Judul: Kajian kandungan nitrogen pada kolom perairan dan sedimen akibat aktivitas karamba jaring apung di Waduk Cirata, Jawa Barat
Abstrak: Penelitian bertujuan untuk mengkaji kandungan nitrogen di perairan dan di dasar sedimen, yang diakibatkan oleh aktivitas Karamba Jaring Apung (KJA). Penelitian dilakukan di Waduk Cirata dari bulan Juli sampai September tahun 2006. Terdapat empat stasiun pengamatan yaitu; inlet waduk (stasiun I), daerah KJA sedang (stasiun 2), daerah KJA padat (stasiun 3), clan outlet waduk (stasiun 4). Terdapat dua jenis sampel yang diambil yaitu sampel air dan sampel sedimen. Sampel air diambil secara vertikal di setiap stasiun pada interval 10 meter (0 m, 10 m, 20 m, 30 m) dan kedalaman dekat dasar (interface). Sampel sedimen diambil satu kali pada setiap stasiun. Nitrogen yang diteliti pada penelitian ini antara lain; ammonia total (NH3 dan NH4+), nitrit(NO2-), nitrat (NO3-), nitrogen total (untuk nitrogen di perairan), ammonium (NH4-), nitrat (NO3-), nitrogen total (untuk nitrogen di sedimen). Analisis statistik untuk nitrogen di perairan menggunakan Rancangan Petak Terbagi (Split Plot Design), untuk nitrogen di sedimen menggunakan Rancangan Acak Kelompok (RAK), dan uji lanjut Beda Nyata Terkecil (BNT).
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Judul: Kandungan P dan H2S pada keramba jaring apung di Waduk Cirata, Jawa Barat
Abstrak: Penelitian ini bertujuan untuk mengetahui kandungan P (Total Fosfor dan Ortofosfat) serta H₂S (Hidrogen Sulfida) sebagai limbah hasil buangan keramba jaring apung pada perairan eutrof, Waduk Cirata. Penelitian dilaksanakan bulan Mei sampai Juli 2005 di KJA Babakan Garut, Perairan Jangari, dan daerah Outlet Waduk Cirata. Pengukuran parameter kualitas air tersebut dilaksanakan sebanyak tiga kali pengamatan dengan selang waktu tiga minggu dengan cara mengambil sampel air dari tiga stasiun kemudian dianalisa di laboratorium. Kondisi lingkungan di KJA yang meliputi kedalaman mengalami penurunan setiap bulan dan memasuki musim kemarau. Parameter yang diamati meliputi Total Fosfor, Ortofosfat, H₂S serta parameter fisika dan kimia perairan Waduk Cirata yaitu parameter fisika (suhu, kecerahan, kekeruhan dan TSS) dan parameter kimia (pH, alkalinitas, DO, BOD, dan CO2). Hasil pengamatan terhadap parameter lingkungan cukup berfluktuasi setiap bulannya yaitu nilai total fosfor di Waduk Cirata berkisar antara 0,0256 mg/l sampai 0,4125 mg/l, ortofosfat 0,0016 mg/l sampai 0,1354 mg/l, H₂S di 0,00125 mg/l sampai 0,0576 mg/l. fluktuasi harian suhu bulan Mei terjadi stratifikasi yang memiliki pola clinograde, kecerahan sedang, perairan cukup keruh, TSS relatif tinggi, pH stabil, oksigen terlarut relatif stabil, Total P sedang, Ortofosfat sedang dan H₂S melebihi batas ambang dalam budidaya ikan di KJA. Hal ini sangat berpengaruh terhadap laju pertumbuhan ikan mas dan nila yang umum dibudidayakan di tiap KJA. Adanya penumpukan sisa pakan dan hasil metabolisme ikan di dasar perairan akan mengakibatkan perubahan kualitas air dan jika terjadi umbalan akan mematikan ikan-ikan budidaya yang terjadi setiap menjelang perubahan musim terutama dari musim kemarau ke musim penghujan.
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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