Proceedings of the 2010 International Conference on E-Business Intelligence, 2010
In this research, we developed a design framework for systems supporting online discussion speech... more In this research, we developed a design framework for systems supporting online discussion speech act analysis and situation profiling. The framework advocates the development of systems that support all three facets of online discussion situation profiling: snapshot, duration, and people. The framework also provides guidelines for the creation of speech act category, the choice of appropriate classification algorithms, features, and feature selection techniques necessary to effectively identify the roles each message plays, and the topic categorization of discussion text.
Proceedings 12th IEEE Internationals Conference on Tools with Artificial Intelligence. ICTAI 2000
In this paper, we address the problem of consistency checking for Euclidean spatial constraints. ... more In this paper, we address the problem of consistency checking for Euclidean spatial constraints. A dimension graph representation is proposed to maintain the Euclidean spatial constraints among objects. The basic idea is to project the spatial constraints on both X and Y dimensions, and the dimension graph is constructed on each dimension. By using the dimension graph representation, the problem of consistency checking is then transformed to a graph cycle detection problem. The consistency checking can be achieved with O(N+E) time as well as space complexity, where N is the number of spatial objects, and E is the number of spatial predicates in the constraint. The proposed approach to consistency checking for spatial constraints is faster than O(N 2) when the number of predicates is much smaller than N 2 and there are few disjunctions in the spatial constraint. The dimension graph and consistency checking algorithm can be used for points, intervals and polygons in 2 dimensional space. The algorithm can guarantee the global consistency.
Proceedings of the 6th ACM international symposium on Advances in geographic information systems, 1998
Direction is an important spatial relationship that is used in many fields such as geographic inf... more Direction is an important spatial relationship that is used in many fields such as geographic information systems(GIS) and image interpretation. It is also frequently used as a selection condition in spatial queries. Previous-work has modeled direction as a relationship predicate between spatial objects. Conversely, in this paper, we model **ion as a new kind of spatial object using the concepts of vec-tOX-S, points ad angles. The basic approach is to model direction as a unit vector. Gkwn an ordered pair (P1,P2) of spatial points, one can define a direction, which can take the values of N'orth, Northwest, 3 o'clock, etc. to represent the corresponding qualitative directional predicates on (P1,P2) in previous work. Direction objects can also have quantitative operations such as direction-composition and direction-reverse. This novel tie-w of direction has several obvious advantages First, it allows us to deiine the orientation of spatial object% Second, a richer set of predicates and operators on direction and orientation can be define~Third, new spatial data~TPessuch as oriented spatial objects and unbounded spatial objects can be defined-Finally, the object view of direction makes it easy to do direction reasoning, which is useful in spatial query processing and optimization-Key-worck Dwection, Orientatio~unbounded object, oriented spatial object. Computing Research Center under the auspices of the Department of the .kw, AmY Research Laboratory~oper'ati~re asreemmt n~ber DAAI%04-9S-2-0003/contract number DA.AH04-95-GOO08, the content of whkb does not necessarily reflect the position or the policy of the government, and no official endorsement should be inferred. This work was afso supported in part by NSF grant #9631539. Perm'k+sionto make dig"til or hard copies of all or pan of this work for personal or classroom use is granted W-hhcut fee provided that copies are not made or ddbuted for profn or commercial advanTage and zhst copiss bear this notice and the full c-mtion on the first page. To copy otherwse, torepubfiih, to post on sewers or to reddbme to Ms. requires prior specific permission andhx a fee. ACM GIS .
Direction is an important spatial concept that is used in many fields such as geographic informat... more Direction is an important spatial concept that is used in many fields such as geographic information systems(GIS) and image interpretation. It is also frequently used as a selection condition in spatial queries. Previous work has modeled direction as a relational predicate between spatial objects. Conversely, in this paper, we model direction as a new kind of spatial object using the concepts of vectors, points and angles. The basic approach is to model direction as a unit vector. This novel view of direction has several obvious advantages: Being modeled as a spatial object, a direction object can have its own attributes and operation set. Secondly, new spatial data types such as oriented spatial objects and open spatial objects can be defined at the abstract object level. Finally, the object view of direction makes direction reasoning easy and also reduces the need for a large number of inference rules. These features are important in spatial query processing and optimization. The ...
