一类双曲型方程的有限差分法

利用有限差分法求解波动方程边值问题,得到了相应的稳定性分析,并进行了数值模拟.模拟结果表明;该方法求得的数值解有较高的精度和较快的运行速度.     

地方政府竞争、环境分权与环境污染--基于两步系统GMM与广义分位数的检验

随着中国经济发展水平的不断提高,环境分权对环境污染的影响有了新的变化,且这些变化多与地方政府竞争有关,因此本文利用2005-2016年省际面板数据,通过两步SYS-GMM和广义分位数对环境分权和地方政府竞争对环境污染的影响进行实证分析。结果发现：(1) 整体上环境分权、地方政府竞争与环境污染存在显著的正相关性,即环境分权体制下,地方政府竞争对环境的负面效应明显;(2)从不同的分位区间来看,地方政府竞争和环境分权对环境污染的冲击呈现出“促进低污染,抑制高污染”的倒“V”型特征;(3)地方政府竞争和环境分权对环境污染的影响在“东-中-西”空间分布上表现出抑制到促进的阶梯型转变。因此“央-地”政府应当利用现中国经济转型的战略机遇,进一步深化环境分权制度和地方政府竞争激励机制的改革,协调政府行为和环境之间的关系,为中国环境事业添砖加瓦。     

Mobile users’ information privacy concerns and the role of app permission requests

Recent privacy-related incidents of mobile services have shown that app stores and providers face the challenge of mobile users’ information privacy concerns, which can prevent users from installing mobile apps or induce them to uninstall an app. In this paper, we investigate the role of app permission requests and compare the impact on privacy concerns with other antecedents of information privacy concerns, i.e., prior privacy experience, computer anxiety, and perceived control. To test these effects empirically, we conducted an online survey with 775 participants. Results of our structural equation modeling show that prior privacy experience, computer anxiety, and perceived control have significant effects on privacy concerns. However, concerns for app permission requests have approximately twice as much predictive value than the other factors put together to explain mobile users’ overall information privacy concerns. We expect that our findings can provide a theoretical contribution for future mobile privacy research as well as practical implications for app stores and providers.     

社会规范、社会监督对农村人居环境整治参与意愿与行为的影响——基于广义连续比模型的实证分析

农户参与农村人居环境整治的意愿与行为是农村环境改善最为直接的动力,也是实现农村生态宜居和生态文明制度改革细则出台的重要依据。为细致探究农户参与农村人居环境整治的意愿与行为,本文基于社会规范和社会监督的视角,利用西藏707户调查数据,运用广义连续比模型,通过对样本数据分组,综合分析了农户人居环境整治参与意愿、行为及意愿与行为一致性的影响因素。结果显示：①农户具有参与农村人居环境整治意愿的占比略超过一半（51.77%）,但参与意愿与行为一致性较差;②邻居参与积极性、保洁员监督、村庄人居环境改善能减少疾病传播等因素对农户参与意愿与行为均产生显著的积极影响;③农户的文化程度、村民监督及政府宣传有利于农户参与意愿向参与行为转化。本文的研究结论支持了农村人居环境整治中政府主导、农户参与的整治模式,对推进农村人居环境整治具有一定的政策启示,同时对政府出台农村环境管理政策亦有一定的借鉴意义。     

Social identification,exercise participation,and positive exercise experiences: Evidence from parkrun

Growing evidence suggests that social identities may have profound implications for physical activity participation. Real-world examinations of this relationship have, however, been lacking, with research predominantly examining intentions and hypothetical scenarios. To address this shortcoming and further advance understanding in this area, the present study tested relationships between group identification, participation, two exercise-specific outcomes (exercise-specific satisfaction and group cohesion), and a broad health indicator (life satisfaction) among individuals recruited from parkrun. Participants (N = 289) completed questionnaires measuring all variables except participants’ parkrun participation, which was objectively assessed. Structural equation modeling demonstrated that group identification was significantly associated with greater participation, exercise-specific satisfaction, group cohesion, and life satisfaction. Findings provide real-world evidence of the health-related benefits associated with forming strong social identities in exercise settings.     

