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International Forum on Information Technology and Applications (IFITA 2009)

作者： Song Guangjun Hao Zhong-xiao Wang Lijie Harbin Univ Sci & Technol Coll Comp & Control Harbin 150080 Peoples R China Qiqihar Univ Coll Comp & Control Engn Qiqihar 161006 Peoples R China Harbin Inst Technol Coll Comp Sci & Technol Harbin 150001 Peoples R China

ISBN: (纸本)9780769536002

In order to get more accurate movement information of moving objects, and to capture the temporal trajectory of the spatial uncertainty, This article describes the uncertain trajectory model of the moving objects in the road networks databases, and extends the structure of the MON-tree index based on the road network. The uncertain geometry between two sampling points is divided into pieces, which are stored into the uncertain area list according to time sorting. To enable them to effectively support the uncertainty of moving objects in the road network, and the probabilistic query of the uncertain region of the moving objects trajectory is carried out on this basis of them. The experiment shows that the index structure as well as the probabilistic query with a better performance and higher accuracy inquiries

关键词： moving objects databases uncertainty probabilistic range query

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Load balancing for processing spatio-temporal queries in multi-core settings

Load balancing for processing spatio-temporal queries in mul...

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11th ACM International Workshop on Data Engineering for Wireless and Mobile Access, MobiDE 2012 - In Conjunction with ACM SIGMOD / PODS 2012

作者： Yaagoub, Anan Trajcevski, Goce Scheuermann, Peter Hardavellas, Nikos Dept. of EECS Northwestern University Evanston IL United States

ISBN: (纸本)9781450314428

We address the problem of efficiently parallelizing the processing of spatio-temporal range queries in multicore settings. Although the data set can be partitioned and assigned to individual cores for processing a collection of range queries, one cannot achieve an "ideal" assignment for all the cores' load. Hence, the cores should collaborate in a dynamic manner: ones that have completed their (sub)tasks should take part of the load from the cores that are still processing some of the data. We provide algorithms and synchronization data structures that achieve such collaborative behavior and we investigate their impact in different initial load-partitioning strategies. Our experiments demonstrate that about 40% speed-up can be gained when compared to static load-partitioning and that the proposed approach scales well. Copyright © 2012 ACM.

关键词： moving objects databases Multicore processing

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Spatiotemporal pattern queries

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GEOINFORMATICA 2011年第3期15卷 497-540页

作者： Sakr, Mahmoud Attia Gueting, Ralf Hartmut Fern Univ Hagen Database Syst New Applicat D-58084 Hagen Germany Ain Shams Univ Fac Comp & Informat Sci Cairo Egypt

This paper presents a novel approach to express and evaluate the complex class of queries in moving object databases called spatiotemporal pattern queries (STP queries). That is, one can specify temporal order constraints on the fulfillment of several predicates. This is in contrast to a standard spatiotemporal query that is composed of a single predicate. We propose a language design for spatiotemporal pattern queries in the context of spatiotemporal DBMSs. The design builds on the well established concept of lifted predicates. Hence, unlike previous approaches, patterns are neither restricted to specific sets of predicates, nor to specific moving object types. The proposed language can express arbitrarily complex patterns that involve various types of spatiotemporal operations such as range, metric, topological, set operations, aggregations, distance, direction, and boolean operations. This work covers the language integration in SQL, the evaluation of the queries, and the integration with the query optimizer. We also propose a simple language for defining the temporal constraints. The approach allows for queries that were never available. We provide a complete implementation in C+ + and Prolog in the context of the Secondo platform. The implementation is made publicly available online as a Secondo Plugin, which also includes automatic scripts for repeating the experiments in this paper.

