Proceedings of the 26th International Conference on Scientific and Statistical Database Management - SSDBM '14, 2014
ABSTRACT Hybrid data analysis systems integrate an analytic tool and a data management tool. Whil... more ABSTRACT Hybrid data analysis systems integrate an analytic tool and a data management tool. While hybrid systems have benefits, in order to be effective data movement between the two hybrid components must be minimized. Through experimental results we demonstrate that under workloads whose inputs vary in size, shape, and location, automation is the only practical way to manage data movement in hybrid systems.
Jessica Potter Department of Computer Science Portland State University PO Box 751 Portland, OR, ... more Jessica Potter Department of Computer Science Portland State University PO Box 751 Portland, OR, 97207-0751 Phone: 971-506-7687, Fax: 503-243-1934 Email: [email protected] ... Suman Tasmin Department of Civil and Environmental Engineering Portland State ...
Proceedings 14th International Conference on Data Engineering, 1998
... These techniques can indeed greatly improve relational performance for multi-dimensional quer... more ... These techniques can indeed greatly improve relational performance for multi-dimensional queries when ... deep hash joins for consolidation queries Su96 or B-tree indexes for star ... However, the recent emergence of object-relational database systems Ki95, St96 has opened the ...
Increased knowledge of truck travel patterns has the potential to increase overall highway safety... more Increased knowledge of truck travel patterns has the potential to increase overall highway safety, lead to better-managed maintenance operations, provide cost savings to public agencies, validate investments in intelligent transportation systems, and improve long-range planning and forecasting. This paper explores techniques that use current ITS technologies such as video image processing and loop detector data algorithms to collect and verify short and long vehicle count and length data. Three sets of traffic data for each time interval were created, and then compared using statistical analyses to produce results that that reveal some new information about the freight transportation system in the Portland metropolitan region.
Page 1. Low-latency Estimates for Window-Aggregate Queries over Data Streams by Amit Bhat A thesi... more Page 1. Low-latency Estimates for Window-Aggregate Queries over Data Streams by Amit Bhat A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in Computer Science Thesis Committee ...
The growth of the Internet has made it possible to query data in all corners of the globe. This t... more The growth of the Internet has made it possible to query data in all corners of the globe. This trend is being abetted by the emergence of standards for data representation, such as XML. In face of this exciting opportunity, however, there are several changes that need to be made to existing query engines to make them applicable for the task of querying the Internet. One of the challenges is providing partial results of query computation, based on the initial part of the input, because it may be undesirable to wait for all of the input. This is due to (a) limited data transfer bandwidth (b) temporary unavailability of sites and (c) intrinsically long-running queries (e.g., continual queries or triggers). A major issue in providing partial results is dealing with blocking operators, such as max, average, negation and nest. While previous work on producing partial results has looked at a limited set of blocking operators, emerging hierarchical standards such as XML, which are heavily nested, and sophisticated queries require more general solutions to the problem. In this paper, we define the semantics of partial results and outline mechanisms for ensuring these semantics for queries with arbitrary blocking operators. Re-architecting a query engine to produce partial results requires modifications to the runtime operators. We explore implementation alternatives and quantitatively compare their performance using our prototype system.
XML is fast emerging as the dominant standard for representing data in the World Wide Web. Sophis... more XML is fast emerging as the dominant standard for representing data in the World Wide Web. Sophisticated query engines that allow users to effectively tap the data stored in XML documents will be crucial to exploiting the full power of XML. While there has been a great deal of ...
The Portland Oregon Regional Transportation Archive Listing (PORTAL) is the official intelligent ... more The Portland Oregon Regional Transportation Archive Listing (PORTAL) is the official intelligent transportation systems data archive for the Portland metropolitan region. PORTAL has been archiving 20-second speed, count, and occupancy data from the approximately 500 inductive loop detectors in the Portland metropolitan region since July 2004. With a web-based interface, PORTAL provides performance metrics designed to assist practitioners and researchers. In order to provide accurate and useful information, it is essential that PORTAL process and maintain high-quality data, and further it is critical that users understand exactly how the data are processed. Users should also have a clear understanding of the quality of the data that they are viewing or extracting. There are several elements involved in maintaining quality data: effective allocation of maintenance resources for the inductive loop detectors, identification of suspect data values, and proper data aggregation. This paper presents a methodology for automatically detecting malfunctioning inductive loop detectors; describes how suspect data values are detected, handled, and reported in PORTAL; and finally describes PORTAL's data aggregation procedures. Examples of tools used to communicate data quality to PORTAL users are also provided.
