浅谈铁路建设项目资格预审申请文件、商务标编写方法及建议

2014年以来,铁路固定资产投资每年基本稳定在8000亿元左右,对施工企业而言,要抓住当前的有利机会,争取更多的施工任务。结合当前铁路建设项目资格预审及招标的特点,简要介绍资格预审申请文件、商务标的编写方法,提出相关建议,以期为从业人员提供借鉴。     

Time-varying inter-urban housing price spillovers in China: Causes and consequences

The spatial spillovers of housing prices across regions are well documented by a large body of previous studies. This paper tries to investigate the dynamic (time-varying) evolution of spatial interactions and their underlying driving factors intensively. Using a recently developed Generalized Autoregressive Score (GAS) model, this paper examines the time-varying spatial spillovers of housing prices in 70 major and median cities of China from 2006 to 2019. We find that the GAS model can well capture the impact of time-varying critical events of Chinese real estate market on the whole. However, different regions display heterogeneous variation patterns over time. Further investigation shows that inter-regional labor mobility and trades are two major channels, accounting for 1.25% and 2.58% of the monthly standard deviations of spatial spillover effects from one city to another, respectively. We also characterize and distinguish between three time-varying patterns of spatial spillovers within different regions of China. Our results shed lights on the understanding of spatial spillovers across regional real estate markets across different city network structures within China.     

基于ANP-PP-SPA的区域洪灾风险评价模型研究

针对现有洪灾风险评价模型的缺陷与不足,从致灾因子、孕灾因子、承灾因子和减灾因子4个方面,通过对14项评价指标的分析与计算,构建洪灾风险评价体系。洪灾风险评价体系以网络层次分析法(ANP)求解主观权重,投影寻踪法(PP)求解客观权重,主客观综合权重与集对分析理论(SPA)耦合,构建基于ANP-PP-SPA的洪灾风险评价模型。以广东省英德市为例,验证洪灾风险评价模型的适用性。计算结果表明,英德市2016年的洪灾风险属于中等级别,符合英德市2016年的实际情况。洪灾风险评价模型不仅综合考虑了评价指标间的相互关系,还较好地体现了洪灾风险的模糊性和随机性,能够为区域洪灾风险决策和洪水管理提供科学依据。     

Using a Delphi approach to identify the most efficacious interventions to improve Indonesia’s forest and land governance

Improvements to forest and land governance are key to addressing deforestation and degradation of peatlands in Indonesia. While this is a priority area, the steps to achieving good forest and land governance have been under-researched. There is a need for better links between theoretically informed academic analysis and work in the field. This study drew together a panel of experts on forest and land governance using a Delphi method to discuss the underlying drivers of deforestation and peatland degradation, and correspondingly, to identify interventions to improve land and forest governance in Indonesia. Seventeen panelists with an average of more than 12 years’ experience reached agreement over four governance interventions: increasing the capacity of local communities to manage and monitor forests and natural resources (65% of panelist’s votes); identify strengths and weaknesses of community organisations and institutions, and develop strategies to improve their performance (65% of panelist’s votes); gazetting forests to clarify land boundaries and determine which areas should be village, community and state forest zone (59% of panelist’s votes); and, integrating participatory community maps into spatial plans to protect local communities and indigenous peoples’ development needs (53% of panelist’s votes). They also supported action research involving the government, private sector and communities, and political economy approaches to researching forest and land governance issues. Panelists indicated that community level approaches such as securing community forest tenure through clarifying land claims and integrating local land tenure into spatial planning had an important role in sustainable forest management.     

黑龙江森工林区林业产业结构演变趋势及优势产业选择

采用灰色预测方法对黑龙江森工林区2018—2027年林业三次产业产值进行预测,并在此基础上利用动态偏离-份额分析方法对此阶段黑龙江森工林区的林业优势产业进行选择。结果表明:2019年黑龙江森工林区林业产业结构将演变为"三、一、二"模式;林业第一产业中的林木育种和育苗、经济林产品的种植和采集业可作为优势产业进行重点发展和管理。因此,提出优化黑龙江森工林区林业产业结构的相关建议:继续巩固发展林木育种和育苗、经济林产品的种植和采集这两个优势产业;推动加工制造业向深加工、精加工的方向转变;加强林业旅游与休闲服务业的竞争力。     

