STPA (System-Theoretic Process Analysis) is a new hazard analysis technique which builds on STAMP, a process and accident model using concepts of system and control theory. In this paper, we present A-STPA an open tool to help transform STPA to an executable STPA which automates the activities of STPA. We develop the A-STPA tool to assist safety analysts in performing STPA. Moreover, it will gi...

StpA has functional similarity to its homologue, the nucleoid structuring protein H-NS. It binds to AT-rich, planar, bent DNA and constrains DNA supercoils. In addition, StpA acts as an RNA chaperone. StpA and H-NS also form heterodimers. However, cellular levels of StpA are low due to repression of stpA by H-NS and negative autoregulation. Here we show that effective (30-fold) repression of st...

The nucleoid-associated proteins H-NS and StpA in Escherichia coli bind DNA as oligomers and are implicated in gene regulatory systems. There is evidence for both homomeric and heteromeric H-NS-StpA complexes. The two proteins show differential turnover, and StpA was previously found to be subject to protease-mediated degradation by the Lon protease. We investigated which regions of the H-NS pr...

STPA (Systems-Theoretic Processes Analysis) is a new hazard analysis technique based on STAMP. STPA is already being used in different industrial domains (e.g. space, aviation, medical or automotive). To support the application of STPA and make using STPA more efficient, we developed an open tool called A-STPA. However, the current usage of ASTPA by safety analysts in different areas shows a nu...

The Escherichia coli proteins H-NS is recognized as an important component among the major nucleoid-associated proteins. In studies of E. coli strains with defects in H-NS, we discovered a mutant that phenotypically restored stationary-phase viability (Rsv) of such strains. The Rsv phenotype was the result of a mutation that led to severalfold higher levels of the functionally and structurally ...

As the uses of software are various, software is germane to human's life and property. Thus, the importance of software safety increases rapidly and many hazard analysis techniques are used for safety of system/software. STAMP/STPA is an efficient hazard analysis technique for large and complex system. But subject of STAMP/STPA is system, not software. This difference of subjects makes difficul...

Hazard analysis is one of the most important elements in developing safe-critical systems. STPA (SystemsTheoretic Process Analysis) is a modern technique based on the new accident causation model STAMP (System-Theoretic Accident Model and Process) for analyzing hazard and safety issues, which can be applied early in the design process of a system to achieve an acceptable risk level. We have app...

The nucleoid-associated protein H-NS is important for gene regulation in Escherichia coli. We have studied H-NS interaction with StpA and an uncharacterized H-NS-like protein, Hfp, in the uropathogenic E. coli isolate 536 that expresses all three nucleoid-associated proteins. We found distinct interactions of the three proteins at the protein level, resulting in the formation of heteromers, as ...

XSTAMPP (eXtensible STAMP Platform ) is a software tool developed to serve the widespread adoption and use of STAMP methodologies in different domains. The first version of XSTAMPP supported only the STPA application. In this paper, we present a new version of XSTAMPP, including CAST accident analysis and extended approach to STPA. We developed two new plug-in tools called (1) A-CAST (Automated...

Twelve different dominant negative mutants of the Escherichia coli nucleoid-associated protein, H-NS, have been selected and characterized in vivo. The mutants are all severely defective in promoter repression activity in a strain lacking H-NS, and they all disrupt the repression normally exerted by H-NS at two of its target promoters. From the locations of the alterations in these mutants, whi...