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排序方式: 共有1014条查询结果,搜索用时 15 毫秒
1.
[目的]软硬变化区的划分是进行遥感变化检测技术识别农作物的基础。为解决人工判读方法中存在人为主观因素影响以及自动判别和交互式判别方法对不同研究区的适用性问题,该文提出基于剖线梯度变化(Profile based Gradient Change Magnitude,PGCM)进行软硬变化区划分的方法。[方法]该研究选择破碎农业景观种植区域为研究区,计算拔节期Quick Bird影像和播种期模拟影像两个时相的变化强度,从作物地块内部向外绘制剖线,利用剖线强度的梯度变化确定硬变化区(Hard change region,HCR)、软变化区(Soft change region,SCR)和未变化区(Non change region,NCR)3者间的划分阈值。[结果]从识别结果来看,PGCM能够有效在地块边界处探测到软变化像元,进而确定HCR、SCR。像元分辨率在5~60 m不同尺度下,识别HCR区混入比例为11%~16%,混入比例随着分辨率下降而降低;NCR区混入比例为3%~4%,受分辨率尺度影响不大;SCR区识别比例为74%~86%,识别精度较高,识别结果与冬小麦空间分布结果保持一致。[结论]PGCM方法能够自动、便捷地确定阈值,摆脱人工判定的主观性,有效地划分出HCR、SCR和NCR 3个区域,为进一步HCR、SCR区内的作物识别提供基础。  相似文献   
2.
This paper examines the implementation of ‘one country, two systems’ (1C2S) in the two former Western colonies, Hong Kong and Macao, as a policy innovation in managing inter-governmental relations of a large, diverse country like China. 1C2S embodies internal tensions because the Hong Kong and Chinese governments have multiple and often incompatible goals. After 20 years, these two special administrative regions (SARs) of China are gradually being absorbed.  相似文献   
3.
This paper examines the effects of inward FDI on economic growth across the Spanish regions over the period 1996–2013, paying particular attention to the ‘headquarters effect’, namely that FDI is not always registered where it is effectively made but in the region in which the firm’s headquarters is located. By estimating a panel Spatial Durbin Model to allow for the detection of spatial spillovers, two main findings are reported. First, FDI does foster economic growth. Second, only when the headquarters effect is properly addressed do spatial spillovers arise. Hence, this effect is masking the impact of regional FDI spillovers on growth, which affects the reliability of the results and, consequently, FDI policies choice. Importantly, the results are: a) robust to the way of computing the headquarters effect; b) independent of the spatial weight matrix specification; and c) confirmed when splitting FDI into different industrial and service branches.  相似文献   
4.
Land consolidation plays an important role in increasing cultivated land, improving cultivated land quality and the ecological environment, and promoting the coordinated development of urban and rural areas. However, under the conditions of three decades of land consolidation being conducted and changing urban–rural human–land relationship, the areas of improvement in the land consolidation policy of China must be studied. This article analyzes the implementation and distribution characteristics of the land consolidation project completed in Shaanxi Province in 2018. Results show that land consolidation projects in Shaanxi are mainly land reclamation projects, cropland consolidation projects, and high-standard cropland consolidation projects. The increased cultivated land is mainly from land reclamation projects and cropland consolidation projects. The land consolidation projects in Aeolian Plateau Area, Loess Plateau Area, and Da Ba Mountain Area are mainly land reclamation projects. The land reclamation projects in Guan Zhong Plain Area and Qing Ling Mountain Area account for a large proportion. The spatial distribution of rural settlement consolidation projects, and rural settlement consolidation and land reclamation projects are mainly located in Guan Zhong Plain Area and distributed in the boundary area of Guan Zhong Plain Area and Loess Plateau Area. According to the characteristics of land consolidation projects and the changes of urban–rural human–land relationship, China should be prudent in or stop advancing land reclamation to increase cultivated land; cropland consolidation and high-standard cropland construction are vital ways to achieve China’s food security; and rural settlement consolidation should be carefully conducted in remote areas under the background of urbanization.  相似文献   
5.
