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21.
Frank AW 《Second opinion (Park Ridge, Ill.)》1994,20(1):10-18
In attempting to manage their practices efficiently, doctors may not allow seriously ill patients enough time to sort out their feelings and raise important questions. What is at stake here is not information about prognosis and treatments but the very survival of the soul. 相似文献
22.
Evolution strategies (ESs) are a special class of probabilistic, direct, global optimization methods. They are similar to genetic algorithms but work in continuous spaces and have the additional capability of self-adapting their major strategy parameters. This paper presents the most important features of ESs, namely their self-adaptation, as well as their robustness and potential for parallelization which they share with other evolutionary algorithms.Besides the early (1 + 1)-ES and its underlying theoretical results, the modern ( + )-ES and (, )-ES are presented with special emphasis on the self-adaptation of strategy parameters, a mechanism which enables the algorithm to evolve not only the object variables but also the characteristics of the probability distributions of normally distributed mutations. The self-adaptation property of the algorithm is also illustrated by an experimental example.The robustness of ESs is demonstrated for noisy fitness evaluations and by its application to discrete optimization problems, namely the travelling salesman problem (TSP).Finally, the paper concludes by summarizing existing work and general possibilities regarding the parallelization of evolution strategies and evolutionary algorithms in general. 相似文献
23.
This paper deals with techniques for obtaining random point samples from spatial databases. We seek random points from a continuous domain (usually 2) which satisfy a spatial predicate that is represented in the database as a collection of polygons. Several applications of spatial sampling (e.g. environmental monitoring, agronomy, forestry, etc) are described. Sampling problems are characterized in terms of two key parameters: coverage (selectivity), and expected stabbing number (overlap). We discuss two fundamental approaches to sampling with spatial predicates, depending on whether we sample first or evaluate the predicate first. The approaches are described in the context of both quadtrees and R-trees, detailing the sample first, acceptance/rejection tree, and partial area tree algorithms. A sequential algorithm, the one-pass spatial reservoir algorithm is also described. The relative performance of the various sampling algorithms is compared and choice of preferred algorithms is suggested. We conclude with a short discussion of possible extensions. 相似文献
24.
Increasing attention is being given to the possible consequences which might follow from the exhaustion of the world's natural resources. Countering the pessimistic conclusions of such institutions as the Club of Rome, economists such as Wilfred Beckerman have emphasized the importance of substitution, pointing to many examples where a shortage of one raw material has led to the discovery or development of alternative materials, e.g. artificial for natural rubber, aluminium for copper.Substitution usually occurs through normal market mechanisms, i.e. changes in relative prices. However in some circumstances the market mechanism may be inhibited by a variety of factors, so that its operation requires to be supplemented by an outside agency. This article explores this possibility in relation to the paper making industry, which provides a particularly interesting example owing to the existence of a well established market in waste paper, the main substitute for the major natural resource, woodpulp.A brief indication is given of the relative importance of waste paper and an outline of the structure of the U.K. market; the conditions under which greater utilization of waste paper might occur are then considered taking a sideways look at the influence of the individual. In the final section the various implications for the role of the state are summarized. 相似文献
25.
Relationships are examined between feelings of political competenceand cumulative media usage in five Western nations. Wide differentiationamong the nations studied is found, suggesting that multivariateanalysis is needed to establish whether media usage makes aunique contribution to feelings of political competence, oracts as a surrogate for other background variables. 相似文献
26.
GM Foods and the Misperception of Risk Perception 总被引:3,自引:0,他引:3
George Gaskell Nick Allum Wolfgang Wagner Nicole Kronberger Helge Torgersen Juergen Hampel Julie Bardes 《Risk analysis》2004,24(1):185-194
Public opposition to genetically modified (GM) food and crops is widely interpreted as the result of the public's misperception of the risks. With scientific assessment pointing to no unique risks from GM crops and foods, a strategy of accurate risk communication from trusted sources has been advocated. This is based on the assumption that the benefits of GM crops and foods are self-evident. Informed by the interpretation of some qualitative interviews with lay people, we use data from the Eurobarometer survey on biotechnology to explore the hypothesis that it is not so much the perception of risks as the absence of benefits that is the basis of the widespread rejection of GM foods and crops by the European public. Some respondents perceive both risks and benefits, and may be trading off these attributes along the lines of a rational choice model. However, for others, one attribute-benefit-appears to dominate their judgments: the lexicographic heuristic. For these respondents, their perception of risk is of limited importance in the formation of attitudes toward GM food and crops. The implication is that the absence of perceived benefits from GM foods and crops calls into question the relevance of risk communication strategies for bringing about change in public opinion. 相似文献
27.
McEvoy A Spirgen N 《Journal of gambling studies / co-sponsored by the National Council on Problem Gambling and Institute for the Study of Gambling and Commercial Gaming》2012,28(1):69-76
There is an absence of research on gambling among prison inmates during their incarceration. Little is known about how prisoners
organize gambling activities or the potential risks they face from gambling. Similarly, no empirical attention has been given
to how correctional institutions respond to inmate gambling. This study employed interviews with 55 male prisoners and self-administered
surveys with 159 correctional officers and staff, at two medium security prisons in Ohio. Data were gathered on prevalence
and patterns of inmate gambling, perceived hazards of gambling, and perceived institutional responses to prisoner gambling.
Findings suggest that inmate gambling is common and constitutes an important feature of the underground economy of prisons,
yet little is done to deter or prevent this activity. Suggestions are made for more effective institutional responses. 相似文献
28.
Welfare state studies are usually motivated by one or both of two concerns: programme effects on the incidence of poverty, and the possibility of perverse incentive effects. Most research has been comparative, using cross‐national indicators from the Organisation for Economic Co‐operation and Development and other international organizations. That research often contrasts the generosity of programmes in a number of European countries and the lack of it in the USA. Focusing on income transfers after job‐loss, in this article we critically examine the comparative evidence on US welfare state generosity and then use the Panel Study of Income Dynamics (PSID) to estimate what happens to job‐losers' incomes. The comparative analysis suggests conclusions more nuanced than found in much of the literature. The PSID analysis shows how the income effects of job‐loss vary across job‐losers and suggests that the role of unemployment compensation programmes in supporting incomes may be overstated. 相似文献
29.
Frank Tuyl 《The American statistician》2019,73(2):151-158
In the context of an objective Bayesian approach to the multinomial model, Dirichlet(a, …, a) priors with a < 1 have previously been shown to be inadequate in the presence of zero counts, suggesting that the uniform prior (a = 1) is the preferred candidate. In the presence of many zero counts, however, this prior may not be satisfactory either. A model selection approach is proposed, allowing for the possibility of zero parameters corresponding to zero count categories. This approach results in a posterior mixture of Dirichlet distributions and marginal mixtures of beta distributions, which seem to avoid the problems that potentially result from the various proposed Dirichlet priors, in particular in the context of extreme data with zero counts. 相似文献
30.
Nicole Dubus 《Social Work Education》2014,33(2):254-270
This paper describes a pilot project to develop an effective applied learning experience for graduate social work students. An asset-based social justice model was used as a guide in the development of the project. Importance was placed on the host community determining its own needs and the contributions the students would provide. A partnership with community stakeholders was developed. The stakeholders decided the needs to be addressed and the faculty prepared the students to meet those needs. Successes and limitations of the pilot project are reviewed. 相似文献