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

Testing the theory of immune selection in cancers that break the rules of transplantation

Modification of cancer cells likely to reduce their immunogenicity, including loss or down-regulation of MHC molecules, is now well documented and has become the main support for the concept of immune surveillance. The evidence that these modifications, in fact, result from selection by the immune system is less clear, since the possibility that they may result from reorganized metabolism associated with proliferation or from cell de-differentiation remains. Here, we (a) survey old and new transplantation experiments that test the possibility of selection and (b) survey how transmissible tumours of dogs and Tasmanian devils provide naturally evolved tests of immune surveillance

Mapping ergonomics application to improve SMEs working condition in industrially developing countries: a critical review

In industrially developing countries (IDC), small and medium enterprises (SMEs) account for the highest proprotion of employment. Unfortunately, the working conditions in SMEs are often very poor and expose employees to a potentially wide range of health and safety risks. This paper presents a comprehensive review of 161 articles related to ergonomics application in SMEs, using Indonesia as a case study. The aim of this paper is to investigate the extent of ergonomics application and identify areas that can be improved to promote effective ergonomics for SMEs in IDC. The most urgent issue found is the need for adopting participatory approach in contrast to the commonly implemented top-down approach. Some good practices in ergonomics application were also revealed from the review, e.g. a multidisciplinary approach, unsophisticated and low-cost solutions, and recognising the importance of productivity. The review also found that more work is still required to achieve appropriate cross-cultural adaptation of ergonomics application. Practitioner Summary: Despite continuous efforts in addressing ergonomics issues in SMEs of IDC, workers are still exposed to poor work conditions. We reviewed factual-based evidence of current ergonomics application to inform future strategies of ergonomics in IDC, using Indonesia as a case study

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

The bZIP Transcription Factor Rca1p Is a Central Regulator of a Novel CO2 Sensing Pathway in Yeast

Like many organisms the fungal pathogen Candida albicans senses changes in the environmental CO2 concentration. This response involves two major proteins: adenylyl cyclase and carbonic anhydrase (CA). Here, we demonstrate that CA expression is tightly controlled by the availability of CO2 and identify the bZIP transcription factor Rca1p as the first CO2 regulator of CA expression in yeast. We show that Rca1p upregulates CA expression during contact with mammalian phagocytes and demonstrate that serine 124 is critical for Rca1p signaling, which occurs independently of adenylyl cyclase. ChIP-chip analysis and the identification of Rca1p orthologs in the model yeast Saccharomyces cerevisiae (Cst6p) point to the broad significance of this novel pathway in fungi. By using advanced microscopy we visualize for the first time the impact of CO2 build-up on gene expression in entire fungal populations with an exceptional level of detail. Our results present the bZIP protein Rca1p as the first fungal regulator of carbonic anhydrase, and reveal the existence of an adenylyl cyclase independent CO2 sensing pathway in yeast. Rca1p appears to regulate cellular metabolism in response to CO2 availability in environments as diverse as the phagosome, yeast communities or liquid culture

Species Interactions during Diversification and Community Assembly in an Island Radiation of Shrews

Closely related, ecologically similar species often have adjacent distributions, suggesting competitive exclusion may contribute to the structure of some natural communities. In systems such as island archipelagos, where speciation is often tightly associated with dispersal over oceanic barriers, competitive exclusion may prevent population establishment following inter-island dispersal and subsequent cladogenesis.) species in the Philippines are the result of competitive exclusion preventing secondary invasion of occupied islands. We first compare ecological niche models between two widespread, allopatric species and find statistical support for their ecological similarity, implying that competition for habitat between these species is possible. We then examine dispersion patterns among sympatric species and find some signal for overdispersion of body size, but not for phylogenetic branch length. Finally, we simulate the process of inter-island colonization under a stochastic model of dispersal lacking ecological forces. Results are dependent on the geographic scope and colonization probability employed. However, some combinations suggest that the number of inter-island dispersal events necessary to populate the archipelago may be much higher than the minimum number of colonization events necessary to explain current estimates of species richness and phylogenetic relationships. If our model is appropriate, these results imply that alternative factors, such as competitive exclusion, may have influenced the process of inter-island colonization and subsequent cladogenesis.We interpret the combined results as providing tenuous evidence that similarity in body size may prevent co-occurrence in Philippine shrews and that competitive exclusion among ecologically similar species, rather than an inability to disperse among islands, may have limited diversification in this group, and, possibly other clades endemic to island archipelagos