13 resultados para f-k technique

em Aston University Research Archive


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Purpose. A clinical evaluation of the Shin-Nippon NVision-K 5001 (also branded as the Grand Seiko WR-5100K) autorefractor (Japan) was performed to examine validity and repeatability compared with subjective refraction and Javal-Schiotz keratometry. Methods. Measurements of refractive error were performed on 198 eyes of 99 subjects (aged 23.2 ± 7.4 years) subjectively (noncycloplegic) by one masked optometrist and objectively with the NVision-K autorefractor by a second optometrist. Keratometry measurements using the NVision-K were compared with the Javal-Schiotz keratometer. Intrasession repeatability of the NVision-K was also assessed on all 99 subjects together with intersession repeatability on a separate occasion separated by 7 to 14 days. Results. Refractive error as measured by the NVision-K was found to be similar (p = 0.67) to subjective refraction (difference, 0.14 ± 0.35 D). It was both accurate and repeatable over a wide prescription range (-8.25 to +7.25 D). Keratometry as measured by the NVision-K was found to be similar (p > 0.50) to the Javal-Schiotz technique in both the horizontal and vertical meridians (horizontal: difference, 0.02 ± 0.09 mm; vertical: difference, 0.01 ± 0.14 mm). There was minimal bias, and the results were repeatable (horizontal: intersession difference, 0.00 ± 0.09 mm; vertical: intersession difference, -0.01 ± 0.12 mm). Conclusion. The open-view arrangement of the Shin-Nippon NVision-K 5001 facilitates the measurement of static refractive error and the accommodative response to real-world stimuli. Coupled with its accuracy, repeatability, and capability to measure corneal curvature, it is a valuable addition to objective instrumentation currently available to the optometrist and researcher.

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The evaluation and selection of industrial projects before investment decision is customarily done using marketing, technical and financial information. Subsequently, environmental impact assessment and social impact assessment are carried out mainly to satisfy the statutory agencies. Because of stricter environment regulations in developed and developing countries, quite often impact assessment suggests alternate sites, technologies, designs, and implementation methods as mitigating measures. This causes considerable delay to complete project feasibility analysis and selection as complete analysis requires to be taken up again and again till the statutory regulatory authority approves the project. Moreover, project analysis through above process often results sub-optimal project as financial analysis may eliminate better options, as more environment friendly alternative will always be cost intensive. In this circumstance, this study proposes a decision support system, which analyses projects with respect to market, technicalities, and social and environmental impact in an integrated framework using analytic hierarchy process, a multiple-attribute decision-making technique. This not only reduces duration of project evaluation and selection, but also helps select optimal project for the organization for sustainable development. The entire methodology has been applied to a cross-country oil pipeline project in India and its effectiveness has been demonstrated. © 2005 Elsevier B.V. All rights reserved.

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The majority of the literature about CBM is American in origin, and (inter alia) notes that there were differing uses of similar technology, indicating that context has an important role to play in the use of CBM. The literature maps the psychological effects of CBM in considerable detail, but only two published studies examine the context of CBM. These grounded results provide scant support for any systematic, quantitative, large scale analysis of computer based monitoring in the UK context. This thesis thus aims to systemically examine the context of CBM using discourse analysis. Forty four interviewees were theoretically sampled using a structured sample technique in four organizations. All were national or multinational enterprises. The interviews were semi structured in nature and divided into three sections. The first addressed the respondents' thoughts and perceptions about CBM, the second elicited talk about the departmental context (focusing the management - worker relationship), and the final section addressed the organizational context. The cases demonstrated variation in the use of CBM, measured according to the criteria of Westin (1987, 1988) and according to the interpretive repertoires used by the respondents in each case. Seven analytical categories of talk emerged from the data: three at the organizational level and four at the departmental level of analysis. Discourse analysis revealed two discrete interpretive repertories - the procedural and the substantive repertoires - in respondents' talk whose main variation occurred at the departmental level of analysis. Furthermore, patterns were found in the use of these repertories within cases and between categories. Between the cases, variation in the use of the repertories matched the between case variation according to the criteria of Westin. It would thus appear that the source of variation in the use of CBM lies in its context, more specifically in the relative emphasis of humanistic, interpersonal and idiosyncratic values within the management worker relationship.

