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71.
In this paper we present and discuss several optimisation problems that arise in the management of data flow in wireless sensor networks (WSNets). We consider a hierarchical architecture for WSNets composed of sensors, relays, and relay gateways. Sensors send data they generate at a known average bit rate to relays in one hop. The relay nodes use a multi-hop mechanism to reach a set of assigned gateways which then forward the data directly to the base station. We are concerned with finding an assignment of relay gateways to relays so that certain constraints are satisfied. We define a unified model in which constraints such as lifetime, data delay, and data flow splitting are formulated in terms of four optimisation problem in graphs.  相似文献   
72.
Empirical research on strategic alliances has been limited because previous studies examined alliance outcomes, and the factors associated with them, from a single partner in a manufacturing alliance. Furthermore, many of these studies have been done from a transaction cost perspective and researchers have inferred opportunistic behavior, rather than directly measuring it and observing its actual relationship with alliance performance. Building on previous transaction cost theory and research, this study seeks to address these gaps by analyzing factors associated with both opportunistic behavior and alliance performance within a major service sector, namely the US healthcare industry. After controlling for asset specificity and alliance age, we found that partner trustworthiness and contractual safeguards were negatively related to opportunistic behavior. Furthermore, opportunistic behavior was negatively related to alliance performance, as hypothesized. Interestingly, mutual equity investments were found to be unrelated to opportunistic behavior, counter to transaction‐cost logic. These findings refine and extend the transaction‐cost economics perspective regarding our understanding of strategic alliance behavior and outcomes, and offer executives in service‐based industries some practical ideas for assuring favorable strategic alliance outcomes.  相似文献   
73.
精明的商业领袖会在冲突中寻找创造价值的时机无论在哪一行,总会有争吵。未按时交货;客户改变主意;合作伙伴不遵守承诺;部门的主管不批准某项预算而且还进行人身攻击。经理们对待这样的冲突和对待其他生意的方式往往是不同的。他们的做法完全不同,就好像解决冲突需要完全不同的方式:要不你获胜,要不我获胜。双  相似文献   
74.
Social loafing was investigated by testing a multilevel model among 23 intact work groups comprised of 168 employees representing two organizations. Results demonstrated that as hypothesized at the individual level, increases in task interdependence and decreases in task visibility and distributive justice were associated with greater occurrence of social loafing. At the group level, increased group size and decreased cohesiveness were related to increased levels of social loafing. Of particular interest was the finding that group member perceptions of perceived coworker loafing was associated with reduced social loafing, opposite of our predictions. We suggested that this unexpected finding may provide evidence of a social compensation effect.  相似文献   
75.
This study examined nonviolent (NV), unilaterally violent (UV), and mutually violent (MV) patterns of perpetrated intimate partner violence in relation to dyadic relationship quality and partner injury. The respondents were 1,294 young adult, Add Health partners (AHP) and their non-Add Health partners (NAHP), in dating, engaged, or in marital relationships, who were participants in Wave III of the National Longitudinal Study of Adolescent Health (Add Health). Using both partner reports of perpetration to classify intimate partner violence (IPV) patterns resulted in 25% of couples with a MV pattern, and 75% of couples with a UV pattern; among those couples (41%) reporting any perpetrated IPV. Results also showed poorer relationship quality and higher partner sensation-seeking scores among MV and UV couples when contrasted with NV couples. Those couples with MV patterns were more likely to contain partner injury than those with UV patterns.  相似文献   
76.
The present interdisciplinary study explored whether perceived loneliness is associated with ventromedial prefrontal cortex (vMPFC) activation during self‐ and social judgments (friends and teachers) in adolescents. Moreover, we examined how vMPFC activity is related to the academic self‐concept (ASC). Results of manifest path analysis indicated that high perceived loneliness was related to lower neural response to self‐judgments. In turn, high neural response to self‐judgments was positively associated with the ASC, whereas there was a trendwise negative association between high neural response to teacher‐related judgments and ASC. This study reveals associations between perceived loneliness and neural processing of the self, underlining the idea that feeling isolated from others may hinder self‐insight and, by extension, the formation of a stable academic self‐concept.  相似文献   
77.
78.
Insight into measures of peakedness, heavy-tailedness, and kurtosis can be gained by studying Ruppert’s ratios of interquantile ranges. They are not only monotone in Horn’s measure of peakedness when applied to the central portion of the population, but also monotone in the practical tail-index of Morgenthaler and Tukey, when applied to the tails. Non-parametric confidence intervals are found for Ruppert’s ratios, and sample sizes required to obtain such intervals for a pre-specified relative width and level are provided. In addition, the empirical power of distribution-free tests for peakedness and bimodality are found for some symmetric distributions.  相似文献   
79.
Near-miss outcomes during gambling are non-win outcomes that fall close to a pay-out. While objectively equivalent to an outright miss, near-misses motivate ongoing play and may therefore be implicated in the development of disordered gambling. Given naturalistic data showing increases in heart rate (HR) and electrodermal activity (EDA) during periods of real gambling play, we sought to explore the phasic impact of win, near-miss and full-miss outcomes on physiological arousal in a controlled laboratory environment. EDA and HR were monitored as healthy, student participants (n = 33) played a simulated slot-machine task involving unpredictable monetary wins. A second gambling distortion, perceived personal control, was manipulated within the same task by allowing the participant to select the play icon on some trials, and having the computer automatically select the play icon on other trials. Near-misses were rated as less pleasant than full-misses. However, on trials that involved personal choice, near-misses produced higher ratings of ‘continue to play’ than full-misses. Winning outcomes were associated with phasic EDA responses that did not vary with personal choice. Compared to full-misses, near-miss outcomes also elicited an EDA increase, which was greater on personal choice trials. Near-misses were also associated with greater HR acceleration than other outcomes. Near-miss outcomes are capable of eliciting phasic changes in physiological arousal consistent with a state of subjective excitement, despite their objective non-win status.  相似文献   
80.
Andres RO  Wade C 《Work (Reading, Mass.)》2012,41(Z1):3367-3371
This is a review of walking tasks in the railroad environment, and the injuries that result from slips, trips, falls, or other acute or even non-traumatic exposures. The lack of federal regulations for railroad walkways has led several states to develop and enforce their own regulations. Support from the research literature for such regulations has come from biomechanical studies of the effects of walking on railroad ballast, which will be reviewed.  相似文献   
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