Judul: Evaluasi Pertumbuhan Mangrove dengan Teknik Guludan di Kawasan Muara Angke, Jakarta Utara
Abstrak: Kegiatan penanaman mangrove yang dilakukan oleh berbagai pihak di Kawasan Muara Angke Jakarta Utara bertujuan menjaga kelestarian ekosistem pesisir khususnya dengan melakukan rehabilitasi dan restorasi penanaman mangrove. Penelitian ini bertujuan menghitung tingkat keberhasilan tanaman dengan melihat presentase tumbuh pasca penanaman serta mengukur diameter dan tinggi batang tanaman. Berdasarkan penelitian yang dilakukan, kegiatan penanaman yang dilakukan kurang berhasil (persen tumbuh tergolong rendah) pada semua lokasi. Presentase tumbuh rata-rata dari kelima lokasi adalah: lokasi 1 (14.53%), lokasi 2 (29.25%), lokasi 3 (18.01 %), lokasi 4 (40.45%), dan lokasi 5 (44.3%). Riap diameter dari keempat lokasi adalah: lokasi 1 (0.36 cm/th), lokasi 2 (0.37 cm/th), lokasi 3 (0.37 cm/th), lokasi 4 (0.40 cm/th). Riap tinggi dari keempat lokasi adalah: lokasi 1 (0.42 cm/th), lokasi 2 (0.44 cm/th), lokasi 3 (0.36 cm/th), lokasi 4 (0.40 cm/th). Pengukuran riap pada lokasi 5 tidak dilakukan karena tanaman masih berumur 1 tahun. Salah satu langkah yang dapat dilakukan untuk meningkatkan presentase tumbuh adalah dengan melakukan pemeliharaan intensif serta menjaga kondisi lingkungan.
Keyword: evaluasi, rehabilitasi mangrove, pertumbuhan, muara angke, guludan

Judul: Evaluation of the Growth of Mangrove as a Result of Rehabilitation with Guludan Technique at Elang Laut Area, Muara Angke
Abstrak: Kawasan Elang Laut merupakan salah satu kawasan mangrove yang berada di pesisir Muara Angke, Jakarta Utara. Upaya pelestarian hutan mangrove di Kawasan Elang Laut dilakukan melalui rehabilitasi dengan teknik guludan. Penelitian ini bertujuan untuk mengukur pertumbuhan mangrove, mengamati kondisi kesehatan mangrove, dan menentukan tingkat keberhasilan penanaman mangrove hasil rehabilitasi di Kawasan Elang Laut. Data yang diambil pada penelitian ini yaitu pertumbuhan anakan Rhizophora mucronata dan kondisi kesehatan mangrove. Kondisi lahan penanaman meliputi kondisi substrat, faktor klimatis dan kualitas perairan. Berdasarkan penelitian yang dilakukan, setelah satu tahun penanaman kegiatan rehabilitasi dengan teknik guludan yang dilakukan di Kawasan Elang Laut dikategorikan berhasil karena menghasilkan persentase survival rate sebesar 97,27% dengan pertumbuhan diameter batang rata-rata sebesar 1,42 cm, tinggi anakan rata-rata sebesar 79,71 cm, rata-rata jumlah daun sebanyak 25 helai daun, dan rata-rata jumlah ruas sebanyak 8 ruas, dimana 64% dari jumlah anakan dalam kondisi sehat., Elang Laut Area is one of the mangrove areas on Muara Angke coast in North Jakarta. Rehabilitation with the guludan technique is used in Elang Laut Area to maintain mangrove forest. This study aims to measure the growth of mangroves, observe the health condition of the mangroves, and determine the success rate of rehabilitated mangroves planting in Elang Laut Area. The data collected in this study includes the growth of Rhizophora mucronata seedlings and the health condition of mangroves. The planting site conditions include substrate conditions, climatic factors, and water quality. This research clearly show that, after one year of rehabilitation activities with the guludan technique carried out in Elang Laut Area, it the rehabilitation activities are categorized as successful due to achieving a survival rate percentage of 97,27%, average stem diameter growth of 1,42 cm, average height of 79,71 cm, average leaf count of 25 leaves, and an average internode count of 8 internodes, where 64% of the seedlings are in a healthy condition.
Keyword: Elang Laut Area, Evaluation of planting, Mangrove, Rehabilitation

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