首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
1.
Urban greenspaces are multifunctional spaces, providing services to people and biodiversity. With space in urban areas being limited creation and maintenance of urban greenspaces relies on understanding the preferences of urban residents for their characteristics. Such preferences are expected to vary with current availability, and the availability of alternatives to greenspaces such as gardens or gyms. We carried out a nationwide discrete choice experiment with Scottish urban residents to estimate values associated with greenspace attributes of: recreational features; plants and natural features; trees; accessibility; time to walk from home and size, to test the hypotheses that: (i) people are willing to pay to maintain greenspace, (ii) people have willingness to pay for greenspaces with multiple functions, including features for direct use (e.g. play equipment) and biodiversity (e.g. wildflowers), (iii) willingness to pay for individual greenspace will vary according to socioeconomic characteristics and (iv) vary with the amount of greenspace or substitute facilities available. We find a positive willingness to pay to maintain greenspace in general, and higher willingness to pay for larger greenspaces closer to home, which are multifunctional and contain both direct use features (e.g. children’s play park) and biodiversity features. Although we find significant heterogeneity in willingness to pay for maintaining greenspace, this is not well explained by either socioeconomic characteristics or the availability of substitute facilities. Our results have relevance for urban natural capital accounting, and demonstrate to urban planners the importance of the design and maintenance of multi-functional greenspaces for urban populations and would benefit from future research that further explores heterogeneity, including perceptions of greenspace access and substitutes, and greenspace quality.  相似文献   

2.
Urban greenspaces--including city parks, forests, and gardens--can provide many benefits that impact human wellbeing. One such aspect of wellbeing is social cohesion, which is broadly defined as the combined reasons to stay in a particular community. Although there is an increase in studies connecting human wellbeing, social cohesion, and urban greenspace, there is limited synthesis of the three concepts. The purpose of this paper is to review how social cohesion has been used, defined, and measured in the scholarly literature. In addition, we assess the factors that hinder or enhance social cohesion in urban greenspace and opportunities for future research. We conducted a systematic literature review using the PRISMA procedures. After doing a search with keywords, we read the abstracts of 1129 articles and selected 113 that met our inclusion criteria for final in-depth analysis. We provide an overview and conceptual diagram of the factors that enhance or hinder social cohesion in urban greenspaces. Although all of the analyzed articles included social cohesion as a variable or topic of interest, only 17 of those articles clearly defined and measured social cohesion. The most impactful ways to enhance social cohesion include reducing crime, improving maintenance, and having physical space and amenities for social gatherings that cater to various demographics. Likewise, studies suggest that the perceptions of safety, level of maintenance, accessibility, and efforts to be inclusive of diverse users including cultural activities and community engagement spaces were important to social cohesion. Overall, more research is needed to better understand social cohesion and urban greenspace in developing countries, and more in-depth analysis from the perspective of diverse urban residents who use these greenspaces. The results of this study have implications for designing and managing urban greenspaces to enhance social cohesion, inclusion, and overall human wellbeing.  相似文献   

3.
Globally, accelerating urbanization has led to a severe shortage of urban green spaces. This scarcity is particularly acute in inner cities with high population densities and ratios of built-up areas. To explore park visitors’ usage and perceptions, we present the results of a survey of 681 individuals from different socioeconomic groups conducted in four small urban parks in Budapest, Hungary’s capital. The survey results found that people living near the block parks were their primary users, but many people from distant areas also visited the parks due to their good accessibility. In addition, findings show that the green components of the parks were generally more satisfactory to users than other amenities, indicating higher quality expectations for cultural ecosystem services in small urban green spaces. However, perceptions of park safety varied across socioeconomic groups, suggesting that views of safety did not necessarily reflect actual park security. Finally, while most respondents stated they would not want to contribute to park maintenance, young people, particularly neighborhood newcomers, showed greater willingness to volunteer for such work.  相似文献   

