961 resultados para Zero reference level


Relevância:

30.00% 30.00%

Publicador:

Resumo:

In October 2008 UK government announced very ambitious commitment to reduce greenhouse gas emissions of at least 34% by 2020 and by 80% by 2050 against a 1990 baseline. Consequently the government declares that new homes should be built to high environmental standards which means that from 2016 new homes will have to be built to a Zero Carbon standard. The paper sets out to present UK zero carbon residential development achieving the highest, Level 6 of Code for Sustainable Homes standard. Comprehensive information is provided about various environmental aspects of the housing development. Special attention is given to energy efficiency features of the houses and low carbon district heating solution which include biomass boiler, heat pumps, solar collectors and photovoltaic panels. The paper presents also challenges which designers and builders had to face delivering houses of the future.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Internal gravity waves generated in two-layer stratified shear flows over mountains are investigated here using linear theory and numerical simulations. The impact on the gravity wave drag of wind profiles with constant unidirectional or directional shear up to a certain height and zero shear above, with and without critical levels, is evaluated. This kind of wind profile, which is more realistic than the constant shear extending indefinitely assumed in many analytical studies, leads to important modifications in the drag behavior due to wave reflection at the shear discontinuity and wave filtering by critical levels. In inviscid, nonrotating, and hydrostatic conditions, linear theory predicts that the drag behaves asymmetrically for backward and forward shear flows. These differences primarily depend on the fraction of wavenumbers that pass through their critical level before they are reflected by the shear discontinuity. If this fraction is large, the drag variation is not too different from that predicted for an unbounded shear layer, while if it is small the differences are marked, with the drag being enhanced by a considerable factor at low Richardson numbers (Ri). The drag may be further enhanced by nonlinear processes, but its qualitative variation for relatively low Ri is essentially unchanged. However, nonlinear processes seem to interact constructively with shear, so that the drag for a noninfinite but relatively high Ri is considerably larger than the drag without any shear at all.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

The Portable Antiquities Scheme (PAS) database includes records of over 225,000 artefacts of Roman date, with a wide geographical coverage and the potential to contribute to our understanding of Romano-British landscapes and settlement at several scales of analysis. This paper draws upon the author’s doctoral research to describe regional case studies from six counties (Wiltshire, Worcestershire, Warwickshire, Northamptonshire, North Lincolnshire and Cumbria) on the use of PAS data. The data have value nationally and regionally as general guides to ancient settlement patterns, but it is arguably at the micro-scale that they have the most potential. With reference to detailed landscape studies from parts of Warwickshire and Wiltshire, the paper argues that sites represented by PAS data are often rural settlements that show evidence for continued activity throughout the Roman period. The paper demonstrates that with an appropriate methodology PAS data can be an immensely valuable archaeological resource, particularly when interpreted at multiple scales, and can be considerably more than a guide to broad distributions of Roman finds.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

During the last century, global climate has been warming, and projections indicate that such a warming is likely to continue over coming decades. Most of the extra heat is stored in the ocean, resulting in thermal expansion of seawater and global mean sea level rise. Previous studies have shown that after CO2 emissions cease or CO2 concentration is stabilized, global mean surface air temperature stabilizes or decreases slowly, but sea level continues to rise. Using idealized CO2 scenario simulations with a hierarchy of models including an AOGCM and a step-response model, the authors show how the evolution of thermal expansion can be interpreted in terms of the climate energy balance and the vertical profile of ocean warming. Whereas surface temperature depends on cumulative CO2 emissions, sea level rise due to thermal expansion depends on the time profile of emissions. Sea level rise is smaller for later emissions, implying that targets to limit sea level rise would need to refer to the rate of emissions, not only to the time integral. Thermal expansion is in principle reversible, but to halt or reverse it quickly requires the radiative forcing to be reduced substantially, which is possible on centennial time scales only by geoengineering. If it could be done, the results indicate that heat would leave the ocean more readily than it entered, but even if thermal expansion were returned to zero, the geographical pattern of sea level would be altered. Therefore, despite any aggressive CO2 mitigation, regional sea level change is inevitable.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

