Judul: Sifat-sifat panas tembakau (Nicotiana tabacum) rajangan
Abstrak: Tujuan penelitian ini adalah menetukan sifat-sifat panas tembakau (Nicotiana tabacum). Sifat-sifat panas yang ditentukan yaitu panas laten penguapan, difusifitas dan konduktifitas panas. panas Bahan yang digunakan dalam penelitian ini adalah tembakau rajangan Temanggung. Penentuan panas laten penguapan dilakukan secara tidak langsung yaitu dengan menentukan persamaan kadar air keseimbangannya. Kadar air keseimbangan tembakau rajangan diperoleh dari hasil percobaan Samsuri (1990). Sedangkan difusifitas panas diukur dengan alat pengukur difusifitas yang dikembangkan oleh Dickerson (1965). Dan konduktifitas panas diukur dengan metode "Fitch" dan "Probe". Persamaan panas laten penguapan tembakau rajangan bagian bawah berdasarkan model persamaan kadar air keseimbangan Henderson dan adalah: Chung-Pfost berturut-turut...
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Judul: Pengukuran panas jenis, konduktivitas panas buah bengkuang (Pachyrhyzus aerosus) dalam rangka penentuan nilai difusivitas panas
Abstrak: Salah satu aspek yang dapat meningkatkan peranan tanaman hortikultura adalah dengan meningkatkan produksi buah-buahan. rusak. Pada umumnya buah-buahan sifatnya mudah Untuk mengawetkan produksi buah-buahan tersebut dapat dilakukan dengan pendinginan. Dengan pendinginan kesegaran, aroma, tekstur dan nilai gizi dari komoditi masih dapat dipertahankan (Jordan, R.C. dan G.B. Priester, 1965). Pendinginan selalu berkaitan dengan masalah pindah panas, sehingga untuk mengetahui masalah-masalah pindah panas tersebut, perlu penelitian mengenai sifat thermal bahan yang didinginkan. Tujuan dari penelitian ini adalah (1) Menentukan nilai panas jenis (Cp) buah Bengkuang dengan kalorimeter yang dibuat sendiri. (2) Menentukan nilai konduktivitas panas (K) dan difusivitas panas (a) buah Bengkuang. Metode yang digunakan untuk menentukan panas jenis Bengkuang dan Beras dalam penelitian ini adalah metode campuran (method of mixtures), yaitu digunakan persamaan keseimbangan panas antara bahan dan sistem kalorimeter, dimana panas yang diberikan oleh bahan sama dengan panas yang diterima oleh sistem kalorimeter. ..dst
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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