4.
In Taiwan, urban parks have mainly cared for demands associated with recreational use and landscape aesthetics, while ecological functions have often been neglected. The purpose of this study was to examine park users’ awareness of the functions of urban parks, their attitudes toward Amsterdam Bos Park as well as their preferences and support for a sustainable forest park in Taipei metropolitan area. Moreover, the study intended to inform the decision makers in Taiwan about people's perception of urban parks. The findings suggested that participants were moderately aware of the economic benefit of urban parks, and highly aware of urban parks’ benefits regarding landscape beauty, social values, health and safety, and ecological conservation. Participants moderately agreed with the financial demand, and highly agreed with the development strategy, managerial operation, and design approach of the Bos Park. In addition, participants liked the concept of the Bos Park very much, and strongly supported the establishment of a sustainable forest park in Taipei metropolitan area. Based on the findings, recommendations were made to the Taipei City government for the decision-making in the development of a metropolitan park, as well as to landscape architects in the planning and design of urban parks.  相似文献   

5.
The desire to improve urban sustainability is motivating many city planners to adopt growth strategies that increase residential density, leading to substantial changes to urban landscapes. What effect this change will have on biodiversity remains unclear, but it is expected that the role of public greenspace in providing wildlife habitat will become critical. We explored the role of urban “pocket parks” as habitat for birds, and how this role changed with increasing residential density in the surrounding neighbourhood. We found that parks in neighbourhoods with high levels of public greenspace (corresponding to less residential land) supported more bird species and individuals overall, and more woodland-dependent species, insectivores and hollow-nesters. Total greenspace area was more important (included in the best ranked models for all bird responses) than the configuration (number, average size and connectivity) of greenspace patches. The majority of species were common suburban birds, indicating that species we assume are tolerant to urban areas will be negatively affected by increasing residential density. Parks form part of an interconnected network of urban open space. For parks to continue to support a diverse native bird community, the network must be viewed, managed, and maintained in its entirety. We suggest three key management actions to improve the bird diversity values of urban greenspaces in compact cities: (1) Increase urban greenspace cover in residential neighbourhoods. (2) Increase vegetation structure in greenspace. (3) Encourage homeowners to plant trees and shrubs.  相似文献   

6.
Urban forest parks, such as Fuzhou National Forest Park (FNFP), provide residents with landscape amenities, recreational opportunities, and interaction with nature. Understanding the recreational quality of green spaces and visitors’ behaviors and preferences is essential for effective forest park conservation strategy. We aimed to assess the recreational use and amenities of FNFP and calculate the monetary value of provided services using a contingent valuation method (CVM). A total of 249 park visitors were interviewed face-to-face based on a questionnaire using entrance fee as the payment vehicle, in October 2015 and January 2016. A considerable number of protest responses may cause selectivity bias; consequently, we used models excluding protest zeros. Sample selection models were estimated using Heckman’s two-step and full information maximum likelihood methods The average willingness-to-pay (WTP) was estimated to be 13.79 RMB (equivalent to 2.00 USD) for the unconditional model, and the lower mean values were estimated for two selectivity bias corrected models. In this case, park visitors would be willing to pay an average 11.6 RMB (equivalent to 1.69 USD) per person according to the full information maximum likelihood estimate and an average 10.96 RMB (equivalent to 1.60 USD) per person by the two-step method. Respondents’ satisfaction of forest park facilities and service significantly influenced their WTP value for forest park improvements. Socio-demographic features could not effectively discriminate the protest bidders and the other non-protest bidders. Our results suggest that protesters may value the resource less than positive bidders. The high percentage of protest respondents may be due to the current free use of FNFP and payment vehicle of entrance fee. The CVM approach takes residents’ preferences into consideration and allows the study of heterogenous socio-demographic groups; thus, our data may help to develop effective management plans for improving urban forest parks in China.  相似文献   

7.
Urban greenspaces can provide a significant cooling service, which extends beyond the greenspace boundaries. Consequently, greenspaces are recognised for their ability to locally reduce the urban heat island, a phenomenon that has negative implications for the thermal comfort and health of urban citizens. However, the amount of cooling provided by a greenspace and the distance over which that cooling extends depend on factors such as greenspace size and characteristics. Based on data collected in and around eight London greenspaces, with areas ranging from 0.2 to 12.1 ha, this work models the distance and magnitude of cooling provided by each greenspace and defines the relationships between cooling extent and the size of greenspace or the areas of tree canopy and grass. Such data, illustrating the value of expanding the area of urban greenspaces and explaining how cooling relates to greenspace size/coverage characteristics, will be of use to urban planners and climatologists concerned with finding solutions to the urban heat island. Modelling was statistically valid on calm warm nights (with mean air temperatures ≥10 °C and wind speed ≤3 m s−1). On those nights, cooling distance increased linearly with increasing area of greenspace, tree canopy and grass, but the relationship between those factors and the amount of cooling was non-linear. Cooling distance was most strongly related with tree canopy whereas the amount of cooling was most strongly linked to the grass coverage. Our results suggest that a comprehensive cooling service on calm warm nights within cities with similar climate/characteristics to London may come from greenspaces with 3–5 ha, situated 100–150 m apart.  相似文献   

