Judul: Karakteristik Nitrat Nitrit dan Ammonia dalam Proses Percampuran di Perairan Muara Sungai Bengawan Solo Gresik Jawa TImur Periode Juli-Desember 2001
Abstrak: Senyawa nitrogen merupakan salah satu senyawa yang sangat penting dalam menunjang ekositem perairan. Nitrat dimanfaatkan oleh fitoplankton dalam proses fotosintesis. Hal ini berbeda dengan nitrit dan ammonia yang dapat bersifat raeun bagi organisme dan keberadaannya (termasuk nitrat) dikendalikan oleh proses-proses fisika, kimia dan biologi perairan. Dalam studi ini keterkaitan proses-proses tersebut terhadap nitrogen akan dikaji di perairan muara Sungai Bengawan Solo mengingat informasi tentang hal ini yang masih terbatas. Penelitian ini bertujuan untuk mengetahui karakteristik distribusi spasial dan temporal nitrogen dalam kaitannya dengan proses-proses fisika-kimia perairan estuaria di muara SWlgai Bengawan Solo, Gresik, Jawa Timur. Penelitian ini dilaksanakan pad a bulan Juli-Desember 2001 di perairan muara Sungai Bengawan Solo. Peralatan yang digunakan terdiri dari botol kemmerer, tali penduga, floating draft, turbiditimeter, termometer, seichi disc, handrefraktometer, ;pektrofotometer dan peralatan pengukuran kualitas air. Bahan yang digunakan adalah bahan untuk analisa DO, nitrat, nitrit dan an1l11Onia serta kertas lakmus universal untuk mengukur derajat keasaman (pI-I).
Keyword: 

Judul: Struktur Komunitas Fitoplankton serta Hubungannya dengan Parameter Fisika dan Kimia Perairan di Muara Sungai Bengawan Solo Ujung Pangkah Gresik Jawa Timur.
Abstrak: Penelitian ini bertujuan untuk mengetahui struktur komunitas fitoplankton yang meliputi kelimpahan, keanekaragaman, keseragaman, dan dominansi serta melihat sejauh mana hubungan fitoplankton dengan parameter fisika - kimia perairan di lokasi penelitian. Penelitian dilakukan pada bulan Juli sampai dengan bulan Desember 2001, dimana pengambilan sampel dilakukan tiap-tiap tanggal 30. Hasil pengukuran suhu perairan di muara Sungai Bengawan Solo selama pengamatan bulan Juli - Desember berkisar antara 25,0 - 32,0 °C dengan rata-rata 29,14 "C. Pengukuran terhadap kondisi kecerahan perairan selama pengamatan secara keseluruhan menunjukkan perbedaan yang mencolok. Nilai kecerahan yang terdapat pada perairan ini berkisar antara 0,01 - 0,37 meter. Nilai kekeruhan (NTU) yang terukur berkisar antara 17,5 - 350 NTU. Hasil pengukuran salinitas berkisar antara 0,0 - 35,0 %0. Nilai pH perairan berkisar antara 6,0 - 8,0 dengan rata-rata pH 6,9. Hasil pengukuran kandungan fosfat berkisar antara 0,0050 - 0,2210 ppm. Pengukuran temadap kandungan nitrat berkisar antara 0,059 - 0,657 ppm.
Keyword: 

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