Proceedings of the 8th ACM international symposium on Advances in geographic information systems, 2000
Direction based spatial relationships are critical in many domains including geographic informati... more Direction based spatial relationships are critical in many domains including geographic information systems(GIS) and image interpretation. They are also frequently used as selection conditions in spatial queries. In this paper, we explore the processing of queries based on object-orientation-based directional relationships. A new open shape based strategy(OSS) is proposed. OSS converts the processing of the direction predicates to the processing of topological operations between open shapes and closed geometry objects. Since OSS models the direction region as an OpenShape, it does not need to know the boundary of the embedding world, and also eliminating the computation related to the world boundary. The experimental evaluations show that OSS consistently outperforms classical range query strategy both in I/O and CPU cost. This paper is a summary of the results.
Automotive telematics may be defined as the information-intensive applications enabled for vehicl... more Automotive telematics may be defined as the information-intensive applications enabled for vehicles by a combination of telecommunications and computing technology. Telematics by its nature requires the capture, storage, and exchange of sensor data to obtain remote services. Such data likely include personal, sensitive information, which require proper handling to protect the driver's privacy. Some existing approaches focus on protecting privacy through anonymous interactions or by stopping information flow altogether. We complement these by concentrating instead on giving different stakeholders control over data sharing and use. In this paper, we identify several data protection challenges specifically related to the automotive telematics domain, and propose a general data protection framework to address some of those challenges. The framework enables data aggregation before data is released to service providers, which minimizes the disclosure of privacy sensitive information. We have implemented the core component, the privacy engine, to help users manage their privacy policies and to authorize data requests based on policy matching. The policy manager provides a flexible privacy policy model that allows data subjects to express rich constraint-based policies, including eventbased, and spatio-temporal constraints. Thus, the policy engine can decide on a large number of requests without user assistance and causes no interruptions while driving. A performance study indicates that the overhead is stable with an increasing number of data subjects.
Recently, several techniques have been proposed to protect the user location privacy for location... more Recently, several techniques have been proposed to protect the user location privacy for location-based services in the Euclidean space. Applying these techniques directly to the road network environment would lead to privacy leakage and inefficient query processing. In this paper, we propose a new location anonymization algorithm that is designed specifically for the road network environment. Our algorithm relies on the commonly used concept of spatial cloaking, where a user location is cloaked into a set of connected road segments of a minimum total length L including at least K users. Our algorithm is "query-aware" as it takes into account the query execution cost at a database server and the query quality, i.e., the number of objects returned to users by the database server, during the location anonymization process. In particular, we develop a new cost function that balances between the query execution cost and the query quality. Then, we introduce two versions of our algorithm, namely, pure greedy and randomized greedy, that aim to minimize the developed cost function and satisfy the user specified privacy requirements. To accommodate intervals with a high workload, we introduce a shared execution paradigm that boosts the scalability of our location anonymization algorithm and the database server to support large numbers of queries received in a short time period. Extensive experimental results show that
Proceedings of the 2nd international workshop on Mobile commerce - WMC '02, 2002
Automotive telematics may be defined as the informationintensive applications that are being enab... more Automotive telematics may be defined as the informationintensive applications that are being enabled for vehicles by a combination of telecommunications and computing technology. Telematics by its nature requires the capture of sensor data, storage and exchange of data to obtain remote services. In order for automotive telematics to grow to its full potential, telematics data must be protected. Data protection must include privacy and security for end-users, service providers and application providers. In this paper, we propose a new framework for data protection that is built on the foundation of privacy and security technologies. The privacy technology enables users and service providers to define flexible data model and policy models. The security technology provides traditional capabilities such as encryption, authentication, non-repudiation. In addition, it provides secure environments for protected execution, which is essential to limiting data access to specific purposes.
Proceedings of the 14th annual ACM international symposium on Advances in geographic information systems - GIS '06, 2006
This paper tackles a major privacy threat in current location-based services where users have to ... more This paper tackles a major privacy threat in current location-based services where users have to report their exact locations to the database server in order to obtain their desired services. For example, a mobile user asking about her nearest restaurant has to report her exact location. With untrusted service providers, reporting private location information may lead to several privacy threats. In this paper, we present a peer-to-peer (P2P) spatial cloaking algorithm in which mobile and stationary users can entertain location-based services without revealing their exact location information. The main idea is that before requesting any location-based service, the mobile user will form a group from her peers via single-hop communication and/or multihop routing. Then, the spatial cloaked area is computed as the region that covers the entire group of peers. Two modes of operations are supported within the proposed P2P spatial cloaking algorithm, namely, the on-demand mode and the proactive mode. Experimental results show that the P2P spatial cloaking algorithm operated in the on-demand mode has lower communication cost and better quality of services than the proactive mode, but the on-demand incurs longer response time.
