Judul: Tipologi Mangrove dan Keterkaitannya dengan Kondisi Lingkungan di Desa Karangsong Indramayu
Abstrak: Mangrove is defined one of the vegetation types in tidal areas. This research was conducted to find out the typology of mangrove and the relationship with environmental condition in Karangsong village. The observations result showed that mangrove vegetation in Karangsong consisted of Api Api (A. marina) and Bakau (R. marina). Density of mangrove consist of tree stage (35.67-0.5 ind/100m2), sapling stage (0-34.67 ind/100m2) and seed stage (0-31 ind/m2) for each species. A. marina is more adaptive due to a high value of mangrove density and INP. Environment condition of Karangsong still in growth optimal range of mangrove. Based on the fact, it is recommendated to plant dan do rehabilitation.
Keyword: 

Judul: nstitutional Analysis Of Mangrove Rehabilitation in Karangsong Indramayu West Java
Abstrak: Kawasan pesisir Desa Karangsong mengalami kerusakan akibat abrasi yang dipicu oleh konversi hutan mangrove menjadi kawasan tambak yang terjadi sejak tahun 1960-an. Kondisis pesisir Karangsong tanpa hutan mangrove pada akhirnya mengakibatkan kerusakan tanggul tambak akibat abrasi dan penurunan hasil produksi budidaya serta hasil tangkapan ikan dan udang di sekitar pesisir akibat daya dukung lahan yang semakin menurun, sehingga menjadi dampak buruk yang dirasakan oleh masyarakat sekitar. Upaya pemulihan kawasan pesisir melalui aksi bersama rehabilitasi mangrove yang dilakukan oleh Kelompok Pantai Lestari sejak Tahun 2008, telah berhasil membentuk kembali hutan mangrove di pesisir Desa Karangsong yang kemudian dikelola dan dijadikan lokasi ekowisata. Manfaat ekologi maupun ekonomi dapat dirasakan baik oleh pengelola maupun masyarakat sekitar. Penelitian ini dilaksanakan di Desa Karangsong Kecamatan Indramayu Kabupaten Indramayu Jawa Barat. Tujuan dari penelitian ini adalah untuk menganalisis faktor-faktor pendorong terbentuknya aksi bersama rehabilitasi kawasan mangrove Karangsong, menganalisis perubahan hak kepemilikan, menganalisis aktor dan tata kelola/kelembagaan kawasan mangrove, serta menganalisis biaya transaksi dalam menerapkan kelembagaan berkelanjutan. Pengumpulan data dilakukan melalui wawancara terhadap key informan dan survey terhadap responden yang dipilih secara purposive. Metode analisis yang digunakan adalah analisis deskriptif kualitatif melalui analisis property rights, analisis stakeholder, content analysis, dan analisis biaya transaksi. Hasil penelitian menunjukkan bahwa faktor pendorong Kelompok Pantai Lestari melakukan aksi bersama dalam rehabilitasi mangrove Karangsong berasal dari faktor eksternal dan internal. Dari faktor eksternal yaitu adanya kerusakan pesisir Karangsong dan dukungan dari stakeholders lain serta dari faktor internal yaitu penurunan penghasilan, penyelamatan asset, willingness to invest serta pengetahuan dan pengalaman berorganisasi para pendiri Kelompok Pantai Lestari. Perubahan hak kepemilikan telah terjadi pada kawasan mangrove yang direhabilitasi dari open access menjadi group/communal property. Kejelasan status lahan menjadi salah satu faktor keberhasilan rehabilitasi mangrove. Kelompok Pantai Lestari yang didukung oleh pemerintah Desa Karagsong, Diskanla dan Pertamina menjadi aktor kunci dalam upaya pemulihan kondisi mangrove di pesisir Karangsong. Desain kelembagaan yang berkelanjutan menitikberatkan pada peningkatan dalam sinergitas dan koordinasi antar stakeholders serta keterlibatan masyarakat setempat melalui pemberdayaan. Estimasi biaya transaksi yang dibutuhkan untuk dapat menerapkan kelembagaaan pengelolaan kawasan mangrove berkelanjutan di Karangsong adalah sebesar Rp. 516.426.000,- per tahun yang digunakan untuk pembiayaan kegiatan sosialisasi, koordinasi, pemberdayaan masyarakat dan pengawasan kawasan., The coastal area of Karangsong Village was damaged due to abrasion triggered by the conversion of mangrove forests into pond areas that occurred since the 1960s. Coastal without mangrove forest eventually resulted in damage to pond embankments due to abrasion as well as decline in cultivation yields due to the decreasing carrying capacity of the land. The decline of fish and shrimp catches around the coast became the bad impact felt by the fishermen. Efforts to restore coastal areas through collective action of mangrove rehabilitation conducted by Kelompok Pantai Lestari since 2008 have succeeded in reshaping mangrove forest in coastal Karangsong village which then managed and used as location of ecotourism. Ecological and economic benefits are gained both by the managers and the surrounding community. This research was conducted in Karangsong Village, Indramayu District, Indramayu Regency, West Java. The purposes of this research are to analyze the factors driving collective action of rehabilitation of Karangsong mangrove area, to
Keyword: collective action, institutional design, mangrove area, property rights, stakeholders pemangku kepentingan, Rehabilitasi Mangrove, Pengelolaan Mangrove, Mangrove Pesisir, Mangrove berkelanjutan

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