Judul: Distribusi, Kelimpahan dan Variasi Morfologis serta Makanan Bintang Laut (Protoreaster nodosus) di Perairan Waleo dan Bunaken Sulawesi Utara
Abstrak: Penelitian ini dilakukan untuk mengetahui hubungan antara karakteristik habitat dan biologi bintang laut P. nodosus, pola distribusi, kelimpahan, variasi morfologis, makanan dan kebiasaan makan. Pengukuran kondisi fisika-kimia perairan dilakukan bersamaan dengan waktu pengambilan sampel bintang laut. Tekstur substrat dianalisis di laboratorium Morfologi Pantai dan Hidro-Oseanografi Fakultas Perikanan dan Ilmu Kelautan Unsrat Manado, dengan menggunakan metode pengayakan. Untuk mengetahui pola distribusi dan kelimpahan bintang laut dilakukan metode transek, dengan ukuran kuadran adalah 1 x 1 meter sebanyak 10 buah pada tiap sub-stasiun dengan penempatan secara beraturan. Di lokasi penelitian dilakukan penimbanmgan bobot tubuh dan pengukuran terhadap panjang lengan, tebal cakram dari tiap individu sampel, serta pengamatan variasi warna. Untuk analisis makanan digunakan 30 individu pada tiap lokasi, sedangkan untuk mengetahui aktifitas makan dilakukan pengambilan 2 individu pada tiap interval waktu 2 jam selama 24 jam. Isi lambung tersebut diamati di Laboratorium Bioteknologi Kelautan dan Biologi Kelautan Fakultas Perikanan dan Ilmu Kelautan serta Laboratorium Dasar Unsrat Manado., This research has been conducted in the Waleo and Bunaken waters of North Sulawesi from May to August 2000. The purpose of this study is to investigate the correlation between habitat and biological characteristics i.e. distribution path, abundance, morphological characteristics, feeding preference and habits. The method used to know the distribution and abundance was the transect method, 1x1m in size. Each location was represented by 3 stations. thirty starfishes where used to analyze stomach content. Feeding activity was observed from each 2 individuals at 2 hours interval for 24 hours. The correlations between habitat and biological characteristics of P. nodosus were analyzed by the Primary Component Analyses. The distribution path by the Index of Morisita analyses, folowed by the khi-kudrat test and by t-test for abundance. Stomach content was analyzed by the Index of Preponderance and Index of Electivity. The distribution of both small and medium size of P. nodosus was characterized by coarse sand and high temperature, low salinity and slow current speed. While those of the large size of P. nodosus was characterized by fine sand, high salinity, disolved oxygen, low coarse sand and strong current speed. The large size of P. nodosus have higher weigh of seagrass in their stomach than those of the small and medium sizes of P. nodosus. The distribution path of starfishes in two locations of research was a typical cluster. The highest abundance has been found in the waters of South Waleo (20 starfishes), and South Bunaken (17 starfishes). The length of starfish's arms is about 7.8-12 cm, 174.4-379.1 grams in weight, and 1.8-4 cm in height. The result of stomach content analyses showed that the seagrass has the highest percentage in the stomach. Food items wich were positively choosen were T. Hemprichii, C. serrulata and E. acoroides. The feeding time of starfish is at day time (06:00 18:00 hours)
Keyword: Asteroidea, Distribution, Abundance, Morphological characteristic, Feeding preference

Judul: Taksonomi dan Habitat Pilihan Bintang Laut di Perairan Pulau Hari, Sulawesi Tenggara
Abstrak: Organisms prefer habitats which provide most of their requirement for growing and populating. In order to minimize competition, each population develops habitat sharing in many ways including diet preference and habit, and defense mechanism. This habitat sharing is demonstrated as area that is inhabited by individuals of the population. Research in habitat sharing of seastars has been conducted in August-December 2012. Seastar specimens were collected from and observed at Hari Island Waters (South East Sulawesi), applying road sampling and free handpicking technique. Geography position of each individu of seastar was remarked