Indonesia Conference Directory

Corresponding Author
Mokhammad Ridwan Yudhanegara

Institutions
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Abstract
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Keywords
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Topic
Applied Mathematics

Link: https://ifory.id/abstract/rugz37t6ZnjK

Corresponding Author
MOH IVAN AZIS

Institutions
Hasanuddin University

Abstract
A boundary element method (BEM) is utilized to find numerical solutions to boundary value problems of quadratically graded media governed by a spatially varying coefficients anisotropic-diffusion convection-reaction equation. The variable coefficients equation is firstly transformed into a constant coefficients equation for which a boundary integral equation can be formulated. A BEM is then derived from the boundary integral equation. Some problems are considered. A FORTRAN script is developed for the computation of the solutions. The numerical solutions verify the validity of the analysis used to derive the boundary element method with accurate and consistent solutions. The computation shows that the BEM procedure elapses very efficient time in producing the solutions. In addition, results obtained for the considered examples show the effect of anisotropy and inhomogeneity of the media on the solutions. An example of a layered material is presented as an illustration of the application.

Keywords
Boundary element method; Diffusion-convection-reaction; Anisotropic inhomogeneous media; Incompressible flow

Topic
Applied Mathematics

Link: https://ifory.id/abstract/Urhtw6aVf2mT

Corresponding Author
Fadli Azis

Institutions
a) Magister of Mathematical and Natural Science Padjadjaran University
* fadliazis16[at]gmail.com
b) Department of Mathematical and Science Padjadjaran University

Abstract
In this paper proposes an EOQ mathematical model for deteriorating items during the inventory process. The model is developed with exponentially decreasing demand, constant deterioration, and allowing for shortages. The time-varying holding cost is a linear function of time. The ordering cost, the holding cost, the deteriorating cost, and the shortage cost are considered in the inventory management. A numerical example is presented to illustrate the model and the sesitivity analysis of various parameters is carried out.

Keywords
Inventory, EOQ, deterioration, exponential declining demand, shortage

Topic
Applied Mathematics

Link: https://ifory.id/abstract/9rnmHjNCc3dZ

Corresponding Author
Lisana Sumarah Pratignyo

Institutions
a)Magister of Mathematical and Natural Science Padjadjaran University
*lisana_sp[at]yahoo.com
b)Departement of Mathematical and Science Padjadjaran University

Abstract
This research was carried out at the Faculty of Science and Technology at the Islamic University of As Syafiiyah. There were problems that occured, some lecturers worked in companies or in offices with sufficient time which made it difficult to determine the right lecture schedule according to the willingness when teaching lecturers. Lecturers schedules that change and the process of making class schedules that are still manual results in taking a long time and difficulty managing scheduling. This study aims to optimize the suitability of teaching and learning activities with lecture scheduling which takes place with the Simulated Annealing method. This optimization methode scheduling uses Simulated Annealing, data collection methodes with field studies are interviews and observations, literatur studies and the like and with software using the Matlab program. The results of study can make it easy for administrators to process and arrange schedulling lecturers that are appropiate for the lecturers willingness to help the scheduling process better and not take long time.

Keywords
Simulated Annealing; Optimization; Scheduling; Matlab

Topic
Applied Mathematics

Link: https://ifory.id/abstract/AJwERjgukep6

Corresponding Author
Muhammad Faudzi Bahari

Institutions
a) Master program in Mathematics, Faculty of Mathematics and Natural Sciences, Universitas Padjadjaran, INDONESIA
*mfaudzibahari[at]gmail.com
b) Department of Mathematics, Faculty of Mathematics and Natural Sciences, Universitas Padjadjaran, INDONESIA

Abstract
This study discusses a method for flowshop scheduling on 3-machines with n jobs. The purpose of this study is to minimize the cost of leasing machines that must be issued by a company in the production process carried out. The several things considered are the existence of the job-block criteria in the production scheduling process.

Keywords
Flowshop, Minimize Rental Cost

Topic
Applied Mathematics

Link: https://ifory.id/abstract/LWp8Fm4YtXqA

Corresponding Author
Endang Rusyaman

Institutions
Department of Mathematics Universitas Padjadjaran, Bandung, Indonesia

Abstract
Fractional differential equation is an ordinary differential equation in which the order is fractional number. It can be said that fractional differential equation is a generalization of an ordinary differential equation where the order is natural number. In this paper, a fractional differential equation with the order α and β, where α and β are rational numbers, is introduced. Solution of this differential equation is found by using Laplace transformation and presented in the form the Mittag-Leffler function. Graph of solutions function are then described by using the Matlab software.