Satisfying the varied privacy preferences of individuals, while exposing context data to authoriz... more Satisfying the varied privacy preferences of individuals, while exposing context data to authorized applications and individuals, remains a major challenge for context-aware computing. This paper describes our experiences in building a middleware component, the Context Privacy Engine (CPE), that enforces a role-based, context-dependent privacy model for enterprise domains. While fundamentally an ACL-based access control scheme, CPE extends the traditional ACL mechanism with usage control and context constraints. This paper focuses on discussing issues related to managing and evaluating contextdependent privacy policies. Extensive experimental studies with a production-grade implementation and real-life context sources demonstrate that the CPE can support a large number of concurrent requests. The experiments also show valuable insight on how context-retrieval can affect the privacy evaluation process.
Spatial databases, addressing the growing data management and analysis needs of spatial applicati... more Spatial databases, addressing the growing data management and analysis needs of spatial applications such as Geographic Information Systems, have been an active area of research for more than two decades. This research has produced a taxonomy of models for space, spatial data types and operators, spatial query languages and processing strategies, as well as spatial indexes and clustering techniques. However, more research is needed to improve support for network and field data, as well as query processing (e.g., cost models, bulk load). Another important need is to apply spatial data management accomplishments to newer applications, such as data warehouses and multimedia information systems. The objective of this paper is to identify recent accomplishments and associated research needs of the near term.
Spatial databases, addressing the growing data management and analysis needs of spatial applicati... more Spatial databases, addressing the growing data management and analysis needs of spatial applications such as Geographic Information Systems, have been an active area of research for more than two decades. This research has produced a taxonomy of models for space, spatial data types and operators, spatial query languages and processing strategies, as well as spatial indexes and clustering techniques. However, more research is needed to improve support for network and field data, as well as query processing (e.g., cost models, bulk load). Another important need is to apply spatial data management accomplishments to newer applications, such as data warehouses and multimedia information systems. The objective of this paper is to identify recent accomplishments and associated research needs of the near term.
This paper tackles a privacy breach in current location-based services (LBS) where mobile users h... more This paper tackles a privacy breach in current location-based services (LBS) where mobile users have to report their exact location information to an LBS provider in order to obtain their desired services. For example, a user who wants to issue a query asking about her nearest gas station has to report her exact location to an LBS provider. However, many
Proceedings of the 2010 International Conference on E-Business Intelligence, 2010
In this research, we developed a design framework for systems supporting online discussion speech... more In this research, we developed a design framework for systems supporting online discussion speech act analysis and situation profiling. The framework advocates the development of systems that support all three facets of online discussion situation profiling: snapshot, duration, and people. The framework also provides guidelines for the creation of speech act category, the choice of appropriate classification algorithms, features, and feature selection techniques necessary to effectively identify the roles each message plays, and the topic categorization of discussion text.
Proceedings 12th IEEE Internationals Conference on Tools with Artificial Intelligence. ICTAI 2000
In this paper, we address the problem of consistency checking for Euclidean spatial constraints. ... more In this paper, we address the problem of consistency checking for Euclidean spatial constraints. A dimension graph representation is proposed to maintain the Euclidean spatial constraints among objects. The basic idea is to project the spatial constraints on both X and Y dimensions, and the dimension graph is constructed on each dimension. By using the dimension graph representation, the problem of consistency checking is then transformed to a graph cycle detection problem. The consistency checking can be achieved with O(N+E) time as well as space complexity, where N is the number of spatial objects, and E is the number of spatial predicates in the constraint. The proposed approach to consistency checking for spatial constraints is faster than O(N 2) when the number of predicates is much smaller than N 2 and there are few disjunctions in the spatial constraint. The dimension graph and consistency checking algorithm can be used for points, intervals and polygons in 2 dimensional space. The algorithm can guarantee the global consistency.
