Network learning:an empirically-derived conceptual model of learning by groups of organizations

Building on a previous conceptual article, we present an empirically derived model of network learning - learning by a group of organizations as a group. Based on a qualitative, longitudinal, multiple-method empirical investigation, five episodes of network learning were identified. Treating each episode as a discrete analytic case, through cross-case comparison, a model of network learning is developed which reflects the common, critical features of the episodes. The model comprises three conceptual themes relating to learning outcomes, and three conceptual themes of learning process. Although closely related to conceptualizations that emphasize the social and political character of organizational learning, the model of network learning is derived from, and specifically for, more extensive networks in which relations among numerous actors may be arms-length or collaborative, and may be expected to change over time.

Dynamics of on-line learning in radial basis function networks

On-line learning is examined for the radial basis function network, an important and practical type of neural network. The evolution of generalization error is calculated within a framework which allows the phenomena of the learning process, such as the specialization of the hidden units, to be analyzed. The distinct stages of training are elucidated, and the role of the learning rate described. The three most important stages of training, the symmetric phase, the symmetry-breaking phase, and the convergence phase, are analyzed in detail; the convergence phase analysis allows derivation of maximal and optimal learning rates. As well as finding the evolution of the mean system parameters, the variances of these parameters are derived and shown to be typically small. Finally, the analytic results are strongly confirmed by simulations.

Integrated analytic hierarchy process and its applications:a literature review

Due to its wide applicability and ease of use, the analytic hierarchy process (AHP) has been studied extensively for the last 20 years. Recently, it is observed that the focus has been confined to the applications of the integrated AHPs rather than the stand-alone AHP. The five tools that commonly combined with the AHP include mathematical programming, quality function deployment (QFD), meta-heuristics, SWOT analysis, and data envelopment analysis (DEA). This paper reviews the literature of the applications of the integrated AHPs. Related articles appearing in the international journals from 1997 to 2006 are gathered and analyzed so that the following three questions can be answered: (i) which type of the integrated AHPs was paid most attention to? (ii) which area the integrated AHPs were prevalently applied to? (iii) is there any inadequacy of the approaches? Based on the inadequacy, if any, some improvements and possible future work are recommended. This research not only provides evidence that the integrated AHPs are better than the stand-alone AHP, but also aids the researchers and decision makers in applying the integrated AHPs effectively.

A methodology for analysis and control of discrete event dynamic systems

The rapid developments in computer technology have resulted in a widespread use of discrete event dynamic systems (DEDSs). This type of system is complex because it exhibits properties such as concurrency, conflict and non-determinism. It is therefore important to model and analyse such systems before implementation to ensure safe, deadlock free and optimal operation. This thesis investigates current modelling techniques and describes Petri net theory in more detail. It reviews top down, bottom up and hybrid Petri net synthesis techniques that are used to model large systems and introduces on object oriented methodology to enable modelling of larger and more complex systems. Designs obtained by this methodology are modular, easy to understand and allow re-use of designs. Control is the next logical step in the design process. This thesis reviews recent developments in control DEDSs and investigates the use of Petri nets in the design of supervisory controllers. The scheduling of exclusive use of resources is investigated and an efficient Petri net based scheduling algorithm is designed and a re-configurable controller is proposed. To enable the analysis and control of large and complex DEDSs, an object oriented C++ software tool kit was developed and used to implement a Petri net analysis tool, Petri net scheduling and control algorithms. Finally, the methodology was applied to two industrial DEDSs: a prototype can sorting machine developed by Eurotherm Controls Ltd., and a semiconductor testing plant belonging to SGS Thomson Microelectronics Ltd.

Quantifying simulator discrepancy in discrete-time dynamical simulators

When making predictions with complex simulators it can be important to quantify the various sources of uncertainty. Errors in the structural specification of the simulator, for example due to missing processes or incorrect mathematical specification, can be a major source of uncertainty, but are often ignored. We introduce a methodology for inferring the discrepancy between the simulator and the system in discrete-time dynamical simulators. We assume a structural form for the discrepancy function, and show how to infer the maximum-likelihood parameter estimates using a particle filter embedded within a Monte Carlo expectation maximization (MCEM) algorithm. We illustrate the method on a conceptual rainfall-runoff simulator (logSPM) used to model the Abercrombie catchment in Australia. We assess the simulator and discrepancy model on the basis of their predictive performance using proper scoring rules. This article has supplementary material online. © 2011 International Biometric Society.