Keywords
Differential equations, Fractional order, Laplace Transform, Mittag-Leffler

Topic
Applied Mathematics

Link: https://ifory.id/abstract/V8PJjwYKgRu9

Corresponding Author
Erwin Harahap

Institutions
a) Department of Mathematics, Universitas Islam Bandung
Jalan Tamansari No. 1 Bandung 40116, Indonesia.

b) Department of Statistics, Universitas Islam Bandung
Jalan Tamansari No. 1 Bandung 40116, Indonesia.

Abstract
Traffic is a very vital medium for various means of land transportation that connects various locations and even large cities. The smooth traffic of a city is one of the performance parameters of the local government. Furthermore, the smooth traffic determines the great development of economic, social, educational and technology. As the increasing level of civilization development and also the population, traffic becomes more congested and becomes a big problem that is very difficult to avoid. In this study, we proposed a traffic simulator system LINTAS-BD 1.2, or commonly called as "LINTAS" which served as a tool to solve traffic congestion problems. Various methods and traffic engineering designs can be simulated first through the LINTAS system, before they are actually implemented on the road. The benefit of the LINTAS is to evaluate and simulate traffic conditions based on the design of a particular method or traffic engineering. Furthermore, through simulations, it can be known and tested analytically about the level of accuracy, efficiency, and effectiveness of the method and design. Through the simulation, the most appropriate traffic management method can be found, so that the problem of traffic congestion can be solved. The model and the design system of LINTAS is the arrangement and integration of various blocks or modules included: roads, traffic light, arrival of vehicles, queues, servers, and various obstacles such as intersections, terminals, markets, branches, etc. These various blocks are then combined into a single unit application as a simulator. The objective of this research is to compile a simulation application (traffic simulator) that can be used as a tool to accurately predict traffic situations, and as a medium for testing traffic engineering. The LINTAS simulator is created using the SimEvents toolbox and runs on the MATLAB-Simulink software. The LINTAS system is compiled based on Mathematics, specifically the Queueing Theory.

Keywords
traffic, congestion, simulation, queuing networks, simevents-matlab

Topic
Applied Mathematics

Link: https://ifory.id/abstract/DUuP84k26rJ3

Corresponding Author
Luthfi Hakim

Institutions
Universitas Islam Majapahit

Abstract
New results in the form of velocity distribution in the square duct elbow 90-degree have been obtained from the simulation results. The flow characteristics through which are analyzed using commercial CFD software. The Reynolds averaged Navier Stokes (RANS) equation will be solved numerically using the finite difference method and using the SIMPLE algorithm. The test model to be used in this study is square duct which is installed in the inlet section 90-degre elbow with a double damper placed at a distance offrac{x}{D_{h}}=2 after out late elbow. In this paper, the effect of the damper opening angle on the velocity profile on the 90-degree square duct is simulated in simulation at the opening angle of 30-degree clockwise direction and 30-degree counter-clockwise direction. The simulation results in the form of velocity profile distribution in each position are shown through the graph and obtained a maximum velocity magnitude value of 26.143 m/s which is exactly the place of the damper.

Keywords
Double damper, velocity profile, square duct

Topic
Applied Mathematics

Link: https://ifory.id/abstract/GAcNZzbLx2ad

Corresponding Author
MOH IVAN AZIS

Institutions
Hasanuddin University

Abstract
A boundary element method is utilized to find numerical solutions to boundary value problems of trigonometrically graded media governed by a spatially varying coefficients anisotropic-diffusion convection equation. The variable coefficients equation is firstly transformed into a constant coefficients equation for which a boundary integral equation can be formulated. A boundary element method (BEM) is then derived from the boundary integral equation. Some problems are considered. The numerical solutions justify the validity of the analysis used to derive the boundary element method with accurate and consistent solutions. A FORTRAN script is developed for the computation of the solutions. The computation shows that the BEM procedure elapses very efficient time in producing the solutions. In addition, results obtained from the considered examples show the effect of the anisotropy of the media on the solutions. An example of a layered material is presented as an illustration of the application.

