5,736 research outputs found

    Temporal disorder in up-down symmetric systems

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    The effect of temporal disorder on systems with up-down Z2 symmetry is studied. In particular, we analyze two well-known families of phase transitions: the Ising and the generalized voter universality classes, and scrutinize the consequences of placing them under fluctuating global conditions. We observe that variability of the control parameter induces in both classes "Temporal Griffiths Phases" (TGP). These recently-uncovered phases are analogous to standard Griffiths Phases appearing in systems with quenched spatial disorder, but where the roles of space and time are exchanged. TGPs are characterized by broad regions in parameter space in which (i) mean first-passage times scale algebraically with system size, and (ii) the system response (e.g. susceptibility) diverges. Our results confirm that TGPs are quite robust and ubiquitous in the presence of temporal disorder. Possible applications of our results to examples in ecology are discussed

    Orbit determination and control for the European Student Moon Orbiter

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    This paper presents the preliminary navigation and orbit determination analyses for the European Student Moon Orbiter. The severe constraint on the total mission Delta nu and the all-day piggy-back launch requirement imposed by the limited available budget, led to the choice of using a low-energy transfer, more specifically a Weak Stability Boundary one, with a capture into an elliptic orbit around the Moon. A particular navigation strategy was devised to ensure capture and fulfil the requirement for the uncontrolled orbit stability at the Moon. This paper presents a simulation of the orbit determination process, based on an extended Kalman filter, and the navigation strategy applied to the baseline transfer of the 2011-2012 window. The navigation strategy optimally allocates multiple Trajectory Correction Manoeuvres to target a so-called capture corridor. The capture corridor is defined, at each point along the transfer, by back-propagating the set of perturbed states at the Moon that provides an acceptable lifetime of the lunar orbit. (C) 2012 Elsevier Ltd. All rights reserved

    The development of an analytical tool for integrating 'the voice of the consumer' in new product development

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    The development of new products and how the process is organised and managed within the firm is a key area in management research due to the high failure rate of new products and the consequent waste of limited resources. Developing new products and being innovative requires companies to have deep understanding of the consumer, the market and the environment but most importantly to effectively apply this knowledge in the development of new products that meet consumer's expectations. This paper aims at developing an innovative framework to incorporate the 'voice of consumer' at early stages of the new product development (NPD) process. To that end, the paper will consider the practical implementation of the Quality Function Deployment (QFD) in the development of new food products. QFD is considered as the most complete and comprehensive methodology for planning the goals of a stream of processes in order to align them with customer's requirements. QFD forces the design team to place customer needs in first place and ensures that this customer focus is kept through the NPD process. In doing so, QFD reduces two types of risks: first, the non- correspondence between product specifications and the wants of a predetermined target consumer group; and second, the risk that final products do not comply with product specifications. To date, QFD has been partially applied in the food area with only a handful of studies venturing in this research area.quality function deployment, new product development, voice of consumer., Consumer/Household Economics, Demand and Price Analysis,

    An exploratory social network analysis of academic research networks

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    For several decades, academics around the world have been collaborating with the view to support the development of their research domain. Having said that, the majority of scientific and technological policies try to encourage the creation of strong inter-related research groups in order to improve the efficiency of research outcomes and subsequently research funding allocation. In this paper, we attempt to highlight and thus, to demonstrate how these collaborative networks are developing in practice. To achieve this, we have developed an automated tool for extracting data about joint article publications and analyzing them from the perspective of social network analysis. In this case study, we have limited data from works published in 2010 by England academic and research institutions. The outcomes of this work can help policy makers in realising the current status of research collaborative networks in England

    Analysis of Consumer Perceptions on Quality and Food Safety in the Spanish Beef Market: A Future Application in New Product Development

