Judul: Analisis Faktor-Faktor yang Memengaruhi Risiko Produksi Jambu Air di Kecamatan demak Kabupaten Demak
Abstrak: Kecamatan Demak adalah salah satu penghasil jambu air terbesar di Kabupaten Demak, namun produksi jambu air di Kecamatan Demak berfluktuasi, menandakan terjadinya risiko produksi. Tujuan dari penelitian ini adalah untuk menganalisis pengaruh faktor-faktor produksi terhadap risiko produksi jambu air yang dihadapi petani di Kecamatan Demak. Jumlah sampel yang digunakan dalam penelitian ini ada 40 responden. Metode yang digunakan dalam penentuan sampel adalah proportional random sampling. Penelitian ini menggunakan model Just dan Pope sebagai metode analisis data. Hasil penelitian ini menunjukkan bahwa peningkatan jumlah penggunaan pupuk dapat meningkatkan produksi jambu air secara nyata, peningkatan jumlah penggunaan pestisida dan tenaga kerja dapat meningkatkan risiko produksi secara nyata (risk inducing factor) dan peningkatan penggunaan pupuk dapat mengurangi risiko produksi jambu air secara nyata (risk reducing factor).
Keyword: jambu air, model Just and Pope, risiko produksi

Judul: The Correlation between Entrepreneur Characteristics and Water Apple Farming Performance in Demak District, Demak Regency
Abstrak: Kecamatan Demak merupakan salah satu sentra penghasil jambu air di Kabupaten Demak. Produktivitas jambu air di Kecamatan Demak mengalami fluktuasi selama beberapa tahun terakhir. Karakteristik wirausaha pada petani jambu air diduga menjadi salah satu faktor terjadinya flutuasi pada produktivitas jambu air di Kecamatan Demak. Tujuan penelitian ini adalah menganalisis hubungan karakteristik wirausaha dan kinerja usahatani jambu air di Kecamatan Demak. Penentuan sampel pada penelitian ini menggunakan teknik purposive sampling dan snowball sampling dengan jumlah 40 petani jambu air. Alat analisis yang digunakan dalam penelitian ini adalah Rank Spearman. Karakteristik wirausaha yang diteliti pada penelitian ini adalah percaya diri, inovatif, tanggung jawab, berani mengambil risiko, dan kerja keras. Pengukuran kinerja usahatani pada penelitian ini menggunakan indikator hasil produksi dan pendapatan. Hasil analisis menunjukkan bahwa kelima karakteristik wirausaha berkorelasi secara signifikan dengan kinerja usaha. Hal ini berati ketika karakteristik wirausaha petani jambu air meningkat maka kinerja usahatani akan meningkat.
Keyword: entrepreneur characteristics, farming performance, water apple, water apple farmer 

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