Dragan Stojanovic

Searching for similar trajectories in spatial networks

In several applications, data objects move on pre-defined spatial networks such as road segments, railways, and invisible air routes. Many of these objects exhibit similarity with respect to their traversed paths, and therefore two objects can be correlated based on their motion similarity. Useful information can be retrieved from these correlations and this knowledge can be used to define similarity classes. In this paper, we study similarity search for moving object trajectories in spatial networks. The problem poses some important challenges, since it is quite different from the case where objects are allowed to move freely in any direction without motion restrictions. New similarity measures should be employed to express similarity between two trajectories that do not necessarily share any common sub-path. We define new similarity measures based on spatial and temporal characteristics of trajectories, such that the notion of similarity in space and time is well expressed, and moreover they satisfy the metric properties. In addition, we demonstrate that similarity range queries in trajectories are efficiently supported by utilizing metric-based access methods, such as M-trees.

ExposureSense: Integrating daily activities with air quality using mobile participatory sensing

With an increasing number of rich embedded sensors, like accelerometer and GPS, smartphone becomes a pervasive people-centric sensing platform for inferring users daily activities and social contexts. Alternatively, wireless sensor network offers a comprehensive platform for capturing the surrounding environmental information using mobile sensing nodes, e.g., the OpenSense project [2] in Switzerland deploying air quality sensors like CO on public transports like buses and trams. The two sensing platforms are typically isolated from each other. In this paper, we build ExposureSense, a rich mobile participatory sensing infrastructure that integrates the two independent sensing paradigms. ExposureSense is able to monitor peoples daily activities as well to compute a reasonable estimation of pollution exposure in their daily life. Besides using external sensor networks, ExposureSense also supports pluggable sensors (e.g., O3) to further enrich air quality data using mobile participatory sensing with smartphones.

Trajectory Similarity Search in Spatial Networks

In several applications, data objects are assumed to move on predefined spatial networks such as road segments, railways, and invisible air routes. Moving objects may exhibit similarity with respect to their traversed paths, and therefore two objects can be correlated based on their path similarity. In this paper, we study similarity search for moving object trajectories for spatial networks. The problem poses some important challenges, since it is quite different from the case where objects are allowed to move without motion restrictions. Experimental results performed on real-life spatial networks show that trajectory similarity can be supported in an effective and efficient manner by using metric-based access methods

Continuous range monitoring of mobile objects in road networks

In contrast to regular queries that are evaluated only once, a continuous query remains active over a period of time and has to be continuously evaluated to provide up to date answers. We propose a method for continuous range query processing for different types of queries, characterized by mobility of objects and/or queries which all follow paths in an underlying spatial network. The method assumes an available 2D indexing scheme for indexing spatial network data. An appropriately extended R*-tree, that primarily is used as an indexing scheme for network segments, provides matching of queries and objects according to their locations on the network or their network routes. The method introduces an additional pre-refinement step which generates main-memory data structures to support efficient, incremental reevaluation of continuous range queries in periodically performed refinement steps.

Semantic management of moving objects

We review the state-of-the-art in the semantic representation of moving objects.We present the key research challenges for the semantic management of moving objects.We propose a scalable framework for the semantic management of moving objects.The framework supports a distributed storage and analysis of semantic mobility data. This position paper presents our vision for the semantic management of moving objects. We argue that exploiting semantic techniques in mobility data management can bring valuable benefits to many domains characterized by the mobility of users and moving objects in general, such as traffic management, urban dynamics analysis, ambient assisted living, emergency management, m-health, etc. We present the state-of-the-art in the domain of management of semantic locations and trajectories, and outline research challenges that need to be investigated to enable a full-fledged and intelligent semantic management of moving objects and location-based services that support smarter mobility. We propose a distributed framework for the semantic enrichment and management of mobility data and analyze the potential deployment and exploitation of such a framework.

Web information system for transport telematics and fleet management

In this paper, a Web information system for fleet management and transport telematics is described. The system is developed based on MOWIS - a service-oriented open software platform for location-based and context-aware mobile and Web applications. Based on MOWIS services such as routing service, directory service, traffic information service and moving object service, as well as real AVL bus tracking data, the Web information system developed possess all functionalities needed for vehicle tracking, fleet control and management available for Web fleet control users.

Cysticercosis cerebri involving the lateral ventricle

Cysticercosis cerebri involving the lateral ventricle is very rare. Two cases with such localization are presented. One of the patients, with occlusion of the foramen of Monro, was successfully treated by operation. A larval form in the lateral ventricle was revealed incidentally at autopsy in the second patient after rupture of a large basilar artery aneurysm.

Prediction of bus motion and continuous query processing for traveler information services

The paper presents the methods for prediction of bus arrival times and continuous query processing as foundations of traveler information services. The time series of data from automatic vehicle location (AVL) system, consisting of time, location and speed data, is used with historical statistics and bus schedule information to predict future arrivals and motion. Based on predicted and AVL data, continuous query processing technique is proposed to extend traveler information service with notification/alarm features. Extensive experiments have shown that the proposed algorithm for bus motion prediction is efficient enough to function in real conditions and that augmented with continuous query processing techniques can produce services that useful to the travelers.

High-performance computing in GIS: techniques and applications

In this paper, the application of High-Performance Computing (HPC) techniques in processing of geospatial data in Geographic Information System (GIS) is presented. We evaluate two parallel/distributed architectures and programming models: Message Passing Interface (MPI) over Network of Workstations (NoW) and Compute Unified Device Architecture (CUDA) on Graphics Processing Unit (GPU) in well-known problems in GIS: map matching and slope computations. A distributed application for map-matching computation over large-spatial data sets consisting of moving points and a road network was implemented using MPI and experimentally evaluated. A slope computations based on large-digital elevation model data was performed on GPU using CUDA which enable hundreds of threads to run concurrently employing multiprocessors on a graphics card. Experimental evaluations indicate improvement in performance and shows feasibility of using NoW and multiprocessors on a graphic card for HPC in GIS.

Visual query and analysis tool of the object-relational GIS framework

Information Systems (GISs) have become an essential tool for efficient handling of our natural and artificial environment. The most important activities in a GIS are querying and spatial analysis of georeferenced data providing decision making and problem solving support. Traditional database query languages and tools are inappropriate for GIS purpose, because of their inability to address spatial properties of the real world entities. This paper presents a spatial query and analysis tool with the strong visual context, called GeoQA. It has been developed as an integral component of the GinisNT, object-oriented GIS framework for GIS applications development. GeoQA provides effective, interactive but user-friendly and ease-of-use mechanisms for performing spatial and non-spatial queries, as well as, spatial, thematic and statistic analysis in specific GIS applications developed on the top of GinisNT.