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1.
BACKGROUND: Interview studies which employ qualitative methodology are often concerned with classifying behaviours or attitudes and an ideal sample of research subjects displays variety in the attitudes or behaviours under scrutiny. OBJECTIVE: This paper describes the development of a questionnaire which measures GPs' attitudes towards discussing smoking with patients with the intention of using this instrument to select GPs with diverse views for a qualitative interview study. METHOD: Thirteen attitude statements with an accompanying Likert-type scale were completed by 327 GPs in one FHSA area. Factor analysis of responses produced two subscales: 'perceived efficacy' and 'enthusiasm'. Reliability and validity of these were examined. RESULTS: Each subscale had good internal reliability and preliminary exploration of construct validity supported the notion that the subscales were valid. CONCLUSION: The use of this type of instrument in sampling GPs for qualitative studies could be effective for selecting subjects with a diversity of views towards the research topic. 相似文献
2.
Ronald E. McRoberts Erkki O. Tomppo Juha Heikkinen 《Remote sensing of environment》2007,111(4):466-480
The k-Nearest Neighbor (k-NN) technique has become extremely popular for a variety of forest inventory mapping and estimation applications. Much of this popularity may be attributed to the non-parametric, multivariate features of the technique, its intuitiveness, and its ease of use. When used with satellite imagery and forest inventory plot data, the technique has been shown to produce useful estimates of many forest attributes including forest/non-forest, volume, and basal area. However, variance estimators for quantifying the uncertainty of means or sums of k-NN pixel-level predictions for areas of interest (AOI) consisting of multiple pixels have not been reported. The primary objectives of the study were to derive variance estimators for AOI estimates obtained from k-NN predictions and to compare precision estimates resulting from different approaches to k-NN prediction and different interpretations of those predictions. The approaches were illustrated by estimating proportion forest area, tree volume per unit area, tree basal area per unit area, and tree density per unit area for 10-km AOIs. Estimates obtained using k-NN approaches and traditional inventory approaches were compared and found to be similar. Further, variance estimates based on different interpretations of k-NN predictions were similar. The results facilitate small area estimation and simultaneous and consistent mapping and estimation of multiple forest attributes. 相似文献
3.
A new class of detail-preserving filters for image processing 总被引:11,自引:0,他引:11
Nieminen A Heinonen P Neuvo Y 《IEEE transactions on pattern analysis and machine intelligence》1987,(1):74-90
A new class of median type filters for image processing is proposed. In the filters, linear FIR substructures are used in conjunction with the median operation. The root signals and noise attenuation properties of the FIR-median hybrid filters are analyzed and compared to representative edge preserving filtering operations. The concept of multilevel median operation is introduced to improve the detail preserving property of conventional median and the FIR-median hybrid filters. In the multilevel filters there exists a tradeoff between noise attenuation and detail preservation. The analysis and examples indicate that FIR-median hybrid filters preserve details better and are computationally much more efficient than the conventional median and the K-nearest neighbor averaging filters. 相似文献
4.
Leaf quality of the mountain birch (Betula pubescens ssp.tortuosa) for herbivores was studied at several hierarchical levels: among trees, among ramets within trees, among branches within ramets, and among short shoots within branches. The experimental units at each level were chosen randomly. The indices of leaf quality were the growth rate of the larvae of a geometrid,Epirrita autumnata, and certain biochemical traits of the leaves (total phenolics and individual phenolic compounds, total carbohydrates and individual sugars, free and protein-bound amino acids). We also discuss relationships between larval growth rate and biochemical foliage traits. Larval growth rates during two successive years correlated positively at the level of tree, the ramet, and the branch, indicating that the relationships in leaf quality remained constant between seasons both among and within trees. The distribution of variation at different hierarchical levels depended on the trait in question. In the case of larval growth rate, ramets and short shoots accounted for most of the explained variation. In the case of biochemical compounds, trees accounted for most of the variance in the content of total phenolics and individual low-molecular-weight phenolics. In the content of carbohydrates (total carbohydrates, starch, fructose, glucose, and sucrose) and amino acids, variation among branches was generally larger than variation among trees. Variation among ramets was low for most compounds. No single leaf trait played a paramount role in larval growth. Secondary compounds, represented by phenolic compounds, or primary metabolites, particularly sugars, may both be important in determining the suitability of birch leaves for larvae. If phenols are causally more important, genet-specific analyses of foliage chemistry are needed. If sugars are of primary importance, within-genet sampling and analysis of foliage chemistry are necessary. 相似文献
5.
An automated optimization procedure based on successive response surface method is presented. The method is applied to weight optimization of a stiffened plate used in marine structures. In the design space the surrogate model is spanned sequentially into an optimally restricted subspace that is converging towards at least a local optimum. Both objective function and all constraint functions are modeled using linear response surface method enabling the use of a robust and efficient simplex algorithm for the optimizations. Special attention is paid to CAD and FEM-model linking that plays a central role in practical industrial applications. In this project SOLIDWORKS and ANSYS software are adopted for structural modeling and analysis, respectively, and the optimization is carried out in a MatLab environment. The reported results achieved in this project prove the robustness and effectiveness of the proposed approach. 相似文献
6.
