=Paper=
{{Paper
|id=None
|storemode=property
|title=Enable Location-based Services with a Tracking Framework
|pdfUrl=https://ceur-ws.org/Vol-780/paper5.pdf
|volume=Vol-780
}}
==Enable Location-based Services with a Tracking Framework==
https://ceur-ws.org/Vol-780/paper5.pdf
Enable Location-based Services with a Tracking
Framework
Mareike Kritzler
University of Muenster, Institute for Geoinformatics,
Weseler Str. 253, 48151 Münster, Germany
kritzler@uni-muenster.de
Abstract. In order to obtain information and knowledge about moving
entities, spatio-temporal data needs to be collected and analyzed. The
idea is to establish a generic tracking framework that is able to integrate,
combine, process and analyze spatio-temporal data that is obtained from
heterogeneous data sources. This framework allows for the establishment
of new location-based services for different scenarios in various domains.
Keywords: Location-based service, spatio-temporal data, data fusion,
data analysis
1 Introduction
The knowledge of movement and behavior patterns of moving entities such as
humans, animals and objects is important in marketing, industrial engineering
and behavioral biology, for example. In order to gain this knowledge, spatio-
temporal data, which contains implicit information about the movement and
behavioral patterns of tracked entities, has to be gathered and analyzed. Track-
ing systems (such as the Cricket system [3] or the project RADAR [1] for exam-
ple), which incorporate different localization technologies and methods, gather
spatio-temporal data from moving entities. The number and diversity of track-
ing systems has rapidly increased in recent years. A single system does often
not suit scenario’s requirements, such as accuracy and precision, or has physi-
cal limitations. Thus, the combination of more than one system is necessary for
data collection. The lack of uniformity for tracking systems and insufficiently
applied analysis methods call for a more general approach for spatio-temporal
data integration and analysis in order to gain information about or for tracked
entities.
2 Problems
Different challenges exist regarding the tracking of moving entities and infor-
mation gaining from spatio-temporal data. Depending upon tracked entities,
tracking environments and scenarios, many heterogeneous tracking systems are
simultaneously in use in order to gather spatio-temporal data. This leads to a
2 Enable Location-based Services with a Tracking Framework
variety of data sources as well as a huge amount of spatio-temporal data which
has to be processed and analyzed in order to gain information or knowledge.
P1. An overall approach does not exist to integrate and process spatio-temporal
data obtained by different data sources.
– An architecture needs to be developed to integrate different spatio-
temporal data.
– Methods have to be established for the processing of spatio-temporal
data from different data sources.
P2. A general approach to propose a reusable solution is missing for more than
a single problem in a certain scenario.
– A scale-invariant modeling of the environment and of the scenarios have
to be created.
– A reusable concept for data processing and a generic approach for mod-
eling different scenarios have to be developed.
P3. A standardized format to combine spatio-temporal data with different prop-
erties is missing.
– A standardized data schema for a common data management has to be
designed.
– A fusion of all gathered spatio-temporal data has to be considered for a
continuous localization result.
P4. A set of reusable methods to analyze this data is missing, thus very little
information is previously able to be obtained.
– Different top-down analysis methods need to be developed to obtain
information out of the processed spatio-temporal data.
– Different bottom-up analysis methods need to be developed to obtain
information out of the processed spatio-temporal data.
3 Motivation and Idea
The motivation is to find solutions to the four problems mentioned above and
to support humans in their daily routines based upon collected spatio-temporal
data.
The overall idea is to be able to replace multiple applications that are only
in use for one certain scenario in a particular domain. This application should
result in a homogeneous data set that allows the user to gain information about
tracked entities.
