23,782 research outputs found
Direct use of linear time-domain aerodynamics in aeroservoelastic analysis: Aerodynamic model
The work presented here is the first part of a continuing effort to expand existing capabilities in aeroelasticity by developing the methodology which is necessary to utilize unsteady time-domain aerodynamics directly in aeroservoelastic design and analysis. The ultimate objective is to define a fully integrated state-space model of an aeroelastic vehicle's aerodynamics, structure and controls which may be used to efficiently determine the vehicle's aeroservoelastic stability. Here, the current status of developing a state-space model for linear or near-linear time-domain indicial aerodynamic forces is presented
STRATEGIC PLANNING FOR IMPROVED COMPETITIVENESS BY REGIONAL COMMODITY INDUSTRIES
Agribusiness,
Career progress and career barriers: Women MBA graduates in Canada and the UK
This article explores the career progress of female MBA graduates in Canada and the UK and the nature of career barriers experienced in each context. Results suggest that while Canadian women have similar career profiles to men, women in the UK lag behind their male counterparts after graduation from the course. At the same time, UK women encounter more intractable career barriers in the form of negative attitudes and prejudice. A model of the âMBA effectâ is proposed in terms of how the qualification may impact on career barriers. This incorporates three different types of barriers which are seen to operate at the individual level (person centred barriers) and at the intermediate/organizational level (organizational culture and attitudes, corporate practices) as well as, at the macro level, the impact of legislative frameworks. Results from the UK and Canadian surveys are discussed in relation to this model and in the context of feminist theory and women in management literature
Assessing the climate impacts of Chinese dietary choices using a telecoupled global food trade and local land use framework
Global emissions trajectories developed to meet the 2â°C temperature target are likely to rely on the widespread deployment of negative emissions technologies and/or the implementation of substantial terrestrial carbon sinks. Such technologies include afforestation, carbon capture and storage (CCS) and bioenergy with carbon capture and storage (BECCS), but mitigation options for agriculture appear limited. For example, using the Global Calculator tool (http://www.globalcalculator.org/), under a 2â°C pathway, the âforests and other land useâ sector is projected to become a major carbon sink, reaching -15 GtCO2e yr-1 by 2050, compared to fossil emissions of 21 GtCO2e yr-1. At the same time, rates of agricultural emissions remain static at about 6 GtCO2e yr-1, despite increasing demands for crop and livestock production to meet the forecast dietary demands of the growing and increasingly wealthy global population. Emissions in the Global Calculator are sensitive to the assumed global diet, and particularly to the level and type of meat consumption, which in turn drive global land use patterns and agricultural emissions. Here we assess the potential to use a modified down-scaled Global Calculator methodology embedded within the telecoupled global food trade framework, to estimate the agricultural emissions and terrestrial carbon stock impacts in China and Brazil, arising from a plausible range of dietary choices in China. These dietary choices are linked via telecoupling mechanisms to Brazilian crop production (e.g. Brazilian soy for Chinese animal feed provision) and drive land and global market dynamics. âSpill-overâ impacts will also be assessed using the EU and Malawi as case studies
On the thermal buffering of naturally ventilated buildings through internal thermal mass
In this paper we examine the role of thermal mass in buffering the interior temperature of a naturally ventilated building from the diurnal fluctuations in the environment. First, we show that the effective thermal mass which is in good thermal contact with the air is limited by the diffusion distance into the thermal mass over one diurnal temperature cycle. We also show that this effective thermal mass may be modelled as an isothermal mass. Temperature fluctuations in the effective thermal mass are attenuated and phase-shifted from those of the interior air, and therefore heat is exchanged with the interior air. The evolution of the interior air temperature is then controlled by the relative magnitudes of (i) the time for the heat exchange between the effective thermal mass and the air; (ii) the time for the natural ventilation to replace the air in the space with air from the environment; and (iii) the period of the diurnal oscillations of the environment. Through analysis and numerical solution of the governing equations, we characterize a number of different limiting cases. If the ventilation rate is very small, then the thermal mass buffers the interior air temperature from fluctuations in the environment, creating a near-isothermal interior. If the ventilation rate increases, so that there are many air changes over the course of a day, but if there is little heat exchange between the thermal mass and interior air, then the interior air temperature locks on to the environment temperature. If there is rapid thermal equilibration of the thermal mass and interior air, and a high ventilation rate, then both the thermal mass and the interior air temperatures lock on to the environment temperature. However, in many buildings, the more usual case is that in which the time for thermal equilibration is comparable to the period of diurnal fluctuations, and in which ventilation rates are moderate. In this case, the fluctuations of the temperature of the thermal mass lag those of the interior air, which in turn lag those of the environment. We consider the implications of these results for the use of thermal mass in naturally ventilated buildings
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Abductive reasoning in neural-symbolic learning systems
