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31.
以系统理论、协同理论为理论依据,在分析物流企业资源的概念和物流企业的自组织演化过程的基础上,介绍了物流企业资源并购整合动因和模式,并从微观角度入手,阐述物流企业在资源并购整合各个相变过程中协同管理内容和层次,为中国本土物流企业进行物流资源并购整合活动提供相应的理论依据。 相似文献
32.
张孝荣 《上海理工大学学报(社会科学版)》2020,42(3):226-231
主要阐述最简方案下存活式句法理论的主要内容,并对其优势和不足做出评价。从理论构建以及语言事实分析两个视角来看,与语段理论相比,存活理论更加符合最简句法的基本理念和要求,其理论设计更为合理,语料应用范围更为宽广。除此之外,以存活理论为基础,从核心句法操作、句法特征以及句法与其他语言模块的接口等角度反思最简方案下构建句法推导理论应该注意的问题。 相似文献
33.
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
34.
For a dose finding study in cancer, the most successful dose (MSD), among a group of available doses, is that dose at which the overall success rate is the highest. This rate is the product of the rate of seeing non-toxicities together with the rate of tumor response. A successful dose finding trial in this context is one where we manage to identify the MSD in an efficient manner. In practice we may also need to consider algorithms for identifying the MSD which can incorporate certain restrictions, the most common restriction maintaining the estimated toxicity rate alone below some maximum rate. In this case the MSD may correspond to a different level than that for the unconstrained MSD and, in providing a final recommendation, it is important to underline that it is subject to the given constraint. We work with the approach described in O'Quigley et al. [Biometrics 2001; 57(4):1018-1029]. The focus of that work was dose finding in HIV where both information on toxicity and efficacy were almost immediately available. Recent cancer studies are beginning to fall under this same heading where, as before, toxicity can be quickly evaluated and, in addition, we can rely on biological markers or other measures of tumor response. Mindful of the particular context of cancer, our purpose here is to consider the methodology developed by O'Quigley et al. and its practical implementation. We also carry out a study on the doubly under-parameterized model, developed by O'Quigley et al. but not 相似文献
35.
C. J. Brien 《Australian & New Zealand Journal of Statistics》2017,59(4):327-352
Multiphase experiments are introduced and an overview of their design and analysis as it is currently practised is given via an account of their development since 1955 and a literature survey. Methods that are available for designing and analysing them are outlined, with an emphasis on making explicit the role of the model in their design. The availability of software and its use is described in detail. Overall, while multiphase designs have been applied in areas such as plant breeding, plant pathology, greenhouse experimentation, product storage, gene expression studies, and sensory evaluation, their deployment has been limited. 相似文献
36.
Adaptive phase I/II clinical trials for drug combination assessment in oncology using the outcomes of each cycle
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Many new anticancer agents can be combined with existing drugs, as combining a number of drugs may be expected to have a better therapeutic effect than monotherapy owing to synergistic effects. Furthermore, to drive drug development and to reduce the associated cost, there has been a growing tendency to combine these as phase I/II trials. With respect to phase I/II oncology trials for the assessment of dose combinations, in the existing methodologies in which efficacy based on tumor response and safety based on toxicity are modeled as binary outcomes, it is not possible to enroll and treat the next cohort of patients unless the best overall response has been determined in the current cohort. Thus, the trial duration might be potentially extended to an unacceptable degree. In this study, we proposed a method that randomizes the next cohort of patients in the phase II part to the dose combination based on the estimated response rate using all the available observed data upon determination of the overall response in the current cohort. We compared the proposed method to the existing method using simulation studies. These demonstrated that the percentage of optimal dose combinations selected in the proposed method is not less than that in the existing method and that the trial duration in the proposed method is shortened compared to that in the existing method. The proposed method meets both ethical and financial requirements, and we believe it has the potential to contribute to expedite drug development. 相似文献
37.
Patient heterogeneity may complicate dose‐finding in phase 1 clinical trials if the dose‐toxicity curves differ between subgroups. Conducting separate trials within subgroups may lead to infeasibly small sample sizes in subgroups having low prevalence. Alternatively,it is not obvious how to conduct a single trial while accounting for heterogeneity. To address this problem,we consider a generalization of the continual reassessment method on the basis of a hierarchical Bayesian dose‐toxicity model that borrows strength between subgroups under the assumption that the subgroups are exchangeable. We evaluate a design using this model that includes subgroup‐specific dose selection and safety rules. A simulation study is presented that includes comparison of this method to 3 alternative approaches,on the basis of nonhierarchical models,that make different types of assumptions about within‐subgroup dose‐toxicity curves. The simulations show that the hierarchical model‐based method is recommended in settings where the dose‐toxicity curves are exchangeable between subgroups. We present practical guidelines for application and provide computer programs for trial simulation and conduct. 相似文献
38.
针对相干光正交频分复用(coherent optical orthogonal frequency division multiplexing,CO-OFDM)系统中相位噪声引起的载波间干扰(inter-carrier interference,ICI)问题,提出了一种基于线性预处理的新判决反馈相位噪声抑制算法。该新算法改进了线性预处理部分,利用循环前缀与OFDM符号固有的相关性,在时域进行简单的线性组合运算,充分利用了OFDM符号中冗余信息。仿真分析表明,在激光器线宽为200 kHz且误码率(bit error rate, BER)为10-4时,与判决反馈相位噪声抑制算法和一次迭代的判决反馈相位噪声抑制算法相比,该新算法BER曲线的信噪比(signal to noise ratio,SNR)分别改善了3 dB和1 dB,有效地降低由ICI引起的错误平层。 相似文献
39.
认知在互动过程中不断趋同,又不断分化与超越。互动使各种不同表征的认知系统相互作用,联结建构成具有差异的统一体。在互动过程中,互动个体的认知状态经历了"初始建构者""孤独建构者"和"社会建构者"三个不同阶段。互动建构的知识并非都是真理。互动所形成的稳定语境,即具有排他性,也具有保护性。权力强加于社会,迫使个体参与权力规训的社会互动,使社会语境发生了根本性的改变,但有时权力无法抗拒原有社会语境从而默认原有社会语境的存在。 相似文献
40.
对王皓直拍横打技术在发抢段、接发抢段、相持段技术运用特点进行分析发现,反手发球抢攻是其主要进攻手段,相持中正反手均具有对拉、反拉实力,直拍横打技术起重要作用.建议王皓加强以正手为主,反手为辅的战术思想,进一步提高正手杀伤力. 相似文献