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基于非期望产出的不同职能城市土地利用效率分异及驱动因素探究 总被引：1，自引：0，他引：1
研究非期望产出条件下不同职能城市土地利用效率分异特征及其驱动因素,对于城市可持续发展具有重要意义。本文采用DEA中改进的EBM模型,测度了2004—2015年中国五大类268个城市的土地利用效率,并运用灰色关联模型探究了其主要驱动因素。结果发现：①忽视城市土地利用过程中的生态负效应,会引起对土地利用效率的高估,而考虑非期望产出,能更加真实地测算出土地利用效率;各职能城市的土地利用效率均存在较大差异,说明按城市职能类型来测度土地利用效率的科学性。②在不考虑非期望产出条件下,各职能城市的土地利用效率值曲线相对陡峭且周期性变化较多,而在考虑非期望产出条件下,效率值曲线变化相对平缓且周期性变化较少。③综合型城市主要受产业结构、土地市场化程度和环境治理能力的影响,资源型城市主要受产业结构、对外依赖程度和政府规制的影响,工业型城市主要受产业结构、土地市场化程度和地区能源结构的影响,文娱型城市主要受城镇化水平、经济发展水平和环境治理能力的影响,地方型城市主要受经济发展水平、城镇化水平和政府规制的影响。鉴于此,在提升城市土地利用效率时,应充分考虑土地的非期望产出和城市的异质性,制定出差异化的土地管理政策。 相似文献
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《资源科学》2017,(6)
针对长三角城市群工业园区动态效率研究不足的问题,本文选取16个国家级工业园区为研究样本,基于单位土地面积投入产出指标,利用VRS-DEA模型与Malmquist指数,对2010-2014年长三角城市群工业园区土地利用效率情况进行分解动态评价,并定量分析其投入产出要素改善潜力。研究发现:(1)长三角城市群工业园区在5年间的土地利用综合效率均值为0.600,仅2个工业园区在5年中均DEA有效,且地域差异明显,从效率分解变化来看,规模效率纯技术效率技术效率;(2)从动态时间序列看,5年间工业园区Malmquist生产率指数整体呈增长趋势,技术效率变化贡献最大、纯技术效率变化贡献其次,而技术进步变化拖累,说明技术改进的薄弱是影响工业园区土地利用效率的核心因素;(3)通过对5年间土地利用DEA无效工业园区的要素投入产出改善途径与潜力分析,发现以税收收入与工业产值不足为核心的有效产出不足为各工业园区DEA无效的主要原因,长三角城市群各工业园区应在保持投入规模有效性的基础上,提升工业技术效率,同时完善转型升级期间工业园区招商引资与税收制度。 相似文献
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《资源科学》2017,(4)
为了测度中国城市土地利用效率整体特征及其区域差异,探讨提升各省份的城市土地利用效率改革方案,本文选取北京、天津等15个典型省份(自治区、直辖市)为研究对象,利用方向性距离函数(DDF),在考虑非期望产出情况下,构建了城市土地利用效率的非期望产出排放效率模型和期望产出效率模型,得到各省份城市非期望产出减排潜力(1-α)和期望产出扩张潜力(β),结合(1-α)和β值,将15个典型省份分为土地利用高效区、粗放区和相对无效区三类区域。通过GML指数分析,得到三类区域在环境约束下的城市土地利用效率以及影响因素变动情况。研究结果表明:典型省份的城市土地利用效率整体呈现上升趋势,技术效率和技术进步均对城市土地利用效率产生累积正效应。三类区域城市土地利用效率增长幅度和影响因素存在较为明显的差异,高效区和粗放区土地利用效率变化特征相似,技术效率和技术进步共同推动效率增长;技术进步是影响相对无效区效率变动的根本原因,技术效率是促进相对无效区效率增长的主要动力。 相似文献
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长江经济带城市土地利用效率评价 总被引：4，自引：0，他引：4
城市土地资源的合理有效利用是经济可持续发展的重要保障。以长江经济带108个地级及以上城市为研究对象,运用三阶段DEA模型和Malmquist指数对2005—2015年城市土地利用效率进行静态和动态分析。研究结果表明：①剔除外部环境和随机误差因素对城市土地利用效率影响之后,综合效率和纯技术效率显著提高,规模效率、技术进步和全要素生产率呈现不同幅度下降;②土地利用效率整体处于较低水平,空间格局呈现下游地区显著高于中、上游地区,长江沿线以南地区显著高于以北地区的分布态势,与纯技术效率联系密切;③土地利用规模报酬空间分异明显,长江中上游地区多处于规模报酬递增阶段,而中下游地区投入冗余情况显著;④土地利用全要素生产率年均下降0.7%,前期受到规模效率和纯技术效率的抑制,后期由技术进步推动发展,各城市土地利用效率趋于均衡。 相似文献
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城市土地利用效率影响区域一体化中的要素流动方向和产业发展态势,土地利用效率的提高是驱动一体化发展的重要因素。如何有效协调长三角一体化和土地利用的良性关系,成为学界的研究热点。因此,本文基于区域一体化与城市土地利用效率的协同机理分析,构建区域一体化与土地利用效率效率评价体系,解析其时空演变特征;通过灰色关联分析验证了两者之间的关系,采用面板VAR模型探究交互响应机制。结果表明：①研究期内长三角一体化水平不断提升,“核心-外围”极化特征显著;城市土地利用效率上升明显,与一体化的演化趋势吻合。受区位条件、经济水平与资源等多种要素影响,区域一体化与土地利用效率的空间格局匹配失衡。②区域一体化与土地利用效率具有中高等级的关联度,两系统之间存在一定的关联。③长三角一体化与土地利用效率两系统间正负波动交替的非线性交互特征明显,其中区域一体化对土地利用效率具有负向累进的冲击效应,而城市土地利用效率对一体化冲击的正向增强效应逐渐减弱并收敛为0。根据上述研究结果,制定了差异化的长三角区域一体化发展和城市土地利用管控策略,以期为促进区域协调发展与城市土地高效利用提供科学参考。 相似文献
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我国区域创新系统内知识存量投入产出效率测度 总被引：5，自引：0，他引：5
本文通过应用DEA模型对我国30个区域创新系统内知识存量投入产出效率进行了测算,其结果显示我国区域创新系统内知识存量投入产出效率除部分地区外整体偏低,区域内知识资源投入产出要素的规模效率普遍呈现递减趋势. 相似文献
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以兰州市为例,根据超效率SBM模型原理,构建城市节能环保产业效率评价指标体系。以2007—2015年为评价期间,首先利用Malmquist指数对产业效率进行动态分析及要素分解,然后在全国范围内对30个省会城市(直辖市)进行区域比较。实证结果表明,兰州市节能环保产业效率整体呈现跨期波动上升趋势,其中技术进步对其贡献最大,而纯技术效率和规模效率未发挥相应作用,产业组织管理水平有待提高,产业结构有望优化;兰州市节能环保产业效率在全国居中等水平,为DEA非有效,在从业人员、清洁能源利用效率等方面存在较大冗余,在固体废弃物综合利用和城市自然生态建设等方面存在期望产出不足,而"三废"防治仍是城市节能环保产业效率改进的重点。最后,就实证结论提出对策建议。 相似文献
