期刊文献+
共找到24篇文章
< 1 2 >
每页显示 20 50 100
高速公路服务区系统服务水平综合评价方法 被引量:11
1
作者 赵君莉 汤毅 王建伟 《长安大学学报(自然科学版)》 EI CAS CSCD 北大核心 2008年第6期73-75,84,共4页
为了客观准确地评价高速公路服务区的服务水平,对高速公路服务区内各个功能设施的运行特性进行分析,并根据其运行特性提出了各个功能设施相应的服务水平分级指标、分级标准;采用距离综合评价法对多个服务区系统服务水平进行比较,得出其... 为了客观准确地评价高速公路服务区的服务水平,对高速公路服务区内各个功能设施的运行特性进行分析,并根据其运行特性提出了各个功能设施相应的服务水平分级指标、分级标准;采用距离综合评价法对多个服务区系统服务水平进行比较,得出其优劣次序,并结合重庆市4个服务区实测数据对该方法进行验证。结果表明,该评价方法能较好地反映高速公路服务区系统的服务水平,可减少人为因素的影响。 展开更多
关键词 交通工程 高速公路 服务区系统 服务水平 距离综合评价法
下载PDF
高速公路服务区系统服务水平评价方法研究 被引量:1
2
作者 赵君莉 汤毅 《商场现代化》 北大核心 2008年第33期165-166,共2页
本文主要从旅客的需求和主观感受出发,通过统计分析的方法得出服务区中各设施服务水平权重值,采用综合指数法对单个服务区系统服务水平进行了评价,确定了服务区系统服务水平等级,最后,采用重庆市四个服务区实测数据对评价方法进行了验证。
关键词 高速公路 服务区系统 指标权重 服务水平 评价方法
下载PDF
生态系统服务多功能区时空变化及其影响因素分析:以青藏高原生态屏障区为例
3
作者 李昊瑞 马帅 +2 位作者 殷允可 王良杰 姜姜 《生态与农村环境学报》 CAS CSCD 北大核心 2024年第8期1038-1046,共9页
生态功能分区是生态系统管理的重要环节,基于生态系统服务簇进行生态功能分区对维持生态系统的可持续性具有重要意义。以青藏高原生态屏障区为例,采用生态系统服务和权衡的综合评估模型(Integrated Valuation of Ecosystem Services and... 生态功能分区是生态系统管理的重要环节,基于生态系统服务簇进行生态功能分区对维持生态系统的可持续性具有重要意义。以青藏高原生态屏障区为例,采用生态系统服务和权衡的综合评估模型(Integrated Valuation of Ecosystem Services and Trade-offs,InVEST)、修正通用土壤流失方程模型(Revised Universal Soil Loss Equation,RUSLE)和卡内基-阿梅斯-斯坦福模型(Carnegie-Ames-Stanford Approach,CASA)评估产水量、土壤保持、固碳和生境质量,在县域尺度上基于主导的生态系统服务类型将研究区划分3个生态系统服务多功能区(生态调节多功能区E1、生态供给多功能区E2和生态支持多功能区E3),并分析了生态系统服务多功能区的时空变化及影响因素。结果表明:(1)与2000年相比,2015年青藏高原生态屏障区产水量和土壤保持减弱,固碳和生境质量提高;(2)青藏高原生态系统服务多功能区时空变化主要是E1和E3之间的相互转化;(3)降水是影响青藏高原生态系统服务多功能区空间格局形成的最主要因素,人口密度是增幅最明显的因素。社会经济因素和自然因素的共同作用加强了多功能区的相互转化。该研究结果可为青藏高原土地多功能属性的管理和国土空间整体功能的提升提供价值参考。 展开更多
关键词 生态系统服务多功能 时空变化 影响因素 青藏高原 生态屏障
下载PDF
基于极致梯度提升和支持向量机的高速公路服务区供暖系统健康状态评估 被引量:1
4
作者 王强 贺晓宇 +1 位作者 刘文辉 赵建东 《交通节能与环保》 2023年第3期153-158,共6页
为保障高速公路服务区供暖系统的健康运行,本文结合供暖系统的构成和运行特征,设计了一种用于评估服务区供暖系统运行健康状态的极致梯度提升(Extreme Gradient Boosting,XGBoost)和支持向量机(Support Vector Machine,SVM)的双层机器... 为保障高速公路服务区供暖系统的健康运行,本文结合供暖系统的构成和运行特征,设计了一种用于评估服务区供暖系统运行健康状态的极致梯度提升(Extreme Gradient Boosting,XGBoost)和支持向量机(Support Vector Machine,SVM)的双层机器学习模型,并将系统运行健康状态分为健康、亚健康、故障和异常四个等级。首先,分析电压、电流、水温、机组运行状态、蓄热泵、循环泵和泵运行状态7个子系统的运行特征,使用随机函数和欠采样处理构建特征向量集。其次,采用XGBoost构建下层各子系统健康状态评估模型,并输出各子系统的健康状态。然后,融合各子系统健康状态的评估结果,输入至上层SVM系统评估模型,得到整个供暖系统的健康状态。最后,将实验与决策树、AdaBoost和XGBoost等模型进行对比,结果表明所提出的XGBoost+SVM双层机器学习模型相较对比模型而言,不仅判断精度更高,同时还可评估整个供暖系统以及各子系统的健康状态。 展开更多
关键词 运输规划与管理 双层机器学习模型 极致梯度提升 支持向量机模型 服务供暖系统 数据特征
下载PDF
基于双层支持向量机的污水处理系统健康状态评估 被引量:3
5
作者 刘文辉 贺晓宇 +2 位作者 罗二娟 岳丛俊 赵建东 《科学技术与工程》 北大核心 2022年第29期13090-13095,共6页
为有效保障高速公路服务区污水处理系统的健康运行,结合污水处理系统的构成和系统运行特征,设计了一种用于评估污水处理系统健康状态的双层支持向量机(support vector machine, SVM)模型,并将健康状态分为健康、亚健康、故障和异常4个... 为有效保障高速公路服务区污水处理系统的健康运行,结合污水处理系统的构成和系统运行特征,设计了一种用于评估污水处理系统健康状态的双层支持向量机(support vector machine, SVM)模型,并将健康状态分为健康、亚健康、故障和异常4个等级。首先,分析提升泵、进水泵、自吸泵等6个子系统的运行特征,使用随机函数和欠采样处理构建特征向量集。其次,采用SVM构建下层各子系统健康状态评估模型,并使用ThunderSVM算法来提高模型训练速度。再次,融合下层各子系统健康状态评估的结果,构建上层SVM系统评估模型,得到整个污水处理系统的健康状态。最后,依据青兰高速山西段服务区污水处理系统进行验证。结果表明,所提出的双层SVM模型相较树类模型和单层SVM模型不仅可评估整个污水处理系统的健康状态,还可评估各子系统的健康状态,且模型训练速度和判断精度均有提升。 展开更多
关键词 系统健康状态 双层支持向量机模型 服务污水处理系统 数据特征
下载PDF
A Self-organization Mapping Neural Network Algorithm and Its Application to Identify Ecosystem Service Zones 被引量:16
6
作者 战金艳 史娜娜 +1 位作者 吴红 邓祥征 《Agricultural Science & Technology》 CAS 2009年第5期162-165,共4页
The self-organization mapping (SOM) neural network algorithm is a new method used to identify the ecosystem service zones at regional extent. According to the ecosystem assessment framework of Millennium Ecosystem A... The self-organization mapping (SOM) neural network algorithm is a new method used to identify the ecosystem service zones at regional extent. According to the ecosystem assessment framework of Millennium Ecosystem Assessment ( MA), this paper develops an indicator system and conducts a spatial cluster analysis at the 1km by I km grid pixel scale with the SOM neural network algorithm to sort the core ecosystem services over the vertical and horizontal dimensions. A case study was carried out in Xilingol League. The ecosystem services in Xilingol League could be divided to six different ecological zones. The SOM neural network algorithm was capable of identifying the similarities among the input data automatically. The research provides both spatially and temporally valuable information targeted sustainable ecosystem management for decision-makers. 展开更多
