Judul: Finding solution for Magic Square as Linear Equation System (LES) Problems
Abstrak: Magic square adalah suatu susunan bilangan dari 1 sampai 𝑛2 ke dalam kotak-kotak sebanyak n × n sedemikian sehingga jumlah dari tiap kolom, baris, dan diagonalnya sama. Magic square telah dipelajari sejak abad 20 SM dalam sebuah buku catatan dari China bernama Lo Shu. Magic square mulai dipakai dan diartikan dalam berbagai cara hingga dibahas dan dipelajari secara ilmiah sejak tahun 1300. Magic square secara khusus dipelajari dalam tulisan ilmiah ini sebagai sebuah permasalahan Sistem Persamaan Linear (SPL). Solusi dari magic square akan dicari mulai dari magic square berukuran 1 × 1 sampai dengan 5 × 5. Pencarian solusi dilakukan dengan penyederhanaan SPL interpretasi dari magic square oleh operasi baris dasar pada matriks koefisiennya. Dengan bantuan software Mathematica 7.0 pada proses komputasinya, didapatkan seluruh solusi untuk kelima ukuran magic square. Operasi-operasi matriks juga akan digunakan untuk mendapatkan magic square baru dari yang sudah ada. Hasil yang didapatkan kemudian digunakan untuk mencari adanya pola ataupun algoritma yang dapat dibentuk untuk dipakai dalam mencari solusi secara umum.
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Judul: Penyelesaian Puzzle Sudoku Menggunakan Pemrograman Linear Integer
Abstrak: Sudoku can be viewed as a puzzle in mathematics. Players must fill in a n2 × n2 matrix which is containing some given enteries, so that each row, column, and n × n mini grid contains each integer 1 through n2. The objectives of this research are to study the traditional Sudoku puzzle, Sudoku X puzzle (diagonal Sudoku) and use branch and bound method, to find the relation between the number of possible solution with the size of sudoku, and the number quantity givens. The solutions are determined using branch and bound method that was implemented on m-file script. We can find the relation between the number of possible solution with the size of sudoku, and the number quantity givens. On the other hand, we can not find such relation for general size of sudoku and general configuration
Keyword: Bogor Agricultural University (IPB), branch and bound, linear integer, Sudoku

Judul: Thermal Characteristics and Dynamics of Tropical Cyclone over Western North Pacific Ocean: A Case Study of Typhoon Songda (Chedeng) 2011
Abstrak: The frequent occasion of Tropical Cyclone (TC) over Western North Pacific (WNP) Ocean lies from 10˚N to 26˚N and 121˚E to 170˚E. Sources of TC development come from warm ocean temperature where latent heat is released during condensation processes and subsequently concentrated in the boundary layer. Relative humidity at 850-700 hPa is responsible to produce the most intense storm. Meanwhile, weak vertical wind shear between 850-200 hPa is one of the dynamical factors that lead to the development of TC. Pressure level of 850-200 hPa is chosen to minimize the thermodynamic effect in the lower troposphere. Typhoon Songda (Chedeng in the Philippines) or TSC lasted from May 18th to 30th, 2011 and strengthened into powerful Super Typhoon stage between May 24th and 27th. Long curving track and the exhibition of all sequences of TC life cycle, TSC is then considered as an ideal case of TC. The objective of the study with case of TSC is to investigate the role of thermal characteristics and dynamics on TC intensity. The research is carried out by using Advanced Research of Weather Research and Forecasting model (WRF ARW model) version 3.3. Two domains are employed in the model. The first domain situate from 02˚N to 40˚N and 118˚E to 149˚E and cover spatial resolution () of 33.1 km. The second domain situate from 09˚N to 27˚N and 119˚E to 132˚E with of 11 km. Timestep of the model () is 120 seconds. The model is supported by the following physical parameterization, i.e., Yonsei University Scheme (YSU) in the boundary layer, Kain-Fritsch scheme (KF) in the cumulus, and WRF Single-Moment 3-class scheme in the microphysics. Initial meteorological condition prior to the formation of the cyclone is generated using WRF ARW standard-release model. Sensitivity of the model output is obtained from a selected single-parameter change scenarios, namely, 10 % to 20 % decrease and increase of wind shear initial data at 850-200 hPa, and by 10 % to 20 % decrease of relative humidity initial data at 850-700 hPa. The result showed that the negative correlations between wind shear and intensity are found in wind shear scenarios. Wind shears of 10 ms-1 which lead to strengthening of the wind intensity in the early period of Typhoon development are found in wind shear scenarios. The effect of wind shear changes on wind intensity is statistically significant in the 20 % wind shear scenarios. During mature stage, weak wind intensity occurred when wind shear increase as given in the WRF standard-release and the 20 % decreasing scenario. Different situation is found in the 20 % increasing scenario where wind shear tend to weak and lead to strong wind intensity at this stage. Meanwhile, the reduction of moisture supply at 850-700 hPa resulting from 20 % decreasing relative humidity play a major role in the weakening of wind intensity and reduces mechanical energy of the cycle process as much as 300 J kg-1.
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