Judul: Karakteristik biota karang dan ikan karang penyusun ekosistem terumbu karang di Gosong Pabelokan Kepulauan Seribu Jakarta
Abstrak: Penelitian ini dilakukan di Gosong Pabelokan, Teluk Jakarta. pada bulan April- Juni 1997. Penelitian ini be1iujuan untuk mengetahui kondisi ekosistern terumbu karang dan ikan karang serta parameter fisika-kimia yang mendukung terumbu karang. Metode yang digunakan untuk pengamatan terumbu karang adalah metode transek garis sepanjang 100 meter, pada kedalaman 3 dan 10 meter. Komponen dasar yang diamati digolongkan berdasarkan Structural Analysis of Life Form (English et al., 1994). Nilai penutupan yang di peroleh di dasarkan pada persentase penutupan yang dicakup oleh transek garis. Pengamatan ikan karang dilakukan dengan metode pencacahan langsung (Visual census). Data yang diperoleh dari hasil penelitian dianalisis berdasarkan persentase penutupan biota karang, kelimpahan jenis ikan karang, indeks keanekaragaman (H'), indeks keseragarnan (E), dan indeks dominansi (C).
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Judul: Kajian kerusakan ekosistem terumbu karang akibat penangkapan ikan hias dan pengambilan bunga karang di Kelurahan Pulau Panggang Kepulauan Seribu Jakarta Utara
Abstrak: Penelitian ini dilakukan untuk mengetahui tingkat kerusakan akibat aktivitas penangkapan ikan hias dan pengambilan karang hias serta menganalisis kondisi terumbu karang pada lokasi pengambilan ikan hias dan karang hias di Kelurahan Pulau Panggang Kepulauan Seribu. Monitoring ekosistem terumbu karang sebagai pengamatan untuk melihat tingkat kerusakan ekosistem terumbu karang akibat penangkapan ikan hias dilakukan di sekitar Kelurahan Pulau Panggang, Kepulauan Seribu, Jakarta Utara. Pengamatan dilakukan pada tanggal 10-11 November 2001. Jumlah keseluruhan lokasi pengamatan adalah 3 stasiun yaitu gosong P. Kotok Kecil (posisi: S05 41' 22.20" E 106 32' 36.7')', Gosong P. Balik Layar (posisi: S05 43' 56.7" E 106 33' 39.6") dan Gosong P. Panggang (posisi: S 05 44' 50.3" E 106 35,33.9"). Data yang diperoleh merupakan data primer yang meliputi pengambilan data terumbu karang dan data ikan. Metode yang digunakan dalam pengambilan data di reef flat (Kedalaman ± 1 m) penyelam melakukan snorkling di permukaan perairan tepatnya di atas transek, sedangkan pengambilan data pada reef slope (kedalaman ± 3 m) menggunakan peralatan scuba diving. Data karang diambil berdasarkan genus terumbu karang dengan metode Transek Garis Menyinggung/Line Intercept Transect (LIT). Hasil akhirnya memperlihatkan persen penutupan (percent cover). Data ikan yang diambil meliputi data spesies ikan karang. dengan menggunakan metode visual sensus Selain pengumpulan data ekosistem terumbu karang dilakukan juga pengumpulan data sosial ekonomi nelayan ikan hias dan karang hias. Pengumpulan data sosial ekonomi ini dilakukan dengan cara melakukan wawancara langsung dengan nelayan yang terdapat di P. Panggang. Tingginya penangkapan ikan hias dan bunga karang di sekitar daerah Pulau Kotok ini, menyebabkan persen penutupan karang mati lebih tinggi dibandingkan 2 stasiun lainnya. Diduga penggunaan racun potasium cyanida telah menyebabkan tingginya penutupan karang mati didaerah ini.
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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