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Location-Based Data Dissemination for spatial Queries in Wireless Broadcast Environments

Journal of Computer Science & Technology 2010年第2期25卷 330-346页

作者： Kwangjin Park Hyunseung Choo School of Electrical Electronics and Information Engineering Wonkwang University School of Information and Communication Engineering Sungkyunkwan University

Most current research on Location-Based Services （LBSs, for short） assumes point-to-point wireless commu- nication, where the server processes a query and returns the query result to the user via a point-to-point wireless channel. However, LBSs via point-to-point wireless channel suffer from a tremendous amount of tramc and service requests from the user and thereby result in poor performance. In this paper, we present broadcast-based spatial query processing algorithms designed to support k-NN （k-Nearest Neighbor） and range queries via a wireless network. The task of the query processor is to selectively monitor the wireless broadcast channel, when the data items are disseminated by the server, according to their locations. Experiments are conducted to evaluate the performance of the proposed algorithms. Comprehensive experiments illustrate that the presented algorithms are highly scalable and are more efficient than the previous techniques in terms of both access time and energy consumption.

关键词： distributed databases indexing methods information storage and retrieval spatial databases and gis

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Interoperable spatial Information Model and Design Environment Based on ucR Technology

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IEICE TRANSACTIONS ON INFORMATION AND SYSTEMS 2013年第1期E96D卷 51-63页

作者： Shigesada, Yukihiko Kobayashi, Shinsuke Koshizuka, Noboru Sakamura, Ken Hosei Univ Tokyo 1028160 Japan YRP Ubiquitous Networking Lab Tokyo 1410031 Japan Univ Tokyo Tokyo 1130033 Japan

Context awareness is one of the ultimate goals of ubiquitous computing, and spatial information plays an important role in building context awareness. In this paper, we propose a new interoperable spatial information model, which is based on ucode relation (ucR) and Place Identifier (PI), for realizing ubiquitous spatial infrastructure. In addition, we propose a design environment for spatial information database using our model. Our model is based on ucode and its relation. ucode is 128 bits number and the number itself has no meaning. Hence, it is difficult to manage the relation between ucodes without using a tool. Our design environment provides to describe connection between each ucode visually and is able to manipulate data using the target space map interactively. To evaluate the proposed model and environment, we designed three spaces using our tool. In addition, we developed a web application using our spatial model. From evaluation, we have been showed that our model is effective and our design environment is useful to develop our spatial information model.

关键词： spatial information system ubiquitous computing ubiquitous spatial infrastructure spatial databases and gis web based services

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A family of directional relation models for extended objects (vol 19, pg 1116, 2007)

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IEEE TRANSACTIONS ON KNOWLEDGE AND DATA ENGINEERING 2007年第10期19卷 1448-1448页

作者： Skiadopoulos, Spiros Sarkas, Nikos Sellis, Timos Koubarakis, Manolis Univ Peloponnese Dept Comp Sci & Technol Tripoli 22100 Libya Univ Toronto Dept Comp Sci Toronto ON M5S 3G4 Canada Natl Tech Univ Athens Div Comp Sci Sch Elect & Comp Engn GR-15773 Zografos Greece Univ Athens Natl & Kapodistrian Dept Informat & Telecommun GR-15784 Athens Greece

In this paper, we introduce a family of expressive models for qualitative spatial reasoning with directions. The proposed family is based on the cognitive plausible cone-based model. We formally define the directional relations that can be expressed in each model of the family. Then, we use our formal framework to study two interesting problems: computing the inverse of a directional relation and composing two directional relations. For the composition operator, in particular, we concentrate on two commonly used definitions, namely, consistency-based and existential composition. Our formal framework allows us to prove that our solutions are correct. The presented solutions are handled in a uniform manner and apply to all of the models of the family. [ABSTRACT FROM AUTHOR]

关键词： cone-based directional relations inverse and composition operators spatial databases and gis

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Processing of Continuous Location-Based Range Queries on Moving Objects in Road Networks

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IEEE TRANSACTIONS ON KNOWLEDGE AND DATA ENGINEERING 2011年第7期23卷 1065-1078页

作者： Wang, Haojun Zimmermann, Roger Univ So Calif Dept Comp Sci Los Angeles CA 90089 USA Natl Univ Singapore Dept Comp Sci Sch Comp Singapore 117417 Singapore Natl Univ Singapore IDMI Singapore 117417 Singapore

