955 resultados para Set theory.


Relevância:

30.00% 30.00%

Publicador:

Resumo:

In this paper we review recent theoretical approaches for analysing the dynamics of on-line learning in multilayer neural networks using methods adopted from statistical physics. The analysis is based on monitoring a set of macroscopic variables from which the generalisation error can be calculated. A closed set of dynamical equations for the macroscopic variables is derived analytically and solved numerically. The theoretical framework is then employed for defining optimal learning parameters and for analysing the incorporation of second order information into the learning process using natural gradient descent and matrix-momentum based methods. We will also briefly explain an extension of the original framework for analysing the case where training examples are sampled with repetition.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

The performance of "typical set (pairs) decoding" for ensembles of Gallager's linear code is investigated using statistical physics. In this decoding method, errors occur, either when the information transmission is corrupted by atypical noise, or when multiple typical sequences satisfy the parity check equation as provided by the received corrupted codeword. We show that the average error rate for the second type of error over a given code ensemble can be accurately evaluated using the replica method, including the sensitivity to message length. Our approach generally improves the existing analysis known in the information theory community, which was recently reintroduced in IEEE Trans. Inf. Theory 45, 399 (1999), and is believed to be the most accurate to date. © 2002 The American Physical Society.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

The whole set of the nickel(II) complexes with no derivatized edta-type hexadentate ligands has been investigated from their structural and electronic properties. Two more complexes have been prepared in order to complete the whole set: trans(O5)-[Ni(ED3AP)]2- and trans(O5O6)-[Ni(EDA3P)]2- complexes. trans(O5) geometry has been verified crystallographically and trans(O5O6) geometry of the second complex has been predicted by the DFT theory and spectral analysis. Mutual dependance has been established between: the number of the five-membered carboxylate rings, octahedral/tetrahedral deviation of metal-ligand/nitrogen-neighbour-atom angles and charge-transfer energies (CTE) calculated by the Morokuma’s energetic decomposition analysis; energy of the absorption bands and HOMO–LUMO gap.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

What does endogenous growth theory tell about regional economies? Empirics of R&D worker-based productivity growth, Regional Studies. Endogenous growth theory emerged in the 1990s as ‘new growth theory accounting for technical progress in the growth process. This paper examines the role of research and development (R&D) workers underlying the Romer model (1990) and its subsequent modifications, and compares it with a model based on the accumulation of human capital engaged in R&D. Cross-section estimates of the models against productivity growth of European regions in the 1990s suggest that each R&D worker has a unique set of knowledge while his/her contributions are enhanced by knowledge sharing within a region as well as spillovers from other regions in proximity.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Previous developments in the opportunism-independent theory of the firm are either restricted to special cases or are derived from the capabilities or resource-based perspective. However, a more general opportunism-independent approach can be developed, based on the work of Demsetz and Coase, which is nevertheless contractual in nature. This depends on 'direction', that is, deriving economic value by permitting one set of actors to direct the activities of another, and of non-human factors of production. Direction helps to explain not only firm boundaries and organisation, but also the existence of firms, without appealing to opportunism or moral hazard. The paper also considers the extent to which it is meaningful to speak of 'contractual' theories in the absence of opportunism, and whether this analysis can be extended beyond the employment contract to encompass ownership of assets by the firm. © The Author 2005. Published by Oxford University Press on behalf of the Cambridge Political Economy Society. All rights reserved.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Purpose – The purpose of this editorial is to bring together thoughts and opinions from the Editors and Senior Advisory Board of EJM regarding the nature of the long-debated “theory-practice divide” in marketing scholarship. Design/methodology/approach – The authors synthesise diverse opinions from senior academics in order both to inspire further debate in marketing scholarship, and to draw some important conclusions for marketing academia as a whole. Findings – The authors propose that, for marketing scholarship to mature and progress, room must be found for those who wish to focus both on practical and on pure marketing scholarship. Career advancement from both routes is vital. Research limitations/implications – The topic of the theory-practice gap is complex. Many diverse opinions are cited and, due to space constraints, the coverage of many issues is necessarily brief. Practical implications – Scholars should find the thoughts contained in the paper of significant interest. Originality/value – The paper appears to be the first to bring together such a set of diverse opinions on the subject, and to try to draw some overall pragmatic conclusions, while still recognising the multiplicity of valid thought in the area.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Interest is growing around the application of lean techniques to new product introduction (NPI). Although a relatively emergent topic compared with the application of ‘lean’ within the factory, since 2000 there has been an exponential rise in the literature on this subject. However, much of this work focuses on describing and extolling the virtues of the ‘Toyota approach’ to design. Therefore, by way of a stock take for the UK, the present authors' research has set out to understand how well lean product design practices have been adopted by leading manufacturers. This has been achieved by carrying out in-depth case studies with three carefully selected manufacturers of complex engineered products. This paper describes these studies, the detailed results and subsequent findings, and concludes that both the awareness and adoption of practices is generally embryonic and far removed from the theory advocated in the literature.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

