Creating regional crime statistics from administrative data

Abstract: The only publicly-available information on the geographical distribution of crime in New Zealand is offence statistics for police administrative units. We investigate whether existing data can be used to construct geographical crime statistics that correspond to regional councils, territorial authorities, and urban areas. Methods We build experimental output geographies from police stations, the smallest administrative unit for which there are long time series of offence statistics. We develop three rules for assigning police stations to the new geographies: one based on population, one based on land area, and one based on both. We assess the performance of these rules by calculating the proportion of national land area and population that is misclassified, and the number of target units that do not receive at least one police station. We also look at whether regional statistics on serious assaults are sensitive to the choice of allocation rule. Findings The new output geographies approximate the target geographies well. For instance, our preferred rule assigns 96 percent of the national population to the correct territorial authority. Moreover, a case study of serious assaults suggests that most regional crime statistics are not sensitive to the choice of rule. Conclusion The new output geographies perform sufficiently well that they could, if required, be used to produce regional crime statistics

Adaptive Smoothing for Trajectory Reconstruction

Trajectory reconstruction is the process of inferring the path of a moving object between successive observations. In this paper, we propose a smoothing spline -- which we name the V-spline -- that incorporates position and velocity information and a penalty term that controls acceleration. We introduce a particular adaptive V-spline designed to control the impact of irregularly sampled observations and noisy velocity measurements. A cross-validation scheme for estimating the V-spline parameters is given and we detail the performance of the V-spline on four particularly challenging test datasets. Finally, an application of the V-spline to vehicle trajectory reconstruction in two dimensions is given, in which the penalty term is allowed to further depend on known operational characteristics of the vehicle.Comment: 25 pages, submitte

Victim Assistance Efforts: The Niagara Foot

A team of Canadian researchers and professionals has designed and tested a novel prosthetic foot tailored for active amputees in post-conflict regions

Development and validation of the child post-traumatic cognitions inventory (CPTCI)

Background: Negative trauma-related cognitions have been found to be a significant factor in the maintenance of post-traumatic stress disorder (PTSD) in adults. Initial studies of such appraisals in trauma-exposed children and adolescents suggest that this is an important line of research in youth, yet empirically validated measures for use with younger populations are lacking. A measure of negative trauma-related cognitions for use with children and adolescents, the Child Post-Traumatic Cognitions Inventory (CPTCI), is presented. The measure was devised as an age-appropriate version of the adult Post-Traumatic Cognitions Inventory (Foa et al., 1999). Methods: The CPTCI was developed and validated within a large (n = 570) sample, comprising community and trauma-exposed samples of children and adolescents aged 6-18 years. Results: Principal components analysis suggested a two-component structure. These components were labelled 'permanent and disturbing change' and 'fragile person in a scary world', and were each found to possess good internal consistency, test-retest reliability, convergent validity, and discriminative validity. The reliability and validity of these sub-scales was present regardless of whether the measure was completed in the acute phase or several months after a trauma. Scores on these sub-scales did not vary with age. Conclusions: The CPTCI is a reliable and valid measure that is not specific to the type of trauma exposure, and shows considerable promise as a research and clinical tool. The structure of this measure suggests that appraisals concerning the more abstract consequences of a trauma, as well as physical threat and vulnerability, are pertinent factors in trauma-exposed children and adolescents, even prepubescent children

Trustworthy Software : lessons from `goto fail' & Heartbleed bugs

In the first four months of 2014, two major vulnerabilities were announced affecting operation of the Transport Layer Security (TLS) protocol, which is used by applications to secure Internet communications. The `goto fail' bug affected Apple's iOS and OS X software and the `Heartbleed' bug affected versions of the OpenSSL software. Whilst the Apple bug was serious because it affected a wide range of Apple products, the Heartbleed bug was of greater significance due to widespread use of the OpenSSL library. This paper considers the lessons to be learned from these incidents. It examines how the use of the Trustworthy Software Framework (TSF) developed by the authors could have helped to reduce the risk of a major bugs like `goto fail' and Heartbleed. It also examines the responsibilities of developers where they use third party libraries and the need for appropriate due diligence. The paper also makes recommendations about how incidents like this should be handled to avoid confusing and contradictory messages being given

Adaptive Smoothing Spline for Trajectory Reconstruction

Trajectory reconstruction is the process of inferring the path of a moving object between successive observations. In this paper, we propose a smoothing spline -- which we name the V-spline -- that incorporates position and velocity information and a penalty term that controls acceleration. We introduce a particular adaptive V-spline designed to control the impact of irregularly sampled observations and noisy velocity measurements. A cross-validation scheme for estimating the V-spline parameters is given and we detail the performance of the V-spline on four particularly challenging test datasets. Finally, an application of the V-spline to vehicle trajectory reconstruction in two dimensions is given, in which the penalty term is allowed to further depend on known operational characteristics of the vehicle

Self-reported knee joint instability is related to passive mechanical stiffness in medial knee osteoarthritis

BACKGROUND: Self-reported knee joint instability compromises function in individuals with medial knee osteoarthritis and may be related to impaired joint mechanics. The purpose of this study was to evaluate the relationship between self-reported instability and the passive varus-valgus mechanical behaviour of the medial osteoarthritis knee. METHODS: Passive varus-valgus angular laxity and stiffness were assessed using a modified isokinetic dynamometer in 73 participants with medial tibiofemoral osteoarthritis. All participants self-reported the absence or presence of knee instability symptoms and the degree to which instability affected daily activity on a 6-point likert scale. RESULTS: Forward linear regression modelling identified a significant inverse relationship between passive mid-range knee stiffness and symptoms of knee instability (r = 0.27; P < 0.05): reduced stiffness was indicative of more severe instability symptoms. Angular laxity and end-range stiffness were not related to instability symptoms (P > 0.05). CONCLUSIONS: Conceivably, a stiffer passive system may contribute toward greater joint stability during functional activities. Importantly however, net joint stiffness is influenced by both active and passive stiffness, and thus the active neuromuscular system may compensate for reduced passive stiffness in order to maintain joint stability. Future work is merited to examine the role of active stiffness in symptomatic joint stability