COMUNICAÇÃO EM LINHA E RUÍDOS SEMÂNTICOS NA RECUPERAÇÃO DE INFORMAÇÕES EM PESQUISAS CIENTÍFICAS

O pesquisador científico necessita de informações precisas, em tempo hábil para conclusão de seus trabalhos. Com o advento da INTERNET, o processo de comunicação em linha, homem x máquina, mediado pelos mecanismos de busca, tornou-se, simultaneamente, um auxílio e uma dificuldade no processo de recuperação de informações. O pesquisador teve que adaptar-se ao modo de operar da INTERNET e incluiu conhecimentos de diferenças idiomáticas, de terminologia, além de utilizar instrumentos que lhe forneçam parâmetros para obter maior pertinência e relevância nos dados. O uso de agentes inteligentes para melhoria de resultados e a diminuição de ruídos semânticos têm sido apontados como soluções para aumento da precisão no resultado das buscas. O estudo de casos exploratório realizado analisa a pesquisa em linha a partir da teoria da informação e propõe duas formas de otimizar o processo comunicacional com vistas à pertinência e relevância dos dados obtidos: a primeira sugere a aplicação de algoritmos que utilizem o vocabulário controlado como mediador do processo de comunicação utilizando-se dos descritores para recuperação em linha. , e a segunda ressalta a importância dos agentes inteligentes no processo de comunicação homem-máquina.(AU)

Bayesian inference for wind field retrieval

In many problems in spatial statistics it is necessary to infer a global problem solution by combining local models. A principled approach to this problem is to develop a global probabilistic model for the relationships between local variables and to use this as the prior in a Bayesian inference procedure. We show how a Gaussian process with hyper-parameters estimated from Numerical Weather Prediction Models yields meteorologically convincing wind fields. We use neural networks to make local estimates of wind vector probabilities. The resulting inference problem cannot be solved analytically, but Markov Chain Monte Carlo methods allow us to retrieve accurate wind fields.

Delay estimation for multivariate time series

Most traditional methods for extracting the relationships between two time series are based on cross-correlation. In a non-linear non-stationary environment, these techniques are not sufficient. We show in this paper how to use hidden Markov models (HMMs) to identify the lag (or delay) between different variables for such data. We first present a method using maximum likelihood estimation and propose a simple algorithm which is capable of identifying associations between variables. We also adopt an information-theoretic approach and develop a novel procedure for training HMMs to maximise the mutual information between delayed time series. Both methods are successfully applied to real data. We model the oil drilling process with HMMs and estimate a crucial parameter, namely the lag for return.

Bayesian inference for wind field retrieval

In many problems in spatial statistics it is necessary to infer a global problem solution by combining local models. A principled approach to this problem is to develop a global probabilistic model for the relationships between local variables and to use this as the prior in a Bayesian inference procedure. We show how a Gaussian process with hyper-parameters estimated from Numerical Weather Prediction Models yields meteorologically convincing wind fields. We use neural networks to make local estimates of wind vector probabilities. The resulting inference problem cannot be solved analytically, but Markov Chain Monte Carlo methods allow us to retrieve accurate wind fields.

