Judul: Stratification and Structure of Water Mass in the North Papua
Abstrak: Perairan Utara Papua barada di sisi Pasifik Ekuator dan dilintasi oleh sistem Arus Pantai Papua yang membawa massa air Pasifik Selatan dimana massa air ini sebagai bagian dari sumber Arus Lintas Indonesia yang melintasi Laut Halmahera. Penelitian ini bertujuan untuk mendeskripsikan stratifikasi dan jenis massa air di Utara Kepala Burung Papua dengan menggunakan data CTD dari hasil kegiatan survei Kajian Stok Sumber Daya Ikan Nasional Juli 2015 serta keluaran model arus dekat permukaan. Stratifikasi lapisan tercampur dan termoklin dihitung dari gradien vertical suhu terhadap kedalaman dengan gradien 0,05 °C/m. Jenis massa air dianalisis dari diagram TS, TO, dan SO. Hasil penelitian menunjukan lapisan tercampur berkisar 67-109 m, dimana suhu, salinitas, densitas, dan oksigen terlarut relatif homogen di lapisan ini. Ketebalan lapisan termoklin berkisar antara 113-244 m di kedalaman 68-312 m, stasiun sebelah timur cenderung lebih tebal dibandingkan sebelah barat sekitar 17 m. Pengukuran CTD dilakukan sampai kedalaman sekitar 500 m, sehingga jenis massa air yang ditemukan utamanya massa air Subtropis Pasifik Selatan (South Pacific Subtropical Water, SPSW) pada kedalaman 97-188 m dengan kisaran suhu, salinitas, dan oksigen terlarut masing-masing 19,06-26,18 °C, 35,01-35,48 PSU, dan 3,98-4,91 mg/l., The Northern sea of Papua are on the Pacific side of the Equator and are crossed by the Papua Coastal Current system which carries the South Pacific water mass where this water mass is part of the source of the Indonesian Through Flow that crosses the Halmahera Sea.This study aims to describe the stratification and type of water mass in the North of Papua using CTD data from the results of the July 2015 National Fish Resource Stock Study survey and the output of the near-surface current model. Mixed layer stratification and thermocline were calculated from the vertical gradient of temperature with depth with a gradient of 0.05 °C/m. The type of water mass was analyzed from the TS, TO, and SO diagrams. The results showed that the mixed layer ranged from 67-109 m, where the temperature, salinity, density, and dissolved oxygen were relatively homogeneous in this layer. The thickness of the thermocline layer ranges from 113-244 m at a depth of 68-312 m, the east station tends to be thicker than the west about 17 m. CTD measurements were carried out to a depth of about 500 m, so that the type of water mass found was mainly South Pacific Subtropical Water (SPSW) at a depth of 97-188 m with a temperature, salinity, and dissolved oxygen range of 19,06 -26,18 °C, 35,01-35,48 PSU, and 3,98-4,91 mg/l.
Keyword: CTD, Lapisan Termoklin, Massa Air, Stratifikasi, Utara Kepala Burung Papua

Judul: Seasonal Variation of Mixed Layer Depth and Thermoclin Thickness using CTD Argo Float Data in Makassar Strait
Abstrak: Selat Makassar berbatasan langsung dengan Laut Sulawesi di bagian utara dan Laut Jawa dan Laut Flores di bagian selatan, dan merupakan jalur utama Arus Lintas Indonesia (Arlindo). Sehingga stratifikasi massa air di Selat Makassar dipengaruhi oleh dinamika dari perairan laut tersebut. Penelitian ini bertujuan untuk mendeskripsikan variasi musiman dari stratifikasi massa air kedalaman lapisan tercampur dan kedalaman lapisan termoklin, dan mengidentifikasi kejadian upwelling pantai di bagian selatan Makassar. Data deret-waktu suhu salinitas kedalaman diperoleh dari pengukuran autonomus CTD Argo Float (ID 5904965) pada periode Desember 2017-November 2018. Hasil penelitian ditemukan massa air North Pacific Subtropical Water (NPSW) dan North Pacific Intermediate Water (NPIW) yang dominan di lokasi studi, dengan ciri salinitas maksimum 34,6-34,7 psu di lapisan termoklin dan salinitas minimum 34,5 psu di lapisan pertengahan. Ditemukannya massa air salinitas rendah dari Laut Jawa juga dominan dalam musim barat di lapisan dekat permukaan. Variasi musiman kedalaman lapisan tercampur di musim barat (DJF) tercatat lebih tebal sekitar 93 m, serta lapisan termoklin lebih tebal di musim timur sekitar 198 m. Perubahan ketebalan kedua lapisan tersebut diduga berkaitan dengan dinamika Arlindo Makassar dan Arus Monsun Jawa, misalnya Arlindo menguat pada musim timur sehingga lapisan termoklin menjadi tebal. Kejadian upwelling pantai pada musim timur (JJA) ditandai dengan penaikan isotherm 27°C, isohaline 34,0 psu dan isopiknal 22,0 kg/m3dari kedalaman sekitar 75 m ke permukaan laut., The Makassar Strait (MS) is directly connected to the Sulawesi Sea in the north and the Java Sea and the Flores Sea in the south, and is the main route of the Indonesian Througflow (ITF). Hence stratification of water mass in the MS is influenced by the dynamics of the sea waters. This study aims to describe seasonal variations of the mixed layer and the thermocline thickness, and to identify the ITF water masses as well as the occurrence of coastal upwelling in the southern part of the MS. Temperature-salinity-depth time series dataset were obtained from oneyear CTD Argo float measurements (ID 5904965) between December 2017- November 2018. The results show that North Pacific water origin of North Pacific Subtropical Water (NPSW) and North Pacific Intermediate Water (NPIW) are dominant, with a maximum salinity characteristic of 34.6-34.7 psu in the thermocline layer and a minimum salinity of 34.5 psu in the intermediate layer. Furthermore, near-surfave fresh Java Sea water appears to be dominant during the northwest monsoon (NWM) period. Seasonal variation of mixed layer depth much deeper (93 m) and much stronger vertical gradient of temperature and salinity due to the presence fresh Java Sea water advevted by the Java Monsoon Current during the NWM period (DJF). However, during the southeast monsoon (SEM) period the mixed layer depth is much shallower and thermocline layer is much thicker (198) m, associated with much stronger the ITF and upwelled colder water from upwelling area. The coastal upwelling event during the SEM period (JJA) in the study area is characterized by an increase of isotherm of 27°C, isohaline of 34.0 psu and isopycnal of 22.0 kg/m3 from 75 m depth to the sea surface layer.
Keyword: CTD Argo Float, ITF, Makassar Strait, Mixed Layer Depth, Thermocline Layer Thickness, Upwelling, Water Masses

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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