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711.
Abstract A recent wave of research promotes the idea that anonymity or deindividuation precipitates collective behavior. Specifically, anonymous individuals are more likely to participate in collective behavior events than people among friends and acquaintances. To reconsider this recent resurgence of a more contemporary contagion theory, we replicate and expand upon Aveni's (1977) study of crowd behavior. Our survey data of crowd and collective behavior participants show that anonymity actually hinders the emergence of collective behavior. Rather, collective behavior participants are more likely to be in small groups rather than isolated individuals. Our data do suggest that one form of anonymity (i.e., anonymity from formal agents of social control) can facilitate the emergence of collective behavior. 相似文献
712.
713.
Sample size re-estimation without unblinding for normally distributed outcomes with unknown variance
Monitoring clinical trials in nonfatal diseases where ethical considerations do not dictate early termination upon demonstration of efficacy often requires examining the interim findings to assure that the protocol-specified sample size will provide sufficient power against the null hypothesis when the alternative hypothesis is true. The sample size may be increased, if necessary to assure adequate power. This paper presents a new method for carrying out such interim power evaluations for observations from normal distributions without unblinding the treatment assignments or discernably affecting the Type 1 error rate. Simulation studies confirm the expected performance of the method. 相似文献
714.
715.
John Rudnik Taylor R. Patskanick Julie B. Miller Lisa D’Ambrosio Joseph F. Coughlin 《Journal of gerontological social work》2020,63(5):392-411
ABSTRACT The past twenty years have seen a surge of resources for and public attention devoted to civic participation opportunities for older adults in the United States. At the same time, technology has transformed the way information related to political and social issues is spread and shared. As more older adults migrate to using a wider range of communication tools and the internet, technology-mediated forms of engagement represent a new way for the oldest old to participate in society. In this study, a panel of adults ages 85 and older was surveyed to understand their experiences engaging with political and social issues. Responses to a questionnaire (N = 24) and focus groups (n = 22) indicate the oldest old are interested in social and political issues, and there are opportunities for technology to facilitate the oldest olds’ civic and political action. This study identifies roles social workers may play in helping the oldest old engage with social and political issues in their communities. 相似文献
716.
Jini L. Roby Missy Jean Lambert Joseph Lambert 《International Journal of Social Welfare》2009,18(4):342-353
Although education of children is universally accepted as a leading mechanism of poverty eradication and social development, many developing nations continue to struggle in achieving gender parity in primary and secondary education. While Mozambique has recently accelerated its efforts to reduce this gap, girls are still enrolled and attending school at a much lower rate than boys. The present study explored the barriers to children's – especially girls' – education in central Mozambique, based on information on 738 children in two separate communities. Household, child, environmental, and social/cultural factors are examined in the context of global and regional data. The study found girls to be impacted more negatively by every correlating factor, including the lingering practice, in rural areas, of early marriage. Policy and research implications are discussed. 相似文献
717.
The condition of the used items acquired by remanufacturers is often highly variable, and sorting is an important aspect of remanufacturing operations. Sorting policies—the rules specifying which used products should be remanufactured and which should be scrapped—have received limited attention in the literature. In this paper, we examine the case of a remanufacturer who acquires unsorted used products as needed from third party brokers. As more used items are acquired for a given demand, the remanufacturer can be more selective when sorting. Thus, two related decisions are made: how many used items to acquire, and how selective to be during the sorting process. We derive optimal acquisition and sorting policies in the presence of used product condition variability for a remanufacturer facing both deterministic and uncertain demand. We show the existence of a single optimal acquisition and sorting policy with a simple structure and show that this policy is independent of production amount when acquisition costs are linear. 相似文献
718.
Yigal Bejerano Joseph Naor Alexander Sprintson 《Journal of Combinatorial Optimization》2006,12(1-2):17-34
We study efficient algorithms for establishing reliable connections with bandwidth guarantees in communication networks. In
the normal mode of operation, each connection uses a primary path to deliver packets from the source to the destination. To ensure continuous operation in the event of an edge failure,
each connection uses a set of backup bridges, each bridge protecting a portion of the primary path. To meet the bandwidth requirement of the connection, a certain amount
of bandwidth must be allocated the edges of the primary path, as well as on the backup edges. In this paper, we focus on minimizing
the amount of required backup allocation by sharing backup bandwidth among different connections. We consider efficient sharing schemes that require only partial information about the current state of the network. Specifically, the only information available for each edge is the total
amount of primary allocation and the cost of allocating backup bandwidth on this edge. We consider the problem of finding
a minimum cost backup allocation together with a set of bridges for a given primary path. We prove that this problem is
NP-hard and present an approximation algorithm whose performance is within
of the optimum, where n is the number of edges in the primary path. We also consider the problem of finding both a primary path and backup allocation
of minimal total cost.
A preliminary version of this paper appears in the Proceedings of 13th Annual European Symposium on Algorithms - ESA 2005,
Mallorca, Spain.
J. (Seffi) Naor: This research is supported in part by a foundational and strategical research grant from the Israeli Ministry
of Science, and by a US-Israel BSF Grant 2002276. 相似文献
719.
We consider the estimation of Poisson regression models in which structural variation in a subset of the parameters is permitted. It is noted that coventional estimation algorithms are likely to impose restrictions on the number of explanatory variables and the number of structural regimes. We propose an alternative algorithm that implements partitioned matrix inversion and thereby avoids restictions on the size of the model. The algorithm is applied to a model of shopping behavior Adjustments in the algorithm necessary for dealing with censored data are detailed. 相似文献
720.