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51.
高海洲 《黄石理工学院学报》2011,27(5):1-5
物理层数据传输方案的选择是认知无线电(CR)技术能在实际中广泛应用的重要基础。给出了将SC—FDMA(单载波频分多址)技术应用于CR网络中的传输方案,并与传统的NC—OFDM(非连续的OFDM)技术进行分析比较。仿真结果和相应分析表明:在CR网络中,总体而言SC—FDMA的性能比NC—OFDM更为优良,特别是在严重的频率选择性衰落环境中,或者是当认知用户的可用频谱资源(子载波)比较稀少时,SC—FDMA的性能优势更加明显。因此SC—FDMA是一种很有前景的技术,在不久的将来有希望取代NC—OFDM,成为CR网络的物理层传输方案。 相似文献
52.
基于案例推理的非常规突发事件资源需求预测 总被引:2,自引:0,他引:2
近年来非常规突发事件频繁发生,严重危害了人民的生命财产安全,而如何及时预测灾害发生后的资源需求成为一个重要课题。文章提出了一种精确的预测方法,将模糊集理论,神经网络Hebb学习规则和多元线性回归与案例推理法相结合。这种方法很好地解决了非常规突发事件资源需求预测这类信息不完备、不精确问题,能够比较准确的作出资源的需求预测。该模型对灾害资源需求预测具有一定的参考价值。 相似文献
53.
Vincent Cassar Rob B. Briner Sandra Buttigieg 《International Journal of Human Resource Management》2016,27(5):567-592
While the literature has suggested the possibility of breach being composed of multiple facets, no previous study has investigated this possibility empirically. This study examined the factor structure of typical component forms in order to develop a multiple component form measure of breach. Two studies were conducted. In study 1 (N = 420) multi-item measures based on causal indicators representing promissory obligations were developed for the five potential component forms (delay, magnitude, type/form, inequity and reciprocal imbalance). Exploratory factor analysis showed that the five components loaded onto one higher order factor, namely psychological contract breach suggesting that breach is composed of different aspects rather than types of breach. Confirmatory factor analysis provided further evidence for the proposed model. In addition, the model achieved high construct reliability and showed good construct, convergent, discriminant and predictive validity. Study 2 data (N = 189), used to validate study 1 results, compared the multiple-component measure with an established multiple item measure of breach (rather than a single item as in study 1) and also tested for discriminant validity with an established multiple item measure of violation. Findings replicated those in study 1. The findings have important implications for considering alternative, more comprehensive and elaborate ways of assessing breach. 相似文献
54.
针对突发事件下的应急物资调运问题,考虑了多个地区同时受灾以及多个出救点需要对其进行救灾并且各出救点的运力有限的情况,以最小化总的车辆运输费用,最大化救灾效率、各受灾点的救灾满意度,以及各受灾点得到救助的公平性为目标,建立了该问题的多目标混合整数非线性规划模型,并提出了一个基于两层架构协调的迭代式遗传算法进行求解。基于仿真数据的实验结果证明了所提出的模型和算法的有效性。 相似文献
55.
Chan Lee Hyuneung Lee Jongsun Park 《International Journal of Human Resource Management》2013,24(20):2837-2857
This study suggests an integrative transfer of training model and examines the influence of pre-training performance on the relationship between work environment variables and transfer-related variables. Structural equation modeling was conducted with data collected from 365 Korean employees of a large general insurance firm. They were all participants in a leadership development program. The results of multi-group analyses revealed that the influence of work environment variables on transfer-related variables was moderated by employees' pre-training performance. The findings of the study imply that a more elaborate training transfer model that considers performance not just as an outcome variable, but also as an antecedent variable is required. Also, it is proposed that different strategies should be applied to promote transfer of training based on the employee's level of pre-training performance. 相似文献
56.
多项选择题作为语言测试的一种常用手段,以其诸多优点受到了出题者的青睐,这种测试手段可用来测量考生的听力水平、阅读能力,以及写作能力。与此同时,多项选择题的缺点也不容忽视。本文主要讨论了多项选择题的优缺点、干扰项的项目分析方法以及多项选择题在设计时应遵循的原则。 相似文献
57.
研究双圆盘Hardy空间子模间的重相似等价,并进一步得到两子模重相似等价的充要条件. 相似文献
58.
Uwe Dulleck 《The journal of international trade & economic development》2013,22(2):229-239
Article VI of the GATT allows counter measures if goods are sold in a foreign market at a price below average production plus transportation costs. The present article analyses Article VI based on a simple game theoretic model with two countries and economies of scale in the production of one homogeneous good. It is shown that multiple equilibria exist under the WTO rule for some parameter values that do not exist without the rule. In some equilibria, the incumbent serves the entire market even if the entrant can produce at lower costs. The model supports the criticism of the anti-dumping rule as an instrument of protection by industrialized countries against competition from developing countries. 相似文献
59.
60.
《Journal of medical economics》2013,16(9):1146-1153
AbstractObjective:To assess predictors and costs of multiple sclerosis (MS) relapse, a potential outcome measure in payer-manufacturer risk-sharing agreements for disease-modifying drugs (DMDs).Methods:A retrospective cohort analysis of medical/pharmacy claims was used. Study patients had ≥1 DMD (interferon beta, glatiramer, natalizumab) claim, without DMD claims in a 6-month pre-period before DMD initiation; were aged 18–64 years and continuously enrolled from the pre-period through a 24-month post-period; and had ≥2 MS medical claims during the 30-month study period. Post-period relapse cohorts included: (1) severe (hospitalization with MS diagnosis); (2) moderate (outpatient services including intravenous methylprednisolone); and (3) none. Poisson regression modeled severe relapse frequency, logistic regression modeled ≥1 severe relapse, and generalized linear modeling predicted healthcare costs. Tested predictors included demographics, insurance type, index DMD, pre-period health status, and DMD medication possession ratio (MPR).Results:Severe relapse was experienced by 14.5% and moderate relapse by 13.8% of 2291 patients. In logistic regression, severe relapse was predicted by plan type; age (odds ratio [OR]?=?1.018, 95% confidence interval [CI]?=?1.005–1.031); pre-period Charlson Comorbidity Index (OR?=?1.307, 95% CI?=?1.166–1.464); pre-period proxy measure indicating impaired activities of daily living (OR?=?1.470, 95% CI?=?1.134–1.905); pre-period MS hospitalization (OR?=?2.174, 95% CI?=?1.537–3.074); and DMD non-adherence (MPR OR?=?0.101, 95% CI?=?0.068–0.151). Poisson regression results were similar. Predicted mean [standard deviation] all-cause healthcare expenditures were tripled for patients with severe compared with moderate relapse ($48,173 [$8665] and $13,334 [$1929], respectively).Limitations:Commercially insured patients from a single payer; use may have been inconsistent with approved indications; proxy relapse measure may have misclassified patients.Conclusions:Severe MS relapses requiring hospitalization, although affecting less than 15% of patients initiating DMD treatment, are associated with high medical costs. The only actionable predictor of severe relapse identified in observational analysis was MPR, raising questions about the feasibility of using observational data to guide outcomes-based contracting. 相似文献