The effects of individually varying times of observations on growth parameter estimations in piecewise growth model

When using latent growth modeling (LGM), researchers often restrict the factor loadings, while the multilevel modeling (MLM) treats time as a metric variable. However, when individually varying times of observations are concerned in the longitudinal studies, the use of specified loadings would lead to inaccurate estimation. Based on piecewise growth modeling (PGM), this simulation study showed that (i) individually varying times of observations with larger boundaries got worse estimates and model fits when LGM was used; (ii) estimating the PGM across all the simulation situations was robust within MLM, whereas LGM got identically equal estimation with MLM only in the case of time boundaries of ±1 month or shorter; (iii) larger change of slope in piecewise modeling indicated better estimation.     

互联网时代媒体融合发展的未来模式探索

以互联网技术为引领的新技术为传统媒体的发展带来了新的机遇与挑战.从历史的角度看,传播媒介的发展轨迹与技术变革的历史脉络相互印合.媒体融合的层次与内涵日渐丰富,产业实践中呈现出复杂的博弈与协作关系.传统媒体独特的版权资源与人才储备优势,与新兴媒体的传播渠道及传播效率优势相结合,互相推动,深入协作,通过媒介融合渠道,实现优秀的人才、优质的内容与优化的传播平台的整合,以形成迸发式的传播威力,推动传播层次的迭代发展.面向技术发展前景的媒体融合,应当秉承开放与共享的新思维、立体与互动的新路径,注重以用户为中心,充分利用技术的便捷性,实现媒介传播渠道的多层次性与互动性,超越阶段性的固有技术模式,以踏准未来的节拍.     

实物资金流量表的预测方法研究

资金流量表是国民经济核算体系中的重要组成部分。然而，由于在编制过程中需要采集大量的数据，通常情况下，很多国家的资金流量表都会有较长时间的滞后。在编制实物资金流量表的延长表时，已有方法通常是基于基期与预测期交易收支结构保持不变的假定条件。然而，经济结构发生显著变化时，该类方法就会失效。基于上述问题，研究弱化模型的假设条件，并提出了新的实物资金流量表预测方法( 简称 FPTF方法)。根据表中元素必须满足的约束条件，该方法通过建立数学模型解除约束，其次基于历史数据的动态趋势，采用适当的时间序列分析方法来预测目标年份的实物资金流量表。通过仿真分析，验证了所提方法的有效性和稳定性。此外，基于中国1992年～2014 年的实物资金流量表数据进行实例分析，取得了满意的分析结果。     

信息时代高校外语教师职业发展新模式

文章简要陈述了信息时代高校外语教师职业发展趋势和信息时代对高校外语教师职业发展的挑战，并再对信息时代高校外语教师职业发展新模式的实现途径进行了有效探究。     

需求分布规律变化情况下的报童订货策略

在需求分布规律变化情况下，报童在进行订货决策时会因为错误判断需求分布规律而导致期望库存成本增加。为了解决这一问题，本文集成传统历史需求信息和非传统需求信息以正确地认知需求分布规律，在此基础上决策订货量。假设需求服从均值不同、方差相同的两种类型的正态分布，每一种正态分布的概率已知。利用信号检测理论构建基于历史需求信息与需求分布概率的报童最优订货策略，并与只基于需求分布概率的直觉规则订货策略进行对比。结果表明：只要排除需求分布概率很大或很小两种极端情况，最优订货策略比直觉规则订货策略在控制期望库存成本方面的作用更明显，即利用历史需求信息可以有效修正报童对实际需求分布的检测结果，从而提高实际订货决策的准确性。研究结果对传统历史需求信息和非传统需求信息的集成以及需求信息交换等有一定的管理学启示和应用价值。     

Media Disaster Reporting Effects on Public Risk Perception and Response to Escalating Tornado Warnings: A Natural Experiment

Previous research has evaluated public risk perception and response to a natural hazards in various settings; however, most of these studies were conducted either with a single scenario or after a natural disaster struck. To better understand the dynamic relationships among affect, risk perception, and behavioral intentions related to natural disasters, the current study implements a simulation scenario with escalating weather intensity, and includes a natural experiment allowing comparison of public response before and after a severe tornado event with extensive coverage by the national media. The current study also manipulated the display of warning information, and investigated whether the warning system display format influences public response. Results indicate that (1) affect, risk perception, and behavioral intention escalated as weather conditions deteriorated, (2) responses at previous stages predicted responses at subsequent stages of storm progression, and (3) negative affect predicted risk perception. Moreover, risk perception and behavioral intention were heightened after exposure to the media coverage of an actual tornado disaster. However, the display format manipulation did not influence behavioral responses. The current study provides insight regarding public perception of predisaster warnings and the influence of exposure to media coverage of an actual disaster event.     

一类稀疏投资组合双层参数估计模型及其应用

带基约束的投资组合问题是近年来投资组合领域的热点问题，但是参数不确定性直接影响了模型的效果。带基约束的投资组合问题所涉及的参数不仅包括以往研究认为非常重要的预期收益率，还包括控制投资组合规模的稀疏度，尤其是最优稀疏度估计方面的专门研究还十分匮乏。为了使带基约束的投资组合模型更好地为投资决策服务，本文从投资者效用出发，用双层规划的思想构建了带基约束的投资组合双层参数估计模型。然后根据模型的特点，设计了无导数优化算法框架，并基于ADMM对算法子问题进行求解。本文实验针对真实的市场数据给出了预期收益率和最优稀疏度的估计，接着通过与等权重策略和含上下界约束的均值-方差模型进行比较，说明了模型及算法的有效性和实用性。最后，将本文提出的双层参数估计模型推广到了更一般的形式。     

基于多目标加权灰靶决策模型的节能服务公司选择研究

用能方对节能服务公司（Energy Service Company，ESCO）的选择关系到合同能源管理（Energy Performance Contracting，EPC）能否顺利实施。从用能方的角度，采用灰色系统理论中的多目标加权灰靶决策模型，对存在多决策目标的ESCO选择问题进行研究。通过层次分析法确定ESCO的11个决策目标的决策权数，根据综合效果测度值的比较，最终实现最优对策的选择。本文为用能方的ESCO选择问题提供了一种新的思路。     

Learning,signaling, and convincing: The role of experimentation in the business modeling process

This study examines experimentation in the business modeling process, unpacking three different roles of experimentation: learning, signaling, and convincing. Learning is an inherent role of experimentation, as managers typically experiment to engage with the environment and to obtain knowledge. This study uncovers another set of roles, which have a symbolic nature. These roles show that experimentation is not just a learning process, but also a strategic legitimation process, aimed at enacting the environment. Experimentation serves the purpose of signaling to potential customers and other stakeholders, and of convincing them to embrace the business model. Furthermore, this study shows that experimentation takes two forms—purposeful interactions and experimental projects—and that these forms can support the different roles of experimentation.