This research has responded to the need for diagnostic reference tools explicitly linking the influence of environmental uncertainty and performance within the supply chain. Uncertainty is a key factor influencing performance and an important measure of the operating environment. We develop and demonstrate a novel reference methodology based on data envelopment analysis (DEA) for examining the performance of value streams within the supply chain with specific reference to the level of environmental uncertainty they face. In this paper, using real industrial data, 20 product supply value streams within the European automotive industry sector are evaluated. Two are found to be efficient. The peer reference groups for the underperforming value streams are identified and numerical improvement targets are derived. The paper demonstrates how DEA can be used to guide supply chain improvement efforts through role-model identification and target setting, in a way that recognises the multiple dimensions/outcomes of the supply chain process and the influence of its environmental conditions. We have facilitated the contextualisation of environmental uncertainty and its incorporation into a specific diagnostic reference tool.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Mixing layer height (MLH) is one of the key parameters in describing lower tropospheric dynamics and capturing its diurnal variability is crucial, especially for interpreting surface observations. In this paper we introduce a method for identifying MLH below the minimum range of a scanning Doppler lidar when operated at vertical. The method we propose is based on velocity variance in low-elevation-angle conical scanning and is applied to measurements in two very different coastal environments: Limassol, Cyprus, during summer and Loviisa, Finland, during winter. At both locations, the new method agrees well with MLH derived from turbulent kinetic energy dissipation rate profiles obtained from vertically pointing measurements. The low-level scanning routine frequently indicated non-zero MLH less than 100 m above the surface. Such low MLHs were more common in wintertime Loviisa on the Baltic Sea coast than during summertime in Mediterranean Limassol.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

The United Kingdom is committed to a raft of requirements to create a low-carbon economy. Buildings consume approximately 40% of UK energy demand. Any improvement on the energy performance of buildings therefore can significantly contribute to the delivery of a low-carbon economy. The challenge for the construction sector and its clients is how to meet the policy requirements to deliver low and zero carbon (LZC) buildings, which spans broader than the individual building level, to requirements at the local and regional levels, and wider sustainability pressures. Further, the construction sector is reporting skills shortages coupled with the need for ‘new skills’ for the delivery of LZC buildings. The aim of this paper is to identify, and better understand, the skills required by the construction sector and its clients for the delivery of LZC buildings within a region. The theoretical framing for this research is regional innovation system (RIS) using a socio-technical network analysis (STNA) methodology. A case study of a local authority region is presented. Data is drawn from a review of relevant local authority documentation, observations and semi-structured interviews from one (project 1) of five school retrofit projects within the region. The initial findings highlight the complexity surrounding the form and operation of the LZC network for project 1. The skills required by the construction sector and its clients are connected to different actor roles surrounding the delivery of the project. The key actors involved and their required skills are: project management and energy management skills required by local authority; project management skills (in particular project planning), communication and research skills required by school end-users; and a ‘technical skill’ relating to knowledge of a particular energy efficient measure (EEM) and use of equipment to implement the EEM is required by the EEM contractors.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Preventing the development of obesity in children is an international health priority. To assess the effectiveness of interventions designed to prevent obesity, promote healthy eating and/or physical activity and/or to reduce sedentary behaviours in 0–5-year-old children, a systematic review of the literature was performed. Literature searches were limited to articles published between January 1995 and June 2006, printed in English and sampling children aged 0–5-years. Searches excluded literature concerned with breastfeeding, eating disorders, and interventions which were school-based or concerned with obesity treatment. Two reviewers independently extracted data and assessed study strengths and weaknesses. Nine included studies were grouped based on the settings in which they were delivered. Most studies involved multi-approach interventions, were conducted in the USA and varied in study designs and quality. All showed some level of effectiveness on at least one obesity-behaviour in young children. These studies support, at a range of levels, the premise that parents are receptive to and capable of some behavioural changes that may promote healthy weight in their young children. The small quantity of research heralds the need, particularly given the potential for early intervention to have long-lasting impacts on individual and population health, to build in a substantial way upon this evidence base.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Australians, in the main, are unaware of the role which Australia played in the evangelization of China in the late nineteenth and the first half of the twentieth century. Most would never have heard of the China Inland Mission (CIM), the largest of the Protestant bodies which penetrated the Middle Kingdom, and few would know of the contribution that its Australian contingent, which consistently comprised about a tenth of the CIM's numbers, made towards the Christianization of that vast country. This thesis aims to raise the level of awareness in this area. Academic researchers have not totally neglected to examine the proselytization of China, and historians of the stature of Latourette have not let it escape their attention. However, most of the studies which have not merely fleetingly focused on the subject while viewing a larger canvas, have been North American, singling out the efforts of United States and Canadian bodies in introducing Christianity to the Chinese. Here, authors like Amerding, Bacon, Creighton, Gates, Hawkes, Ho, Ko, Mensendiek, Michell and Quale have left their mark. In the case of the present thesis, the outlook from which events played out in China are viewed is firmly based in Australia rather than North America. Earlier Australian research has been scarce, and is dominated by Loane and Dixon. Loane, evidently primarily working from Australasian Council minutes, mainly concentrates on the efforts of the CIM's Home Council, examining its endeavours decade by decade against a backdrop of contemporaneous events in China, and briefly referring to aspects of the lives of a cross-section of Australasian missionaries, without providing much idea about what they actually did in the field or what they achieved there. Because of its preoccupation with the Home Council, which never admitted women into its ranks, Loane's treatise is systemically biased towards men, though the more prominent of the women, like Mary Reed and Susie Garland, are given due recognition. The current thesis looks in detail at what Australians did in the field, the level of success they achieved, and at the particular contribution of Australian women towards the evangelization of China. Dixon took upon herself the formidable task of examining the endeavours of all missions in China which contained Australian missionaries. Because of the magnitude of her task, she could not focus to any great extent on particular missions, nor pursue in any detail the work of individual Australian missionaries. Like Loane, she was unable to explore what they actually did in the field or what they achieved there. Neither could she delve to any depth into the work of Australian women missionaries, though on the basis of the information she had accumulated, she drew the conclusion that Australian women had largely only brought about some unintended feminist consequences amongst Chinese women. This sweeping generalization failed to take into account the other very real social changes for Chinese women the Australian female missionaries quite purposely helped to bring about, and this thesis makes good that omission. This thesis studies aspects of the Australian missionary endeavour which both Loane and Dixon have neglected, thereby breaking new ground, and sets out to correct erroneous impressions which Dixon's dissertation has left on the historical record. One of these impressions concerned the longevity of the effect of the Australian effort in China. She had the View, writing in 1978, that the Chinese Church was moribund (a view shared by Varg and Lacy) , and that therefore the effects attributable to the endeavours of any nationality had proved fruitless, whereas the author is able to show, using modern-day sources, that the church has burgeoned in recent years thanks to earlier missionary endeavours and later neo-evangelistic efforts like Gospel radio, and now has a complement of perhaps 50 million adherents, making it second only to the United States in the size of its Protestant evangelical population. Another impression she left was that the Australian input into the evangelization of China can be largely dismissed because no totally Australian organization emerged, leaving the direction of Australia's effort in other hands. Contrary to that impression, the author shows that the Australian impact in China was significant and that Australians enjoyed more power than Dixon ever imagined. The author also shows that Australians were accepted as the equal of other nationalities in the CIM once they had acquired the necessary field expertise, a factor which doubtless also applied in respect of other missions with Australian components in China. Marchant has suggested that it is a fiction perpetuated by mission periodicals that Christianity spread and progressed in a determined manner in China. This thesis establishes that within the CIM's bailiwick, though there was some patchiness, Christianity progressed steadily and inexorably. One mission alone, the CIM, is concentrated upon, firstly in order to render the data manageable, secondly because it was the largest mission in China and had a sizeable Australian (including female) contingent, and thirdly because it exemplified many of the problems which would have been faced by missions in that country and their Australian components. The methodology employed is multifaceted. The written testimony of the missionaries themselves, contained in CIM periodicals, Field Bulletins, Monthly Notes, Annual Reports, autobiographies, personal files, diaries and letters is used to illustrate various aspects of the CIM's work in which Australians were engaged. This approach is augmented by other sources such as China and Australasian Home Council Minutes, missionary conference reports, Candidates' Books, biographies, and other selected material from archival holdings in Australia, Singapore, the United Kingdom, America and Canada. Statistics, especially ratio analyses and growth rate comparisons are used to demonstrate the relative success of different missions, missionaries and genders. Also employed are reminiscences of missionaries and descendants obtained by personal interview, and these are aggregated to provide some general conclusions. Data from these various sources have been synthesized to serve the central objective of demonstrating the importance of the contribution of Australians to the penetration of China by the CIM in the period 1888-1953 with particular reference to the work of Australian women missionaries.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

