WMR navigation using local potential field corridors and narrow local occupancy grid perception

Path planning and control strategies applied to autonomous mobile robots should fulfil safety rules as well as achieve final goals. Trajectory planning applications should be fast and flexible to allow real time implementations as well as environment interactions. The methodology presented uses the on robot information as the meaningful data necessary to plan a narrow passage by using a corridor based on attraction potential fields that approaches the mobile robot to the final desired configuration. It employs local and dense occupancy grid perception to avoid collisions. The key goals of this research project are computational simplicity as well as the possibility of integrating this method with other methods reported by the research community. Another important aspect of this work consist in testing the proposed method by using a mobile robot with a perception system composed of a monocular camera and odometers placed on the two wheels of the differential driven motion system. Hence, visual data are used as a local horizon of perception in which trajectories without collisions are computed by satisfying final goal approaches and safety criteria

Single versus multiple occupancy - Effects on toxicity parameters measured on Eisenia fetida in lead nitrate-treated soil

The mortality (7 and 14 d), weight change (7 and 14 d), and metal uptake of Eisenia fetida (Savigny, 1826) kept in Pb(NO3)(2)-treated Kettering loam soil in single- and multiple-occupancy (10 earthworms) test containers were determined. The number of earthworms to dry mass (g) ratio of soil was 1:50 in both sets of test containers. Lead concentrations were in the nominal range of 0 to 10,000 mg Pb/kg soil (mg/kg hereafter). Levels of mortality at a given concentration were statistically identical between the single- and multiple-occupancy tests, except at 1,800 mg/kg, at which significantly (p less than or equal to 0.05) more mortality occurred in the multiple-occupancy tests. Death of individual earthworms in the multiple-occupancy tests did not trigger death of the other earthworms in that soil. The LC50 values (concentration statistically likely to kill 50% of the population) were identical between the multiple- and single-occupancy soils: 2,662 mg/kg (2,598-2,984, 7 d) and 2,589 mg/kg (2,251-3,013, 14 d) for the multiple-occupancy soils and 2,827 mg/kg (2,443-3,168, both 7 and 14 d) for the single-occupancy soils (values in brackets represent the 95% confidence intervals). Data were insufficient to calculate the concentration statistically likely to reduce individual earthworm mass by 50% (EC50), but after 14 d, the decrease in earthworm weight in the 1,800 and 3,000 mg/kg tests was significantly greater in the multiple- than in the single-occupancy soils. At 1,000, 1,800, and 3,000 mg/kg tests, earthworm Pb tissue concentration was significantly (p less than or equal to 0.05) greater in earthworms from the multiple-occupancy soils. The presence of earthworms increased the NH3 content of the soil; earthworm mortality increased NH3 concentrations further but not to toxic levels.

Sustainable refurbishment: quantifying the impact of façade changes in multi-storey, multi-occupancy buildings

Building refurbishment is key to reducing the carbon footprint and improving comfort in the built environment. However, quantifying the real benefit of a facade change, which can bring advantages to owners (value), occupants (comfort) and the society (sustainability), is not a simple task. At a building physics level, the changes in kWh per m2 of heating / cooling load can be readily quantified. However, there are many subtle layers of operation and mainte-nance below these headline figures which determine how sustainable a building is in reality, such as for example quality of life factors. This paper considers the range of approached taken by a fa/e refurbishment consortium to assess refurbishment solutions for multi-storey, multi-occupancy buildings and how to critically evaluate them. Each of the applued tools spans one or more of the three building parameters of people, product and process. 'De-cision making' analytical network process and parametric building analysis tools are described and their potential impact on the building refurbishment process evaluated.

Post occupancy evaluation of a building employing windcatchers for summer ventilation

A combined windcatcher and light pipe (SunCatcher) was installed in the seminar room at the University of Reading, UK. Monitoring of indoor environment in real weather conditions was conducted to evaluate the application of windcatchers for natural ventilation. In addition, a subjective occupancy survey was undertaken. External weather conditions and internal indoor air quality indicators were recorded. The “tracer-gas decay” method using SF6 was used to establish air change rate for various conditions. The results indicated that the ventilation rate achieved through the windcatcher depends on the difference between internal and external air temperatures, and on wind speed and direction, in agreement with other published work in the area. The indoor air quality parameters were found to be within acceptable levels when the windcatcher was in operation. The measured air change rate was between 1.5ac/h and 6.8ac/h. Occupants’ questionnaires showed 75 per cent satisfaction with the internal conditions and welcomed the installation of the systems in UK buildings.

Evaluation of probabilistic occupancy map people detection for surveillance systems

In this paper, we evaluate the Probabilistic Occupancy Map (POM) pedestrian detection algorithm on the PETS 2009 benchmark dataset. POM is a multi-camera generative detection method, which estimates ground plane occupancy from multiple background subtraction views. Occupancy probabilities are iteratively estimated by fitting a synthetic model of the background subtraction to the binary foreground motion. Furthermore, we test the integration of this algorithm into a larger framework designed for understanding human activities in real environments. We demonstrate accurate detection and localization on the PETS dataset, despite suboptimal calibration and foreground motion segmentation input.

Value management and post-occupancy evaluation: closing the loop

This paper considers the relationship between value management and facilities management. The findings are particularly relevant to large client organisations which procure new buildings on a regular basis. It is argued that the maximum effectiveness of value management can only be achieved if it is used in conjunction with an ongoing commitment to post-occupancy evaluation. SMART value management is seen to provide the means of ensuring that an individual building design is in alignment with the client’s strategic property needs. However, it is also necessary to recognise that an organisation’s strategic property needs will continually be in a state of change. Consequentially, economic and functional under-performance can only be avoided by a regular performance audit of existing property stock in accordance with changing requirements. Such a policy will ensure ongoing competitiveness through organisational learning. While post-occupancy evaluation represents an obvious additional service to be provided by value management consultants, it is vital that the necessary additional skills are acquired. Process management skills and social science research techniques are clearly important. However, there is also a need to improve mechanisms for data manipulation. Success can only be achieved if equal attention is given to issues of process, structure and content.