Judul: Implementasi dan Analisis Steganografi Audio Menggunakan Discrete Cosine Transform (DCT)
Abstrak: The rapid development of the internet and the digital information revolution caused significant changes in the global society, ranging from the influence on the world economy to the way people communicate. Digital communication strongly supports the ease of message exchange transactions, but on the other hand has a risk of security, especially for confidential messages. This research proposed implementation of steganography audio in WAV files transformed using DCT. The results of DCT coefficients are divided into an arbitrary number of segments and the energy of each segment is calculated. Text message are then embedded into the selected peaks of the highest energy segment with values ranging peaks from -0.4 – 0.4. Recovery text message from Stego-audio are extracted by performing the inverse operation of steganography embedding process. Simulation results indicate that a selected steganography technique meet the primary criteria of imperceptibility and recovery. In addition, the result of Signal-to-Noise Ratio (SNR) values range from 12dB – 40dB. The test quality of stego-audio makes use of objective and subjective analysis. The objective analysis uses Euclidean distance and the subjective analysis is based on survey
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Judul: Steganografi Video Dengan Menggunakan Metode Discrete Cosine Transform (DCT)
Abstrak: Information security nowadays has become a very important thing to note. A lot of confidential information such as personal data, financial data, and even state secrets confidential data needs to be protected so it cannot be misused by other people who are not authorized to do so. There are various methods to protect certain information, such as with cryptography and steganography. Cryptography change the original message into a meaningless message. This is important because with meaningless message, an unauthorized person can not know the contents of the message. But with the message is not meaningful, people would suspect that there is a hidden secret information inside the message and will try to break it. Therefore, this suspicion must be avoided and a suitable method to avoid suspicion is steganography which disguise a message so that its presence is not recognized by the other people. This research is about steganography applied in video using DCT method. Basically this method is modifying the DC coefficient bits in each byte of cover file. Text messages was inserted into video of .avi type format and then the message was retrieved from the video file. From the test results, it can be proved that the DCT method can be implemented in a video steganography. This method can qualify most criteria of steganography such as imperceptible, fidelity and recovery but not yet qualify the criteria of robustness. Nevertheless, there is still plenty of space that can be used in conducting the development of video steganography using DCT.
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Judul: Revisi marga Ptychopyxis miquel (Euphorbiaceae) di kawasan Malesia
Abstrak: Ptychopyxis adalah salah satu marga dari 317 marga yang termasuk ke dalam suku Euphorbiaceae. pertama kali dipublikasikan oleh Miquel (1860). Marga ini Marga ini pernah dimasukkan kedalam marga lain, yaitu Podadenia, Mallotus dan Clarorivinia. Fakta tersebut menunjukkan bahwa batasan marga Ptychopyxis belum cukup mantap. Persebaran marga ini menurut Van Welzen (1993) jumpai di Thailand, Indochina dan kawasan Malesia, di seluruhnya ada 23 jenis dan 10 jenis diantaranya terdapat di kawasan Malesia. Marga ini umum berperawakan pohon dan berumah dua, tumbuh di hutan hujan dataran rendah sampai pada ketinggian 1500 m dpl. Penelitian taksonomi yang komprehensif tentang marga ini telah dilakukan oleh Airy Shaw pada tahun 1960; sejak saat itu belum ada penelitian taksonomi yang lebih kompre- hensif, khususnya untuk kawasan Malesia. Kini dengan bertambahnya jumlah spesimen koleksi baru, maka tepatlah kiranya dilakukan revisi marga. Tujuan penelitian ini adalah untuk memberikan batasan marga serta jenis-jenisnya yang termasuk dalam Ptychopyxis selain itu diteliti pula hubungan kekerabatan antar jenis dan keterangan-keterangan..dst
Keyword: Herbarium Bogoriense, Podadenia, Mallotus, Clarorivinia