Judul: Coastal Circulation and Trajectory Analysis of Water Particles Related to Oil Spill in the North Coastal Waters of Karawang
Abstrak: Perairan Pantai Utara Karawang adalah bagian dari Laut Jawa yang dipengaruhi oleh variabilitas muson. Sehingga interaksi antara muson dengan sirkulasi permukaan laut perairan Karawang diduga dapat mempengaruhi pola distribusi pencemar, terutama berkaitan dengan kejadian tumpahan minyak di perairan Karawang. Tujuan penelitian ini membangun model sirkulasi menggunakan CROCO, serta menganalisis pola sirkulasi dan trajektori partikel massa air sebagai tahap awal analisis tumpahan minyak. Penentuan titik keluaran tumpahan minyak menggunakan citra Sentinel-1A. Metode analisis data dengan Diagram Taylor, deret-waktu, klimatologi, sirkulasi permukaan laut, serta analisis trajektori menggunakan Ichthyop. Model yang dibangun dengan resolusi 1/96º (±1.159 km), dengan validasi SST, SSH, dan komponen arus (zonal dan meridional) menunjukkan korelasi yang tinggi (0.86, 0.87, 0.96, 0.91). Hasil penelitian menunjukkan tren kenaikan suhu terjadi di musim peralihan 1 dan 2 dan terendah di muson timur. Tren salinitas meningkat dari Februari-Oktober dan menurun dari November-Februari. Selama muson barat, pola sirkulasi air laut bergerak dari barat menuju timur dan mulai berbalik arah pada bulan April. Memasuki muson timur pola sirkulasi bergerak dari timur menuju barat. Dominansi arah arus ini juga ditemukan di musim peralihan 2. Hasil model CROCO digunakan untuk analisis trajektori partikel massa air dengan Ichthyop menunjukkan pergerakan partikel yang sesuai dengan arus yang terjadi pada bulan Juli, dimana secara keseluruhan pergerakan partikel didominasi pergerakan dari arah timur menuju barat dan mengikuti kontur topografi Pantai Utara Jawa., The waters of the North Coast of Karawang are part of the Java Sea which is influenced by monsoon variability. Thus, the interaction between monsoons and sea surface circulation in Karawang waters is expected to affect the distribution pattern of polluted materials, especially related to the oil spill event in Karawang waters. The objective of this study is to build circulation model using CROCO and analyze the circulation pattern and water mass trajectory as the preliminary stage of oil spill analysis. The released point of the oil spill is determined using Sentinel-1A imagery. Data analysis method using Taylor Diagrams, time series, climatology, sea surface circulation, and trajectory analysis using Ichthyop. This model used 1/96º resolution (±1.159 km), where SST, SSH, and current components validation showed high correlation (0.86, 0.87, 0.96, 0.91). The results showed that the trend of temperature is increased during monsoon breaks 1 and 2 while the lowest occurred in the southeast monsoon. The trend of salinity increased from February-October and decreased from November-February. During the northwest monsoon, the seawater circulation pattern moves from west to east and begins to reverse in April. Entering the southeast monsoon, the circulation pattern moves from east to west. The results of the CROCO model used for the analysis of water mass particle trajectories with Ichthyop showed that the particle movement corresponds to the current that occurred in July, where overall particle movement is dominated by current movement from east to west and through contours of the north coast of Java.
Keyword: the Java Sea, Ocean circulation, CROCO, Ichthyop, Trajectory, Oil spill

Judul: Oceanographic Dynamics  and Simulation of Sea Surface Circulation in the Makassar Strait
Abstrak: Selat Makassar merupakan bagian penting dari perairan global yang menghubungkan Samudera Pasifik dan Samudera Hindia dalam sirkulasi termohalin global dan juga dipengaruhi oleh banyak variabilitas yang ada di Perairan Indonesia. Tujuan dari penelitian ini adalah untuk mendeskripsikan kondisi oseanografi serta pola sirkulasi di Selat Makassar dan analisis trajektori massa air dari pantai Balikpapan. Dalam penelitian digunakan dari model CROCO resolusi 1/36º dengan rentang data 2015-2018 dan model Ichtyop dalam analisis trajektori. Data model digunakan untuk melihat variabilitas suhu, salinitas, arus, dan volume transpor. Hasil dari penelitian menunjukkan dinamika parameter oseanografi berfluktuasi secara musiman hingga kedalaman 60-70 m. Pada musim barat kondisi arus permukaan menuju ke utara. Pada musim timur arus berbalik menuju selatan. Volume transpor dominan terjadi di kedalaman termoklin yang mencapai maksimal ketika musim timur. Analisis trajektori pada permukaan terlihat partikel menyebar mengikuti pola arus musiman yang menuju Laut Sulawesi saat musim barat dan menuju Laut Jawa saat musim timur., Makassar Strait has main role in global circulation connecting Pacific Ocean and Indian Ocean as global thermohaline circulation system. Moreover Makassar Strait also influenced by many variability of Indonesian Seas. The aim of the study is to describe the oceanographic condition and circulation system of Makassar Strait, and analyze the water mass trajectory from Balikpapan coast. This study used CROCO models dataset with 1/36º resolution from 2015-2018 timeseries and Ichtyop model for trajectory analysis. The model dataset is used to observe the dynamic of oceanographic parameters such as temperature, salinity, ocean current, and transport volume. Result of the study revealed the dynamics of oceanographic parameters is fluctuate seasonally up to 60-70 m depth. During Northwest Monsoon (NWM) surface ocean current flows northward. During the Southeast Monsoon (SEM) the surface current flows opposite to the southward, The transport volume is dominated in termocline depth which maximum during SEM. The trajectory analysis at ocean surface revealed the particles spread following the seasonal change. During NWM is dominant flows to the Sulawesi Sea and during SEM flows to the Java Sea.
Keyword: Analisis Trajektori, Model CROCO, Selat Makassar

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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