基于CLUE-S和GMOP模型的青龙满族自治县土地利用情景模拟

[目的]对青龙满族自治县未来土地利用格局进行多情景预测模拟,并探索土地经济和生态综合效益双提升目标下的土地利用发展格局,以期为区域土地资源优化配置和国土空间规划的编制提供参考。[方法]基于土地利用现状数据和社会经济统计资料,分别利用CLUE-S单模型、灰色多目标优化(GMOP)+CLUE-S模型对研究区进行了土地利用情景模拟。[结果](1)所选驱动因子对土地利用类型的解释能力较好,ROC值均大于0.7,满足Auto-Logistic回归要求,模拟检验的Kappa系数为91.03%,模拟效果比较理想;(2)到2020年,基于CLUE-S单模型的自然发展情景,研究区建设用地扩张占用耕地和林地现象突出,土地经济效益提升较大,但生态效益却呈现负增长;基于GMOP+CLUE-S模型的多目标优化情景,研究区建设用地扩张趋势得到控制,耕地、林地面积有所增加,未利用地得到较大程度开发,实现了土地经济和生态效益双提升,分别比2015年提升了3.12%和1.96%。[结论]GMOP+CLUE-S模型能够发挥两个模型各自在结构优化和空间分配方面的优点,有利于实现区域土地利用数量结构、空间布局和综合效益的协同优化。     

基于DEA的传统农耕地区农业生产效率测度*——以皖北为例

［目的］农业生产效率是衡量农业生产的重要标准，其生产效率测度结果对研究区域农业经济发展具有重要意义。［方法］文章以皖北农耕地区为研究对象，通过采集2017年统计年鉴的相关数据，构建农业生产绩效评价指标体系，并引入虚拟决策单元，运用数据包络分析（DEA）方法，从自评和他评的角度对2017年皖北各县级单元的农业经济生产效率进行测度，并基于结果的迥异进行效率、冗余及空间分异的分析。［结果］皖北地区农业生产整体效率较低，呈现出粗放式的农业生产模式； 各种投入要素配置不尽合理，皆存在不同程度上的冗余，整体上看塑料薄膜冗余最高、化肥施用的冗余最低； 空间分异显著，南北表现为由北向南逐渐降低的“S”型趋势、东西呈现出两端高中间低的扁平状“v”型空间分异特征。［结论］粗放式的农业生产导致了皖北农业生产效率整体较低，应完善生产要素配置，大力推进农业现代化建设，促进皖北地区农业整体性协调发展，提升地区农业生产效率。     

OTC trades and liquidity in the European carbon market more than meets the eye

ABSTRACT

This study investigates whether the previously reported price impact of OTC trades in the EU ETS can be attributed to their distinctively larger size (liquidity related) or to their discretionary feature (information related). The findings suggest that OTC trades induce volatility shocks that are higher in magnitude and faster resolved than those of solely high trading-intensity trades, which appears to be driven mainly by their presence, rather than by their size. An analysis of intraday price premia reveals that they are strategically placed by interacting with the organized market whenever their price and volatility impact is lower.     

The effectiveness of monetary policy and output fluctuations: An asymmetric analysis

Previous studies have investigated asymmetries in the effects of monetary policy on the real economic activity by using either vector autoregressive (VAR)-based regime-switching models with smooth transition technique or Gaussian functions to parameterise the dynamic effects of structural shocks on the economy. These kinds of VAR models assume asymmetry as a short-run relationship between the series since the long-run neutrality hypothesis of money states that monetary policy can only affect productive capacity of the economy in the short run, but not in the long run. The recent theoretical literature shows that this hypothesis is not quite right. Thus, this paper examines the extent to which monetary policy has a long-run asymmetric effect on output in a number of Organisation for Economic Co-operation and Development countries by using a nonlinear hidden cointegration analysis within a likelihood-based panel framework. The findings indicate that there is a long-run relationship between the real interest rate as an indicator of monetary policy and the growth rate of real output in five countries out of nine under review. This gives support for the view that output has responded asymmetrically to the real interest rate changes. The economic implication of our results is that monetary policy affects positive and negative output fluctuations differently.     

基于声誉效应的工程监理激励机制模型研究

为了提高工程监理工作积极性,基于Holmstrom-Milgrom模型,引入声誉效应,建立声誉效应和显性激励机制相结合的动态委托代理激励模型。分析声誉效应发挥激励机制作用条件,并与未考虑声誉效应的委托代理模型进行比较。结果表明:声誉效应在满足一定的条件下,引入声誉激励机制能够增加业主的期望收益,并且能提高监理的努力水平。最后,通过数值仿真模拟验证引入声誉效应的合理性。     

The differences in hotel selection among various types of travellers: A comparative analysis with a useful bounded rationality behavioural decision support model

This study aims to investigate the hotel selection differences among different types of travellers through online hotel reviews. Specifically, the study performs a detailed examination of the differences in hotel key factors, criterion importance and selection results among five types of travellers, namely, business, couples, families, friends and solo. Using a sample of 194,885 online reviews on TripAdvisor.com, this study identifies the hotel key factors and criterion importance by employing the term frequency-inverse document frequency algorithm and Word2Vec algorithm. Additionally, a bounded rationality behavioural decision support model with picture fuzzy information is proposed to address hotel selection problems for different traveller types. Our results suggest that different types of travellers present differences in hotel key factors, criterion importance and selection results. However, families and friends have similar hotel selection results. This study can serve as a reference for hotel managers in understanding traveller preferences and for tourism website optimisation.     

我国M2现状及未来趋势浅析

对我国当前M2快速增长的原因,从经济发展、居民储蓄和外汇储备等三个方面进行深入分析,并在此基础上对未来发展趋势进行预测分析。     

Policy Determinants of School Outcomes under Model Uncertainty: Evidence from South Africa

In this paper, we assess the determinants of secondary school outcomes in South Africa. We use Bayesian model averaging techniques to account for uncertainty in the set of underlying factors that are chosen among a very large pool of explanatory variables in order to identify the subset of explanatory variables most strongly associated with the dependent variable. Our analysis indicates that the socio‐economic background of pupils, demographic characteristics such as population groups (Black and White), as well as geographical locations account for a significant variation in pupils’ achievement levels. We also find that the most robust policy determinants of pupils’ test scores are the availability of a library at school, the use of IT in the classroom as well as school climate.     

Nuclear bombs and economic sanctions

We examine the efficacy of trade sanctions when a target's action causes an irrevocable change in the status quo; for example, sanctions to stop a target's nuclear weapons development program. We find that when a sanctioning country cannot precommit to maintain sanctions long after a target becomes a nuclear power, sanctions are not only inefficacious but they backfire, spurring a target to intensify its effort to complete the nuclear program. If the nuclear program has several stages to complete, gradually increasing sanctions as the nuclear threat becomes more imminent may also backfire even though the program is potentially stoppable when sufficient pressure is applied earlier on. We also discuss the policy implications of our analysis.