/1274193789">2086-8952</a></div> <div><strong>Online ISSN</strong> : <a href="http://u.lipi.go.id/1432110804">2460-0245</a></div> <div><strong>Editor-in-chief</strong> : <a href="https://www.scopus.com/authid/detail.uri?authorId=16053675900">Indah Emilia Wijayanti</a></div> <div><strong>Executive Editor</strong> : <a href="https://www.scopus.com/authid/detail.uri?authorId=24480624100">Fajar Adi Kusumo</a></div> <div><strong>Managing Editor</strong> : <a href="https://www.scopus.com/authid/detail.uri?authorId=57050754900">Hazrul Iswadi</a></div> <div><strong>Publisher</strong> : <a href="https://indoms.id/en/home/">The Indonesian Mathematical Society</a></div> <div><strong>Citation Analysis</strong> : <a href="http://sinta2.ristekdikti.go.id/journals/detail?id=3739">SINTA</a> | <a href="https://suggestor.step.scopus.com/progressTracker/?trackingID=224BA6482DB848A3">Scopus</a> | <a href="https://scholar.google.co.id/citations?hl=id&amp;btnA=1&amp;authorid=15123057491121882332&amp;authuser=2&amp;user=1xyTLLUAAAAJ">Google Scholar</a></div> http://jims-a.org/index.php/jimsa/article/view/1006 Application of Jaccard Distance Measure for IVIF MCDM Problems 2021-12-10T15:47:07+00:00 Anusha Vulimiri anushavulimiri@gmail.com Sireesha Veeramachaneni vsirisha80@gmail.com This paper proposes an approach to solve Multiple Criteria Decision-making (MCDM) problems when the data given by expert is Interval-Valued Intuitionistic Fuzzy (IVIF) information. A decision-making model is constructed by using the distance measure: Normalized Jaccard distance measure. The robustness of the model is illustrated and validated through numerical example. Further, the problem of choosing best e-learning tool in higher education is considered as a case study. 2021-12-02T00:00:00+00:00 Copyright (c) 2021 Journal of the Indonesian Mathematical Society http://jims-a.org/index.php/jimsa/article/view/1018 Analysis of Forest Carrying Capacity on Eos histrio in North Sulawesi 2021-12-10T15:47:07+00:00 Nastitie Nastitie aku.nastitie@gmail.com Gantina Rachmaputri gantina.r@math.itb.ac.id The International Union for the Conservation of Nature and Natural Resource (IUCN) Red List found that there are currently over 8.000 critically endangered species and the number seems likely to rise in the future. One of the species included in the IUCN Red List is Eos histrio, also known as the Red-and-blue lory, a bird endemic to Indonesia that inhabits Nusa Utara Islands, North Sulawesi. It lives in a forest with tall trees as its natural habitat. According to the Central Bureau of Statistics (BPS), the forest area is decreasing every year and has caused the bird to lose their habitats and its population is declining. IUCN also reported that there are 8.230 – 21.400 Eos histrio in 1999, however in 2016, it was only around 5.500 – 14.000. Its population will be declining due to extensive deforestation and poor conservation. Using Pontryagin maximum principle, this study found that one of the methods to protect the Eos histrio population is by reducing deforestation in North Sulawesi by at least 10% where the population of the bird could increase within a year. 2021-12-02T00:00:00+00:00 Copyright (c) 2021 Journal of the Indonesian Mathematical Society http://jims-a.org/index.php/jimsa/article/view/1030 On Birkhoff Angles in Normed Spaces 2021-12-10T15:47:07+00:00 Hendra Gunawan hgunawan@math.itb.ac.id Muhamad Jamaludin mjamaludin@students.itb.ac.id Mas Daffa Pratamadirdja pratamadirdja@students.itb.ac.id <p>Associated to Birkhoff orthogonality, we study Birkhoff angles in a normed space and present some of their basic properties. We also discuss how to decide whether an angle is more acute or more obtuse than another. In addition, given two vectors $x$ and $y$ in a normed space, we study the formula for Birkhoff `cosine' of the angle from $x$ to $y$ from which we can, in principal, compute the angle. Some examples will be presented.</p> 2021-12-02T00:00:00+00:00 Copyright (c) 2021 Journal of the Indonesian Mathematical Society http://jims-a.org/index.php/jimsa/article/view/1043 Connectivity Indices of Coprime Graph of Generalized Quarternion Group 2021-12-10T15:47:07+00:00 Siti Zahidah siti.zahidah@fst.unair.ac.id Dwi Mifta Mahanani mdwimifta@ub.ac.id Karine Lutfiah Oktaviana karine.lutfiah.oktaviana-2018@fst.unair.ac.id <p>Generalized quarternion group (Q_(4n)) is a group of order $4n$ that is generated by two elements x and y with the properties x^{2n}=y^4=e and xy=yx^{-1}. The coprime graph of Q_{4n}, denoted by Omega_{Q_{4n}}, is a graph with the vertices are elements of Q_{4n} and the edges are generated by two elements that have coprime order. The first result of this paper presented that Omega_{Q_{4n}} is a tripartite graph for n is odd and Omega_{Q_{4n}} is a star graph for n is even. The second one presented the connectivity indices of Omega_{Q_{4n}}. Connectivity indices of a graph is a research area in mathematics that popularly applied in chemistry. There are six indices that are presented in this paper, those are first Zagreb index, second Zagreb index, Wiener index, hyper-Wiener index, Harary index, and Szeged index.</p>Generalized quaternion group (Q4n) is a group of order 4n that is generated by two elements x and y with the properties x 2n = y 4 = e and xy = yx−1 . The coprime graph of Q4n, denoted by ΩQ4n , is a graph with the vertices are elements of Q4n and the edges are formed by two elements that have coprime order. The first result of this paper presents that ΩQ4n is a tripartite graph for n is an odd prime and ΩQ4n is a star graph for n is a power of 2. The second one presents the connectivity indices of ΩQ4n . Connectivity indices of a graph is a research area in mathematics that popularly applied in chemistry. There are six indices that are presented in this paper, those are first Zagreb index, second Zagreb index, Wiener index, hyper-Wiener index, Harary index, and Szeged index. 2021-12-02T00:00:00+00:00 Copyright (c) 2021 Journal of the Indonesian Mathematical Society http://jims-a.org/index.php/jimsa/article/view/989 Gourava and Hyper-Gourava Indices of Some Cactus Chains 2021-12-10T15:54:37+00:00 Basavanagoud B. b.basavanagoud@gmail.com Shruti Policepatil shrutipatil300@gmail.com The mathematical chemistry deals with applications of graph theory to study the physicochemical properties of molecules theoretically. A topological index of a graph is a numeric quantity obtained from the graph mathematically. A cactus graph is a connected graph in which no edges lie in more than one cycle. In this paper, we compute Gourava and hyper-Gourava indices of some cactus chains. 2021-12-10T00:00:00+00:00 Copyright (c) 2021 Journal of the Indonesian Mathematical Society