“功能性表达性模型”与中国警察信任——基于全国样本的多重中介与调节模型分析

功能性模型认为，提升警察信任的主要方法在于预防和控制犯罪，降低犯罪率与提升公众安全感；而表达性模型认为，提升警察信任更应注重维护社会正义与社区凝聚力。基于提出促进中国警察信任度提高的理论模型，提升公众获得感、幸福感、安全感，实现国家和社会整体安全的最终目的，采用结构方程模型验证“功能性-表达性模型”与中国警察信任关系的结果表明，功能性模型与表达性模型内部因素之间存在显著路径关系，同时功能性模型显著影响表达性模型指标进而改变公众对警察的信任程度。经调节效应分析后发现，主观社会阶层负向调节被害经历到犯罪恐惧感的直接路径，社交媒体使用负向调节犯罪恐惧感到警察信任的直接路径；在主观社会阶层和社交媒体使用的共同调节作用下，“被害经历→犯罪恐惧感→警察信任”中介路径效应值，随社交媒体使用频率的提升而增大，随主观社会阶层的升高而减小。     

Genetic distance,international experience and the performance of cross-border R&D for EMNEs

Cross-border R&D can contribute to the enhancement of independent innovation capabilities of emerging markets multinational enterprises (EMNEs) by benefiting from knowledge management. However, scant research exists examining the location impact of cross-border R&D for EMNEs on performance implications. This paper fills this important theoretical gap by building upon the literature of genetic distance in connection with knowledge management. We use a panel data of Chinese high-tech listed companies to empirically examine the impact of genetic distance on the performance of cross-border R&D and the role played by international experience. Our results reveal a positive relationship between genetic distance and the performance of cross-border R&D. Importantly, we highlight the motivation for cross-border R&D of EMNEs to acquire technical knowledge magnifies the positive effects of genetic distance and performance. Furthermore, our analysis indicates that international experience significantly enhanced the positive effect of genetic distance on cross-border R&D performance. We conclude this paper by discussing theoretical contributions to genetic distance, international management and knowledge management, as well as practical implications for cross-border R&D of EMNEs.     

京津冀城市圈公共服务供给水平测度及其区域差异分析

京津冀公共服务一体化是突破京津冀发展瓶颈,推动京津冀区域协同发展的重要抓手之一。本文以京津冀城市圈13个城市为研究区域,通过构建公共服务供给水平的评价指标体系,利用熵值法测度了2014-2017年京津冀城市圈各城市的公共服务供给水平,并对其呈现出的区域格局及区域差异进行探讨,结果显示:京津冀城市圈不同城市间公共服务供给水平差异显著,呈现出以北京和天津为中心逐渐衰减的空间格局;2014-2017年京津冀城市圈不同城市间公共服务供给水平的区域差异逐渐缩小,公共服务供给水平由不均衡格局逐渐向均衡格局演进。本文研究结果为推进京津冀城市圈公共服务协调发展提供建议参考。     

陆梁油田薄层底水油藏水平井井筒模拟研究

新疆陆梁油田呼图壁河组油藏发育一类特殊的薄层底水型油藏，其特点是油层厚度薄，构造幅度低，底水能量大，利用水平井开采，表现出无水采油期短、含水率上升速度快、产量递减大的特点。针对这些问题，采用水平井数值模拟方法，建立了考虑摩擦压力损失的水平井井筒模型，明确了摩擦压力损失对水平井的压力分布以及水平段产量的影响，在此基础上，分析研究了水平井底水锥进的水脊特征，判断了水平井出水位置，提出了封堵出水井段并结合油藏工程方法确定了水平井合理产液量，从而达到抑制底水快速锥进，减小压力损失，降低含水率上升速度的目的。     

Human Error in Autonomous Underwater Vehicle Deployment: A System Dynamics Approach