8.
Utilizing survey data collected using a combined travel cost – conditional behavior method, the aim of this study was to analyze the heterogeneity of preferences among the residents of a city in Finland for the services of an urban park and its stream network. More specifically, by analyzing different behavioral responses to potential changes in ecological, cultural, and commercial services, we identified different groups of visitors to the park with a latent class model. A notable result regarding the demand for services in different classes was that low-income people valued the park more than high-income respondents, making improvements in the park’s recreational potential a successful social project. We found two latent classes, the main distinguishing factor of which was the preferences associated with increasing the number of events in the park. Adding events did not increase the benefits for the first class, but for the second class it did. In relation to class membership, if visitors usually visited the park alone or if they walked or cycled to the park, this increased the likelihood of belonging to a particular visitor group. In addition, we assessed how a possible increase in services affected the recreational value of the urban park for the city’s residents. We found that both the total and net value for different urban groups depended on three factors, i.e., the number of visits, the recreational value of a visit, and the proportion of people in each visitor group. We also used the results of the study to assess the profitability of a construction and management project in the park and found that the project was socially very profitable. Although our study examined a specific park in Finland, its results could also potentially be used when planning the management of other urban parks.  相似文献   

9.
Cultural ecosystem services (CES) in urban parks are associated with nature contact willingness and health outcomes of urban residents. However, practical knowledge on how to manage urban park features to enhance CES is still lacking, especially on more detailed scales. This study developed a practice-oriented workflow for exploring design-related indicators that affect CES by considering four aspects of urban park features, including distance to elements, density of elements, land cover proportion, and landscape diversity. Then the workflow was implemented in a case study by taking six urban parks in Beijing as study areas. Three CES types were identified with outdoor social media images, including recreation value, aesthetic value, and social interaction value. Statistical analyses indicated that a combination of the four aspects of urban park features within a specific service radius was the most significant factor in explaining CES. The importance of design-related indicators for enhancing different CES types was also identified. Density of facilities, proportion of tree canopy-shaded ground, and richness of land cover types were proved important for all the three CES types and therefore could be concerned in urban park design practices. Based on these findings, this study further proposed landscape site design strategies and three adaptive design cases for enhancing different CES types, which could provide evidence-based and practical solutions for managers and landscape architects.  相似文献   

10.
The understanding of cross-cultural upon park usage is vital to be enhanced among public since findings that been discovered in the Western context are not own any similarities with the Asian context. In fact, it has been in a long run for the Western nations to primarily contextualized and conceptualized much on the literature of park usage. This study aims to look at how the people use and perceive urban parks in their daily life in the Malaysian cultural context, and also highlights the constraints faced by Malaysians while using the urban parks in the city of Kuala Lumpur. A survey consisted of 669 urban park users as the sample of the study (365 men, 304 females) aged between 18 and 73 years (M = 34.85, SD = 11.46) were conducted in five urban parks in Kuala Lumpur. Respondents were recruited based on a random sampling method, which composed of three main ethnic groups in Malaysia. Malaysians wanted to use the urban parks for multiple purposes including active activities and others. Most of them would visit the parks and spend their time in a group consisting of family members or friends rather than alone. The percentage of respondent with 74.7% stated their reason of visiting the urban park in order “to get fresh air”, followed by the factor of reducing stress and relaxing with 69.7%; and the latter reason would be “to exercise, play games or keep in shape” with 61.4%. More than 80% of the respondents claimed the parks in Kuala Lumpur are safe to be visited. This is because, majority of the respondents tend to visit the parks in group of family or friends rather than alone. In addition, most of the respondents would run their activities in parks during the weekends, which simultaneously make them to enjoy their day in such comfortable and secure way. The findings of this survey would contribute to a better understanding of the present park usage of Kuala Lumpur residents. With a better understanding of current park-visiting habits, various constraints faced by the residents related to public security and safety, the Kuala Lumpur City Hall have been suggested to develop more comprehensive strategy in order to provide engagement and urban parks stimulation for its residents. In addition, this study is also fruitful for Kuala Lumpur future parks in terms of its development, design and management.  相似文献   

