Judul: Study on the Impact of Monsoon and EL-Nino Southern Oscillation (ENSO) on the Rainfall in Aceh
Abstrak: Iklim dan cuaca di Indonesia dibentuk oleh berbagai fenomena, baik fenomena yang berasal dari luar maupun dari dalam wilayah Indonesia. Beberapa fenomena yang mempengaruhi wilayah Indonesia tersebut ialah monsun dan El-Nino (McBride, 1992). Daerah Istimewa Aceh yang terletak di ujung Indonesia bagian utara dan barat tidak terlepas dari pengaruh monsun dan El-Nino. Namun pengaruh monsun dan El-Nino terhadap curah hujan di Aceh belum banyak diketahui, sehingga diperlukan penelitian untuk melihat pengaruh tersebut. Penelitian ini bertujuan untuk mengetahui pengaruh monsun dan El-Nino terhadap curah hujan di Aceh. Metode yang digunakan dalam penelitian ini ialah rata-rata, simpangan, koefisien korelasi, koefisien keragaman, dan uji F, yang ditampilkan dalam bentuk grafik maupun tabel, untuk menerangkan pengaruh monsun dan El-Nino tersebut. Hasil penelitian ini menunjukkan bahwa Aceh merupakan wilayah yang memiliki dua puncak hujan, yaitu pada bulan April dan Oktober. Hal tersebut dipengaruhi letak wilayah Aceh yang berada di dekat ekuator. Monsun juga mempengaruhi curah hujan di Aceh. Pengaruh monsun ini lebih besar di Aceh bagian utara, yaitu di Stasiun Blang Bintang dan Sabang Meteo. Berdasarkan data curah hujan di kedua stasiun tersebut, pada saat Monsun Timur Laut, curah hujan di Aceh melebihi rata-rata curah hujan bulanannya, sedangkan ketika terjadi Monsun Barat Daya, curah hujan di Aceh dibawah rata- rata curah hujan bulanannya. El-Nino kurang mempengaruhi curah hujan di Aceh. Pengaruh El-Nino tersebut terlihat pada bulan Juli-Agustus (Monsun Barat Daya) dan bulan Desember-Februari (Monsun Timur Laut).
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Judul: El Niño Modoki dan Pengaruhnya Terhadap Perilaku Curah Hujan Monsunal di Indonesia
Abstrak: This study aims to investigate El Niño Modoki phenomenon and its influence to the monsoonal rainfall behavior over Indonesia. The study is also intended to identify the differences between the El Nino Modoki and the well-known El Nino events, referred in this study as Conventional El Niño. By using correlation analysis, it is shown that the El Nino Modoki Index, known as EMI, is strongly correlated with SST anomaly index in Nino-4 region. The correlation coefficient value is 0.57, which is higher than the EMI’s correlations with other SST anomaly indices from different Nino regions, i.e. Nino-1.2, Nino-3 and Nino-4. Temporal analysis on both Nino-4 index and EMI by using Power Spectral Density shows a different strength in the temporal cycle of both indices, where Nino-4 data demonstrates a strong 4-5 year interannual cycles, while EMI is dominated by 6–8 years cycles. This is consistent with the result of Wavelet analysis that indicates four years interannual cycles of Nino-4 index and nearly decadal (~10 years) cycles of EMI data. The composite of seven El Nino Modoki events in 1986/87, 1990/91, 1992/93, 1994/95, 2002/2003, 2004/2005, and 2009/2010, generally shows that the El Nino Modoki events indicated by the raise of EMI exceeding its defined threshold usually occurred from July to March. It is shown by clear characteristics of growing phase starting from March or April until January, and continued by decreasing phase around February. Based on the results of regression analysis, the El Nino Modoki strongly influence monsoonal rainfall over Sumbawa Besar, Makassar, and Banjar Baru during both June-July-August (JJA) and September-October-November (SON) periods, over Lampung only during JJA, and Indramayu during SON. The use of EMI which includes information about the SST anomaly around Indonesia led to a significant cross-correlation values between monsoonal rainfall anomaly and EMI with only maximum of one month lag time.
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Judul: Construction of Strongly Optimal Binary Linear Code with Minimum Distance 9 and 11
Abstrak: A binary linear code of length n over q F is a subspace of n q F . A code has three parameters that attached to it, namely length, dimension, and minimum distance. A code with length n, dimension k and minimum distance d is often called [n, k, d ]-code. Usually, when two parameters are given, then we want to find a code that has the best value for the last parameter. Based on Gilbert- Varshamov bound, if a [n, k, d ]-code exists and can not be expanded, we call it a strongly optimal code. In this paper, we construct strongly optimal code with minimum distance 9 and 11. In constructing the code, we created a theorem and algorithm based on Gilbert-Varshamov bound before we implement the algorithm to MAPLE programming language. Because of computational limitations, the program can only construct up to k = 10 for d = 9 and k = 12 for d = 11.
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