The use of autonomous underwater vehicles (AUVs) for various applications have grown with maturing technology and improved accessibility. The deployment of AUVs for under-ice marine science research in the Antarctic is one such example. However, a higher risk of AUV loss is present during such endeavors due to the extremities in the Antarctic. A thorough analysis of risks is therefore crucial for formulating effective risk control policies and achieving a lower risk of loss. Existing risk analysis approaches focused predominantly on the technical aspects, as well as identifying static cause and effect relationships in the chain of events leading to AUV loss. Comparatively, the complex interrelationships between risk variables and other aspects of risk such as human errors have received much lesser attention. In this article, a systems-based risk analysis framework facilitated by system dynamics methodology is proposed to overcome existing shortfalls. To demonstrate usefulness of the framework, it is applied on an actual AUV program to examine the occurrence of human error during Antarctic deployment. Simulation of the resultant risk model showed an overall decline in human error incident rate with the increase in experience of the AUV team. Scenario analysis based on the example provided policy recommendations in areas of training, practice runs, recruitment policy, and setting of risk tolerance level. The proposed risk analysis framework is pragmatically useful for risk analysis of future AUV programs to ensure the sustainability of operations, facilitating both better control and monitoring of risk.     

Effect of pavement and water deficit on biomass allocation and whole-tree transpiration in two contrasting urban tree species

Urban Ecosystems - Aiming to explore the species-specific responses of biomass allocation and whole-tree transpiration in urban trees to pavement and drought, a field manipulation experiment grew...     

考虑实时预倒箱的出口箱堆场多场桥调度优化

在出口集装箱堆场的实际作业过程中，倒箱是制约场桥作业效率的瓶颈之一。为提高出口箱堆场的作业效能，减少船舶装船作业时间，采用实时预倒来降低倒箱的影响，研究出口箱堆场多场桥调度优化问题。考虑待提箱作业次序固定、场桥间保持安全距离及不可跨越的现实约束，兼顾内集卡的等待上限，侧重场桥作业过程中的实时预倒箱，构建了以带惩罚因子的内集卡总等待时间最少为目标的混合整数线性规划模型。基于问题自身的特点设计了混合和声模拟退火算法，得出了各场桥的行走路径与实时预倒箱方案。在算例实验中，通过与不考虑实时预倒箱的方案、FCFS方案以及下界进行对比，验证了考虑实时预倒箱的场桥调度模型及算法的有效性，为集装箱码头出口箱堆场的场桥调度提供参考。     

Rank aggregation using latent-scale distance-based models

Rank aggregation aims at combining rankings of a set of items assigned by a sample of rankers to generate a consensus ranking. A typical solution is to adopt a distance-based approach to minimize the sum of the distances to the observed rankings. However, this simple sum may not be appropriate when the quality of rankers varies. This happens when rankers with different backgrounds may have different cognitive levels of examining the items. In this paper, we develop a new distance-based model by allowing different weights for different rankers. Under this model, the weight associated with a ranker is used to measure his/her cognitive level of ranking of the items, and these weights are unobserved and exponentially distributed. Maximum likelihood method is used for model estimation. Extensions to the cases of incomplete rankings and mixture modeling are also discussed. Empirical applications demonstrate that the proposed model produces better rank aggregation than those generated by Borda and the unweighted distance-based models.

     

吕氏集团对汉初岭南政策的两次调整

关于吕氏集团执政期间汉朝与南越国的矛盾冲突,传统研究多集中于吕后及其称制时期,而忽视了对事件整体性的把握,即未从吕氏集团执政的全过程加以审视。事实上,吕氏集团对南越国的政策存在两次重要调整,一是吕后时期从怀柔转向对抗,二是"诸吕"时期从南征转为罢兵。吕氏集团的第一次调整只是对原有政策的过激推行,第二次调整则可能是缓和双方关系的一种尝试。但前者不顾客观现实而冒险行事,后者缺乏后续措施而加剧了危机。因此,虽然吕氏集团的两次政策调整均出于巩固政权的需要,但其冒进与盲动的行为只能导致汉朝南部藩属体系陷入空前的危机之中。