DUE TO COPYRIGHT RESTRICTIONS ONLY AVAILABLE FOR CONSULTATION AT ASTON UNIVERSITY LIBRARY AND INFORMATION SERVICES WITH PRIOR ARRANGEMENT This study is about leadership in American Evangelical Churches, which as a sub-set of American Christianity, are growing, while American Christianity as a whole is in decline. As a result evangelicalism is quickly becoming the dominate iteration of American Christianity. It is anecdotal that well led churches grow while poorly led churches do not, yet no one has identified what leadership, in the evangelical church context, is. Researchers have investigated a number of aspects of church leadership (much of it without identifying whether or not the churches under investigation were evangelical or not) but no one has put forth a unified theory linking these aspects together. The purpose of this research is to address that gap and develop a theory that explains how evangelicals view leadership in their local churches. In this study of three churches, dissimilar in size and governance, a purely qualitative approach to data collection and analysis was employed. The study involved 60 interviews that sought points-of-view from top and mid-level leadership along with congregant followers. The study borrowed heavily from Glaser and Strauss (1967) Grounded Theory approach to data analysis. The results developed a theory which provides a unified explanation of how leadership actually works in the three evangelical churches. Several implications for practice are discussed as to the theory's usefulness as a method of leadership education and evaluation. An original discovery was found that an individual's incumbency within the organization was identified as a social power. Limitations to this research are the limitations generally imputed to purely qualitative research in that questions are raised about the theory's applicability to evangelical churches beyond the three studied. The suggestions for further research involve addressing those limitations

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Does entrepreneurial optimism affect business performance? Using a unique data set based on repeated survey design, we investigate this relationship empirically. Our measures of ëoptimismí and ërealismí are derived from comparing the turnover growth expectations of ...133 owners-managers with the actual outcomes one year later. Our results indicate that entrepreneurial optimists perform significantly better in terms of profits than pessimists. Moreover, it is the optimist-realist combination that performs best. We interpret our results using regulatory focus theory.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Does entrepreneurial optimism affect business performance? Using a unique data set based on repeated survey design, we investigate this relationship empirically. Our measures of ‘optimism’ and ‘realism’ are derived from comparing the turnover growth expectations of 133 owners-managers with the actual outcomes one year later. Our results indicate that entrepreneurial optimists perform significantly better in terms of profits than pessimists. Moreover, it is the optimist-realist combination that performs best. We interpret our results using regulatory focus theory.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