A new homologous series of norbornylogous (NB) bridges has been synthesized in which the average curvature of the bridges is very small. The molecules are rigid and have two thiol moieties at each end to allow them to form self-assembled monolayers (SAMs) and to connect to two gold electrodes to form a molecular junction. The SAMs formed were characterized using electrochemistry to determine the surface coverage of molecules on gold surface and to provide an indication of the packing of the NB bridges while ellipsometry and X-ray photoelectron spectroscopy (XPS) were used to provide an indication of the SAM thickness and orientation. Single molecule conductance of NB bridges was measured as a function of the molecular length. The conductance was found to decrease exponentially with the length with a decay constant that is exactly correlated with photoelectron transfer and other studies at the multiple molecule level. The molecule−electrode contact resistance was determined and compared with that of related alkanedithiol molecular junctions.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Zero-day or unknown malware are created using code obfuscation techniques that can modify the parent code to produce offspring copies which have the same functionality but with different signatures. Current techniques reported in literature lack the capability of detecting zero-day malware with the required accuracy and efficiency. In this paper, we have proposed and evaluated a novel method of employing several data mining techniques to detect and classify zero-day malware with high levels of accuracy and efficiency based on the frequency of Windows API calls. This paper describes the methodology employed for the collection of large data sets to train the classifiers, and analyses the performance results of the various data mining algorithms adopted for the study using a fully automated tool developed in this research to conduct the various experimental investigations and evaluation. Through the performance results of these algorithms from our experimental analysis, we are able to evaluate and discuss the advantages of one data mining algorithm over the other for accurately detecting zero-day malware successfully. The data mining framework employed in this research learns through analysing the behavior of existing malicious and benign codes in large datasets. We have employed robust classifiers, namely Naïve Bayes (NB) Algorithm, k−Nearest Neighbor (kNN) Algorithm, Sequential Minimal Optimization (SMO) Algorithm with 4 differents kernels (SMO - Normalized PolyKernel, SMO – PolyKernel, SMO – Puk, and SMO- Radial Basis Function (RBF)), Backpropagation Neural Networks Algorithm, and J48 decision tree and have evaluated their performance. Overall, the automated data mining system implemented for this study has achieved high true positive (TP) rate of more than 98.5%, and low false positive (FP) rate of less than 0.025, which has not been achieved in literature so far. This is much higher than the required commercial acceptance level indicating that our novel technique is a major leap forward in detecting zero-day malware. This paper also offers future directions for researchers in exploring different aspects of obfuscations that are affecting the IT world today.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