Keywords
Boundary element method; Steady anisotropic-diffusion convection equation; Trigonometrically graded media; Incompressible flow

Topic
Applied Mathematics

Link: https://ifory.id/abstract/PZRAu4w3xpah

Corresponding Author
Faryad Ali

Institutions
Al-Imam Mohammad Ibn Saud Islamic University (IMSIU),
Riyadh 11623,
Kingdom of Saudi Arabia

Abstract
The projective special orthogonal group $PSO^+_8( 3) cong O^+_8(3).2_1$ is a group obtained from the special orthogonal group $SO_8(3)$ on factoring by the group of scalar matrices it contains. The group $PSO^+_8( 3)$ has a maximal subgroup of the form $2^6{cdot}S_8$ with index $3838185$. The group $ar{Q}cong 2^6{cdot}S_8$ is a non-split group extension of an elemenrary abelian $2$-group of order $64$ by the symmetric group $S_8$. In the present article, we construct the non-split extension $ar{Q}$ and compute its character table by using the Fischer-Clifford matrices.

Keywords
Fischer matrices; Non-split extension; Character table

Topic
Applied Mathematics

Link: https://ifory.id/abstract/u4ZyLqYG7bDr

Corresponding Author
Rika Amelia

Institutions
a) Master Program in Mathematics, Faculty of Mathematics and Natural Sciences, Universitas Padjadjaran, INDONESIA
*rika17003[at]mail.unpad.ac.id
b) Department of Mathematics, Faculty of Mathematics and Natural Sciences, Universitas Padjadjaran, INDONESIA

Abstract
One of the main obstacles in crop cultivation is the occurrence of fungal infections. Fungal spores can spread due to direct contact between susceptible hosts and infected hosts, which can be controlled using botanical fungicides. We constructed a mathematical model of the growth of logistics on the spread of plant diseases. From this model, we show the value of the Basic Reproduction Number (R0) of plant diseases transmission. The value of R0 is obtained by finding the largest eigenvalue of the next generation matrix. The results obtained show that when R0 is greater than one (R0>1), the endemic equilibrium point will be stable. However, if R0 is less than one (R0<1), the endemic equilibrium point is unstable. In addition, the results of this discussion indicate that by using botanical fungicides can reduce the infected host population. We provide numerical simulations to describe the results of the analysis obtained.

Keywords
Basic Reproduction Number; Local Stability Analysis; Optimal Control

Topic
Applied Mathematics

Link: https://ifory.id/abstract/RJNaQbHnjVmv

Corresponding Author
Tri Susilawati

Institutions
a) Department of Civil Engineering, Sumbawa University of Technology
jalan Raya Olat Maras Kecamatan Moyo Hulu Kabupaten Sumbawa 84314, Indonesia
*tri.susilawati[at]uts.ac.id
b) Department of Agro Industrial Technology, Sumbawa University of Technologi
*mikhratunnisa[at]uts.ac.id

Abstract
The utilization of land in Sumbawa District to produce corn will effect cutting trees new land fields It-s not paddi field . It has effect on environment. Those such as lack of water in ground, flood, and soon. Henceforth this research aim at making optimation model cutting tree for new land could enhance the productivity of corn and making appropriate model to optimalize of farmets benefit by using simplex methode. Based on simplex counting, it-s needed 21.618 and 77.873 Ha paddy field and non paddy field to plant corn in order to increase corn harvest. To boost farner-s benefit, they harvest 672609 tonas follows, 434.001 ton of corn by 15% of water content, 46.182 ton of corn by 20% of water content and 192.426 ton of corn by 25% of water content.

