Judul: Isolasi dan penapisan bakteri dari permukaan buah untuk mempertahankan kesegaran pascapanen cabai merah (Capsicum annuum cv. Hot Beauty)
Abstrak: Cabai merah merupakan komoditas yang penting di Indonesia. Karena cabai merah cepat mengalami kebusukan, maka perlu dicari cara pengawetan yang alami sehingga kebugaran pascapanen cabai merah dapat dipertahankan selama beberapa hari. Pengawetan secara alami dapat dilakukan menggunakan mikroorganisme lain yang dapat berperan sebagai agens kontrol biologi terhadap serangan cendawan patogen. Selain itu, mikroorganisme tertentu dapat mempengaruhi fisiologi pascapanen cabai merah. Agens kontrol biologi (antagonis) alami dapat diperoleh dari permukaan buah yang merupakan habitat alami bakteri. Setelah dilakukan isolasi bakteri dari permukaan buah kedondong, sawo, srikaya, pisang kepok, tomat, dan belimbing, diperoleh 39 isolat terpilih. Selanjutnya dilakukan penapisan bertahap terhadap isolat-isolat tersebut sampai diperoleh 3 isolat terbaik, yaitu isolat K37, Sw02, dan B16. Isolat K37 mampu meminimalkan timbulnya bercak pada cabai merah sedangkan isolat B16 mampu mengurangi penurunan bobot yang terjadi. Isolat Sw02 tampaknya merupakan isolat yang paling berpotensi untuk mengurangi banyaknya bercak yang disebabkan oleh serangan cendawan Colletotrichum capsici dan mempertahankan kebugaran tekstu r cabai merah sampai 3 hari setelah panen. Ketiga isolat ini merupakan bakteri Gram negatif, bentuk selny a batang dengan morfologi koloni yang beragam.
Keyword: Cabai merah

Judul: Penapisan dan Identifikasi Bakteri Endofit Cabai Merah Penghambat Colletotrichum capsici.
Abstrak: Cabai merah menjadi salah satu komoditas pertanian penting yang dibudidayakan di Indonesia. Adanya kenaikan maupun penurunan produksi cabai merah yang fluktuatif disebabkan oleh patogen Colletotrichum sp. Salah satu agen biokontrol untuk mengatasi masalah tersebut adalah penggunaan bakteri endofit. Bakteri endofit yang mampu memproduksi Asam Indol Asetat (AIA) dapat meningkatkan pertahanan tanaman terhadap patogen. Penelitian ini bertujuan mengisolasi, mengarakterisasi, dan mengidentifikasi isolat bakteri endofit tanaman cabai merah yang memiliki aktivitas sebagai penghasil AIA yang mampu menghambat patogen Colletotrichum capsici. Sebanyak 109 isolat bakteri endofit asal BB Biogen dan Hama Proteksi Tanaman IPB telah dianalisis. Isolat dengan kode B6.2 merupakan isolat yang dapat menghambat C. capsici tertinggi yaitu 75% dan isolat dengan kode A27 mampu menghasilkan AIA tertinggi yaitu 70.41 ppm. Pengujian ke-8 isolat bakteri endofit menunjukkan 3 isolat bakteri endofit potensial, yaitu A4.2, B6.2, dan D11.1. Berdasarkan hasil sekuensing gen 16S rRNA diketahui isolat A4.2 termasuk dalam genus Pseudomonas serta isolat B6.2 dan D11.1 termasuk dalam genus Bacillus.
Keyword: bakteri endofit, produksi AIA, patogen Colletotrichum capsici

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