关键词 Neural network algorithm Ecosystem services Ecosystem service zones Sustainable ecosystem management
下载PDF
Assessment of Ecosystem Services Value in Hotan Oasis, Xingjiang 被引量:3
7
作者 杨依天 王平 +2 位作者 黄宇 张月从 郭翠恩 《Agricultural Science & Technology》 CAS 2013年第3期425-432,共8页
[Objective] The study aimed to assess the ecosystem services value in Hotan Oasis, Xingjiang. [Method] The visual interpretation method was adopted to process TM/ETM+ images based on field investigation in Hotan Oasi... [Objective] The study aimed to assess the ecosystem services value in Hotan Oasis, Xingjiang. [Method] The visual interpretation method was adopted to process TM/ETM+ images based on field investigation in Hotan Oasis. These inter- pretation data, along with two periods of land use data, were reclassified to farm- land, forest, grassland and so on. Then, the ecosystem services value was calculat- ed and analyzed. [Result] Analysis indicated that the ecosystem services value had been increased by 30.44x108 Yuan (16.51%) in the study area during 1980-2010, which can be explained by the increase of glacier and snowfield distributed in the south mountain with the increase of annual precipitation. At the same time, the con- tribution rate of grassland to ecosystem services value had been decreased as a result of degradation of grassland and occupation from farmland. For the whole basin, the increase of ecosystem services value came from the upper reaches, while the ecosystem services value had been reduced in the middle and lower reaches. In the middle reaches, the reduction came mainly from wetland (-1.83x10s Yuan), waters (-1.68x10s Yuan), forest (-0.86x108 Yuan) and grassland (-0.80x108 Yuan). But in the lower reaches, the ecosystem services values of waters, grassland and forest were -0.61 x108 Yuan, -0.24x108 Yuan, and -0.07x10s Yuan, respectively. [Conclusion] If some effective policies, such as the implementation of returning farm- land to forest and ceasing from farming to grazing, would be taken, the ecosystem degradation can be constrained and reversed in the northwest arid region. 展开更多
关键词 Arid region Ecosystem services value ASSESSMENT Hotan Oasis
下载PDF
Effects of Land Use Change on Ecosystem Services in Arid Area Ecological Migration 被引量:9
8
作者 LIU Xiaopeng CHEN Xiao +5 位作者 HUA Kaiping WANG Yajuan WANG Peng HAN Xiaojia YE Junyan WEN Shengqiang 《Chinese Geographical Science》 SCIE CSCD 2018年第5期894-906,共13页
Ecological migration is the process of increasing the population density in the immigration area and transferring the ecological pressure from emigration area to immigration area. This process may result in significan... Ecological migration is the process of increasing the population density in the immigration area and transferring the ecological pressure from emigration area to immigration area. This process may result in significant changes in land use and land cover in the area of immigration and have an important effect on ecosystem services. Therefore, scientifically revealing the effects and differentiation mechanisms of ecological migration on ecosystem services is becoming an important issue related to the implementation of the national ecological migration strategy in China. This study employed the Hongsibu District as a typical example of ecological migration. Hongsibu District is located in the central Ningxia steppe and desert steppe areas. Remote sensing data covering five periods from the period before ecological migration in 1995 and after migration in 2000, 2005, 2010, and 2015 was used to measure the value of ecosystem services(ESV). A geographical detector model and the value of ecosystem services model were used to diagnose the dynamic mechanism of the effects of land use change on ecosystem services. The results showed that: 1) The development of large-scale ecological resettlement has caused the area of cultivated land and urbanized land area to increase significantly in the area of immigration, while the grass area decreased significantly. 