Judul: Sistem Keamanan Koleksi pada Perpustakaan Digital Menggunakan AES-128
Abstrak: Perpustakaan digital merupakan perpustakaan yang menyimpan koleksinya dalam bentuk file digital dan menyebarkannya melalui jaringan komputer. File digital mudah untuk diduplikasikan, hal ini menyebabkan kemungkinan terjadinya pelanggaran terhadap koleksi digital perpustakaan. Oleh karena itu diperlukan suatu metode keamanan untuk menjaga koleksi digital tersebut. Penelitian ini mencoba menerapkan metode keamanan koleksi digital dengan menggunakan enkripsi Advance Encryption Standard (AES) dengan panjang kunci 128 bit dengan menggunakan metode Cipher Block Chaining (CBC). Data yang digunakan pada penelitian ini berjumlah 50 file pdf yang merupakan koleksi penulis yang dikumpulkan dari berbagai sumber di Internet. Berdasarkan hasil pengujian enkripsi dan dekripsi didapat persentase keberhasilan mencapai 100%.
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Judul: Sistem peminjaman koleksi digital perpustakaan
Abstrak: Perpustakaan merupakan salah satu sarana untuk mendapatkan informasi yang dapat diakses oleh masyarakat umum. Salah satu bentuk koleksi yang mulai banyak dimiliki perpustakaan adalah file digital (koleksi digital). File digital memiliki sifat dan karakteristik yang berbeda, sehingga dibutuhkan mekanisme peminjaman yang berbeda. Penelitian ini dilakukan untuk membuat sistem yang dapat melindungi file digital koleksi perpustakaan dengan menggunakan kriptografi dan menambahkan informasi ke dalam file tersebut. Sistem yang dikembangkan adalah DigiLib Server dan DigiLib Client. DigiLib Server merupakan perangkat lunak yang dapat melakukan proses enkripsi terhadap file koleksi perpustakaan sekaligus menambahkan informasi ke dalam file koleksi tersebut. DigiLib Client merupakan perangkat lunak yang dapat melakukan proses dekripsi terhadap file koleksi yang telah terenkripsi oleh perangkat lunak DigiLib Server dan membaca informasi tentang aturan penggunaan file.
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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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