Quantitative verification of gossip protocols for certificate transparency

Certificate transparency is a promising solution to publicly auditing Internet certificates. However, there is the potential of split-world attacks, where users are directed to fake versions of the log where they may accept fraudulent certificates. To ensure users are seeing the same version of a log, gossip protocols have been designed where users share and verify log-generated data. This thesis proposes a methodology of evaluating such protocols using probabilistic model checking, a collection of techniques for formally verifying properties of stochastic systems. It also describes the approach to modelling and verifying the protocols and analysing several aspects, including the success rate of detecting inconsistencies in gossip messages and its efficiency in terms of bandwidth. This thesis also compares different protocol variants and suggests ways to augment the protocol to improve performances, using model checking to verify the claims. To address uncertainty and unscalability issues within the models, this thesis shows how to transform models by allowing the probability of certain events to lie within a range of values, and abstract them to make the verification process more efficient. Lastly, by parameterising the models, this thesis shows how to search possible model configurations to find the worst-case behaviour for certain formal properties

Relationships between Motor Competence, Physical Activity, and Obesity in British Preschool Aged Children

Background: This cross-sectional study aimed to examine associations between motor competence, physical activity, and obesity in British children aged three to five years. Method: Motor competence (MC) was assessed using the Test of Gross Motor Development-2. Physical activity (PA) was assessed using triaxial wrist-worn accelerometers. Children were assessed on compliance to current PA recommendations of ≥180 min of total PA (TPA) and ≥60 min of moderate-to-vigorous PA (MVPA) for health benefits. Associations were explored with Pearson’s product moments and weight-status, and sex-differences were explored with independent t-tests and chi-squared analysis. Results: A total of 166 children (55% males; 4.28 ± 0.74 years) completed MC and PA assessments. Associations were found between PA and MC (TPA and overall MC, TPA and object-control MC (OC), MVPA and overall MC, and MVPA and OC). This study suggests that good motor competence is an important correlate of children meeting physical activity guidelines for health

The Effects of a 6-Week Swimming Intervention on Gross Motor Development in Primary School Children

(1) Background: This study examines the effects of a 6-week swimming intervention on motor competence in children. (2) Methods: A total of 107 children (n = 52 boys, n = 55 girls) aged 7.8 ± 0.63 years that were recruited from five primary schools in central England participated in this study, undertaking either an aquatic intervention once a week for six weeks or acting as a control group completing their usual physical education program. Participants underwent pre- and post-assessments of general motor competence using the Test of Gross Motor Development, Third Edition (TGMD-3) (a process measure) and a composite of 10 m running sprint time and standing long jump distance (product measures). Aquatic motor competence was assessed via the Aquatic Movement Protocol (AMP). Fear of drowning and swimming opportunities were also assessed by implementing a questionnaire. (3) Results: Following a mixed-model ANOVA, an overall main effect was found from pre (40.05 ± 13.6) to post (48.3 ± 18.6) for TGMD-3 scores (p < 0.05) and pre (38.7 ± 31.7) to post (50.6 ± 36.8) for AMP scores (p = 0.001). A negative significant relationship was found between AMP scores with both fear of water (p = 0.01) and fear of drowning (p < 0.05). A positive significant relationship was found between swimming opportunities and AMP score (p = 0.001). (4) Conclusions: The aquatic-based intervention improves not only aquatic motor competence but also transfers improvements in dryland movement competencies. Future research should look to implement control groupings which do not participate in swimming to further investigate the difference between swimmers and non-swimmers; however, due to swimming being a part of the national curriculum in England, this may not be feasible

Anti-Corruption Law in Local Government: Legal Issues related to Ordinance-Design and Municipal-Level Anti-Corruption Agencies in Macedonia

Macedonian municipalities should pass anti-corruption ordinances in order to reduce corruption. The paper reviews the legal issues involved in drafting such ordinances and provides legal advisors to local councils with the legal and economic analysis needed to tackle some of the more difficult and detailed questions. The most important issue revolves around the creation of a model ordinance which Macedonian municipalities (or the Association of Units of Local Self-Government of the Republic of Macedonia) could adopt in order to set-up and run municipal-level anti-corruption agencies. The location of such agencies as well as their competencies (to monitor conflicts of interests, oversee asset declarations, and conduct corruption risk-audits among others ) are analysed. The paper also provides legal interpretations of Macedonian legislation and their likely impact on municipal council ordinance design in the area of anti-corruption - providing the legal basis for positive administrative silence, the splitting of municipal procurement contracts, and (most controversially) qui tam rewards at the municipal level. A brief regulatory impact analysis of the ordinance shows a gain of Euro 162,900 in social welfare if such a programme were rolled-out in Macedonia.