955 resultados para worked-examples


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The requirement for the use of Virtual Engineering, encompassing the construction of Virtual Prototypes using Multidisciplinary Design Optimisation, for the development of future aerospace platforms and systems is discussed. Some of the activities at the Virtual Engineering Centre, a University of Liverpool initiative, are described and a number of case studies involving a range of applications of Virtual Engineering illustrated.

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This paper introduces a logical model of inductive generalization, and specifically of the machine learning task of inductive concept learning (ICL). We argue that some inductive processes, like ICL, can be seen as a form of defeasible reasoning. We define a consequence relation characterizing which hypotheses can be induced from given sets of examples, and study its properties, showing they correspond to a rather well-behaved non-monotonic logic. We will also show that with the addition of a preference relation on inductive theories we can characterize the inductive bias of ICL algorithms. The second part of the paper shows how this logical characterization of inductive generalization can be integrated with another form of non-monotonic reasoning (argumentation), to define a model of multiagent ICL. This integration allows two or more agents to learn, in a consistent way, both from induction and from arguments used in the communication between them. We show that the inductive theories achieved by multiagent induction plus argumentation are sound, i.e. they are precisely the same as the inductive theories built by a single agent with all data. © 2012 Elsevier B.V.

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Weathering rinds have been used for decades as relative age indicators to differentiate glacial deposits in long Quaternary sequences, but only recently has it been shown that rinds contain long and extensive palaeoenvironmental records that often extend far beyond mere repositories of chemical weathering on both Earth and Mars. When compared with associated palaeosols in deposits of the same age, rinds often carry a zonal weathering record that can be correlated with palaeosol horizon characteristics, with respect to both abiotic and biotic parameters. As demonstrated with examples from the French and Italian Alps, rinds in coarse clastic sediment contain weathering zones that correlate closely with horizon development in associated palaeosols of presumed Late Glacial age. In addition to weathering histories in both rinds and palaeosols, considerable evidence exists to indicate that the black mat impact (12.8 ka) reached the European Alps, a connection with the Younger Dryas readvance supported by both mineral and chemical composition. Preliminary metagenomic microbial analysis using density gradient gel electrophoresis suggests that the eubacterial microbial population found in at least one Ah palaeosol horizon associated with a rind impact site is different from that in other Late Glacial and Younger Dryas surface palaeosol horizons. © 2013 The Geological Society of London.

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Background There has been an increasing interest in the health effects of long
working hours, but little empirical evidence to substantiate early
10 case series suggesting an increased mortality risk. The aim of the
current study is to quantify the mortality risk associated with long
working hours and to see if this varies by employment relations and
conditions of occupation.
Methods A census-based longitudinal study of 414 949 people aged 20-59/64
15 years, working at least 35 h/week, subdivided into four occupational
classes (managerial/professional, intermediate, own account workers,
workers in routine occupations) with linkage to deaths records
over the following 8.7 years. Cox proportional hazards models were
used to examine all-cause and cause-specific mortality risk.
20 Results Overall 9.4% of the cohort worked 55 or more h/week, but this
proportion was greater in the senior management and professional
occupations and in those who were self-employed. Analysis of 4447
male and 1143 female deaths showed that hours worked were
associated with an increased risk of all-cause mortality only for
25 men working for more than 55 or more h/week in routine/semiroutine
occupations [adjusted hazard ratios (adjHR) 1.31: 95%
confidence intervals (CIs) 1.11, 1.55)] compared with their peers
working 35–40 h/week. Their equivalent risk of death from cardiovascular
disease was (adjHR 1.49: 95% CIs 1.10, 2.00).
30 Conclusions These findings substantiate and add to the earlier studies indicating
the deleterious impact of long working hours but also suggest that
the effects are moderated by employment relations or conditions of
occupation. The policy implications of these findings are discussed.

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Public policy is expected to be both responsive to societal views and accountable to all citizens. As such, policy is informed, but not governed, by public opinion. Therefore, understanding the attitudes of the public is important, both to help shape and to evaluate policy priorities. In this way, surveys play a potentially important role in the policy making process.

