Judul: Study on the role of uban forest types toward iar temperature reduction : a case study in Bogor City-West Java
Abstrak: Nowadays, quality of urban environment is challenging problem. Urban development indicated by the increase of population as well as development in all aspects, it is not only give positive impacts but also negative impacts and ultimately, it can impact the degradation of environment quality. This fact is indicated by environment problems in urban area, for instance: air pollution which reduces oxygen supply and overwhelms production of Carbon dioxide (COz), also air temperature rising.
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Judul: Dampak Dinamika Perubahan Tutupan Lahan Terhadap Suhu Udara di Kota dan Kabupaten Bogor
Abstrak: Perkembangan suatu kota yang sangat pesat mengakibatkan terjadinya perubahan dalam penggunaan lahan, yang mengakibatkan banyaknya perubahan pada lahan non terbangun beralih menjadi lahan terbangun seperti pembangunan infrastruktur fisik yang pesat dan tidak terencana membuat berkurangnya sebaran vegetasi. Penelitian ini bertujuan mengidentifikasi perubahan tutupan lahan dan dampaknya terhadap suhu udara di Kota Bogor dan Kabupaten Bogor. Perubahan tutupan lahan di Kota Bogor didominasi perubahan lahan vegetasi pohon berkurang berkisar 16,99% menjadi menjadi lahan bervegetasi campuran bertambah menjadi 7,04% dan lahan terbangun bertambah 10,6%, sementara kelas badan air mengalami penurunan hanya 0,65%. Dampak dari perubahan tutupan lahan terhadap suhu udara di Kabupaten Bogor masih lebih rendah dibandingkan Kota Bogor, karena tutupan lahan yang didominasi vegetasi pohon dan non pohon masih banyak ditemukan dan tidak memiliki perubahan yang signifikan jika dibandingkan dengan Kota Bogor yang memiliki jumlah tutupan lahan terbangun yang luas jika dibandingkan dengan vegetasi pohon dan non pohon., The very rapid development of a city results in changes in land use, which results in many changes in non-built land turning into built-up land such as the rapid and unplanned development of physical infrastructure that reduces the distribution of vegetation. This study aims to identify changes in land cover and their impact on temperature. air in the Bogor City and Regency of Bogor. Changes in land cover in Bogor City were dominated by land changes, tree vegetation decreased by 16.99% to mixed vegetation, increased to 7.04% and built-up land increased by 10.6%, while the class of water bodies decreased by only 0.65%. The impact of land cover changes in Regency of Bogor is still lower than Bogor City, because land cover dominated by tree and non-tree vegetation is still widely found and does not have significant changes when compared to Bogor City which has a large amount of built-up land cover compared to tree and non-tree vegetation.
Keyword: air temperature, change, land cover

Judul: The Construction of Greedy SVP LLL Algorithm
Abstrak: A lattice is a set of all integer linear combination of a set of linearly independent vectors in ℝ𝑛���. The independent vectors are called bases of lattice. Any lattice can be generated from many bases, and these bases have the same cardinality. In the lattice, the most fundamental and renowned problem is the Shortest Vector Problem (SVP). SVP is a tracking problem of the shortest nonzero vector in a lattice with equivalent bases. In two dimensions, SVP problem has resolved exactly by Gauss’ algorithm. When the lattice dimension is higher than two, A.K. Lenstra, H.W. Lenstra and L. Lovasz gave a LLL algorithm to compute approximation of nonzero shortest vector in the lattice. Reduced bases solution obtained from LLL algorithm still be an approximation and has polynomial running time of arbitrary dimension which large enough. In 1994, Schnoor and Euchner modified this LLL algorithm as a new variant which later was named deep insertion LLL algorithm. This algorithm is a modified version of the LLL algorithm to the terms of the exchange step to improve the accuracy of output of LLL reduced bases and applying it to the subset sum problem. The purpose of this research are: (1) Reconstruct the LLL algorithm and deep insertion LLL algorithm using a geometric approach. (2) Construct a greedy SVP LLL algorithm. (3) Implement the three algorithms in a symbolic programming language, and evaluate them experimentally. A bases ℬ=[𝐛���1,𝐛���2,…,𝐛���𝑛���] in ℝ𝑚��� is called reduced LLL with parameter 𝛿��� if satisfies: (a) |𝜇���𝑗���𝑖���|≤12, for every integer 𝑖���,𝑗��� with 1≤𝑖���<𝑗���<𝑛���. (b)𝛿���‖𝜋���𝑗���(𝐛���𝑗���)‖2≤‖𝜋���𝑗���(𝐛���𝑗���+1)‖2, for 𝑗���=1,2,…,𝑛���−1,where 𝛿��� is a reduced parameter of real numbers with 14<𝛿���<1. The first requirement is the reduced basis 𝛿��� must “nearly orthogonal” and in its computation case, this requirement can be reached out by using the Gram-Schmidt’s orthogonalization. While the second requirement is called exchange step, or used to called as Lovasz condition. By using both of these requirements, then they establish the LLL algorithm. Then, Schnoor and Euchner modify the LLL algorithm based on the requirements of the exchange step called the deep insertion LLL algorithm, where the exchange step is based on the comparison of the projected vector in orthogonal complement [𝐛���1,𝐛���2,…,𝐛���𝑘���−1]⊥ after j-th reduction. To construct greedy SVP LLL algorithm, the requirements of the exchange step is based on purely by comparing norm of lattice 𝐛���𝑗��� with norm lattice 𝐛���𝑖��� for 𝑖���=1,2,3…,𝑗���−1. The process of insertion reduced vector after the exchange step also has done greedily. Then, we calculate the number of arithmetic operation in greedy SVP LLL algorithm for further analysis. The result of our exprimentation for three algorithms on the certain matrix size shows that the running time of the three algorithms increases propotional to the size of the matrix. The result also shows that by using 𝛿���=34 for the LLL algorithm and the deep insertion LLL algorithm, and the greedy SVP LLL algorithm which is a new variant made by using no parameter of 𝛿���, outperform of the other of two previous algorithm in terms of speed with the same output.
Keyword: LLL algorithm, LLL deep insertion algorithm, greedy SVP LLL algorithm