It is paramount to provide seamless and ubiquitous access to rich contents available online to interested users via a wide range of devices with varied characteristics. Recently, a service-oriented content adaptation scheme has emerged to address this content-device mismatch problem. In this scheme, content adaptation functions are provided as services by third-party providers. Clients pay for the consumed services and thus demand service quality. As such, negotiating for the QoS offers, assuring negotiated QoS levels and accuracy of adapted content version are essential. Any non-compliance should be handled and reported in real time. These issues elevate the management of service level agreement (SLA) as an important problem. This chapter presents prior work, important challenges, and a framework for managing SLA for service-oriented content adaptation platform.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

The detection and control of the temperature variation at the nano-scale level of thermo-mechanical materials during a compression process have been challenging issues. In this paper, an empirical method is proposed to predict the temperature at the nano-scale level during the solid-state phase transition phenomenon in NiTi shape memory alloys. Isothermal data was used as a reference to determine the temperature change at different loading rates. The temperature of the phase transformed zone underneath the tip increased by _3 to 40 _C as the loading rate increased. The temperature approached a constant with further increase in indentation depth. A few layers of graphene were used to enhance the cooling process at different loading rates. Due to the presence of graphene layers the temperature beneath the tip decreased by a further _3 to 10 _C depending on the loading rate. Compared with highly polished NiTi, deeper indentation depths were also observed during the solidstate phase transition, especially at the rate dependent zones. Larger superelastic deformations confirmed that the latent heat transfer through the deposited graphene layers allowed a larger phase transition volume and, therefore, more stress relaxation and penetration depth.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Objective

This study aimed to identify cultural-level variables that may influence the extent to which adolescents from different cultural groups are dissatisfied with their bodies.

Design.
A sample of 1730 male and 2000 female adolescents from Australia, Fiji, Malaysia, Tonga, Tongans in New Zealand, China, Chile, and Greece completed measures of body satisfaction, and the sociocultural influences on body image and body change questionnaire, and self-reported height and weight. Country gross domestic product and national obesity were recorded using global databases.

Results.
Prevalence of obesity/overweight and cultural endorsement of appearance standards explained variance in individual-level body dissatisfaction (BD) scores, even after controlling for the influence of individual differences in body mass index and internalization of appearance standards.

Conclusions.
Cultural-level variables may account for the development of adolescent BD.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

This study investigates some of the differences and similarities between Kurdish-Persian bilinguals and Persian monolinguals with respect to the use of referring expressions in spoken narratives. The narratives were elicited from 36 participants, consisting of 24 bilinguals (groups 1 and 2) and 12 monolinguals (group 3) in the first four grades of primary school using the Mayer’s (1969) book ‘Frog, where are you?’. The results have revealed that group 1 (bilingual told the story in Kurdish) used definite noun phrases most frequently followed by zero anaphors, indefinite noun phrases and pronouns. Group 2 who narrated the story in Persian produced definite nouns most frequently followed by pronouns, zero anaphors and indefinite noun phrases and group 3 (Persian monolinguals) employed definite noun phrases followed by zero anaphors, pronouns, and indefinite noun phrases. The significant difference between groups 1 and 2 and groups 2 and 3 has been in indefinite noun phrases and between groups 1 and 3 in the use of pronouns. One reason is that children universally apply similar strategies regardless of their first language (Berman, 2001). The conclusion is that some of the differences are due to the difference in the structure between Persian and the dialects of Kurdish.