Judul: Dinamika Bahan Organik dan Status Kualitas Air Danau Crown Golf, Pantai Indah Kapuk, Jakarta Utara
Abstrak: Danau Crown Golf berfungsi sebagai danau hias, namun tingginya limbah organik telah mengakibatkan kondisi perairannya berbusa, berbau, berwarna, dan dangkal. Penelitian ini bertujuan untuk mengintepretasi dinamika bahan organik dan menentukan tingkat pencemaran perairan. Pengamatan dilakukan pada bulan Januari hingga Desember 2016 di empat stasiun pengamatan. Baku mutu air kelas II digunakan untuk menentukan analisis deskriptif dinamika bahan organik sementara tingkat pencemaran ditentukan dengan indeks pencemaran dan indeks STORET. Hasil penelitian menunjukkan tidak ada tingkat kesamaan karakteristik kualitas air antar stasiun pengamatan. Dinamika bahan organik berbeda antar musim. Tiap musim tidak memenuhi baku mutu air kelas II berdasarkan PP Nomor 82 Tahun 2001. Danau Crown Golf telah mengalami pencemaran bahan organik yang tinggi pada musim hujan. Indeks yang paling menggambarkan pencemaran adalah indeks pencemaran Nemerrow dengan kondisi cemar ringan hingga cemar sedang.
Keyword: bahan organik, Danau Crown Golf, kualitas air, pencemaran

Judul: Status kualitas air Danau Crown Golf, Pantai Indah Kapuk, Jakarta Utara
Abstrak: Danau Crown Golf merupakan perairan buatan yang terletak di antara perumahan warga sehingga banyak menerima bahan pencemar dari limbah domestik. Hal ini dikhawatirkan akan menurunkan kualitas perairan danau. Penelitian dilakukan dimaksudkan untuk menentukan status pencemaran perairan di Danau Crown Golf berdasarkan analisis Indeks Pencemaran (IP) dan Indeks STORET. Penelitian dilaksanakan pada Bulan November 2014–Februari 2015, dengan interval satu bulan. Kondisi perairan danau secara visual berwarna kehijauan dan berbau. Analisis contoh air dan sedimen menunjukkan bahwa terdapat beberapa parameter kualitas air yang tidak memenuhi standar baku mutu kelas III menurut PP No 82 Tahun 2001, di antaranya adalah BOD5, COD, nitrit, dan sulfida. Indeks Pencemaran menunjukkan bahwa kondisi perairan danau tercemar ringan hingga sedang dengan kisaran nilai 4,3 hingga 9,4. Hasil ini berbeda dari status yang didapat dengan menggunakan Indeks STORET, diketahui kondisi perairan danau tercemar sedang hingga berat dengan kisaran nilai -36 hingga -38. Kondisi perairan Danau Crown Golf termasuk kedalam kategori tercemar ringan sampai dengan berat.
Keyword: Pollution Index, STORET Index, water quality

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