重要生态用地级别评价和划定方法研究——以水源涵养为例

文章以水源涵养为例,基于水平衡评价计算方法,选择水资源禀赋类型不同的县域单元开展水源涵养型生态用地功能分级划定研究。总结现有生态保护红线划定技术方法及存在不足,致力于显化不同地区水源涵养生态用地功能绝对值差异,利用评价单元格水源涵养累计贡献值面积弹性拐点,对重要水源涵养用地级别划定方法进行改进。对河北省易县和四川省金川县的实例验证表明,此评价方法可以根据不同地区水源涵养功能特点量身确定重要生态空间规模、面积和比例。     

基于TOPSIS模型的现代农业发展水平评价*——以内蒙古自治区为例

［目的］现代农业发展是新时代背景下我国社会经济发展到一定阶段的必然选择，通过对内蒙古自治区现代农业发展水平进行评价分析，能够为其今后社会经济发展和精准扶贫提供更为有效的理论依据。［方法］以内蒙古自治区为例，构建基于熵值-TOPSIS模型的现代农业发展评价体系，通过分析2010—2018年内蒙古自治区现代农业发展总体得分值变化趋势和达标率变化趋势，评价该区域现代农业发展水平，同时结合资源指标、经济指标、科技指标和可持续发展指标等多指标要素综合分析，探究内蒙古自治区现代农业发展水平影响因素。［结果］（1）2010—2018年内蒙古自治区现代农业总体发展水平呈现上升趋势，整体发展态势较好。（2）内蒙古自治区现代农业发展资源指标、经济指标、科技指标和可持续发展指标均有较大幅度提升，但仍需进一步加强各指标的投入，尤其是科技指标的投入。［结论］内蒙古自治区现代农业发展要实现进一步发展，需要加大各指标投入，加强现代农业发展支持力度，实现该区域现代农业高效可持续发展。     

税收优惠影响企业创新产出的多元机制研究——来自中国软件与集成电路产业的证据

创新政策一直是激励企业创新的重要手段，其中税收优惠政策是一种具有市场导向性的激励政策，对企业创新具有良好的促进作用，但是政策对企业产生激励作用的原因尚不清晰。选取对我国技术突破有重要作用的软件与集成电路企业，采用2006-2018年中国A股上市公司数据，聚焦2011年国家对软件与集成电路行业的两个税收优惠政策，运用双重差分法对企业创新产出影响进行实证研究。结果发现：税收优惠政策对发明专利申请有显著促进作用，而对非发明专利申请无显著影响。融资约束、企业避税行为等是税收激励政策发挥作用的主要渠道。另外，税收优惠政策对不同规模、产权和区域企业有不同影响，税收优惠政策对大型企业、国有企业以及中西部地区企业创新产出促进作用更大。从税收优惠政策长期影响看，该政策对专利申请的影响存在时滞性，而发明专利申请在政策发生当年就显著增加。研究结论可为明晰税收优惠政策、融资约束与企业创新产出间关系提供有益启示。     

Comparison of dimension reduction methods for DEA under big data via Monte Carlo simulation

Data with large dimensions will bring various problems to the application of data envelopment analysis (DEA). In this study, we focus on a “big data” problem related to the considerably large dimensions of the input-output data. The four most widely used approaches to guide dimension reduction in DEA are compared via Monte Carlo simulation, including principal component analysis (PCA-DEA), which is based on the idea of aggregating input and output, efficiency contribution measurement (ECM), average efficiency measure (AEC), and regression-based detection (RB), which is based on the idea of variable selection. We compare the performance of these methods under different scenarios and a brand-new comparison benchmark for the simulation test. In addition, we discuss the effect of initial variable selection in RB for the first time. Based on the results, we offer guidelines that are more reliable on how to choose an appropriate method.     

Factor pricing of cryptocurrencies

In this paper, we study the cryptocurrency pricing factors. We review the literatures which state that the cryptocurrency market is weakly efficient. We use the Fama–MacBeth method to investigate the pricing factors. The classical equity-based risk factors including size, momentum, and value to growth from the Fama–French three factor model are studied. We use crypto-unique coin-to-token as a proxy for value-to-growth. For volatility risk factor category, we investigate realized volatility, skewness and jump. We also investigate liquidity factors including bid–ask, volume growth and Roll’s measure. The macro factors are found not to be an explanatory factor. The attention factor works sometimes. The factor model constructed by the significant factors explain most of the excess return of cryptocurrencies.