A systematical Bayesian approach for outcome-oriented fire service data collection

Data collection is always related to costs and to investments of resources. Especially data collected by the fire services is often not collected in a systematic manner and often without a clear purpose. A more systematic approach is achieved by identifying the stakeholders or decision-makers who are intended to use or benefit from the data and bear the costs. Whether a survey is reasonable or not can be treated in the context of a decision-problem by performing a pre-posterior decision analysis in order to assess the value of information. Potential stakeholders are identified that can benefit from fire service data and an overview is provided on the type of information that can be obtained by a survey or information that results from engineering knowledge. Both information are associated with uncertainties and should be identified and quantified before the data is collected to limit the extent of the collection process. A hierarchical Bayesian probabilistic approach is proposed to combine both type of information by differentiate the uncertainties between aleatory and epistemic uncertainties. The data can be used to update epistemic uncertainties by applying Bayesian inference techniques. An example for the estimation of fire service intervention characteristics illustrates the approach and discusses how aleatory and epistemic uncertainties can be quantified.     

Real-time “Sense-and-Act” operation for construction robots

A new concept of real-time “Sense-and-Act” operation is presented for mobile construction robots performing accurate and/or delicate tasks. The concept enables an indoor mobile robot to be positioned merely in the vicinity of its temporary workstation, with an approximate accuracy of about 10 cm. The robot then calibrates itself to the immediate environment relevant only to the current workstation. The movements made by the robot's end-tool, when bringing a building element to its target position, are directed in real-time by sensing the tool's immediate surroundings. The overall task cycle starts with a swift long-distance movement of the arm towards the target, followed by a series of fine, short-distance, iterative, “Sense-and-Act” cycles. This constant interaction with the immediate environment renders unimportant many errors that may occur in the broader environment. This concept was applied to tile setting on walls, one of the most challenging interior tasks for construction robots, which requires three-dimensional precision to the millimeter. A special device, based on a CCD camera and several laser projectors, combined with computer image processing, was developed for the delicate “Sense-and-Act” cycles. This device is also introduced and discussed in the paper, along with a presentation and analysis of full-scale tile setting experiments.     

Municipalities and the “new” internationalism: Cautionary notes from Canada

This study attempts to assess the impact of municipal internationalism for cities and towns involved in more comprehensive types of global interchange. Focusing on two Canadian-sponsored linkages — involving the cities of Lethbridge (Alberta) and Ica (Peru), and Toronto (Ontario) and São Paulo (Brazil), respectively — the study supports the findings of earlier research which reveals that intensive municipal exchange can pay real dividends to the participants involved. At the same time, however, closer examination of exchange dynamics in each case shows that the process can also produce certain unintended — and negative — consequences not previously identified in the literature. These, in turn, appear to affect not only the quality of specific projects, but the continued vitality of the exchange process itself — thus limiting the overall benefits of the phenomenon.     

Bayesian analysis of the T-year events for flood data fitted by a three-parameter lognormal distribution

The three-parameter lognormal distribution is widely used in hydrology to fit maximum annual flood events. The method most commonly used to estimate the parameters and 7”-year flood event is the method of maximum likelihood. In this paper, Bayes estimates of the parameters and of the 7”-yearflood and their posterior variances of estimates are obtained by using Lindley's Bayesian approximation procedure. These estimates are then compared to estimates obtained by the method of maximum likelihood. Twelve flood series from all over Canada that are shown to be well-fitted by the three-parameter lognormal distribution are used as numerical examples. In all cases the posterior variances of the Bayes estimates of the 7”-year flood events are less than the corresponding variances of their maximum likelihood counterparts.     

Risk assessment of “down-the-drain” chemicals: Search for a suitable model

Legal and regulatory authorities around the world generally require that risk assessments are undertaken for the licensing of new and existing substances that present high risk to the environment or the human health. This applies to ‘down-the-drain’ chemicals that are usually found in household products, such as detergents, that are mainly discharged into rivers via sewer systems. However, the data available for these chemicals is often limited due to cost constraints: in particular, concentration time series for works effluent are generally unavailable, even load data for specific works is often scarce.Although a wide range of models are available, there is a general lack of knowledge on their suitability to model the fate of down-the-drain chemicals at the catchment scale. Several models are presented in this review. The models selected are: the Mackay models, EUSES, Mike 11, QUAL2E, TOMCAT and GREAT-ER. Various applications of these models were investigated to investigate their strength and weaknesses. It appears that, where the availability of data is limited, multimedia fate models such as the Mackay models and EUSES may best be applied to estimate the global risk within each media. However, for site-specific risk assessment the GREAT-ER in-stream water quality model was considered to be more appropriate for modelling down-the-drain chemicals, because it accounts for both spatial and temporal variability, while its data requirements are lower than for models such as Mike 11 and QUAL2E.     

Predicting the ultimate bending capacity of concrete beams from the “relaxation ratio” analysis of AE signals

This paper presents an alternative approach to the problem, based on “testing” the real structure rather than trying to model it. Experiments on reinforced concrete (RC) beams, representative of bridge beams, are described. The beams were loaded in cycles up to failure whilst recording the acoustic emissions (AE) generated. The analysis of the AE signals was then undertaken based on a proposed new parameter, named the “relaxation ratio”. This quantifies the AE energy recorded during the unloading and loading phases of a cycle test and it showed a clear correlation with the bending failure load of the RC beams. A change in trend was noted when the load reached approximately the 45% of the ultimate bending load. The results appeared to be influenced by factors such as the concrete strength and loading rate and further work is needed to extend the results to full scale testing of bridge beams.     

A subsurface “drift and pile” protection scheme for the construction of a shallow metro tunnel

In the construction of a shallow running-tunnel for Beijing metro line No. 13, due to restrictions by the surface environment of the area, a subsurface protection scheme was applied: two small cross-section drifts with shotcrete linings were constructed at above each side of the subway running tunnel, and reinforced concrete piles were installed into the ground from within the drifts. The piles were rigidly connected with the floor slabs of the drift linings, so that the drifts could effectively help extend the height of the protected zone of ground. With no disturbance to the normal living of the residents in the area, the major objective of the scheme was to separate the negative effects of tunneling on two nearby high-rise residential buildings, one at each side of the tunnel, respectively. Relating to the scheme, this paper presents the relevant site conditions, design concepts and analyses, constructions and monitoring highlights.     

“Danger lurks around every corner”: Fear of Crime and its Impact on Opportunities for Social Interaction in Stigmatised Australian Suburbs

This article examines some of the ways in which fear of crime impacts upon opportunities for social interaction among residents in stigmatised suburbs. As we explore in this article, neighbourhoods that are stigmatised by virtue of material disadvantage and poor reputations tend to be associated with a number of social problems, including higher rates of crime. This association with crime, our research suggests, has an impact on social interaction in these neighbourhoods. Specifically, fear of crime may make people less likely to draw on forms of social interaction which enable people to build trust through contact with their fellow residents. In developing this position, the article draws on qualitative data detailing residents' perceptions of safety in three neighbourhoods in Adelaide, South Australia, two of which are stigmatised as 'problem neighbourhoods'. The article concludes by considering the public policy implications that arise from the research.