Spatial optimization by simulated annealing and linear programming     

《Scandinavian Journal of Forest Research》2012,27(4):390-402

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.  相似文献   

机关企事业单位附属绿地规划设计研究     

蒋莉 《陕西林业科技》2012,(4):76-78

本文以城市绿地系统规划理论为基础,以陕西机关企事业单位的绿地规划为对象,探讨了公共事业庭院绿地规划设计的原则;公共事业庭院附属绿地典型区域规划设计的原则、方法与植物配置,为构建陕西事业单位绿地景观的可居、可行、可游、可赏提供决策依据。  相似文献   

泾惠渠水利风景旅游区总体规划设计     

冯静 《现代农业科技》2010,(10):373-374

通过分析和评价泾惠渠水利风景旅游区的旅游资源特征及价值,确定旅游区的性质、目标和规划原则,阐述了旅游区的规划布局、功能分区,并提出相关的规划建设建议和措施。  相似文献   

河北农业大学林学院发展现状及展望     

黄选瑞  郑建伟 《河北农业大学学报(农林教育版)》2012,14(5):84-87

10年以来,河北农业大学林学院在人才培养、科学研究、队伍建设、学术交流、社会服务等方面得到了长足的发展。除了学校的重视和政策支持,林学院将学科建设作为整个学院工作的核心,从学科方向整合到重点学科建设,采取了一系列措施。在河北农业大学建校110周年之际,回顾过去,总结经验,在学科专业建设、师资队伍建设、科研工作与服务能力建设、学术交流取得阶段性成就的基础上,积极谋划未来,切实树立特色铸校、人才强校、质量立校的理念,为建设特色鲜明的高水平区域性大学而努力奋斗。  相似文献   

关于新疆1∶100万农业地貌区划问题的讨论     

乔木  陈模 《干旱区研究》1995,12(2):54-57

根据新疆同一地貌区域形态成因，水热及农业发展方向和改造利用条件的相似性或不同地貌区间的差异性原则，建立起构造、新构造运动、外力作用，地貌形态等农业区划樗，以及农业地貌各级区域标志。  相似文献   

伊犁河流域地表水资源优势及开发利用潜力研究   总被引：3，自引：0，他引：3  

张军民 《干旱区资源与环境》2005,19(Z1):142-146

伊犁河流域是新疆地表水系最发达、径流最发育、水资源最丰富的内陆河流域,具有流域降水丰沛,径流补给充分,径流量大;水系发达,河川密布;水量变化较小、泥沙含量较少、水质较好的资源优势。但受经济发展水平及产业结构层次的限制,伊犁河流域水资源总体上仍处于利用效率低下、生产经营方式落后、综合利用潜力巨大的初级开发阶段。依据部颁SL201-9《江河流域规划编制规范》和流域整体规划目标,经过水资源多目标开发平衡分析与评价,给出了伊犁河流域水资源综合开发和合理配置远景规划方案。  相似文献   

Introduction   总被引：1，自引：0，他引：1  

Pedroli  Bas  Harms  Bert 《Landscape Ecology》2002,17(1):1-12

The realization of strategies for sustainable land use assumes specificresearch concepts from the local to the global scale (micro-, meso- andmacroscale). Therefore, landscape ecological science has to provideinvestigation methods for all these different scales. By combiningtop-down and bottom-up approaches in addition tocoupled GIS-model applications and traditional methods, the investigation oflandscape ecological structures and processes seems to be possible. Thepresented studies show this approach on examples of two study areas in EasternGermany: A watershed of 400 km² and an administrativedistrict of about 4000 km². The scale-specificapplicability of several models and methods were tested for theseinvestigations, and the validation of the calculated results are presented. Animportant outcome of the project should be the prevention of conflicts betweenagriculture, water management and soil, and water and nature conservation;based onrecommendations for land use variants with decreased pollutant loading withinagricultural areas. The scale specific investigations can be considered as abase for establishing sustainable land use.This revised version was published online in May 2005 with corrections to the Cover Date.  相似文献   

加速结构调整是大兴安岭可持续发展的必然     

谭俊 《内蒙古林业调查设计》2000,23(3):44-47

文章指出以“天保工程”为契机 ,以林业的持续发展为目的 ,调整大兴安岭林业生产结构 ,发挥其多功能互助的整体效益  相似文献   

COMPARISON OF ISODOSE DISTRIBUTIONS IN CANINE BRAIN IN HETEROGENEITY-CORRECTED VERSUS UNCORRECTED TREATMENT PLANS USING 6 MV PHOTONS     

J. LYONS  D.E. THRALL  A.F. PRUITT 《Veterinary radiology & ultrasound》2007,48(3):292-296

Magnetic resonance (MR) images may be useful for radiation planning due to greater contrast resolution. One disadvantage of MR images for radiation planning is the inability to incorporate electron density information into the dose calculation algorithm. To assess the magnitude of this problem, we evaluated radiation dose distribution in canine brain by comparing computed tomography (CT)-based radiotherapy plans with and without electron density correction. Computerized radiotherapy plans were generated for 13 dogs with brain tumors using 6 MV photons. A tissue-contouring program was used to outline the gross tumor volume (GTV) and the planning target volume (PTV) for each patient. Two treatment plans were generated for each dog. First, the plan was optimized without heterogeneity correction. Then the heterogeneity correction was implemented without changing any other plan parameters. Isodose distributions and dose volume histograms (DVHs) were used to compare the two plans. The D95 (dose delivered to 95% of the volume) within the PTV was calculated for each treatment plan and differences in the D95s were compared. The mean D95s without and with heterogeneity correction were 49.1 +/- 0.7 and 48.9 +/- 1.0Gy, respectively. The absolute mean percent dose difference without and with heterogeneity correction was 1.0 - 0.9% (-1.3-3.2%) and was not considered to be clinically significant. We found no clinically significant difference between CT-based radiotherapy plans without and with heterogeneity correction for brain tumors in small animals, which supports the use of MR-based treatment planning for radiotherapy of small animal brain tumors.  相似文献   

新世纪保护区面临的挑战及其有效对策   总被引：1，自引：0，他引：1  

王献溥  于顺利  陈宏伟 《野生动物》2006,27(4):6-9

道路、水库、建筑物、不断扩大的农田和土地退化正在使自然景观的完整性受到严重破坏。所保存的未经干扰或少受干扰的天然生态系统的面积日益缩小，犹如海洋中的孤岛。生物多样性受到严重的威胁。在自然保护区中，物种迁移和基因流动的可能性也在不断地降低。生物区域规划被认为是一种较好的选择，它力求把保护区和栽培地区视为一个有机整体，遵循保护和发展密切结合的方针，制定行动计划并予以实施。本文根据保护区的管理情况、工作条件和科研状况等，对保护区或区域的类型进行了划分，针对现实，提出了如何实施生物区域规划。  相似文献