Judul: Kondisi terumbu karang di perairan kabupaten Sumenep, Madura - Jawa Timur
Abstrak: Informasi mengenai kondisi terumbu karang merupakan langkah awal dalam pengelolaan dan pemanfaatan sumber daya alam yang berguna, khususnya bagi masyarakat Kabupaten Sumenep, Madura-Jawa Timur. Penelitian ini menggunakan data primer dan data sekunder. Data sekunder diambil pada tanggal 01-20 Agustus 2006 di daerah kepulauan kabupaten Sumenep, sedangkan data primer diambil pada tanggal 27 Desember 2007 Noveember 2006 di daerah pesisir kabupaten Sumenep.
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Judul: Kondisi terumbu karang tahun 1998 disekitar P. Kelapa Kep. Seribu Jakarta Utara
Abstrak: Salah satu biota laut didaerah khatulistiwa adalah terumbu karang yang merupakan ekosistem khas laut tropis yang telah banyak memberikan manfaat bagi kelangsungan hidup manusia antara lain dibidang perikanan, wisata bahari, sebagai pelindung pantai, sebagai sumber obat-obatan dan sebagai indikator ekologi. Terumbu karang sebagai tempat hidup dari berbagai biota laut tropis lainnya memiliki keanekaragaman jenis biota yang sangat tinggi dan sangat produktif. Keanekaragaman biota di terumbu karang dengan bentuk dan warna yang beranekaragam menjadikan terumbu karang merupakan panorama di dasar laut yang sangat indah. Sesuai dengan berkembangnya kebutuhan manusia seperti bahan pangan, tempat rekreasi, pelabuhan dan aktivitas lain yang berhubungan dengan laut dan pantai memberikan kontribusi yang cukup besar terhadap kerusakan ekosistem terumbu karang. Hal inilah yang melatar belakangi penelitian penulis yang bertujuan untuk mengetahui keadaan/kondisi terumbu karang untuk penentuan status terumbu karang saat itu sehingga dapat memberikan masukan dalam pengelolan terumbu karang secara tepat dan benar dapat dilaksanakan. Penelitian ini dilaksanakan tanggal 22 Oktober 1998 hingga 29 Oktober 1998 di Pulau Pamegaran, Pulau Panjang Kecil, Pulau Karang Bongkok, Pulau Kotok Kecil dan Karang Pasangan Tuan Kepulauan Seribu, Jakarta Utara.
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Judul: Algorithm construction of HLI hash function
Abstrak: Cryptography is a study of mathematical techniques related to aspects of information security regarding on confidentiality, data integrity, entity authentication, and data origin authentication. Data integrity is a service, which is associated with the conversion of data carried out by unauthorized parties. To maintain data integrity, one can use hash functions. An hash function is a computationally efficient function to map an arbitrary length bitstring to a fixed length bitstring called as hash value. The use of hash function in maintaining the information integrity and authentication is in digital signatures, virus protection, and software distribution. Illustration of the hash function in the integrity and authentication of information that is emailed as follow. The sender sends the information and hash value to the recipient. If the hash value of the information is equal to the hash value that is sent by the sender, then information has not been changed. Otherwise the information has been changed. An hash function has two properties, one way and collision resistance. An hash function is called one way if it is computationally infeasible to find any input such that when given any hash value . Meanwhile an hash function is called collision resistant if it is computationally infeasible to find any two inputs where such that . The purpose of this study is to construct a HLI hash function algorithm, to analyze the speed and security of the hash functions as a results of construction. Furthermore, it is to compare it with SWIFFT. Hash function is constructed based on the result of algebraic operations on modular polynomial ringwith . Modular polynomial ring noted as is a set of all polynomials of degree at most with coefficients in . can be represented as a set of integer vector of modulo in dimension . So, it is simple to implement in a computer. In vector operations, is lattice . Furthermore, alattice that is defined from certain polynomial ring is called ideal lattice. HLI hash function is consists of addition and multiplication algorithm in the ring. Addition algorithm consists of sumation operations of modulo and multiplication consists of multiplication operations of modulo . Generally, algorithm of HLI hash function consists of multiplication operations of modulo and addition operations of modulo . However, if the input is binary number then multiplication algorithm only consists of multiplication operation of modulo , so algorithm of HLI hash function consists of multiplication operations of modulo and addtion operations of modulo . An hash function is secured if it has two properties, i.e., one way and collision resistance. HLI hash function hash is one way, it is following the proof of Micciancio. It is has collision resistant because of polynomial is irreducible over and monic. Moreover, it is proved that for every unit vector , the vector is small vector. If the input of hash function is a binary number then HLI hash function only involves addition operations of modulo . So the time that used almost same with SWIFFT. The excellence of HLI hash function is the key size smaller than SWIFFT. This effect on
Keyword: hash function, modular polynomial ring, lattice