Thus, the idea is to establish an interdisciplinary scientific tool that allows
for the integration and combination of spatio-temporal data obtained from het-
erogeneous tracking systems in scenarios of different domains. The tracking data
can be continuous or non-continuous and accurate or inaccurate. The idea is to
provide a data schema that allows for the integration of non-continuous and
accurate with continuous and inaccurate data: Different tracking systems have
different properties. For example, proxy sensors (such as touch screens or key-
boards, for example) deliver 100% accurate positions because they have fixed
Enable Location-based Services with a Tracking Framework 3
coordinates and a tracked entity has to be at that location in order to trigger
a sensor; on the other hand, this data is not continuous in space because of the
spare distribution of proxy sensors. A tracking system based upon radio-waves
produces continuous data but the data obtained with ratio-waves underlies vari-
ations in the accuracy. This non-continuous proxy sensor data could be combined
with continuous radio-wave data to fill the gaps between the proxy sensors. If
data of two or more partially inaccurate tracking systems is available for the
same time point, the combination of this data can also lead to a more precise
and more accurate tracking result than the data from only one sensor.
4 Goals and Contribution
The goal is the development and establishment of a generic, scale-invariant in
space and time, data fusion and analysis model for collected spatio-temporal
data. The resulting tracking framework addresses the four problems listed above.
Furthermore, the information obtained from different kinds of moving entities is
independent of size and environment.
The goals for the proposed tracking framework include the integration, stor-
ing, processing and analyzing of spatio-temporal data. The focus is not to develop
new systems to collect data nor the provision of drivers for existing technologies
but to integrate and combine data from existing systems.
Fig. 1. The four components of the tracking framework
The contribution of the proposed tracking framework is to provide a gen-
eral approach to integrate and to analyze the spatio-temporal data obtained by
4 Enable Location-based Services with a Tracking Framework
various tracking systems with visualization, statistics, machine learning meth-
ods and graph-based analysis to generate a benefit to the domain experts. The
tracking framework is divided into four different components and incorporates
three differently equipped scenarios to show the generic and extensible approach
(see figure 1).
Furthermore, the data can be processed together and used in different anal-
ysis modules - depending upon the level of instrumentation in the tracking envi-
ronment - to obtain information (see figure 2). The framework can be applied to
tracking tasks in different domains. Different domains contain various levels of
instrumentation, starting with a low instrumentation consisting of proxy sensors
up to smart environments with a dense instrumentation through different track-
ing systems. Integrated and processed data leads to knowledge about tracking
entities in the available analysis modules.
Fig. 2. The idea of a scientific tool that is able to process data in different analysis
modules.
In the case that the user is not the entity to be located, experimental scientists
(such as biologists) could be supported in their daily work by allowing them to
collect and process large quantities of moving entity data. Important information
and knowledge about movement and behavior patterns of animals, for example,
could be obtained from the processed data.
If the user of the framework is the same as the tracked entity, tracked peo-
ple (such as service technicians) could get assistance while following their daily
workflows by taking their location into consideration. Further information about
the tracking environment or their tasks, for example, could be provided based
upon the current coordinates.
Enable Location-based Services with a Tracking Framework 5
5 Tracking Framework
The generic tracking framework is able to integrate, process and analyze spatio-
temporal data which is obtained from heterogeneous data sources. This frame-
work considers combinations of several tracking systems as well as the integration
of data from proxy sensors, such as touch screens, with a fixed location in an
environment. Furthermore, the analysis of moving entities is scale-independent
with regard to spatial and temporal resolution. The framework allows for new
location-based services which provide an additional benefit to their users based
upon spatio-temporal movement and behavior.
The framework addresses the problems of missing uniformity and insuffi-
ciently provided methods. Integration and processing of spatio-temporal data
obtained by different tracking systems is enabled with the provision of a homo-
geneous data schema for spatio-temporal data and metadata. The data schema
specifies units for measurement and time. The framework is implemented mod-
ular in order to allow for further extensions and uses a relational database man-
agement system for data storage.
For the fusion the following cases have to be considered: If more than one
measurement for the same time is available by different tracking systems, the
fusion of one or more coordinates has to be done. In the case that one data entry
has already 100% confidence, the coordinate of this entry is used for the partic-
ular point in time. Alternatively, if both entries have less than 100% confidence,
the data is fused by using a weighted mean of the values. The weight can be
determined with different approaches such as with a simple motion model which
is proposed by [2].
