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Journal of Mathematical and Fundamental Sciences
Published by Institut Teknologi Bandung
ISSN : 23375760     EISSN : 23385510     DOI : https://doi.org/10.5614/j.math.fund.sci.
Core Subject : Science, Education,
Astronomy Chemistry Earth & Planetary Sciences Mathematics Physics
Journal of Mathematical and Fundamental Sciences welcomes full research articles in the area of Mathematics and Natural Sciences from the following subject areas: Astronomy, Chemistry, Earth Sciences (Geodesy, Geology, Geophysics, Oceanography, Meteorology), Life Sciences (Agriculture, Biochemistry, Biology, Health, Medical, Pharmacy), Mathematics, Physics, and Statistics.
Arjuna Subject : Matematika - Matematika (Lain-Lain)
Articles 689 Documents
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A Mathematical Model of Black Rhino Translocation Strategy Dipo Aldila; Ashleigh Jane Hutchinson; Matthew Woolway; Norman Owen-Smith; Edy Soewono
Journal of Mathematical and Fundamental Sciences Vol. 47 No. 1 (2015)
Publisher : Institute for Research and Community Services (LPPM) ITB

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/j.math.fund.sci.2015.47.1.8

Abstract

A deterministic mathematical model of the black rhino population in South Africa will be discussed. The model is constructed by dividing the black rhino population into multiple patches. The impact of human intervention on different translocation strategies is incorporated into the model. It is shown that, when implemented correctly, translocation can accelerate the growth rate of the total black rhino population. Equilibrium points are shown with their local stability criteria.
Anomalous ULF Emissions and Their Possible Association with the Strong Earthquakes in Sumatra, Indonesia, during 2007-2012 Suaidi Ahadi; Nanang Tyasbudi Puspito; Gunawan Ibrahim; Sarmoko Saroso; Kiyohumi Yumoto; M. Muzli
Journal of Mathematical and Fundamental Sciences Vol. 47 No. 1 (2015)
Publisher : Institute for Research and Community Services (LPPM) ITB

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/j.math.fund.sci.2015.47.1.7

Abstract

Eleven strong Sumatran earthquakes, with their epicenter less than 550 km away from the Kototabang (KTB) geomagnetic station (2007-2012), were studied to examine the occurrence of anomalous ultra-low frequency emissions (ULF-EM). Anomalous ULF signals, possibly associated with the earthquake's precursors, were determined by the Welch ratio SZ/SH at 0.06 Hz at the KTB station. These ULF anomalies were then compared with geomagnetic data observed from two reference stations in Darwin and Davao, to prevent misinterpretation of global geomagnetic disturbances as precursors. This study aims to analyze the relationship between earthquake magnitude and hypocenter radius, and seismic index against lead time during ULF-EM anomalies. We used the polarization ratio Welch method in terms of power spectrum density to evaluate the geomagnetic data by overlapping windows and applying fast Fourier transform (FFT). The results showed anomalous variations in onset and lead time, determined using the standard deviation controlling the SZ/SH power pattern. Our positive correlation between lead time of ULF emission and earthquake magnitude as well as between lead time and seismic index. It shows a negative correlation between hypocenter distances to KTB station against lead time.
Modified Convective Stratiform Technique (CSTm) Performance on Rainfall Estimation in Indonesia E. Endarwin; Safwan Hadi; Bayong Tjasyono HK; Dodo Gunawan; S. Siswanto
Journal of Mathematical and Fundamental Sciences Vol. 46 No. 3 (2014)
Publisher : Institute for Research and Community Services (LPPM) ITB

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/j.math.fund.sci.2014.46.3.4

Abstract

This study has analyzed a rainfall estimation using a modified convective stratiform technique (CSTm). Unlike the original convective stratiform technique (CST), which only utilizes infrared (IR) data, CSTm applies not only IR data but also passive microwave (PMW) data. Two major modifications contained in CSTm are: (1) the application of a variability index (VI) method that uses PMW data to perform convective and stratiform separation,and (2) the ability to determine the average extensive coverage of the new areas of each pixel point as a result of the utilization of the PMW data. In this study, rainfall estimation was conducted for 23 points spread over four major islands in Indonesia. The estimation was performed based only on IR and PMW data obtained from coincident observations. For verification, the estimation results were compared with real observations. The main verification action conducted in this study used multi-category contingency tables for four categories and this action was supported by the root mean square error (RMSE)method.The verification results of the hourly estimation conducted for 4 days in early November 2011 showed that CSTm can effectively improve the performance quality of CST.
Dynamical Model for Transmission of West Nile Virus in Chicken-Mosquito Interaction Jafaruddin Hamid; Juni Wijayanti Puspita; Nuning Nuraini; Edy Soewono
Journal of Mathematical and Fundamental Sciences Vol. 46 No. 3 (2014)
Publisher : Institute for Research and Community Services (LPPM) ITB

