Judul: Pengembangan Model Telekoneksi antara Kejadian El-Niño dengan IOD dan Pengaruhnya Terhadap Fluktuasi Curah Hujan di Daerah Sentra Produksi Pangan (Studi Kasus : Sukamandi dan Padang Panjang).
Abstrak: Geoss4th (Global Earth Observation System to System) Asia-Pacific Symposium, March 2010 in Bali, suggested that teleconnection between all the global climate data and their impacts to the rainfall variability over Indonesia, especially between SST Nino 3.4 and IOD when both phenomena come simultaneously in the same time is very important to be investigated comprehensively. Based on that suggestion, this paper objective is to develop a model that can explain how teleconnection between El-Niño and IOD influence rainfall fluctuation in Indonesia. Location that used in this paper are Sukamandi and Padang Panjang, those are food centre region in Indonesia. First point of this paper is short term analysis. Methods to accomplish the goal of this analysis are spectral analysis and cross correlation. The idea is to combine Anomaly SST Niño 3.4 with IOD (Niño 3.4+IOD) to form a new index that present teleconnection and then check the cross correlation between Niño 3.4+IOD and rainfall anomaly on two cities mentioned above. The result from cross correlation between those data are the response about teleconnection from those cities are different and also there is a lag time before teleconnection take effect to those cities. After the short term analysis is complete, which is analyze response of two cities to teleconnection, it was continued by long term analysis. The target of this analysis is to develop a model from Niño3.4+IOD, the model is used as a precursor when will the teleconnection will have a very bad effect to our climate. This analysis is done by using ARIMA (Autoregressive Integrated Moving Average) method. The result of this analysis is an ARIMA(p,d,q) equation that can predict until few next month, so preventive action can be taken to minimalise the impact of long wet season or long dry season
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Judul: Penerapan Model ARIMA untuk Prediksi Anomali Curah Hujan Berdasarkan Indeks Monsun dan El Niño di Beberapa Kawasan di Indonesia.
Abstrak: This study based on atmosphere-ocean interaction that is very important to be investigated because of its influences to the rainfall variability over Indonesia. This study aims to investigate Monsoon and Niño 3.4 interaction in influencing rainfall fluctuation over Indonesia. The study areas cover Lampung, Sumbawa Besar, Indramayu, Banjarbaru, and Pandeglang from Januari 1976 - Desember 2000. The results of Power Spectral Density (PSD) and Wavelet analysis on rainfall anomaly and monsoon index data show strong at 12 months. Dominant oscillation pattern of Niño 3.4 is about 60 months. The result of regression analyses shows more significant relation between rainfall anomaly and AUSMI (Australian Monsoon Index) and WNPMI (Western North Pacific Monsoon Index). Therefore, it is suggested that the Monsoon (AUSMI and WNPMI) and El-Niño(Niño 3.4) can be used for further analysis. This study was undertaken with assumption that Monsoon oscillation and El-Niño are interacted and the model is developed by using multivariate regression method: Y = a + bAUSMI + cWNPMI + dNiño3.4. By using Box-Jenkins method based on ARIMA (Autoregressive Integrated Moving Average), the prediction model that is close to observed time series data of rainfall anomaly is ARIMA (1,0,1)12 with model equation Zt = 0.9989Zt-12 - 0.9338at-12 + at (AUSMI), ARIMA (1,1,1)12 with model equation Zt = -0.0674Zt-12 + Zt-12 - Zt-24 - 0.9347at-12 + at,(WNPMI), dan ARIMA (2,0,2) with model equation Zt = 3.594Zt-1 -0.8362Zt-2 – 1.634at-1 - 0.1053at-2 + at (NINO3.4). Model equation shows that time series data forecast of rainfall anomaly depend on previous “t” months data and previous ”t” months error.
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Judul: Grup dan Homomorfisma Grup pada Rubik Revenge
Abstrak: Rubik cube is a kind of puzzle game. A player must arrange rubik sides, which have been disordered, back to the position where every side has the same colour. This paper does not focus on the settlement solution, but instead on proving the existence of a group homomorphism between rubik movement group and S96 symmetric permutation group in rubik revenge. Firstly, it has been proved that rubik movement set is a group. Then, it also has been proved that the M set, which contains numeric labels of 1 until 96 in cubinos sides, is S96 symmetric permutation group.
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