Implementasi One TIME Pad Kriptografi Pada Gambar Grayscale Dan Gambar Berwarna

Penyandian pesan melalui teknik kriptografi terus berkembang, salah satunya yaitu penggunaan algoritma One Time Pad (OTP) yang semula hanya digunakan untuk menyandikan tulisan kini dapat digunakan untuk menyandikan gambar. OTP merupakan algoritma kriptografi klasik kunci simetris yang sangat aman untuk menyandikan gambar, bahkan sampai saat ini beklum terpecahkan. Hal ini dikarenakan panjang kunci yang digunakan sama dengan panjang plainteks yang dalam pengoperasiannya harus dalam keadaan random dan tidak boleh digenerate. Hasil eksperimen diuji menggunaan Peak Signal to Noise Ratio (PSNR), Bit Error Ratio (BER), Cross Correlation (CC). Pada kriptografi, nilai PSNR semakin mendekati 0 artinya gambar tersandikan sempurna yang bertolak belakang dengan watermarking. Pada watermarking nilai PSNR lebih dari 40 dB membuktikan tingkat keberhasilan yang baik. Makalah ini menyajikan hasil eksperimen pada 24 gambar keabuan dan gambar berwarna untuk proses enkripsi dan dekripsi. Hasil PSNR proses enkripsi terbaik yaitu 7,4134 dB, BER 26230 sedangkan proses dekripsi berhasil dengan bukti nilai PSNR infinitive, BER dan MSE dari seluruh gambar bernilai 0. Untuk mengetahui perbedaan gambar asli dengan gambar hasil kriptografi, perbedaan nilai dari hasil percobaan disajikan dalam bentuk histogram. Kata Kunci: One Time Pad, Kriptografi, Citra, PSNR, BE

Uji Performa Watermarking 256x256 Citra Keabuan dengan Least Significant Bit

Pada era digitalisasi seperti sekarang, hampir semua data multimedia dapat ditemukan via internet. Kemudahan dalam mengakses internet berdampak pada semakin sulitnya membatasi tindakan copy paste terhadap foto karya orang lain sehingga dibutuhkan adanya teknik untuk mengamanakan data. Salah satu teknik yang dapat digunakan untuk mengamankan data yaitu watermarking, Dalam perkembangannya, watermarking digunakan untuk copyright protection dan digital signature baik dalam ranah visible maupun invisible. Dalam watermarking dikenal salah satu algoritma yang dikategorikan dalam spasial domain, yaitu Least Significant Bit (LSB). LSB mempunyai kelebihan mudah dan cepat untuk diterapkan. Dalam penelitian ini LSB dianalisa untuk mengamankan citra watermarking sehingga data aman dari orang yang tidak berkepentingan. Keberhasilan dari percobaan ini dapat dilihat dari nilai Peak Signal to Noise Ratio (PSNR). Pada makalah ini, percobaan telah dilakukan dengan menguji 5 citra keabuan berukuran 256x256 dengan citra pesan 128x64 piksel dan menghasilkan piksel tertinggi 54.6667 dB

Maturation and fertilisation of sheep oocytes cultured in serum-free medium containing silk protein sericin

Sericin is a water-soluble component of silk and has been used as a biomaterial due to its antibacterial and ultraviolet radiation-resistant properties. This study was designed to evaluate the effect of sericin supplementation in a maturation medium on the meiotic competence and fertilisability of sheep oocytes. Cumulus-oocyte complexes (COCs) were cultured in TCM199 supplemented with sericin at various concentrations of 0 (control), 0.1, 0.25 and 0.5%, either with or without bovine serum albumin (BSA). When the COCs were matured without BSA, the supplementation of 0.1% sericin significantly increased the rates of maturation to metaphase II and the total fertilisation of oocytes compared with the other concentrations of sericin. When the COCs were matured with BSA, the beneficial effects of 0.1% sericin supplementation on the maturation and fertilisation of oocytes were not observed. Our findings indicate that supplementation with 0.1% sericin during maturation culture may improve the nuclear maturation and fertilisability of sheep oocytes. Moreover, it may be possible to replace BSA with sericin in chemically defined media without the risk of disease transmission

Analysis of the Aspergillus fumigatus Proteome Reveals Metabolic Changes and the Activation of the Pseurotin A Biosynthesis Gene Cluster in Response to Hypoxia

The mold Aspergillus fumigatus is the most important airborne fungal pathogen. Adaptation to hypoxia represents an important virulence attribute for A. fumigatus. Therefore, we aimed at obtaining a comprehensive overview about this process on the proteome level. To ensure highly reproducible growth conditions, an oxygen-controlled, glucose-limited chemostat cultivation was established. Two-dimensional gel electrophoresis analysis of mycelial and mitochondrial proteins as well as two-dimensional Blue Native/SDS-gel separation of mitochondrial membrane proteins led to the identification of 117 proteins with an altered abundance under hypoxic in comparison to normoxic conditions. Hypoxia induced an increased activity of glycolysis, the TCA-cycle, respiration, and amino acid metabolism. Consistently, the cellular contents in heme, iron, copper, and zinc increased. Furthermore, hypoxia induced biosynthesis of the secondary metabolite pseurotin A as demonstrated at proteomic, transcriptional, and metabolite levels. The observed and so far not reported stimulation of the biosynthesis of a secondary metabolite by oxygen depletion may also affect the survival of A. fumigatus in hypoxic niches of the human host. Among the proteins so far not implicated in hypoxia adaptation, an NO-detoxifying flavohemoprotein was one of the most highly up-regulated proteins which indicates a link between hypoxia and the generation of nitrosative stress in A. fumigatus

A people-centred perspective on climate change, environmental stress, and livelihood resilience in Bangladesh

The Ganges–Brahmaputra delta enables Bangladesh to sustain a dense population, but it also exposes people to natural hazards. This article presents findings from the Gibika project, which researches livelihood resilience in seven study sites across Bangladesh. This study aims to understand how people in the study sites build resilience against environmental stresses, such as cyclones, floods, riverbank erosion, and drought, and in what ways their strategies sometimes fail. The article applies a new methodology for studying people’s decision making in risk-prone environments: the personal Livelihood History interviews (N = 28). The findings show how environmental stress, shocks, and disturbances affect people’s livelihood resilience and why adaptation measures can be unsuccessful. Floods, riverbank erosion, and droughts cause damage to agricultural lands, crops, houses, and properties. People manage to adapt by modifying their agricultural practices, switching to alternative livelihoods, or using migration as an adaptive strategy. In the coastal study sites, cyclones are a severe hazard. The study reveals that when a cyclone approaches, people sometimes choose not to evacuate: they put their lives at risk to protect their livelihoods and properties. Future policy and adaptation planning must use lessons learned from people currently facing environmental stress and shocks