广西农业生态脆弱性评价及区划研究

［目的］随着经济的快速发展，我国各地区都面临着不同程度的农业生态脆弱性，通过研究特殊地形和气候下的农业生态脆弱性，有助于为农业生态环境的综合治理提供参考。［方法］文章以广西为例，通过构建评价指标体系，采用层次分析法和熵权法确定综合权重，通过构建综合评价模型对广西农业生态脆弱性程度进行评价，利用ArcGIS对生态脆弱性进行分级，以期探究广西农业生态脆弱性的空间分布情况。［结果］权重分析结果表明水蚀面积的权重值最高为0134，年平均降水量的权重值为0113，自然环境指标相对于农业生产和经济指标对农业生态脆弱性的影响更大。区划研究结果表明广西农业生态脆弱性区域大致可分为5个区域，分别是桂西峰丛洼地带、桂东山地丘陵地带、桂中低山丘陵地带、桂东北山地、桂南沿海丘陵地带。［结论］广西农业生态环境整体来看较为脆弱，处于轻度和中度脆弱等级，但生态环境问题仍不容忽视。为了改善农业生态脆弱性，政府应实行区域的联合防治，加大对农业生态环境的监督和治理，积极探寻生态、环保的农业发展方式，调整产业结构，改善农业生态环境的状态，促进广西农业的可持续发展。     

An information-theoretic approach for forecasting interval-valued SP500 daily returns

We develop an iterative and efficient information-theoretic estimator for forecasting interval-valued data, and use our estimator to forecast the SP500 returns up to five days ahead using moving windows. Our forecasts are based on 13 years of data. We show that our estimator is superior to its competitors under all of the common criteria that are used to evaluate forecasts of interval data. Our approach differs from other methods that are used to forecast interval data in two major ways. First, rather than applying the more traditional methods that use only certain moments of the intervals in the estimation process, our estimator uses the complete sample information. Second, our method simultaneously selects the model (or models) and infers the model’s parameters. It is an iterative approach that imposes minimal structure and statistical assumptions.     

Towards the Development of a Tax System Complexity Index

Reducing tax system complexity is a common goal amongst policymakers; yet there is no commonly agreed definition of complexity. This paper seeks to fill this gap, by proposing the construction of an index of tax system complexity, conceived as a summary indicator of the overall complexity of a tax system at a particular point in time. If adopted, such an index would not only enable assessment of the changing level of a country's tax system complexity over time, but may also facilitate comparisons of the relative complexity of different countries' tax systems in future.     

Diversification and sophistication of livestock products: The case of African countries

This study assesses the level of sophistication of livestock products in Africa by evaluating technology intensity and economic complexity of each product. Using trade data from 1995 to 2012, livestock commodity exports are classified based on technology intensity. Employing a method of reflection in computing the economic complexity of export products, we find that one fifth of African livestock commodity exports are manufactured with low technology while the rest is composed of raw materials. The results also show that the ten most complex livestock commodities represent about a third of African livestock total exports while the world level is almost double this figure. Yet African countries spend a huge share of their wealth on importing complex products. The results imply that by exporting non-complex products Africa loses nearly a third of the total value of its livestock exports. To boost the value of livestock products, African countries should exploit their untapped potential while securing the domestic market to achieve import substitution. This can be done by integrating with global value chains or developing niche markets at the regional or international markets and improving productive capabilities.     

成品油销售综合经营指标三级预警机制探索--中国石油陕西销售公司的经营实践

2018年以来,中国石油陕西销售公司采用"红橙黄"经营指标三级预警机制,把复杂的量价关系、促销经营和费用成本管控,通过指标量化。一是以经营活动分析为基础,围绕业务指标、财务指标及支撑体系,建立了综合经营指标长效预警机制。二是通过大数据平台,形成业务运行数据每日监控,实现对月度指标的跟踪预警。中国石油陕西销售公司以"红橙黄"经营指标三级预警为抓手,将综合指标评价理念贯穿到经营全过程中,为生产经营活动提供了直观的决策依据,实现了提质增效的目标。     

海绵城市建设绩效评价指标体系研究

我国海绵城市建设绩效评价还处于起步阶段,急需构建科学合理的海绵城市建设绩效评价指标体系。通过对海绵城市建设全生命周期各项绩效评价内容的研究,全面选取评价指标,采用层次分析法、专家调查法给出指标权重,设置具有操作性的评价标准,建立总体级、项目级两个层级的具有针对性、科学性、完整性的海绵城市建设绩效评价指标体系,为海绵城市建设各阶段各层级的绩效监测或总体评价提供参考。     

城市居民税负感及影响因素的实证研究

根据北京市居民税负感调查所得数据,通过对居民税负感及其影响因素之间的相关性实证研究,得出结论,税负感与收入、文化程度、年龄以及对税收的了解程度等因素呈显著正相关,与是否参加社保呈显著负相关。在被调查的居民中,超过一半的居民税负感较重或很重,其中,收入越高和对税收了解的越多税负感就越重,本科学历和中年人群税负感较重,未参加社保的居民税负感较重,参加社保的居民税负感较轻。税负感研究的结论显示,居民税负感不仅与税收负担的高低密切相关,而且与国家的财政支出方向密切相关,扩大财政的民生开支是降低居民税负感的重要途径。     

农村居民幸福指数研究及路径选择——以山东省为例

立足"中国梦",按照社会主义新农村建设和2013年中央一号文件的内涵与要求,把握我国新农村建设的原则、目标和重点内容,以山东省的济南、青岛和菏泽三个农村地区为中心进行考察,基于主成分分析法研究三个地区的幸福指数,研究发现:提高农村居民幸福感的四条路径为增加农民收入、加快经济合理调整、注重人文环境、自然环境建设和提高政府信用水平。     

中国互联网发展水平测度指标体系研究

本文认为,在国家实施以信息化带动工业化战略的背景下,互联网作为信息化发展的龙头,对其进行测度具有十分重要的意义。本文从互联网基础设施、互联网普及、互联网初级应用、互联网高级应用等四个方面选取8个二级指标建立了我国互联网发展水平测度指标体系,并采用层次分析法确定各指标权重,从而为测度我国及各地区互联网发展水平,进而为政府部门制定互联网及信息化发展政策,分析各地区互联网发展差距,提供了一个较为科学的方法。     

基于主成分分析法的产业损害指标体系研究

分析产业损害指标之间的内在关联性,是利用指标体系评估产业损害的重要基础性研究工作。本文引入主成分分析法,对指标体系进行计量分析,对关联指标进行合并与简化,并在此基础上分析倾销对各类指标的实际影响,从而为产业损害的研究与实践提供理论依据。