Continuous-discrete multiple target tracking with out-of-sequence measurements

This paper derives the optimal Bayesian processing of an out-of-sequence (OOS) set of measurements in continuous-time for multiple target tracking. We consider a multi-target system modelled in continuous time that is discretised at the time steps when we receive the measurements, which are distributed according to the standard point target model. All information about this system at the sampled time steps is provided by the posterior density on the set of all trajectories. This density can be computed via the continuous-discrete trajectory Poisson multi-Bernoulli mixture (TPMBM) filter. When we receive an OOS measurement, the optimal Bayesian processing performs a retrodiction step that adds trajectory information at the OOS measurement time stamp followed by an update step. After the OOS measurement update, the posterior remains in TPMBM form. We also provide a computationally lighter alternative based on a trajectory Poisson multi-Bernoulli filter. The effectiveness of the two approaches to handle OOS measurements is evaluated via simulations

Un-learning 'community': reflections on socio-technical spatial design support with Slovo Park

The South African city we experience today did not simply manifest in a vacuum outside of the social injustice of the last 400+ years of colonial and Apartheid ‘development’. The four-hour commute that the average Johannesburg city user experiences, the sense of fractured locality across the metropolitans of Durban and Pretoria and the intact socio-economic segregation of townships to suburbs seen in Cape Town are all the tangible legacies of the Apartheid city design that we complicity accept as our South African city on a daily basis. The knee-jerk reaction by built environment practitioners to this observation is typically a technocratic response to suggest an addition of infrastructure and implementation and not a reform of the practice of city-making. The fact remains that among the large-scale projects our democratic government has implemented we sit with infrastructure deficits larger today than 1994. The practice of ‘making city’ in South Africa requires some form of radical change, one that calls on all city makers to re-conceptualise how we see, make and manage our spaces. While technical skills and competencies are vital to this approach, the immediate challenge for built environment practitioners can be seen in the lack of skills or willingness of individuals and institutions to engage with the socio-political complexity of our cities. The misnomer that we are dealing with a homogenous technical challenge for a homogenous social demographic of people (or the ‘community’) that can be solved through a ‘better house/shack/dwelling’, a more efficient toilet system or solar panel array, is damaging and criminally myopic in its lack of imagination, creativity or recognition of the situation. The paper offers a structured reflection on an eight-year case study conducted by the author and his colleagues. The argument of the paper is centred around a critique on the often-misused terms of ‘informality’, community’, ‘participation’ and ‘development’ in the built environment sector of spatial development. The case study unpacks the approach and methods used within the Socio-Technical Spatial Design practice of ‘Neighbourhood Making’ and offers a reflection on critical skills and lessons gathered from the experience. The intent of this reflexive study is to offer a working reference for privatesector practitioners, government officials and grassroots practitioners who are looking to engage informal neighbourhood upgrading in South Africa

Out-of-School Time Policy Commentary #1: Out-of-School Research Meets After-School Policy

The past five years have seen a ground swell in public attention and public policy aimed at increasing the availability of after-school programs for children and young teens during the "risk" hours when safety, supervision and homework are of top concern. Popularly called "after-school," these programs represent a new and growing variation on the broader group of out-of-school time programs and opportunities that have been around for decades -- programs ranging from youth orchestras to soccer leagues that reach children and older teens. What does research tell us about after-school programs? What outcomes are realistic? What practices are essential? What changes are measurable? How does the call for scientifically-based research fit into the picture? In the first of a series of policy briefs focused on out-of-school time issues, Deborah Vandell, a leading researcher on after-school programs, gives a walking tour of the research. Kerry Mazzoni, California Secretary of Education, shares her perspectives on how research influences policy

UA52/1 Out of the Box

Newsletter created by and about WKU Archives, the records management program and TopScholar administration

UA52/1 Out of the Box

Newsletter created by and about WKU Archives and the records management program

UA52/1 Out of the Box

Newsletter created by and about WKU Archives and the records management program

Out-of-hospital cardiac arrest due to idiopathic ventricular fibrillation in patients with normal electrocardiograms:results from a multicentre long-term registry

AIMS : To define the clinical characteristics and long-term clinical outcomes of a large cohort of patients with idiopathic ventricular fibrillation (IVF) and normal 12-lead electrocardiograms (ECGs). METHODS AND RESULTS: Patients with ventricular fibrillation as the presenting rhythm, normal baseline, and follow-up ECGs with no signs of cardiac channelopathy including early repolarization or atrioventricular conduction abnormalities, and without structural heart disease were included in a registry. A total of 245 patients (median age: 38 years; males 59%) were recruited from 25 centres. An implantable cardioverter-defibrillator (ICD) was implanted in 226 patients (92%), while 18 patients (8%) were treated with drug therapy only. Over a median follow-up of 63 months (interquartile range: 25-110 months), 12 patients died (5%); in four of them (1.6%) the lethal event was of cardiac origin. Patients treated with antiarrhythmic drugs only had a higher rate of cardiovascular death compared to patients who received an ICD (16% vs. 0.4%, P = 0.001). Fifty-two patients (21%) experienced an arrhythmic recurrence. Age ≤16 years at the time of the first ventricular arrhythmia was the only predictor of arrhythmic recurrence on multivariable analysis [hazard ratio (HR) 0.41, 95% confidence interval (CI) 0.18-0.92; P = 0.03]. CONCLUSION : Patients with IVF and persistently normal ECGs frequently have arrhythmic recurrences, but a good prognosis when treated with an ICD. Children are a category of IVF patients at higher risk of arrhythmic recurrences

Reliability modeling of a 1-out-of-2 system: Research with diverse Off-the-shelf SQL database servers

Fault tolerance via design diversity is often the only viable way of achieving sufficient dependability levels when using off-the-shelf components. We have reported previously on studies with bug reports of four open-source and commercial off-the-shelf database servers and later release of two of them. The results were very promising for designers of fault-tolerant solutions that wish to employ diverse servers: very few bugs caused failures in more than one server and none caused failure in more than two. In this paper we offer details of two approaches we have studied to construct reliability growth models for a 1-out-of-2 fault-tolerant server which utilize the bug reports. The models presented are of practical significance to system designers wishing to employ diversity with off-the-shelf components since often the bug reports are the only direct dependability evidence available to them