一种用于分组交换机的缓存管理算法

提出了一种用于分组交换机中的缓存管理算法DT SMA,该算法把DT和SMA结合起来,具有两者的优点。通过理论分析和仿真,得知在单优先级情况下DT SMA比SMA的公平性更好,在多优先级情况下SMA比DT更易于实现,而且同时也能获得和DT相近的性能。     

The private journey: An interpretative phenomenological analysis of exclusive breastfeeding

Background

Exclusive breast milk provides complete nutrition for a baby’s first six months of life. In Australia, breastfeeding initiation rates are high, however duration rates are low. Although numerous studies have explored the reasons behind low levels of breastfeeding, few have examined the experiences of women who maintain exclusive breastfeeding for the recommended six-month duration.

性别对“4050”失业者的失业持续时间和再就业机会的影响——运用生存模型对厦门市失业者的经验研究

本文应用生存模型中的非参数法和COX半参数法,经验分析了性别对厦门市"4050"失业者的失业持续时间与再就业机会的影响。经验分析结果表明,性别对"4050"失业者的失业持续时间与再就业机会具有比较显著的影响,男性的平均失业持续时间为21.7个月,比女性的16.9个月长4.8个月,其再就业机会是女性的0.674倍。本文认为"4050"劳动力再就业市场上的阴盛阳衰现象在于"4050"劳动力再就业市场上男性的工作机会及接受工作的概率低于女性。因此,转变就业观念,择业不挑肥拣瘦,是促进再就业和构建和谐社会的重要途径。     

The terrible twos: How children cope with frustration and tantrums and the effect of maternal and paternal behaviors

Experimental Frustration Procedures with 158 children (15–39 months) of two-parent families were conducted, with each parent separately involved. We examined diverse characteristics of children's frustration and focused on specific behaviors of how children coped and parents supported them. In addition, external observers measured child attachment security (via Attachment Q Sort) toward the mother and the father during two home visits. Children with high attachment security became frustrated later and for a shorter time, and fathers, as compared to mothers, relieved these frustration patterns and reduced them. Although 22.2% children exhibited intense frustration responses up to tantrums, levels remained unaffected by child gender, but decreased with child age. Time-lag analyses revealed that children's self-comforting behaviors reduced frustration responses only by around 20%, but self-distracting (in younger children) and pretend-playing (in older children) by around 50% and 70%. Of the parent behaviors, demonstrating reduced children's frustration by up to 40% whereas distracting and reframing by around 60% (mothers) and 80% (fathers). In general, mothers tended to protect the child from distress, whereas fathers assisted the child in coping with frustration. However, if mothers soothed and fathers encouraged, children's frustration intensified.     

Estimation of the joint survival function for three successive duration times under double truncation and right censoring

In incident cohort studies, it is common to include subjects who have experienced a certain event within a calendar time window. For all the included individuals, the time of the previous events is retrospectively confirmed and the occurrence of subsequent events is observed during the follow-up periods. During the follow-up periods, subjects may undergo three successive events. Since the second/third duration process becomes observable only if the first/second event has occurred, the data is subject to double truncation and right censoring. We consider two cases: the case when the first event time is subject to double truncation and the case when the second event time is subject to double truncation. Using the inverse-probability-weighted approach, we propose nonparametric and semiparametric estimators for the estimation of the joint survival function of three successive duration times. We establish the asymptotic properties of the proposed estimators and conduct a simulation study to investigate the finite sample properties of the proposed estimators.     

A Bayesian approach for parameter estimation in multi-stage models

Multi-stage time evolving models are common statistical models for biological systems, especially insect populations. In stage-duration distribution models, parameter estimation for the models use the Laplace transform method. This method involves assumptions such as known constant shapes, known constant rates or the same overall hazard rate for all stages. These assumptions are strong and restrictive. The main aim of this paper is to weaken these assumptions by using a Bayesian approach. In particular, a Metropolis-Hastings algorithm based on deterministic transformations is used to estimate parameters. We will use two models, one which has no hazard rates, and the other has stage-wise constant hazard rates. These methods are validated in simulation studies followed by a case study of cattle parasites. The results show that the proposed methods are able to estimate the parameters comparably well, as opposed to using the Laplace transform methods.     