11.
BackgroundParks provide many opportunities for promoting physical, social, and mental wellbeing among older adults and are therefore considered a good setting to promote healthy ageing. However, older adults are the age group least frequently observed visiting parks. To attract more older adults to parks, it is important to understand their needs and preferences for park design. The aim of this qualitative study was to gain in-depth information about older adults’ preferred park features for park visitation.MethodsSemi-structured interviews were conducted with 25 older adults aged > 60 years who visited a recently renewed urban park in Ghent, Belgium at least once since its renewal. The interviews were conducted in-park or in the nursing home adjacent to the park until saturation of information was obtained. All interviews were transcribed verbatim, pseudonymised, and analysed by inductive content analysis using NVivo 12 software.ResultsThe most preferred park activities were walking, sitting, and watching the environment. The park features liked by older adults were good quality and accessible walking paths, nature and vegetation, openness and structural layout of the park, and sufficient and good quality sitting areas. The park features that they did not like mostly related to poor park maintenance.ConclusionsThis study provides an overview of park features that older adults perceive as important for park visitation. It is the first qualitative study in Belgium to assess which park features entice older adults to visit parks, and it contributes to the limited European knowledge on this topic. The evidence can help urban planners, landscape architects, and policymakers to (re)design attractive local parks that promote healthy ageing.  相似文献   

12.
Given the importance of urban parks for recreation, it is critical to understand how they are used and perceived. Currently, relatively few studies have examined the public’s activities and preferences at the same time. Social media data are increasingly recognized as a promising data source to study these two aspects. However, little is known regarding the utility and representativeness of social media data for urban parks. In particular, a lack of understanding exists on the comparability of research results measured by bottom-up social media data and top-down official survey data in urban park studies. This research used social media data from Ctrip and Dianping and survey data from the local government agency with park visits statistics and park satisfaction surveys to understand the public’s visitation and satisfaction of 102 urban parks in central Shanghai. We first assessed the similarities between the social media data and survey data by correlation analysis. We then used the negative binomial regression model and beta regression model to examine the matches and mismatches of the different data sources in investigating factors influencing park visitation and park satisfaction. Our correlation results showed that the social media data significantly correlated with the survey data and that social media data performed better in more frequently visited parks. Our regression results showed that the water bodies, recreational facilities, and surrounding commercial facilities were the common influencing factors of park visitation and park satisfaction for all parks. While significant correlations were noticed between these two data sources, we found that the surrounding population density was negatively associated with park visitation measured by social media data but positively associated with park visitation measured by survey data. This study provides a comparative perspective to study park visitation and park satisfaction by combining social media data and official survey data. Clarifying the consistencies and inconsistencies between the social media data and official survey data is important because it could help us to understand the representativeness and potential biases of the social media data when used in visitation monitoring and satisfaction monitoring.  相似文献   

13.
Urban nature is of vital importance for human well-being in an increasingly urbanized world. Despite the wide variety of urban greenspaces, previous research has mostly focussed on parks and in particular presence of trees. Although streets are fundamental urban structures and offer an array of green elements beyond trees, the perception and valuation of other kinds of roadside vegetation by urban residents is understudied so far. This study explores the range of roadside vegetation and associated ecosystem services perceived by city dwellers in densely populated inner city districts of two German cities. Further, we explored how wild-grown roadside vegetation is valued by interviewees. Results confirmed the important role of trees but also demonstrated that city dwellers perceive a variety of cultivated and “wild” green components other than trees. Respondents attached a wide range of meanings and values to roadside greenery and showed a surprisingly high awareness of associated ecosystem services. Wild urban roadside vegetation met with high approval, although planted and maintained vegetation was preferred. Our study illustrated that trees and other elements of roadside vegetation fulfil important functions in the view of the public. For many respondents, ecological and economical functions of roadside vegetation were more important than orderliness. This indicates opportunities for enhancing the biodiversity of urban streetscapes. As public green spaces are in short supply in many cities, enhancing cultivated and wild roadside vegetation could help to deliver ecosystem services in the areas near where people move and live.  相似文献   

