Judul: Perbaikan dan Evaluasi Kinerja Algoritma  Pixel- Value Differencing (PVD)
Abstrak: Perkembangan teknologi informasi sekarang ini membuat komunikasi menjadi semakin mudah dan luas. Penyampaian pesan melalui internet merupakan sarana komunikasi yang sangat mudah dan efisien. Sejalan dengan hal itu kemunculan dari file-file multimedia yang beraneka ragam memberi pengaruh yang cukup besar dalam kemajuan teknologi informasi ini sehingga memungkinkan seseorang untuk dapat menyampaikan pesan menggunakan filefile multimedia tersebut. Faktor keamanan menjadi penting dalam proses pengiriman data melalui saluran internet. Apabila hal ini diabaikan , maka orang yang tidak berhak akan dengan mudah memanfaatkan data tersebut untuk tujuan tertentu. Jika hal ini terjadi ada dua pihak yang dirugikan yaitu pengirim data dan penerima data. Bertolak dari hal tersebut maka penelitian ini dilakukan dengan menggunakan metode steganografi, yang mengkaji dari kapasitas pesan dan distorsi yang terjadi. Penelitian ini bertujuan untuk melakukan perbaikan algoritma steganografi pixel value differencing (PVD) untuk meningkatkan kapasitas pesan dan meminimumkan distorsi.
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Judul: Pemanfaatan filterisasi untuk meningkatkan daya tampung pesan pada steganografi Pixel Value Differences (PVD)
Abstrak: On technique Pixel Value Differences (PVD) steganography before the secret message is inserted, the cover image of the first divided into blocks that do not overlap each other (non-overlapping pixel blocks). The excess value of the pixel is used to determine the amount of message bits that can be inserted. If the difference is large, then the message can be inserted in large numbers and vice versa. Image processing operations may affect the difference in value of adjacent pixels in an image. Therefore, by applying the filter in the PVD steganography is expected to increase the capacity of the message which is owned by a cover. Filtering done to the cover before the message is inserted. Type of filtration used is blur, emboss, and sharp. Research shows sharp have greatest increase their capacity without degrading performance value of Peak Signal to Noise Ratio (PSNR). Steganography application which developed is used in the process of inserting message, extracting messages, measuring the capacity of the message and PSNR value.
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Judul: Insecticidal Activity of Essential Oils Leaves of Cinnamomum spp. (Lauraceae) against Crocidolomia pavonana and Their Phytotoxicity on Broccoli Seedlings
Abstrak: Essential oils from leaves of 13 species of Cinnamomum were tested for their insecticidal activity on the cabbage head caterpillar Crocidolomia pavonana with leaf immerse method. The results showed that the treatment with 1% (w/v) essential oils leaves of C. celebicum, C. multiflorum, C. sintoc, and C. verum caused 21.45, 93.65, 60.30, and 76.10% mortality, respectively. Based on the results of phytotoxicity and insecticidal activity tests, C. multiflorum oil was further tested at 6 concentration levels. In all treatments, larval mortality has occurred at 24 hours after treatment (HAT) and increased at 48 HAT. LC50 of C. multiflorum oil at 24 and 48 HAT was 0.504 and 0.396%, respectively. The treatment with C. multiflorum oil at ≤0.31% did not inhibit the development of C. pavonana larvae. Determination of the chemical constituents of Cinnamomum oils were carried out by gas chromatography-mass spectrometry (GCMS). Totally, 345 compounds were identified. Methyleugenol constituted the main component (49.4%) of leaf essential oil of C. multiflorum and was assumed to be responsible for the insecticidal activity of the oil against C. pavonana larvae. LC50 of pure methyleugenol obtained at 0.365% (48 HAT) and 0.363% (72 HAT). The results showed that C. multiflorum was more effective with LC50 value equivalent to methyleugenol content of 0.32% (24 HAT) and 0.24% (48 HAT).
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