Abduction is or subsumes a process of inference. It entertains possible hypotheses and it chooses hypotheses for further scrutiny. There is a large literature on various aspects of non-symbolic, subconscious abduction. There is also a very active research community working on the symbolic (logical) characterisation of abduction, which typically treats it as a form of hypothetico-deductive reasoning. In this paper we start to bridge the gap between the symbolic and sub-symbolic approaches to abduction. We are interested in benefiting from developments made by each community. In particular, we are interested in the ability of non-symbolic systems (neural networks) to learn from experience using efficient algorithms and to perform massively parallel computations of alternative abductive explanations. At the same time, we would like to benefit from the rigour and semantic clarity of symbolic logic. We present two approaches to dealing with abduction in neural networks. One of them uses Connectionist Modal Logic and a translation of Horn clauses into modal clauses to come up with a neural network ensemble that computes abductive explanations in a top-down fashion. The other combines neural-symbolic systems and abductive logic programming and proposes a neural architecture which performs a more systematic, bottom-up computation of alternative abductive explanations. Both approaches employ standard neural network architectures which are already known to be highly effective in practical learning applications. Differently from previous work in the area, our aim is to promote the integration of reasoning and learning in a way that the neural network provides the machinery for cognitive computation, inductive learning and hypothetical reasoning, while logic provides the rigour and explanation capability to the systems, facilitating the interaction with the outside world. Although it is left as future work to determine whether the structure of one of the proposed approaches is more amenable to learning than the other, we hope to have contributed to the development of the area by approaching it from the perspective of symbolic and sub-symbolic integration
CUSTOMER PREFERENCES FOR MICHIGAN APPLES: A CASE EXAMPLE OF A MARKET RESEARCH PROGRAM FOR A COMMODITY INDUSTRY
A series of market-research studies on Michigan apples are discussed in this paper. They provide a case example of a continuing program of market research to aid this industry. These include studies on changing preferences, needs, perceptions, practices and buying behavior for major customer segments of this industry, including consumers and grocery retailers, as well as mid-chain customer segments such as shippers and processors. While this market research program includes several component studies, the overall integration of the information from the various component studies is especially important for the development of the industry's marketing strategies. The component studies which comprise the overall market research program to date include the following interrelated phases: 1. An initial survey of apple shippers as key mid-chain firms - emphasizing overview information on customer needs and preferences as well as priorities for needed market research information. 2. A consumer focus group study. 3. A large-sample consumer telephone survey on consumer preferences, behavior and attitudes. 4. Consumer taste tests emphasizing fruit firmness and taste. 5. Consumer visual test regarding purchase preferences for fruit size and color. 6. A survey of consumers using an in-store taste and sampling program. 7. A follow-up survey of shippers that concentrated on apple varieties preferred for current and future markets. 8. A similar survey of apple processors on apple varieties preferred for processed apple markets. 9. A survey of grocery trade customers on their needs and preferences for fresh apples. 10. Integrative analyses comparing and contrasting preference information obtained from the studies listed in 1-9. The market research was done as part of broad-scope industry efforts to analyze, target and develop major strategic directions intended to position the industry for high performance and success in the future. These identified strategic directions have the goal of improving the industry's overall performance, including effectively meeting the needs of their consumer and trade customers in order to improve industry's competitiveness and economic viability. The specific types of information, priority questions and customer targets for each of the component market-research studies were developed in close cooperation with industry leaders and major industry organizations such as the industry's generic promotional commission. The industry has used the information from these market-research studies to develop their evolving strategies to most effectively serve their customer needs and hence to compete in the changing markets for their industry.Consumer/Household Economics,
IMPROVING VERTICAL COORDINATION OF AGRICULTURAL INDUSTRIES THROUGH SUPPLY CHAIN MANAGEMENT
Supply chain management is an important topic related to improving efficiency, vertical coordination, overall performance and competitiveness in food industries. Considerable attention has been given to supply chain management as an approach for improving vertical coordination and market performance in both the trade literature and by food economists. Much of this has been primarily from the perspective of grocery retailer-wholesalers, food manufacturers and their suppliers. Supply chain management is also very relevant, with substantial opportunities for improved efficiency and performance, if the perspective is from an agricultural commodity industry. The goal for a commodity industry in this regard is to find ways to enhance their responsiveness to their customers, and ultimately their competitiveness. This can be accomplished when two or more vertical segments together pursue innovative approaches to doing business with emphasis on the vertical linkages that mutually benefit all parties.Industrial Organization,
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