Mathematical modelling and control of agitated extraction columns

Liquid-liquid extraction has long been known as a unit operation that plays an important role in industry. This process is well known for its complexity and sensitivity to operation conditions. This thesis presents an attempt to explore the dynamics and control of this process using a systematic approach and state of the art control system design techniques. The process was studied first experimentally under carefully selected. operation conditions, which resembles the ranges employed practically under stable and efficient conditions. Data were collected at steady state conditions using adequate sampling techniques for the dispersed and continuous phases as well as during the transients of the column with the aid of a computer-based online data logging system and online concentration analysis. A stagewise single stage backflow model was improved to mimic the dynamic operation of the column. The developed model accounts for the variation in hydrodynamics, mass transfer, and physical properties throughout the length of the column. End effects were treated by addition of stages at the column entrances. Two parameters were incorporated in the model namely; mass transfer weight factor to correct for the assumption of no mass transfer in the. settling zones at each stage and the backmixing coefficients to handle the axial dispersion phenomena encountered in the course of column operation. The parameters were estimated by minimizing the differences between the experimental and the model predicted concentration profiles at steady state conditions using non-linear optimisation technique. The estimated values were then correlated as functions of operating parameters and were incorporated in·the model equations. The model equations comprise a stiff differential~algebraic system. This system was solved using the GEAR ODE solver. The calculated concentration profiles were compared to those experimentally measured. A very good agreement of the two profiles was achieved within a percent relative error of ±2.S%. The developed rigorous dynamic model of the extraction column was used to derive linear time-invariant reduced-order models that relate the input variables (agitator speed, solvent feed flowrate and concentration, feed concentration and flowrate) to the output variables (raffinate concentration and extract concentration) using the asymptotic method of system identification. The reduced-order models were shown to be accurate in capturing the dynamic behaviour of the process with a maximum modelling prediction error of I %. The simplicity and accuracy of the derived reduced-order models allow for control system design and analysis of such complicated processes. The extraction column is a typical multivariable process with agitator speed and solvent feed flowrate considered as manipulative variables; raffinate concentration and extract concentration as controlled variables and the feeds concentration and feed flowrate as disturbance variables. The control system design of the extraction process was tackled as multi-loop decentralised SISO (Single Input Single Output) as well as centralised MIMO (Multi-Input Multi-Output) system using both conventional and model-based control techniques such as IMC (Internal Model Control) and MPC (Model Predictive Control). Control performance of each control scheme was. studied in terms of stability, speed of response, sensitivity to modelling errors (robustness), setpoint tracking capabilities and load rejection. For decentralised control, multiple loops were assigned to pair.each manipulated variable with each controlled variable according to the interaction analysis and other pairing criteria such as relative gain array (RGA), singular value analysis (SVD). Loops namely Rotor speed-Raffinate concentration and Solvent flowrate Extract concentration showed weak interaction. Multivariable MPC has shown more effective performance compared to other conventional techniques since it accounts for loops interaction, time delays, and input-output variables constraints.

Analytical techniques for the study of soft contact lens spoilation

Soft contact lens wear has become a common phenomenon in recent times. The contact lens when placed in the eye rapidly undergoes change. A film of biological material builds up on and in the lens matrix. The long term wear characteristics of the lens ultimately depend on this process. With time distinct structures made up of biological material have been found to build up on the lens. A fuller understanding of this process and how it relates to the lens chemistry could lead to contact lenses that are better tolerated by the eye. The tear film is a complex biological fluid, it is this fluid that bathes the lens during wear. It is reasonable to suppose that it is material derived from this source that accumulates on the lens. To understand this phenomenon it was decided to investigate the make up and conformation of the protein species that are found on and in the lens. As inter individual variations in tear fluid composition have been found it is important to be able to study the proteins on a single lens. Many of the analytical techniques used in bio research are not suitable for this study because of the lack of sensitivity. Work with poly acrylamide electrophoresis showed the possibility of analyzing the proteins extracted from a single lens. The development of a biotin avidin electro-blot and an enzyme linked aniibody electro-blot, lead to the high sensitivity detection and identification of the proteins present. The extraction of proteins from a lens is always incomplete. A method that analyses the proteins in situ would be a great advancement. Fourier transform infra red microscopy was developed to a point where a thin section of a contact lens could yield information about the proteins present and their conformation. The three dimensional structure of the gross macroscopic structures termed white spots was investigated using confocal laser microscopy.

