一种基于孪生神经网络的深度异构网络嵌入算法

针对现有异构网络嵌入方法导致的捕获关系冗余和模糊的问题,提出了一种基于孪生神经网络的深度异构网络嵌入模型。首先,基于面向关系的深度嵌入(Relation-Oriented Deep Embedding,RODE)框架构建了异构网络嵌入模型,以区分同型节点和异型节点之间的关系;其次,将同型节点与异类节点之间的相似性近似到低维空间,通过构建多任务的孪生神经网络来实现节点之间结构和语义关系的深度嵌入;最后,选取四个数据集执行典型网络挖掘任务,并与其他六种算法进行实验对比分析。实验结果表明,保持相同类型节点之间的相似性有助于提高节点分类效率,且损失函数在提高异构网络嵌入质量方面具有良好的优越性;RODE模型能够有效提高稀疏网络的嵌入质量,且具有良好的稳定性和鲁棒性。     

基于聚类算法的电子商务信息集成研究

随着我国电子商务发展的不断深入,这种新型的商业模式提高了对互联网情报信息搜索量和质的要求;元搜索引擎技术的不断进步使信息检索量有了很大的提高,但检索响应时间和检索准确度成为制约该技术在电子商务领域应用的瓶颈;本文通过基于传统的k-means聚类算法,优化了其类别选择机制获得了信息检索的高准确度和快速响应;实证结果表明,优化的k-means聚类算法具有较高的聚类质量和算法弹性,是元搜索引擎技术的有利补充。     

干旱区绿洲全要素农业水资源利用效率时空分异研究——以新疆为例

选取2004—2014年新疆14个地州市际面板数据,基于投入导向的超效率DEA模型,依托共同前沿理论方法,采用全要素水资源效率测度思路,对新疆地州市以及分区域农业水资源利用效率进行测度,并对其开展时空分异研究。研究结果表明,新疆地州市农业水资源利用效率呈现不断增长趋势,三大区域农业水资源利用效率呈现出北疆、东疆及南疆依次递减规律;南疆主要地区、乌鲁木齐市与阿勒泰地区农业用水处于无效率状态,伊犁州直属县(市)、博尔塔拉自治州农业用水处于低效率状态,克拉玛依市、昌吉回族自治州、塔城地区、巴音郭勒自治州、和田地区、吐鲁番地区等农业用水处于高效率状态。     

A Meta‐Analysis on the Elasticity of Demand for Pesticides

There is an increasing policy interest in pesticide taxation schemes as a measure to reduce harmful effects of pesticide use. The effectiveness of such tax depends, however, on the price elasticity of demand for pesticides. Moreover, information on these demand elasticities and their determinants is of crucial relevance for policy‐making and normative modeling approaches. In this article, we present a meta‐analysis based on studies that have estimated pesticide demand elasticities in Europe and North America. Our meta‐analysis reveals that the own‐price elasticities of demand for pesticides are, with a median of ?0.28, significantly smaller than zero, but also significantly larger than ?1, i.e. to be inelastic. We find that the demand for pesticides for special crops is less elastic than that for arable and grassland. In addition, the demand for herbicides is more elastic than for other pesticides. Studies that consider only short‐term horizons and little flexibility for farmers to adjust to price changes generate significantly less elastic pesticide demands. The results also indicate that more recent studies identify lower pesticide price elasticities of demand. Furthermore, we find that peer‐reviewed studies tend to find more inelastic results compared to grey literature.     

Impact of agricultural innovation adoption: a meta‐analysis

The impacts of adopting agricultural innovation and technology are widely examined. This paper synthesises 154 studies, which yielded a total of 600 estimates of the impact of adopting agricultural innovation and technology on production, social and economic outcomes. Using meta‐regression analysis, the empirical results show that the reported impact of adopting agricultural innovation and technology rises significantly over time, notwithstanding a significant publication bias. Whether studies find significant impacts of adopting agricultural innovation and technology depends on the use of experimental research designs, parametric method, endogenous switching regression and region. Our results show a large bias in the literature towards agricultural innovations and technologies that focus on high‐yielding varieties and thus, neglect other forms of complementary innovations and technologies.     

Foreword

No abstract available for this article.     

New Labour at work: long-term unemployment and the geography of opportunity

New Labour has placed great faith in active labour market policiesto address problems of long-term unemployment and poverty. Thispaper considers the effectiveness of welfare-to-work programmesin light of persistent regional employment disparities withinthe UK. It is argued that the government has proceeded froma flawed analysis of the causes and magnitude of long-term unemployment,framing the issue in terms of ‘worklessness’ andneglecting demand-side concerns of job availability and jobquality.     

Croatia and the SET-Plan： Intents and Results

Energy efficiency and environment protection are the international concern. European Union, under its energy and climate policy, adopted goals of reducing greenhouse gas emissions by 20%, and increasing the proportion of European energy which comes from renewable sources up to 20% by 2020. Until 2007, the development of these technologies in the European Union （EU） was undertaken in a dispersed, fragmented, sometimes even competing way. The Strategic Energy Technology Plan （SET-Plan） is the pillar of the EU＇s energy and climate policy aiming at development of affordable, clean, efficient, and low emission energy technologies through coordinated research. Croatian accession to the EU required meeting the main challenges as the other member states, involving increase in energy efficiency and renewable energy used as some of the basic components of sustainable development. Funding projects in the area of ecology and energy preservation, odds and prospects for public bodies and Environmental Protection and Energy Efficiency Fund （FZOEU） involvement in financial support of the projects, additional sources of funding etc., are some of the numerous questions this paper is aiming to address in order to assess the Croatian absorption capacities for the SET-Plan as one of the most important EU strategies.