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基于京津冀、长三角和珠三角城市圈2013—2015年期间的面板数据,运用非期望产出SBM-DEA模型测算其在雾霾约束下和非雾霾约束下的绿色经济效率。研究结果表明,雾霾约束下三地区的绿色经济效率总体上呈现增长的变化趋势,珠三角地区年均绿色经济效率最高、长三角次之、京津冀最低。雾霾约束促使京津冀地区大多数城市绿色经济效率下降,而长三角和珠三角地区大部分城市效率上升。三地区PM2. 5和PM10的减排潜力依次下降,且京津冀和长三角地区的减霾重点在PM10上,而珠三角地区则在PM2. 5上。 相似文献
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Marjorie Armstrong-Stassen Margaret Landstrom Ramona Lumpkin 《The Information Society》1998,14(2):153-164
This study examined how students who had no prior experience with videoconferencing would react to the use of videoconferencing as an instructional medium. Students enrolled in seven different courses completed a questionnaire at the beginning of the semester and again at the end of the semester. Students at the origination and remote sites did not differ in their reactions toward videoconferencing but there was a significant difference for gender. Women reacted less favorably to videoconferencing. Compared to the beginning of the semester, students reported significantly less positive attitudes toward taking a course through videoconferencing at the end of the semester. There were no significant differences in students' attitudes toward videoconferencing across courses at the beginning of the semester but there were significant differences across the courses at the end of the semester. The results suggest the need for better preparation for both students and instructors. 相似文献
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A joint study by Prof. ZHANG Zhibin from the CAS Institute of Zoology his co-workers from Norway US Swiss have indicated that historical outbreaks of migratory locusts in China were associated with cold spells suggesting that China's projected climate warming could decrease the pest's numbers. The study was published in Proceedings of the National Academy of Sciences on September .…… 《中国科学院院刊(英文版)》2008,22(1):6-7
Ajoint study by Prof. ZHANG Zhibin from the CAS Institute of Zoology and his co-workers from Norway, US and Swiss have indicated that historical outbreaks of migratory locusts in China were associated with cold spells, suggesting that China＇s projected climate warming could decrease the pest＇s numbers. The study was published in Proceedings of theNational Academy of Sciences on 17 September, 2007. 相似文献
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Caroline Haythornthwaite 《The Information Society》2001,17(3):211-226
A computer-mediated group is a complex entity whose members exchange many types of information via multiple means of communication in pursuit of goals specific to their environment. Over time, they coordinate technical features of media with locally enacted use to achieve a viable working arrangement. To explore this complex interaction, a case study is presented of the social networks of interactions and media use among members of a class of computer-supported distance learners. Results show how group structures associated with project teams dominated who communicated with whom, about what, and via which media over the term, and how media came to occupy their own communication niches: Webboard for diffuse class-wide communication; Internet Relay Chat more to named others but still for general communication across the class; and e-mail primarily for intrateam communication. Face-to-face interaction, occurring only during a short on-campus session, appears to have had a catalytic effect on social and emotional exchanges. Results suggest the need to structure exchanges to balance class-wide sharing of ideas with subgroup interactions that facilitate project completion, and to provide media that support these two modes of interaction. 相似文献