Application of time-temperature superposition method in thermal aging life prediction of shipboard cables

The life of shipboard cables will decrease due to the complex aging processes. In terms of the safety perspective, remaining life prediction of the cable is essential to maintain a reliable operation. In this paper, firstly, based on Arrhenius equation, residual life of new styrene-butadiene cable is calculated; result indicates that the degradation rate which changes with time is proportional to thermal temperature. Then second order dynamic model is adopted into the residual life prediction, combined with the time-temperature superposition method （TTSP）, and a new residual life model is proposed. According to the accelerated thermal aging experiment data and Arrhenius equation, TTSP method demonstrates to be an efficient way for life prediction, and life at normal temperature can be estimated by this model. In order to monitor the state of styrene-butadiene cable more accurately, an improved residual life model based on equivalent environment temperature of cable is proposed, and life of cable under real operation is analyzed. Result indicates that this model is credible and reliable, and it provides an important theoretical base for residual life of cables.     

椭圆型方程广义解的极大值原理

本文证明了方程的有界广义解u(除常数外),当以B(x,u,ζ)关于ζ增长的阶大于p-1(但不大于p)时,成立下列极大值原理:     

一种新的定压边界处理方法

依据SIMPLE算法中边界压力的外推格式,结合定压边界条件重新推导了邻近边界内节点的压力计算公式.根据NEUMANN特性给出了新的定压边界速度计算公式,用IDEAL算法来处理压力和速度的耦合.讨论了定压边界流动传热问题的求解步骤.通过几个经典算例将本方法与文献方法进行了对比,结果表明本方法提高了定压边界问题数值解的精度,加快了迭代过程的收敛.     

电子政务服务外包潜在风险对其模式选择的影响研究

电子政务服务外包的成功很大程度上取决于外包模式的正确选择与潜在风险的有效掌控,研究其潜在风险对外包模式的影响对外包模式选择、风险防范具有较高的参考价值。在分析总结电子政务服务外包主要模式(BOT、BOO、BT、ASP)的关键成功因素和潜在风险因素的基础上,构建潜在风险影响外包模式选择的结构方程模型,分析"决策与合同管理风险"、"开发与运营管理风险"、"资金与成本管理风险"、"知识与战略管理风险"四类潜在风险对各外包模式的作用机制及影响程度,并依此提出外包模式选择的参考建议。     

基于S-SEM的区域创新系统影响因素和路径研究

    创新是驱动经济增长和提高区域经济竞争力的一个关键因素,是保持经济持续增长的一个主要驱动力,在经济转型时期有必要研究创新影响因素及创新策略,增强区域科技创新能力。现有文献主要从创新影响因素、区域创新空间特征、区域创新效率、创新对企业的影响等方面展开研究,取得了相关研究结论和成果。区域创新系统是一个多因素交互作用复杂社会系统,并且存在空间溢出效应,因此研究区域创新系统有必要考虑不同要素之间的交互作用效应和空间溢出效应对区域创新的影响。基于相关理论分析提出九个假设,建立了广东省区域创新系统的空间结构方程模型,从创新主体、创新要素、创新政策、内部经济环境、外部经济环境、专利申请、新产品销售交互作用视角下实证分析广东省区域创新系统影响因素和路径。以广东省21个市域创新数据为样本,基于ESDA方法分析了广东省区域创新系统空间特征和空间相关性,基于空间结构方程模型研究了广东省区域创新系统影响因素和影响机制。通过研究得到以下结论：1）创新政策、创新要素和外部经济环境对广东省区域创新系统具有正向影响,创新政策影响最大;2）创新主体对广东省区域创新具有不利影响;3）内部经济环境对区域创新系统具有正向直接影响,但是考虑到各因素交互作用后对新产品销售具有不利影响;4）区域创新空间相关性对广东省区域创新系统具有正向影响。根据研究提出以下建议： 1）适当管控外资引入规模,限制有技术壁垒的外资企业,提高外资利用质量;2）改进现有高校和科研机构创新评价和激励制度,实施多元化和市场化的创新评价体系;3）建立政府主导的广东省创新系统公共平台,提供创新系统所需的信息交互、多方合作、成果交易和需求发布等功能;4）加大教育科技投入力度,营造创新氛围,增强创新人才的培养。