Judul: Deteksi dan Pemetaan Habitat Bentik Menggunakan Scientific Sonar Instrument.
Abstrak: Penelitian ini bertujuan untuk menghasilkan peta habitat bentik dari data akustik Side-scan sonar Starfish 990F frekuensi 1 MHz yang ditunjang dengan data batimetri, sampel dasar laut hasil grab sampling, dan underwater photography yang dilakukan di sebagian perairan Selat Lembeh, Bitung, Sulawesi Utara pada bulan April 2016. Data askutik Side-scan Sonar digunakan untuk klasifikasi tutupan dasar perairan menggunakan metode multiresolution segmentation dan decision tree dan ekstraksi nilai backscatter berdasarkan nilai piksel, nilai piksel merepresentasikan besarnya nilai pantulan dan hamburan energi target. Data batimetri digunakan untuk analisis slope dan relief dasar perairan. Sampel dasar laut hasil grab sampling dianalisis berdasarkan skala granulometri Wentworth untuk menghasilkan peta sebaran sedimen dasar laut. Klasifikasi tutupan dasar perairan membagi dasar perairan menjadi batuan, kerikil, pecahan karang, pasir, dan lumpur dengan nilai akurasi 0.821-0.9047. Setiap kelas tutupan dasar perairan dilakukan sampling nilai piksel untuk ditransformasi menjadi nilai backscatter dengan rentang nilai (-20) – (-70) dB, transformasi nilai backscatter menggunakan persamaan regresi antara nilai piksel dengan nilai backscatter, diperoleh persamaan y=-0.2328x-12.607 dengan koefisien determinasi 0.9837. Kombinasi klasifikasi dasar laut, batimetri, dan peta sebaran sedimen dasar laut menghasilkan peta habitat bentik yang mencakup informasi relief dan material dasar laut sebanyak 43 kelas kawasan habitat bentik. Sebagian besar habitat bentik Selat Lembeh merupakan habitat pasir, kerikil dan kombinasi keduanya. Relief yang sulit dan kasar seperti pada bagian lereng (slope) didominasi oleh batuan dan kerikil, sedangkan untuk relief datar cenderung didominasi oleh pasir.
Keyword: backscatter, habitat bentik, multiresolution segmentation, Side-scan Sonar

Judul: Deteksi dan Klasifikasi Dasar Laut Menggunakan Instrumen Side scan sonar
Abstrak: Side scan sonar is an underwater acoustic instrument that is capable for displaying the image of the seafloor and discriminate between large and small particles of the sea floor. This study aims to classify types of seafloor and measure seafloor backscatter values using side scan sonar. This study also use two different types of side scan sonar in two places to get more variant seafloor. Side scan sonar data of Klein System 3000 with a frequency of 500 kHz is taken in the Jakarta Bay and Data of Edgetech 4200 with a frequency of 300 kHz is taken in the Sunda Strait. Both the data side scan sonar processed using software Sonarweb and Sonarpro to display the image of the sea floor, and use Seisee to extract sediment backscatter values. Results of sea floor imagery in Jakarta Bay found the target in the form of mud, mud with excavation, and a shipwreck. Mosaic Klein System 3000 in Jakarta Bay seafloor show a dominant of mud. Extraction of backscatter obtained smallest value is mud -26.33 dB, mud with excavation -23.84 dB and the highest is shipwrecks -6.23 dB. Results seabed imagery found the target in the Sunda Strait seabed is mud, sand, biogenic sand, and a shipwreck. Seafloor in the Sunda Strait shows dominant of sand. Backscatter obtained smallest value is mud -14.25 dB , sand -12.22 dB, biogenic sand -13.56 dB , and shipwreck -4.20 dB.
Keyword: backscatter, Klein System 3000, Edgetech 4200, sediment

Judul: Approximation of the Median of Poisson Distribution Using the Relation of Poisson-Gamma Distribution
Abstrak: A major drawback of median is that median cannot usually be defined in closed form, even in the cases where their distribution functions are known. This study gives an approximation of the closed form for the median of the Poisson distribution by using the relation of Poisson-Gamma distribution. The approximation uses elementary techniques based on the monotonicity of certain sequences involving tail probabilities of the Poisson distribution and the Central Limit Theorem. Furthermore, a closed form expression for the mean absolute deviation 􀜧|􀜰􀰒 􀵆 􀜯􀝁􀝀􁈺􀜰􀰒􁈻| is also studied. The median is relevant because of the fact that it minimizes the mean absolute deviation of a Poisson random variable (􀜰􀰒􁈻 by considering median as central tendency.
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