939 resultados para Life cycle cost analysis


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A major contributory factor to poor project performance in the construction industry is known to be the lack of integration and coordination between the different disciplines involved in various stages of the procurement process. Attempts by researchers to address this problem have met with limited success, as they have focused mainly on adapting integration techniques originally developed for use in the manufacturing industry. There is therefore a need to develop a detailed understanding of the fundamental sciences that underpin the problem of integrating the procurement process across the construction project life cycle. Presents and discusses a research model for addressing major methodological issues in the analysis of design/construction relationships.

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We analyse the wood and concrete designs of the Wälludden building described by Börjesson et al. (Energy Policy 28 (2000) 575) in terms of their embodied energy, employing an environmentally extended input–output framework in a tiered hybrid life-cycle assessment, and in a structural path analysis. We illustrate the complexity of the inter-industry supply chains underlying the upstream energy requirements for the building options, and demonstrate that higher-order inputs are difficult to capture in a conventional process analysis. Our calculations show that Börjesson and Gustavsson's estimates of energy requirements and greenhouse gas emissions are underestimated by a factor of about 2, and that corresponding greenhouse gas balances are positive at about 30 t C-eq. Nevertheless, Börjesson and Gustavsson's general result—the concrete-framed building causing higher emissions—still holds.

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During the period of 1990-2002 US households experienced a dramatic wealth cycle, induced by a 369% appreciation in the value of real per capita liquid stock market assets followed by a 55% decline. However, consumer spending in real terms continued to rise throughout this period. Using data from 1990-2005, traditional life-cycle approaches to estimating macroeconomic wealth effects confront two puzzles: (i) econometric evidence of a stable cointegrating relationship among consumption, income, and wealth is weak at best; and (ii) life-cycle models that rely on aggregate measures of wealth cannot explain why consumption did not collapse when the value of stock market assets declined so dramatically. We address both puzzles by decomposing wealth according to the liquidity of household assets. We find that the significant appreciation in the value of real estate assets that occurred after the peak of the wealth cycle helped sustain consumer spending from 2001 to 2005.

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Clubroot, caused by Plasmodiophora brassicae, is the most devastating soil-borne disease of vegetable brassicas. It occurs all over the world and is responsible for crop losses of up to 10% every year. In Australia, the disease is being managed effectively with chemicals and cultural practices, but ideally control can be improved in the long term by the introduction of resistant cultivars. The life cycle ofP. brassicae and mode of action of plant resistance has not been fully elucidated because of the technical difficulties of working with an obligate, soil-borne plant pathogen. However, Arabidopsis thaliana, which is a host ofP. brassicae, has great potential as a model system for studying the life cycle, the infection process and development of resistance. We have developed a sand-liquid-culture system for growing Arabidopsis that allows easy observation of all life stages and, most importantly, the primary plasmodial stages within the root hair. The method was first optimised for observations of the lifecycle of the pathogen in a susceptible Arabidopsis ecotype (Col-3) where all stages of the lifecycle have now been observed and characterised. Further screening of Arabidopsis ecotypes for disease resistance has utilised one of the most virulent Australian pathotypes of brassica (ECD number 16/19/31). To date, Arabidopsis ecotype Ta-0 has shown a level of tolerance to the disease even though the roots get infected. It has been reported earlier that resistance toP. brassicae in Arabidopsis is due to one or a small number of genes. To examine changes in gene expression during the early, critical stages of infection, RNA was extracted from the susceptible and resistant ecotypes at two time points, 4 days and 17 days after inoculation. Microarray analysis will be used to investigate genome wide changes in gene expression during infection but also to identify candidate genes that may confer resistance to Australian isolates of the pathogen.

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We study the optimal size of a pay-as-you-go social security program for an economy composed of both permanent-income and hand-to-mouth consumers. While previous work on this topic is framed within a two-period partial equilibrium setup, we study this issue in a life-cycle general equilibrium model. Because this type of welfare analysis depends critically on unobservable preference parameters, we methodically consider all parameterizations of the unobservables that are both feasible and reasonable—all parameterizations that can mimic key features of macro data (feasible) while still being consistent with micro evidence and convention (reasonable). The baseline model predicts that the optimal tax rate is between 6 percent and 15 percent of wage income.

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To help avoid conflict and even market rejection, the design and introduction of new technologies can be aided by consideration of the potential concerns of different stakeholder groups. An assessment of their desired goals for technological change may be useful for pre-empting changes in the  parameters of acceptability for technologies. As part of a research  programme evaluating the parameters of acceptability for bio-based  technologies using life cycle assessment of products and an analysis of the  perceptual frameworks of stakeholders, respondents from four stakeholder  groups in New Zealand were interviewed about the desirable and  undesirable trajectories for chemical modification technologies. Three  examples of pine decking products derived using different amounts and  types of chemical modification served to help explore the contemporary  criteria and rationale for acceptability. The responses of the 70 respondents  in those four groups indicated that new technologies need to be able to  prove their worth with regard to both tangible and intangible qualities if they  are to be accepted into the market in the place of either the existing product  or an inorganic competitor.

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Aim: Costs associated with mental health treatment for young persons at 'ultra' high risk (UHR) of developing a psychotic disorder have not previously been reported. This paper reports cost implications of providing psychological and pharmacological intervention for individuals at UHR for psychosis compared with minimal psychological treatment.