2) The overall value of the Hongsibu ecosystem services increased in a form of a ‘V'. Among them, during the period of 1995–2005, the overall ESV decreased and had an annual rate of change of-0.67%. During the period of development 2005–2015, the ESV increased steadily, with an annual rate of change of 0.79%. 3) The proportion and total ESV in soil formation and protection, waste treatment, and biodiversity conservation of the Hongsibu District decreased from 57.61% in 1995 to 56.17% in 2015, indicating that the region's ecological regulation function slightly decreased. 4) The ESV in the Hongsibu District, showed a low distribution pattern of ecosystem services increasing from northeast to southwest, and the capacity of three townships, Hongsibu, Taiyangshan, and Liuquan, to provide ecosystem services gradually declined over time. The ecological service function of Xinzhuangji Township and Dahe Township gradually improved. 5) The sensitivity index of the ESV of each land use type was less than 1, indicating that the environment lacks flexibility in providing a strong ESV index in Hongsibu, which shows that the research results are reliable and believable. 6) During the study period, the decisive force of the change of land use on ecosystem services in Hongsibu District was: grassland(0.9934), climate regulation(0.9413), soil formation and protection(0.9321) and waste treatment(0.9241). 展开更多
关键词 ecological migration land use change ecosystem services geo-detector arid area Hongsibu district
下载PDF
Effects of Crude Oil Contamination on Soil Physical and Chemical Properties in Momoge Wetland of China 被引量:12
9
作者 WANG Ying FENG Jiang +3 位作者 LIN Qianxin LYU Xianguo WANG Xiaoyu WANG Guoping 《Chinese Geographical Science》 SCIE CSCD 2013年第6期708-715,共8页
Large oilfields are often coincidentally located in major river deltas and wetlands,and potentially damage the structure,function and ecosystem service values of wetlands during oil exploration.In the present study,th... Large oilfields are often coincidentally located in major river deltas and wetlands,and potentially damage the structure,function and ecosystem service values of wetlands during oil exploration.In the present study,the effects of crude oil contamination during oil exploration on soil physical and chemical properties were investigated in marshes of the Momoge National Nature Reserve in Jilin Province,China.The concentrations of total petroleum hydrocarbons in the marsh soil near the oil wells are significantly higher than those in the adjacent control marsh.Soil water contents in oil-contaminated marshes are negatively correlated with soil temperature and are significantly lower than those in the control area,especially in fall.Crude oil contamination significantly increases the soil pH up to8.0,and reduces available phosphorus concentrations in the soil.The concentrations of total organic carbon are significantly different among sampling sites.Therefore,crude oil contamination could potentially alkalinize marsh soils,adversely affect soil fertility and physical properties,and cause deterioration of the marshes in the Momoge National Nature Reserve.Phyto-remediation by planting Calamagrostis angustifolia has the potential to simultaneously restore and remediate the petroleum hydrocarbon-contaminated wetlands.Crude oil contamination affects the soil physical and chemical properties,so developing an effective restoration program in the Momoge wetland is neccesary. 展开更多
