Journal of Mathematical and Fundamental Sciences
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Restarting from Specific Points to Cure Breakdown in Lanczos-type Algorithms
Get PDFBreakdown in Lanczos-type algorithms is a common phenomenon which is due to the non-existence of some orthogonal polynomials. It causes thesolution process to halt. It is, therefore, important to deal with it to improve the resilience of the algorithms and increase their usability. In this paper, we consider restarting from a number of different approximate solutions that seem to be attractive starting points. They are: (a) the last iterate preceding breakdown, (b) the iterate with minimum residual norm found so far, and (c) the approximate solution whose entries are the median values of entries of all iterates generated by the Lanczos-type algorithm considered. Although it has been shown theoretically in the context of Arnoldi-type algorithms as well as Lanczos-type algorithms that restarting mitigates breakdown and allows the iterative process to continue and converge to good solutions, here we give an alternative theorem to that effect and a proof of it. However, emphasis is on the quality of the restarting points. Numerical results are included
Simple and Low-Cost On-Package Sticker Sensor based on Litmus Paper for Real-Time Monitoring of Beef Freshness
Get PDFA simple sticker sensor has been constructed using litmus paper and tests have been conducted to detect the freshness of beef samples. The results show that the sticker sensor can be used to determine the degree of beef freshness, since the color change of the litmus paper and the quality degradation of the beef during storage time had a similar trend, where the decay of the beef could be detected clearly (when the red litmus paper changed to blue). The sticker sensor reacted accurately to the beef's freshness in terms of pH change due to beef deterioration from pH 5.61 to 6.24 and from pH 5.67 to 6.02 as shown by its color change in real time at room and chiller temperature respectively. Thus, the sticker sensor can be used as an effective tool for monitoring the microbial quality of packaged fresh meat that correlates with the increased pH of the beef, where the total viable count (TVC) of 5 x 106 cfu/g or 6.698 log cfu/g correlates with a pH of 6.24. These levels were reached at 10 hrs and 7 days at room and chiller temperature respectively. This study provides a foundation for developing a simple sensor for beef freshness
Optimal Control of Isometric Muscle Dynamics
Get PDFWe use an indirect optimal control approach to calculate the optimal neural stimulation needed to obtain measured isometric muscle forces. The neural stimulation of the nerve system is hereby considered to be a control function (input) of the system 'muscle' that solely determines the muscle force (output). We use a well-established muscle model and experimental data of isometric contractions. The model consists of coupled activation and contraction dynamics described by ordinary differential equations. To validate our results, we perform a comparison with commercial optimal control software
A Mathematical Model of Black Rhino Translocation Strategy
Get PDFA 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
Some Problems on the Making of Mathematical Modelling of a Profit-Loss Sharing Scheme Using Data Simulation
Get PDFThe 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
Embryo Incision as a New Technique for Double Seedling Production of Indonesian Elite Coconut Type âKopyorâ
Get PDFOne of the present major limitations of seedling production of kopyor type coconut using embryo culture is that only one seedling can be produced from a single embryo. Therefore, we report on the development of a new breakthrough technique for the production of double seedlings from a single embryo. The technique consists of four steps, viz. (i) germination; (ii) incision; (iii) splitting; and (iv) recovery. A histological study was carried out on the development of the halved embryo into a new shoot. The best recovery process was obtained when the incised embryo was split into two and recovered into Murashige and Skoog (MS) medium supplemented with 2 μM IBA and 15 μM kinetin. Following this protocol, an average of 56 shoots was successfully recovered from 30 zygotic embryos. The histological study also revealed that the meristem tissue of the halved embryo was able to produce a new meristem and primordial leaf. Most of the shoots then went on to produce normal seedlings and could be acclimatized successfully after having developed 2 or 3 leaves. This protocol is useful for routine seedling production of the kopyor-type coconut
Anomalous ULF Emissions and Their Possible Association with the Strong Earthquakes in Sumatra, Indonesia, during 2007-2012
Get PDFEleven 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
Synthesis and Characterization of Bio-based Nanomaterials from Jabon (Anthocephalus cadamba (Roxb.) Miq) Wood Bark: an Organic Waste Material from Community Forest
Get PDFThe application of nanotechnology to produce nanomaterials from renewable bio-based materials, like wood bark, has great potential to benefit the wood processing industry. To support this issue, we investigated the production of bio-based nanomaterials using conventional balls milling. Jabon (Anthocephalus cadamba (Roxb.) Miq) wood bark (JWB), an organic waste material from a community forest was subjected to conventional balls milling for 96 h and was converted into bio-based nanomaterial. The morphology and particle size, chemical components, functional groups and crystallinity of the bio-based nanomaterial were evaluated using scanning electron microscopy (SEM), scanning electron microscopy extended with energy dispersive X-ray spectroscopy (SEM-EDS), Fourier transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD). The particle-sizes obtained for the JWB bio-based nanomaterial were between 43 nm to 469 nm and the functional groups were detected as cellulose. The chemical components found were carbon, oxygen, chloride, potassium and calcium, except for the sample produced from sieve type T14, which did not contain chloride. The crystalline structure was calcium oxalate hydrate (C2CaO4.H2O) with crystalline sizes 21 nm and 15 nm, produced from sieve types T14 and T200 respectively
Study on Heat Island Effect Induced by Land Use Change Increased Temperature in Metropolitan Jakarta
Get PDFThe 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
Molluscan Evidence for Slow Subsidence in the Bobotsari Basin during the Plio-Pleistocene, and Implications for Petroleum Maturity
Get PDFIntegrated studies of the stratigraphy, sedimentology and molluscan paleontology of several late Neogene localities in West and Central Java (Indonesia) showed that deposition took place under marine conditions until early in the Pleistocene in the Bobotsari Basin. In contrast, in the adjacent Bogor and North Serayu basins deposition was terrestrial (fluviatile) during the Pleistocene, as subsidence had ceased. Our interpretation is based mainly on the marine mollusks present in the Plio-Pleistocene Bantardawa-Talanggudang Formation in the Bobotsari Depression. This interpretation is supported by seismic analyses and by age determinations based on planktonic foraminifers. We concluded that slow tectonic subsidence continued in the Bobotsari Depression until the early Pleistocene. Slow, long-continued subsidence in the Bobotsari Basin had a significant impact on hydrocarbon maturity compared to that of adjacent basins. We interpret the high total organic carbon (TOC) in the geochemical analyses of samples from Bobotsari Neogene outcrops as resulting from rapid burial in the Bobotsari Basin and slow subsidence continuing into the early Pleistocene