This paper proposes a more profound discussion of the philosophical underpins of sustainability than currently exists in the MOT literature and considers their influence on the construction of the theories on green operations and technology management. Ultimately, it also debates the link between theory and practice on this subject area. The paper is derived from insights gained in three research projects completed during the past twelve years, primarily involving the first author. From 2000 to 2002, an investigation using scenario analysis, aimed at reducing atmospheric pollution in urban centres by substituting natural gas for petrol and diesel, provided the first set of insights about public policy, environmental impacts, investment analysis, and technological feasibility. The second research project, from 2003 to 2005, using a survey questionnaire, was aimed at improving environmental performance in livestock farming and explored the issues of green supply chain scope, environmental strategy and priorities. Finally, the third project, from 2006 to 2011, investigated environmental decisions in manufacturing organisations through case study research and examined the underlying sustainability drivers and decision-making processes. By integrating the findings and conclusions from these projects, the link between philosophy, theory, and practice of green operations and technology management is debated. The findings from all these studies show that the philosophical debate seems to have little influence on theory building so far. For instance, although ‘sustainable development’ emphasises ‘meeting the needs of current and future generation’, no theory links essentiality and environmental impacts. Likewise, there is a weak link between theory and the practical issues of green operations and technology management. For example, the well-known ‘life-cycle analysis’ has little application in many cases because the life cycle of products these days is dispersed within global production and consumption systems and there are different stakeholders for each life cycle stage. The results from this paper are relevant to public policy making and corporate environmental strategy and decision making. Most of the past and current studies in the subject of green operations and sustainability management deal with only a single sustainability dimension at any one time. Here the value and originality of this paper lies in its integration between philosophy, theory, and practice of green technology and operations management.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

If history matters for organization theory, then we need greater reflexivity regarding the epistemological problem of representing the past; otherwise, history might be seen as merely a repository of ready-made data. To facilitate this reflexivity, we set out three epistemological dualisms derived from historical theory to explain the relationship between history and organization theory: (1) in the dualism of explanation, historians are preoccupied with narrative construction, whereas organization theorists subordinate narrative to analysis; (2) in the dualism of evidence, historians use verifiable documentary sources, whereas organization theorists prefer constructed data; and (3) in the dualism of temporality, historians construct their own periodization, whereas organization theorists treat time as constant for chronology. These three dualisms underpin our explication of four alternative research strategies for organizational history: corporate history, consisting of a holistic, objectivist narrative of a corporate entity; analytically structured history, narrating theoretically conceptualized structures and events; serial history, using replicable techniques to analyze repeatable facts; and ethnographic history, reading documentary sources "against the grain." Ultimately, we argue that our epistemological dualisms will enable organization theorists to justify their theoretical stance in relation to a range of strategies in organizational history, including narratives constructed from documentary sources found in organizational archives. Copyright of the Academy of Management, all rights reserved.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

In terms of binary relations the author analyses the task of an individual consumers’ choice on the teaching excerpts set. It is suggested to analyse the function of consumer’s value as additive reduction. For localization of the vector of weighting coefficients of additive reduction the procedures based on metrics of object distance towards the ideal point are suggested.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

