Forecasting wind speed data by using a combination of ARIMA model with single exponential smoothing

Wind serves as natural resources as the solution to minimize global warming and has been commonly used to produce electricity. Because of their uncontrollable wind characteristics, wind speed forecasting is considered one of the best challenges in developing power generation. The Autoregressive Integrated Moving Average (ARIMA), Simple Exponential Smoothing (SES) and a hybrid model combination of ARIMA and SES will be used in this study to predict the wind speed. The mean absolute percentage error (MAPE) and the root mean square error (RMSE) are used as measurement of efficiency. The hybrid model provides a positive outcome for predicting wind speed compare to the single model of ARIMA and SES

The Use of Rasch Measurement Model in English Testing

This study aimed at determining the quality of the English Paper 1 (EP1) items of UPSR trial examination for six graders in terms of its reliability, validity and items characteristics. It also sought to determine the difficulty levels of 40 multiple-choice items consisting five constructs of vocabulary, language and social expression, grammar, cloze-comprehension and reading comprehension. A number of 525 primary schools students were randomly selected from 3876 students in Kuala Selangor, Malaysia. Using the Rasch measurement model, the validity evidences were shown through the results of Principle Component Analysis (PCA), fit statistics and item distractor analysis. The results from PCA analysis showed the absence of second dimension in the test, which met the assumption of modern testing theory. Fit statistics analyses have identified seven misfit items that are beyond the acceptable range (0.7 - 1.3 logit). Item distractor analysis has identified five problematic items whereby three of them are also misfit items. Summary statistics shows that the reliability indices of Cronbach's Alpha were greater than 0.80 and separation indices were greater than 2. This study would benefit teachers in improving existing assessment practice by spreading out the importance of item analysis in schools, particularly in language testing

Experimental Study of TiO2 Nanoparticles Fabrication by Sol-gel and Co-precipitation Methods for TiO2/SnO2 Composite Thin Film as Photoanode

Sol-gel and coprecipitation methods successfully prepared titanium dioxide (TiO2) powders with anatase structure. The TiO2 powders are then used to fabricate pure TiO2 thin-film or mixed with SnO2 powders for the TiO2/SnO2 composite thin film. Furthermore, the structural, morphological, as well as the optical properties of films were also investigated. The results showed that the synthesized thin-film of TiO2 powders by sol-gel method obtained better crystallinity and microstructure compared to the synthesized thin film by co-precipitation method. In the DSSC system, these features are needed to increase the electron mobility that responsibility for transport and recombination of photoexcited electrons. SEM images exhibited the smooth surface and uniform in particle size obtained by the addition of SnO2 powders in composite films. The composite thin film also indicated a higher transmittance value. Keywords: sol-gel,co-precipitation,anatase, composite

Pengaruh Good Governance, Gaya Kepemimpinan, Komitmen Organisasi dan Budaya Organisasi terhadap Kinerja Pemerintah Daerah (Studi pada Pemerintah Daerah Kabupaten Kampar)

This study aims to examine the effect of good governance, leadership style, organizational commitment and organizational culture on the performance of local government in District Government of Kampar. The research samples are selected by using questionnaire survey method were 18 manager in the special district of Kampar. The analytical tool used is multiple regression. The result showed show that: (1) good governance has positive influence on the performance of local government, (2) leadership style has positive influence on the performance of local government (3) organizational commitment has positive influence on the performance of local government (4) organizational culture does not affect the performance of local government.Keywords: Good governance, leadership style, organizational commitment and Organizational culture, performance of local governmen

Pemilihan Teknologi Produksi Hidrogen dengan Memanfaatkan Energi Nuklir

PEMILIHAN TEKNOLOGI PRODUKSI HIDROGEN DENGAN MEMANFAATKAN ENERGI NUKLIR. PLTN digunakan untuk pembangkit listrik maupun sebagai sumber panas untuk aplikasi non-listrik (kogenerasi). Reaktor Suhu Tinggi (RST) dengan suhu pendingin keluar reaktor 900~10000C, merupakan jenis reaktor nuklir yang berpotensi untuk tujuan kogenerasi, seperti : produksi hidrogen dan proses industri kimia lain yang memerlukan panas tinggi. Terkait dengan Kebijakan Energi Nasional, bahwa di masa depan harus mengatur keseimbangan sumber daya alam terbarukan dan yang tidak terbarukan, dengan menjaga sebaik-baiknya kelestarian alam sampai batas maksimal untuk sebesar-besarnya kemakmuran rakyat, maka produksi gas hidrogen menggunakan energi dari PLTN merupakan pilihan yang tepat. Gas hidrogen merupakan energi baru yang ramah lingkungan dan sumber energi alternatif yang mempunyai prospek di masa mendatang. Pada kajian ini tiga proses produksi hidrogen menggunakan energi nuklir yaitu elektrolisis, steam reforming dan termokimia siklus sulfur-iodine telah dibandingkan. Parameter yang diperhitungkan meliputi : biaya produksi, biaya modal, biaya energi, status teknologi, ketidak tergantungan pada bahan bakar fosil, keramahan terhadap lingkungan, efisiensi dan ketidak tergantungan pada material tahan korosi. Hasil studi menunjukkan bahwa teknologi produksi steam reforming lebih unggul dibanding elektrolisis dan siklus sulfur-iodine, sehingga teknologi steam reforming lebih menjadi pilihan untuk produksi hidrogen dengan memanfaatkan energi nuklir di Indonesia