Advanced Traveler Information Systems (ATIS) are integral components of Intelligent Transportatio... more Advanced Traveler Information Systems (ATIS) are integral components of Intelligent Transportation Systems (ITS). These systems are aimed at providing transportation system users with pre-trip or en-route travel information, thereby allowing travelers to make informed decisions about their travel choices. Most urban travel occurs on freeways; hence, the accurate prediction of travel time over freeway networks has become necessary. In order to develop benchmarks for improved travel time estimates in the Portland, Oregon (USA) metropolitan region, the objective of this paper is to evaluate several travel time algorithms using archived loop detector data and ground truth (probe vehicle) data.
Accurate travel time estimation has become possible with the deployment of advanced traveler mana... more Accurate travel time estimation has become possible with the deployment of advanced traveler management and information systems. Dynamic message signs, websites, and handheld/in-vehicle devices are being increasingly used by public agencies to communicate important travel information to the public such as incidents, road closures and travel times. Travel time estimates are usually derived from roadway sensors, although other technologies such as cell phone matching, license plate matching, automatic vehicle identification and video detection have also been employed. In Oregon, freeway travel time estimates are generated by the Oregon Department of Transportation using data from inductive loop detectors throughout the Portland metropolitan area. These estimates are generated using a simple midpoint algorithm that extrapolates measured speeds over a freeway segment. The objective of this paper is to evaluate the accuracy of the current midpoint algorithm by comparing the derived estimates to ground truth (probe vehicle) travel times. In addition, travel time estimates from a travel time algorithm developed by Coifman were also evaluated for accuracy under varying traffic conditions. Various scenarios were tested using traffic data from both upstream and downstream detector stations. The results indicate that both the midpoint and the Coifman algorithms generate accurate travel time estimates under free flow conditions. The Coifman algorithm using data from the upstream detector provided the best estimate of travel time for a link during congestion as well as in periods after an incident occurred. TRB 2007 Annual Meeting CD-ROM Paper revised from original submittal. Kothuri, Tufte, Ahn and Bertini TRB 2007 Annual Meeting CD-ROM Paper revised from original submittal. Kothuri, Tufte, Ahn and Bertini
Truck traffic on the nation's freeways is forecast to grow significantly in the near future. ... more Truck traffic on the nation's freeways is forecast to grow significantly in the near future. Managing the transportation system to ensure the efficient and reliable movement of trucks and the freight they carry is of vital importance. Knowledge of truck volume on freeway corridors will therefore be increasingly important. Until recently, classifying vehicles by their length was done using dual
The growth of the Internet has made it possible to query data in all corners of the globe. This t... more The growth of the Internet has made it possible to query data in all corners of the globe. This trend is being abetted by the emergence of standards for data representation, such as XML. In face of this exciting opportunity, however, there are several changes that need to be made to existing query engines to make them applicable for the task of querying the Internet. One of the challenges is providing partial results of query computation, based on the initial part of the input, because it may be undesirable to wait for all of the input. This is due to (a) limited data transfer bandwidth (b) temporary unavailability of sites and (c) intrinsically long-running queries (e.g., continual queries or triggers). A major issue in providing partial results is dealing with blocking operators, such as max, average, negation and nest. While previous work on producing partial results has looked at a limited set of blocking operators, emerging hierarchical standards such as XML, which are heavily nested, and sophisticated queries require more general solutions to the problem. In this paper, we define the semantics of partial results and outline mechanisms for ensuring these semantics for queries with arbitrary blocking operators. Re-architecting a query engine to produce partial results requires modifications to the runtime operators. We explore implementation alternatives and quantitatively compare their performance using our prototype system.
Proceedings of the 26th International Conference on Scientific and Statistical Database Management - SSDBM '14, 2014
ABSTRACT Hybrid data analysis systems integrate an analytic tool and a data management tool. Whil... more ABSTRACT Hybrid data analysis systems integrate an analytic tool and a data management tool. While hybrid systems have benefits, in order to be effective data movement between the two hybrid components must be minimized. Through experimental results we demonstrate that under workloads whose inputs vary in size, shape, and location, automation is the only practical way to manage data movement in hybrid systems.