This study examines whether signing auditors from rice planting regions affect audit quality. Using a sample of 12,223 firm-year observations from the Chinese stock market over the period of 2004–2015, our findings reveal that signing auditors from rice regions are significantly negatively associated with the likelihood of unclean audit opinions, suggesting that signing auditors with rice culture are more likely to succumb to the managers and hamper independence, and thus are more inclined to issue favorable audit opinions, and eventually impair audit quality. Furthermore, audit firm size and industry expertise attenuate the negative relation between signing auditors with rice culture and audit quality. In addition, above findings are robust to a variety of sensitivity tests using different measures of audit quality and signing auditors from rice cultivating areas and our conclusions still stand after using the Heckman two-step approach, placebo test and differences-in-differences method to address the potential endogeneity problem.  相似文献   
6.
路幸福  陆林 《旅游学刊》2007,22(2):38-42
云南民族众多、人文和自然景观富饶,少数民族社区旅游发展起步较早,发展较成熟,在长期发展过程中,呈现出了明显的舞台化特征.在考察了大理古城、周城,丽江束河古镇,香格里拉霞给村,西双版纳傣族园等较为典型的旅游村镇的基础上,归纳认为少数民族社区旅游的舞台化特征主要体现在3个方面:社区旅游圈、东道主行为前台化和民俗节事舞台化.这种舞台化有利于少数民族传统村镇在空间特质和精神特质上的分区保护;有利于提高居民参与社区旅游发展的参与意识和传统文化意识;有利于游客在有限的时空范围内体验少数民族的风土人情.  相似文献   
7.
薛莹 《旅游学刊》2006,21(4):47-54
首次提出并研究"旅游流的区域内聚"现象.根据系统的自组织与组织原理,以江浙沪地区为例,研究在旅游流的区域自组织演化中所形成的旅游中心城市,并研究以这些旅游中心城市作为节点而形成的区域空间结构和基于这种区域形态的区域旅游空间组织.  相似文献   
8.
This paper re-examines the link between new firm formation and subsequent employment growth. It investigates whether it is possible to have the wrong type of entrepreneurship—defined as new firm formation which leads to zero or even negative subsequent employment growth. It uses a very similar approach to that of Fritsch and Mueller (Regional Studies, 38(8), 961–976, 2004), confirming their findings that the employment impact of new firm formation is in three discrete phases. Then, using data for Great Britain, the paper shows the employment impact of new firm formation is significantly positive in the high-enterprise counties of Great Britain. However, for the low-enterprise counties, it shows that new firm formation has a negative effect on employment. Of the 15 low-enterprise regions, eight are Scottish (of nine Scottish regions in our data base) and three are North East Counties (of four). Our findings imply that having the “wrong type of entrepreneurship” is indeed possible.
Pamela MuellerEmail:
  相似文献   
9.
The Changing Face of Entrepreneurship in Germany   总被引:1,自引:0,他引:1  
This paper explains individual start-up activities on the basis of both person-related characteristics and the regional context. The analysis is based upon micro data from the GEM adult population survey. Both individual and regional variables have an influence on the decision to become self-employed. There are considerable differences between nascent opportunity entrepreneurship and nascent necessity entrepreneurship. Whereas the results for opportunity entrepreneurship are in line with theoretical predictions the factors influencing necessity entrepreneurship are far more difficult to determine. The most significant change between 2001 and 2003/2004 is the reversal of the influence of a change in the regional rate of unemployment on nascent entrepreneurship activities.   相似文献   
10.
This study replicates and extends previous work by Oppenheimer and Wiesner [1990, Sex discrimination: Who is hired and do employment equity statements make a difference? Proceedings of the 11th Annual Conference of the Administrative Sciences Association of Canada, Personnel and Human Resources Division], and examined the effects of minority qualifications on hiring decisions, the effects of employment equity directives when minority candidates are less qualified and the effects of different types and strengths of employment equity directives on hiring decisions. The results indicate that when employment equity is in place, people are increasingly more likely to hire underrepresented group members, to the extent that they are more qualified. Men appear to be treated in a positively biased manner, and are more likely to be hired when they are less qualified. Women are less likely to be hired when they are under-qualified, and in the absence of employment equity directives or when there is a suggestion that women are underrepresented. Moreover, when␣employment equity directives are strengthened, there appears to be a subtle backlash for women but not for men. Eddy S. Ng is an assistant professor at Trent University. He was on faculty at California State Polytechnic University, Pomona in 2006–2007. Willi H. Wiesner is an associate professor at the DeGroote School of Business, McMaster University.  相似文献   
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