Strategy and control systems:a framework for analysis

This research explores the links between the strategies adopted by companies and the mechanisms used to control the organisation. This is not seen as a one way process with the control system following from the strategy but rather as an interactive process between the control systems, the environment and the business strategy. The main proposition of the research, derived from a review of the relevant literature, is that the dimensions of Business Pro-Activity and Environmental Change provide a plausible explanation of the reasons why companies need to adopt different strategies in order to be successful in different markets. A model is proposed which links these dimensions with the business strategy, organisational structure, strategic planning system and management control systems. The model is used as a framework for analysing four companies in order to further our understanding of these interactions and the mechanisms which act to both promote and resist change. Whilst it is not suggested that the model in its present form is a perfect instrument it has, during the course of this research, proved to be an appropriate framework for analysing the various mechanisms used by four companies to formulate and implement their strategies. The research reveals that these should not be viewed independently but as a balanced system.

The contract management responsibility system in China : an institutional interpretation

Thesis is about the enterprise reform in China in general, and the Contract Management Responsibility System (the CMRS) in particular. The latter is a new institutional arrangement to deal with the relation between the government and the state-owned enterprise which has always been at the centre of the enterprise reform. The focus of the research is on the process of institutionalization in order to study the problems of the emergence of a free enterprise system in China. The research is conducted by four in-depth case studies to reveal how the CMRS is running and what interaction is taking place between the government and the state-owned enterprise under the system. Drawing on the empirical work, the thesis analyzes the features of the CMRS and the characteristics of its implementation process with respect to the structural-institutional paradigm, and the property rights approach. The research shows that to establish a market-type relation between the government and the enterprise is a complicated and dynamic process. It involves the understanding of the two different economic mechanisms, market and planning, and the interations taken by two parties. It concludes that the CMRS is an unstable system, either going back to the previous system or moving towards a market system, because its dynamic and control dimension are dysfunctional.

A study in Britain and France of the development of cross-cultural in-house sales training using distance learning.

The thesis is concerned with cross-cultural distance learning in two countries: Great Britain and France. Taking the example of in-house sales training, it argues that it is possible to develop courses for use in two or more countries of differing culture and language. Two courses were developed by the researcher. Both were essentially print-based distance-learning courses designed to help salespeople achieve a better understanding of their customers. One used a quantitative, the other qualitative approach. One considered the concept of the return on investment and the other, for which a video support was also developed, considered the analysis of a customer's needs. Part 1 of the thesis considers differences in the training context between France and Britain followed by a review of the learning process with reference to distance learning. Part 2 looks at the choice of training medium course design and evaluation and sets out the methodology adopted, including problems encountered in this type of fieldwork. Part 3 analyses the data and draws conclusions from the findings, before offering a series of guidelines for those concerned with the development of cross-cultural in-house training courses. The results of the field tests on the two courses were analysed in relation to the socio-cultural, educational and experiential background of the learners as well as their preferred learning styles. The thesis argues that it is possible to develop effective in-house sales training courses to be used in two cultures and identifies key considerations which need to be taken into account when carrying out this type of work.

The Mechanics of the drawing of polygonal sections from round at elevated temperature

Economic factors such as the rise in cost of raw materials, labour and power, are compelling manufacturers of cold-drawn polygonal sections, to seek new production routes which will enable the expansion in the varieties of metals used and the inclusion of difficult-to-draw materials. One such method generating considerable industrial interest is the drawing of polygonal sections from round at elevated temperature. The technique of drawing mild steel, medium carbon steel and boron steel wire into octagonal, hexagonal and square sections from round at up to 850 deg C and 50% reduction of area in one pass has been established. The main objective was to provide a basic understanding of the process, with particular emphasis being placed on modelling using both experimental and theoretical considerations. Elevated temperature stress-strain data was obtained using a modified torsion testing machine. Data were used in the upper bound solution derived and solved numerically to predict drawing stress strain, strain-rate, temperature and flow stress distribution in the deforming zone for a range of variables. The success of this warm working process will, of course, depend on the use of a satisfactory elevated temperature lubricant, an efficient cooling system, a suitable tool material having good wear and thermal shock resistance and an efficient die profile design which incorporates the principle of least work. The merits and demerits of die materials such as tungsten carbide, chromium carbide, Syalon and Stellite are discussed, principally from the standpoint of minimising drawing force and die wear. Generally, the experimental and theoretical results were in good agreement, the drawing stress could be predicted within close limits and the process proved to be technically feasible. Finite element analysis has been carried out on the various die geometries and die materials, to gain a greater understanding of the behaviour of these dies under the process of elevated temperature drawing, and to establish the temperature distribution and thermal distortion in the deforming zone, thus establishing the optimum die design and die material for the process. It is now possible to predict, for the materials already tested, (i) the optimum drawing temperature range, (ii) the maximum possible reduction of area per pass, (iii) the optimum drawing die profiles and die materials, (iv) the most efficient lubricant in terms of reducing the drawing force and die wear.