关键词 crude oil contamination marsh soil oilfield in marshes soil physical and chemical properties WETLAND Momoge National Nature Reserve
下载PDF
Communication Service Model for Wide Area Protection System Based on IEC 61850
10
作者 丛伟 潘贞存 +2 位作者 高湛军 曾煜晓 翟运娟 《Transactions of Tianjin University》 EI CAS 2008年第3期226-230,共5页
In order to meet the requirements of information exchange varieties and manners in wide area protection system, a communication service model based on IEC 61850 is proposed. This service model can realize communicatio... In order to meet the requirements of information exchange varieties and manners in wide area protection system, a communication service model based on IEC 61850 is proposed. This service model can realize communication consistency and cooperation between different types of devices. Furthermore, the communication reliability and time delay performance are guaranteed to meet the requirements of relay protection from the upper layer. Message structure of generic sub-station event (GSE) and its communication mechanism are discussed. General methods to communicate digital information by generic substation status event (GSSE) and communicate analog sampling information by sampling analog value (SAV) of GSE are proposed. 展开更多
关键词 wide area protection IEC 61850 COMMUNICATION service model
下载PDF
Hydrological Services by Mountain Ecosystems in Qilian Mountain of China: A Review 被引量:6
11
作者 SUN Feixiang LYU Yihe +1 位作者 FU Bojie HU Jian 《Chinese Geographical Science》 SCIE CSCD 2016年第2期174-187,共14页
Hydrological service is a hot issue in the current researches of ecosystem service, particularly in the upper reaches of mountain rivers in dry land areas, where the Qilian Mountain is a representative one. The Qilian... Hydrological service is a hot issue in the current researches of ecosystem service, particularly in the upper reaches of mountain rivers in dry land areas, where the Qilian Mountain is a representative one. The Qilian Mountain, where forest, shrubland and grassland consist of its main ecosystems, can provide fresh water and many other ecosystem services, through a series of eco-hydrological process such as precipitation interception, soil water storage, and fresh water provision. Thus, monitoring water regulation and assessing the hydrological service of the Qilian Mountain are meaningful and helpful for the healthy development of the lower reaches of arid and semi-arid areas. In recent 10 years, hydrological services have been widely researched in terms of scale and landscape pattern, including water conservation, hydrological responses to afforestation and their ecological effects. This study, after analyzing lots of current models and applications of geographical information system(GIS) in hydrological services, gave a scientific and reasonable evaluation of mountain ecosystem in eco-hydrological services, by employing the combination of international forefronts and contentious issues into the Qilian Mountain. Assessments of hydrological services at regional or larger scales are limited compared with studies within watershed scale in the Qilian Mountain. In our evaluation results of forest ecosystems, it is concluded that long-term observation and dynamic monitoring of different types of ecosystem are indispensable, and the hydrological services and the potential variation in water supplement on regional and large scales should be central issues in the future research.v 展开更多
关键词 hydrological service water regulation hydrological response Qilian Mountain
下载PDF
Climate change impact in the Western Himalaya:people's perception and adaptive strategies 被引量:2
12
作者 Vikram S.Negi Rakesh K.Maikhuri +2 位作者 Dalbeer Pharswan Shinny Thakur Pitamber P.Dhyani 《Journal of Mountain Science》 SCIE CSCD 2017年第2期403-416,共14页