A linguistic and semantic approach to the theory and practice of literary translation

This work explores the relevance of semantic and linguistic description to translation, theory and practice. It is aimed towards a practical model of approach to texts to translate. As literary texts [poetry mainly] are the focus of attention, so are stylistic matters. Note, however, that 'style', and, to some extent, the conclusions of the work, are not limited to so-called literary texts. The study of semantic description reveals that most translation problems do not stem from the cognitive (langue-related), but rather from the contextual (parole-related) aspects of meaning. Thus, any linguistic model that fails to account for the latter is bound to fall short. T.G.G. does, whereas Systemics, concerned with both the 'Iangue' and 'parole' (stylistic and sociolinguistic mainly) aspects of meaning, provides a useful framework of approach to texts to translate. Two essential semantic principles for translation are: that meaning is the property of a language (Firth); and the 'relativity of meaning assignments' (Tymoczko). Both imply that meaning can only be assessed, correctly, in the relevant socio-cultural background. Translation is seen as a restricted creation, and the translator's encroach as a three-dimensional critical one. To encompass the most technical to the most literary text, and account for variations in emphasis in any text, translation theory must be based on typology of function Halliday's ideational, interpersonal and textual, or, Buhler's symbol, signal, symptom, Functions3. Function Coverall and specific] will dictate aims and method, and also provide the critic with criteria to assess translation Faithfulness. Translation can never be reduced to purely objective methods, however. Intuitive procedures intervene, in textual interpretation and analysis, in the choice of equivalents, and in the reception of a translation. Ultimately, translation, theory and practice, may perhaps constitute the touchstone as regards the validity of linguistic and semantic theories.

Transducer diffraction theory and development of an ultrasonic tomogram

The work described in this thesis is the development of an ultrasonic tomogram to provide outlines of cross-sections of the ulna in vivo. This instrument, used in conjunction with X-ray densitometry previously developed in this department, would provide actual bone mineral density to a high resolution. It was hoped that the accuracy of the plot obtained from the tomogram would exceed that of existing ultrasonic techniques by about five times. Repeat measurements with these instruments to follow bone mineral changes would involve very low X-ray doses. A theoretical study has been made of acoustic diffraction, using a geometrical transform applicable to the integration of three different Green's functions, for axisymmetric systems. This has involved the derivation of one of these in a form amenable to computation. It is considered that this function fits the boundary conditions occurring in medical ultrasonography more closely than those used previously. A three dimensional plot of the pressure field using this function has been made for a ring transducer, in addition to that for disc transducers using all three functions. It has been shown how the theory may be extended to investigate the nature and magnitude of the particle velocity, at any point in the field, for the three functions mentioned. From this study. a concept of diffraction fronts has been developed, which has made it possible to determine energy flow also in a diffracting system. Intensity has been displayed in a manner similar to that used for pressure. Plots have been made of diffraction fronts and energy flow direction lines.

Oculomotor function in incipient presbyopia

The incipient phase of presbyopia represents a loss in accommodative amplitude of approximately 3 dioptres between the ages of 35 and 45 and is the prelude to the need for a reading addition. The need to maintain single binocular vision during this period requires re-calibration of the correspondence between accommodation and vergence response. No previous study has specifically attempted to correlate change in accommodative status with the profile of oculomotor responses occurring within the incipient phase of presbyopia. Measurements were made of the amplitude of accommodation, stimulus and response AC/A ratios, CA/C ratio, tonic accommodation, tonic vergence, proximal vergence, vergence adaptation and accommodative adaptation of 38 subjects. Twenty subjects were aged 35 to 45 years of age and 10 subjects were aged 20 to 30 years of age at the commencement of the study. The measurements were repeated at four-monthly intervals for a total of two years. The results of this study fail to support the Hess-Gullstrand theory of presbyopia with evidence that the effort to produce a unit change in accommodation increases with age. The data obtained has enabled the analysis of how each individual oculomotor function varies with the decline in amplitude of accommodation. MATLAB/SIMULINK software has been used to assist in the analysis and to allow the amendment of existing models to represent accurately the ageing oculomotor system. This study has proposed that with the decline in the amplitude of accommodation there is an increase in the accommodative convergence response per unit of accommodative response. To compensate for this increase, evidence has been found of a decrease in tonic vergence with age. If this decline in tonic vergence is not sufficient to counteract the increase in accommodative convergence, it is proposed that the near vision response is limited to the maximum vergence response that can be tolerated, with the resulting lower accommodative response being compensated for by an increase in the subjective depth-of-focus. When the blur due to the decrease in accommodative response can no longer be tolerated, the first reading addition will be required.

