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<![CDATA[A Staggered Grid Numerical Method for the Navier-Stokes Equation ]]>
<![CDATA[Sudi Mungkasi]]>
<![CDATA[ Journal of Natural A Vol 1, No 2 (2014) ]]>
Publisher : <![CDATA[Fakultas MIPA Universitas Brawijaya ]]>
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<![CDATA[We consider incompressible fluid flows governed by the two-dimensional Navier-Stokes equation. The Navier-Stokes equation is solved numerically using a staggered grid finite difference method. Our aim in this paper is to assess the performance of this numerical method for the Navier-Stokes equation. The lid-driven cavity problem is taken into account to test the numerical method. In order to achieve our aim we focus on the motion of the fluid, and in particular, its velocity. Our results are compared with some available benchmark data. Keywords— finite difference method, lid-driven cavity flow, Navier-Stokes equation, staggered grid.]]>
<![CDATA[Model Components Selection in Bayesian Model Averaging Using Occam's Window for Microarray Data ]]>
<![CDATA[Ani Budi Astuti]]>;
<![CDATA[Nur Iriawan]]>;
<![CDATA[irhamah Irhamah]]>;
<![CDATA[Heri Kuswanto]]>
<![CDATA[ Journal of Natural A Vol 1, No 2 (2014) ]]>
Publisher : <![CDATA[Fakultas MIPA Universitas Brawijaya ]]>
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<![CDATA[Microarray is an analysis for monitoring gene expression activity simultaneously. Microarray data are generated from microarray experiments having characteristics of very few number of samples where the shape of distribution is very complex and the number of measured variables is very large. Due to this specific characteristics, it requires special method to overcome this. Bayesian Model Averaging (BMA) is a Bayesian solution method that is capable to handle microarray data with a best single model constructed by combining all possible models in which the posterior distribution of all the best models will be averaged. There are several method that can be used to select the model components in Bayesian Model Averaging (BMA). One of the method that can be used is the Occam's Window method. The purpose of this study is to measure the performance of Occam's Window method in the selection of the best model components in the Bayesian Model Averaging (BMA). The data used in this study are some of the gene expression data as a result of microarray experiments used in the study of Sebastiani, Xie and Ramoni in 2006. The results showed that the Occam's Window method can reduce a number of models that may be formed as much as 65.7% so that the formation of a single model with Bayesian Model Averaging method (BMA) only involves the model of 34.3%. Keywords— Bayesian Model Averaging, Microarray Data, Model Components Selection, Occam's Window Method.]]>
<![CDATA[Quartz Crystal Resonator Parameter Calculation Based on Impedance Analyser Measurement Using GRG Nonlinear Solver ]]>
<![CDATA[Setyawan Purnomo Sakti]]>
<![CDATA[ Journal of Natural A Vol 1, No 2 (2014) ]]>
Publisher : <![CDATA[Fakultas MIPA Universitas Brawijaya ]]>
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<![CDATA[Quartz crystal resonator which is used as a basis for quartz crystal microbalance (QCM) sensor was modelled using many different approach. The well-known model was a four parameter model by modelling the resonator as a circuit composed from two capacitors, inductor and resistor. Those four parameters control the impedance and phase again frequency applied to the resonator. Electronically, one can measure the resonator complex impedance again frequency by using an impedance analyser. The resulting data were a set of frequency, real part, imaginary part, impedance value and phase of the resonator at a given frequency. Determination of the four parameters which represent the resonator model is trivial for QCM sensor analysis and application. Based on the model, the parameter value can be approximately calculated by knowing the series and parallel resonance. The values can be calculated by using a least mean square error of the impedance value between model and measured impedance. This work presents an approach to calculate the four parameters basic models. The results show that the parameter value can be calculated using an iterative procedure using a nonlinear optimization method. The iteration was done by keeping two independence parameters R0 and C0 as a constant value complementary. The nonlinear optimization was targeted to get a minimum difference between the calculated impedance and measured impedance.Keywords— QCM Sensor, four parameter model, impedance measurement.]]>
<![CDATA[Relationship Model Anomaly Harvested Rice with a Weighted Rainfall Index in Buru Maluku Using Bootstrap Aggregating MARS Methods to Predict the Forecast Error Rates Harvested Area and Rice Production ]]>
<![CDATA[Kondo Lembang F.]]>;
<![CDATA[Loupatty G.]]>;
<![CDATA[Talakua M. W.]]>
<![CDATA[ Journal of Natural A Vol 1, No 2 (2014) ]]>
Publisher : <![CDATA[Fakultas MIPA Universitas Brawijaya ]]>
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<![CDATA[Seasonal climate variations is one of the main causes of the diversity of crop production in Indonesia. Long drought and drought causing crop failures and food shortages that could affect agricultural production and food security. The indicator is a decline in acreage , harvested area and production declined sharply when climate irregularities. The magnitude of the impact caused by climatic irregularities cause we need a model that connects the harvested area with indicators of climate anomalies that can do the proper planning and anticipation measures early in order to avoid the risk of crop failure. Buru as the largest rice -producing areas in the provinces of Maluku course is expected to avoid the risk of crop failure in order not to disrupt the supply of rice. Data Collection and forecast rice production annually conducted by the Central Statistics Agency (BPS). BPS forecast model but has not entered a climatic factor, while the climate affect rice production. This research used the bootstrap aggregating MARS method to model anomaly rice harvested area with a weighted rainfall index to predict the error rate forecast harvested area and rice production. From the analysis using the best models of replication bagging MARS 150 times in the first period (January-April) and 200 times in second period (May-August) and third period (September-December) obtained an error rate forecast harvested area and rice production respectively by 5.72% and 6.81%.Keywords— Anomaly Area harvested, weighted rainfall index, MARS, Boostrap Aggregating, rice production.]]>