The Himalaya represents a vast mountain system and globally valued for its significant role in regulation of global as well as regional climate that has direct impact on biodiversity and ecosystem services crucial for... The Himalaya represents a vast mountain system and globally valued for its significant role in regulation of global as well as regional climate that has direct impact on biodiversity and ecosystem services crucial for sustenance of millions of people in Himalaya and adjoining areas. However, mountain regions worldwide are impacted by climate change and at the same time represent distinctive area for the assessment of climate related impacts. Climate change impacts in Himalayan region have its implications on food production, natural ecosystems,retreat of glacier, water supply, human and animal health and overall human well being. The livelihood and food security of the people inhabited in region largely depend on climate sensitive sectors i.e.agriculture, livestock, forestry and their interlinkages with each other, and has the potential to break down food and nutritional security as well as livelihood support systems. People's perception and understanding of climate can be an important asset when it comes to adaptation to climate change impact;however it is not taken into consideration for the development of policy design and implementation of modern mitigation and adaptation strategies by governments and other civil society organizations.The knowledge of local people and farming communities for rural landscape management and sustainable use of bioresources is gaining credence as a key strategy to cope up with the climate change.Therefore, the present study analyzes the indigenous knowledge of local people and their perceptions on climate change, and also documented adaptation approaches at local level in mountain ecosystem of western Himalaya. The study could be useful to policy makers to design appropriate adaptation strategies to cope up with the impacts of climate change. 展开更多
关键词 Western Himalaya Climate change People's perception Traditional knowledge ADAPTATION
下载PDF
Volunteer Activities in Time of Disaster in Japan's Highly Information-Oriented Society
13
作者 Kayoko Yamamoto 《Journal of Earth Science and Engineering》 2013年第3期190-202,共13页
This study aims to clarify the characteristics of volunteer activities in times of disaster, while taking into account the influence of the orientation towards information intensity, which is an important feature of c... This study aims to clarify the characteristics of volunteer activities in times of disaster, while taking into account the influence of the orientation towards information intensity, which is an important feature of contemporary Japanese society, and focusing on the volunteer activities for recovery and reconstruction in the disaster-stricken areas of the Great East Japan Earthquake. In modern Japanese society, because volunteer activities are being conducted in a variety of forms, those who wish to volunteer can participate in volunteer activities that suit their own situation. Further, in a highly information-oriented society such as modern Japan, many kinds of information systems can be used to conduct a variety of volunteer activities. Also, know-how concerning the introduction and methods of volunteer activity and recruitment for participants in volunteer activities are introduced using various information media, and there are many volunteer activities to choose from. Therefore, it is possible that through the diversification of volunteer activities, many people become involved in volunteer activities on a long-term basis, using ways of doing so that are possible for themselves. 展开更多
关键词 Volunteer activity DISASTER highly information-oriented society information systems GIS (geographic information systems) Great East Japan Earthquake.
下载PDF
Changes in Ecosystem Service of Soil Conservation Between 2000 and 2010 and Its Driving Factors in Southwestern China 被引量:17
14
