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71.
文进军 《长沙理工大学学报(社会科学版)》2007,22(1):9-11
邓小平后勤思想作为一个理论体系,不仅具有丰富的内涵,且有一个明晰的形成历程,邓小平在汲取古代后勤思想和毛泽东后勤思想的基础上,对后勤工作的地位和作用有自己独特的理解和认识,为后勤工作提供了不竭的理论源泉。 相似文献
72.
73.
无法识别创业风险是导致创业失败的主要原因之一,如何有效识别并管理创业风险是新创企业健康成长的关键.社会网络能够弥补创业者在识别风险过程中的信息劣势,但既有研究极少探索社会网络是否以及如何影响创业风险识别.为弥补这个研究空白,文章利用信息处理理论为研究框架,构建了创业风险识别模型.具体而言,结构洞和网络强度有利于创业者获取更多、高质量与风险相关的信息,进而识别更多的创业风险;获取信息的数量在网络强度与创业风险识别关系之间发挥完全中介作用;创业者的先前经验正向影响创业风险识别,并对结构洞与获取信息的数量之间关系起调节作用.文章讨论了研究结果的理论贡献与实践启发. 相似文献
74.
Zengyan Fan 《Journal of nonparametric statistics》2017,29(3):561-576
In this paper, we investigate the commonality of nonparametric component functions among different quantile levels in additive regression models. We propose two fused adaptive group Least Absolute Shrinkage and Selection Operator penalties to shrink the difference of functions between neighbouring quantile levels. The proposed methodology is able to simultaneously estimate the nonparametric functions and identify the quantile regions where functions are unvarying, and thus is expected to perform better than standard additive quantile regression when there exists a region of quantile levels on which the functions are unvarying. Under some regularity conditions, the proposed penalised estimators can theoretically achieve the optimal rate of convergence and identify the true varying/unvarying regions consistently. Simulation studies and a real data application show that the proposed methods yield good numerical results. 相似文献
75.
Paul‐Anthelme Adèle 《International social security review》2017,70(1):3-17
The possession and use of a personal social security number helps to structure people's daily lives. However, despite its fundamental normative importance, the social security number remains a little‐known entity. Increasingly universal and yet diverse in form, it is a legal and technical norm which is as much a mechanism for surveillance and monitoring as it is a necessary instrument for giving effect to social rights. Analysis of this constituent element of social security systems permits as assessment of some of the technical difficulties presented by the ever‐increasing movement of people and data. Overcoming these technical difficulties should permit to envisage a first technical step towards realizing a universal and global social security system. 相似文献
76.
Binbing Yu 《Journal of applied statistics》2009,36(7):769-778
In disease screening and diagnosis, often multiple markers are measured and combined to improve the accuracy of diagnosis. McIntosh and Pepe [Combining several screening tests: optimality of the risk score, Biometrics 58 (2002), pp. 657–664] showed that the risk score, defined as the probability of disease conditional on multiple markers, is the optimal function for classification based on the Neyman–Pearson lemma. They proposed a two-step procedure to approximate the risk score. However, the resulting receiver operating characteristic (ROC) curve is only defined in a subrange (L, h) of false-positive rates in (0,1) and the determination of the lower limit L needs extra prior information. In practice, most diagnostic tests are not perfect, and it is usually rare that a single marker is uniformly better than the other tests. Using simulation, I show that multivariate adaptive regression spline is a useful tool to approximate the risk score when combining multiple markers, especially when ROC curves from multiple tests cross. The resulting ROC is defined in the whole range of (0,1) and is easy to implement and has intuitive interpretation. The sample code of the application is shown in the appendix. 相似文献
77.
Doubly adaptive biased coin design (DBCD) is an important family of response-adaptive randomization procedures for clinical trials. It uses sequentially updated estimation to skew the allocation probability to favor the treatment that has performed better thus far. An important assumption for the DBCD is the homogeneity assumption for the patient responses. However, this assumption may be violated in many sequential experiments. Here we prove the robustness of the DBCD against certain time trends in patient responses. Strong consistency and asymptotic normality of the design are obtained under some widely satisfied conditions. Also, we propose a general weighted likelihood method to reduce the bias caused by the heterogeneity in the inference after a trial. Some numerical studies are also presented to illustrate the finite sample properties of DBCD. 相似文献
78.
Two-stage designs offer substantial advantages for early phase II studies. The interim analysis following the first stage allows the study to be stopped for futility, or more positively, it might lead to early progression to the trials needed for late phase II and phase III. If the study is to continue to its second stage, then there is an opportunity for a revision of the total sample size. Two-stage designs have been implemented widely in oncology studies in which there is a single treatment arm and patient responses are binary. In this paper the case of two-arm comparative studies in which responses are quantitative is considered. This setting is common in therapeutic areas other than oncology. It will be assumed that observations are normally distributed, but that there is some doubt concerning their standard deviation, motivating the need for sample size review. The work reported has been motivated by a study in diabetic neuropathic pain, and the development of the design for that trial is described in detail. 相似文献
79.
Jackie Sanders Robyn Munford Linda Liebenberg Michael Ungar 《Child & Family Social Work》2017,22(1):3-14
The contribution peer relationships make to positive adolescent development is well recognized. Accordingly, peer problem measures typically assess youth with few age‐appropriate peers as having peer problems. Yet, youth facing high levels of personal and/or social adversity may reduce their association with antisocial peers as part of coping or risk mitigation strategies. While such strategies will result in higher scores on peer problem measures, they may also facilitate resilience and constitute a resource social workers can draw on in their work with youth. To test this proposition of peer adaptation as a risk mitigation strategy, mixed‐methods data relating to two groups of youth who were exposed to different levels of adversity were compared on a standardized peer problem measure and a range of risk measures. Qualitative interviews extended this data and explored vulnerable youth perceptions of social withdrawal as a coping strategy. Results from the survey and qualitative data indicated that a subgroup of youth facing high levels of adversity restricted association with antisocial peers to reduce their behavioural risks. However, without adequate support from adults in both formal support systems and youths' social ecologies to compensate for the loss of peer friendships, this strategy did not reduce behavioural risk in the medium term. The social withdrawal strategy also appeared to heighten mental health concerns for these youth. The implications of this finding for the development of policy and practice with vulnerable youth are discussed. 相似文献
80.
V.G. Vinogradskii 《Russian social science review : a journal of translations》2017,58(4-5):453-466
This article spells out the methodological considerations and various procedural and methodological subtleties developed over the author's quarter century of sociological field studies of Russia's peasant worlds. Particular attention is paid to “voices from below”—peasant discursive formats that capture, in natural and undiluted form, the evolution of peasant practices constituting the core of everyday life. In particular, the phenomenon of generational sorrow and a special chronological nostalgia that functions as a “social gyroscope” is identified and discursively captured. This phenomenon is noteworthy and useful for its ability to retain a record of the productively longed for past in a rural community's collective memory and thereby influence new peasant worlds taking shape today. 相似文献