Virtual Button and Graphical Interface System Safety Evaluation using System Theoretic Process Analysis (STPA)

System Theoretic Process Analysis (STPA) is an extremely valuable methodology, especially when used early in a system’s concept phase, for effective and efficient development of safety requirements that address potential safety issues associated with human machine interactions. This paper outlines how STPA can be used to explore potential safety concerns associated with interactions between human operators and virtual buttons within graphical interfaces across the planned operational scenarios and expected system behaviors. Appropriately validated system safety requirements can be developed based on this exploratory effort. The paper shows how STPA includes drivers and operators as system elements within the control structure where these humans are expected to interact with a “system/feature of interest” by means of virtual buttons presented in a graphical interface. The inclusion of humans as elements of the control structure enables a representation of the human as a “human controller” and, as such, enables STPA evaluation techniques to be applied to them just as these techniques would be applied to any “control” element in a control structure

Working with religious and spiritual athletes: ethical considerations for sport psychologists

With a growing number of sport performers revealing their religious and spiritual beliefs, it is becoming increasingly important for sport psychologists to recognize and appreciate the values (and value systems) to which such beliefs are attached. Using the RRICC model (Plante, 2007) as a framework for discussion, and through the lens of cultural praxis, the purpose of this article is to highlight ethical issues for sport psychologists when working with religious and spiritual athletes. The RRICC model addresses the ethical principles of respect, responsibility, integrity, competence, and concern. It is hoped that a discussion of these guidelines will help sport psychologists better navigate the often challenging landscape of working with athletes whose everyday lives and identities are grounded in religious and spiritual association

Increase in perceived case suspiciousness due to local contrast optimisation in digital screening mammography

Item does not contain fulltextOBJECTIVES: To determine the influence of local contrast optimisation on diagnostic accuracy and perceived suspiciousness of digital screening mammograms. METHODS: Data were collected from a screening region in the Netherlands and consisted of 263 digital screening cases (153 recalled,110 normal). Each case was available twice, once processed with a tissue equalisation (TE) algorithm and once with local contrast optimisation (PV). All cases had digitised previous mammograms. For both algorithms, the probability of malignancy of each finding was scored independently by six screening radiologists. Perceived case suspiciousness was defined as the highest probability of malignancy of all findings of a radiologist within a case. Differences in diagnostic accuracy of the processing algorithms were analysed by comparing the areas under the receiver operating characteristic curves (A(z)). Differences in perceived case suspiciousness were analysed using sign tests. RESULTS: There was no significant difference in A(z) (TE: 0.909, PV 0.917, P = 0.46). For all radiologists, perceived case suspiciousness using PV was higher than using TE more often than vice versa (ratio: 1.14-2.12). This was significant (P <0.0083) for four radiologists. CONCLUSIONS: Optimisation of local contrast by image processing may increase perceived case suspiciousness, while diagnostic accuracy may remain similar. KEY POINTS: Variations among different image processing algorithms for digital screening mammography are large. Current algorithms still aim for optimal local contrast with a low dynamic range. Although optimisation of contrast may increase sensitivity, diagnostic accuracy is probably unchanged. Increased local contrast may render both normal and abnormal structures more conspicuous.1 april 201

The SPARC Toroidal Field Model Coil Program

The SPARC Toroidal Field Model Coil (TFMC) Program was a three-year effort between 2018 and 2021 that developed novel Rare Earth Yttrium Barium Copper Oxide (REBCO) superconductor technologies and then successfully utilized these technologies to design, build, and test a first-in-class, high-field (~20 T), representative-scale (~3 m) superconducting toroidal field coil. With the principal objective of demonstrating mature, large-scale, REBCO magnets, the project was executed jointly by the MIT Plasma Science and Fusion Center (PSFC) and Commonwealth Fusion Systems (CFS). The TFMC achieved its programmatic goal of experimentally demonstrating a large-scale high-field REBCO magnet, achieving 20.1 T peak field-on-conductor with 40.5 kA of terminal current, 815 kN/m of Lorentz loading on the REBCO stacks, and almost 1 GPa of mechanical stress accommodated by the structural case. Fifteen internal demountable pancake-to-pancake joints operated in the 0.5 to 2.0 nOhm range at 20 K and in magnetic fields up to 12 T. The DC and AC electromagnetic performance of the magnet, predicted by new advances in high-fidelity computational models, was confirmed in two test campaigns while the massively parallel, single-pass, pressure-vessel style coolant scheme capable of large heat removal was validated. The REBCO current lead and feeder system was experimentally qualified up to 50 kA, and the crycooler based cryogenic system provided 600 W of cooling power at 20 K with mass flow rates up to 70 g/s at a maximum design pressure of 20 bar-a for the test campaigns. Finally, the feasibility of using passive, self-protection against a quench in a fusion-scale NI TF coil was experimentally assessed with an intentional open-circuit quench at 31.5 kA terminal current.Comment: 17 pages 9 figures, overview paper and the first of a six-part series of papers covering the TFMC Progra

The Effects of Microblogging in the Classroom on Communication

This study explored the integration of a microblogging platform, Twitter, into higher education, and how it affected the perceived communication between students and their professors and amongst students. McCroskey (1977) states every individual has a different communication apprehension score, which is a level of anxiety or fear one experiences when communication is anticipated. This research aims to relate this score to the change in communication perception. Data was gathered via surveys, interviews, and observations and was then analyzed using grounded theory methods presented by Strauss and Corbin (1990). The theory generated suggests individuals with average and lower communication apprehension scores had a better experience using Twitter and experienced more of a positive change in perceived communication. This suggests Twitter can be an effective teaching tool in higher education