作者 RAO Enming XIAO Yi +1 位作者 OUYANG Zhiyun ZHENG Hua 《Chinese Geographical Science》 SCIE CSCD 2016年第2期165-173,共9页
Human activities significantly alter ecosystems and their services; however, quantifying the impact of human activities on ecosystems has been a great challenge in ecosystem management. We used the Universal Soil Loss... Human activities significantly alter ecosystems and their services; however, quantifying the impact of human activities on ecosystems has been a great challenge in ecosystem management. We used the Universal Soil Loss Equation and county-level socioeconomic data to assess the changes in the ecosystem service of soil conservation between 2000 and 2010, and to analyze its spatial characteristics and driving factors in the southwestern China. The results showed that cropland in the southwestern China decreased by 3.74%, while urban land, forest, and grassland areas increased by 46.78%, 0.86%, and 1.12%, respectively. The soil conservation increased by 1.88 × 10^(11) kg, with deterioration only in some local areas. The improved and the degraded areas accounted for 6.41% and 2.44% of the total land area, respectively. Implementation of the Sloping Land Conversion Program and urbanization explained 57.80% and 23.90% of the variation in the soil conservation change, respectively, and were found to be the main factors enhancing soil conservation. The 2008 Wenchuan earthquake was one of the factors that led to the degradation of soil conservation. Furthermore, industrial adjustment, by increasing shares of Industry and Service and reducing those of Agriculture, has also promoted soil conservation. Our results quantitatively showed and emphasized the contributions to soil conservation improvement made by implementing ecological restoration programs and promoting urbanization. Consequently, these results provide basic information to improve our understanding of the effects of ecological restoration programs, and help guide future sustainable urban development and regional industrial restructuring. 展开更多
关键词 soil conservation ecosystem service Sloping Land Conversion Program(SLCP) ecological restoration urbanization southwestern China
下载PDF
Regulating services in poverty ecosystems dynamics: evidences from South Asia
15
作者 Pushpam KUMAR 《Ecological Economy》 2010年第1期31-44,共14页
Valuation of ecosystem services has been sought as effective tools that enable the decision makers in designing the cost effective response policies for management of ecosystems towards alleviating the poverty especia... Valuation of ecosystem services has been sought as effective tools that enable the decision makers in designing the cost effective response policies for management of ecosystems towards alleviating the poverty especially in economically poor regions like South Asia. Various directions and linkages between poverty and degradation of ecosystem and reduced flow of ecosystem services can better be understood if the regulating services like hydrological flow and carbon sequestration by forest, and nutrient cycling and bioremediation: by wetlandv can be captured in monetary unit. South Asian Countries including India. Nepal, Pakistan and Bangladesh are the hotspots of poverty where poor depend upon various ecosystem services for their livelihoods and allocation of resource for conservation of ecosystems would have additional merit if regulating services are captured and internalized into the pubtic policy.The paperfirst raises problematic issues in valuation of regulatig ecosystem services, and attempts to link it withthe dependence of poor. Second, complexities of poverty-ecosystem dynamics are discussed. Thirdly, the possible in-tervention to achieve poverty alleviation goal is analyzed with the help of some examples from accounting and valua-tion of regulating services of lndian forest. Finally, the paper suggests that greater attention is needed to do credibleand better valuation of regulating Services so that insight from these ean be used in understanding the impact of degradation of ecosysterns On poor people. 展开更多
