Multicriteria methods and logic aggregation in suitability maps

In this paper, we identify and describe fundamental logic properties of multicriteria methods for land‐use suitability analysis and the design of suitability maps. The existing multicriteria methods can be evaluated from the standpoint of their ability to support the necessary logic properties that affect the expressive power of evaluation methods. The paper investigates and compares simple additive scoring, multiattribute value technique, multiattribute utility technique, analytic hierarchy process, ordered weighted average, outranking methods, and logic scoring of preference (LSP). We introduce canonical forms of logic aggregation in suitability maps and show how to use canonical aggregation structures to design LSP suitability maps that evaluate distributions of points of interests (POIs) in urban areas. © 2011 Wiley Periodicals, Inc.     

Detection and correction of specular reflections for automatic surgical tool segmentation in thoracoscopic images

This paper presents an algorithm that automatically detects and corrects specular reflections in thoracoscopic images and its application in the context of automatic segmentation of surgical tools. The detection is done by isolating the spike component of the specular reflection which is characterized by a bump at the end of the histogram of thoracoscopic images. The specular lobe is then extracted in the neighborhood of the spike component of the reflection. The result is a mask of the reflections positions in the image. Thereafter, the image is corrected using Oliveira et al.’s digital inpainting method. The automatic segmentation of surgical tools using the corrected images is then demonstrated. Results of the segmentation with and without the specular reflection elimination technique are compared. Moreover, 108 images extracted from 5 different surgeries performed under various conditions were considered to demonstrate the effectiveness of the proposed technique.     

Not All Autonomy is the Same. Different Dimensions of Job Autonomy and Their Relation to Work Engagement & Innovative Work Behavior

Job autonomy is a key enabling factor for employee engagement and innovative employee behavior. Although job autonomy used to be viewed as a multi‐dimensional construct, there has been little recent discussion on the different dimensions of job autonomy and how they relate to employee outcomes. This study uses a sample of 927 employees from different sectors to research the relation between autonomy regarding the (1) work method, (2) work scheduling, (3) work time and (4) place of work and two main employee outcomes: work engagement (WE) and innovative work behavior (IWB). The results show that all studied dimensions of autonomy are bivariatly related to higher levels of WE and IWB. Yet, when simultaneously analyzing the dimensions of job autonomy using structural equations modelling, most of the effects become insignificant. For WE, only the effect of work method autonomy is statistically significant. For IWB, work method and locational autonomy play a positive role. This signals that the current managerial attention for, e.g., work time autonomy (flexitime) does only contribute to enhanced work engagement and IWB insofar as such a systems result in higher work method autonomy.     

Ray Specialized Contraction on Bounding Volume Hierarchies

In this paper we propose a simple but effective method to modify a BVH based on ray distribution for improved ray tracing performance. Our method starts with an initial BVH generated by any state‐of‐the‐art offline algorithm. Then by traversing a small set of sample rays we collect statistics at each node of the BVH. Finally, a simple but ultra‐fast BVH contraction algorithm modifies the initial binary BVH to a multi‐way BVH. The overall acceleration for ray‐primitive testing is about 25% for incoherent diffuse rays and 30% for shadow rays, which is significant as a data structure optimization. Similar results are also presented for packet ray tracing, and for Quad‐BVHs the improvement is 10% to 15%. The approach has the advantages of being simple, and compatible with almost any existing BVH and ray tracing techniques, and it require very little extra work to generate the modified tree.     

Does advanced driver training improve situational awareness?

Over 70 years of experiential evidence suggests that a specific form of advanced driver training, one based on an explicit system of car control, improves driver situation awareness (SA). Five experimental hypotheses are developed. They propose that advanced driving should increase the number of information elements in the driver's working memory, increase the interconnection between those elements, increase the amount of ‘new’ information in memory as well as the prominence of existing information, and that finally, it should stimulate behaviours that help drivers evolve better situations to be aware of. An approach to SA based on Neisser's perceptual cycle theory is anchored to a network based methodology. This is applied within the context of a longitudinal on-road study involving three groups of 25 drivers, all of whom were measured pre- and post-intervention. One experimental group was subject to advanced driver training and two further groups provided control for time and for being accompanied whilst driving. Empirical support is found for all five hypotheses. Advanced driving does improve driver SA but not necessarily in the way that existing situation focused, closed loop models of the concept might predict.     

Assessment of the relationship between the international roughness index and dynamic loading of heavy vehicles

Due to imperfect surface profiles, heavy vehicles moving at high speed on flexible pavement structures oscillate in the vertical axis. This phenomenon induces dynamic loads, which oscillate at lower and higher values than the average load associated with static load considered with most pavement analysis and design applications. Higher loads applied to flexible pavements are likely to significantly reduce pavement service life. A new multibody dynamic truck model was used to study heavy vehicle wheel load for various pavement profiles of varying international roughness index (IRI). The modelled heavy vehicle wheel load response were used to calculate the dynamic load coefficient, and a relationship with IRI was proposed. On the basis of this relationship, the evolving pavement surface profile, and thus evolving IRI, was used to determine the evolution of dynamic loading with pavement life. A comparison of pavement service life for the classical static loading and for dynamic loading was made for three highway flexible pavement structures. When dynamic loads are considered, it was found that the pavement service life reduction may be reduced of about 29 and 20% for bottom-up fatigue cracking and structural rutting failure criteria.     

