Judul: Hambur Balik Total Padatan Tersuspensi menggunakan metode akustik di Perairan Rokan Hilir Bengkalis, Riau
Abstrak: Total Padatan Tersuspensi (TSS) adalah bahan-bahan tersuspensi (berdiameter > 1 μm) yang tertahan pada saringan miliopore dengan diameter pori 0,45 μm. Tingginya Konsentrasi TSS akan menghambat penetrasi cahaya ke dalam air dan mengakibatkan terganggunya proses fotosintesis. Penelitian ini bertujuan untuk memperoleh nilai hambur balik (Sv) TSS dengan menggunakan metode akustik dan dibandingkan dengan data TSS dari hasil Analisis Gravimetri di perairan Rokan Hilir Bengkalis Riau. Data penelitian ini merupakan hasil kerjasama dengan pemerintah kabupaten Rokan Hilir Provinsi Riau dengan topik “Survei Potensi Sumberdaya Perikanan di Perairan Rokan Hilir Bengkalis, Riau”. Total Padatan Tersuspensi (TSS) pada Perairan Rokan Hilir Bengkalis berkisar antara 8 – 260 mg/l menggunakan metode Gravimetri. Pendeteksian Nilai hambur balik TSS tersebut menggunakan Biosonik memperoleh kisaran nilai Sv sebesar (-88,2 dB hingga -75 dB). Analisis Regresi antara nilai Sv dan TSS diperoleh R2 bernilai 0,12., Total Suspended Solid is restrained substance (diameter > 1 μm) that impeded in miliopore strainer with pore diameter 0,45 μm. High concentrate will impede light penetration into the water and hampered the photosynthesis proses. The aim of this research is to obtain backscattering strength of Total Suspended Solid using acoustics method and compare with TSS data from Gravimetry analysis result. This research data was cooperation result with Rokan hilir government in Riau Province with topic “ The potential of fisheries resources survey in Rokan hilir bengkalis waters, Riau”. Total Suspended Solid in Rokan Hilir Bengkalis waters range between 8 – 260 mg/l using Gravimetry method. Backscattering strength of TSS using Biosonic DT-X obtain Sv value between - 88,2 dB up to -75 dB. Regression analyse between Sv value and TSS retrieve R2 with value 0,12.
Keyword: TSS, Metode akustik, Hambur balik, TSS

Judul: Analisis Acoustic Backscattering Dasar Laut di Perairan Pulau Tidung, Kepulauan Seribu
Abstrak: Pulau Tidung memiliki potensi besar sebagai daerah tujuan wisata bahari. Perencanaan dan pengembangan pembangunan Pulau Tidung memerlukan pemahaman mengenai kondisi perairan termasuk dasar perairannya. Penelitian ini bertujuan mengukur dan menganalisis nilai volume backscattering strength (SV) dan nilai surface backscattering strength (SS) berbagai tipe substrat dasar perairan di Perairan Pulau Tidung dengan menggunakan instrumen hidroakustik Single Beam Echosounder SIMRAD EK15. Pengambilan data akustik dilakukan dengan pemeruman secara stasioner, data oseanografi dengan menghanyutkan CTD AML Minos-10 dan data sedimen diambil serta dianalisis di laboratorium yang dilakukan oleh Prof. Henry Manik, S.Pi., M.T., Ph D. beserta dengan timnya. Penelitian ini berfokus pada pengolahan data menggunakan software Sonar 5 Pro. Analisis data akan menghasilkan nilai SV yang akan digunakan untuk menghitung nilai SS. Kecepatan suara sebesar 1.541,58 m/s sampai 1.543,03 m/s. Nilai SV tertinggi dari pecahan kerang bercampur rubble yaitu sebesar -9,84 dB, sedangkan nilai terendah dari pasir sangat halus sebesar -19,07 dB sampai -18,08 dB. Nilai SS tertinggi dari pecahan kerang bercampur rubble sebesar -15,92 dB dan terendah dari pasir sangat halus sebesar -25,15 dB sampai -24,15 dB. Perbedaan antara nilai SS yang diperoleh dari jenis sedimen yang sama disebabkan oleh perbedaan ukuran, berat dan juga persentase komposisi fraksi. Hasil analisa yang diperoleh dari hubungan MGS dan SS berupa nilai koefisien korelasi sebesar 0,5555 dikategorikan cukup kuat dan nilai koefisien determinasi sebesar 0,3086 yang artinya 30,86% SS dipengaruhi oleh nilai MGS. Kata kunci: hidroakustik, Pulau Tidung, regresi linier, surface backscattering strength, volume backscattering strength., Tidung Island has great potential as a marine tourism destination. Planning and developing the development of Tidung Island requires an understanding of the condition of the waters including the bottom of the waters. This study aimed to measure and analyze the volume backscattering strength (SV) and surface backscattering strength (SS) values of various types of bottom water substrates using the hydroacoustic single beam echosounder Simrad EK15. Acoustic data was collected by stationary sounding, oceanographic data by washing away CTD AML Minos-10 and sediment data were collected and analyzed in a laboratory conducted by Prof. Henry Manik, S.Pi., M.T., Ph. D. and his team. This study focuses on data processing using Sonar 5 Pro software. Data analysis will produce an SV value which will be used to calculate the SS value. The highest SV value was obtained from crushed coral mixed with rubble, which was -9.84 dB, while the lowest value was from very fine sand which was -19.07 dB to -18.08 dB. The highest SS values were obtained from crushed coral mixed with rubble of -15.92 dB and the lowest for very fine sand was -25.15 dB to -24.15 dB. The difference between the SS values obtained from the same sediment type is caused by differences in size, weight and also the percentage of fraction composition. The results of the analysis obtained from the relationship between MGS and SS are in the form of a correlation coefficient value of 0.5555 which is categorized as quite strong and a coefficient of determination of 0.3086 which means that 30.86% of SS is influenced by the MGS value. Keywords: hydroacoustic, linear regression, surface backscattering
Keyword: hydroacoustic, volume backscattering strength, surface backscattering strength, Tidung Island, linear regression

Judul: The Exploration of Discrete Logarithm over Finite Field GF(3m)
Abstrak: The security of many public~key algorithms is based on the problem of finding discrete logarithms. The generalized discrete logarithm problem is the following: given a finite cyclic group G of order n, a generator a of G, and an element fl E G, find the integer x, 0 ~ x ~ n - 1, such that 0: = fl. Algorithm for discrete logarithm problem focused on Menezes et al. (1997) that consist of exhaustive search algorithm, the baby-step giant-step algorithm, Pollard's rho algorithm, Pohlig-Hellman algorithm, and index-calculus algorithm. These algorithms are explorated to be used in discrete logarithm problem over finite field GF(3m ). The exploration also produces some algorithms, i.e. naif negative algorithm, baby-step mother-step algorithm, baby-step mother free-step algorithm, and baby-step free-step algorithm. All algorithms implemented using Maple 11. The Pohlig-Hellman and baby-step giant-step algorithms are efficient enough to be used in discrete logarithm problem over finite field GF(3m ) for m < 20.
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