in GPS (Geographical Position System), and the characteristics of area where each individu of seastars was found, growth type and cover area of corals, species and cover area of seagrass, type of the substrate, was recorded. These position of seastars were then overlayed on habitat map to develop area inhabiting by each population of seastars. Results of research uncovered nine species of seastars that taxonomically confirmed: Linckia laevigata (Linnaeus, 1758) (Ophidiasteridae: Valvatida), Linckia multifora (Lamark, 1816) (Ophidiasteridae: Valvatida), Nardoa tuberculata Gray, 1840 (Ophidiasteridae: Valvatida), Nardoa novaecaledoniae (Perrier, 1875) (Ophidiasteridae: Valvatida), Fromia monilis (Perrier, 1869) (Goniasteridae: Valvatida), Culcita novaeguineae Műller & Troschel, 1842 (Oreasteridae: Valvatida), Choriaster granulatus Lütken, 1869 (Oreasteridae: Valvatida), Echinaster luzonicus Gray, 1840 (Echinasteridae: Spinulosida), Acanthaster planci (Linnaeus, 1758) (Acanthasteridae: Spinulosida). Corals grew well surrounding Hari Island, especially in the north side encircling a 2.9 ha lagoon. Between lagoon and the island, there were seagrass area (± 0.4 ha) and open sandy area. Most seastars inhabited this area, giving a distribution of west-east-direction belt. L. laevigata was found with the largest number of individuals (58 ind.), distributing widely. The habitat preference did not show specific. N. tuberculata prefered area with branching corals while C. novaeguineae tended to live in sandy area both among seagrass and corals. A. planci as coral feeders prefered tubulate Acropora eventhough some individuals found on massive coral and sandy bottom among corals. C. granulatus were found in a small area of sandy bottom among coral closed to reef slope. F. monilis and N. novaecaledoniae were only found 3 and 2 individuals, distantly each other, inhabiting close to reef slope. These two species have never been reported in large number. Habitat prefered by each population of seastars which showed in spatial distribution map, demonstrated a strategy in minimizing competition among populations. This strategy concerned with live requirement and adaptation potential (morphology and habits) of each seastar species.
Keyword: Seastars, prefered habitat, taxonomy, habitat share, Hari island

Judul: Formulasi Algoritme Operasi Grup Jacobian Kurva Hyperelliptic ...
Abstrak: Dalam geometri aljabar, kurva hyperelliptic merupakan bentuk umum dari kurva elliptic. Kurva ini apabila dikenakan pada suatu lapangan berhingga akan membentuk suatu grup siklik. Pada kriptografi, khususnya enkripsi kunci publik, grup siklik yang dibangkitkan oleh kurva elliptic sudah banyak diteliti. Bahkan untuk kurva ini sudah memiliki standar oleh National Institute of Standard and Technology (NIST) Amerika. Sedangkan, untuk grup yang dibangkitkan oleh kurva hyperelliptic masih memiliki kekurangan dalam hal komputasinya. Tujuan dari penelitian ini adalah mengkonstruksi suatu lapangan berhingga pada , memilih kurva hyperelliptic atas lapangan hingga yang memenuhi kriteria keamanan untuk kriptografi, dan membuat formulasi operasi grup kurva hyperelliptic menggunakan algoritme Cantor. Dalam merekonstruksi lapangan hingga, terlebih dahulu tentukan dimensi dari lapangan hingga tersebut dan polinomial tak-teruraikan. Kemudian dipilih kurva hyperelliptic atas lapangan tersebut. Pada penelitian ini, kurva yang dipilih adalah = + + dengan lapangan hingga . Berdasarkan kurva yang dipilih, akan dibentuk suatu operasi grup dengan menggunakan algoritme Cantor, sehingga menjadi lebih aritmatik. Eksplorasi kurva hiperelliptic dilakukan untuk mengetahui keamanan dari kurva yang dipilih. Dengan menyusun algoritme operasi grup dari kurva yang dipilih, diperoleh perhitungan yang lebih aritmatik dan dapat diimplementasikan pada kriptografi kunci publik. Dari segi keamanan kurva telah memenuhi standar sehingga tahan terhadap serangan-serangan seperti Poligh-Hellman, Polard- , ataupun Frey-Ruck secara teorema.
Keyword: algoritme Cantor, kriptografi, kunci publik, kurva hyperelliptic, operasi grup