排序方式: 共有30条查询结果,搜索用时 15 毫秒
21.
Many real-world social networks are hypergraphs because they either explicitly support membership in groups or implicitly include communities. We present the HyperBC algorithm that exactly computes betweenness centrality (or BC) in hypergraphs. The forward phase of HyperBC and the backpropagation phase are specifically tailored for BC computation on hypergraphs. In addition, we present an efficient method for pruning networks through the notion of “non-bridging” vertices. We experimentally evaluate our algorithm on a variety of real and artificial networks and show that it significantly speeds up the computation of BC on both real and artificial hypergraphs, while at the same time, being very memory efficient. 相似文献
22.
This paper is devoted to the problem of estimating the square of population mean (μ2) in normal distribution when a prior estimate or guessed value σ0
2 of the population variance σ2 is available. We have suggested a family of shrinkage estimators , say, for μ2 with its mean squared error formula. A condition is obtained in which the suggested estimator is more efficient than Srivastava et al’s (1980) estimator Tmin. Numerical illustrations have been carried out to demonstrate the merits of the constructed estimator over Tmin. It is observed that some of these estimators offer improvements over Tmin particularly when the population is heterogeneous and σ2 is in the vicinity of σ0
2. 相似文献
23.
The impacts of fish consumption advisories on recreational and subsistence fishing, particularly in fresh waters, have been examined extensively. By contrast, little attention has focused on organized recreational fishing, such as from party and charter boats, and particularly for salt water fish. We interviewed 93 New Jersey boat captains to determine their knowledge about fish consumption advisories, and whether, in their opinion, clients knew of fish consumption advisories, and whether they thought advisories had an effect on recreational fishing and their businesses. Advisories were ranked by captains as a moderate influence on the success of their business, less so than number of fish caught, strength of the economy, overfishing by commercial boats, and management regulations. Only one boat captain had not heard warnings about eating fish, but what captains said they had heard was mixed in its accuracy and completeness. Clients expect captains to know about fish, and about half of boat captains said clients had asked about the safety of eating fish. Captains who felt advisories were affecting their businesses tended to fish for species without high levels of mercury (except for bluefish) or PCBs, the primary contaminants of concern for state advisories and federal advice. However, these captains worked closer to areas (e.g., Raritan Bay complex and New York Harbor) subject to advisories than did other captains, and were more prone to say that management regulations (e.g., fish size, creel limits, seasons) and marketing and advertising by the industry or state were strong influences on the success of their seasons. Comparing captains who thought advisories had some or great effect (60%) versus those reporting "no effect" (40%), there was no difference in the mean percentage of trips targeting high mercury species such as swordfish and shark. Many captains said they would or might post advisories, but 42% of the boat captains said they would not post consumption warnings if the state provided them. The significant portion (at least 15%) of saltwater fishing supported by these businesses suggests that these captains are an important conduit for future risk communication. 相似文献
24.
Ramesh K. Shukla 《决策科学》1982,13(3):450-470
The relative influence of four power bases was investigated in four decision-making contexts using data from forty successfully implemented decisions. The analysis suggests that position power decreases in influence while resource power and political power increase in influence as decision contexts vary from less to more uncertainty. Expert power derives its influence when organizational uncertainty is low and when technical uncertainty is reduced, whereas political power thrives when organizational uncertainty is high and when technical uncertainty remains high. Indexing the influence of power bases provides greater understanding of decision processes than the sociological or social-psychological approaches of studying participation. 相似文献
25.
Abstract : There is good evidence that shift work has negative effects on workers health, safety and performance. It is quite appropriate that attention is paid to this very important feature of socio-technical systems, which may adversely affect mental and physical health, social life and safety of shift workers. Research into the impact of shift work on professionals has consistently identified a range of negative outcomes in physical, psychological, and social domains (Akerstedt, 1988; Costa, Lievore, Casaletti, Gaffuri, & Folkard, 1989; Kogi, 2005; Paley & Tepas, 1994). Hospitals, the biggest employer in the health care field, employ more night shift workers than any other industry. It can therefore be inferred that in medical domain high percentage of workforce may be affected by problems related to shift work. Thus the present study will provide knowledge base for the problems faced by the female nurses. The present study was undertaken with an objective of getting an insight into the problems faced by female nurses in shift work. . It was found that the female nurses in India worked on roaster pattern of change in shift every seven days. They did not have a say in the change of duties, it could only be done on mutual grounds. Partners of younger group did not much adjust to their shift pattern this created stress among the nurses.The results showed that the female nurses in both the age groups i.e. 30-45 years and 45-60 years faced many problems related to health and well being, fatigue, social and domestic situations. They could not give much time to their children in particular. Travelling in nights was risky for them. Common problem was the insufficient sleep during night shifts. The nurses had to cater to the needs of the family, children in particular along with the adjustments to be made due to shift work. They had to sometimes do the night duties and attend social functions as a part of their duty. Children and husband in some cases did not cooperate this lead to frustration. When asked as to whether they would could shift job if they get regular one more than 50 % said yes this means that there need to be come training and intervention for the shift workers and their family so that the problems faced and their impact on personal health of the female nurses could be reduced. 相似文献
26.