The role of industrial design in technological innovation

This is an exploratory study in a field which previously was virtually unexplored. The aim is to identify, for the benefit of innovators, the influence of industrial design on the commercial success of new science-based products used for professional and industrial purposes. The study is a contribution to the theory of success and failure in industrial innovation. The study begins by defining the terminology. To place the investigation in context, there is then a review of past attempts by official policy-making bodies to improve the competitiveness of British products of manufacture through good design. To elucidate the meaning of good design, attempts to establish a coherent philosophy of style in British products of manufacture during the same period are also reviewed. Following these reviews, empirical evidence is presented to identify what actually takes place in successful firms when industrial design is allocated a role in the process of technological innovation. The evidence comprises seven case studies of new science-based products used for professional or industrial purposes which have received Design Council Awards. To facilitate an objective appraisal, evidence was obtained by conducting separate semi-structured interviews, the detail of which is described, with senior personnel in innovating firms, with industrial design consultants, and with professional users. The study suggests that the likelihood of commercial success in technological innovation is greater when the form, configuration, and the overall appearance of a new product, together with the detail which delineates them, are consciously and expertly controlled. Moreover, uncertainty in innovation is likely to be reduced if the appearance of a new product is consciously designed to facilitate recognition and comprehension. Industrial design is an especially significant factor when a firm innovates against a background of international competition and comparable levels of technological competence in rival firms. The likelihood of success in innovation is enhanced if design is allocated a role closely identified with the total needs of the user and discrete from the engineering function in company organisation. Recent government measures, initiated since this study began, are corroborative of the findings.

Strategic logistics outsourcing:an integrated QFD and fuzzy AHP approach

This paper develops an integratedapproach, combining quality function deployment (QFD), fuzzy set theory, and analytic hierarchy process (AHP) approach, to evaluate and select the optimal third-party logistics service providers (3PLs). In the approach, multiple evaluating criteria are derived from the requirements of company stakeholders using a series of house of quality (HOQ). The importance of evaluating criteria is prioritized with respect to the degree of achieving the stakeholder requirements using fuzzyAHP. Based on the ranked criteria, alternative 3PLs are evaluated and compared with each other using fuzzyAHP again to make an optimal selection. The effectiveness of proposed approach is demonstrated by applying it to a Hong Kong based enterprise that supplies hard disk components. The proposed integratedapproach outperforms the existing approaches because the outsourcing strategy and 3PLs selection are derived from the corporate/business strategy.

Theory and data for area summation of contrast with and without uncertainty:evidence for a noisy energy model

Contrast sensitivity improves with the area of a sine-wave grating, but why? Here we assess this phenomenon against contemporary models involving spatial summation, probability summation, uncertainty, and stochastic noise. Using a two-interval forced-choice procedure we measured contrast sensitivity for circular patches of sine-wave gratings with various diameters that were blocked or interleaved across trials to produce low and high extrinsic uncertainty, respectively. Summation curves were steep initially, becoming shallower thereafter. For the smaller stimuli, sensitivity was slightly worse for the interleaved design than for the blocked design. Neither area nor blocking affected the slope of the psychometric function. We derived model predictions for noisy mechanisms and extrinsic uncertainty that was either low or high. The contrast transducer was either linear (c1.0) or nonlinear (c2.0), and pooling was either linear or a MAX operation. There was either no intrinsic uncertainty, or it was fixed or proportional to stimulus size. Of these 10 canonical models, only the nonlinear transducer with linear pooling (the noisy energy model) described the main forms of the data for both experimental designs. We also show how a cross-correlator can be modified to fit our results and provide a contemporary presentation of the relation between summation and the slope of the psychometric function.

On the theory of self-similar parabolic optical pulses

Self-similar optical pulses (or “similaritons”) of parabolic intensity profile can be found as asymptotic solutions of the nonlinear Schr¨odinger equation in a gain medium such as a fiber amplifier or laser resonator. These solutions represent a wide-ranging significance example of dissipative nonlinear structures in optics. Here, we address some issues related to the formation and evolution of parabolic pulses in a fiber gain medium by means of semi-analytic approaches. In particular, the effect of the third-order dispersion on the structure of the asymptotic solution is examined. Our analysis is based on the resolution of ordinary differential equations, which enable us to describe the main properties of the pulse propagation and structural characteristics observable through direct numerical simulations of the basic partial differential equation model with sufficient accuracy.

The propensity to disrupt and the disruption nucleolus of a characteristic function game

Gately [1974] recently introduced the concept of an individual player's “propensity to disrupt” a payoff vector in a three-person characteristic function game. As a generalisation of this concept we propose the “disruption nucleolus” of ann-person game. The properties and computational possibilities of this concept are analogous to those of the nucleolus itself. Two numerical examples are given.

Does metabolic reprogramming underpin age-associated changes in T cell phenotype and function?

T cells are required for an effective adaptive immune response. The principal function of T cells is to promote efficient removal of foreign material by identifying and mounting a specific response to nonself. A decline in T cell function in aging is thought to contribute to reduced response to infection and vaccination and an increase in autoimmunity. This may in part be due to the age-related decrease in naïve CD4+ T cells and increase in antigen-experienced CD4+ T cells, loss of redox homeostasis, and impaired metabolic switching. Switching between subsets is triggered by the integration of extracellular signals sensed through surface receptors and the activation of discrete intracellular metabolic pathways. This article explores how metabolic programming and loss of redox homeostasis during aging may contribute to age-associated changes in T cell phenotype and function. © 2014 Elsevier Inc.