自媒体时代网络热点事件的形成

近年来,以社交为基础的“自媒体”的迅猛发展使得政治、经济、文化等社会各个领域都进入了社交媒体时代,网民成为网络媒体的主体.网络成为社会民声民意集散地,当公共事件发生时,网民会通过自媒体进行意见的表达和情绪的宣泄,由此形成一些在网络上受关注的网络热点事件.本文试图从自媒体的角度探究网络热点事件的形成的基础,探索网络热点事件产生和传播的因素和规律.     

Nonparametric covariate adjustment in estimating hazard ratios

In randomized clinical trials with time‐to‐event outcomes, the hazard ratio is commonly used to quantify the treatment effect relative to a control. The Cox regression model is commonly used to adjust for relevant covariates to obtain more accurate estimates of the hazard ratio between treatment groups. However, it is well known that the treatment hazard ratio based on a covariate‐adjusted Cox regression model is conditional on the specific covariates and differs from the unconditional hazard ratio that is an average across the population. Therefore, covariate‐adjusted Cox models cannot be used when the unconditional inference is desired. In addition, the covariate‐adjusted Cox model requires the relatively strong assumption of proportional hazards for each covariate. To overcome these challenges, a nonparametric randomization‐based analysis of covariance method was proposed to estimate the covariate‐adjusted hazard ratios for multivariate time‐to‐event outcomes. However, empirical evaluations of the performance (power and type I error rate) of the method have not been studied. Although the method is derived for multivariate situations, for most registration trials, the primary endpoint is a univariate outcome. Therefore, this approach is applied to univariate outcomes, and performance is evaluated through a simulation study in this paper. Stratified analysis is also investigated. As an illustration of the method, we also apply the covariate‐adjusted and unadjusted analyses to an oncology trial. Copyright © 2015 John Wiley & Sons, Ltd.     

A simulation testing and analysis of aggregate production planning strategies

In this study, a hybrid discrete event simulation (DES) and system dynamics (SD) methodology is applied to model and simulate aggregate production planning (APP) problem for the first time. DES is used to simulate operational-level and shop-floor activities incorporated into APP and estimate critical time-based control parameters used in SD model of APP and SD is used to simulate APP as a collection of aggregate-level strategic decisions. The main objective of this study is to determine and analyse the effectiveness of APP strategies regarding the Total Profit criterion by developing a hybrid DES–SD simulation model for APP in a real-world manufacturing company. The simulation results demonstrated that the priority of APP strategies with regards to Total Profit criterion is: (1) the pure chase strategy, (2) the modified chase strategy, (3) the pure level strategy, (4) the modified level strategy, (5) the mixed strategy and (6) the demand management strategy, respectively. The APP system is first simulated under mixed strategy (basic scenario) conditions to include all APP capacity and demand options in constructed SD simulation model to show a comprehensive view of APP components and their interdependent interactions. Then, the obtained results will be used as Total Profit measure to compare with system's performance under some experimental scenarios applying different APP strategies.     

黄甫及生平事迹考辨--对陈寅恪《柳如是别传》一则重要考证的补正

陈寅恪先生<柳如是别传>发覆钱谦益、柳如是反清复明事迹,抉幽入微,颇具识见,但其有关黄甫及就是徽州人黄澍的推测,及由此得出的顺治六年冬黄甫及游吴盖为受张天禄秘使联络钱谦益抗清等一系列的推论,不免有误.黄甫及本名黄申,淮安人,与黄澍并非一人.黄甫及在明末任职鸿胪寺,明亡后为孤节遗民,放浪形骸.黄甫及多交故国遗老,虽有反清复明之意,但其访钱谦益,与清初的反清复明活动并无必然的联系.     

《新闻联播》与股市异动的关系研究——基于注意力理论的解释

利用事件研究法,检验了《新闻联播》播报上市公司的新闻对该公司股价和交易量的影响,在此基础上,基于注意力理论,分别选择Google Trends搜索指数、公司市值规模作为投资者注意力、信息不对称程度的代理指标,构建了多元线性回归模型,研究股市异动的根源.检验结果表明:《新闻联播》导致了股市异动,股价在新闻报道后第2日出现0.36％的异常上涨,第3日至第15日发生0.92％的反转;交易量也在新闻后出现了1.87倍的异动.基于注意力理论的解释性研究表明:《新闻联播》所引起的股市异动,部分是由信息效应产生的,更关键的原因在于注意力驱动下的购买压力效应.此项研究丰富了行为金融的研究视域,并对投资者的投资决策提供了科学依据.     

Multiple Spatio-Temporal Cluster Detection for Case Event Data: An Ordering-Based Approach

This article introduces a spatio-temporal distance which allows the extension of the spatial cluster detection methods of Demattei et al. (2007 Demattei , C. , Molinari , N. , Daures , J. P. ( 2007 ). Arbitrarily shaped multiple spatial cluster detection for case event data . Computat. Statist. Data Anal. 51 ( 8 ): 3931 – 3945 . [Google Scholar]) and Cucala (2009 Cucala , L. ( 2009 ). A flexible spatial scan test for case event data . Computat. Statist. Data Anal. 53 ( 8 ): 2843 – 2850 .[Crossref], [Web of Science ®] , [Google Scholar]). A review of these methods is given before we define a spatio-temporal distance. Then this distance is used for detecting spatio-temporal clusters. These ordering-based methods are compared to the scan statistic by a simulation study. The scan procedure is more powerful but it detects fewer true positives due to its lack of flexibility. Those techniques are applied to a seismic data set. This article highlights two advantages of the ordering-based methods: their flexibility and their low computational demand.     

“三鹿奶粉事件”背景下的我国食品安全监管的博弈分析

"三鹿奶粉事件"再一次给我国的食品安全问题敲响了警钟.运用博弈论的理论对食品安全的监管过程进行了分析,通过分析均衡结果与非均衡结果的经济含义指出在监管过程中"以罚代法"及"免检制"的不科学性;并从理论上对监管工作的制度设计和政策制定提出建议,主要有:综合各种措施降低监管成本;在监管过程中更加强调监管者的作用,同等地加大对违法厂商与渎职监管者的处罚力度;废除非"免检制"以及建立监管工作的长效机制.