建筑工人个体安全能力影响因素效用量化研究

为加强对工人不安全行为的管理,保障建筑施工安全,利用结构方程模型(SEM)建模方法研究建筑工人个体安全能力与影响因素间的效用关系。从个体特质和工作环境2方面进行分析,得到技能素质、心理状态、生理状态等16个影响因素。以工作环境的8个影响因素作为外源潜伏变量,其余8个影响因素作为内生潜伏变量,构建建筑工人个体安全能力SEM。利用问卷调查所得数据对模型进行拟合与修正,实现影响因素效用的客观量化。研究结果表明:建筑工人的个体安全能力主要取决于其技能素质;工作环境中,效用最大的因素是施工现场的安全资源配备;当前建筑行业的安全培训与安全文化建设工作还有待进一步开展。     

Towards a better management of complex emergencies through crisis management meta‐modelling

Managing complex emergency situations is a challenging task, mainly due to the heterogeneity of the partners involved and the critical nature of such events. Whatever approach is adopted to support this objective, one unavoidable issue is knowledge management. In the context of our research project, gathering, formalising and exploiting all the knowledge and information about a given crisis situation is a critical requirement. This paper presents some research results concerning this specific topic: from a theoretical point of view, the generic dimensions of crisis characterisation are defined, while from a technical point of view, we describe a software solution able to collect that knowledge (based on meta‐models and ontologies). This is used to confront the characteristics of the situation (context) with characteristics of the resources (relief system) in order to design a suitable response. Finally, an illustrative example concerning a crash between a tanker truck and a train is described.     

Future distribution modelling: A stitch in time is not enough

The last two decades have seen an increasing number of studies assessing the impact of climate change upon biodiversity. A central assumption underpinning research into the potential future habitat of terrestrial biota is that species are presently in equilibrium with their environments and that quantitative climate models adequately represent the distribution of species. Recently, many alarming predictions have emerged concerning the extinction and redistribution of species. Here, we show that even large-scale models of the climatic niche dimensions of species are temporally variable. Distributional models were developed for Salix (willow) species occurring in the province of Ontario, Canada, using three historical climate data sets. Although historical data very accurately represented the distributions of willows, the inherent variability within the models of species based on different periods greatly influenced the direction and magnitude of projected distributional change. We expose a fundamental uncertainty with respect to predicting the responses of species to climate change.     

Trade-off between road avoidance and attraction by roadside salt pools in moose: An agent-based model to assess measures for reducing moose-vehicle collisions

Moose-vehicle collisions are a frequent traffic-safety issue, particularly in northern regions where moose are attracted to the near-road areas because they can consume sodium from de-icing salts that accumulate in pools at snowmelt. Moose that find salt pools near roads tend to remember their location and to re-visit them to get the sodium they need in their diet. This study investigated the trade-off between road avoidance and salt pool spatial memory in the movement behaviour of moose using an agent-based model to determine how the interplay of these two factors influences the frequency of road crossings in the Laurentides Wildlife Reserve (Québec, Canada). Mitigation measures studied were the removal of roadside salt pools and the construction of compensatory salt pools away from the road shoulder. A GPS telemetry program of moose in the study area was used to validate our model. The model moose with both road avoidance and salt pool spatial memory activated produced the best results when comparing to the real moose data. Results show that both road avoidance and salt pool spatial memory significantly affect moose road crossings, but that road avoidance explains most of the variance. Road avoidance tended to decrease the number of moose crossings, but this decrease was partly compensated by the spatial memory of salt pools which typically increased the likelihood that moose will cross the road. The trade-off between road avoidance and salt pool memory was largest when original salt pools were maintained. In simulations where road avoidance and salt pool memory were both turned off, the impact of mitigation measures on the number of road crossings was lowest. For the most realistic moose behavior, the management scenarios resulted in reductions in road crossings between 22% and 79%, and the best scenario is to completely remove roadside salt pools. If compensation salt pools are used, they should be located as far as possible from the roads (beyond 500 m) to have an impact on moose road crossings.     