With the proliferation of mobile devices, an increasing number of urban users subscribe to location-based services. This trend has led to significant research interest in techniques that address two fundamental requirements: road network-based distance computation and the capability to process moving objects as points of interests. However, there exist few techniques that support both requirements simultaneously. To address these challenges, we propose a novel approach to process continuous range queries. We build on our previous work of an infrastructure that supports location-based snapshot queries on MOVing objects in road Networks (MOVNet). We introduce several significant features to enable continuous queries. The dual index structure that we proposed for MOVNet has been appropriately modified. We further appoint a number of connecting vertices in each cell and precompute the distances among them to expedite query processing. Most importantly, to alleviate the effects of frequent object updates, we introduce a Shortest-Distance-based Tree (SD-Tree). We illustrate that the network connectivity and distance information can be preserved and reused by the SD-Tree when the query point location is updated;hence, reducing the continuous query update cost. Our experimental results demonstrate that our method yields excellent performance with a very large number of moving objects.

关键词： spatial databases and gis location-dependent and sensitive

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ANTS -: Augmented environments

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COMPUTERS & GRAPHICS-UK 2004年第5期28卷 625-633页

作者： Romao, T Correia, N Dias, E Danado, J Trabuco, A Santos, C Santos, R Câmara, A Nobre, E Univ Evora Dept Comp Sci P-7000 Evora Portugal Univ Nova Lisboa Dept Comp Sci P-2825 Monte De Caparica Portugal Univ Nova Lisboa CITI P-2825 Monte De Caparica Portugal Univ Nova Lisboa Environm Syst Anal Grp P-2825 Monte De Caparica Portugal

Interaction with natural or urban environments creates numerous situations where it is relevant to have access to further information that we cannot perceive by direct observation through our senses. Augmented Reality (AR) technologies allow real time superimposition of synthetic objects on real images, providing an augmented knowledge about the surrounding world. Users of an AR system can visualize the real surrounding world together with additional data generated in real time in a contextual way. This paper presents the ANTS project, which carries out the development of an AR technological infrastructure that can be used to explore physical and natural structures, namely for environmental management purposes. The system's architecture has a flexible design based on a client-server model, where several independent, but functionally interdependent modules are articulated. Therefore, modules can be moved from the server side to the client side or vice versa, according to the client processing capacity. Several applications have been developed and are also discussed in this paper. (C) 2004 Elsevier Ltd. All rights reserved.

关键词： multimedia information systems augmented and virtual realities simulation and modelling applications spatial databases and gis spatial information systems

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Bichromatic Reverse Nearest-Neighbor Search in Mobile Systems

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IEEE SYSTEMS JOURNAL 2010年第2期4卷 230-242页

作者： Tran, Quoc Thai Taniar, David Safar, Maytham Monash Univ Clayton Sch Informat Technol Melbourne Vic 3004 Australia Kuwait Univ Dept Comp Engn Safat Kuwait

In traditional reverse nearest-neighbor (RNN) search, the goal is to find the set of interest objects taking the query object as the nearest neighbor given that the interest objects and the query object have the same type. However, when the interst objects and the query object are of different types, this problem is called bichromatic reverse nearest neighbor (BRNN) search. The BRNN query has an increasing number of mobile applications and requires efficient algorithms for processing. In this paper, we present a novel approach for the BRNN search in the context of spatial network databases (SNDB). The main idea behind our approaches is to use Euclidean-based range search to prune the search space and use Euclidean distance in addition to network distance to minimize processing time. Finally, the experimental results confirm that our proposed algorithm have good performance on different network densities.

关键词： Mobile systems nearest neighbor searches network Voronoi diagrams query processing spatial databases and gis

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Placegram: A Diagrammatic Map for Personal Geotagged Data Browsing

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IEEE TRANSACTIONS ON VISUALIZATION AND COMPUTER GRAPHICS 2010年第2期16卷 221-234页

作者： Jo, Hyungeun Ryu, Jung-hee Korea Adv Inst Sci & Technol Grad Sch Culture Technol Taejon 305701 South Korea

Geotagging personal data such as photos and videos are continuously becoming easier and more popular. Nevertheless, browsing such data on general purpose maps can be difficult, due to the frequent zoom and pan operations as well as visual components unnecessary for the task. This paper presents Placegram, a compact diagrammatic map visualization for personal geotagged data browsing based on cognitive map theories. An evaluation using real-life data sets shows that the speed of finding and pointing to places from the participants' own data increased by a factor of 2.1-2.9, and the number of interesting places discovered from others' data within a time limit increased by 48.8 percent in Placegram compared to a general purpose map. Placegram was even slightly faster than a simple text list, while at the same time, preserving the geographic senses of direction and location. Subjective ratings and comments from participants support these results, indicating that Placegram is significantly preferred over both a general map and a text list.

