我国银鱼研究概况及其移植的生态管理准则   总被引：4，自引：0，他引：4  

胡传林  刘家寿  彭建华  俞伏虎 《湖泊科学》2001,13(3):204-210

本文论述了我国银鱼的种类,分布,幼态持续现象,生态特性与移植增殖现状,并重点介绍了银鱼移植的生态管理准则－经济学准则,地理学准则,生物学准则和生态学准则。  相似文献   

Key principles of marine ecosystem-based management     

《Marine Policy》2015

Ecosystem-Based Management (EBM) has gained international popularity in recent years, but the lack of consensus on its definition has precluded the use of a universal implementation framework. The large number and variety of principles that make up EBM, and the diversity in perspectives among key management players, has impeded the practical application of EBM. Agreement on a list of the essential ingredients of EBM is vital to successful application. A frequency analysis of EBM principles was conducted to identify the Key Principles that currently define EBM, from a list of twenty-six principles extracted from a subset of the EBM theoretical/conceptual literature (covering a range of published sources across disciplines and application types). Fifteen Key Principles were identified (in descending frequency of appearance in the literature): Consider Ecosystem Connections, Appropriate Spatial & Temporal Scales, Adaptive Management, Use of Scientific Knowledge, Integrated Management, Stakeholder Involvement, Account for Dynamic Nature of Ecosystems, Ecological Integrity & Biodiversity, Sustainability, Recognise Coupled Social-Ecological Systems, Decisions reflect Societal Choice, Distinct Boundaries, Interdisciplinarity, Appropriate Monitoring, and Acknowledge Uncertainty. This paper also examines the development of EBM principles over time, leading to predictions on the directions EBM will take in the future. The frequency analysis methodology used here can be replicated to update the Key Principles of EBM in the future. Indeed, further research on potential emerging Key Principles such as ‘Consider Cumulative Impacts’, ‘Apply the Precautionary Approach’ and ‘Explicitly Acknowledge Trade Offs’ will help shape EBM and its successful application in the management of marine activities.  相似文献   

《激光原理与激光技术》课程建设与教学改革的实践探索     

钟先琼  胡晓飞  罗莉  侯俊勇  向安平 《成都信息工程学院学报》2009,24(4):422-426

根据在激光原理与激光技术课程建设和教学改革实践中的体会,从课程建设和教改的必要性、课程内容体系改革、教学手段和方法改革、课堂教学模式的探索和实践、大力培养学生科研意识和创新精神、完善课程考核模式等方面作了详细分析和阐述.  相似文献   

论我国地名的命名原则   总被引：3，自引：0，他引：3  

王际桐 《地球信息科学学报》2001,3(3):13-17

本文主要论述了从古至今地名命名的演变和命名原则、方法以及地名的命名规律。  相似文献   

Mapping beach morphodynamics remotely: A novel application tested on South African sandy shores     

Linda Harris  Ronel Nel  David Schoeman 《Estuarine, Coastal and Shelf Science》2011

Sandy beaches have been identified as threatened ecosystems but despite the need to conserve them, they have been generally overlooked. Systematic conservation planning (SCP) has emerged as an efficient method of selecting areas for conservation priority. However, SCP analyses require digital shapefiles of habitat and species diversity. Mapping these attributes for beaches from field data can take years and requires exhaustive resources. This study thus sought to derive a methodology to classify and map beach morphodynamic types from satellite imagery. Since beach morphodynamics is a strong predictor of macrofauna diversity, they could be considered a good surrogate for mapping beach biodiversity. A dataset was generated for 45 microtidal beaches (of known morphodynamic type) by measuring or coding for several physical characteristics from imagery acquired from Google Earth. Conditional inference trees revealed beach width to be the only factor that significantly predicted beach morphodynamic type, giving four categories: dissipative, dissipative-intermediate, intermediate and reflective. The derived model was tested by using it to predict the morphodynamic type of 28 other beaches of known classification. Model performance was good (75% prediction accuracy) but misclassifications occurred at the three breaks between the four categories. For beaches around these breaks, consideration of surf zone characteristics in addition to beach width ameliorated the misclassifications. The final methodology yielded a 93% prediction accuracy of beach morphodynamic type. Overlaying other considerations on this classification scheme could provide additional value to the layer, such that it also describes species’ spatial patterns. These could include: biogeographic regions, estuarine versus sandy beaches and short versus long beaches. The classification scheme was applied to the South African shoreline as a case study. The distribution of the beach morphodynamic types was partly influenced by geography. Most of the long, dissipative beaches are found along the west coast of the country, the south coast beaches are mostly dissipative-intermediate, and the east coast beaches range from short, estuarine pocket and embayed beaches in the former Transkei (south east), to longer intermediate and reflective beaches in KwaZulu-Natal (in the north east). Once combined with the three biogeographic regions, and distinguishing between estuarine and sandy shores, the South African coast comprised 24 different beach types. Representing shorelines in this form opens up potential for numerous spatial analyses that can not only further our understanding of sandy beach ecology at large spatial scales but also aid in deriving conservation strategies for this threatened ecosystem.  相似文献   

