Judul: Kajian Tumpahan Minyak Montara di Laut Timor Berdasarkan Metode Pengenalan Pola Spektral Citra Satelit ALOS-PALSAR
Abstrak: Pencemaran perairan yang diakibatkan tumpahan minyak dapat merusak lingkungan laut dan sumber daya hayati. Dampak pencemaran dapat mengganggu kegiatan ekonomi masyarakat pesisir. Penelitian ini bertujuan untuk menduga tumpahan minyak yang terdapat di perairan lokasi penelitian berdasarkan citra ALOS-PALSAR, mengidentifikasi tumpahan minyak, dan mengklasifikasikan tumpahan minyak Montara di Laut Timor berdasarkan nilai hambur balik dan indeks sebaran tumpahan minyak. Citra di-filter dengan berbagai ukuran kernel filter sehingga diperoleh nilai hambur balik citra yang tidak mengandung noise. Tumpahan minyak diklasifikasikan menjadi tiga kelas berdasarkan nilai hambur balik masing-masing piksel pada citra. Selang nilai hambur balik untuk masingmasing kelas tumpahan minyak, yaitu: tumpahan minyak berat adalah -34.00 s/d -31.52 dB, tumpahan minyak sedang adalah -31.52 s/d -30.18 dB, dan tumpahan minyak ringan adalah -30.18 s/d -27.49 dB. Berdasarkan nilai index sebaran tumpahan minyak (OSI), tumpahan minyak diklasifikasikan menjadi tiga kelas. Nilai index sebaran tumpahan minyak untuk masing-masing kelas tumpahan minyak, yaitu: tumpahan minyak berat adalah 0.17-0.34, tumpahan minyak sedang adalah 0.67-0.96, dan tumpahan minyak ringan adalah 1.03-1.25., Water pollution caused by oil spills could harm marine environment and biological resources. The impact of pollution can disrupt economic activities of coastal communities. This study aimed at suspected the oil spill in the waters research site based on the image data of the ALOS-PALSAR, identify and classify the Montara oil spill in the Timor Sea based on backscatter value and oil spread index. Image filtered with different filter kernel size in order to obtain the value of backscatter images that does not contain noise. Oil spills are classified into three classes based on backscatter of each pixel in the image. The range of Backscatter values for each class of oil spills, i.e.: heavy oil spill is -34.00 to -31.52 dB, medium oil spill is -31.52 to -30.18 dB, and light oil spill is -30.18 to -27.49 dB. Based on oil spread index (OSI), oil spills are classified into three classes. Oil spread index value for each class of oil spills, i.e: heavy oil spill is 0.17-0.34, medium oil spill is 0.67-0.96, and light oil spill is 1.03-1.25.
Keyword: Tumpahan minyak, filter, kernel, hambur balik, klasifikasi

Judul: Deteksi Tumpahan Minyak Montara di Laut Timor Menggunakan Citra MODIS dengan Berbagai Algoritma
Abstrak: Oil Spill in the Timor Sea that occurring in 2009 has caused oil expansion to an area of 10.842.81 km2. The Oil spill was successfully detected by MODIS imagery. The purpose of this study was to compare the detection of oil results from various algorithms with MODIS imagery and it’s visual appearances. The algorithm used is Oil Spill Index, Flourecence Index, Sea Surface Temperature (SST) Callison, Principal Component Analysis (PCA), and Normalized Difference Vegetation Index (NDVI). The appearance of oil spill in MODIS image extracted using oil spill index and flourecence index was brighter than the surrounding water bodies and has higher pixel values, while the appearance of oil spill on PCA and NDVI algorithms appeared darker than the surrounding water bodies and has a lower pixel value. The test accuracy of the algorithms are, 41%, 46%, 41%, and 60%, respectively.
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Judul: A Continuous Vaccination Strategy in the SVIR Epidemic Model
Abstrak: Vaccination is conducted to minimize the spread of a disease. The vaccination is usually done several times within a fixed time interval. In the SVIR model, it is assumed that individuals do not get immediate immunity following a vaccination program. So according to process of vaccination on SVIR model, there are two strategies, i.e. the continuous vaccination strategy (CVS) and the pulse vaccination strategy (PVS). In this study, only the CVS strategy in epidemic model SVIR is considered. Results of the study indicate that dynamics of the CVS system depends on the basic reproductive number. If the basic reproductive number is less than one, then the disease-free fixed point is asymptotically stable. It means that the disease will eventually disappear from the population. Conversely, if the basic reproductive number is greater than one, then the endemic fixed point is asymptotically stable, which means that the disease will remain exist in the population. Simulation result shows that the vaccination would minimize the spread of disease by reducing the basic reproductive number. If the time for the vaccinated recipients to obtain the immunity, as well as a possibility of vaccinated recipients to be infected are neglected, then the disease will be eradicated. This condition is called an over-evaluating effect of vaccination.
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