Finding shortest paths in the plane in the presence of barriers to travel (for any lp - norm)

This paper develops an efficient algorithm for the computation of the shortest paths between given sets of points (origins and destinations) in the plane, when these paths are constrained not to cross any of a finite set of polygonal (open or closed) barriers. It is proved that when distances are measured by an 1_p - norm with 1 < p < ∞, these paths are formed by sequences straight line segments whose intermediate (e.g. apart from origin and destination) end points are barrier vertices. Moreover, only segments that locally support the barriers to which their end points belong are elligible for inclusion in a shortest path. The special case of one origin and one destination is considered, as well as the more general case of many origins and destinations. If n is the number of nodes (origins, destinations and barrier vertices), an algorithm is presented that builds that network of all shortest paths in O(n² log n) time. If the total number of edges in this network is e (bounded by n²), the application of Dijkstra's algorithm enables this computation of the shortest paths from any origin to all destinations in O(e log n) time. If the origins, shortest paths from all origins to all destinations can thus be found in O(ne log n) ≤ O(n^{3 log n}) time.It is also shown that optimal solutions when distances are measured according to the rectilinear or max-norm (i.e. l_p-norm with p = 1 or p = ∞) can be deduced from the results of the algorithm.     

Load balancing optimization of telecommunication networks with two differentiated services

The Differentiated Services architecture is a scalable solution to provide differentiated Quality of Service. In this paper, we address the network load balancing optimization of such networks based on bandwidth differentiation between two services. We define the optimization problem as an Integer Programming model and propose a heuristic algorithm based on GRASP with Path Relinking. We present computational results showing that (i) good quality solutions can be computed and (ii) proper load balancing can efficiently obtain service differentiation.     

湖南生产服务业与先进装备制造业产业发展关系研究

以投入产出模型为基础,计算出湖南省生产服务业与先进装备制造业这两行业与各分行业的直接消耗系数、完全消耗系数、感应度系数和影响力系数.研究表明：先进装备制造业消耗力度大于生产服务业,但二者消耗水平均远低于发达国家,先进装备制造业对生产服务业的需求推动力和影响力较强,生产服务业的传统服务部门对产业发展推力较强,但资本、知识密集型生产服务部门作用正日益凸显,创新型部门则有待进一步发展.基于上述结论,提出了以生产服务业促进先进装备制造业发展,以先进装备制造业推动生产服务业发展的政策建议.     

Cost-Effective Migration from Sub-Lambda to Wavelength-Based Metro Networks

This article will discuss the importance of hybrid coexistence of sub-lambda grooming with wavelength-based services for driving down costs and maximizing the use of metro bandwidth, as well as enabling next-generation lambda-based services. The article will also address migration to all optical metro networks.     

Consortium GARR and the European National Research and Education Networks Optical Infrastructure Developments

Abstract

GARR is engineering its next generation of the Italian Research and Education Network (GARR-X), which will exploit a countrywide optical infrastructure based on DWDM equipment and advanced multi-domain services. The trend is common in all National Research and Education Networks [1 TERENA NREN Compendium. http://www.terena.org/activities/compendium ISSN 1569-4496 [Google Scholar]] in Europe and worldwide. NRENs are relying more and more on direct use of optical equipment to fulfill the researchers' requirements. These hybrid networks are built to provide services on a multi-domain environment both at the circuit and at the IP layer for researchers in, for example, radio astronomy (eVLBI [2 European Very Long Baseline Interferometry http://www.evlbi.org [Google Scholar]]), GRID computing (EGEE [3 Enabling Grids for E-sciencE http://public.eu-egee.org [Google Scholar]], LHC [4 The Large Hadron Collider http://lhc.web.cern.ch/lhc [Google Scholar]]), high-performance computing (DEISA [5 The Distributed European Infrastructure for Supercomputing Applications http://www.deisa.org [Google Scholar]]). This article outlines the status and issues of ongoing research activities in GARR [6 http://www.garr.it/garr-b-home-engl.shtmlConsortium GARR, the Italian NREN [Google Scholar]] and NRENs to provide, manage, and evolve dedicated optical-based networks for providing multi-domain end-to-end services. The research is performed mainly in the framework of the European Commission co-funded project GÉANT2 [7 The pan-European R&E network http://www.geant2.net [Google Scholar]].     

