Judul: Pengetahuan Lokal Petani Kopi Gayo dalam Pengelolaan Sistem Agroforestri di Desa Mude Nosar, Aceh Tengah
Abstrak: Desa Mude Nosar di Kecamatan Bintang, Kabupaten Aceh Tengah, Provinsi Aceh, didominasi oleh Suku Gayo Lut dengan mata pencaharian utama bertani. Tujuan penelitian (i) mengidentifikasi pengetahuan lokal yang diterapkan dalam pengelolaan sistem agroforestri, (ii) mengidentifikasi faktor yang mempengaruhi pemilihan jenis tanaman budidaya, (iii) menganalisis komposisi, struktur tegakan, dan keanekaragaman vegetasi pada sistem agroforestri di Desa Mude Nosar. Penelitian dilakukan dengan metode wawancara 30 responden dan analisis vegetasi. Hasil penelitian menunjukkan bahwa mata pencaharian utama masyarakat adalah petani Kopi Gayo. Faktor yang memengaruhi pemilihan jenis tanaman adalah nilai ekonomi dengan mempertimbangkan pengetahuan lokal secara turun-temurun. Pengetahuan lokal dalam mengelola sistem agroforestri selaras dengan upaya konservasi. Hal tersebut ditunjukkan dengan adanya multi- strata tajuk dari Kopi Gayo dengan pohon penaung Lamtoro. Pemanenan jenis-jenis tersebut adalah dari buah, sehingga batang tetap tegak dan mampu membantu dalam konservasi air/tanah, serta mencegah erosi. Proses regenerasi berjalan normal ditunjukkan pada 2 dari 5 plot penelitian. Spesies dominan pada level semai, tumbuhan bawah, dan pancang secara berurutan adalah Rumput kerbau dan Kopi, sedangkan Lamtoro mendominasi pada tingkat tiang dan pohon. Nilai keanekaragaman jenis (H’) dan kekayaan jenis (Dmg) termasuk dalam kategori rendah, sehingga diperlukan pengayaan baik individu/spesies. Maka dari itu, pengelolaahan lahan serta pengayaan tanaman pada lahan agroforestri dibutuhkan untuk meningkatkan keanekaragaman jenis yang juga tetap mendukung perekonomian masyarakat.
Keyword: Composition, Diversity of vegetation, Local culture, Socio-economic, Stand structure

Judul: Identification of Pests and Diseases along with Their Control in  the Gayo Coffee (Coffea arabica) Agroforestry System in Central Aceh
Abstrak: Sistem agroforestri adalah sistem pengelolaan lahan yang mempertimbangkan aspek sosial, ekonomi dan ekologi. Kopi Gayo (Coffea arabica) merupakan komoditi utama masyarakat Desa Mude Nosar, Aceh Tengah dengan sistem yang digunakan adalah sistem agroforestri. Disisi lain, serangan hama dan penyakit k opi Gayo menyebabkan penurunan produktivitas dan penelitian terkait identifikasi hama serta penyakit pada sistem agroforestri kopi Gayo masih sangat terbatas. Tujuan penelitian ini adalah i) menganalisis komposisi, struktur, dan keanekaragaman vegetasi, ii) mengidentifikasi jenis hama dan penyakit pada Kopi Gayo dan penaungnya, iii) menghitung intensitas serangan hama dan penyakit pada sistem agroforestri k opi Gayo, serta iv) mengidentifikasi potensi pengendalian hama dan penyakit terpadu pada sistem agroforestri kopi Gayo di Desa Mude Nosar. Metode yang digunakan adalah purposive sampling dan analisis vegetasi serta menghitung serangan hama dan penyakit. Gejala serangan diidentifikasi di Laboratorium Patologi Hutan dengan melihat struktur makroskopis dan mikroskopis cendawan. Hasil penelitian menunjukkan bahwa rumput kerbau (Paspalum conjugatum) dan kopi Gayo secara berturut-turut mendominasi tingkat tumbuhan bawah dan pancang. Lamtoro (Leucaena leucocephala) mendominasi tingkat semai, tiang dan pohon. Keanekaragaman jenis (H’) tingkat semai dan tumbuhan bawah termasuk sedang dan tingkat pancang, tiang, dan pohon termasuk rendah. Struktur tegakan membentuk kurva J terbalik. Hama yang ditemukan adalah kutu loncat (Heteropsylla cubana) dan ulat jengkal (Hyposidra talaca). Penyakit yang ditemukan yaitu antraknosa dan karat daun. Intensitas serangan hama kutu loncat, penyakit antraknosa dan karat daun masing-masing dibawah 30%. Pengendalian hama dan penyakit pada sistem agroforestri kopi Gayo secara terpadu dengan pengelolaan agroforestri secara organik dengan pemanfaatan limbah kulit kopi dan kotoran ternak, serta dengan pemanfatan musuh alami. Musuh alami yang berpotensi yaitu Trichoderma harzianum, semut rangrang (Oecophylla smaragdina), dan laba-laba (Araneae)., Agroforestry is a land management system which considers social, economic and ecological aspects. Gayo coffee (Coffea arabica) is the main commodity which planted by local community of Desa Mude Nosar, Central Aceh using agroforestry system. On the other hand, Gayo coffee pests and diseases reduce the productivity and only a few studies have been undertaken to identify pests and diseases in Gayo coffee with agroforestry system. The study aimed to i) analyze the composition, structure, and diversity of vegetation, ii) to identify the types of pests and diseases in Gayo Coffee and its shade, iii) to calculate the intensity of pest and disease attacks on Gayo coffee in agroforestry system, and iv) to identify the potential of integrated pest control and disease in the Gayo coffee with agroforestry system in Desa Mude Nosar. The method used in this study was purposive sampling and vegetation analysis along with calculating pest and disease attacks. Symptoms of the attack were identified at Forest Pathology Laboratory by looking at the macroscopic and microscopic structures of the fungus. The results showed that rumput k erbau (Paspalum conjugatum) and Gayo coffee dominated the understorey and sapling levels. Lamtoro (Leucaena leucocephala) dominates the seedling, pole and tree stake. Species diversity (H') of seedlings and understorey levels was moderate and the level of saplings, poles, and trees was low. The stand structure forms an inverted J curve. The pests found were fleas (Heteropsylla cubana) and black looper (Hyposidra talaca).
Keyword: Agroforestry, Gayo coffee, Lamtoro, Agroforestry, Gayo coffe, Lamtoro

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