提高网络GIS效率的途径及其技术原理     

周京春  李黎 《地理空间信息》2011,(6):21-23,26

阻碍网络GIS性能的因素分为两大方面：硬件环境和软件环境。聚焦于软件环境,从通用网络GIS的三层体系架构上入手,分别在数据层、逻辑层和层间数据传输上描述了的一些可实施的优化途径及其技术原理,以综合应用来提高网络GIS的效率。  相似文献   

General Principles for Automated Generation of Schematic Network Maps   总被引：1，自引：0，他引：1  

Zhilin Li 《The Cartographic journal》2013,50(4):356-360

Usually, a street map contains various types of detailed information and appears to be crowded. As a result, to many users, a street map looks complicated and is not easy to read and follow. In fact, to a certain degree, too much detail makes the map uninformative and noisy. The London tube map, called a schematic or topological map in some literature, has often been cited as an excellent example of a simplified map. Algorithms have been developed by researchers to automate the generation of schematic maps for road networks. However, it is found that there is still a lack of defined general principles and here four general principles have been formulated for schematisation – the Principle of the Preservation of the Topological Relationship; the Principle of the Preservation of the Main Structure of the Line Network; the Principle of Relativity in Position; and the Principle of Relativity in Length. The first two are the principles of preservation: these two should never be violated. The last two are principles of relativity: it is very desirable to keep these two intact unless there is an absolute need to violate them.  相似文献   

Integrating general principles into mixed-integer programming to optimize schematic network maps     

Tian Lan 《International journal of geographical information science》2013,27(11):2305-2333

ABSTRACT

Schematic maps are popular for the representation of transport networks. Many automated methods have been developed to generate such maps. In these methods, optimization techniques work with various sets of constraints. Most of these constraints govern geometric properties of individual features. A few constraints address relationships among features, but none explicitly deal with the main structure of an entire network. We believe that preservation of main structure is the most important and preservation of relative relations is helpful. This is because human perception follows a global-to-local process. These constraints have recently been formed into four general principles, with two for global structure and two for relativity of features. This study develops an automated method by integrating these principles into the mixed-integer programming (MIP) framework. Experimental evaluations have been conducted with two sets of real-world transit networks. In comparison to the existing method, the proposed method has smaller fractal dimensions, better computational performance and higher scores in terms of clarity, recognition of major lines, visual simplicity and satisfaction. Therefore, it is concluded that the proposed method can generate schematic maps with improved clarity and aesthetics. The idea in this study is also helpful for the design of other visual representations.  相似文献   

A roadmap for marine spatial planning: A critical examination of the European Commission's guiding principles based on their application in the Clyde MSP Pilot Project     

Wesley Flannery  Micheál Ó Cinnéide 《Marine Policy》2012,36(1):265-271

The European Commission has developed a set of common principles for marine spatial planning in the European Union. A critical examination of these principles in practice is undertaken through an evaluation of the Clyde Marine Spatial Planning Pilot Project. The principles are found to be lacking in specificity and somewhat inconsistent with the ecosystem based approach, which they advocate. Lessons for new marine spatial planning initiatives, relating particularly to stakeholder participation, governance, data requirements, objective setting, and skills and knowledge needs, are derived from the Clyde Pilot.  相似文献   

经济地理学的九大原理   总被引：3，自引：1，他引：2  

梁进社 《地理研究》2008,27(1):75-84

经济地理学的理论通常针对其具体的研究对象,本文试图从这些理论中提炼出指导经济地理学家思考和分析,以及重复出现在这个学科中的要点。这些要点是最基本的,在经典的和现代的经济地理研究中具有普遍意义,而不仅仅是在当前或某些时段。本文称这些要点为原理,将它们归纳成包括区位选择与空间差异性、空间分析和区域政策等三个范畴共九大条。这些原理试图回答人们为什么、如何做区位选择以及它们之间的相互依存关系,概括关于空间经济的分析视角和途径,以及制定区域政策的经济地理学基础。认为这些原理的精炼在经济地理学的学术研究上有助于营造共同的语言,建立和提升大家比较认同的一般理论。在其应用研究上,有助于寻找和筛选重要的经济地理变量,建立分析框架和进行模型设计。  相似文献