In order to allow for the analysis of spatio-temporal data, bottom-up and top-
down analysis methods are provided. Machine learning methods are provided in
order to find movement and behavior patterns in large data sets in a group of
tracked entities. If the focus is on investigation of differences between different
tracked groups, statistical analysis is used. In the case that non-continuous local-
ization data is available, but a continuous track should be reconstructed, tracks
are simulated with a graph-based approach. Furthermore, a graph matching ap-
proach is provided, which matches existing patterns in obtained data for the
detection of existing movement and behavior patterns. Finally, to assist with
visual analysis of one or more tracked entities in their environment, the display
of a three-dimensional environmental model with the display of the movement
of tracked entities based upon the collected data is available in the framework
(see figure 3).
The framework has limitations that are not part of the research which are
briefly listed in the following. The framework does not integrate sensor sources,
only their data. Furthermore, it does not provide drivers for the integration
of technologies. Only Cartesian coordinates are considered in the data model.
The analysis of real-time tracking data is not part of the current version of
the tracking framework. The framework neither provides methods for visual
modelling nor considers any privacy issues.
6 Enable Location-based Services with a Tracking Framework
Fig. 3. Screenshot of the tracking framework prototype
5.1 Scenarios
Different sizes and characteristics of moving entities are considered as well as
different tracking environments. Data is gathered with proxy sensors that are
available in the tracking environment. In this case the framework demonstrates
the ability to obtain track information from anonymous discrete movement data
which lacks temporal information. Graphed-based simulations illustrate paths
that could have been taken by moving entities under the assumption of different
movement and behavior patterns. Data is also obtained from a certain tracking
system. Then, visual, statistical, machine learning-based and graph-matching
analysis are in use to gather information and obtain knowledge about move-
ment and behavior patterns. The use of computational methods allows for the
finding of more patterns in the data. Furthermore, data is collected in smart
environments (such as the SmartFactory1 or the Innovative Retail Laboratory2 ,
for example) which uses many different tracking systems. A data schema for a
common management of the data allows for the combination of the different tech-
nologies. A visualization of the multi-target tracking provides spatial support in
a smart environment.
In order to emphasize the generic approach of the tracking framework, three
distinct scenarios in different domains are used to develop and apply the tracking
1
SmartFactory. SmartFactory. Available from: http://www.smartfactory-kl.de/ (Ac-
cessed April 4, 2011).
2
DFKI. Innovative Retail Laboratory. Available from:
http://www.dfki.de/web/research/irl/index html?set language=en&cl=en (Ac-
cessed April 4, 2011).
Enable Location-based Services with a Tracking Framework 7
framework. Real world scenarios for the tracking framework include the tracking
of: department store customers, laboratory mice and service technicians.
6 Conclusion
In order to integrate, combine, process and analyze spatio-temporal data a
generic tracking framework for moving entities is proposed which is scale-independent
with regard to spatial and temporal resolution. It provides an additional benefit
to its users based upon spatio-temporal movement and behavior as it allows for
the establishment of location-based services. This framework analyzes spatio-
temporal data which is obtained from heterogeneous data sources. Furthermore,
this framework does not rely upon one tracking and localization system for the
data collection, but instead considers the combination of several systems as well
as the integration of proxy sensors, such as touch screens, with a fixed location
in an environment. The established tracking framework incorporates spatial lo-
cations and allows for reactive and device-oriented location-based services. This
framework can be applied to all kinds of collected spatio-temporal data, and
standardized interfaces make it possible to reuse it with different mobile sys-
tems which contributes to the filed of mobile computing.
References
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and Tracking System. In INFOCOM 2000. Nineteenth Annual Joint Conference of
the IEEE Computer and Communications Societies. Proceedings. IEEE, pages 775–
784, 2000.
2. C. Beder and M. Klepal. Fusing Location Data from Multiple Sensors: A Bench-
marking and Calibration Approach. In 2nd International Conference on Positioning
and Context-Awareness, 2011.
3. N. B. Priyantha, A. Chakraborty, and H. Balakrishnan. The Cricket Location-
Support System. In Proceedings of MOBICOM 2000, pages 32–43, Bosten, MA,
2000. ACM.