Judul: The Analyse of Oil Palm Productivity Prediction Using Anomaly of Sea Surface Temperature at Nino-3,4
Abstrak: Yield variability of oil palm (fresh fruit bunch, FFB) is determined by interaction between genetics, ages, environmental (soil and climate), and technical culture factors. Climate factor may explain most of the yield variability if other factors are not very variable. One of the main climate factors affecting the yield of palm oil in Indonesia is rainfall. This study was conducted to evaluate impact of rainfall variability on production of palm oil in 26 big plantations in Sumatra Island with assumption that conditions of non-climatic factors such as varieties (genetic), technical culture is relatively homogenous. As many studies suggest that rainfall variability in Indonesia is strongly influenced by ENSO phenomenon, we analyse the potential use of ENSO index (based on anomaly of sea surface temperature/ASST at Nino-3,4) to predict palm oil yield in the plantations. The prediction models was developed using a number of steps. First is to remove the effect of age and seasonality of palm oil yield from the data series using non linear equation and Fourier regression (called as detrended yield). Second is to develop relationship between the anomaly of the detrended yield and anomaly of ASST in region 3,4. Third is to construct model to predict palm oil production in the plantation using stochastic spreadsheet based on equations developed in the previous steps. The result of analysis showed that the non-linear function can explain well the relationship between yield and age. The model could explain between 60% and 90% of the variability of palm oil production across the 26 plantations. Furthermore, the study suggests that the ENSO impact on yield variability was only significant in seven plantations located in areas that have south moonsonal rainfall type (South part of Sumatra such as part of Jambi, Lampung and South Sumatra). It was found that the ASST in region 3,4 is potential to be used for predicting production of palm oil in the seven plantations. The result of validation showed that there is no significant different between observed and predicted data (tvalue < ttable; α=1%).
Keyword: 

Judul: Sensitivitas Produksi Kelapa Sawit (Elaeis guineensis Jacq.) Terhadap Variabilitas Curah Hujan Akibat Pengaruh Penyimpangan Iklim
Abstrak: The aims of this study is to assess the impact of ENSO (El Nino and Southern Oscillation) and IOD (Indian Ocean Dipole) to rainfall variability in Marihat and Bekri Plantation and the reation with palm oil production. The correlation between those ENSO and IOD events with rainfall variability and palm oil production was analyzed using Canonical Correlation Analysis. This method uses two variables, which are rainfall and palm oil production as a Dependent variables and SOI (Southern Oscillation Index), Sea Surface Temperature Anomaly of Nino 3-4 region (120°W-170°W and 5°S- 5°N) and DMI (Dipole Mode Index) as an Independent variables. The result of this study indicates that SOI, SSTA and DMI not closely related to rainfall in those two plantations area. Statistical analysis revealed that ENSO and IOD significantly related to rainfall in Marihat plantation on the same month until 4th month (lag 0-4) and on the 8th - 12th month (lag 8-12). Fluctuation of palm oil production due to the impact of ENSO and IOD will start on 4th-11th month after water stress occurrence. The most impacted area in Marihat Plantation is Helvetia. In Bekri plantation, the correlation between climate deviation and rainfall is stronger. According to statistical analysis, ENSO and IOD significantly related to rainfall in Bekri plantation on the same month (lag 0) and 7th – 9th month (lag 7-9). It means that the impact of ENSO and IOD to fluctuation palm fruit production will be on the next 7th – 9th month after water stress occurrence.
Keyword: 

Judul: Closed Knight’s Tour pada Papan Catur Berbentuk Persegi Panjang dengan Ukuran Maksimal 8 × 8
Abstrak: Closed Knight’s Tour merupakan langkah kuda yang mengunjungi setiap kotak pada papan catur tepat satu kali dengan langkah kuda berawal dan berakhir pada kotak yang sama. Graf yang terbentuk dari closed knight’s tour dinotasikan sebagai graf G(m,n), dengan m adalah banyaknya baris dan n adalah banyaknya kolom. Graf tersebut memuat Hamiltonian cycle. Sebuah graf terhubung G adalah graf bipartite jika dan hanya jika graf tersebut tidak memiliki cycle dengan panjang ganjil. Papan catur yang memenuhi syarat cukup untuk memiliki closed knight’s tour adalah papan catur berukuran 5 × 6, 5 × 8, 6 × 6, 6 × 7, 6 × 8, 7 × 8, dan 8 × 8.
Keyword: bipartite, closed knight’s tour, hamiltonian cycle, knight’s tour, teori graf