Judul: Metode Steepest Descent Dalam Pengoptimuman Fungsi Dan Penerapannya Menggunakan Aplikasi Android
Abstrak: Pengoptimuman bertujuan mencari nilai minimum atau maksimum dari suatu fungsi bernilai real. Dari segi fungsinya, pengoptimuman dapat dibedakan menjadi pengoptimuman linear dan pengoptimuman nonlinear. Sedangkan dari segi bentuknya, pengoptimuman dikelompokkan menjadi pengoptimuman berkendala dan pengoptimuman tak berkendala. Untuk menyelesaikan permasalahan pengoptimuman tak berkendala, khususnya untuk fungsi nonlinear, dapat digunakan metode steepest descent. Metode ini adalah metode iteratif untuk memperoleh solusi pendekatan dari masalah awal. Karya ilmiah ini mengkaji metode steepest descent dan kemudian menerapkannya dalam aplikasi Android Studio 1.0.1 dengan mencari titik minimum dari fungsi kuadratik dengan konstanta tertentu. Dalam karya ilmiah ini diperoleh kesimpulan bahwa hasil iterasi tidak hanya dipengaruhi oleh banyaknya variabel yang digunakan dan besarnya toleransi, namun juga dipengaruhi oleh nilai fungsi.
Keyword: Android studio, Metode steepest descent, Pengoptimuman

Judul: Metode Gradien Konjugat Dalam Menyelesaikan Masalah Optimasi Menggunakan Aplikasi Android
Abstrak: Pengoptimuman bertujuan mencari penyelesaian terbaik dari suatu masalah. Terdapat beberapa metode untuk menyelesaikan masalah pengoptimuman dengan kelebihan dan kekurangan yang berbeda untuk masing-masing metode. Salah satu metode yang sering digunakan untuk menyelesaikan masalah pengoptimuman takberkendala, khususnya untuk fungsi taklinear adalah metode gradien konjugat. Karya ilmiah ini membandingkan waktu penyelesaian dan banyaknya iterasi untuk metode gradien konjugat Fletcher-Reeves, Polak-Ribere-Polyak, Hestenes-Stiefel, dan Dai-Yuan dalam menyelesaikan suatu permasalahan pengoptimuman tanpa kendala untuk kasus fungsi kuadratik. Hasil numerik yang diperoleh menunjukkan bahwa metode gradien konjugat Hestenes-Stiefel dapat menyelesaikan suatu pengoptimuman dengan waktu yang lebih cepat dan menemukan titik optimum dengan iterasi yang lebih sedikit dibandingkan dengan metode gradien konjugat lainnya.
Keyword: Metode gradien konjugat, Pengoptimuman, Android

Judul: Phylogeography and Species Limits in the Papuan White Snake (Micropechis ikaheka) (Reptilia: Serpentes: Elapidae)
Abstrak: Papua white snake, Micropechis ikaheka, has been distingushed into two subspecies M.i. ikaheka and M.i. fasciatus. However, due to lack of data on their morphology, distribution and ecology, both subspecies often ignored in scintific discussions and refers only byas , Micropechis ikaheka. This study was designed to document the differences between M.i. ikaheka and M.i fasciatus by using scales characteristics and reproductive organ or hemipenes. The study also examine, zoogeography, habitat, diet and cannibalism of both subspecies to better understanding the the ecology of one of the most venomous snakes in the world. This study consists of three topics with method and also different in the size samples, respectively. The first study is the histology and microtopography of the skin were studied using paraffin method and Scanning Electron Microscope (SEM). The second is the hemipenis were examined by following Myers and Cadle (2003), and Zaher and Prudente (2003). The third is the abdominal surgery was carried out to document diet type and the investigate phenomenon of cannibalism in the snake. Specimens for this study came from the collection from Museum Zoologicum Bogoriense (MZB) and Universitas Negeri Papua’s Laboratory (LZU). The research result also indicated that the markers of skin and hemipenis described the same structure and microornamentation in all M. ikaheka groups being compared. Based specimens examined morphological descriptions do not s support the further differentiation in Micropechis. In short, two markers that used in this study could not sufficiently indicate the differences in the level of species and subspecies of M. ikaheka. The study, however, were able to delineate zoogeography and skin color patterns, which fall into four groups: M. i. ikaheka; M. i. fasciatus. M. i. ssp. “intermediate”; and M. i. ssp “black”. This study also revealed that color variations did not overlap in their geographic distribution. It is therefore, it suggested that environmental factors may contribute to the skin color variations. It also assumed that habitat discontinuous and biogeography factors may also cause the loss of the connection between the original populations (vicarians) or follow colonization events (dispersal). The examined of 22 stomach contents of M. ikaheka shows this species is carnivorous, and prey on vertebrates such as amphibians, fish, reptiles, and Mammals. These snakes are opportunistic predators since they prey on all that can be captured, but mainly reptiles (61.5%), followed by mammals and fish (both 15.4%), and amphibians (7.7%). Although categorized as terrestrial animal, the diet study showed that M. ikaheka snakes often go into the water to hunt for fish (the sample from Yapen island), including eel (the sample from Aru island). Based on prey items indentified, there is evidence that M. ikaheka is cannibal. At this time, there still no record on reason for cannibalism, but it is assumed that cannibalism was due to competition between populations and means to control population.
Keyword: geographic variation, white snake, papua