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/j.math.fund.sci.2014.46.3.7

Abstract

The West Nile virus (WNV) is transmitted through the bites of infected mosquitoes. The spread of WNV in chicken populations is quite unique. Although chickens can contract the virus through a mosquito bite, they immediately build immunity to the virus and do not show physical symptoms of illness and hence chickens are only temporary carriers of the virus. Recently, experimental results have shown that mosquitoes do not change fecundity behavior, yet results indicate that resistance to infection is associated with afitness cost in terms of mosquito survival. We constructed a host-vector type transmission model for WNV in mosquito-chicken populations. The basicreproductive ratio, Ro , was obtained. From sensitivity analysis of Ro it was shown that under certain conditions this ratio decrease "“ with an increase of the lifetime of mosquito infection.
Multifractal Characterization of Pore Size Distributions of Peat Soil Joko Sampurno; Azrul Azwar; Fourier Dzar Eljabbar Latief; Wahyu Srigutomo
Journal of Mathematical and Fundamental Sciences Vol. 48 No. 2 (2016)
Publisher : Institute for Research and Community Services (LPPM) ITB

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/j.math.fund.sci.2016.48.2.2

Abstract

This paper discusses a multifractal analysis of the microscopic structure of peat soil. The aim of this study was to apply the multifractal technique to analyze the properties of five slices of peat soil (L1-L5). Binary images (220 x 220 pixels, with a conversion value of 9.41 μm/pixel) were made from the thin slices and then analyzed. This analysis was conducted to obtain the relationship between physical parameters and complexity parameters. The results showed that the spectrum of f(α) can describe well the pore size distribution and average size of pores correlated with the value of D(0). A high value of the average pore size is followed by a low D value and vice versa.
Study on Heat Island Effect Induced by Land Use Change Increased Temperature in Metropolitan Jakarta Sopia Lestari; Setyo S. Moersidik; Fadli Syamsudin
Journal of Mathematical and Fundamental Sciences Vol. 47 No. 2 (2015)
Publisher : Institute for Research and Community Services (LPPM) ITB

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/j.math.fund.sci.2015.47.2.2

Abstract

The heat island (HI) effect in metropolitan Jakarta was studied using air temperature measurements at 9 meteorological stations in Jakarta, Tanjung Priok, Serang, Halim, Cengkareng, Pondok Betung, Curug, Bogor, Citeko during 1986-2008 and Serpong during 2008-2011 and 2013; land use for forest, industry, water, settlement, open/cleared land in 1997, 2004, 2009, 2012; and total number of industries and total number of vehicles during 1986-2011. Harmonic analysis was used to remove the seasonal component from the temperature time series data, which was filtered with the 30-day moving average technique to capture trends whose significance was tested with the Mann-Kendall method. The results show that industry was a major factor in land use change over Jakarta with an increasing growth/year of 502 ha (9.76%) concentrated in the eastern part of Jakarta from 1997 to 2012. Industry had a spatial cover change similar to deforestation and open/cleared land expansion, especially in Jakarta from 2009 to 2012: 38.8%/year (industry), 8.3%/year(deforestation), and 13.8%/year (open/cleared land). The HI effect increased the temperature trend rate/year in Jakarta, Tanjung Priok, Serang, Halim, Pondok Betung, Cengkareng, Curug, and Bogor about 0.051°C, 0.021°C, 0.018°C, 0.012°C, 0.006°C, 0.006°C, 0.005°C, and 0.004°C from 1986 to 2008, respectively, equivalent to average warming in the city, suburban, and mountainous areas of around 2.5°C, 0.6°C, and 0.4°C, respectively within 100 years from 2009.
QuEChERS Method for the Determination of Pesticide Residues in Indonesian Green Coffee Beans using Liquid Chromatography Tandem Mass Spectrometry Harmoko Harmoko; Rahmana Emran Kartasasmita; Astika Tresnawati
Journal of Mathematical and Fundamental Sciences Vol. 47 No. 3 (2015)
Publisher : Institute for Research and Community Services (LPPM) ITB

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/j.math.fund.sci.2015.47.3.7

Abstract

A method using QuEChERS sample preparation followed by liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESIMS/MS) was developed for quantitative determination of 14 pesticide residues in Indonesian green coffee beans. The European Standard Method EN 15662:2008 was modified to obtain an appropriate extraction and clean-up procedure for green coffee bean samples. Homogenous slurry samples were extracted with 1% acetic acid in acetonitrile and the extracts were cleaned up by a high pigment dispersive SPE. LC-ESI-MS/MS was operated in the MRM mode for two specific precursor-product ion transitions per target compound to obtain 4 identification points. Representative matrix-matched calibration curves were applied to compensate matrix effects. This method was validated according to the requirements of SANCO/12495/2011. Limits of detection (LODs) and limits of quantification (LOQs) were obtained in the ranges of 0.2-2.9 μg kg-1 and 0.8-9.7 μg kg-1 respectively, showing lower values than the maximum residu limits (MRLs) set by importing countries. The method was applied to determine 14 pesticide residues in 181 Indonesian green coffee bean samples that were taken from different regions. Some pesticide residues were found in these samples and detected to be higher than the MRLs.
Optimal Vaccination and Treatment Schedules in a Deterministic Avian influenza Model Nuning Nuraini; Tasmi Tasmi
Journal of Mathematical and Fundamental Sciences Vol. 48 No. 2 (2016)
Publisher : Institute for Research and Community Services (LPPM) ITB

