Judul: Pengukuran Sinyal Hambur Balik Pipa dan Dasar Laut Menggunakan Instrumen Side Scan Sonar
Abstrak: One of the instruments that is used in seafloor mapping is side scan sonar. In general, research about side scan sonar is mostly conduct to image processing itself. The aim of this research is to visualize image of seafloor with mosaic, data computation with wavelet from seafloor target and hopefully improve the intrepretation quantitavely. Side scan sonar data on November 2010 in Balongan, Indramayu from BPPT is used in this research. Visualization of side scan sonar data is done with mosaic. Morlet wavelet transformation is used for data analysis. Colour intensity in side scan sonar image can represent backscatter. Based on visualization and data analysis, higher of reflection coefficient, sound wave that is reflected back from target will be higher too. Magnitude form wavelet coefficients from target shows different result with colour gradation. Magnitude wavelet coefficient from the first target shows highest value in the data range 500 - 600, second target in range 200 - 300, and the third target with low backscatter in range 500 - 600
Keyword: Bogor Agricultural University (IPB), wavelet, target, side scan sonar, backscatter

Judul: Processing and Analysis of Seabed Acoustic Backscatter in Yos Sudarso Bay, Jayapura Using Side Scan Sonar Instrument
Abstrak: Side Scan Sonar merupakan instrumen yang digunakan untuk pencitraan dasar laut. Side Scan Sonar mampu membedakan permukaan dasar laut seperti batuan, lumpur, pasir, serta mendeteksi keberadaan pipa dan kabel laut. Penelitian ini bertujuan menginterpretasi dasar laut secara visual dan menganalisa nilai hamburbalik (dB) dengan metode Continuous Wavelet Transform (CWT) untuk mengetahui jenis substrat dasar laut. Data yang digunakan merupakan hasil pendeteksian instrumen Side Scan Sonar CMAX CM2 Towfish di perairan Teluk Yos Sudarso dengan 3 lintasan survei. Pengolahan data citra Side Scan Sonar meliputi koreksi geometrik dan koreksi radiometrik menggunakan perangkat lunak Sonarwiz 7. Koreksi geometrik meliputi bottom track dan slant range correction, serta koreksi radiometrik meliputi Beam Angle Correction (BAC), Automatic Gain Control (AGC), dan Time Varying Gain (TVG). Konversi data menggunakan perangkat lunak XtftoSegy, ekspor nilai amplitudo dengan Seisee, kemudian menampilkan hubungan amplitudo dan waktu, serta CWT menggunakan Matlab. Hasil penelitian ini diperoleh target berupa dua pasir dan satu karang. Hasil perhitungan nilai hamburbalik karang sebesar -5,0413 dB pada lintasan 6. Nilai hamburbalik pasir sebesar -15,4362 dB pada lintasan 7. Nilai hamburbalik pasir sebesar -14,2007 dB pada lintasan 8. Analisis Continuous Wavelet Transform menunjukkan target dengan tekstur keras dan kasar memiliki intensitas berwarna kuning pada scalogram, sedangkan target dengan tekstur lebih halus dan lunak memiliki intensitas berwarna biru pada scalogram., Side Scan Sonar is an instrument that is usually used to perform seabed imaging. Side Scan Sonar can distinguish seabed such as rocks, silt, sand, and detect the existence of marine pipes and cables. The aim of this research was to interpretate the seabed visually and analyze the backscatter (dB) with Continuous Wavelet Transform (CWT) for determine the type of seabed substrate. The data used from the detection of Side Scan Sonar C-Max CM2 Towfish instrument in Yos Sudarso Bay with 3 survey lines. Processing data Side Scan Sonar Image consisting of geometric corrections and radiometric corrections using Sonarwiz 7 software. Geometric corrections consist of bottom track and slant range, and radiometric corrections consist of Beam Angle Correction (BAC), Automatic Gain Control (AGC), and Time Varying Gain (TVG). Data was converted by XtftoSegy, amplitudo values were exported by Seisee, and displaying relation of amplitude and time, and CWT using Matlab. The results of this research were two sands and one coral target. The backscatter value of coral was -5,0413 dB on line 6. The backscatter value of sand was -15,4362 dB on line 7. The backscatter value of sand was -14,2007 dB on line 8. Continuous Wavelet Transform analysis shows that targets with hard and coarse textures have a yellow intensity on the scalogram, while targets with smooth and soft textures have a blue intensity on the scalogram.
Keyword: backscatter, continuous wavelet transform, side scan sonar, yos sudarso bay

Judul: Penapisan Inhibitor Tirosinase pada Empat Spesies Famili Asteraceae Chrysantemum morifolium R, Gerbera jamesonii A, Dahlia rosea Cav, dan Tagetes erecta.
Abstrak: The research was conducted to screen the potency of tyrosinase inhibitor from 4 species of Asteraceae family. The screening was performed on the leaves and flowers of Chrysantemum morifolium R, Gerbera jamesonii A, Dahlia rosea Cav, and Tagetes erecta. The samples were dried and then extracted with nhexane, ethyl acetate, and methanol. The inhibition activity was tested by a microplate reader spectrophotometer in 492 nm. The ethyl acetate extract of D. rosea Cav flower was the most potent tyrosinase inhibitor (IC50 for monophenolase 18.42 μg/mL and for diphenolase 687.79 μg/mL) compared with the other Asteraceae species. The most active essential oils as inhibitor of tyrosinase was obtained from T. erecta flower (IC50 for monophenolase 1882.62 μg/mL and for diphenolase 1884.33 μg/mL). Positive control used was kojic acid with IC50 value of 11.02 μg/mL for monophenolase and 84.19 μg/mL for diphenolase. Fractionation of the extract by preparative thin layer chromatography with chloroform as mobile phase gave 12 fractions. The most active fraction had IC50 of 5.55 μg/mL for monophenolase and 109.96 μg/mL for diphenolase, and was identified as flavonoid.
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