平台经济视域下的商家投机行为治理——基于平台主动治理视角

平台型网络市场的虚拟性与隐蔽性导致商家隐瞒、欺骗消费者的行为愈演愈烈，衍生了新的治理难题。基于交易成本理论和社会交换理论，立足平台主动治理视角，文章探索平台主动治理中的事前商家规范机制、事中交易保障机制和事后争议处理机制对商家强、弱投机行为的影响，以及平台声誉对其影响的调节作用。基于消费者视角开展问卷调查，对数据进行结构方程模型分析和分层回归分析，结果表明：弱投机行为对强投机行为具有显著正向影响；商家规范机制和争议处理机制对强、弱投机行为均具有抑制作用；而交易保障机制对弱投机行为具有促进作用；平台声誉对交易保障机制、争议处理机制和弱投机行为之间的关系具有负向调节作用。     

基于大规模街景图片人工智能分析的精细化城市修补方法研究

在中国快速城镇化阶段“重量”而“轻质”的建设过程中，城市建成区尤其是老城区的景观环境产生了诸如景观视廊受阻、风貌破败等大量问题。对此，自2015年中央城市工作会议以来，各地相继开展了城市修补专项规划，以修复及更新城市建成环境，促进城市空间品质提升。然而，由于缺乏对城市环境整体效应的统筹考虑，故在城市实际修补过程中，城市局部地块的品质提升反而对城市整体品质构成负面影响。因此，在人工智能及大数据技术深度介入城市规划和设计实践探索的基础上，研究基于全卷积神经网络模型(FCN)和城市场景要素深度学习数据集，对城市景观环境中的各要素进行了大规模且高颗粒度的精确识别，同时与空间数据叠加，对复杂建成环境中的景观问题进行精确分析，并基于分析成果辅助后续城市规划设计实践，逐层递进地对城市复杂建成环境进行精细化修补。选择位于嵩山脚下的登封市作为案例，探索人工智能技术在辅助城市修补等规划领域的前瞻性应用。     

Time preference and international trade

We first consider a closed model, where households' time discount depends on externality in consumption. We can prove that there is a unique steady state, which is a saddle point. Then we extend the model to a two‐country world, and derive the condition on the effects of consumption externality under which there is a unique free trade steady state with saddle‐point stability.     

市域(郊)铁路车辆选型方案探讨

随着城镇化进程的加快和城市经济辐射能力的增强,以特大城市中心城为核心的都市圈逐渐形成,都市圈内的经济联系更加紧密,都市圈核心区与外围的出行需求迅速增长,市域(郊)铁路的概念被引进,选择符合市域(郊)铁路特点的车辆类型是设计的重点。     

Operating efficiency in Chinese universities: An extended two-stage network DEA approach

The result shows that it accepts the null hypothesis. Namely, there is no significant difference in the operating efficiency of universities in different regions. That is to say, although the efficiency of the central and western universities is slightly better than that of the eastern universities in terms of the average efficiency, there is no significant efficiency difference among the eastern, central, and western regions statistically. Therefore, it shows a balanced development trend for the efficiency of universities in different regions.     

Knowledge distance and R&D collaboration in Cournot oligopoly

A Cournot collaboration game is complemented with the hypothesis that the cost of R&D collaboration depends on firm’s directed knowledge distance with respect to potential R&D partners. The further hypothesis that directed distance may be non‐uniform and pair‐wise asymmetric reconciles theoretical predictions with qualitative evidence about concentration and multiplicity of components in industrial R&D networks. The welfare properties of sparse stable networks are also affected.     

