Judul: Kualitas air dan tingkat pencemaran perairan Danau Ebony, Pantai Indah Kapuk terkait dengan upaya pengelolaan
Abstrak: Bahan-bahan pencemar di perairan Danau Ebony diduga berasal dari limbah domestik (aktivitas antropogenik). Tingkat pencemaran perairan perlu dikaji untuk mengetahui kesesuaian air dengan peruntukannya. Tujuan dari penelitian ini adalah menentukan tingkat pencemaran perairan di Danau Ebony berdasarkan dua metode, yaitu Indeks Pencemaran (IP) dan Indeks STORET. Hasil penelitian menunjukkan bahwa tingkat pencemaran Danau Ebony berdasarkan Indeks Pencemaran (IP) tergolong kondisi tercemar ringan pada bagian permukaan, dengan kisaran nilai 1,6 hingga 4,9. Hasil yang didapat pada bagian dasar juga tidak jauh berbeda, yaitu berkisar antara 1,4 hingga 4,6 dan tergolong ke dalam kondisi tercemar ringan. Hasil yang berbeda diperoleh jika dievaluasi menggunakan Indeks STORET. Tingkat pencemaran tergolong kedalam kondisi tercemar ringan hingga tercemar berat pada bagian permukaan, dengan nilai kisaran -9 hingga -35. Tingkat pencemaran pada bagian dasar tergolong dalam kondisi tercemar sedang hingga tercemar berat, dengan nilai kisaran -16 hingga - 55. Parameter kualitas air yang tidak sesuai dengan baku mutu di perairan Danau Ebony adalah COD, BOD5, NO2, P total, pH, DO, TSS, dan TDS., Pollutants materials in Lake Ebony is thought to be derived from domestic waste from nearby housing complex. The pollution level in this lake is needed to be assessed to find out the suitability of the water and its designation. The purpose of this study is to determine the level of pollution based on two methods, Pollution Index and STORET. Results show that the level of pollution in Lake Ebony based on Pollution Index is considered lightly polluted in the surface (1.6 to 4.9) and slightly different in the bottom (1.4 to 4.6) and also considered as lightly polluted. Different result was seen from STORET Index. The level of pollution in the surface ranged from lightly polluted to severely polluted (-9 to - 35) while same thing occurred in the bottom (-16 to -55). The water parameters that exceeded the normal limit are COD, BOD5, NO2, P total, pH, DO, TSS, and TDS.
Keyword: Indeks Pencemaran, Indeks STORET, kualitas air, limbah domestik

Judul: Kualitas air Danau Ebony di kawasan Bukit Golf Mediterania, Pantai Indah Kapuk, Jakarta Utara
Abstrak: Danau Ebony merupakan danau buatan yang difungsikan sebagai pengendali banjir dan menambah nilai estetika perumahan di sekitarnya. Penelitian dilakukan dimaksudkan untuk mengevaluasi apakah operasional pengelolaan Danau Ebony mampu memperbaiki kualitas air danau. Penelitian ini dilakukan pada bulan Maret 2014-Februari 2015 dengan interval waktu satu bulan. Analisis data yang digunakan dalam penelitian ini adalah Indeks Pencemaran dan Indeks STORET. Tingkat pencemaran danau Ebony berdasarkan Indeks STORET memiliki kisaran nilai -40 sampai -52. Nilai Indeks Pencemaran perairan Danau Ebony yang diperoleh untuk permukaan dan dasar perairan berkisar antara 1,54 sampai 10,26. Kondisi Danau Ebony yang tercemar dicirikan oleh parameter-parameter yang melebihi baku mutu air kelas III PP no 82 tahun 2001, di antaranya COD, BOD5, Nitrit, H2S. Status perairan Danau Ebony berdasarkan Indeks Pencemaran tergolong tercemar ringan hingga tercemar berat. Berdasarkan Indeks STORET status kualitas air Danau Ebony menunjukkan kondisi tercemar berat pada setiap stasiun dengan kecenderungan musim kemarau lebih tinggi dibandingkan musim hujan.
Keyword: Ebony lakes, Pollution, Quality standards

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