Judul: M-Estimation Using the Huber Weighting Function and the Tukey Bisquare
Abstrak: Keberadaan pencilan dapat memengaruhi pendugaan parameter dalam analisis regresi yang menggunakan metode kuadrat terkecil (MKT). Metode regresi kekar dapat digunakan sebagai alternatif pendekatan dari MKT. Penelitian ini dilakukan untuk mengkaji model regresi dengan metode jumlah kuadrat terkecil dan metode analisis regresi kekar yakni Estimasi-M dengan fungsi pembobot Huber dan Tukey melalui data bangkitan. Data bangkitan diperoleh dengan membangkitkan bilangan acak berdasarkan model regresi linear tanpa pencilan dan diberikan proporsi pencilan. Hasil yang diperoleh menunjukkan bahwa pembobot Tukey dan Huber pada data yang mengandung pencilan memiliki nilai Mean Square Error (MSE) yang lebih kecil dibandingkan dengan MKT. Hal ini menunjukkan bahwa pembobot Tukey dan Huber pada kasus penelitian ini bersifat lebih kekar daripada MKT. Dengan demikian metode Huber dan Tukey dapat digunakan untuk mengatasi gugus data yang mengandung pencilan., The existence of outliers can affect parameter estimation in regression analysis using the ordinary least squares method (OLS). The robust regression method can be used as an alternative approach to the OLS. This research was conducted to examine the regression model using the Least Squares method and the robust method with the Huber and Tukey weighting functions through the generation data. Generation data is obtained by generating random numbers based on a linear regression model with no outliers and given the proportion of outliers. The results obtained indicate that the Tukey and Huber weights on the data containing outliers have a smaller Mean Square Error (MSE) value than the OLS. This shows that the Tukey and Huber weights in the case of this study are more robust than the OLS. Thus, the Huber and Tukey method can be used to overcome clusters of data that contain outliers.
Keyword: pencilan, Estimasi-M, Metode kuadrat terkecil, analisis regresi, M-Estimation, ordinary least squares, regression analysis, outlier

Judul: Kajian Perbandingan Metode Least Median of Squares dan Maximum Likelihood Type pada Regresi Kekar
Abstrak: Keberadaan pencilan dapat memengaruhi pendugaan parameter dalam analisis regresi yang menggunakan metode ordinary least squares (OLS). Metode regresi kekar dapat digunakan sebagai pendekatan alternatif dari OLS. Penelitian ini dilakukan untuk mengkaji perbandingan dari dua metode regresi kekar, yaitu least median of squares (LMS) dan maximum likelihood type (M) melalui data simulasi. Data simulasi diperoleh dengan membangkitkan bilangan acak berdasarkan model regresi linear berganda dua peubah penjelas. Kombinasi yang digunakan adalah jenis pencilan, proporsi pencilan, dan ukuran contoh. Berdasarkan nilai bias mutlak dan kuadrat tengah galat (KTG) diperoleh bahwa metode M lebih tepat diterapkan ketika data mengandung vertical outlier atau good leverage point, lalu diikuti oleh metode LMS. Sementara itu, metode LMS dapat menduga parameter regresi pada data yang mengandung bad leverage point. Analisis selanjutnya dilakukan pada data pertanian mengenai pengaruh pupuk organik dan konsumsi beras per kapita terhadap produksi padi sawah di 34 provinsi tahun 2017. Hasil yang diperoleh menunjukkan bahwa metode LMS menghasilkan nilai bias mutlak dan KTG terkecil., The presence of outliers can be affect to estimate the parameters of the linear regression using ordinary least squares (OLS). The robust regression methods can be used as an alternative to OLS. This study aims to compare the performance of two methods, namely least median of squares (LMS) and maximum likelihood type (M) using simulation study. The simulation data obtained by generating random number based on multiple linear regression with two explanatory variables. With combination of the sample size, outliers type, and the number of outliers. Based on the criteria: absoulut bias and mean square error (MSE), the M-estimator gave better result than the LMS-estimator when the data contains vertical outliers or good leverage point. Meanwhile, the LMS-estimator gave better result at data containing bad leverage points. The next step is analysed data application for agriculture on the affect of organic fertilizer and rice consumption per capita against the use of rice production in 34 provinces in 2017 using the best method based on data characteristic. The results from LMS-estimator produce the smallest absolut bias and MSE.
Keyword: LMS, M, OLS, Outlier, Robust Regression

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