Enhanced network effects and stochastic modelling in generation expansion planning: Insights from an insular power system

Electricity generation capacity expansion is driven by both economic and socio-political realities. Policy makers determine public infrastructural decisions, such as climate and renewable targets, and transmission infrastructure, and the optimal generation capacity expansion follows. Policy makers therefore require planning models that can determine the optimal generation capacity mix in the long run under various scenarios, including policy choices. This work presents a planning model based on linearised alternating current optimal power flow which determines optimal generation capacity expansion and operation, in a least-cost manner, given global and local technical constraints, as well as policy decisions. We apply the model to a test case of the island of Ireland, which has two weakly interconnected systems, high renewable generation targets and low storage and interconnection. We determine the optimal generation expansion and operation out to 2030 considering the effects of increased multi-area interconnection, existing fossil fuel generation phase-out and increased renewable generation targets and carbon prices. Our results find that costs and emissions are driven primarily by the decommissioning of old inefficient generation units. High renewable targets, on the other hand, render increased carbon prices relatively ineffective in reducing system emissions. Furthermore, high renewable generation targets crowd out low-carbon power generation options such as carbon capture and storage (CCS). The strategic north-south interconnection has little effect on renewable energy source installations required to achieve renewable power generation targets but does impact on security of supply and the congestion level across the island.     

Beyond the community in participatory forest management: A governance network perspective

Governance of the environment and natural resources involves interests of multiple stakeholders at different scales. In community-based forest management, organisations outside of communities play important roles in achieving multiple social and ecological objectives. How and when these organisations play a role in the community-based forest management process remains a key question. We applied social network analysis to a case study in Indonesian Borneo to better understand the evolution of interactions between organisational actors, and with communities. NGOs featured most prominently in initiating the permit process, implementing management, and providing other support activities, while also being well-connected to donors and government actors. The network configurations indicated significant cooperation among organisations when initiating the community forest process, while bridging between village and organisational levels characterised all stages of the community forest process. While community-based forest management often evokes images of grassroots efforts and broad local capacity to manage forests, reality shows a more dynamic and heterogeneous picture and broader involvement of different actor types and motivations in Indonesia. These findings can be applied to other countries implementing and expanding their decentralised forest policies.     

新时代中国城市土地集约利用若干问题的再认识

研究目的：基于中国城市土地集约利用研究现状，面向新时代要求，重新审视与厘清城市土地集约利用理论认知、评价标准、影响机制和优化调控等基本问题，为中国土地集约利用的理论完善和实践创新提供支撑。研究方法：理论分析法和推理演绎法。研究结果：（1）城市土地集约利用在理论认知上应由“三个阶段”转向“三个时期”；（2）城市土地利用集约度的评价标准应由静态指标转向动态耦合；（3）城市土地集约利用的影响机制研究应由封闭区域转向关联传导；（4）城市土地集约利用优化调控策略应由极限集约转向最优集约。研究结论：进入新时代，城市土地集约利用理论上可实现“不增地，多增效”甚至“地减量，效增加”，未来相关研究应重点关注存量和减量规划中建设用地与经济发展之间关系的变化特征，以及国土空间规划与土地利用计划管理改革下新的城市土地集约利用问题。国家相关规程中的集约评价标准须结合区域发展阶段进行“匹配性”修正，政策制定要考虑区域间的“关联性”和“传导性”进行精准化设计，治理方案应按照最优集约度的“动态性”进行差异化调控。     

深度学习技术在海关风险甄别中的应用研究

随着互联网的高速发展和人工智能时代的到来,越来越多从前必须由人脑完成的工作能够利用计算机技术来完成,而深度学习的出现更解决了传统机器学习算法在计算机视觉领域、自然语言处理领域表现不佳的问题,使机器也能够拥有准确感知图像和语音的能力。人脸识别是深度学习网络最常见的应用场景之一,具有自然、直接、方便的特点,且不需要检测对象配合,因此非常适合用于公共安全领域的风险检测。研究充分结合海关实际需求,搭建基于深度学习技术的人脸识别模型,提供对通关旅客进行实时风险甄别的解决方案,以及海关通关风险防控场景的理论参考,为后续深度学习技术在海关业务的研究提供支撑。