Proceedings of the 6th ACM international symposium on Advances in geographic information systems, 1998
Direction is an important spatial relationship that is used in many fields such as geographic inf... more Direction is an important spatial relationship that is used in many fields such as geographic information systems(GIS) and image interpretation. It is also frequently used as a selection condition in spatial queries. Previous-work has modeled direction as a relationship predicate between spatial objects. Conversely, in this paper, we model **ion as a new kind of spatial object using the concepts of vec-tOX-S, points ad angles. The basic approach is to model direction as a unit vector. Gkwn an ordered pair (P1,P2) of spatial points, one can define a direction, which can take the values of N'orth, Northwest, 3 o'clock, etc. to represent the corresponding qualitative directional predicates on (P1,P2) in previous work. Direction objects can also have quantitative operations such as direction-composition and direction-reverse. This novel tie-w of direction has several obvious advantages First, it allows us to deiine the orientation of spatial object% Second, a richer set of predicates and operators on direction and orientation can be define~Third, new spatial data~TPessuch as oriented spatial objects and unbounded spatial objects can be defined-Finally, the object view of direction makes it easy to do direction reasoning, which is useful in spatial query processing and optimization-Key-worck Dwection, Orientatio~unbounded object, oriented spatial object. Computing Research Center under the auspices of the Department of the .kw, AmY Research Laboratory~oper'ati~re asreemmt n~ber DAAI%04-9S-2-0003/contract number DA.AH04-95-GOO08, the content of whkb does not necessarily reflect the position or the policy of the government, and no official endorsement should be inferred. This work was afso supported in part by NSF grant #9631539. Perm'k+sionto make dig"til or hard copies of all or pan of this work for personal or classroom use is granted W-hhcut fee provided that copies are not made or ddbuted for profn or commercial advanTage and zhst copiss bear this notice and the full c-mtion on the first page. To copy otherwse, torepubfiih, to post on sewers or to reddbme to Ms. requires prior specific permission andhx a fee. ACM GIS .
Direction is an important spatial concept that is used in many fields such as geographic informat... more Direction is an important spatial concept that is used in many fields such as geographic information systems(GIS) and image interpretation. It is also frequently used as a selection condition in spatial queries. Previous work has modeled direction as a relational predicate between spatial objects. Conversely, in this paper, we model direction as a new kind of spatial object using the concepts of vectors, points and angles. The basic approach is to model direction as a unit vector. This novel view of direction has several obvious advantages: Being modeled as a spatial object, a direction object can have its own attributes and operation set. Secondly, new spatial data types such as oriented spatial objects and open spatial objects can be defined at the abstract object level. Finally, the object view of direction makes direction reasoning easy and also reduces the need for a large number of inference rules. These features are important in spatial query processing and optimization. The ...
Proceedings of the 8th ACM international symposium on Advances in geographic information systems, 2000
Direction based spatial relationships are critical in many domains including geographic informati... more Direction based spatial relationships are critical in many domains including geographic information systems(GIS) and image interpretation. They are also frequently used as selection conditions in spatial queries. In this paper, we explore the processing of queries based on object-orientation-based directional relationships. A new open shape based strategy(OSS) is proposed. OSS converts the processing of the direction predicates to the processing of topological operations between open shapes and closed geometry objects. Since OSS models the direction region as an OpenShape, it does not need to know the boundary of the embedding world, and also eliminating the computation related to the world boundary. The experimental evaluations show that OSS consistently outperforms classical range query strategy both in I/O and CPU cost. This paper is a summary of the results.
Automotive telematics may be defined as the information-intensive applications enabled for vehicl... more Automotive telematics may be defined as the information-intensive applications enabled for vehicles by a combination of telecommunications and computing technology. Telematics by its nature requires the capture, storage, and exchange of sensor data to obtain remote services. Such data likely include personal, sensitive information, which require proper handling to protect the driver's privacy. Some existing approaches focus on protecting privacy through anonymous interactions or by stopping information flow altogether. We complement these by concentrating instead on giving different stakeholders control over data sharing and use. In this paper, we identify several data protection challenges specifically related to the automotive telematics domain, and propose a general data protection framework to address some of those challenges. The framework enables data aggregation before data is released to service providers, which minimizes the disclosure of privacy sensitive information. We have implemented the core component, the privacy engine, to help users manage their privacy policies and to authorize data requests based on policy matching. The policy manager provides a flexible privacy policy model that allows data subjects to express rich constraint-based policies, including eventbased, and spatio-temporal constraints. Thus, the policy engine can decide on a large number of requests without user assistance and causes no interruptions while driving. A performance study indicates that the overhead is stable with an increasing number of data subjects.