14.
One of the important features of cities is to provide high-quality outdoor environments for various groups of citizens. Although children are frequent users of green spaces, the knowledge and perspectives applied in planning and design of urban green spaces are mostly defined by adults. This results in spaces and practices that may limit the daily lives and creativity of urban children. Promoting child-friendly cities benefits from knowledge produced by children themselves, regarding their perceptions and experiences, as well as ideas and suggestions. This study provides empirical results concerning children’s needs and mental images for urban green spaces in two urban areas in two countries (Chengdu, China, and Ruhr Region, Germany). 765 children, ages 8–10 were surveyed through the method of empathy-based stories (MEBS). Participants were asked to use their imagination to write stories according to given scenarios. Our study shows that MEBS can be used to gather meaningful data with children, and that children are an important stakeholder group in urban planning, landscape design and management with an ability to express their diverse needs and preferences towards green spaces. Both designed green spaces (e.g. gardens, parks) and wild nature (e.g. forests, meadows) can offer a range of activities and experiences for children in their everyday lives: opportunities for play, socializing, contact with nature, aesthetic and restorative experiences, learning and exploration. Our findings include indications of children’s awareness of the diverse ecosystem services that green spaces provide, as well as of urban sustainability and livability. While we found German and Chinese children to have corresponding needs and expectations regarding urban green spaces and nature, we also found some variation. We suggest that the use of, and experiences in green spaces are linked not only to the landscape but also to conceptual-cultural contexts.  相似文献   

15.
This study identifies and analyses multiple factors that impact people’s interactions with urban greenspace in Sweden. An unrestricted, self-selected online survey was used to collect the data. The survey questions were related to individual characteristics of respondents, including socio-demographic characteristics, self-reported nature connectedness, and self-reported constraints to greenspace usage; perceived characteristics of urban greenspace, including its availability, quality, and accessibility, and benefits and problems; and preferences of respondents regarding types of urban greenspace and activities. Additionally, several spatially explicit variables were included in the analysis. A total of 2806 respondents from 208 (of 290) municipalities completed the survey. Our findings indicate that greenspace users are highly heterogeneous and utilise diverse green spaces along the urban-peri-urban gradient for various benefits. The statistical analyses identified 61 explanatory variables that affect the frequency of interactions with urban greenspace. In addition, we identify key factors that shape critical differences between frequent and infrequent urban users, such as nature connectedness, perceptions of urban greenspace functions, and their perceived accessibility. Our results highlight the complex challenge facing urban planners and managers of green spaces, who have to consider and integrate a vast array of factors influencing the willingness of increasingly diverse urban populations to interact with greenspace.  相似文献   

16.
Urban parks are among the most important urban public services. Quantifying their visitation intensity and understanding the driving forces behind their popularity is of great relevance to urban planning. We analyze the behavior of park visitors in Beijing based on phenological information extracted from social media data. Specifically, we built a dataset utilizing natural language processing techniques and co-word analysis methods to explore the connection between flowers and park visitation. Our findings revealed that: (1) According to the changing trend of visitor volumes and their peak times, urban parks can be divided into “single-peak” (visitor volumes show a single peak, with significant seasonal characteristics) and “multi-peak” (visitor volumes show multiple peaks with no obvious seasonal characteristics) parks; (2) There is an association between flowers and visitor volumes to urban parks, with a noticeable increase in the frequency of visits to parks especially in spring (i.e., during flowering); (3) Different types of flowers have varying appeal to attract visitors. Further, parks with one or few “dominant flowers” appeal to more visitors than parks without a clear dominating flower (or flowers). Our results provide implications for urban park design and management for improving their scenic qualities.  相似文献   