This chapter contributes to the anthology on learning to research - researching to learn because it emphases a need to design curricula that enables living research, and on-going researcher development, rather than one that restricts student and staff activities, within a marketised approach towards time. In recent decades higher education (HE) has come to be valued for its contribution to the global economy. Referred to as the neo-liberal university, a strong prioritisation has been placed on meeting the needs of industry by providing a better workforce. This perspective emphasises the role of a degree in HE to secure future material affluence, rather than to study as an on-going investment in the self (Molesworth , Nixon & Scullion, 2009: 280). Students are treated primarily as consumers in this model, where through their tuition fees they purchase a product, rather than benefit from the transformative potential university education offers for the whole of life.Given that HE is now measured by the numbers of students it attracts, and later places into well-paid jobs, there is an intense pressure on time, which has led to a method where the learning experiences of students are broken down into discrete modules. Whilst this provides consistency, students can come to view research processes in a fragmented way within the modular system. Topics are presented chronologically, week-by-week and students simply complete a set of tasks to ‘have a degree’, rather than to ‘be learners’ (Molesworth , Nixon & Scullion, 2009: 277) who are living their research, in relation to their own past, present and future. The idea of living research in this context is my own adaptation of an approach suggested by C. Wright Mills (1959) in The Sociological Imagination. Mills advises that successful scholars do not split their work from the rest of their lives, but treat scholarship as a choice of how to live, as well as a choice of career. The marketised slant in HE thus creates a tension firstly, for students who are learning to research. Mills would encourage them to be creative, not instrumental, in their use of time, yet they are journeying through a system that is structured for a swift progression towards a high paid job, rather than crafted for reflexive inquiry, that transforms their understanding throughout life. Many universities are placing a strong focus on discrete skills for student employability, but I suggest that embedding the transformative skills emphasised by Mills empowers students and builds their confidence to help them make connections that aid their employability. Secondly, the marketised approach creates a problem for staff designing the curriculum, if students do not easily make links across time over their years of study and whole programmes. By researching to learn, staff can discover new methods to apply in their design of the curriculum, to help students make important and creative connections across their programmes of study.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Koopmans gyakorlati problémák megoldása során szerzett tapasztalatait általánosítva fogott hozzá a lineáris tevékenységelemzési modell kidolgozásához. Meglepődve tapasztalta, hogy a korabeli közgazdaságtan nem rendelkezett egységes, kellően egzakt termeléselmélettel és fogalomrendszerrel. Úttörő dolgozatában ezért - mintegy a lineáris tevékenységelemzési modell elméleti kereteként - lerakta a technológiai halmazok fogalmán nyugvó axiomatikus termeléselmélet alapjait is. Nevéhez fűződik a termelési hatékonyság és a hatékonysági árak fogalmának egzakt definíciója, s az egymást kölcsönösen feltételező viszonyuk igazolása a lineáris tevékenységelemzési modell keretében. A hatékonyság manapság használatos, pusztán műszaki szempontból értelmezett definícióját Koopmans csak sajátos esetként tárgyalta, célja a gazdasági hatékonyság fogalmának a bevezetése és elemzése volt. Dolgozatunkban a lineáris programozás dualitási tételei segítségével rekonstruáljuk ez utóbbira vonatkozó eredményeit. Megmutatjuk, hogy egyrészt bizonyításai egyenértékűek a lineáris programozás dualitási tételeinek igazolásával, másrészt a gazdasági hatékonysági árak voltaképpen a mai értelemben vett árnyékárak. Rámutatunk arra is, hogy a gazdasági hatékonyság értelmezéséhez megfogalmazott modellje az Arrow-Debreu-McKenzie-féle általános egyensúlyelméleti modellek közvetlen előzményének tekinthető, tartalmazta azok szinte minden lényeges elemét és fogalmát - az egyensúlyi árak nem mások, mint a Koopmans-féle hatékonysági árak. Végezetül újraértelmezzük Koopmans modelljét a vállalati technológiai mikroökonómiai leírásának lehetséges eszközeként. Journal of Economic Literature (JEL) kód: B23, B41, C61, D20, D50. /===/ Generalizing from his experience in solving practical problems, Koopmans set about devising a linear model for analysing activity. Surprisingly, he found that economics at that time possessed no uniform, sufficiently exact theory of production or system of concepts for it. He set out in a pioneering study to provide a theoretical framework for a linear model for analysing activity by expressing first the axiomatic bases of production theory, which rest on the concept of technological sets. He is associated with exact definition of the concept of production efficiency and efficiency prices, and confirmation of their relation as mutual postulates within the linear model of activity analysis. Koopmans saw the present, purely technical definition of efficiency as a special case; he aimed to introduce and analyse the concept of economic efficiency. The study uses the duality precepts of linear programming to reconstruct the results for the latter. It is shown first that evidence confirming the duality precepts of linear programming is equal in value, and secondly that efficiency prices are really shadow prices in today's sense. Furthermore, the model for the interpretation of economic efficiency can be seen as a direct predecessor of the Arrow–Debreu–McKenzie models of general equilibrium theory, as it contained almost every essential element and concept of them—equilibrium prices are nothing other than Koopmans' efficiency prices. Finally Koopmans' model is reinterpreted as a necessary tool for microeconomic description of enterprise technology.