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/j.math.fund.sci.2016.48.2.7

Abstract

In this study, a transmission model of the Avian influenza disease was developed and analyzedin view of optimization of vaccination and medical treatment. The model is a host-vector model. We focussed on control of Avian influenza, where a vaccination is given to susceptible poultry, while medical treatment is given to infected humans. In the model, the human population is divided into four compartments: susceptible humans, infected humans, recovered humans, and treated humans. Meanwhile, the poultry population is divided into three compartments: susceptible poultry, infected poultry, and vaccinated poultry. To analyze the dynamical behavior of the model, we obtained the disease-free equilibrium, the endemic equilibrium, and the basic reproduction ratio.Furthermore, a model of the optimal vaccination and medical treatment schedule was constructed to know the optimal strategy for controlling Avian influenza. The model can be used to determine the minimal cost of controlling the disease. The model is solved by a genetic algorithm method. Numerical simulations showed that effective control of Avian influenza can be achieved with a combination of vaccination and medical treatment. Likewise, the optimal schedule and strategy for controlling Avian influenza are shown.
Some Problems on the Making of Mathematical Modelling of a Profit-Loss Sharing Scheme Using Data Simulation Novriana Sumarti; Kuntjoro Adji Sidarto; Muhammad Syamsuddin; Vina Fitriyani Mardiyyah; Abu Rizal
Journal of Mathematical and Fundamental Sciences Vol. 47 No. 1 (2015)
Publisher : Institute for Research and Community Services (LPPM) ITB

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/j.math.fund.sci.2015.47.1.1

Abstract

The mathematical model for a profit-loss sharing scheme is formulated in order to see how this scheme can replace the traditional practice of lending money against high interest by usurers. It is sourced from the musyarakah method in Islamic Syariah law and implemented for small-scale investments of traditional-market traders. They are the common target of usurers, so they may end up poorer than they were before. The main goal of the model is to find the appropriate portion of profit share, so the investment is profitable not only for the investor but also for the trader. There are three main problems in the process of formulating the mathematical model and finding optimized results. The first problem is providing the appropriate amount of data to be implemented in the model. The second problem is determining the objective function for the optimization of the portion of profit share. The last problem is determining the appropriate values of the parameters for certain types of traders. We found a significant result in determining the appropriate values of the parameters that explain the potential capability of the traders in handling larger amounts of capital to be invested in order to achieve our main goal.
Estimation of S-wave Velocity Structures by Using Microtremor Array Measurements for Subsurface Modeling in Jakarta Mohamad Ridwan; A. Afnimar; Sri Widiyantoro; Masyhur Irsyam; Hiroaki Yamanaka
Journal of Mathematical and Fundamental Sciences Vol. 46 No. 3 (2014)
Publisher : Institute for Research and Community Services (LPPM) ITB

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/j.math.fund.sci.2014.46.3.9

Abstract

Jakarta  is located on  a  thick sedimentary  layer that  potentially has a very  high  seismic  wave  amplification.  However,  the  available information concerning the  subsurface model and bedrock depth  is insufficient  for a seismic hazard  analysis.  In  this  study,  a  microtremor  array  method  was  applied  to estimate the geometry and S-wave velocity of the sedimentary layer. The spatial autocorrelation  (SPAC)  method  was  applied  to  estimate  the  dispersion  curve, while  the S-wave  velocity  was  estimated  using  a  genetic  algorithm  approach. The  analysis  of  the  1D  and  2D  S-wave  velocity  profiles  shows  that  along  a north-south  line,  the  sedimentary  layer  is  thicker  towards  the  north.  It  has  a positive  correlation  with  a  geological  cross section  derived  from  a borehole down to  a depth of  about 300 m. The SPT data from  the  BMKG site  were used to  verify  the  1D  S-wave  velocity  profile.  They  show  a  good agreement. The microtremor analysis  reached  the engineering bedrock  in a  range from 359  to 608  m  as  depicted by a  cross section  in  the  north-south  direction. The site class was also estimated at each site, based on the average S-wave velocity until 30 m depth. The sites UI to ISTN belong to class  D (medium soil),  while BMKG and ANCL belong to class E (soft soil).

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