Improvement of a location-aware recommender system using volunteered geographic information

Abstract

Recommender systems (RS), as supportive tools, filter information from a massive amount of data based on the determined preferences. Most of the RS require information about the context of users such as their locations. In such cases, location-aware recommender systems (LARS) can be employed to suggest more personalized items to the users. The most current research projects on LARS focus on the development of algorithms, evaluation methods and applications. However, the role of up-to-date spatial databases in LARS is not a well-researched area. The up-to-date spatial information would potentially improve the accuracy of items which are recommended by LARS. Volunteered geographic information (VGI) could be a low-cost source of up-to-date spatial information for LARS. This article proposes an approach to enrich spatial databases of LARS by VGI. Since not all records of VGI are fitted for use in LARS, a mechanism is developed to identify useful information. Some VGI data sets refer to existing spatial data in the database while other VGI data sets are shared for the first time. Therefore, the proposed method assessed the quality of VGI with reference source (for VGI which is existed in the database) and VGI without reference source (for VGI which is shared for the first time). To demonstrate the feasibility of the proposed approach, a mobile application has been developed to recommend suitable restaurants to the users based on their geospatial locations. The evaluation of the method indicates that VGI can potentially enhance the functionality of the LARS in predicting the users’ interests.     

Monitoring the built-up environment of Shanghai on the street-block level using SAR and volunteered geographic information

ABSTRACT

In this geo-statistical analysis of change detection, we illustrate the evolution of the built-up environment in Shanghai at the street-block level. Based on two TerraSAR-X image stacks with 36 and 15 images, covering the city centre of Shanghai for the time period from 2008 to 2015, a set of coherence images was created using a small baseline approach. The road network from Open Street Map, a volunteered geographic information product, serves as the input dataset to create street-blocks. A street-block is surrounded by roads and resembles a ground parcel, a real estate property – a cadastral unit. The coherence information is aggregated to these street-blocks for each observation and the variation is analysed over time. An analysis of spatial autocorrelation reveals clusters of similar behaviours. The result is a detailed map of Shanghai highlighting areas of change. We argue that the aggregation and grouping of synthetic aperture radar coherence image information to real-world entities (street-blocks) is comprehensible and relevant to the urban planning process. Therefore, this research is a contribution to the community of urban planners, designers, and government agencies who want to monitor the development of the urban landscape.     

兼顾志愿者地理信息的国家应急测绘公众服务平台设计

随着互联网技术的进步和新一代网络信息传播模式的深入发展,志愿者地理信息的研究和应用日益广泛,但由于其规范性和均一性方面的缺陷,在应急公共服务领域,志愿者信息的有效利用依旧是亟需突破的难题。本文将重点介绍国家应急测绘公众服务平台设计思路和总体架构,并结合志愿者地理信息特点,探讨该类信息在国家应急测绘公众服务平台建设中的处理流程和应用模式,力求在应急信息资源共享和服务平台共建方面进行新的尝试,为我国突发事件应急体系建设提供有益实践。     

基于ArcGIS Server构建地理信息服务

地理信息服务是构建在Web Services技术之上全新的WebGIS解决方案。ArcGIS Server作为ESRI推出的一个创建企业级GIS应用平台,它的出现使得构建地理信息服务变得十分方便。本文在分析ArcGIS Server体系结构和内部实现机制的基础上,通过构建地址定位服务实例展示了基于ArcGIS Server构建地理信息服务的可行性。     

志愿者地理信息数据质量研究现状与趋势

针对志愿者地理信息的质量评价问题,对当前的研究现状和存在问题进行了较为全面的综述。有关志愿者地理信息数据质量分析与评估的研究也是该领域的研究热点,国内外学者从不同的角度进行了研究,依据是否使用参考数据分为基于参考数据的方法和基于数据分析的方法。总结了基于参考数据方法的基本流程,论述了两种评价方法中具有代表性的研究成果,分析了这些方法的特点和不足,最后指出了现有研究中存在的问题和进一步需要研究的方向。     

基于业务模板的地理信息服务语义集成方法研究

本文总结了地理信息服务集成研究进展,分析了当前的地理信息服务集成存在的问题,讨论了业务模板的概念、形式化描述和特征,提出了业务模板的设计原则和应用方法,,最后通过实例验证了本文所述方法.     

基于本体集成的地理信息分类分级表达研究

介绍地理本体的基本概念、结构及其建模方法,通过分析地理信息分类分级存在的问题,提出通过构建地理本体并利用地理本体的丰富的语义性和便利的可操作性,对地理信息进行分类分级的方法,实现不同分类分级标准之间的集成与互操作,为解决因信息分类分级产生的数据语义异构性所带来的应用难题提供理论与技术的参考。     

地理信息资源产权政策研究

地理信息资源产权是地理信息共享和地理信息产业研究中的一个十分重要的问题,而这方面的研究在我国尚处于起步阶段。本文阐明了地理信息资源产权的概念,论述了我国地理信息资源产权的主要权利内容,分析了国内外地理信息资源产权政策的现状,指出了我国地理信息资源产权政策存在的主要问题,并提出了国家宜实行的有关地理信息资源产权政策建议。     

Change of geographic information service model in mobile context

IntroductionGreat progress of scientific and technologicalcivilization dramatically i mproves the interactivemethods between people and world. At the sameti me various intelligent mobile terminals spreadInternet over anywhere in human’s life . Mobilecomputing and mobility of computational toolswill reform traditional geographic informationservice model ,combine seamlessly people ,real-ity and digital world through networks each oth-er ,achieve interoperability without li mitation ofti me and …     

A framework for user-generated geographic content acquisition in an age of crowdsourcing

ABSTRACT

Obtaining useful geographic information from the flood of user-generated geographic content (UGGC) data is of significant interest, but comes with challenges in an age of crowdsourcing. To address this issue, we adopt Maslow’s model of human needs to frame UGGC. Synthesizing across literature about volunteered geographic information and participatory GIS, we present a conceptual framework for characterizing collection of UGGC. The framework is composed of multiple dimensions and levels that include perspectives about motivations, participatory methods, and participants. We also articulate four levels of participants (stakeholders, core-engaged participants, semi-core-engaged participants, and engaged citizens) together with four work principles (communication, cooperation, coordination, and collaboration). Finally, a case study describes an example we use to evaluate the conceptual framework for its suitability in design of a UGGC system. We conclude by reflecting on how and why this framework offers a valuable perspective for deriving useful geographic information and offer future research directions.