AbstractThe paper elicits subjectively the Dirichlet prior hyperparameters based on the realistic opinion collected from the experts. The procedure used for subjective elicitation considers several stages such as the choice of experts, formation of some relevant questions to be asked to the experts for getting their opinion, pooling of opinion, quantification of information and then the formation of exact prior distribution through quantile assessment based on an iterative procedure. The resulting prior distribution is used to provide the Bayes analysis assuming multinomial sampling plan. The results are illustrated by means of a data set involving two life style factors of gallbladder carcinoma patients. The results convey the message that matches closely with the opinion given by the medical experts. 相似文献
27.
Additive Manufacturing (AM) technology presents a very optimistic case for its application for mass customisation. Even though theoretically suitable, practically several critical barriers inhibit its implementation. Thus, this paper attempts to identify those barriers and also understand the dynamic interaction among them. The barriers were identified by a detailed literature review and validated by expert opinions. Interpretative Structural Modelling (ISM) was applied to determine the mutual influences among the barriers. It was also able to ascertain the level of the barriers and categorise them based on their driving power and dependence. The results are highly useful for industry practitioners to determine the interventions required to overcome the most dominant barriers. 相似文献
28.
Joanna Burger Christian Jeitner Heather Jensen Megan Fitzgerald Stacey Carlucci Sheila Shukla Sean Burke Robert Ramos Michael Gochfeld 《Urban Ecosystems》2004,7(1):17-27
The habitat use of basking northern water (Nerodia sipedon) and Eastern garter (Thamnophis sirtalis) snakes was examined along the Raritan Canal, an urbanized area of central New Jersey. There were significant differences between the two species with respect to cloud cover, canopy cover, and the distance to the path and the water, but not with respect to percent of the body exposed to the sun, and percent of the snake that was visible. Water snakes were more likely to bask on bushes, branches and logs than were garter snakes. Garter snakes basked when both the air and water temperature were lower than did water snakes. The lack of basking sites in the water suggests that those along shore are important, including the low hanging branches used by the watersnakes. 相似文献
29.
AbstractThis paper aims to address the constraints faced in incorporating smallholders in sustainable palm oil production. There exists literature that acknowledges the need for incorporating smallholders in the production of sustainable palm oil but none has proposed a solution beyond ‘Roundtable on Sustainable Palm Oil’ (RSPO) certification. In the current business scenario, several organizations are struggling to procure RSPO certified palm oil even after committing huge resources. RSPO, though a good first step, has a major process and capacity constraints resulting in long processing times, delays, and lack of traceability for the customers. This paper proposes a Big Data Analytics framework enabled by cutting-edge technologies to incorporate smallholders in the RSPO certification process. The data used was collected through farm visits, stakeholder meetings, key stakeholder interviews, and, secondary sources. The proposed framework not only addresses the limitation of the current certification process but also converts it from being punitive to preventive. The outcomes of this research will be extremely useful for all the stakeholders in the palm oil supply chain. 相似文献
30.
A significant majority of hazardous materials (hazmat) shipments are moved via the highway and railroad networks, wherein the latter mode is generally preferred for long distances. Although the characteristics of highway transportation make trucks the most dominant surface transportation mode, should it be preferred for hazmat whose accidental release can cause catastrophic consequences? We answer this question by first developing a novel and comprehensive assessment methodology—which incorporates the sequence of events leading to hazmat release from the derailed railcars and the resulting consequence—to measure rail transport risk, and second making use of the proposed assessment methodology to analyze hazmat transport risk resulting from meeting the demand for chlorine and ammonia in six distinct corridors in North America. We demonstrate that rail transport will reduce risk, irrespective of the risk measure and the transport corridor, and that every attempt must be made to use railroads to transport these shipments. 相似文献