نتایج جستجو برای: Geographical obstacles Distance function Geographic

تعداد نتایج: 1546628  

Jamal Shahrabi Maryam Javadi

The problems of facility location and the allocation of demand points to facilities are crucial research issues in spatial data analysis and urban planning. It is very important for an organization or governments to best locate its resources and facilities and efficiently manage resources to ensure that all demand points are covered and all the needs are met. Most of the recent studies, which f...

2017
Xiaomei Bai Jie Hou Hongzhuang Du Xiangjie Kong Feng Xia

Evaluating the impact of scholarly papers plays an important role for addressing recruitment decision, funding allocation and promotion, etc. Yet little is known how actual geographic distance influences the impact of scholarly papers. In this paper, we leverage the law of geographic distance and citations between different institutions to weight quantum Pagerank algorithm for objectively measu...

2014
Haitao Ma Chuanglin Fang Bo Pang Guangdong Li

BACKGROUND The relations between geographical proximity and spatial distance constitute a popular topic of concern. Thus, how geographical proximity affects scientific cooperation, and whether geographically proximate scientific cooperation activities in fact exhibit geographic scale features should be investigated. METHODOLOGY Selected statistics from the ISI database on cooperatively author...

2004
Artur Ziviani Serge Fdida José Ferreira de Rezende Otto Carlos Muniz Bandeira Duarte

Location-aware applications require a geographic location service of Internet hosts. We focus on a measurement-based service for the geographic location of Internet hosts. Host locations are inferred by comparing delay patterns of geographically distributed landmarks, which are hosts with a known geographic location, with the delay pattern of the target host to be located. Results show a signif...

2011
Jacob van Etten

This vignette describes gdistance, an R package which provides functionality to calculate various distance measures and routes in heterogeneous geographic spaces represented as grids. Distances are fundamental to geospatial analysis (Tobler 1970). The most commonly used geographic distance measure is the great-circle distance, which represents the shortest line between two points, taking into a...

2012
Jacob van Etten

This vignette describes gdistance, an R package which provides functionality to calculate various distance measures and routes in heterogeneous geographic spaces represented as grids. Distances are fundamental to geospatial analysis (Tobler 1970). The most commonly used geographic distance measure is the great-circle distance, which represents the shortest line between two points, taking into a...

Journal: :Ad Hoc Networks 2007
Niklas Carlsson Derek L. Eager

Greedy geographic routing is attractive for large multi-hop wireless networks because of its simple and distributed operation. However, it may easily result in dead ends or hotspots when routing in a network with obstacles (regions without sufficient connectivity to forward messages). In this paper we propose a distributed routing algorithm that combines greedy geographic routing with two non-E...

2003
Jean Monnet

The paper seeks to develop our understanding of the somewhat diffuse nature of technological externalities in technological space by associating a geographical dimension with the sectoral dimension. Using panel data this paper estimates a knowledge production function that allows for spillovers inside the same industry and outside, and for local as well as global geographical spillovers. This a...

2015
Indre Zliobaite Michael Mathioudakis Tuukka Lehtiniemi Pekka Parviainen Tomi Janhunen

This pilot study investigates how considering accessibility could help to model prices of residential real estate more accurately. We introduce two novelties from the price modeling point of view (1) defining accessibility as travel time by public transport, in addition to geographic distance, and (2) considering dynamic points of interest from check-ins into social networks, in addition to fix...

2012
Salvatore Scellato

This dissertation is the result of my own work and includes nothing which is the outcome of work done in collaboration except where specifically indicated in the text. This dissertation does not exceed the regulation length of 60 000 words, including tables and footnotes. Summary Online social networking services entice millions of users to spend hours every day interacting with each other. At ...

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