Judul: Kajian Kualitas Air Beberapa Sungai di Pesisir Kecamatan Indramayu, Kabupaten Indramayu, Jawa Barat (Suatu Tinjauan Bagi Kegiatan Perikanan)
Abstrak: Sejak tahun 1994 mulai terjadi beberapa kegagalan pada panen udang di Kabupaten Indramayu dan mencapai puncaknya pada tahun 1996 dimana tambak udang mengalami kegagalan total. Salah satu faktor penyebab kegagalan panen tersebut adalah menurunnya kualitas dan kuantitas air (terutama air tawar) yang digunakan. Di Kecamatan Indramayu terdapat beberapa sungai yang memasok air tawar ke tambaktambak yang terdapat pada empat desa di wilayah pesisir. Sungai-sungai tersebut yaitu Sungai Cimanuk yang melintasi Desa Pabean Udik dan Brondong, Sungai Cabang Cimanuk yang bermuara ke Desa Brondong, Sungai Prajagumiwang di Desa Karangsong, d?ln Sungai Prawirakepolo di Desa Singajaya.
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Judul: Pemetaan Intrusi Air Laut Berdasarkan Kualitas Airtanah di Kabupaten Indramayu, Jawa Barat
Abstrak: Kabupaten Indramayu merupakan lumbung padi Pulau Jawa yang terletak di daerah pesisir sehingga airtanah menjadi sumber daya andalan untuk irigasi pertanian. Eksplorasi airtanah yang berlebihan dapat menyebabkan terjadinya intrusi air laut. Intrusi air laut ke dalam akuifer dapat diprediksi dan ditentukan dengan program Jaringan Saraf Tiruan (JST). Penelitian ini bertujuan untuk menentukan area yang terkena dampak intrusi dan menentukan peta zonasi intrusi berdasarkan kualitas airtanah, antara lain total dissolved solid (TDS), salinity, dan electrical conductivity (EC). Penelitian dilakukan pada Februari 2017 di 33 kecamatan dengan 83 titik sampling. Kabupaten Indramayu memiliki luas area persawahan sekitar 57,94%, dalam bentuk dataran rendah dengan area sedimen terletak di timur laut. Air permukaan didapat dari DAS Cimanuk, Cipunegara, dan Cipanas; sedangkan airtanah tidak tertekan telah dieksploitasi berlebihan untuk sumur irigasi pada musim kemarau. Kabupaten Indramayu memiliki topografi terletak pada 0 – 100 meter di atas permukaan air laut dengan rerata kemiringan 0 – 2%, sehingga kabupaten ini terendam air pada musim hujan. Akuifer bebas terletak pada 3 – 30 meter di bawah permukaan tanah, dengan ketebalan sekitar 15 – 20 meter; yang mengalir dari selatan ke utara. Berdasarkan hasil penelitian, didapatkan nilai kualitas airtanah pada daerah utara dan timur lebih besar dibandingkan selatan, dikarenkan pesisir pantai terletak sepanjang utara dan timur.
Keyword: EC, intrusi, salinitas, Kabupaten Indramayu, TDS

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