关键词： Information visualization graphical user interfaces spatial databases and gis multimedia information systems

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Aggregate nearest neighbor queries in road networks

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IEEE TRANSACTIONS ON KNOWLEDGE AND DATA ENGINEERING 2005年第6期17卷 820-833页

作者： Yiu, ML Mamoulis, N Papadias, D Univ Hong Kong Dept Comp Sci Pokfulam Rd Hong Kong Hong Kong Peoples R China Hong Kong Univ Sci & Technol Dept Comp Sci Hong Kong Hong Kong Peoples R China

Aggregate nearest neighbor queries return the object that minimizes an aggregate distance function with respect to a set of query points. Consider, for example, several users at specific locations (query points) that want to find the restaurant ( data point), which leads to the minimum sum of distances that they have to travel in order to meet. We study the processing of such queries for the case where the position and accessibility of spatial objects are constrained by spatial ( e. g., road) networks. We consider alternative aggregate functions and techniques that utilize Euclidean distance bounds, spatial access methods, and/or network distance materialization structures. Our algorithms are experimentally evaluated with synthetic and real data. The results show that their relative performance depends on the problem characteristics.

关键词： query processing spatial databases spatial databases and gis location-dependent and sensitive

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Geo-Store: A Framework for Supporting Semantics-Enabled Location-Based Services

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IEEE INTERNET COMPUTING 2013年第2期17卷 35-43页

作者： Ku, Wei-Shinn Chen, Haiquan Wang, Chih-Jye Liu, Chuan-Ming Auburn Univ Dept Comp Sci & Software Engn Auburn AL 36849 USA Valdosta State Univ Dept Math & Comp Sci Valdosta GA USA Natl Taipei Univ Technol Dept Comp Sci & Informat Engn Taipei Taiwan

Location-based services (LBSs) are popular information services for mobile users, who access them using location-aware mobile devices over wireless networks. To enable devices to understand and exchange information on the Web, LBS providers use Semantic Web data sources to develop semantics-enabled LBSs. However, there are currently limited solutions for processing spatial queries, the building blocks of most LBSs, on Semantic Web data to support these services. The Geo-Store system evaluates spatial queries on RDF triple stores (Semantic Web data management systems) to provide semantics-enabled LBSs.

关键词： Data models Mobile handsets Query processing Resource description framework spatial databases database applications database management information technology and systems query processing spatial databases and gis

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Real-Time City-Scale Taxi Ridesharing

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IEEE TRANSACTIONS ON KNOWLEDGE AND DATA ENGINEERING 2015年第7期27卷 1782-1795页

作者： Ma, Shuo Zheng, Yu Wolfson, Ouri Univ Illinois Dept Comp Sci Chicago IL 60607 USA Microsoft Res Beijing 100080 Peoples R China

We proposed and developed a taxi-sharing system that accepts taxi passengers' real-time ride requests sent from smartphones and schedules proper taxis to pick up them via ridesharing, subject to time, capacity, and monetary constraints. The monetary constraints provide incentives for both passengers and taxi drivers: passengers will not pay more compared with no ridesharing and get compensated if their travel time is lengthened due to ridesharing;taxi drivers will make money for all the detour distance due to ridesharing. While such a system is of significant social and environmental benefit, e. g., saving energy consumption and satisfying people's commute, real-time taxi-sharing has not been well studied yet. To this end, we devise a mobile-cloud architecture based taxi-sharing system. Taxi riders and taxi drivers use the taxi-sharing service provided by the system via a smart phone App. The Cloud first finds candidate taxis quickly for a taxi ride request using a taxi searching algorithm supported by a spatio-temporal index. A scheduling process is then performed in the cloud to select a taxi that satisfies the request with minimum increase in travel distance. We built an experimental platform using the GPS trajectories generated by over 33,000 taxis over a period of three months. A ride request generator is developed (available at http://***/similar to sma/ridesharing) in terms of the stochastic process modelling real ride requests learned from the data set. Tested on this platform with extensive experiments, our proposed system demonstrated its efficiency, effectiveness and scalability. For example, when the ratio of the number of ride requests to the number of taxis is 6, our proposed system serves three times as many taxi riders as that when no ridesharing is performed while saving 11 percent in total travel distance and 7 percent taxi fare per rider.

关键词： spatial databases and gis taxi-sharing GPS trajectory ridesharing urban computing intelliegent transportation systems

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