Automating risk analysis of software design models.

The growth of the internet and networked systems has exposed software to an increased amount of security threats. One of the responses from software developers to these threats is the introduction of security activities in the software development lifecycle. This paper describes an approach to reduce the need for costly human expertise to perform risk analysis in software, which is common in secure development methodologies, by automating threat modeling. Reducing the dependency on security experts aims at reducing the cost of secure development by allowing non-security-aware developers to apply secure development with little to no additional cost, making secure development more accessible. To automate threat modeling two data structures are introduced, identification trees and mitigation trees, to identify threats in software designs and advise mitigation techniques, while taking into account specification requirements and cost concerns. These are the components of our model for automated threat modeling, AutSEC. We validated AutSEC by implementing it in a tool based on data flow diagrams, from the Microsoft security development methodology, and applying it to VOMS, a grid middleware component, to evaluate our model's performance.

Comparative proteome and transcriptome analyses of embryonic stem cells during embryoid body-based differentiation.

Gene expression analyses of embryonic stem cells (ESCs) will help to uncover or further define signaling pathways and molecular mechanisms involved in the maintenance of self-renewal and pluripotency. We employed a 2-DE-based proteomics approach to analyze human ESC line, Royan H5, in undifferentiated cells and different stages of spontaneous differentiation (days 3, 6, 12, and 20) by embryoid body formation. Out of 945 proteins reproducibly detected on gels, the expression of 96 spots changed during differentiation. Using MS, 87 ESC-associated proteins were identified including several proteins involved in cell proliferation, cell apoptosis, transcription, translation, mRNA processing, and protein folding. Transcriptional changes accompanying differentiation of Royan H5 were also analyzed using microarrays. We developed a comprehensive data set that shows the use of human ESC lines in vitro to mimic gastrulation and organogenesis. Our results showed that proteomics and transcriptomics data are complementary rather than duplicative. Although regulation of many genes during differentiation were observed only at transcript level, modulation of several proteins was revealed only by proteome analysis.