关键词 VALUATION Regulating services Poverty-ecosystem-linkages
下载PDF
Nutritional Contribution Model of Litterfall for Adjacent Areas According to the Distance of Forest
16
作者 Thomaz Costa Leon Costa Leticia Almeida 《Journal of Environmental Science and Engineering(A)》 2017年第7期346-362,共17页
The goal of this study is to evaluate the drift of litterfall from forest to adjacent areas, validate a method to estimate the drift with water balance, direction and speed of winds and quantify the nutrients of litte... The goal of this study is to evaluate the drift of litterfall from forest to adjacent areas, validate a method to estimate the drift with water balance, direction and speed of winds and quantify the nutrients of litterfall in nearby area of the forest patch as function of distance. This phenomenon can be considered an ecosystem service to improve soil quality of the agriculture crops around the forests by nutrient input coming from the litterfall. The experiment was installed in adjacent areas of the tropical forest at central region of the State of Minas Gerais, Brazil. The branches, reproductive material and leaves which fell were measured for three years into the forest and adjacents areas. The sampled nets were located on edge and equal distances from the edge. It's analyzed and estimated the contribution of the litterfall components to adjacent areas by air. The quantity of litterfall by distance had large variation between adjacent areas. And it was confirmed that model estimated the leaf drift by distance with good precision. 展开更多
关键词 Wind analyze modelling ecosystem service.
下载PDF
Uses of Invasive Alien Plant Species in Rema-Kalenga Wildlife Sanctuary of Bangladesh
17
作者 Md.Parvez Rana Fahima Akhter 《Journal of Mountain Science》 SCIE CSCD 2010年第4期380-385,共6页
An exploratory survey was conducted on the uses and role of invasive alien species(IAS) to local livelihoods in the Rema-Kalenga Wildlife Sanctuary in the northeastern hilly region of Bangladesh.Vegetation was sampled... An exploratory survey was conducted on the uses and role of invasive alien species(IAS) to local livelihoods in the Rema-Kalenga Wildlife Sanctuary in the northeastern hilly region of Bangladesh.Vegetation was sampled in 50 quadrates,each 10 m×10 m,and 25 line transects,each 50 m×20 m,through a combination of random and systematic sampling.Group discussions were also arranged with fifty local inhabitants(17 % of the total inhabitants) to learn the various uses of IAS.A total of 17 alien plant species belonging to 10 different families,of which Leguminosae constitutes the highest number(5 species),include tree(53%) followed by herb(12%),shrub(12%) and others(weed,climber and palm).The majority of the identified species were found to be used for fuel,followed by timber production,medicinal or curative uses,fodder,and many others.In addition to providing various forest products,alien tree species planted in forest plantation help provide many vital ecosystem services such as soil amelioration through nitrogen fixation.It is true that the alien species have some negative impacts on local ecosystems,and not all of them are harmful.Therefore,a national programme must be initiated to distinguish the harmful from the harmless species and to identify the uses and impacts of the former and latter. 展开更多
关键词 Invasive alien species BIODIVERSITY Livelihoods Rema-Kalenga Wildlife sanctuary BANGLADESH
下载PDF
Integrated Approach to the Formation of Service Areas for Urban Substations of Different Voltage
18
作者 Nataly Skobeleva Oleg Borscevskis Svetlana Guseva Lubov Petrichenko 《Journal of Energy and Power Engineering》 2012年第8期1358-1362,共5页