Simulating the potential for ecological restoration of dryland forests in Mexico under different disturbance regimes

Examining the potential for ecological restoration is important in areas where anthropogenic disturbance has degraded forest landscapes. However, the conditions under which restoration of degraded tropical dry forests (TDF) might be achieved in practice have not been determined in detail. In this study, we used LANDIS-II, a spatially explicit model of forest dynamics, to assess the potential for passive restoration of TDF through natural regeneration. The model was applied to two Mexican landscapes under six different disturbance regimes, focusing on the impact of fire and cattle grazing on forest cover, structure and composition. Model results identified two main findings. First, tropical dry forests are more resilient to anthropogenic disturbance than expected. Results suggested that under both a scenario of small, infrequent fires and a scenario of large, frequent fires, forest area can increase relatively rapidly. However, forest structure and composition differed markedly between these scenarios. After 400 years, the landscape becomes increasingly occupied by relatively shade-tolerant species under small, infrequent fires, but only species with both relatively high shade tolerance and high fire tolerance can thrive under conditions with large, frequent fires. Second, we demonstrated that different forms of disturbance can interact in unexpected ways. Our projections revealed that when grazing acts in combination with fire, forest cover, structure and composition vary dramatically depending on the frequency and extent of the fires. Results indicated that grazing and fire have a synergistic effect causing a reduction in forest cover greater than the sum of their individual effects. This suggests that passive landscape-scale restoration of TDF is achievable in both Mexican study areas only if grazing is reduced, and fires are carefully managed to reduce their frequency and intensity.     

Spatio-temporal modelling of ground vegetation development in mountain spruce forests

More complex models of forest ecosystems are required to understand how land-cover changes can impact vegetation dynamics and spatial pattern. In order to document spatio-temporal modelling abilities, the observations conducted in the declined climax mountain Norway spruce forest during the recovery period (1995-2006) are used for simulation and spatial analysis in the GIS environment. The developed spatio-temporal model is used for simulation of forest vegetation dynamics in a mountain spruce forest in the framework of regeneration processes after stress from air pollution. In order to explore the spatial and temporal phenomena of regeneration processes, the spatio-temporal model is based on a large set of ordinary differential equations that solve dynamic processes in sets of microsites arranged in grids for each ground vegetation species and each age group of Norway spruce seedlings. The spatial extent of the explored site is composed of a set of 50 × 50 microsites. Each microsite is represented by a square with dimensions of 1 m × 1 m. The presented simulation studies are mainly focused on seedlings from the seed year 1992, in order to explore the longest monitored time series of survival. It is based on exponential growth models that are related to the environmental conditions for each microsite. The canopy gaps based on estimates of the local crown projected area, the soil type layer, and the dominant grass density are used to provide case simulation studies. The first case study simulates the influence of microsite positions in relation to the local tree crown projections on the survival of spruce seedlings. It is assumed that the density of the trees is the main factor that determines the light and heat supply to the ground level of the Norway spruce seedlings. The second case study extends the previous study to include terms that determine the growth ratio in dependence on the crown projection area. The third case study provides further extensions in order to simulate growth ratio relations to the local soil type. The fourth case study demonstrates the local influence of the dominant grasses, such as Avenella flexuosa and Calamagrostis villosa, on the natural regeneration of Norway spruce. Starting from the conditions at the sites before the recovery period, the case simulation studies are able to project the short-term succession for a regeneration decade and the approximate long-term development. In addition to the standard simulation procedures based on solution of ordinary differential equations, spatio-temporal modelling in the GIS environment is able to provide spatial data management, analysis and visualization of the data.     

Choice of threshold alters projections of species range shifts under climate change

One of the least explored sources of algorithmic uncertainty in bioclimatic envelope models (BEM) is the selection of thresholds to transform modelled probabilities of occurrence (or indices of suitability) into binary predictions of species presence and absence. We investigate the impacts of such thresholds in the specific context of climate change. BEM for European tree species were fitted combining 9 climatic models and emissions scenarios, 7 modelling techniques, and 14 threshold-setting techniques. We quantified sources of uncertainty in projections of turnover, and found that the choice of the modelling technique explained most of the variability (39%), while threshold choice explained 25% of the variability in the results, and their interaction an additional 19%. Choice of future climates explained 9% of total variability among projections. Estimated species range shifts obtained by applying different thresholds and models were grouped by IUCN-based categories of threat. Thresholds had a large impact on the inferred risks of extinction, producing 1.7- to 9.9-fold differences in the proportions of species projected to become threatened by climate change. Results demonstrate that threshold selection has large - albeit often unappreciated - consequences for estimating species range shifts under climate change.     