Recently, several techniques have been proposed to protect the user location privacy for location... more Recently, several techniques have been proposed to protect the user location privacy for location-based services in the Euclidean space. Applying these techniques directly to the road network environment would lead to privacy leakage and inefficient query processing. In this paper, we propose a new location anonymization algorithm that is designed specifically for the road network environment. Our algorithm relies on the commonly used concept of spatial cloaking, where a user location is cloaked into a set of connected road segments of a minimum total length L including at least K users. Our algorithm is "query-aware" as it takes into account the query execution cost at a database server and the query quality, i.e., the number of objects returned to users by the database server, during the location anonymization process. In particular, we develop a new cost function that balances between the query execution cost and the query quality. Then, we introduce two versions of our algorithm, namely, pure greedy and randomized greedy, that aim to minimize the developed cost function and satisfy the user specified privacy requirements. To accommodate intervals with a high workload, we introduce a shared execution paradigm that boosts the scalability of our location anonymization algorithm and the database server to support large numbers of queries received in a short time period. Extensive experimental results show that
Proceedings of the 2nd international workshop on Mobile commerce - WMC '02, 2002
Automotive telematics may be defined as the informationintensive applications that are being enab... more Automotive telematics may be defined as the informationintensive applications that are being enabled for vehicles by a combination of telecommunications and computing technology. Telematics by its nature requires the capture of sensor data, storage and exchange of data to obtain remote services. In order for automotive telematics to grow to its full potential, telematics data must be protected. Data protection must include privacy and security for end-users, service providers and application providers. In this paper, we propose a new framework for data protection that is built on the foundation of privacy and security technologies. The privacy technology enables users and service providers to define flexible data model and policy models. The security technology provides traditional capabilities such as encryption, authentication, non-repudiation. In addition, it provides secure environments for protected execution, which is essential to limiting data access to specific purposes.
Proceedings of the 14th annual ACM international symposium on Advances in geographic information systems - GIS '06, 2006
This paper tackles a major privacy threat in current location-based services where users have to ... more This paper tackles a major privacy threat in current location-based services where users have to report their exact locations to the database server in order to obtain their desired services. For example, a mobile user asking about her nearest restaurant has to report her exact location. With untrusted service providers, reporting private location information may lead to several privacy threats. In this paper, we present a peer-to-peer (P2P) spatial cloaking algorithm in which mobile and stationary users can entertain location-based services without revealing their exact location information. The main idea is that before requesting any location-based service, the mobile user will form a group from her peers via single-hop communication and/or multihop routing. Then, the spatial cloaked area is computed as the region that covers the entire group of peers. Two modes of operations are supported within the proposed P2P spatial cloaking algorithm, namely, the on-demand mode and the proactive mode. Experimental results show that the P2P spatial cloaking algorithm operated in the on-demand mode has lower communication cost and better quality of services than the proactive mode, but the on-demand incurs longer response time.
Satisfying the varied privacy preferences of individuals, while exposing context data to authoriz... more Satisfying the varied privacy preferences of individuals, while exposing context data to authorized applications and individuals, remains a major challenge for context-aware computing. This paper describes our experiences in building a middleware component, the Context Privacy Engine (CPE), that enforces a role-based, context-dependent privacy model for enterprise domains. While fundamentally an ACL-based access control scheme, CPE extends the traditional ACL mechanism with usage control and context constraints. This paper focuses on discussing issues related to managing and evaluating contextdependent privacy policies. Extensive experimental studies with a production-grade implementation and real-life context sources demonstrate that the CPE can support a large number of concurrent requests. The experiments also show valuable insight on how context-retrieval can affect the privacy evaluation process.
Spatial databases, addressing the growing data management and analysis needs of spatial applicati... more Spatial databases, addressing the growing data management and analysis needs of spatial applications such as Geographic Information Systems, have been an active area of research for more than two decades. This research has produced a taxonomy of models for space, spatial data types and operators, spatial query languages and processing strategies, as well as spatial indexes and clustering techniques. However, more research is needed to improve support for network and field data, as well as query processing (e.g., cost models, bulk load). Another important need is to apply spatial data management accomplishments to newer applications, such as data warehouses and multimedia information systems. The objective of this paper is to identify recent accomplishments and associated research needs of the near term.
Spatial databases, addressing the growing data management and analysis needs of spatial applicati... more Spatial databases, addressing the growing data management and analysis needs of spatial applications such as Geographic Information Systems, have been an active area of research for more than two decades. This research has produced a taxonomy of models for space, spatial data types and operators, spatial query languages and processing strategies, as well as spatial indexes and clustering techniques. However, more research is needed to improve support for network and field data, as well as query processing (e.g., cost models, bulk load). Another important need is to apply spatial data management accomplishments to newer applications, such as data warehouses and multimedia information systems. The objective of this paper is to identify recent accomplishments and associated research needs of the near term.
This paper tackles a privacy breach in current location-based services (LBS) where mobile users h... more This paper tackles a privacy breach in current location-based services (LBS) where mobile users have to report their exact location information to an LBS provider in order to obtain their desired services. For example, a user who wants to issue a query asking about her nearest gas station has to report her exact location to an LBS provider. However, many
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