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    During the last years, the research of food quality perception and food safety have been issue of greater attention due to the intense existing debate on aspects related to ethical considerations relative to the new agricultural production techniques, animal welfare concerns, food scares and crises and their impact in consumer's confidence, that have brought numerous questions about quality and food safety. With the Total Food Quality Model as a point of departure, this study proposes an analysis of quality perception and food safety related to beef in Spain. The objective of this paper is to focus on the focus group technique and the qualitative research, using NVivo software for the handling, analysing and interpretation of qualitative data. Results indicate the more significant factors for habits of purchase, place of shopping, quality and food safety perception, role and confidence on brands and willingness to pay for certified beef. Some of the outcomes are supported by the quantitative research results, which is currently in progress.focus groups, NVivo software, quality perception, food choice and food safety, Consumer/Household Economics, Q13,

    El metabolismo social y los conflictos socio-ambientales en la India

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    This paper explains the methods for counting the energy and material flows in the economy, and gives the main results of the Material Flows for the economy of India between 1961 and 2008 as researched by Simron Singh et al (2012). Drawing on work done in the EJOLT project, some illustrations are given of the links between the changing social metabolism and ecological distribution conflicts, looking at responses in Odisha to bauxite mining, at conflicts on sand mining, at disputes on waste management options in Delhi and at ship dismantling in Alang, Gujarat. The aim is to show how a history of social metabolism, of socio-environmental conflicts, and of the changing valuation languages deployed by various social actors in such conflicts, could be written in a common framework.Este artículo explica los métodos seguidos para calcular los flujos de energía y de materiales en cualquier economía, y da los resultados (de Singh y otros, 2012) de los cálculos de Flujos de Materiales en la India desde 1961 hasta 2008. Incorporando investigaciones realizadas en el proyecto EJOLT, mostramos la conexión entre el cambiante metabolismo social y los conflictos de distribución ecológica, con las protestas en Odisha sobre la minería de bauxita, los conflictos sobre la “minería” de arena en varios lugares de la India, los debates sobre la gestión de la basura en Delhi, y el desguace de barcos en Alang, Gujarat. Nuestro objetivo es combinar en un solo marco la historia del metabolismo social y la historia de los conflictos socio-ambientales y los distintos lenguajes de valoración usados por los actores sociales de tales conflictos

    Species exclusion and coexistence in a noisy voter model with a competition-colonization tradeoff

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    We introduce an asymmetric noisy voter model to study the joint effect of immigration and a competition-dispersal tradeoff in the dynamics of two species competing for space in regular lattices. Individuals of one species can invade a nearest-neighbor site in the lattice, while individuals of the other species are able to invade sites at any distance but are less competitive locally, i.e., they establish with a probability g1g \le 1. The model also accounts for immigration, modeled as an external noise that may spontaneously replace an individual at a lattice site by another individual of the other species. This combination of mechanisms gives rise to a rich variety of outcomes for species competition, including exclusion of either species, mono-stable coexistence of both species at different population proportions, and bi-stable coexistence with proportions of populations that depend on the initial condition. Remarkably, in the bi-stable phase, the system undergoes a discontinuous transition as the intensity of immigration overcomes a threshold, leading to a half loop dynamics associated to a cusp catastrophe, which causes the irreversible loss of the species with the shortest dispersal range.Comment: 13 pages, 9 figures, 3 appendice

    Quality Function Deployment: Can Improve Innovation Efficiency in the Food Industry?

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    This paper considers the implementation of the Quality Function Deployment (QFD) as a methodological framework for the development of new food products. This paper focuses on the beef supply chain and develops a horizontal product’s quality deployment as a strategic tool for the implementation of consumer-led product innovation strategies. Difficulties in the prioritisation of parameters and setting of target values for the desired performance level of each parameter would limit the implementation of a complete ‘four-phase’ model in the sector. Thus, the use of complementary management tools, such as SWOT analysis and Failure Mode and Effect Analysis (FMEA) would be necessary to develop more suitable process designs to the specific requirements of the sector.Agribusiness, Research and Development/Tech Change/Emerging Technologies,

    The impact of evaporatively cooled turbine blades on gas turbine performance

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    Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 1995.Includes bibliographical references (leaf 58).by Federico Martinez-Tamayo.M.S
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