Eliciting cognitive processes underlying patterns of human-wildlife interactions for agent-based modelling

Integrating humans in our perception of ecosystems is of critical importance to adequately protect natural resources. This poses the challenge of understanding human decision making in the context of decisions potentially threatening nature's integrity. We developed a spatially explicit agent-based model that simulates commercial whale-watching vessel movements based on a representation of the captains’ decision making process when observing marine mammals in and around the Saguenay-St. Lawrence Marine Park in Québec, Canada. We focus here on the human part of the global model, the submodel of whale movements having been developed and validated independently (Lamontagne, 2009). The objective of this study is to select and validate a model of whale-watching captains’ decision making using the pattern-oriented modelling approach (POM): three models of cognitive heuristics (satisficing, tallying and Take The Best) along with a null model (random choice) were tested. These concurrent decision making models were built upon knowledge extracted from data collected during field investigations, including interviews with whale-watching captains and park wardens, onboard and shore-based observations, and analyses of a multi-year dataset of sampled whale-watching excursions. Model selection is performed by statistically comparing simulated and real patterns of boat trajectories (excursion length), spatial hotspots (kernel home range 50%), and excursion content (species observed, time allocated to different activities). The selection process revealed that the Take The Best heuristic was the best performing model. We used the distribution of the number of whale-watching boats in the vicinity (2000 m) of each vessel as a secondary pattern to validate the ability of each decision making model to reproduce real observations. Given the prevalence of the species attribute in the choice of which whale to observe, the Take The Best heuristic's ability to deal with non-compensatory information partly explains its overall best performance. Moreover, implementation of communication abilities between modelled captains led to the emergence of persistent observation sites in the park, which is a well-known collective spatiotemporal characteristic of the whale-watching industry; thus validating the fundamental assumption that cooperation is an important mechanism behind the pattern of whale-watching boat dynamics. The relatively good performance of the satisficing and tallying heuristics supports both field evidence and literature on bounded rationality in that humans likely use collections of heuristics (adaptive toolbox) to solve decision problems in different contexts. The POM strategy appears suitable to build up an informative ABM regarding the management of human activities in a natural environment so that further developments will be assessed following the same approach.     

混凝土板墙加固后墙片与剪力墙性能的对比研究

首先通过3个墙片的水平低周反复伪动力试验,对比研究了混凝土板墙加固后墙片与剪力墙的承载力、耗能能力等各项抗震性能.由于试验条件的限制,试验仅对比研究了120 mm混凝土剪力墙与双面60 mm混凝土板墙加固后墙片的抗震性能.在试验基础上,利用有限元软件建立合理的计算模型,将计算结果与试验结果进行了对比分析;利用该计算模型...     

Mining investment and regional development: A scenario-based assessment for Northern Sweden

The way in which mineral development contributes to economic development in the region where it takes place is important for the mining industry’s relations to the local community. The purpose of this paper is to provide an assessment of the regional-economic impacts of a large-scale contemporary iron ore project in Northern Sweden (including two new mines, two processing plants, and one pellet plant). The regional input-output model rAps, provided by the Swedish government agency NUTEK is used, and it explicitly addresses the linkages between demographic development, the labour market, industrial production and the municipal finances in a consistent modelling framework. The simulation results suggest an average employment multiplier of about 2-2.5 during the maximum production phase, indicating that for every 100 jobs in mining about 100-150 jobs are supported elsewhere in the local economy. The positive impacts in this case are made possible in large because of the existing mining cluster and local suppliers in northern Sweden. Still, these results are perhaps best viewed as an indication of the potential for local economic development as they neglect, for instance, potential supply constraints (e.g., attracting the necessary labour force, road infrastructure, etc.). Specific policies to further strengthen the regional linkage effects may therefore be necessary in order for this potential to be realized in practice, and attention would preferably be paid to policy measures that have positive external spillover effects on the surrounding geographical area.