109 resultados para thomas demand
Resumo:
This paper demonstrates a set of necessary conditions that should generate unbiased, internally consistent estimates of willingness to pay (WTP) from a double referendum mechanism. These conditions are also sufficient for demand revelation in an experimental laboratory environment. However, the control over the mechanism achieved in the lab may not be transferrable to the field and WTP estimates derived from field surveys may remain biased. (c) 2008 Elsevier Inc. All rights reserved.
Resumo:
A queue manager (QM) is a core traffic management (TM) function used to provide per-flow queuing in access andmetro networks; however current designs have limited scalability. An on-demand QM (OD-QM) which is part of a new modular field-programmable gate-array (FPGA)-based TM is presented that dynamically maps active flows to the available physical resources; its scalability is derived from exploiting the observation that there are only a few hundred active flows in a high speed network. Simulations with real traffic show that it is a scalable, cost-effective approach that enhances per-flow queuing performance, thereby allowing per-flow QM without the need for extra external memory at speeds up to 10 Gbps. It utilizes 2.3%–16.3% of a Xilinx XC5VSX50t FPGA and works at 111 MHz.
Resumo:
Recent cold winters and prolonged periods of low wind speeds have prompted concerns about the increasing penetration of wind generation in the Irish and other northern European power systems. On the combined Republic of Ireland and Northern Ireland system there was in excess of 1.5 GW of installed wind power in January 2010. As the penetration of these variable, non-dispatchable generators increases, power systems are becoming more sensitive to weather events on the supply side as well as on the demand side. In the temperate climate of Ireland, sensitivity of supply to weather is mainly due to wind variability while demand sensitivity is driven by space heating or cooling loads. The interplay of these two weather-driven effects is of particular concern if demand spikes driven by low temperatures coincide with periods of low winds. In December 2009 and January 2010 Ireland experienced a prolonged spell of unusually cold conditions. During much of this time, wind generation output was low due to low wind speeds. The impacts of this event are presented as a case study of the effects of weather extremes on power systems with high penetrations of variable renewable generation.
Resumo:
Objectives: To estimate the proportion of cancer outpatients who visit a Complementary and Alternative Medicine (CAM) unit that is located within a conventional cancer treatment centre; to compare the characteristics of CAM unit visitors with those of all outpatients; to monitor the demand for 20 CAM therapies delivered by professionals, and the use of the CAM unit for waiting, gathering information and informal support from volunteer staff.
Design: Prospective, observational, over a six month period.
Setting: CAM unit within a NHS cancer treatment centre.
Main outcome measures: Utilisation of the CAM unit for 20 complementary therapies, and for waiting, gathering information, informal support; characteristics of CAM users compared with those of all cancer outpatients attending the cancer centre; predictors of CAM therapy use and frequent use.
Results: 761 (95% of those approached) people were recruited, 498 (65.4%) cancer patients, 202 (26.5%) relatives, 37 (4.8%) friends/carers, 24 (3.2%) staff. Women predominated (n = 560, 73.6%). Of all outpatients attending the cancer centre, 498 (15.8%) visited the CAM unit, 290 (9.2%) accessed therapies. Compared to all outpatients, those visiting the CAM unit were: younger (mean 63.7 vs. 58.4 years), more likely to be female (57.9% vs. 78.7%), have breast (14.8% vs. 51.9%), gynaecological (5.0% vs. 9.1%) cancer, live in local postal district (57.3% vs. 61.6%). Significant predictors of therapy use and frequent visits were being a patient, female, higher education, living closer to the cancer centre.
Conclusions: Despite easy access to CAM therapies, a relatively small number of people regularly used them, whilst a larger number selectively tried a few. The integrated CAM unit meets a demand for information and informal support. The findings inform emerging policy on integrating CAM and conventional cancer treatment to address psychosocial needs of people with cancer. More research is needed on why people do not use integrated CAM services and how charges affect demand. © 2008.
Resumo:
Dwindling fossil fuel resources and pressures to reduce greenhouse gas (GHG) emissions will result in a more diverse range of generation portfolios for future electricity systems. Irrespective of the portfolio mix the overarching requirement for all electricity suppliers and system operators is that supply instantaneously meets demand and that robust operating standards are maintained to ensure a consistent supply of high quality electricity to end-users. Therefore all electricity market participants will ultimately need to use a variety of tools to balance the power system. Thus the role of demand side management (DSM) with energy storage will be paramount to integrate future diverse generation portfolios. Electric water heating (EWH) has been studied previously, particularly at the domestic level to provide load control, peak shave and to benefit end-users financially with lower bills, particularly in vertically integrated monopolies. In this paper, a continuous Direct Load Control (DLC) EWH algorithm is applied in a liberalized market environment using actual historical electricity system and market data to examine the potential energy savings, cost reductions and electricity system operational improvements.
Resumo:
In this paper we present an empirical analysis of the residential demand for electricity using annual aggregate data at the state level for 48 US states from 1995 to 2007. Earlier literature has examined residential energy consumption at the state level using annual or monthly data, focusing on the variation in price elasticities of demand across states or regions, but has failed to recognize or address two major issues. The first is that, when fitting dynamic panel models, the lagged consumption term in the right-hand side of the demand equation is endogenous. This has resulted in potentially inconsistent estimates of the long-run price elasticity of demand. The second is that energy price is likely mismeasured.
Resumo:
This paper compares the Random Regret Minimization and the Random Utility Maximization models for determining recreational choice. The Random Regret approach is based on the idea that, when choosing, individuals aim to minimize their regret – regret being defined as what one experiences when a non-chosen alternative in a choice set performs better than a chosen one in relation to one or more attributes. The Random Regret paradigm, recently developed in transport economics, presents a tractable, regret-based alternative to the dominant choice paradigm based on Random Utility. Using data from a travel cost study exploring factors that influence kayakers’ site-choice decisions in the Republic of Ireland, we estimate both the traditional Random Utility multinomial logit model (RU-MNL) and the Random Regret multinomial logit model (RR-MNL) to gain more insights into site choice decisions. We further explore whether choices are driven by a utility maximization or a regret minimization paradigm by running a binary logit model to examine the likelihood of the two decision choice paradigms using site visits and respondents characteristics as explanatory variables. In addition to being one of the first studies to apply the RR-MNL to an environmental good, this paper also represents the first application of the RR-MNL to compute the Logsum to test and strengthen conclusions on welfare impacts of potential alternative policy scenarios.
Resumo:
Abstract: A vibrant inner city parish needed space for meetings, language classes, children’s play and other support accommodation as well as a clearer link between the interior of the listed church and the space outside.
The project builds itself about the entrance to the church. The form is manipulated such that the intervention recedes from those entering the church, drawing them into the plan before becoming readable as an addition. The resultant poché between this entrance sequence and the fabric of the church is hollowed out to provide the required accommodation. These rooms are insulated and lined in cork to allow for their use separate to the main body of the church. With budget at a premium the construction methodology was developed from an analysis of traditional Irish boat building techniques, which allowed the use of the solid timber to act as the primary structure with no additional material support.
Constructed in solid walnut the intervention reads with the existing brick interior and yet is clearly identifiable as a contemporary addition.
Aims / Objectives Questions
1 To accommodate new space inside an existing protected structure.
2 To form a new threshold between interior and exterior.
3 To develop an affordable means of construction that would be durable and rapid to erect.
4 To make a contemporary addition in sympathy with the qualities of the existing protect structure, in line with best conservation practice and research.
5 Traditional forms of construction as a model for contemporary technologies.