Model-based development of a course of action scheduling tool

This paper shows how a formal method in the form of Coloured Petri Nets (CPNs) and the supporting CPN Tools have been used in the development of the Course of Action Scheduling Tool (COAST). The aim of COAST is to support human planners in the specification and scheduling of tasks in a Course of Action. CPNs have been used to develop a formal model of the task execution framework underlying COAST. The CPN model has been extracted in executable form from CPN Tools and embedded directly into COAST, thereby automatically bridging the gap between the formal specification and its implementation. The scheduling capabilities of COAST are based on state space exploration of the embedded CPN model. Planners interact with COAST using a domain-specific graphical user interface (GUI) that hides the embedded CPN model and analysis algorithms. This means that COAST is based on a rigorous semantical model, but the use of formal methods is transparent to the users. Trials of operational planning using COAST have been conducted within the Australian Defence Force. The work of Lin Zhang was done while he was with the Command and Control Division of the Australian Defence Science and Technology Organisation.     

Acute microwave irradiation and cataract formation in rabbits and monkeys.

Rabbits and monkeys were irradiated in the near field of a cavity-backed 2450 MHz resonant slot radiator, to determine the cataractogenic threshold. Rabbits developed cataracts at incident "apparent" power densities of 180 mW/cm2 (E2/120 pi, where E=rms/electric field strength). Monkeys sustained facial burns, but no lens damage, even at incident "apparent" power densities of 500 mW/cm2. These results were substantiated by computer thermal models.     

Risk factors contributing to microbiological contamination of shallow groundwater in Kampala,Uganda

A study of water quality variation in shallow protected springs in Kampala was undertaken over a 12-month period to assess the causes of microbiological contamination. The microbiological quality of water was assessed using thermotolerant coliforms and faecal streptococci. Sanitary inspections and hazard assessments were undertaken to identify faecal sources (hazards), contaminant pathways and contributory factors. Data were collected on rainfall and population as additional factors potentially exerting an influence on microbiological quality. Initial analysis of the data showed a significant relationship between median level of contamination and rainfall, in particular to short-term rainfall events. Total sanitary risk score showed a significant relationship with median level of contamination, but population density may be a confounding factor. The raw microbiological data were transformed into five water quality targets: <1 and < or =10 cfu 100ml(-1) for faecal streptococci; and <1, < or =10 and < or=50 cfu 100 ml(-1) for thermotolerant coliforms. The presence of individual risk factors as well as variables for rainfall and population density were analysed with respect to failure to meet these water quality targets using contingency tables. Logistic regression models were developed for each of the five water quality targets. The analysis strongly suggested that there is rapid recharge of the springs after rainfall and this leads to microbiological contamination. On-site sanitation was less important than other sources of faecal matter, which was consistent with a low sanitation coverage in the study area. The study suggested that improving sanitary completion and local environmental hygiene was more important than controlling on-site sanitation in improving the quality of these springs.     

Book reviews

Urban Planning in Europe: International Competition, National Systems and Planning Projects. Peter Newman & Andy Thornley. London, Routledge 1996, 304pp., £13.99 pb, ISBN 0–415–11179‐X

Regional Development Strategies: A European Perspective. Jeremy Alden & Philip Boland (Eds.). London, RSA/Jessica Kingsley, 1996, 324 pp., £17.95 pb, ISBN 1–85302–356–6

Retailing, Consumption and Capital: Towards the New Retail Geography. Neil Wrigley & Michelle Lowe (Eds). Harlow, Longman, 1996, 352 pp., £17.99 pb, ISBN 0–582–22824–7

The Dependent City Revisited: The Political Economy of Urban Development and Social Policy. Paul Kantor. Westview Press, 1995, 265 pp.

Urban Land and Property Markets in France. Acosta Rodrigo & Renard Vincent. London, UCL Press, 1993, 166 pp., £45.00 hb, ISBN 1–85728–050–4

Experts and Environmental Planning. Bob Evans. Avebury, Aldershot, 1995, 154pp., £32.50, ISBN 1–85628–673–8

The Industrial Enterprise and its Environmental Spatial Perspectives. S. Conti, E.J. Malecki & P. Oinas (Eds). Aldershot, Avebury, 1995, £35.00, ISBN 1–85628–876–5

Negotiating Development: Rationales and Practice for Development Obligations and Planning Gain. Patsy Healey, Michael Purdue & Frank Ennis. London, E & FN Span, 1995, xxi + 278 pages £29.95hb, ISBN 0–419–19410‐X