Marina Heinonen Katri Haila Anna-Maija Lampi Vieno Piironen 《Journal of the American Oil Chemists' Society》1997,74(9):1047-1052
The effects of low concentrations of β-carotene, α-, and γ-tocopherol were evaluated on autoxidation of 10% oil-in-water emulsions
of rapeseed oil triacylglycerols. At concentrations of 0.45, 2, and 20 μg/g, β-carotene was a prooxidant, based on the formation
of lipid hydroperoxides, hexanal, or 2-heptenal. In this emulsion, 1.5, 3, and 30 μg/g of γ-tocopherol, as well as 1.5 μg/g
of α-tocopherol, acted as antioxidants and inhibited both the formation and decomposition of lipid hydroperoxides. Moreover,
at a level of 1.5 μg/g, γ-tocopherol was more effective as an antioxidant than α-tocopherol. At levels of 0.5 μg/g, both α-
and γ-tocopherol significantly inhibited the formation of hexanal but not the formation of lipid hydroperoxides. Oxidation
was effectively retarded by combinations of 2 μg/g β-carotene and 1.5 μg/g γ- or α-tocopherol. The combination of β-carotene
and α-tocopherol was significantly better in retarding oxidation than α-tocopherol alone. While γ-tocopherol was an effective
antioxidant, a synergistic effect between β-carotene and γ-tocopherol could not be shown. The results indicate that there
is a need to protect β-carotene from oxidative destruction by employing antioxidants, such as α- and γ-tocopherol, should
β-carotene be used in fat emulsions. 相似文献
7.
Sirpa Thessler Steven Sesnie Zayra S. Ramos Bendaa Kalle Ruokolainen Erkki Tomppo Bryan Finegan 《Remote sensing of environment》2008,112(5):2485-2494
Conservation and land use planning in humid tropical lowland forests urgently need accurate remote sensing techniques to distinguish among floristically different forest types. We investigated the degree to which floristically and structurally defined Costa Rican lowland rain forest types can be accurately discriminated by a non-parametric k nearest neighbors (k-nn) classifier or linear discriminant analysis. Pixel values of Landsat Thematic Mapper (TM) image and Shuttle Radar Topography Mission (SRTM) elevation model extracted from segments or from 5 × 5 pixel windows were employed in the classifications. 104 field plots were classified into three floristic and one structural type of forest (regrowth forest). Three floristically defined forest types were formed through clustering the old-growth forest plots (n = 52) by their species specific importance values. An error assessment of the image classification was conducted via cross-validation and error matrices, and overall percent accuracy and Kappa scores were used as measures of accuracy. Image classification of the four forest types did not adequately distinguish two old-growth forest classes, so they were merged into a single forest class. The resulting three forest classes were most accurately classified by the k-nn classifier using segmented image data (overall accuracy 91%). The second best method, with respect to accuracy, was the k-nn with 5 × 5 pixel windows data (89% accuracy), followed by the canonical discriminant analysis using the 5 × 5 pixel window data (86%) and the segment data (82%). We conclude the k-nn classifier can accurately distinguish floristically and structurally different rain forest types. The classification accuracies were higher for the k-nn classifier than for the canonical discriminant analysis, but the differences in Kappa scores were not statistically significant. The segmentation did not increase classification accuracy in this study. 相似文献
8.
Self‐Sealing Porous Silicon‐Calcium Silicate Core–Shell Nanoparticles for Targeted siRNA Delivery to the Injured Brain
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9.
The European Directive on computer work (VDU 90/270/EEC) is implemented in the Finnish Government Decree. The aim of the present study was to evaluate the effects of the legislation and its applications in practice. The quantitative method used an online questionnaire. The respondents were employers (N = 934), employees (N = 1872) and occupational health care (OHC) units (N = 289). The majority of all these three groups considered the provisions clear and easy to understand, comprehensive, and easy to comply with. The provisions had a great impact on preventing mental overloading, arranging sight tests at the employer's cost, and on the refunding of eyeglasses for computer work. Most employers felt they did not need any more specific provisions, whereas half of the employees and OHC professionals would have liked the provisions to be more detailed. More explicit and specific regulations were also needed for practice applications in particular, as well as for the refunding of the costs of special eyeglasses for computer work. A total of 59% of the employers reported that costs of glasses are refunded, whereas the figure for employees was clearly lower (37%). OHC professionals reported that the costs of glasses were refunded in 82% of their customer workplaces. The practical conclusion is that employees' sight examinations and compensation for eyeglasses should be promoted in computer work. Moreover, ergonomic applications are best carried out in co-operation with OHC personnel. 相似文献
10.
Adam Kłodowski Timo Rantalainen Aki Mikkola Ari Heinonen Harri Sievänen 《Multibody System Dynamics》2011,25(4):395-409
A method for bone strain estimation is examined in this article. The flexibility of a single bone in an otherwise rigid human
skeleton model has been studied previously by various authors. However, in the previous studies, the effect of the flexibility
of multiple bones on the musculoskeletal model behavior was ignored. This study describes a simulation method that can be
used to estimate the bone strains at both tibias and femurs of a 65-year-old Caucasian male subject. The verification of the
method is performed by the comparison of the results with other studies available in literature. The results of the study
show good correlation with the results of previous empirical studies. A damping effect of the flexible bones on the model
is also studied in this paper. 相似文献