UPSS (urban power supply system) is a part of the region or the state power supply system. UPSS development is closely connected with region power supply system development as a whole. The decision of questions of l... UPSS (urban power supply system) is a part of the region or the state power supply system. UPSS development is closely connected with region power supply system development as a whole. The decision of questions of long-term and middle-term planning of UPSS development occurs in the conditions of incompleteness and uncertainty of the initial information. Nevertheless in these conditions the acceptance of development strategy should be based on perspective electric loads of urban TS (transformer substations). There are difficulties with a rational placement of substations in the city with the developed infrastructure. Such problem by theoretically grounded approach to rational formation of UPSS is solved. The hierarchical structure of the organizational construction, voltage levels and load densities is considered. The mathematical and geometrical modeling of service areas for transformer substations of different voltage is fulfilled. The method of graphic placement of transformer substations in the city territory for new substations at existing structure of networks is offered. The aim of the work is to present the new uniform approach which allows finding a rational decision for new substations' placement in cities with developed infrastructure on the beginning design stages in conditions of the information uncertainty. The calculation program Microsoft EXCEL and the graphic program AutoCAD are used for realization of method. 展开更多
关键词 Power system load density voltage level urban substations.
下载PDF
Research on the Construction of Intelligence Community Integrated Information Service platform
19
作者 Tengfei Zhang Junhui Fan Jun Hu 《International English Education Research》 2015年第5期107-108,共2页
With the constructions of "intelligence city", intelligent life quietly came to the people. As the "cell" of the city, the construction of intelligence community arises. Resident service system and e-government ap... With the constructions of "intelligence city", intelligent life quietly came to the people. As the "cell" of the city, the construction of intelligence community arises. Resident service system and e-government application system have been used in the traditional information community, but these systems are independent of each other, lack of interconnectedness, which results in the phenomenon of information isolated island. Intelligence community integrated information service platform can integrate information service resources and provide residents with efficient and convenient life. From the meaning, operation mode, we can design the cooperative, open and extensible system architecture. 展开更多
关键词 smart community integrated information service platform system architecture ctc.
下载PDF
Design of Remote Control System of Intelligent Community Based on Embedded Web Server
20
作者 Fenfen Cheng 《International Journal of Technology Management》 2013年第3期66-68,共3页
A multichannel remote control system for imelligent community based on the STC89C54 chip was designed with the technique of embedded Web server. The control system can monitor 255 signals and eight control signals of ... A multichannel remote control system for imelligent community based on the STC89C54 chip was designed with the technique of embedded Web server. The control system can monitor 255 signals and eight control signals of one node at the same time, and can be connected to the internet by the TCP/IP protocol. So the field control information can be shown dynamically in a remote computer by way of web pages. The system has high convenience and friendly monitoring interface, then especially is fit for the large conamunity and storage that need multipoint monitoring and frequent switching door. 展开更多
关键词 Intelligent Community control Embedded Web server MULTICHANNEL STC89C54 Hall sensor CS1013
下载PDF
上一页 1 2 下一页 到第
使用帮助 返回顶部