关键词： moving objects databases Trajectory Lifted predicate Spatiotemporal patterns SECONDO

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An extended k-means technique for clustering moving objects

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EGYPTIAN INFORMATICS JOURNAL 2011年第1期12卷 45-51页

作者： Ossama, Omnia Mokhtar, Hoda M. O. El-Sharkawi, Mohamed E. Cairo Univ Fac Comp & Informat Cairo Egypt

k-means algorithm is one of the basic clustering techniques that is used in many data mining applications. In this paper we present a novel pattern based clustering algorithm that extends the k-means algorithm for clustering moving object trajectory data. The proposed algorithm uses a key feature of moving object trajectories namely, its direction as a heuristic to determine the different number of clusters for the k-means algorithm. In addition, we use the silhouette coefficient as a measure for the quality of our proposed approach. Finally, we present experimental results on both real and synthetic data that show the performance and accuracy of our proposed technique. (C) 2011 Faculty of Computers and Information, Cairo University. Production and hosting by Elsevier B. V. All rights reserved.

关键词： Clustering moving objects moving objects databases Mining moving object trajectories K-means clustering algorithm

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Key techniques for predicting the uncertain trajectories of moving objects with dynamic environment awareness

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Journal of Modern Transportation 2011年第3期19卷 199-206页

作者： Shaojie QIAO Xian WANG Lu＇an TANG Liangxu LIU Xun GONG School of Information Science and Technology Southwest Jiaotong UniversityChengdu 610031China Department of Computer Science University of Illinois at Urbana-ChampaignUrbana 61801USA School of Electronics and Information Engineering Ningbo University of TechnologyNingbo 315016China

Emerging technologies of wireless and mobile communication enable people to accumulate a large volume of time-stamped locations,which appear in the form of a continuous moving object *** to accurately predict the uncertain mobility of objects becomes an important and challenging *** algorithms for trajectory prediction in moving objects databases mainly focus on identifying frequent trajectory patterns,and do not take account of the effect of essential dynamic environmental *** this study,a general schema for predicting uncertain trajectories of moving objects with dynamic environment awareness is presented,and the key techniques in trajectory prediction arc addressed in *** order to accurately predict the trajectories,a trajectory prediction algorithm based on continuous time Bayesian networks（CTBNs） is improved and applied,which takes dynamic environmental factors into full *** conducted on synthetic trajectory data verify the effectiveness of the improved algorithm,which also guarantees the time performance as well.

关键词： trajectory prediction moving objects databases dynamic environmental factors continuous time Bayesian networks

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Trajectory databases: Data models, uncertainty and complete query languages

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JOURNAL OF COMPUTER AND SYSTEM SCIENCES 2010年第7期76卷 538-560页

作者： Kuijpers, Bart Othman, Walied Hasselt Univ Dept Math Phys & Comp Sci B-3590 Diepenbeek Belgium Transnatl Univ Limburg Limburg Belgium

moving objects produce trajectories. We describe a data model for trajectories and trajectory samples and an efficient way of modeling uncertainty via beads for trajectory samples. We study transformations of the ambient space for which important physical properties of trajectories, such as speed, are invariant. We also determine which transformations preserve beads. We give conceptually easy first-order complete query languages and computationally complete query languages for trajectory databases, which allow to talk directly about speed and uncertainty in terms of beads. The queries expressible in these languages are invariant under speed- and bead-preserving transformations. (C) 2009 Elsevier Inc. All rights reserved.

关键词： moving objects databases Spatio-temporal databases Constraint databases Trajectories Trajectory samples Beads Uncertainty

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Uncertainty for Anonymity and 2-Dimensional Range Query Distortion

Uncertainty for Anonymity and 2-Dimensional Range Query Dist...

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Conference on Privacy in Statistical databases 2010

作者： Sioutas, Spyros Magkos, Emmanouil Karydis, Ioannis Verykios, Vassilios S. Ionian Univ Dept Informat Corfu Greece Univ Thessaly Dept Comp & Commun Engn Thessaly Greece

ISBN: (纸本)9783642158377

In this work, we study the problem of anonymity-preserving data publishing in moving objects databases. In particular, the trajectory of a mobile user on the plane is no longer a polyline in a two-dimensional space, instead it is a two-dimensional surface: we know that the trajectory of the mobile user is within this surface, but we do not know exactly where. We transform the surface's boundary poly-lines to dual points and we focus on the information distortion introduced by this space translation. We develop a set of efficient spatio-temporal access methods and we experimentally measure the impact of information distortion by comparing the performance results of the same spatio-temporal range queries executed on the original database and on the anonymized one.

