Judul: Forecasting the Gross Regional Domestic Product with the Approachment of ARIMA, Space Time, and Generalized Space Time Model
Abstrak: Model autoregressive integrated moving average (ARIMA) merupakan salah satu pendekatan yang sering digunakan dalam menganalisis data deret waktu. Seiring berkembangnya ilmu pengetahuan, diperkenalkan kelas model yang dapat memodelkan data deret waktu yang memiliki keterkaitan antar lokasi, yakni space time autoregressive (STAR) dan generalized space time autoregressive (GSTAR). Tujuan penelitian ini adalah mencari model peramalan terbaik produk domestik regional bruto (PDRB) berdasarkan pendekatan ARIMA, space time, dan generalized space time. Data yang digunakan adalah nilai PDRB berdasarkan pendekatan pengeluaran di provinsi DKI Jakarta, Jawa Barat, dan Jawa Timur. Hasilnya menunjukkan berturut-turut model ARIMA untuk provinsi DKI Jakarta, Jawa Barat, dan Jawa Timur adalah ARIMA(0,2,2), ARIMA(1,2,0), dan ARIMA(2,2,0). Selanjutnya, model space time dan generalized space time yang dapat memodelkan ketiga provinsi tersebut, diantaranya STMA(21), STAR(11), STAR(21), GSTMA(21), GSTAR(11), dan GSTAR(21). Berdasarkan nilai root mean square error (RMSE) terkecil, diperoleh bahwa model GSTAR(21) memiliki ketepatan yang paling baik pada peramalan nilai PDRB dua periode berikutnya.
Keyword: Institut Pertanian Bogor, Bogor Agricultural University, IPB, ARIMA, Generalized space time, RMSE, Space time, RMSE, Model peramalan, Pemodelan ARIMA, Model terbaik

Judul: Pengembangan Model Peramalan Harga Beras di Pulau Sumatera dengan Menggunakan Model Generalized Space Time ARIMA.
Abstrak: Model generalized space time autoregressive integrated moving average (GSTARIMA) merupakan model data deret waktu peubah ganda yang mempunyai keterkaitan lokasi dan waktu (space time). Model GSTARIMA merupakan pengembangan dari model space time autoregressive integrated moving average (STARIMA) dengan asumsi parameter-parameter model berbeda untuk setiap lokasi sehingga model GSTARIMA lebih fleksibel dibandingkan model STARIMA. Tujuan penelitian ini adalah menentukan model terbaik dan meramalkan data deret waktu harga beras pada seluruh ibukota provinsi di Pulau Sumatera dengan menggunakan model GSTARIMA. Data yang digunakan adalah data mingguan harga beras seluruh ibukota provinsi di Pulau Sumatera periode Januari 2010 sampai Desember 2017. Pembobot yang digunakan dalam penelitian ini yaitu bobot kebalikan jarak dan bobot queen contiguity. Hasil pemodelan menunjukkan bahwa model terbaik adalah model GSTARIMA (1,1,0) dengan matriks pembobot queen contiguity yang mempunyai nilai mean absolute percentage error (MAPE) terkecil yaitu sebesar 1.17817 %.
Keyword: GSTARIMA, kebalikan jarak, MAPE, queen contiguity, space time

Judul: Hybrid solar cells of ZnO nanoparticles/chlorophyll was modified metal ions (Zn2+ and Cu2+ )
Abstrak: Zinc Oxide (ZnO) is a n-type semiconductor with a wide the energy band (Band Gap) is 3.37 eV at room temperature and 3.34 eV at low temperature with a large exiton binding energy is 60 meV. ZnO has been synthesized by hydrothermal method, resulting in a decrease in particle size over the duration of the hydrothermal changes. Crystallographic structure of ZnO were characterized using XRD, has shown the characteristic pattern of a hexagonal wurtzite structure, the crystallite size increases to changes in particle size. Changes in particle size has also led to a change in the absorption peak of ZnO as has been demonstrated posted under test using the optical properties of UV-Vis spectrophotometer. Changes of this uptake has also led to changes in the energy band gap, which increases its band gap energy of the particle size. In electronic applications, especially in solar cells. Chlorophyll is considered less effective, because of their very nature are easily degraded as a result of several reactions which are acid, lighting and temperature. The results of the stability test using a halogen lamp 34 W/m2 for 5 hours, that the substitution of chlorophyll with metal ions Zn2+ and Cu2+ has been shown to form more stable than natural chlorophyll. The characterization of the optical properties, the combination of ZnO / chlorophyll in the form of hybrid films has led to a shift in the absorption region of ZnO becomes more widely from the UV to Visible. ZnO/chlorophyll has absorption range of 350-515 nm, ZnO / Zn-feofitin 332-401 nm and 332-632 nm for Cu-feofitin. The combination of ZnO/chlorophyll and CuSCN as a solid electrolite in hybrid solar cell, a modified chlorophyll with metal ions Zn2+ and Cu2+ has been shown to form a more stable I-V curve. It is characterized by its fill factor value greater than natural chlorophyll. Nevertheless, solar cells with natural chlorophyll has been able to produce higher efficiency values of chlorophyll were substituted.
Keyword: Hydrothermal, ZnO/Chlorophyll modified, Hybrid Solar Cell