Judul: Potential and Hazard Management of Citumang Tourism Area, Pangandaran Regency
Abstrak: Potensi bahaya yang terdapat di kawasan wisata Citumang terdapat tiga jenis yaitu potensi bahaya fisik, biologi dan aktivitas manusia. Pengambilan data potensi bahaya ini dilakukan pada bulan Agustus tahun 2020. Penelitian ini dilakukan dengan menggunakan jenis data primer dan sekunder. Analisis potensi bahaya di kawasan wisata Citumang dianalisis menggunakan penilaian risiko menurut UNEP 2008 untuk bahaya fisik dan biologi dan NPSA 2008 untuk penilaian bahaya aktivitas manusia. Potensi bahaya fisik yang terdapat di Citumang memiliki tingkat risiko sedang dan rendah. Potensi bahaya biologi di Citumang mempunyai nilai risiko rendah dan potensi bahaya aktivitas manusia mempunyai nilai yang rendah. Hasil penilaian risiko dari setiap aspek ini ditangani dengan pilihan manajemen pengurangan risiko karena manajemen risiko ini dibuat untuk mengevaluasi setiap risiko yang terjadi di kawasan wisata Citumang., There are three types of potential hazards in the Citumang tourism area, the potential is a physical, biological and human activity. This research was conducted in August 2020 using a primary dan secondary data type. Data analysis of potential hazards in the Citumang tourism area use a risk assessment according to UNEP 2008 for physical and biological hazards and NPSA 2008 for hazard assessment of human activities. The potential physical hazards contained in Citumang have a low medium level of risk. Potential biological hazards in Citumang have a low risk and the potential hazards of human activities have a low value. The result of risk assessment from each aspect are handled with risk reduction management option because risk management is designed to evaluate every risk that occursin the Citumang tourism area.
Keyword: Kawasan wisata Citumang, manajemen bahaya, potensi bahaya, Citumang tourism area, risk management, hazard potential

Judul: Identifikasi Potensi Bahaya Bagi Keselamatan Pengunjung di Kawasan Wisata Pantai Pangandaran, Kabupaten Ciamis, Jawa Barat.
Abstrak: Kawasan Wisata Pantai Pangandaran merupakan salah satu satu tempat yang menjadi Obyek Wisata Unggulan Provinsi Jawa Barat. Sebagai obyek wisata unggulan, banyak sekali pengunjung yang datang ke kawasan tersebut, namun pada periode tertentu seringkali terjadi kecelakaan pengunjung. Penelitian ini bertujuan untuk mengidentifikasi potensi bahaya bagi keselamatan pengunjung di Kawasan Wisata Pantai Pangandaran yang meliputi potensi bahaya fisik dan biologi untuk bahan pertimbangan bagi manajemen keselamatan pengunjung di kawasan tersebut. Penelitian dilakukan pada tiga lokasi pantai, yaitu Pantai Barat, Pantai Timur, dan Pantai Pasir Putih. Penelitian dilaksanakan pada bulan Juni hingga Juli 2011. Penelitian dilakukan terhadap potensi bahaya fisik dan biologi yang terdapat di kawasan. Pengumpulan data dilakukan dengan cara observasi lapang, wawancara kepada responden pengunjung, masyarakat, dan penjaga pantai, serta studi literatur. Responden pengunjung ditentukan secara purposive sampling, sedangkan responden masyarakat ditentukan secara convinient sampling. Jumlah responden pengunjung dan masyarakat masing-masing sebanyak 100 responden ditentukan dengan menggunakan rumus Slovin. Hasil penelitian menunjukkan bahwa potensi bahaya fisik di Kawasan Wisata Pantai Pangandaran terdiri dari arus rip, ombak tukik, tsunami, gempa bumi, gelombang, dan pasang surut, sedangkan potensi bahaya biologi yang terdiri dari ubur-ubur, monyet ekor panjang, ular laut, bulu babi, ikan lepu ayam, dan ikan lepu batu. Berdasarkan hasil penilaian resiko didapat bahwa arus rip termasuk dalam potensi bahaya dengan tingkat resiko bahaya besar (substantial risk), sehingga manajemen pengurangan resiko potensi bahaya yang dapat dilakukan yaitu dengan cara menghindari resiko. Bentuk aplikasi menghindari resiko yaitu tidak memperbolehkan pengunjung berenang pada kawasan zona arus rip, kemudian teknis manajemen keselamatan pengunjung untuk potensi bahaya arus rip tersebut yaitu dengan cara mensosialisasikan teknik-teknik menyelamatkan diri saat terbawa arus rip.
Keyword: Identification, hazard, risk, visitor, safety

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