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321.
We investigate how choices for uncertain gain and loss prospects are affected by the decision maker’s perceived level of knowledge about the underlying domain of uncertainty. Specifically, we test whether Heath and Tversky’s (J Risk Uncertain 4:5–28, 1991) competence hypothesis extends from gains to losses. We predict that the commonly-observed preference for high knowledge over low knowledge prospects for gains reverses for losses. We employ an empirical setup in which participants make hypothetical choices between gain or loss prospects in which the outcome depends on whether a high or low knowledge event occurs. We infer decision weighting functions for high and low knowledge events from choices using a representative agent preference model. For gains, we replicate the results of Kilka and Weber (Manage Sci 47:1712–1726, 2001), finding that decision makers are more attracted to choices that they feel more knowledgeable about. However, for losses, we find limited support for our extension of the competence effect.  相似文献   
322.
The health risk and the nutritional benefit of a food are usually assessed separately. Toxicologists recommend limiting the consumption of certain fish because of methylmercury; while nutritionists recommend eating more oily fish because of omega 3. A common evaluation is imperative to provide coherent recommendations. In order to evaluate the risks along with the benefits related to fish consumption, a common metric based on the quality-adjusted life year (QALY) method has been used. The impact of a theoretical change from a medium n-3 PUFAs intake to a high intake is studied, in terms of the cardiovascular system (CHD mortality, stroke mortality and morbidity) and on fetal neuronal development (IQ loss or gain). This application can be considered as a sensitive analysis of the model used and looks at the impact of changing the dose-response relationships between cardiovascular diseases and n-3 PUFAs intakes. Results show that increasing fish consumption may have a beneficial impact on health. However, the confidence interval of the overall estimation has a negative lower bound, which means that this increase in fish consumption may have a negative impact due to MeHg contamination. Some limits of the QALY approach are identified. The first concerns determination of the dose-response relationships. The second concerns the economic origins of the approach and of individual preferences. Finally, since only one beneficial aspect and one risk element were studied, consideration should be given to how other beneficial and risk components may be integrated in the model.  相似文献   
323.
We deal with the ranking problem of the nodes in a directed graph. The bilateral relationships specified by a directed graph may reflect the outcomes of a sport competition, the mutual reference structure between websites, or a group preference structure over alternatives. We introduce a class of scoring methods for directed graphs, indexed by a single nonnegative parameter α. This parameter reflects the internal slackening of a node within an underlying iterative process. The class of so-called internal slackening scoring methods, denoted by λ α , consists of the limits of these processes. It is seen that λ0 extends the invariant scoring method, while λ extends the fair bets scoring method. Method λ1 corresponds with the existing λ-scoring method of Borm et al. (Ann Oper Res 109(1):61–75, 2002) and can be seen as a compromise between λ0 and λ . In particular, an explicit proportionality relation between λ α and λ1 is derived. Moreover, the internal slackening scoring methods are applied to the setting of social choice situations where they give rise to a class of social choice correspondences that refine both the Top cycle correspondence and the Uncovered set correspondence.  相似文献   
324.
The objective of this article is to understand coordination as it unfolds in case management practices in the context of integrated care networks devoted to frail elderly individuals. More specifically, my goal is to describe practical coordination processes. I conducted a qualitative exploratory study using an embedded case study design. My research covers three Health and Social Services Centres in Québec. I observed that case management is more frequently justified by a situation in which home care is precarious than by the intensity and multidimensionality present in a situation. In such instances, case management intervenes through a standby mode.  相似文献   
325.
The article presents a case study of an outpatient mental health clinic serving Latino older adults. The study explored staff perceptions on the clinic development and the context within an immigrant multicultural community. The study used in-depth, semistructured interviews with support staff, clinical social workers, and administrators. Interviews were analyzed using a thematic content analysis. The mental health clinic formation was perceived by staff as an ecological process stemming from the needs of the Latino immigrant senior clients. A close knit and interdependent culture allowed the clinic to adjust to diversity and changing cultural contexts.  相似文献   
326.
The article explores differences in the assessment and decision‐making processes, in child welfare services where a standardized template is implemented and in services where it is not. Child welfare services in several countries use different approaches to assess children's and families' need for intervention. In Norway, as in other European countries, there is a shortage of knowledge about decision‐making strategies. The article examines how 36 child welfare caseworkers in 6 different teams in Norway investigate, assess, and make decisions at the phase of an incoming referral. The analysed data were collected by focus group interviews. We use decision theory as a theoretical frame of reference. The analysis shows variation in the assessment procedure at different points of the process, depending on which approach was used. Despite such differences, the final decisions made were almost identical. Even though the data has its limitations because of the small number of informants, the results indicate that choice of approach is not decisive for decision‐making in the child welfare services.  相似文献   
327.
This paper focuses on the development of a new extension of the generalized skew-normal distribution introduced in Gómez et al. [Generalized skew-normal models: properties and inference. Statistics. 2006;40(6):495–505]. To produce the generalization a new parameter is introduced, the signal of which has the flexibility of yielding unimodal as well as bimodal distributions. We study its properties, derive a stochastic representation and state some expressions that facilitate moments derivation. Maximum likelihood is implemented via the EM algorithm which is based on the stochastic representation derived. We show that the Fisher information matrix is singular and discuss ways of getting round this problem. An illustration using real data reveals that the model can capture well special data features such as bimodality and asymmetry.  相似文献   
328.
Artificial neural networks have been successfully applied to a variety of machine learning tasks, including image recognition, semantic segmentation, and machine translation. However, few studies fully investigated ensembles of artificial neural networks. In this work, we investigated multiple widely used ensemble methods, including unweighted averaging, majority voting, the Bayes Optimal Classifier, and the (discrete) Super Learner, for image recognition tasks, with deep neural networks as candidate algorithms. We designed several experiments, with the candidate algorithms being the same network structure with different model checkpoints within a single training process, networks with same structure but trained multiple times stochastically, and networks with different structure. In addition, we further studied the overconfidence phenomenon of the neural networks, as well as its impact on the ensemble methods. Across all of our experiments, the Super Learner achieved best performance among all the ensemble methods in this study.  相似文献   
329.
A new family of slash distributions, the modified slashed-Rayleigh distribution, is proposed and studied. This family is an extension of the ordinary Rayleigh distribution, being more flexible in terms of distributional kurtosis. It arises as a quotient of two independent random variables, one being a Rayleigh distribution in the numerator and the other a power of the exponential distribution in denominator. We present properties of the proposed family. In addition, we carry out estimation of the model parameters by moment and maximum likelihood methods. Finally, we conduct a small-scale simulation study to evaluate the performance of the maximum likelihood estimators and apply the results to a real data set, revealing its good performance.  相似文献   
330.
William James's Varieties of Religious Experience is a classic psycho‐philosophical study of the experience of the sacred and of its practical effects on the ordinary life of extraordinary persons. In a pragmatic variation of Kant's proof of god's existence, James uses personal accounts of converts to empirically demonstrate that there's “something” that has causal effects on the well‐being of the person. While the article is largely sympathetic to James explorations of the mystical, it offers a sociological variation on the Varieties that foregrounds the social, cultural and political aspects of religion.  相似文献   
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