关于赠与合同任意撤销权的探讨

《合同法》的诞生堪称我国法治建设进程中迈出的又一坚实步伐,可谓是民法界的一件喜事。但是,我们仍应清醒地看到,《合同法》无论在理论上还是在立法技术上仍存在一些欠缺之处,需要改进之处甚多。笔者在学习的过程中,通过比较发现,我国《合同法》关于赠与合同的一些规定颇具特色,值得深入研究和探讨。     

Long memory in intertrade durations,counts and realized volatility of NYSE stocks

We study the persistence of intertrade durations, counts (number of transactions in equally spaced intervals of clock time), squared returns and realized volatility in 10 stocks trading on the New York Stock Exchange. A semiparametric analysis reveals the presence of long memory in all of these series, with potentially the same memory parameter. We introduce a parametric latent-variable long-memory stochastic duration (LMSD) model which is shown to better fit the data than the autoregressive conditional duration model (ACD) in a variety of ways. The empirical evidence we present here is in agreement with theoretical results on the propagation of memory from durations to counts and realized volatility presented in Deo et al. (2009).     

The Nonparametric Identification of Treatment Effects in Duration Models

This paper analyzes the specification and identification of causal multivariate duration models. We focus on the case in which one duration concerns the point in time a treatment is initiated and we are interested in the effect of this treatment on some outcome duration. We define “no anticipation of treatment” and relate it to a common assumption in biostatistics. We show that (i) no anticipation and (ii) randomized treatment assignment can be imposed without restricting the observational data. We impose (i) but not (ii) and prove identification of models that impose some structure. We allow for dependent unobserved heterogeneity and we do not exploit exclusion restrictions on covariates. We provide results for both single‐spell and multiple‐spell data. The timing of events conveys useful information on the treatment effect.     

"一带一盟"对接合作视阈下贸易便利化对出口持续时间的影响研究

巩固发展同欧亚经济联盟经贸合作关系对于促进"一带一路"建设具有重要意义。文章建立了比较全面的贸易便利化三级指标体系,贴近欧亚经济联盟成员国的实际情况;采用CEPII-BACI数据库2007—2016年HS6分位产品层面数据,首先运用生存分析方法估计中国与欧亚经济联盟及成员国出口贸易关系持续时间,其次运用Cloglog模型着重考察贸易便利化对双边出口贸易持续时间的影响;进一步引入贸易便利化与区域经济一体化的交互项,考察欧亚经济联盟启动后贸易便利化对出口持续时间的影响,研究发现:中国与欧亚经济联盟出口持续时间普遍较短,中位数只有3年,贸易关系持续时间段超过1年占比为63.7%,超过2年占比为50.5%,下降幅度为13.2%,第9年时仅剩29.6%,不足三分之一,中国与欧亚经济联盟成员国的贸易关系持续时间较短且失败概率具有负时间依赖性;贸易便利化会显著降低中国与欧亚经济联盟出口贸易关系失败的风险,提高双边贸易关系的生存率,在微观层面上说明贸易便利化水平提高,跨国企业在国际贸易活动中所支付的交易成本降低,提升利润空间从而延长企业出口持续时间;贸易便利化对不同类型产品出口持续时间的影响程度具有异质性,从回归系数大小来看,从重到轻依次为劳动密集型产品、资本密集型产品和初级产品。当贸易便利化水平变化,价值链较长、国内附加值较高的劳动密集型产品和资本密集型产品更易受到贸易便利化引致的"技术外溢"效应影响,而对于初级产品来说,农业政策的影响效果大于贸易便利化水平,因此相对于资本密集型产品和劳动密集型产品,贸易便利化水平对初级产品的影响相对较低;进一步通过交互项模型发现,欧亚经济联盟启动后产生关税同盟效应,成员国间形成零关税五国区域大市场,促进内部企业生产要素和资源配置的优化,内部要素流动更加自由便捷高效,成员国可以获取更多的规模经济效益,同时促使中国出口商品更加快捷高效地向欧亚经济联盟内其他成员国转移,增加了中国企业出口意愿进而提升了贸易便利化对出口持续时间的促进作用。文章的研究凸显了贸易便利化提升出口持续时间的关键作用,对于"一带一路"背景下提升中国与欧亚经济联盟经贸合作水平具有一定的实践参考价值。