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Research was undertaken in the field of marketing strategy, its formulation and implementation in Dunlop Belting Division. Emphasis was placed on marketing channel strategy, but other strategies including product strategy were studied. The research has resulted in changes in management practice in the client organisation. The relevance of theories of company organisation, planning and strategy, and marketing channels was examined in the light of the research evidence. The technique of action-research was used to gain admittance to and effect change within the client organisation. Case study material was collected for subsequent analysis. The factors affecting marketing strategy formulation in the client organisation were studied. Both the external and the internal business environments were considered. The operation of the observed marketing channels was compared with channel theory. Market segmentation and penetration, and the selling and technical resources of the channels were analysed. Recommendations were made to (a) enlarge and resite the client's distribution unit to locate it centrally in England (b) use the resited unit to secure local advantage (c) obtain greater integration of field sales activities with and from the centre. A new ex-stock distribution unit was established. Improvements to the client's ex-stock marketing in Scotland were also recommended, including improvements to the Scottish distributor's stock control procedure, as well as to Dunlop-Distributor relationships at all levels. The influence of company organisation structure and formalised procedures and systems on the formulation of strategy were considered with respect to channel and product strategy, and other aspects of marketing. Conclusions were drawn that the action research resulted in successful implementation of .agreed changes in the client organisation; that theories of strategy formulation and planning, of the operation of decentralised companies, and of industrial market segmentation required modification; that the theory of marketing channels was found relevant and useful.

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We propose an all-optical passive 2R regeneration method for WDM (N×40 Gbit/s) dispersion-managed RZ transmission based on specially designed WDM guiding filters and in-line nonlinear optical loop mirrors. By system optimisation, the feasibility of 150 GHz-spaced × l6 channel transmission over 25,000 km of standard fibre is numerically demonstrated.

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We propose a passive all-optical 2R regeneration method for WDM (N×40 Gbit/s) dispersion-managed RZ transmission based on specially designed WDM guiding filters and in-line nonlinear optical loop mirrors. By system optimisation, the feasibility of 150 GHz-spaced × 16 channel 25000 km transmission over standard fibre is numerically demonstrated.

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This study proposes an integrated analytical framework for effective management of project risks using combined multiple criteria decision-making technique and decision tree analysis. First, a conceptual risk management model was developed through thorough literature review. The model was then applied through action research on a petroleum oil refinery construction project in the Central part of India in order to demonstrate its effectiveness. Oil refinery construction projects are risky because of technical complexity, resource unavailability, involvement of many stakeholders and strict environmental requirements. Although project risk management has been researched extensively, practical and easily adoptable framework is missing. In the proposed framework, risks are identified using cause and effect diagram, analysed using the analytic hierarchy process and responses are developed using the risk map. Additionally, decision tree analysis allows modelling various options for risk response development and optimises selection of risk mitigating strategy. The proposed risk management framework could be easily adopted and applied in any project and integrated with other project management knowledge areas.

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The accurate identification of T-cell epitopes remains a principal goal of bioinformatics within immunology. As the immunogenicity of peptide epitopes is dependent on their binding to major histocompatibility complex (MHC) molecules, the prediction of binding affinity is a prerequisite to the reliable prediction of epitopes. The iterative self-consistent (ISC) partial-least-squares (PLS)-based additive method is a recently developed bioinformatic approach for predicting class II peptide−MHC binding affinity. The ISC−PLS method overcomes many of the conceptual difficulties inherent in the prediction of class II peptide−MHC affinity, such as the binding of a mixed population of peptide lengths due to the open-ended class II binding site. The method has applications in both the accurate prediction of class II epitopes and the manipulation of affinity for heteroclitic and competitor peptides. The method is applied here to six class II mouse alleles (I-Ab, I-Ad, I-Ak, I-As, I-Ed, and I-Ek) and included peptides up to 25 amino acids in length. A series of regression equations highlighting the quantitative contributions of individual amino acids at each peptide position was established. The initial model for each allele exhibited only moderate predictivity. Once the set of selected peptide subsequences had converged, the final models exhibited a satisfactory predictive power. Convergence was reached between the 4th and 17th iterations, and the leave-one-out cross-validation statistical terms - q2, SEP, and NC - ranged between 0.732 and 0.925, 0.418 and 0.816, and 1 and 6, respectively. The non-cross-validated statistical terms r2 and SEE ranged between 0.98 and 0.995 and 0.089 and 0.180, respectively. The peptides used in this study are available from the AntiJen database (http://www.jenner.ac.uk/AntiJen). The PLS method is available commercially in the SYBYL molecular modeling software package. The resulting models, which can be used for accurate T-cell epitope prediction, will be made freely available online (http://www.jenner.ac.uk/MHCPred).

