Judul: Penentuan Status Ekologi Menggunakan Indeks Biotik AMBI dengan Makrozoobentos di Lubuk Damar, Kecamatan Seruway, Aceh Tamiang
Abstrak: Pesisir Lubuk Damar termasuk wilayah yang memiliki potensi mangrove alami dan wilayah pesisir yang cukup luas sehingga dapat memicu terjadinya gangguan atau tekanan lingkungan. Hal ini dapat mempengaruhi organisme air, khususnya makrozoobentos. Makrozoobentos merupakan organisme indikator kesehatan lingkungan perairan. Penelitian ini bertujuan untuk menganalisis status ekologi berdasarkan makrozoobentos menggunakan indeks biotik AMBI di pesisir Lubuk Damar, Seruway, Aceh Tamiang. Penelitian dilaksanakan pada bulan Agustus 2017 dan Januari 2018 pada dua stasiun. Sampel makrozoobentos diambil menggunakan metode transek garis yang ditarik dari pasang tertinggi hingga 500 meter ke arah laut. Makrozoobentos yang ditemukan terdiri dari sembilan filum, 12 kelas, dan 72 spesies. Nilai AMBI yang diperoleh berkisar antara 0,56-1,42 yang menunjukkan bahwa pesisir Lubuk Damar tergolong tidak terganggu dan beberapa Substasiun mengalami gangguan ringan. Nilai MAMBI berkisar antara 0,66-0,97 yang menunjukkan bahwa status ekologi masih tergolong baik dan beberapa Substasiun tergolong sangat baik. Secara keseluruhan, hasil penelitian menunjukkan bahwa pesisir Lubuk Damar masih tergolong relatif baik dengan tingkat gangguan yang masih tergolong ringan.
Keyword: AMBI, ekosistem mangrove, makrozoobentos, wilayah pesisir, status ekologi

Judul: Hubungan Kerapatan Mangrove dengan Komunitas Makrozoobentos di Kawasan Lubuk Damar, Kecamatan Seruway, Kabupaten Aceh Tamiang
Abstrak: Pemanfaatan vegetasi mangrove yang tidak berkelanjutan menyebabkan terganggunya ekosistem mangrove sehingga berdampak pada terganggunya komunitas makrozoobentos. Penelitian ini bertujuan untuk menganalisis hubungan kerapatan mangrove dengan komunitas makrozoobentos di kawasan Lubuk Damar, Kecamatan Seruway, Kabupaten Aceh Tamiang. Penelitian dilaksanakan pada bulan Agustus 2017 dan Januari 2018 pada tiga stasiun. Pengambilan data vegetasi mangrove dilakukan dengan metode kuadrat sedangkan makrozoobentos dan sedimen menggunakan corer. Mangrove yang ditemukan terdapat enam jenis. Makrozobentos yang ditemukan terdapat sembilan filum, 14 kelas, 30 ordo, 55 famili, dan 59 genus Keanekaraman, keseragaman, jumlah jenis tertinggi terdapat pada Stasiun 3. Dominansi dan kepadatan tertinggi pada Stasiun 2. Kerapatan mangrove di ekosistem Lubuk Damar mempunyai hubungan yang sangat kuat terhadap indeks keanekaragaman dan indeks keseragaman makrozoobentos. Kepadatan makrozooobentos kelompok Polycaheta, Anopla, Scaphopoda, Bivalvia, Anthozoa, dan Holothuridea dipengaruhi oleh kerapatan mangrove.
Keyword: Ekosistem mangrove, indeks keanekaragaman, indeks keseragaman

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