A study of the calcium-induced morphological transistions of human erythrocytes

An examination was made of the morphological transitions induced in human erythrocytes by the elevation of cytosolic calcium, and of the biochemical mechanisms responsible. The loss of the discocyte morphology and the sequential progression of cells through the echinocyte stages 1, 2, 3 and sphereo-echinocyte was found to occur in both a calcium concentration- and a time-dependent manner. SDS-PAGE analysis of cytoskeletal proteins prepared from intact cells loaded with 150uM or 1mM calcium revealed the partial proteolytic loss of proteins 2.1, 2.2 and 4.1. The rate of proteolysis was not paralleled by that of echinocytosis, making a causative relationship unlikely. Cytoskeletal integrity did appear to influence shape reversal from the echinocyte to the discocyte morphology after removal of the calcium and ionophore A23187. The loss of 80% protein 4.1, 40% 2.1 and 30% 2.2 was associated with, although not necessarily the sole cause, of irreversible sphereo-echinocytosis. Pre-treatment of cells with wheat germ agglutinin preserved the discocyte morphology despite continued cytoskeletal proteolysis during calcium-loading. All observations were made on cells incubated either in the presence or absence of glycolytic substrates, effectively altering cell metabolic status. This influenced the rate of progression of cells through the echinocyte stages, the rate of proteolysis of cytoskeletal proteins, and the extent and kinetics of shape reversal from cells transformed to the sphereo-echinocyte morphology. The stage 1 to discocyte transition was the rate limiting step of this shape recovery. In contrast the rate of loss of the discocyte morphology was independent of cell metabolic status during exposure to calcium, as was the extent of restoration of the discocyte morphology from cells transformed to stage 1 echinocytes. An hypothesis is presented that echinocytosis is a discontinuous process with discrete steps initiated by different biochemical mechanisms varying in their dependence on metabolic energy.

Contrast integration over area is extensive: a three-stage model of spatial summation

Classical studies of area summation measure contrast detection thresholds as a function of grating diameter. Unfortunately, (i) this approach is compromised by retinal inhomogeneity and (ii) it potentially confounds summation of signal with summation of internal noise. The Swiss cheese stimulus of T. S. Meese and R. J. Summers (2007) and the closely related Battenberg stimulus of T. S. Meese (2010) were designed to avoid these problems by keeping target diameter constant and modulating interdigitated checks of first-order carrier contrast within the stimulus region. This approach has revealed a contrast integration process with greater potency than the classical model of spatial probability summation. Here, we used Swiss cheese stimuli to investigate the spatial limits of contrast integration over a range of carrier frequencies (1–16 c/deg) and raised plaid modulator frequencies (0.25–32 cycles/check). Subthreshold summation for interdigitated carrier pairs remained strong (~4 to 6 dB) up to 4 to 8 cycles/check. Our computational analysis of these results implied linear signal combination (following square-law transduction) over either (i) 12 carrier cycles or more or (ii) 1.27 deg or more. Our model has three stages of summation: short-range summation within linear receptive fields, medium-range integration to compute contrast energy for multiple patches of the image, and long-range pooling of the contrast integrators by probability summation. Our analysis legitimizes the inclusion of widespread integration of signal (and noise) within hierarchical image processing models. It also confirms the individual differences in the spatial extent of integration that emerge from our approach.

