Judul: Analisis penentuan jenis kawanan ikan berdasarkan deteksi fasa pantulan gelombang akustik dan penerapan hidden markov model
Abstrak: The aim of this research was to show that detection of phase shifted of acoustic wave reflection due to the movement of the fish school could identify the kind of fish school or the moving targets from its properties. Using the Hidden Markov Model (HMM), the observed fish school could be recognized from other fish schools. The research were executed into three experiments, namely phase shifted detection simulation, interference simulation and in situ experiment. The phase shifted detection simulation was executed to prove that the waveform of phase shifted reflected acoustic wave of moving target could identify its characteristics based on its dimension, shape, speed and structure in a group that simulated by the number of imitation fishes. During experiment, the imitation fishes were pulled by electric motor with different speed and transducer positions toward the direction of imitation fish. The research also analyzed the influences of several kind of possible interferences generated during the phase detection of the acoustic wave reflection. The simulation were done by means of electronic circuitry that represented .the fishes wave reflection and by the interference waves such as the reflection wave, and the engine sound. In situ experiment were executed to observe the real condition of the phase shifted reflection wave for 3 (three) kind of fishes. The three kind of fishes, consist of schooling fish species, shoaling fish species and a solitary fishes species . The phase shifted data were collected from the experiments in the fishing pool in the Seaworld and in a 4x4 m sea cage in Genteng Island. In this research, the phase shifted wave of all kind of fishes and all kind of imitation fishes was be detected by the fish species detector using a phase shifted detection technique. To distinguish the kind of fishes or imitation fishes, the angle between two or more line slope of the spectrum envelope of each phase shifted waves were calculated. If the two lines were parallel or the angle between the lines were 0o, the spectrum or the phase shifted wave were coincide each other, or the two wave were the same and, if the two lines formed a certain angle, then such spectrums or phase shifted waves were different. Hidden Markov Model (HMM) technique was applied for recognition processing. Computational results, showed that the reflection wave of the schooling fishes could recognized the fish school accurately (the fish school were 100 % identified successfully), however such recognition processing was not valid for shoaling and solitary fishes. From the interference simulation results, the reflection wave due to the surrounding areas of the objects, engine noise, fish direction and transducer position were not affected the result of identification and recognition processes.
Keyword: Phase detection, Acoustic, Fish school recognition, Gerakan ikan, Sistim deteksi kawanan ikan

Judul: Deteksi Pergerakan Ikan Berdasarkan Perubahan Fase pada Metode Hidroakustik
Abstrak: Tingkah laku ikan seperti halnya gerakan ikan penting diketahui dalam metode penangkapan ikan dengan menggunakan alat tangkap tertentu. Metode yang efektif dan efisien untuk mendapatkan informasi mengenai sumberdaya ikan di suatu perairan adalah metode hidroakustik. Teknologi akustik dengan menggunakan perubahan fase adalah menentukan waktu tunda (delay) yang terjadi pada objek yang bergerak fluktuatif. Jika suatu gelombang merambat pada suatu media (air) dan dipantulkan oleh gerakan renang kawanan ikan (struktur gerombolan ikan tetap untuk satu jenis tertentu), maka gelombang yang dipantulkan tersebut akan mengalami perubahan fase pada setiap satuan waktu sesuai dengan bentuk atau struktur permukaan (morfologi ikan) dan kecepatan gerakan kawanan ikan yang dipantulkan tersebut Tujuan dari penelitian ini adalah untuk mengetahui pergerakan suatu kawanan ikan pelagis dari jenis Thunnus albacares dan Katsuwonus pelamis dengan mendeteksi fase gelombang pantul akustik. Pengolahan data data dilakukan dengan menggunakan program Wavelab 5.0; Microsoft Excel; Statistica 8; dan Surfer 8.0. Analisis data yang digunakan adalah analisis domain waktu dan analisis Fast Fourier Transform (FFT) Gerakan ikan dapat diketahui secara baik dengan menggunakan alat pendeteksi perubahan fase (shift phase detector) yaitu dengan menentukan jarak waktu yang diakibatkan oleh kecepatan atau laju renang ikan yang ditimbulkan oleh kecepatan sentakan ekor (tail beat rate), sehingga dapat membedakan kawanan ikan yang bergerak cepat dan kawanan ikan yang bergerak lambat Pergerakan ikan tidak terdeteksi secara baik atau alat pendeteksi perubahan fase sulit untuk membedakan pergerakan kawanan ikan yang tidak teratur atau pergerakan ikan yang berbeda arah pada masing-masing kelompoknya atau individu ikan itu sendiri, dan jika pergerakan kawanan ikan berada diluar beam yang dipancarkan transducer.
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Judul: Trichosanthes (Cucurbitaceae) In Malesia
Abstrak: Trichosanthes L. merupakan marga terbesar yang tergolong dalam suku Cucurbituceae. Marga tersebut beranggotakan sekitar 100 jenis, tersebar di Asia bagian timur, Malesia, Australia tropik sampai ke Fiji. Beberapa jenis anggotanya mempunyai nilai ekonomi sebagai bahan obat tradisional maupun sayuran, bahkan Cina telah mengembangkaa T. kirilowii, guna mendapatkan zat bioaktif yang dapat digunakan untuk menggugurkan kandungan bahkan sebagai bahan anti HIV.
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