关键词： Uncertainty Privacy Anonymity moving objects databases

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Modeling Trajectories: A Spatio-Temporal Data Type Approach

Modeling Trajectories: A Spatio-Temporal Data Type Approach

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20th International Conference on Database and Expert Systems Applications

作者： Frihida, Ali Zheni, Donia Ben Ghezala, Henda Claramunt, Christophe Univ Tunis El Manar LTSIRS Ecole Natl Ingenieurs Tunis Tunis Tunisia Univ Manouba Ecole Natl Sci Informat RIADI Manouba Tunisia Naval Acad Res Inst Angers France

ISBN: (纸本)9780769537634

Retrieving and analyzing trajectories favor the study of human behaviors in space and time. Although Time Geography has long proposed a conceptual framework for the interpretation of trajectory data, there is still a need for database and semantic models that support representation and manipulation. In fact, the concept of trajectory is rarely addressed as a sui generis data type that can be embedded in a database structure. This paper introduces an algebraic Spatio-Temporal Trajectory data type (STT) for the representation of object trajectory. The STT is an abstract data type endowed with a set of operations designed as a way to cover the syntax and semantics of a given trajectory. It is considered as a data structure that can be used for the design and implementation of spatio-temporal databases.

关键词： abstract data type modeling spatio-temporal trajectory modeling spatio-temporal databases moving objects databases temporal GIS Time Geography

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Managing uncertainty in moving objects databases

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ACM TRANSACTIONS ON DATABASE SYSTEMS 2004年第3期29卷 463-507页

作者： Trajcevski, G Wolfson, O Hinrichs, K Chamberlain, S Northwestern Univ Dept Elect & Comp Engn Evanston IL 60208 USA Univ Illinois Dept Comp Sci Chicago IL 60607 USA Univ Munster Inst Informat FB 10 D-48149 Munster Germany USA Res Lab Aberdeen Proving Ground MD 21005 USA

This article addresses the problem of managing moving objects databases (MODs) which capture the inherent imprecision of the information about the moving object's location at a given time. We deal systematically with the issues of constructing and representing the trajectories of moving objects and querying the MOD. We propose to model an uncertain trajectory as a three-dimensional (3D) cylindrical body and we introduce a set of novel but natural spatio-temporal operators which capture the uncertainty and are used to express spatio-temporal range queries. We devise and analyze algorithms for processing the operators and demonstrate that the model incorporates the uncertainty in a manner which enables efficient querying, thus striking a balance between the modeling power and computational efficiency. We address some implementation aspects which we experienced in our DOMINO project, as a part of which the operators that we introduce have been implemented. We also report on some experimental observations of a practical relevance.

关键词： algorithms moving objects databases

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Geometric Modeling and visualization of moving objects on a digital map

Geometric Modeling and visualization of moving objects on a ...

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2nd International Conference on Geometric Modeling and Imaging

作者： Kilimci, Perihan Kalipsiz, Oya Yildiz Tech Univ Turkish Air Force Acad Dept Comp Engn Istanbul Turkey

ISBN: (纸本)9780769529011

In order to model geographic space, we should consider obviously anything qualifies that might appear on a paper map for example, states, cities, mountains, rivers, highway networks, hospitals, police stations etc. These varied entities can be modeled by using geometric modeling concepts. In many internet applications and Geographical Information Systems (GIS) digital maps are used to indicate locations of interested static or moving objects which change their futures in spatial and temporal domain. In this paper, we visualized a spatial map which stores its data according to geometric modeling concepts and retrieves its data from database. Then, we simulated moving objects on a digital map according to predefined scenario.

关键词： geometric modeling moving objects databases

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