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Dynamic asset rating (DAR) is one of the number of techniques that could be used to facilitate low carbon electricity network operation. Previous work has looked at this technique from an asset perspective. This paper focuses, instead, from a network perspective by proposing a dynamic network rating (DNR) approach. The models available for use with DAR are discussed and compared using measured load and weather data from a trial network area within Milton Keynes in the central area of the U.K. This paper then uses the most appropriate model to investigate, through a network case study, the potential gains in dynamic rating compared to static rating for the different network assets - transformers, overhead lines, and cables. This will inform the network operator of the potential DNR gains on an 11-kV network with all assets present and highlight the limiting assets within each season.

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The nonlinear inverse synthesis (NIS) method, in which information is encoded directly onto the continuous part of the nonlinear signal spectrum, has been proposed recently as a promising digital signal processing technique for combating fiber nonlinearity impairments. However, because the NIS method is based on the integrability property of the lossless nonlinear Schrödinger equation, the original approach can only be applied directly to optical links with ideal distributed Raman amplification. In this paper, we propose and assess a modified scheme of the NIS method, which can be used effectively in standard optical links with lumped amplifiers, such as, erbium-doped fiber amplifiers (EDFAs). The proposed scheme takes into account the average effect of the fiber loss to obtain an integrable model (lossless path-averaged model) to which the NIS technique is applicable. We found that the error between lossless pathaveraged and lossy models increases linearly with transmission distance and input power (measured in dB). We numerically demonstrate the feasibility of the proposed NIS scheme in a burst mode with orthogonal frequency division multiplexing (OFDM) transmission scheme with advanced modulation formats (e.g., QPSK, 16QAM, and 64QAM), showing a performance improvement up to 3.5 dB; these results are comparable to those achievable with multi-step per span digital backpropagation.

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We report the fabrication of a refractive index (RI) sensor based on a liquid core fibre Bragg grating (FBG). A micro-slot FBG was created in standard telecom optical fibre employing the tightly focused femtosecond laser inscription aided chemical etching. A micro-slot with dimensions of 5.74(h) × 125(w) × 1388.72(l) μm was engraved across the whole fibre and along 1mm long FBG which gives advantage of a relatively robust liquid core waveguide. The device performed the refractive index sensitivity up to about 742.72 nm/RIU. © 2011 Copyright Society of Photo-Optical Instrumentation Engineers (SPIE).

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The solubility of telmisartan (form A) in nine organic solvents (chloroform, dichloromethane, ethanol, toluene, benzene, 2-propanol, ethyl acetate, methanol and acetone) was determined by a laser monitoring technique at temperatures from 277.85 to 338.35 K. The solubility of telmisartan (form A) in all of the nine solvents increased with temperature as did the rates at which the solubility increased except in chloroform and dichloromethane. The mole fraction solubility in chloroform is higher than that in dichloromethane, which are both one order of magnitude higher than those in the other seven solvents at the experimental temperatures. The solubility data were correlated with the modified Apelblat equation and λh equations. The results show that the λh equation is in better agreement with the experimental data than the Apelblat equation. The relative root mean square deviations (σ) of the λh equation are in the range from 0.004 to 0.45 %. The dissolution enthalpies, entropies and Gibbs energies of telmisartan in these solvents were estimated by the Van’t Hoff equation and the Gibbs equation. The melting point and the fusion enthalpy of telmisartan were determined by differential scanning calorimetry.