Judul: Inventarisasi Dan Karakterisasi Kondisi Fisika Kimia Perairan Karst Di Kabupaten Bogor, Jawa Barat
Abstrak: Karst merupakan kawasan berbatuan karbonat yang memiliki kandungan air melimpah. Langkah awal yang dilakukan dalam upaya pengelolaan adalah inventarisasi dan karakterisasi kondisi perairan karst terutama dalam hal fisikakimia perairan. Penelitian dilaksanakan pada bulan Januari sampai April 2015, di Kabupaten Bogor, Jawa Barat. Analisis data meliputi kesamaan karakteristik antar kawasan, analisis komponen utama, dan tingkat kesuburan perairan. Persebaran kawasan karst di Kabupaten Bogor dikelompokkan menjadi dua formasi utama diantaranya Formasi Klapanunggal (Klapanunggal, Cibinong, dan Citereup) dan Formasi Bojongmanik (Ciampea, Jasinga, Leuwiliang, Cigudeg, dan Ciseeng). Hasil analisis menunjukkan bahwa perairan dengan lokasi yang sama memiliki karakteristik yang sama. Tingkat kesuburan perairan Karst Ciampea dan Klapanunggal bersifat mesotrofik dan perairan Karst Ciseeng bersifat eutrofik. Karst Klapanunggal memiliki sumber bahan tambang dan mineral yang tinggi. Karst Ciseeng memiliki bentuk yang unik dan dimanfaatkan sebagai wisata pemandian air panas. Karst Ciampea dimanfaatkan untuk irigasi pertanian dan keperluan domestik.
Keyword: ekosistem perairan, karst, kualitas air, status kesuburan, potensi ekologis

Judul: Struktur Komunitas Perifiton Di Perairan Cekungan Karst Cileungsi, Kabupaten Bogor, Jawa Barat
Abstrak: Kawasan karst merupakan topografi unik yang terbentuk akibat endapan aliran air pada bebatuan karbonat (berupa kapur, dolomit, atau marmer). Penelitian ini bertujuan untuk mendeskripsikan struktur komunitas perifiton dan keterkaitannya dengan kualitas fisika-kimia air di cekungan karst Cileungsi, Kabupaten Bogor, Jawa Barat. Penelitian ini dilakukan pada bulan Februari hingga Maret dengan interval waktu pengambilan contoh 2 minggu. Komunitas perifiton di cekungan karst Cileungsi terdiri atas 5 kelas, yaitu Bacillariophyceae (9 genera), Cyanophyceae (7 genera), Chlorophyceae (6 genera), Dinophyceae (1 genus), dan Euglenophyceae (1 genus). Perbedaan diversitas total (β) di cekungan karst Cileungsi lebih ditentukan oleh komponen βrich atau nestedness dibandingkan dengan β-3 (turnover). Hal ini disebabkan stasiun yang memiliki diversitas yang rendah tersusun atas stasiun yang memiliki diversitas yang tinggi. Pada Stasiun 1 parameter yang berpengaruh nyata terhadap perifiton adalah nitrat, ortofosfat, alkalinitas, pH, dan kekeruhan. (R²= 99%), sedangkan pada Stasiun 2 parameter yang berpengaruh nyata terhadap perifiton adalah nitrat, ortofosfat, alkalinitas, pH, dan kekeruhan. (R²= 99%).
Keyword: cekungan karst, diversitas, kualitas air, komunitas perifiton

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