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
Dementia is a neurocognitive disorder that implies a risk factor of maltreatment by family caregivers. In this study, we analyzed both informal caregiver’s perceptions of maltreatment and aspects of the caregiver and caregiving behavior that may be associated with maltreatment. We conducted five focus groups (FGs) in three Spanish cities: Segovia, Soria and León. The themes that were identified were related to two levels of maltreatment: (a) relational and (b) institutional. At the relational level, we observed the justification of maltreatment of Older Adults with Dementia (OAswD) by family caregivers during the occurrence of behavioral symptoms. At the institutional level, we noted that lack of support from the government was considered a type of maltreatment. These themes suggest that policy issues related to healthcare should be considered. 相似文献
Recruiting and retaining direct support professionals (DSPs) remains essential to the full inclusion for persons with disabilities. Using a mixed-evaluation model, we measured DSPs' views versus those of their supervisors. DSPs expressed lower perceptions concerning their supervisors, satisfaction with their work situation, and environmental and safety factors. Focus groups provided insights into resolving issues related to compensation, work environment, and recruiting and retaining future DSPs. Motivating factors included wanting to be part of a helping community where all are valued. To improve their performance, DSPs stated their desire to understand the roles of managers and of the consumer. DSPs indicated that having career paths that provided advancement opportunities and direct contact with persons with disabilities were primary motivators. 相似文献
This paper explores systematic distortions of subjective probabilities by overconfident investors. In agreement with many non-expected utility theories, our devised setup acknowledges nonlinear weighting of physical probabilities by both rational and overconfident investors. Overconfidence – assumed to be higher after a history of gains and lower after a history of losses – changes these probability transformations. Using US asset price data, overconfident investors are found to be more optimistic than rational investors about future prospects. 相似文献
Many personal and family problems grow out of our not knowing how to process an intricate network of dualities, contradictions, dilemmas, paradoxes, and momentums that are intrinsic to the human condition rather than resulting from “disturbance” or pathology. What we have been learning in family therapy is that the processing of both “right” and “wrong” ways, or “good” and “bad” behaviors, is more likely to yield health and growth, whereas failures to process these dualities are far more the culprit of emotional disorders than bad or wrong behaviors as such. What really becomes important in family life is not the ability to stay out of trouble, but to get out of trouble, that is the ability to process conflicts and dilemmas and unfairness constructively. This way of looking at families helps us to account for and integrate many of the hard empirical findings that have been gathering now for twenty years in family therapy.相似文献
The present article draws attention to ways in which the goodness of fit between social services and their clients, both in the present and the past, determines the extent to which services are successful–in the sense that clients experience them as helpful and as furthering their well-being, and that there is objective evidence of improvement in their situation.
To provide an initial conceptual framework for exploration in this area, a number of terms are introduced and defined. These include ‘inapt service”, ‘inaptly served families’, and ‘good enough services’.
It is contended that biases that promote inaptness, in the areas of policy, organization, practice, and research and evaluation, have contributed to the proliferation and perpetuation of inapt services. As a basis for further reflection and for efforts to transform ‘inapt’ service systems into ones that are ‘good enough’, twelve such biases are discussed.
Finally, premises and directions for action that promote such transformative efforts are suggested. 相似文献