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Electronic data interchange (EDI) provides means for interorganizational communication, creates network externalities, requires an advanced information technology (IT) infrastructure, and relies on standards. In the diffusion of such innovations, institutional involvement is imperative. Such institutions contain governmental agencies, national and global standardization organizations, local government, and nonprofit private organizations like industry associations. The last type of organizations we call intermediating institutions. They intermediate or coordinate ("inscribe") the activities of a group of would-be adopters. Unfortunately, little is known of how these organizations shape the EDI diffusion trajectory. In this article we examine one specific type of intermediating organizations?industry associations?and how they advanced the EDI diffusion process in the grocery sectors of Hong Kong, Denmark and Finland. We identify six institutional measures, placed into a matrix formed by the mode of involvement (influence vs. regulation) and the type of diffusion force (supply push vs. demand pull), that can be mobilized to further the EDI diffusion. Industry associations were found to be active users of all these measures to varying degrees. Their role was critical especially in knowledge building, knowledge deployment, and standard setting. Furthermore, institutional involvement varied due to policy and cultural contingencies and power dependencies. 相似文献
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Puay Tang 《The Information Society》1998,14(1):19-31
The increasing prospects of digital piracy has prompted the perceived need by electronic publishers to adopt technical systems of protection, and governments to reform their copyright laws. This article is a preliminary study of the management of intellectual property by electronic publishers, defined as those involved in the production of online databases, and CD-ROMs. It focuses on three main issues: (1) how electronic publishers view the increasing threat of piracy; (2) the methods of protection employed to protect intellectual property in digital format; and (3) the importance of technological protection of intellectual property in electronic publications. The analysis is based on a sample of 23 UK electronic publishers. The interviews revealed an interesting assortment of protection methods and did not show that technological protection was a preferred way. Instead, the means of protection, in addition to copyright law, comprised niche markets, pricing, trust, bad publicity, and nontechnical and technical means. 相似文献
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Milton Mueller 《The Information Society》2001,17(3):151-163
