Dependability of IT Systems in Emergency Situations – Theory and Practice

As our dependence on IT systems increases, evaluating the dependability of critical IT systems becomes more important. One of the main challenges in software reliability engineering is the sensitivity of software systems to a changing usage. This is especially important for systems that are critical in the aftermath of a crisis and for which reliability is the most important aspect of dependability. The crisis might change the usage of the system, and this could have a negative effect on the reliability. Because crisis situations are typically rare events, both the reliability and the criticality of IT systems after a crisis situation are hard to predict. The first part of this thesis focuses on the analysis of the sensitivity of the reliability of IT systems to changes in their usage. With the help of statistical methods the effects of changing usage profiles, modelled through the use of Markov models, can be examined. After a theoretical derivation of the properties of different models for the usage of software systems, the results were validated by applying the models to the data collected from the logfiles of a webserver. Swedish municipalities also depend more and more on IT systems for their daily work. Because of their important role in the relief coordination after a crisis, the dependability of their IT systems during these emergency situations is especially critical. The evaluation of this dependability requires the combination of two kinds of information: how critically needed the IT systems are in the aftermath of a crisis and how trustworthy the critical systems are. To avoid that a failing IT system disturbs the relief work, risk and vulnerability analyses need to take into account the dependability of critical IT systems. This way, municipalities can make sure that the relief work is not critically dependent on systems that are not sufficiently reliable. The second part of this thesis describes a case study on how two Swedish municipalities deal with these issues. The study focuses especially on the division of responsibilities in the municipalities and on their current methods. The study shows that today there is much room for improvement, especially in the communication between IT personnel and emergency managers. The main goal of these case studies is to form a basis for the development of practical methods that can assist Swedish municipalities in evaluating the dependability of their IT systems and integration of this information in their emergency planning in the near future

Dependable Digitally-Assisted Mixed-Signal IPs Based on Integrated Self-Test & Self-Calibration

Heterogeneous SoC devices, including sensors, analogue and mixed-signal front-end circuits and the availability of massive digital processing capability, are being increasingly used in safety-critical applications like in the automotive, medical, and the security arena. Already a significant amount of attention has been paid in literature with respect to the dependability of the digital parts in heterogeneous SoCs. This is in contrast to especially the sensors and front-end mixed-signal electronics; these are however particular sensitive to external influences over time and hence determining their dependability. This paper provides an integrated SoC/IP approach to enhance the dependability. It will give an example of a digitally-assisted mixed-signal front-end IP which is being evaluated under its mission profile of an automotive tyre pressure monitoring system. It will be shown how internal monitoring and digitally-controlled adaptation by using embedded processors can help in terms of improving the dependability of this mixed-signal part under harsh conditions for a long time

Does a Novice Technician Produce Results Similar to That of an Experienced DXA Technician When Assessing Body Composition and Bone Mineral Density?

Dual energy X-ray absorptiometry is a commonly used clinical assessment tool for body composition and bone mineral density, which is gaining popularity in athletic cohorts. Results from body composition scans are useful for athletic populations to track training and nutritional interventions, whilst bone mineral density scans are valuable for athletes at risk of developing stress fractures due to low bone mineral density. However, no research has ascertained if a novice technician (accredited but not experienced) could produce similar results to an experienced technician. Two groups of recreational athletes were scanned, one by an experienced technician, one by a novice technician. All participants were scanned twice with repositioning between scans. The experienced technician\u27s reliability (ICC 0.989 - 0.998, percentage change in mean -0.01 - 0.10), precision (typical error as CV% 0.01 to 0.47. standard error of measurement percentage 0.61% - 1.39%) and sensitivity to change (smallest real difference percentage 1.70% - 3.85%) were similar, however superior, to those of the novice technician. The novice technician results were: reliability (ICC 0.985 - 0.997, percentage change in mean -0.03 - 0.23), precision (typical error as CV% 0.03 - 0.75%, standard error of measurement percentage 1.06% - 2.12%) and sensitivity to change (smallest real difference percentage 2.73% - 5.86%). Extensive experience whilst valuable is not a necessary requirement to produce quality results when undertaking whole body dual energy X-ray absorptiometry scanning

Privacy In The Smart Grid: An Information Flow Analysis

Project Final Report prepared for CIEE and California Energy Commissio

Generic approach for deriving reliability and maintenance requirements through consideration of in-context customer objectives

Not all implementations of reliability are equally effective at providing customer and user benefit. Random system failure with no prior warning or failure accommodation will have an immediate, usually adverse impact on operation. Nevertheless, this approach to reliability, implicit in measurements such as ‘failure rate’ and ‘MTBF’, is widely assumed without consideration of potential benefits of pro-active maintenance. Similarly, it is easy to assume that improved maintainability is always a good thing. However, maintainability is only one option available to reduce cost of ownership and reduce the impact of failure. This paper discusses a process for deriving optimised reliability and maintenance requirements through consideration of in-context customer objectives rather than a product in isolation

Breaking the prejudice habit: Mechanisms, timecourse, and longevity

The prejudice habit-breaking intervention (Devine et al., 2012) and its offshoots (e.g., Carnes et al., 2012) have shown promise in effecting long-term change in key outcomes related to intergroup bias, including increases in awareness, concern about discrimination, and, in one study, long-term decreases in implicit bias. This intervention is based on the premise that unintentional bias is like a habit that can be broken with sufficient motivation, awareness, and effort. We conducted replication of the original habit-breaking intervention experiment in a sample more than three times the size of the original (N = 292). We also measured all outcomes every other day for 14 days and measured potential mechanisms for the intervention’s effects. Consistent with previous results, the habit-breaking intervention produced a change in concern that endured two weeks post-intervention. These effects were associated with increased sensitivity to the biases of others and an increased tendency to label biases as wrong. Contrasting with the original work, both control and intervention participants decreased in implicit bias, and the effects of the habit-breaking intervention on awareness declined in the second week of the study. In a subsample recruited two years later, intervention participants were more likely than control participants to object on a public online forum to an essay endorsing racial stereotyping. Our results suggest that the habit-breaking intervention produces enduring changes in peoples’ knowledge of and beliefs about race-related issues, and we argue that these changes are even more important for promoting long-term behavioral change than are changes in implicit bias

Space and Time: Wind in an Investment Planning Model

Investment planning models inform investment decisions and government policies. Current models do not capture the intermittent nature of renewable energy sources, restricting the applicability of the models for high penetrations of renewables. We provide a methodology to capture spatial variation in wind output in combination with transmission constraints. The representation of wind distributions with stochastic approaches or an extensive historic data set would exceed computational constraints for real world application. Hence we restrict the amount of input data, and use boot-strapping to illustrate the robustness of the results. For the UK power system we model wind deployment and the value of transmission capacity