<![CDATA[A Variational Approach of Creeping Solitons with Hartman-Grobman Theorem in Complex Ginzburg-Landau Equation ]]>
<![CDATA[Nur Izzati Khairudin]]>;
<![CDATA[Farah Aini Abdullah]]>;
<![CDATA[Yahya Abu Hassan]]>;
<![CDATA[Agus Suryanto]]>
<![CDATA[ Journal of Natural A Vol 1, No 2 (2014) ]]>
Publisher : <![CDATA[Fakultas MIPA Universitas Brawijaya ]]>
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<![CDATA[The behavior of quintic nonlinear dispersion coefficient of creeping soliton in a spatial domain with hyperbolicity analysis of Hartman-Grobman Theorem by using variational approach is studied. Complex Ginzburg-Landau equation (CGLE) is used in the analysis as we relate the creeping soliton with Hartman- Grobman Theorem. We evaluated our work based on perturbed Jacobian matrix from system of three supercritical ordinary differential Euler-Lagrange equations, in which the eigenvalues of the stability matrix touch the imaginary axis. As a consequence in unfolding the bifurcation of creeping solitons, the equilibrium structure ultimately chaotic at the variation of the coefficient µ away from the critical value, µc . This leads to hyperbolicity loss of Hartman-Grobman Theorem in the dissipative system driven out the oscillatory instability of µ exceeded the criticality parameter corresponding to the Hopf bifurcations as the system is highly complex. This overall approach restrict to numerical investigation of the space time hyperbolic variation of CGLE.Keywords— Dissipative solitons, complex Ginzburg-Landau equation.]]>
<![CDATA[Effect of Energy Gain and Loss in Breathing Pattern of Solitary Wave for Nonlinear Equation ]]>
<![CDATA[Nur Shafika Abel Razali]]>;
<![CDATA[Farah Aini Abdullah]]>;
<![CDATA[Yahya Abu Hasan]]>;
<![CDATA[Agus Suryanto]]>
<![CDATA[ Journal of Natural A Vol 1, No 2 (2014) ]]>
Publisher : <![CDATA[Fakultas MIPA Universitas Brawijaya ]]>
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<![CDATA[Nonlinear phenomena like soliton propagate over long distance in transmit information, without dispersion energy due to the properties of the solitons, which has balanced of the nonlinearity effect and dispersion effect resulted the signal undistorted and symmetric bell shape curve. We study about the properties and breathing pattern of solitary wave of pulses in absence and present of energy loss, by using one dimensional nonlinear equation; cubic-quintic complex Ginzburg-Landau equation (cqCGLE). Breathing pattern of soliton behaviour is constructed with hyperbolic sine and hyperbolic tangent as initial amplitude profile and observed by means of numerical simulation. Resulting in observation of breathing pattern of soliton in term of energy loss and gain while travelling, but it still maintains spatial localization of wave energy in the changing pulses shape through a unique dissipative soliton.Keywords— Soliton, nonlinearity, dispersion, breathing, energy.]]>
<![CDATA[Search Engine of Subject Using Error Correction Lavenshtein (Case Study Digital Documents of Al Qu'ran and Hadith) ]]>
<![CDATA[Edy Santoso]]>;
<![CDATA[marji Marji]]>;
<![CDATA[Nurul Hidayat]]>
<![CDATA[ Journal of Natural A Vol 1, No 2 (2014) ]]>
Publisher : <![CDATA[Fakultas MIPA Universitas Brawijaya ]]>
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<![CDATA[Qur'an and Hadith is the holy book for Muslims as a way of life in everyday life. Qur'an itself consists of 30 juz, 114 letters and approximately 6,666 verses. While the Hadith is also very much making it difficult for Muslims who still lay preacher or a legal basis for the search for subjects interrelated among the verses in the Qur'an and Qur'anic verses linkages and Hadith. Today, existing search engines (Icon Find) but did not do a grouping of words that have been found so that the reader is difficult to understand because the scattered pages of documents. On the other hand people tend to have typing errors to look for a particular subject and if an error occurs writing the words that contain a particular subject was not found. Clerical errors are generally caused by the proximity of the keyboard layout, less adept at using finger, or because the two characters are located confused. Levenshtein algorithm is an algorithm that is reliable and can be used to calculate the relationship between the strings by way of calculating the distance or amount of difference between two strings. With this method the system is expected to have mistyped the recommendations and improvements to search and classify the subject of the search results in a separate sheet that allows the reader. Based on the experimental results generated that included the greater accuracy that the fewer the number of words recommended.Keywords— Search Engines, Writing Errors, Levenshtein algorithm, The Qur'an and Hadith digital.]]>
<![CDATA[Dynamic Mathematical Model of Urban Spatial Pattern: Mobility vs Externality ]]>
<![CDATA[Rahma Fitriani]]>;
<![CDATA[darmanto Darmanto]]>
<![CDATA[ Journal of Natural A Vol 1, No 2 (2014) ]]>
Publisher : <![CDATA[Fakultas MIPA Universitas Brawijaya ]]>
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<![CDATA[Household’s residential choice of location determines urban spatial pattern (e.g sprawl). The static model which assumes that the choice has been affected by distance to the CBD and location specific externality, fails to capture the evoution of the pattern over time. Therefore this study proposes a dynamic version of the model. It analyses the effects of externalities on the optimal solution of development decision as function of time. It also derives the effect of mobility and externality on the rate of change of development pattern through time. When the increasing rate of utility is not as significant as the increasing rate of income, the externalities will delay the change of urban spatial pattern over time. If the mobility costs increase by large amount relative to the increase of income and inflation rate, then the mobility effect dominates the effects of externalities in delaying the urban expansion.Keywords— dynamic model, externality, mobility, urban spatial pattern.]]>