17.
Constructing and renovating urban parks is an effective strategy for high-density cities to satisfy residents’ needs for recreation in nature. Using Hong Kong as an example of a high-density city, the purpose of this study was to examine the associations of park and neighbourhood environments with park-based physical activity (PA) among children and examine the moderating effect of neighbourhood income in their relationships. A cross-sectional study was conducted in 32 urban parks in Hong Kong. Park-based PA and the park and neighbourhood environments were measured using systematic observation tools and the geographic information system. Neighbourhood income was extracted from the 2011 Hong Kong Population Census data on median household income. A total of 7,753 children were observed using urban parks for PA during the study. Children’s park-based PA was positively associated with the quality of supporting amenities, park safety, neighbourhood walkability, and neighbourhood quality, while the associations of park-based PA with the diversity of active facilities and park size were not significant. In addition, neighbourhood income moderated the associations of park-based PA with the diversity of active facilities, the quality of supporting amenities, neighbourhood walkability, and neighbourhood quality. These findings provide empirical evidence on the moderating role of neighbourhood socioeconomic status on the associations between park and neighbourhood environments and children’s park-based PA in a high-density city. With children’s needs for using parks for PA, our findings are beneficial for urban planners to renovate existing urban parks to enhance their utility for children living in high-density cities.  相似文献   

18.
Urban parks have been widely recognized for the critical functions they provide in enhancing health and wellbeing. However, parks are known to be inadequately provided and non-uniformly distributed in cities, leading to an increasing interest to examine spatial equity of park distribution. Such studies have mostly focused on the distributional attributes of park supply in determining spatial equity, while the role of residents’ demand is usually ignored or not adequately assessed. In addition, people’s preferences for park use were normally ignored and nearest parks were assumed as supplier of park services. Moreover, even though equity assessment is scale-dependent, few studies adopt a multi-scale assessment. We report on a study to address these gaps. A multi-scale Supply-Demand Equity Index (SDEI) was developed to assess spatial equity of park distribution from the perspective of supply and demand interactions, and data were collected at a fine scale of neighborhood level. Residents’ accessibility to their most often used parks and nearest parks were used to assess and compare supply level; while residents’ perceptions obtained from surveys and population density were used to assess and compare demand level. Results showed that supply measured by accessibility to most often used park more accurately reflects supply, and demand assessment on the basis of perception could reflect variations among different social groups and reveal otherwise hidden patterns of spatial inequity. It was also shown that SDEI could identify areas where mismatch between supply and demand occurs. We demonstrated in a single study that different definitions and approaches of quantifying spatial equity can lead to distinct conclusions, therein highlighting that the complex nature of equity requires nuanced approaches and providing a broader view of equity assessment. In addition, the implications of this study for urban park planning and management were highlighted.  相似文献   

19.
This paper examines the relationship of planning ideals of sharply defining edges between urban density and greenspace and alternative urban greening arrangements as they are manifested in a case study of exurban “lifestyle blocks” on the fringes of Christchurch, Aotearoa New Zealand. Exurban development outside Christchurch's urban growth boundary – called the “urban fence” – provides an example of tension between municipal attempts to curb sprawl and exurbanites’ desire to live in the dispersed settlements outside of urban boundaries. These struggles play out at different scales and in a range of different metropolitan contexts. This paper reports on the results of an ethnographic study of Christchurch urban fringe residents’ residential land-use narratives and practices. The paper focuses on landscape preferences and concerns of a sample of small-scale productive land users and explores the implications of their versions of urban greening in the context of policy visions for the urban edge. A political ecology interpretation highlights relationships in this case study between competing claims about fringe greening and fringe landscape practices. These contests over the landscapes of the urban edge illustrate ways that municipal and regional planning visions for the urban edge conflict with the ideals and practices of those residents and land use managers who might otherwise be some of the strongest supporters of urban greening initiatives. Competing discourses about the urban edge relate in different ways to concerns about abrupt urban containment and to practices that act on these concerns. I briefly discuss promising examples of edge greening in this case that may provide models for participatory management of contested and multi-use greenspace at the urban–rural fringe.  相似文献   

20.
When an urban redevelopment project is planned, the design needs to reflect the preferences of the users of the planned space. In China, however, the preferences of residents have rarely been reflected in projects dealing with public places such as open green spaces in urban settings. This paper employs three independent conjoint analyses covering components of open green space, including locational conditions, physical conditions, and greenery conditions in order to propose the most preferable design for a new open green space. The results of choice simulation showed that the users prefer the private garden style to the general public park style for the new open green space in Dashilar. Our research with three independent conjoint analyses is expected to provide specific guidelines for open green space design as a whole, which is intended to satisfy potential users of the space.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号