Petrology of weathered lower lias clays

In weak argillaceous rocks the unweathered strength may be barely sufficient to meet civil engineering reguirements and any reductjon due to weathering will be critical. This study investigates the weathering of the Lower Lias clays with particular reference to their petrography and engineering properties. Investigations revealed the Midland Basin of deposition to contain reasonable thicknesses of clay, relatively uniform in nature with a well developed weathered zone, From the available exposures, the weathering zone of the Blockley Clay pit was selected and sampled for laboratory investigations of; Structure, Mineralogy and Chemistry and Engineering Properties. The nature and orientation of the fissures in the unweathered clay were analysed. A close relationship was found to exist between the major joint set and the ground surface, with stress release due to excavation being almost negligible. Thin sections of the clay, examined for structural data, suggested that there exist layers or areas that have been disturbed as a result of density differences. Shear planes were found in both the unweathered and weathered clay, in the latter case often associated with remoulding of the material. A direct measure of remoulding was obtained from the birefringence ratio. The fabric was examined in closer detail using the scanning electron microscope. Mineralogy, as revealed by X-ray and optical techniques indicated illite as the dominant clay mineral, with kaolinite subsidiary; quartz, calcite, pyrite, chlorite/vermiculite are present as accessory minerals. Weathering changes this relationship, calcite and pyrite being removed early in the process, with illite being degraded. The cementing action of calcite and iron oxides was investigated however, this was shown to be negligible. Quantitative measurements of both fixed (with minerals) and free (oxide coatings) iron were obtained by atomic absorption, with the Fe 3+/ Fe2+ ratio obtained by Mossbauer spectroscopy, Evidence indicates that free iron oxide coatings only become important as a result of weathering with the maximum concentration in the very highly weathered material. Engineering index properties and shear strength values were taken throughout the profile, Relationships between moisture content and strength, liquid limit and iron (Fe) were obtained and a correlation between the weathering zomes and the shear strength/depth curve has been established.

'Worlds of justification’ in the politics and practices of urban regeneration

A considerable body of research has developed on processes of neoliberal urban regeneration and gentrifi cation. On the one hand, there are many political economy accounts emphasising the role of economic capital in processes of urban change and gentrifi cation. On the other hand, there is a wealth of governmentality studies on the art of government that fail to explain how ungovernable subjects develop. Similarly, within gentrifi cation studies there are many accounts on the role of changing consumer lifestyles and defi ning gentrifi cation, but less concern with the governance processes between actors in urban regeneration and gentrifi cation. Yet such issues are of considerable importance given the role of the state in urban regeneration and dependence on private capital. This paper utilises the French Pragmatist approach of Boltanski and Thévenot to examine a case study state-led gentrifi cation project. Boltanski and Thévenot argue that social coordination occurs by way of actors working through broader value-laden ‘worlds of justifi cation’ that underpin processes of argumentation and coordination. The examined case study is a deprived area within an English city where a major state-led gentrification programme has been introduced. The rationale for the programme is based on the assumption that reducing deprivation relies upon substantially increasing the number of higher income earners. The paper concludes that market values have overridden broader civic values in the negotiation process, with this intensifying as the state internalised market crisis tendencies within the project. More broadly, there is a need for French Pragmatism to be more sensitive to the spatial processes of social coordination, which can be achieved through critical engagement with recent concepts of ‘assemblages’.

The experience of delivering case award research in a public sector setting

The CASE Award PhD is a relatively new approach to completing academic research degrees, aligning the ideals of comprehensive research training and cross-collaboration between academics and organisations. As the initial wave of CASE funded PhD research begins to near completion, and indeed become evident through the publication of results, now is an appropriate time to begin the evaluation process of how to successfully deliver a CASE PhD, and to analyse the best practice approaches of completing a CASE Award with an organisation. This article intends to offer a picture into the CASE PhD process, with a focus on methods of communication to successfully implement this kind of research in collaboration with an organisation.