Optimizing specimen collection for processing in clinical testing laboratories

We study the logistics of specimen collection for a clinical testing laboratory that serves sites dispersed in an urban area. The specimens that accumulate at the customer sites throughout the working day are transported to the laboratory for processing. The problem is to construct and schedule a series of tours to collect the accumulated specimens from the sites throughout the day. Two hierarchical objectives are considered: (i) maximizing the amount of specimens processed by the next morning, and (ii) minimizing the daily transportation cost. We show that the problem is NP-hard and formulate a linear Mixed Integer Programming (MIP) model to solve the bicriteria problem in two levels. We characterize properties of optimal solutions and develop a heuristic approach based on solving the MIP model with additional constraints that seeks for feasible solutions with specific characteristics. To evaluate the performance of this approach, we provide an upper bounding scheme on the daily processed amount, and develop two relaxed MIP models to generate lower bounds on the daily transportation cost. The effectiveness of the proposed solution approach is evaluated using realistic problem instances. Insights on key problem parameters and their effects on the solutions are extracted by further experiments.     

杭州城市土地类型与自然区划

杭州城市土地类型分为院落(Yard)、地段(Secicon)和地方(Land svsiem)三级.根据土地地方类型结构,将杭州市区划分为九个自然区     

卢瑟福散射与原子的有核模型

回顾了卢瑟福散射实验,并从原子的有核模型的建立引出一些思考。     

东海区海岸带景观格局变化对生态系统服务价值的影响

对大尺度、长时序的海岸带景观格局和生态系统服务价值(ecosystem services value,ESV)的研究,有利于更好地促进区域生态系统保护工作的开展。以1990,1995,2000,2005,2010,2015年6期遥感影像解译结果为基础,对东海区海岸带景观格局变化特征和ESV时空演变进行了分析,并探讨了ESV与景观格局变化二者间的关系。结果表明,1990—2015年的25 a间,受人类活动的影响,东海区海岸带农田和海域面积大量减少,建设用地面积大幅增加;在所研究的5类地貌类型中,除中起伏山地外,其余地貌类型景观面积转移都较为剧烈。25 a间东海区海岸带斑块数量、斑块密度、边界密度、shannon多样性指数等不断增加,景观破碎化、复杂化、多样化增强。农田景观的最大斑块指数、形态指数、边界密度等变化均较大。东海区海岸带ESV呈先增加后减小的趋势,其中森林景观对ESV总量贡献最大;水文调节、生物多样性维持、气候调节、土壤保持、废物处理和气体调节是东海区海岸带主要的生态系统服务功能;在空间上表现出以单位面积中、低ESV为主导的空间分布,高、极高和极低ESV分布较少。研究区ESV总量与农田和海域以及水域和建设用地面积显著相关;与斑块密度、边界密度和形态指数呈显著负相关。同时,食物生产、气体调节、气候调节、土壤保持和生物多样性维持的服务价值与景观指数间均显著相关。     

地理学与海洋学视域中舟山海岛研究知识图谱与展望—基于CNKI与WOS数据库的文献计量分析

从地理学与海洋学视域出发, 在阐述舟山海岛独特性和研究价值的基础上, 通过文献计量分析梳理以舟山海岛为研究对象的相关研究脉络, 提出了未来舟山研究值得关注的重点, 即着眼最基本的生产、生活、生态问题研究舟山地区海洋生态环境变化和工农业技术水平的互馈机制, 模拟自然与人文要素的耦合格局、尺度与机理, 为海岛可持续发展决策和社会提供动态信息.