Keywords
Simplex Method, Optimization, Corn

Topic
Applied Mathematics

Link: https://ifory.id/abstract/8BJmEew9WTkA

Corresponding Author
Kalfin Kalfin

Institutions
a) Master Program in Mathematics, Faculty of Mathematics and Natural Sciences, Universitas Padjadjaran, Jl. Raya Bandung-Sumedang Km 21, Jatinangor 45363, Sumedang. West Java, INDONESIA
*kalfin17001[at]mail.unpad.ac.id
b) Department of Mathematics, Faculty of Mathematics and Natural Sciences, Universitas Padjadjaran, Jl. Raya Bandung-Sumedang Km 21, Jatinangor 45363, Sumedang. West Java, INDONESIA

Abstract
Investing in mining stocks, investors are often faced with risk problems. Usually to minimize risk, this is done by forming an investment portfolio. This paper aims to discuss the optimization of the investment portfolio. The data analyzed are several mining stocks traded on the capital market in Indonesia. Optimization is done by using the mean-absolute deviation model to determine the optimal weight. Where optimization is done using a singular covariance matrix. Based on the results of optimization, we can obtain a weight allocation composition that provides an optimal portfolio. In addition, we also predict the amount of return on expectations and risks in the optimal portfolio formed. So that the composition of this optimal weight can be used as a consideration for investors in investing their capital in several analyzed mining stocks.

Keywords
Mining stocks, return, portfolio, optimization, mean-absolute deviation

Topic
Applied Mathematics

Link: https://ifory.id/abstract/r3WuLFpqfdcb

Corresponding Author
Ramdhan Fazrianto Suwarman

Institutions
Suryakancana University
ramdhan[at]unsur.ac.id

Abstract
Real options are one of the most fascinating research topics in Finance today, since 1977 Stewart C. Myers from the MIT Sloan School of Management published his pioneering article on this subject in the Journal of Financial Economics. Real options are techniques for support capital budgeting decisions which adapting the techniques developed for financial security options. The purpose of using this real option is to capture options contained in projects that cannot be captured by discounted cash flow models that operate as a basic framework for almost all financial analyzes. The real option valuation process will be complemented by interest rate stochastic modeling and volatility stochastic modeling to further capture flexibility and volatility from the existing economic and financial situation. The valuation will be using Monte Carlo simulation with Matlab programming language on crude oil data from the North Sea oil field. The data is obtained from Charlie Grafström and Leo Lundquists thesis with the title "Real Options Valuation vs. DCF Evaluation - An application to a North Sea oilfield ".

Keywords
Real Options, Stochastic Interest Rate, Stochastic Volatility, Monte Carlo Simulations

Topic
Applied Mathematics

Link: https://ifory.id/abstract/HexbMh4qjXwT

Corresponding Author
Rustam -

Institutions
a) Industrial and Financial Mathematics Research Group, Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung, Indonesia
*rustam_math06[at]s.itb.ac.id
b) Food and Biomass Processing Technology Research Group, Faculty of Industrial Technology, Institut Teknologi Bandung, Indonesia

Abstract
Indonesia is the second largest biodiversity country in the world. Indonesia has a variety of top agricultural and plantation commodities, whereas each commodity has premium products which are normally related to its specific character/flavour and are generally associated with the producing origins. Specific character/flavour is represented by composition of metabolites each origin. To find out the specific character/flavour found in various Indonesian plantation commodities, clustering is needed. In this paper, we perform clustering on one Indonesian plantation commodity based on their metabolites composition. Metabolite compositions of samples of several origins of the commodity are clustered using the Hard C-Means algorithm with the Xie-Beni index as the cluster validity. Our present results confirm that each origin has a unique characteristic and belongs to a separate cluster.

Keywords
Indonesian plantation commodity; Clustering; Hard C-Means; Xie-Beni index

Topic
Applied Mathematics

Link: https://ifory.id/abstract/Hb3WaZcYNKqE

Corresponding Author
Farid Badruzzaman

Institutions
(a) Mathematics Department, Universitas Islam Bandung
Jalan Ranggamalela No. 1, Bandung 40116, Indonesia

(b) Dept. of Computer System Engineering, Universitas Tanjungpura
Jalan Jenderal Ahmad Yani, Pontianak 78115, Indonesia.

Abstract
The production process is the main problem in the production of raw materials into finished materials. The delay in settlement time will result in additional time and costs. In order to anticipate this situation, one of solution is to use network analysis. Network analysis described that the network must be run which is limited by time. The purpose of this study is to find out the network in a logical sequence, the right time to settle, and the opportunity to complete the production process of childrens Hijab, especially at the ABC Store Bandung Indonesia. The method used in this analysis is the PERT method. PERT is an analytical method designed to help in scheduling activities that must be carried out in a certain order.

Keywords
production process, veil, PERT method

Topic
Applied Mathematics

Link: https://ifory.id/abstract/6fdEP72RcXFh