Judul: Steganografi pada File DNA Berformat Fasta dengan Metode DNA Rekombinan
Abstrak: Steganography is a technique of inserting information into a media. This technique focuses on removing suspicion of storage media messages. Hiding information with this technique usually is performed in media images, sounds, and text documents. Those media are already common for use as storage media messages, which has low capacity and stood by people. This is a problem that will lead to greater suspicion on such media.The solution is then offered to find new media that has a high level of random, hard to understand and has a large capacity. This study discussed the application of steganography in the media Fasta-formatted file of DNA using recombinant DNA. Insertion was done by replacing certain parts of DNA sequences of DNA on file with the message. The message that would be inserted first converted into the form of DNA sequences.The performance of the insertion of messages with recombinant DNA method was tested by analyzing the properties of steganography that were imperceptible, fidelity, recovery and analysis of safety. Testing the quality of a DNA file was done by using BLAST as a tool to determine the similarity of DNA sequences located on the internet. The results showed that the insertion of recombinant DNA method provides a vague presence of a message, to make the process of extracting the message and producing good quality media. Thus steganography in Fasta-formatted file of DNA using recombinant DNA method is a good solution as the new media that has a high level of random.
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Judul: Teknik Steganografi pada Rich Text Format File dengan Memanfaatkan Atribut Warna Teks
Abstrak: Steganography technique is a technique hiding the existence of message using a specific media as a place of insertion of the message. Steganography technique aims to avoid the suspicious of existence of the inserted messages. One of the media used in the technique of steganography is digital text media. In this research, digital text used as insertion of media files such as rich text format. Rich text format files are selected for its ability to accommodate large numbers of messages. The idea that are used to insert the secret message in rich text format files is by using the rich text format compiler attribute. Compiler attributes that is used as a place to insert the message is the color attribute. Results from this study compared the rates of change that occurred in the document size before and after the inserted messages and calculate the maximum capacity of messages that can be pasted into a document in rich text format. A change in the size of the cover-text depends on the size of the inserted messages. The bigger the messages that are inserted, then the size of the cover-text has to get bigger. The maximum message size that can be inserted in a rich text file formats depends on the number of spaces available in rich text file format. In this research, the technique of steganography in rich text format file using a text color attribute is resistant to the process of storage or transmission uses the Internet and the read only by using some word processor applications. However, steganography technique in rich text format file using a text color attribute is not resistant to the process of conversion of files into the form of Portable Document Format (*.PDF) and return the storage process stego-text using word processor applications.
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Judul: Thermal Characteristics and Dynamics of Tropical Cyclone over Western North Pacific Ocean: A Case Study of Typhoon Songda (Chedeng) 2011
Abstrak: The frequent occasion of Tropical Cyclone (TC) over Western North Pacific (WNP) Ocean lies from 10˚N to 26˚N and 121˚E to 170˚E. Sources of TC development come from warm ocean temperature where latent heat is released during condensation processes and subsequently concentrated in the boundary layer. Relative humidity at 850-700 hPa is responsible to produce the most intense storm. Meanwhile, weak vertical wind shear between 850-200 hPa is one of the dynamical factors that lead to the development of TC. Pressure level of 850-200 hPa is chosen to minimize the thermodynamic effect in the lower troposphere. Typhoon Songda (Chedeng in the Philippines) or TSC lasted from May 18th to 30th, 2011 and strengthened into powerful Super Typhoon stage between May 24th and 27th. Long curving track and the exhibition of all sequences of TC life cycle, TSC is then considered as an ideal case of TC. The objective of the study with case of TSC is to investigate the role of thermal characteristics and dynamics on TC intensity. The research is carried out by using Advanced Research of Weather Research and Forecasting model (WRF ARW model) version 3.3. Two domains are employed in the model. The first domain situate from 02˚N to 40˚N and 118˚E to 149˚E and cover spatial resolution () of 33.1 km. The second domain situate from 09˚N to 27˚N and 119˚E to 132˚E with of 11 km. Timestep of the model () is 120 seconds. The model is supported by the following physical parameterization, i.e., Yonsei University Scheme (YSU) in the boundary layer, Kain-Fritsch scheme (KF) in the cumulus, and WRF Single-Moment 3-class scheme in the microphysics. Initial meteorological condition prior to the formation of the cyclone is generated using WRF ARW standard-release model. Sensitivity of the model output is obtained from a selected single-parameter change scenarios, namely, 10 % to 20 % decrease and increase of wind shear initial data at 850-200 hPa, and by 10 % to 20 % decrease of relative humidity initial data at 850-700 hPa. The result showed that the negative correlations between wind shear and intensity are found in wind shear scenarios. Wind shears of 10 ms-1 which lead to strengthening of the wind intensity in the early period of Typhoon development are found in wind shear scenarios. The effect of wind shear changes on wind intensity is statistically significant in the 20 % wind shear scenarios. During mature stage, weak wind intensity occurred when wind shear increase as given in the WRF standard-release and the 20 % decreasing scenario. Different situation is found in the 20 % increasing scenario where wind shear tend to weak and lead to strong wind intensity at this stage. Meanwhile, the reduction of moisture supply at 850-700 hPa resulting from 20 % decreasing relative humidity play a major role in the weakening of wind intensity and reduces mechanical energy of the cycle process as much as 300 J kg-1.
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