Judul: Valuasi Sumberdaya Mangrove sebagai Pertimbangan dalam Upaya Rehabilitasi Ekosistem Mangrove di Muara Sungai Sesayap Kabupaten Tana Tidung.
Abstrak: Mangrove mempunyai jasa ekosistem yang bernilai ekonomi. Manfaat mangrove dapat dirasakan secara langsung dan tidak langsung. Pengelolaan mangrove menjadi perhatian penting seiring terjadinya penurunan mangrove akibat konversi lahan. Penelitian ini bertujuan untuk mengidentifikasi dan menghitung nilai ekonomi sumberdaya ekosistem mangrove, serta efektivitas tingkat rehabilitasi untuk bahan pertimbangan dalam pengelolaan ekosistem mangrove di muara Sungai Sesayap, Kabupaten Tana Tidung. Metode yang digunakan pada penelitian ini adalah analisis kuantitaif yaitu analisis effort of production dan benefit transfer. Ekosistem mangrove di muara Sungai Sesayap dalam satu dekade ini telah terjadi penurunan luasan sebesar 30,15%. Nilai ekonomi total (NET) ekosistem mangrove di muara Sungai Sesayap sebesar Rp 204.778.669/ha/tahun. Nilai efektivitas rehabilitasi ekosistem mangrove di daerah rehabilitasi muara Sungai Sesayap mencapai 50,45%. Nilai efektivitas rehabilitasi menunjukan efektif dan dapat menjadi bahan pertimbangan bagi perencanaan penganggaran (budgeting) dalam mengelola ekosistem mangrove.
Keyword: ekonomi sumberdaya, mangrove, valuasi, rehabilitasi

Judul: Penilaian Ekonomi dan Strategi Pengelolaan Ekosistem Mangrove Pasca Rehabilitasi di Kelurahan Wonorejo, Kota Surabaya.
Abstrak: Kerusakan hutan mangrove di Kelurahan Wonorejo yang diakibatkan oleh pembalakan liar dan konversi hutan mangrove berdampak pada berkurangnya luas hutan mangrove serta hilangnya beberapa fungsi dan manfaat ekosistem mangrove. Kondisi tersebut membuat masyarakat dan pemerintah mulai menyadari pentingnya menjaga kelestarian ekosistem mangrove, sehingga mereka mulai melakukan kegiatan rehabilitasi. Penelitian ini bertujuan untuk (1) menganalisis kondisi ekosistem mangrove di Kelurahan Wonorejo sebelum dan sesudah dilakukannya kegiatan rehabilitasi, (2) mengestimasi nilai ekonomi total dari ekosistem mangrove di Kelurahan Wonorejo, dan (3) menganalisis optimasi dinamik dan strategi pengelolaan ekosistem mangrove yang berkelanjutan di Kelurahan Wonorejo. Penelitian menggunakan metode penelitian survei dan data yang diperoleh dianalisis dengan analisis deskriptif kuantitatif, nilai ekonomi total, sistem dinamik, dan weighted sum model. Hasil penelitian menunjukkan kondisi hutan mangrove lebih baik setelah dilakukan rehabilitasi dilihat dari pertambahan luas, jenis, kerapatan serta perubahan pemanfaatan ekosistem mangrove Wonorejo. Hasil estimasi nilai ekonomi total ekosistem mangrove Wonorejo yaitu sebesar Rp 5.533.941.598,00/tahun atau sekitar Rp 75.703.715,43/ha/tahun. Nilai ekonomi total diperoleh dari nilai pada sektor perikanan, nilai sirup dan sabun mangrove, nilai penjualan bibit mangrove, nilai ekowisata mangrove, nilai ekosistem mangrove sebagai penahan abrasi, nilai keanekaragaman hayati dan nilai keberadaan ekosistem mangrove. Analisis model dinamik menunjukkan bahwa peningkatan pemanfaatan luas hutan mangrove untuk ekowisata dan rehabilitasi akan berdampak pada meningkatnya nilai ekonomi total ekosistem mangrove. Analisis strategi pengelolaan yang tepat dilakukan di ekosistem mangrove Wonorejo yaitu konservasi hutan mangrove yang dianggap sebagai strategi pengelolaan yang berkelanjutan.
Keyword: analisis sistem dinamik, ekosistem mangrove, nilai ekonomi total, pengelolaan berkelanjutan, rehabilitasi

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