The aim of this paper is to explore the role of survey research in policy making in Northern Ireland, with particular reference to community relations (better known internationally as good relations). In a region which is emerging from 40 years of conflict, community relations is a key policy area.

For more than 20 years, public attitudes to community relations have been recorded and monitored using two key surveys: the Northern Ireland Social Attitudes Survey (1989 to 1996) and the Northern Ireland Life and Times Survey (1998 to present). This paper will illustrate how these important time series datasets have been used to both inform and evaluate government policy in relation to community relations. By using four examples, we will highlight how these survey data have provided key government indicators of community relations, as well as how they have been used by other groups (such as NGOs) within policy consultation debates. Thus, the paper will provide a worked example of the integral, and bi-directional relationship between attitude measurement and policy making.

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This chapter presents an overview on several performance-based approaches for concrete durability specification and conformity assessment of the as-built structure.

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Evidence for osseous technologies has featured in excavation reports from Southeast Asia for almost a century and from archaeological deposits as old as 43,000 years BP. However, in contrast to the significance that is placed on this technology in other parts of the world, until recently, Southeast Asian assemblages have drawn only very limited attention. Concentrating on evidence from Malaysia, the current paper examines one element of this inventory of tools: the deliberate modification of pig canines and the means by which such alteration can be distinguished from patterns of natural tooth wear. Particular attention is paid to the bearded pig (Sus barbatus), as it is one of the two species of wild boar in Malaysia whose tusks are most likely to have been used by prehistoric toolmakers. Reference is also made to wider, regional ethnographic examples of known tusk implements and their accredited uses to further assist in the identification process. Distinguishing criteria for worked tusk are formulated according to the type and extent of modification. These criteria are then applied to archaeological specimens recovered from two prehistoric cave sites in Malaysia, Gua Bintong and Niah Cave.

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Contemporary architecture has tended to increase envelope insulation levels in an unceasing effort to reduce U-values. Traditional masonry architecture in contrast was devoid of insulation, except for the inherent insulative nature of vernacular materials. Also the consistency of the outer membrane of the building skin diminished any impact due to bridging. In contemporary highly insulated walls bridges are numerous due to the necessity to bind inner and outer structural skins through insulation layers. This paper examines thermal bridging in an example of contemporary façade design and compares it with an example of traditional vernacular architecture currently being researched which is characterized by a lack of bridging elements. Focus is given to heavy weight materials of high thermal mass, which appropriately for passive architecture help moderate fluctuations in internal temperature. In an extensive experimental study samples of highly insulated precast concrete sandwich panels and lime rendered masonry walls are tested in a guarded hot-box. The building construction methods are compared for static and dynamic thermal transmittance, via heat flux and surface temperature differential measurements. Focus is given to the differential heat loss due to the thermal bridging in the sandwich panels and its associated impact on overall heat loss relative to traditional masonry construction.

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Rock rinds have been used for half a century to date glacial deposits and recently inroads have been developed to use nuclides to provide absolute ages of weathering rinds in pebble clasts. Although maximum and minimum rind thicknesses have helped to elucidate time since deposition and allowed stratigraphic division of deposits at glacial rank, little has been done to investigate the wealth of mineral degradation, growth of alteration products and biomineralization that occur in these weathered crusts. In some cases the mass of microbe-mineral intergrowth is nearly present on a 50%/50% basis, with the biotic mass intergrown with mineral matter to such an extent that it probably controls pH and redox phenomena that act as accelerators in the weathering process. Assuming weathering time spans of 2 × 106 years or more for a complete cycle, eventual clast decomposition is the end product. Here we present evidence of microbe-clast intergrowth from selected sites of Pleistocene age (~70 ka to 2.0 Ma) in the lower Afroalpine of Mt. Kenya and hypothesize about its role in rock decomposition and fossilization of biotic end-members. © 2013 Copyright Taylor and Francis Group, LLC.

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Committee: Glennys Young, Dan Abramson, Chris Jones