Method: Mental health service costs associated with a randomized controlled trial of two treatments (Specific Preventive Intervention: SPI and Needs-Based Intervention: NBI) for UHR young persons were estimated and compared at three time points: treatment phase, short-term follow up and medium-term follow up.

Results: Although the SPI group incurred significantly higher treatment costs than the NBI group over the treatment phase, they incurred significantly lower outpatient treatment costs over the longer term.

Conclusion: This study indicates that specific interventions designed to treat young persons who are identified as being at UHR of psychosis might be associated with some cost savings compared with non-specific interventions.

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Front-of-pack ‘traffic-light’ nutrition labelling has been widely proposed as a tool to improve public health nutrition. This study examined changes to consumer food purchases after the introduction of traffic-light labels with the aim of assessing the impact of the labels on the ‘healthiness’ of foods purchased. The study examined sales data from a major UK retailer in 2007. We analysed products in two categories (‘ready meals’ and sandwiches), investigating the percentage change in sales 4 weeks before and after traffic-light labels were introduced, and taking into account seasonality, product promotions and product life-cycle. We investigated whether changes in sales were related to the healthiness of products. All products that were not new and not on promotion immediately before or after the introduction of traffic-light labels were selected for the analysis (n = 6 for ready meals and n = 12 for sandwiches). For the selected ready-meals, sales increased (by 2.4% of category sales) in the 4 weeks after the introduction of traffic-light labels, whereas sales of the selected sandwiches did not change significantly. Critically, there was no association between changes in product sales and the healthiness of the products. This short-term study based on a small number of ready meals and sandwiches found that the introduction of a system of four traffic-light labels had no discernable effect on the relative healthiness of consumer purchases. Further research on the influence of nutrition signposting will be needed before this labelling format can be considered a promising public health intervention.

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Recent studies have shown the important roles that new high growth firms can play in job creation and economic development. This paper reviews the positioning of present Australian government policies and programs that intend to be supportive of the development of more high growth businesses; that is those that employ greater than twenty persons. The research explores the environments of a group of new high growth Australian firms and the roles that the various identified government support initiatives have played in their development. The paper also draws on recent research on survival and growth patterns of spin-off companies generated by publicly funded research agencies to map the government support initiatives with the different stages of the high growth business life cycle. The paper reviews issues in the Australian business environment that may have affected the rate of generation of new high growth firms. Of particular relevance has been the progressive freeing up of the Australian labour market and a greater resource allocation to research commercialisation by publicly funded research providers. The analysis has finally separately considered how to produce and support more founders of such high growth firms, their future chief executive officers, the specialist consultants and other professional support people and issues related to access to finance that such firms will need. The research findings draw attention to the important role of government financial support for industry research, particularly at the point where the first product is in the market and resources are scarce. At this point support is vital both to increase the market penetration of the core product and for R&D for product customisation and increasing the product range.

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Anti-malware software producers are continually challenged to identify and counter new malware as it is released into the wild. A dramatic increase in malware production in recent years has rendered the conventional method of manually determining a signature for each new malware sample untenable. This paper presents a scalable, automated approach for detecting and classifying malware by using pattern recognition algorithms and statistical methods at various stages of the malware analysis life cycle. Our framework combines the static features of function length and printable string information extracted from malware samples into a single test which gives classification results better than those achieved by using either feature individually. In our testing we input feature information from close to 1400 unpacked malware samples to a number of different classification algorithms. Using k-fold cross validation on the malware, which includes Trojans and viruses, along with 151 clean files, we achieve an overall classification accuracy of over 98%.

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Australia has joined many governments to adopt public-private partnership (PPP) as a major strategy for procuring infrastructure for decades. However, failures have occurred although the market has been considered to be a mature and sophisticated one. Failures have typically been traced back to inappropriate economic evaluation and a lack of value-for-money. In particular, a literature review has identified that there was no holistic consideration on the evaluation of procurement transactions of PPP projects. The transaction costs of PPPs were not handled properly. In this paper, theories of transaction cost economics are proposed for the purpose of such a holistic institutional economic evaluation. These theories are analysed in order to identify potential critical success factors for a strategic infrastructure procurement framework. The potential critical success factors are identified and grouped into a number of categories that match the theories of transaction cost economics. These categories include (1) Asset Specificity, (2) Organizational Capability, (3) Transaction Frequency, (4) Behavioural Uncertainty, and (5) Environmental Uncertainty. These potential critical success factors may be subject to an empirical test in the future. The proposed framework will offer decision makers with an insight into project life cycle economic outcomes needed to successfully deliver PPPs.

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Existing business models require RFID tag to transfer its ownership during its life cycle. As a result, a RFID tags might have many owners during its life cycle. However, the transfer of ownership should ensure that previous owners have no information about current owner's data. Physical ownership does not ensure digital ownership transfer given the wireless nature of communication with RFID tags. Most of the proposed protocol in this nature is implacable to address aU existing RFID tag ownership transfer scenarios. Moreover, they have many security concerns and vulnerabilities. In this paper, we have investigated and discussed all existing business cases and their transfer scenarios. To cover all ownership transfer scenarios, we have presented an ownership transfer protocol. The proposed protocol has used modified DiffieHellman algorithm to perform ownership request validation and authentication of involved parties. Performance comparison shows that our protocol is practical to implement passive low-cost RFID tags, securely performs tag ownership transfer and can be used for all existing ownership transfer scenarios.