Long-standing conflict between domain name registrants and trademark holders prompted the Internet Corporation for Assigned Names and Numbers (ICANN) to create a global, mandatory arbitration procedure known as the Uniform Dispute Resolution Policy (UDRP). The UDRP has been used in 2166 cases involving 3938 domain names as of 1 November 2000. The policy gives the initiator of a complaint, generally a trademark holder, the right to choose which ICANN-accredited dispute resolution service provider (RSP) will handle the case. During the preparation of the UDRP,some feared that complainant selection would lead to "forum shopping" that might bias the results. This article performs a statistical assessment of the forum-shopping thesis and finds support for it. There are statistically significant differences in the various RSPs' propensity to take away names from defendants; there are also major differences in the number of cases brought to each RSP. RSPs who take away names have the larger share of cases. The study examines other variables that might explain differences in market share, such as price, the plaintiff's nationality, or the time taken to decide a case. It finds that nationality and time also are correlated with market share. The study concludes that shopping for a favorable outcome is an important factor in the UDRP. 相似文献
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Prof. Raymond C.K. Chen a neuropsychologist with the CAS Institute of Psychology has made novel progress in his studies of schizophrenia. His work has been reported by a recent issue of Behavioural Neurology.…… 《中国科学院院刊(英文版)》2008,22(1):15-15
Prof. Raymond C.K. Chen, a neuropsychologist with the CAS Institute of Psychology, has made novel progress in his studies of schizophrenia. His work has been reported by a recent issue of Behavioural Neurology. 相似文献
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《中国科学院院刊(英文版)》2014,(3)
<正>In Xishuangbanna,one of China’s most biodiverse regions,landscape has changed dramatically during the past three decades due to the conversion of tropical rainforest to rubber plantations.In steep areas,terraces are often constructed before planting rubber trees,which causes two important changes in the soil:the destabilization of soil in the bench terraces and the increased vulnerability of unvegetated riser faces to erosion.Few studies have documented the nature and intensity of erosion on bench terraces.Prof.LIU Wenjie and his colleagues from the Xishuangbanna Tropical Botanical Garden(XTBG)conducted a study in Menglun County(21°5′39″N,101°15′55″E),Xishuangbanna to evaluate the influence 相似文献
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Chinese Scientists Use Earth Observation Technologies to Study and Protect Wild Camels 总被引：1，自引：0，他引：1
《中国科学院院刊(英文版)》2014,(3):267-268
<正>Chinese scientists plan to apply Earth Observation technologies to protect the critically endangered wild camels(Camelus ferus).With the help of remote sensing,satellite positioning,geographical information system and wireless sensors networks,they will be able to access the distribution and population of the wild camels and protect their habitats.The project will be carried out by the International Research Center for Wild Camel Conservation,which was jointly established earlier this year by the Institute of Remote Sensing and Digital Earth(RADI)of the Chinese 相似文献
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WANG Sijia 《中国科学院院刊(英文版)》2014,(2):192-194
<正>The Paul Gerson Unna Research Group on Dermatogenomics was founded in October 2012 at the Partner Institute for Computational Biology.The ultimate goal of the group is to understand the biology of skin and skin appendages. 相似文献