Judul: Kajian stabilitas beberapa formulasi bir pletok (minuman khas Betawi) dan pengaruhnya selama penyimpanan
Abstrak: Bir pletok merupakan salah satu minuman tradisional yang berasal dari daerah Betawi. Minuman ini pada hakikatnya adalah jamu, tetapi memiliki rasa yang manis. Minuman ini berkhasiat menurunkan gejala masuk angin, mengatasi sariawan, kelelahan dan reumatik. Pemasaran bir pletok saat ini masih mengalami masalah, yaitu umur simpannya yang relatif singkat, sehingga belum diproduksi dalam jumlah yang besar. Penelitian ini bertujuan untuk mendapatkan formulasi minuman bir pletok yang disukai dengan umur simpan yang lebih baik dari sebelumnya serta untuk mempelajari stabilitas beberapa formulasi yang dibuat berdasarkan pada peningkatan penggunaan rempah-rempah yang mengandung komponen antimikroba dan mengetahui pengaruhnya selama penyimpanan. Penelitian ini secara umum terbagi dalam dua tahap, yaitu penelitian pendahuluan dan penelitian lanjutan. Penelitian pendahuluan meliputi penyiapan bahan baku, pengukuran kadar air, pembuatan formula bir pletok dan pengujian organoleptik. Penelitian lanjutan meliputi penyimpanan bir pletok dalam botol pada dua tingkat suhu, yaitu suhu kamar (29-30°C) dan suhu 37°C. Selama delapan minggu penyimpanan tersebut dilakukan pengamatan terhadap nilai pH, nilai total padatan terlarut, derajat kecerahan, total mikroba dan uji organoleptik terhadap aroma dan warna bir pletok. Bir pletok terbuat dari 17 macam rempah, yaitu jahe, kayu secang, cabe jawa, kayu manis, sereh, lada putih, lada hitam, daun pandan, cengkeh, kembang pala, biji pala, adas manis, kapulaga besar, kapulaga kecil, jintan hitam, pekak dan kayu mesoyi. Formula yang diujikan terdiri dari empat macam, yaitu formula standar (formula 1), formula 2 dengan peningkatan kayu secang 50 persen, formula 3 dengan peningkatan kayu manis sebesar 50 persen dan formula 4 dengan peningkatan cengkeh sebesar 50 persen. Kandungan gula dan rempah yang digunakan untuk keempat formula bir pletok adalah 12% (w/v) gula dan 1,00% (w/v) campuran rempah. ...
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Judul: Pengaruh Suhu dan Transparansi Kemasan terhadap Stabilitas Kapasitas Antioksidan sebagai Parameter Umur Simpan Bir Pletok
Abstrak: Bir Pletok is a Betawi traditional beverage product made from spices and herbs. Bir Pletok has many advantages, such as to keep body warm and to prevent cold . Bir pletok’s key benefit is related to its antioxidant capacity. The packaging and the storage environment are two important factors in the beverage industry include bir pletok. These factors could affect the antioxidant capacity. The antioxidant capacity in food could decrease due to high temperature and other specific conditions. In the present study the change of antioxidant capacity during the storage and the storage time of bir pletok in the bottle glass packaging with different transperancy and different storage temperature were evaluated. ASS method was used to find the storage time of bir pletok with temperature parameter and ESS method was used to find the storage time of bir pletok with packaging transperancy parameter , whereas the reduction of DPPH method was used to determine the antioxidant capacity of bir pletok during 8 weeks of storage. The storage time of bir pletok that had been storage in 300, 370C, and 500C were 29,45 days, 22,55 days, and 10,67 days respectively. Among the three levels of storage temperatures evaluated in this research, the best temperature for bir pletok storage is 300C. The storage time of bir pletok that had been storage in transparent, brown, and dark bottle glass were 19,28 days, 25,05 days, and 29,91 days respectively. The result of the study showed that the non-transparent packaging was the best condition for bir pletok storage.
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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