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: Identifikasi Kawanan Ikan Pelagis Di Perairan Kabupaten Bintan dengan Menggunakan Deskriptor Hidroakustik
Abstrak: Upaya peningkatan akurasi data dan metode survei yang sesuai diperlukan untuk menjamin ketepatan sasaran pendugaan stok ikan. Salah satu metode yang mampu mengestimasi pendugaan stok perikanan secara handal adalah hidroakustik. Namun, identifikasi kawanan ikan di perairan Indonesia yang dihuni oleh spesies yang heterogen cenderung riskan dan rawan dilakukan karena kekhawatiran terjadinya kerancuan saat identifikasi. Sehingga dibutuhkan metode dengan akurasi tinggi agar tidak menimbulkan bias pada saat identifikasi. Penelitian ini bertujuan mengidentifikasi kawanan ikan dengan metode hidroakustik melalui pendekatan analisis statistika. Hasil yang diperoleh yaitu 42 kawanan ikan pelagis, hasil tangkapan yang diperoleh mayoritas jenis ikan pelagis kecil yaitu teri/bilis, sotong, tamban, dan parang. Variabel deskriptor yang menjadi penentu dalam proses identifikasi Schooling ikan adalah deskriptor energetik meliputi variabel TS, SV. Arus yang mengarah dari utara Pulau Tarempa menuju perairan timur Pulau Bintan melewati daerah sejajar pantai yang membawa banyak nutrien menuju perairan bagian timur pulau Bintan menyebabkan banyaknya kawanan ikan yang ditemukan pada bagian perairan tersebut. Deskriptor akustik dapat dijadikan sebagai metode dasar dalam mengidentifikasi kawanan ikan
Keyword: Deskriptor, Hidroakustik, Perairan Bintan, Schooling ikan

Judul: Pengelolaan Kebun Bibit Dalam Rangka Memenuhi Kebutuhan Bibit Tebu Giling
Abstrak: Tebu (Saccharum officinarum L.) termasuk tanaman tropika yang diusahakan untuk menghasilkan produk berupa gula. Tanaman ini merupakan penghasil gula terpenting. Menurut Wilsie (1962) kira-kira 60 persen dari produksi gula dunia berasal dari tebu dan 40 persen lagi dari gula bit. Ditinjau dari segi energi yang dibutuhkan manusia, gula merupakan sumber energi yang paling penting. Dari 100 gram gula pasir dapat dihasilkan energi sebesar 387 gram kalori, lebih tinggi daripada kalori yang dikandung beras giling dan jagung, masing-masing 360 dan 369 gram kalori (FAO dalam Notoyoewono, 1960). Saat ini produksi gula Indonesia belum mampu mencukupi kebutuhan gula dalam negeri yang semakin meningkat. Peningkatan konsumsi gula sebanding dengan meningkatnya jumlah penduduk, bertambahnya pendapatan per kapita serta meningkatnya pola konsumsi masyarakat (Kartasasmita, 1980). Apabila pertumbuhan GNP diperkirakan 7.5 persen per tahun dan income elasticity sama dengan 0.8 persen, maka kenaikan konsumsi gula tiap tahun sebesar 6 persen. Dengan tingkat pertambahan penduduk 2.2 persen, konsumsi gula pada tahun 1985 akan berjumlah 1 880 000 ton atau 13.1 kg per kapita (Kartasasmita, 1980). Oleh karena produksi dalam negeri hanya berkisar satu juta ton, maka perlu adanya langkah-langkah kebijaksanaan.
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