986 resultados para Road construction contracts.
Resumo:
We detail the automatic construction of R matrices corresponding to (the tensor products of) the (O-m\alpha(n)) families of highest-weight representations of the quantum superalgebras Uq[gl(m\n)]. These representations are irreducible, contain a free complex parameter a, and are 2(mn)-dimensional. Our R matrices are actually (sparse) rank 4 tensors, containing a total of 2(4mn) components, each of which is in general an algebraic expression in the two complex variables q and a. Although the constructions are straightforward, we describe them in full here, to fill a perceived gap in the literature. As the algorithms are generally impracticable for manual calculation, we have implemented the entire process in MATHEMATICA; illustrating our results with U-q [gl(3\1)]. (C) 2002 Published by Elsevier Science B.V.
Resumo:
Work-related falls continues to be one of the leading causes of fatalities in the Australian construction industry, and the failure to use fall protection equipment, such as fall-arrest harnesses and arresting devices, has been found to be a contributing factor. In an attempt to gain an understanding of the issues surrounding the use of fallarrest harness systems by construction workers a study involving semi-structured interviews of 15 male construction workers was carried out at three construction sites. The majority of interviewees commented that there was discomfort in wearing a fall-arrest harness; that there were a number of problems when anchored via an arresting device; and that using a fall-arrest system reduced productivity. Most of the interviewees considered that they needed safety precautions against falls, and they expressed the view that workers’ attitudes towards safety depended critically upon their supervisors’ attitude towards safety. It was also found that workers were not trained in rescue procedures. Interviewees expressed concern that retrieval of a suspended worker may not be carried out in time to prevent the onset of suspension trauma. A number of issues were identified which require further research, such as, investigation into suspension trauma, harness and arresting device design, training provided to workers, and the provision for rescues.
Resumo:
In this paper we present a technique for visualising hierarchical and symmetric, multimodal fitness functions that have been investigated in the evolutionary computation literature. The focus of this technique is on landscapes in moderate-dimensional, binary spaces (i.e., fitness functions defined over {0, 1}(n), for n less than or equal to 16). The visualisation approach involves an unfolding of the hyperspace into a two-dimensional graph, whose layout represents the topology of the space using a recursive relationship, and whose shading defines the shape of the cost surface defined on the space. Using this technique we present case-study explorations of three fitness functions: royal road, hierarchical-if-and-only-if (H-IFF), and hierarchically decomposable functions (HDF). The visualisation approach provides an insight into the properties of these functions, particularly with respect to the size and shape of the basins of attraction around each of the local optima.
Resumo:
The construction sector has one of the worst occupational safety and health records in Europe. The costs of this scenario are very high, namely costs for workers and their families, costs to organizations, resulting from the absence of workers due to illness, insurance premiums, costs resulting from reduced productivity, cost of replacement and training of workers, etc., and costs to society, which in turn increases the costs of health systems. This paper presents and discusses the development of a methodology for economic evaluation in the context of risk management, which will allow senior management to support decision making. The possible application of this methodology to the construction sector is discussed.
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The goal of the present study is mapping the nature of possible contributions of participatory online platforms in citizen actions that may contribute in the fight against cancer and its associated consequences. The research is based on the analysis of online solidarity networks, namely the ones residing on Facebook and the blogosphere, that citizens have been gradually resorting to. The research is also based on the development of newer and more efficient solutions that provide the individual (directly or indirectly affected by issues of oncology) with the means to overcome feelings of impotence and fatality. In this chapter, the authors summarize the processes of usage of these decentralized, freer participatory platforms by citizens and institutions, while attempting to unravel existing hype and stigma; the authors also provide a first survey of the importance and the role of institutions in this kind of endeavor; lastly, they present a prototype, developed in the context of the present study that is specifically dedicated to addressing oncology through social media.
Resumo:
At the close of the Wars of the Roses, a new dynasty was founded by a man lacking a prince’s education; moreover, his weak claim to the throne of England gave rise to a set of serious problems. These two crucial, interrelated elements are central in Francis Bacon’s biographical account of Henry VII. The literal road leading Richmond from exile to victory in Bosworth Field, in 1485, is eventually transformed into a metaphoric path that prefigures the long, deep process of learning undertaken during his 24-year reign. This fundamental process carried out by the king will be approached mainly through the passages focused on the Lambert Simnell/Perkin Warbeck affairs, the most difficult probelms the monarch had to face in a time and in a kingdom of many uncertainties. The Simnell/Warbeck menaces embodied Henry Tudor’s greatest dilemmas, continually emphasised in Bacon’s work – the essence of legitimacy and the essence of royalty.
Resumo:
Low noise surfaces have been increasingly considered as a viable and cost-effective alternative to acoustical barriers. However, road planners and administrators frequently lack information on the correlation between the type of road surface and the resulting noise emission profile. To address this problem, a method to identify and classify different types of road pavements was developed, whereby near field road noise is analyzed using statistical learning methods. The vehicle rolling sound signal near the tires and close to the road surface was acquired by two microphones in a special arrangement which implements the Close-Proximity method. A set of features, characterizing the properties of the road pavement, was extracted from the corresponding sound profiles. A feature selection method was used to automatically select those that are most relevant in predicting the type of pavement, while reducing the computational cost. A set of different types of road pavement segments were tested and the performance of the classifier was evaluated. Results of pavement classification performed during a road journey are presented on a map, together with geographical data. This procedure leads to a considerable improvement in the quality of road pavement noise data, thereby increasing the accuracy of road traffic noise prediction models.
Resumo:
The majority of worldwide structures use concrete as its main material. This happens because concrete is economically feasible, due to its undemanding production technology and case Of use. However, it is widely recognized that concrete production has a strong environmental impact in the planet. Natural aggregates use is one of the most important problems of concrete production nowadays, since they are obtained from limited, and in some countries scarce, resources. In Portugal, although there are enough stone quarries to cover coarse aggregates needs for several more years, Supplies of fine aggregates are becoming scarcer, especially in the northern part of the country. On the other hand, as concrete structures' life cycle comes to an end, an urgent need emerges to establish technically and economically viable solutions for demolition debris, other than for use as road base and quarry fill. This paper presents a partial life cycle assessment (LCA) of concrete made with fine recycled concrete aggregates performed with EcoConcrete tool. EcoConcrete is a tailor-made, interactive, learning and communications tool promoted by the Joint Project Group (JPG) on the LCA of concrete, to qualify and quantify the overall environment impact of concrete products. It consists of an interactive Excel-spreadsheet in which several environmental inputs (material quantities, distances from origin to production Site, production processes) and outputs (material, energy, emissions to air, water, soil or waste) are collected in a life cycle inventory, and are then processed to determine the environmental impact (assessment) of the analysed concrete, in terms of ozone layer depletion, smog or "greenhouse" effect.