Optimal harvesting time in single‐ and multiple‐purpose forest management

In single‐purpose timber producing forestry, the optimal harvesting time occurs when the net revenue on the stumpage value equals the cost of renting the land (the land‐use cost) minus the change in land value.

In multiple‐purpose forestry, the optimal time for harvesting occurs when the sum of the net revenues of the stumpage value and the amenity value is equal to the cost of renting the land minus the change in the land value. This land value is the sum of the land value for timber production and the land value for amenity services in the case of combined management of timber and amenity‐resources.     

Spatial optimization by simulated annealing and linear programming

Forest management planning comprises selection among treatment alternatives in management units. A traditional linear programming (LP) approach may effectively account for a profit maximization objective combined with sustainability constraints, e.g. on the temporal distribution of harvest volume flows, cash‐flow, and net present value development, but it fails to account for spatial constraints, especially those associated with final felling. By applying a simulated annealing adjacency model based on net present value maximization and combined with an LP consequence computation model, it is possible to delineate optimal strategies of final felling scheduling. Evaluation is made of the trade‐off between (1) the incremental cost (determined by use of the LP model) of an optimal adjacency model solution, and (2) the potential damage cost resulting from adjacency characteristics such as windthrow and bark injuries. The decision support system may contribute significantly to reduce damage costs and may improve the reliability of forest management planning.     

凉山雷波马湖莼菜资源的保护与开发利用

在调查雷波马湖莼菜原产地气候、水文等生态环境条件及种植现状的基础上,分析了雷波马湖莼菜开发利用的优势和存在的问题,雷波马湖莼菜资源拥有自然条件优越、品质优良、开发基础良好、开发潜力巨大等优势,也存在原生境退化、经济基础薄弱、规模低下、科研投入不足等问题,从完善监管体系、加强原生境保护、加大科研力度和科技示范带动等方面提出了推进雷波县马湖莼菜资源保护和开发利用的策略。     

坝上生态农业工程生态效益监测与评价研究

利用遥感技术、地理信息系统和全球定位系统对河北坝上实施生态农业工程建设后的生态效益进行了监测与评价。定量描述了坝上生态环境的动态变化趋势，并对坝上生态农业工程的气候效益、土壤改良效益、农业水文生态效益进行了分析与评价。研究结果表明，通过工程治理，使农业生态系统的功能增强，结构合理，取得了显著的生态效益。     

东北不同生态条件对大豆杂交后代的选择效应

以５个大豆杂交组合的Ｆ２－Ｆ５代为材料，连续４年在东北三省８个试验点按当地的高产育种目标进行选择，于Ｆ５代每个地点从每一组合中决选出１个高产品系，各地共计决选出４０个优良品系，并在上术８上地点以同一方案进行两年生态试验，以便分析生产条件对大豆杂交后代的选择效应。试验结果表明，在不同生态条件下，各地都选出了适合当地生态条件的生育期类型；在不同肥力条件下，各地都选出了适合当地生态条件的百粒重和抗倒伏性     

A Dynamic Model for Generation Expansion Planning and Algorithm

This paper discusses the problem of long-range generation expansion planning. A dynamic model for long-range expansion planning is set up and an algorithm-a two-step programming is presented, which is used here in a case.     

A Study on the Method of Time-Resource Optimization of Engineering Projects

This paper investigates the coordinated operation of the progress planning with the resource planning when carrying out engineering projects and puts forward a method of "RSM" under the resource limit conditions. Then, the "RSM" was improved to avoid complicated calculation. This method not only reduces the calculating work by hand but saves computer's memory as well, making the time-resource optimization work more quick and convenient.     

Developing the Regulatory Detailed Planning and Drawing up for Promoting the Urban Development--Some Ideas on Urban Construction of Middle and Small Cities in Underdevelopment Districts

This paper is directed against the traditional two-phase planning and drawing-up system widespread in the towns and cities of underdeveloped districts and suggests that the regulatory detailed planning and drawing up should be developed. During the planning and drawing up, the characteristic of town and city of underdeveloped districts should be taken into account and a choice and emphasis should be made for strengthening the urban planning administration and accelerating the urban development.     

Study on ES Based Generation System Planning

Based on the analysis of expert experience on generation system planning(GPS), the theory of knowledge based method is introduced into GPS to express the constraints of engineering(viz. Expert experience of engineering), and to discard abundant improper program during the earlier stage of GPS. In this situation, the difficulty degree of optimizing calculation in the later stage of GPS is lessened. And then, integrating expert system with production simulation in a method of GPS is proposed and is verified with an example. The results show that the method presented is effective.     

Producer services and growth management of a metropolitan region: the case of Kuala Lumpur,Malaysia

Producer services growth can change the character of a metropolitan region. Achieving that outcome may require the intervention of government, which is not necessarily a simple process as it creates tension between regulatory and developmental roles for government. This paper will address three interrelated issues in connection with the above-mentioned core idea in the context of the city of Kuala Lumpur, Malaysia: first, the extent to which the evolution of the Malaysian economy has been felt in the growth of the service sector; second, the way that evolution has led to change in the sectoral and spatial character of Kuala Lumpur; third, government’s responses in terms of spatial planning and management in order to accommodate producer services growth. The experience of the Kuala Lumpur region shows how global market forces and national development policies that influence producer service location and growth can reshape the spatial arrangement of a metropolitan region. Managing the growth of producer services calls for new approaches to manage metropolitan change. An ‘enabling’ model is proposed to replace the present ‘policing’ model of spatial planning.