Judul: Pemodelan Curah Hujan dengan Model Fungsi Transfer Input Ganda
Abstrak: Floods are natural events that have erratic pattern. The time when floods occure are detectable, when we are able to forecast rainfall. The amount of rainfall is influenced by several factors, including temperature and humidity. Rainfall, temperature, and humidity are time series data that have are not independent. Forecasting for time series data can be done by using ARIMA model. Forecasting result from ARIMA models are not satisfying because it is not close to the actual data, which was also showed by its MAPE value of 37.01%. Hence the transfer function model was applied to forecast rainfall as the output variable along with temperature and humuidity factor as the input variable. The result from transfer function model used for short run forecasting (1 week) was quite good which can be seen by its MAPE value of 5.28%. Although transfer function model has a lower MAPE value compared to ARIMA model, transfer function model is not good enough to be used on long-term (1 month) rainfall forecasting, which is showed by its MAPE value of 31.68% and it could not detect flood occurence well. Based on those MAPE values it can be concluded that the transfer function model is still better than ARIMA model.
Keyword: Bogor Agricultural University (IPB), transfer function model, rainfall, ARIMA mode

Judul: Model fungsi transfer antara curah hujan dengan jenis dan liputan awan di sebagian Jawa Barat
Abstrak: Tujuan Penelitian ini adalah untuk menetapkan model yang menghubungkan deret besar curah hujan sebagai deret output dengan deret jenis dan liputan awan sebagai deret input dan dengan deret gangguan, kemudian mencoba menggunakannya untuk peramalan. Data yang digunakan dalam penelitian ini adalah data jenis dan prosentase liputan awan serta besar curah hujan untuk daerah 106° 107° Bujur Timur dan 7° Lintang Selatan dari bulan Januari 1982 sampai Juni 1986. Data Pertama diperoleh dari Stasiun Bumi Satelit Lingkungan dan Cuaca LAPAN Jakarta; dan data ke dua diperoleh dari Badan Meteorologi dan Geofisika Jakarta yang didukung oleh data yang diperoleh dari Dinas Pekerjaan Umum bagian Pengairan kabupaten Bogor, Tangerang, Serang dan Sukabumi. Penetapan model dilakukan dengan analisis deret waktu dengan menerapkan model fungsi transfer. Dalam hal ini, identifikasi model didasarkan kepada grafik fungsi korelasi silang antara deret input dengan deret output yang telah bersih gangguan, serta dengan memperhatikan grafik fungsi korelasi diri dan korelasi diri parsial deret ganggguan. Pendugaan parameter model dilakukan dengan metode kuadrat terkecil melalui cara pendugaan nonlinear.
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Judul: Extraction and Characteristic of Collagen and Nanoparticle Collagen from the Skin of Stingray Fish (Pastinachus solocirostris) as Ingredient of Cosmetics.
Abstrak: Isolation of collagen from the skin of stingray fish (Pastinachus solocirostris) has been successfully conducted with three stages: first soaked in 0.05 M NaOH with a sample/solution ratio of 1:10 (w/v) for 6 hour, second soaked in 0.1 M acetic acid with a sample/solution ratio of 1:6 (w/v) for 2 hour, and third extraction with destilated water at temperature 40 C for 2 hour with a yield of 14.475 % (wet base). Nanoparticle collagen was made with desolvation method using etanol as a desolvating agent with a collagen solution/etanol ratio of 1:1. Yield of nanoparticle collagen was 9.64% (wet base) with particle size of 185.24 nm. Collagen and nanoparticle collagen is in the form of white powder with whiteness degree 72.48% and 60.03%, respectively. Protein is the major component in collagen and nanoparticle collagen (86.97% and 86.18%) with trace amount of ash (0.17% and 0.13%) and fat (0.19% and 0.25%), respectively. Based on sodium dodecyl sulfate-polyacrylamide gel electrophoresis patterns, amino acid composition, and fourier transform infrared (FTIR) spectra of both collagen and nanoparticle collagen were characterized as type I collagens. Nanostructural analysis of collagen and nanoparticle collagen by Scanning Electron Microscopy (SEM) shows that both were separate aggregates. Other characteristics of collagen and nanoparticle collagen were: Tmax of 165.88 C and 156.63 C; Viscosity 292.33 cP dan 110 cP; pH 5.00 dan 4.93; respectively. Collagen has highest solubility at pH 7 and the isoelectric point at pH 6, 9, and 10. Therefore, nanoparticle collagen has highest solubility at pH 3 dan and the isoelectric point at pH 6. Collagen and nanoparticle collagen from skin of stingray fish (Pastinachus solocirostris) has a characteristic for a potential use as a cosmetic ingredient.
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