Jessica Potter Department of Computer Science Portland State University PO Box 751 Portland, OR, ... more Jessica Potter Department of Computer Science Portland State University PO Box 751 Portland, OR, 97207-0751 Phone: 971-506-7687, Fax: 503-243-1934 Email: [email protected] ... Suman Tasmin Department of Civil and Environmental Engineering Portland State ...
Proceedings 14th International Conference on Data Engineering, 1998
... These techniques can indeed greatly improve relational performance for multi-dimensional quer... more ... These techniques can indeed greatly improve relational performance for multi-dimensional queries when ... deep hash joins for consolidation queries Su96 or B-tree indexes for star ... However, the recent emergence of object-relational database systems Ki95, St96 has opened the ...
Increased knowledge of truck travel patterns has the potential to increase overall highway safety... more Increased knowledge of truck travel patterns has the potential to increase overall highway safety, lead to better-managed maintenance operations, provide cost savings to public agencies, validate investments in intelligent transportation systems, and improve long-range planning and forecasting. This paper explores techniques that use current ITS technologies such as video image processing and loop detector data algorithms to collect and verify short and long vehicle count and length data. Three sets of traffic data for each time interval were created, and then compared using statistical analyses to produce results that that reveal some new information about the freight transportation system in the Portland metropolitan region.
Page 1. Low-latency Estimates for Window-Aggregate Queries over Data Streams by Amit Bhat A thesi... more Page 1. Low-latency Estimates for Window-Aggregate Queries over Data Streams by Amit Bhat A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in Computer Science Thesis Committee ...
The growth of the Internet has made it possible to query data in all corners of the globe. This t... more The growth of the Internet has made it possible to query data in all corners of the globe. This trend is being abetted by the emergence of standards for data representation, such as XML. In face of this exciting opportunity, however, there are several changes that need to be made to existing query engines to make them applicable for the task of querying the Internet. One of the challenges is providing partial results of query computation, based on the initial part of the input, because it may be undesirable to wait for all of the input. This is due to (a) limited data transfer bandwidth (b) temporary unavailability of sites and (c) intrinsically long-running queries (e.g., continual queries or triggers). A major issue in providing partial results is dealing with blocking operators, such as max, average, negation and nest. While previous work on producing partial results has looked at a limited set of blocking operators, emerging hierarchical standards such as XML, which are heavily nested, and sophisticated queries require more general solutions to the problem. In this paper, we define the semantics of partial results and outline mechanisms for ensuring these semantics for queries with arbitrary blocking operators. Re-architecting a query engine to produce partial results requires modifications to the runtime operators. We explore implementation alternatives and quantitatively compare their performance using our prototype system.
XML is fast emerging as the dominant standard for representing data in the World Wide Web. Sophis... more XML is fast emerging as the dominant standard for representing data in the World Wide Web. Sophisticated query engines that allow users to effectively tap the data stored in XML documents will be crucial to exploiting the full power of XML. While there has been a great deal of ...
The Portland Oregon Regional Transportation Archive Listing (PORTAL) is the official intelligent ... more The Portland Oregon Regional Transportation Archive Listing (PORTAL) is the official intelligent transportation systems data archive for the Portland metropolitan region. PORTAL has been archiving 20-second speed, count, and occupancy data from the approximately 500 inductive loop detectors in the Portland metropolitan region since July 2004. With a web-based interface, PORTAL provides performance metrics designed to assist practitioners and researchers. In order to provide accurate and useful information, it is essential that PORTAL process and maintain high-quality data, and further it is critical that users understand exactly how the data are processed. Users should also have a clear understanding of the quality of the data that they are viewing or extracting. There are several elements involved in maintaining quality data: effective allocation of maintenance resources for the inductive loop detectors, identification of suspect data values, and proper data aggregation. This paper presents a methodology for automatically detecting malfunctioning inductive loop detectors; describes how suspect data values are detected, handled, and reported in PORTAL; and finally describes PORTAL's data aggregation procedures. Examples of tools used to communicate data quality to PORTAL users are also provided.
Advanced Traveler Information Systems (ATIS) are integral components of Intelligent Transportatio... more Advanced Traveler Information Systems (ATIS) are integral components of Intelligent Transportation Systems (ITS). These systems are aimed at providing transportation system users with pre-trip or en-route travel information, thereby allowing travelers to make informed decisions about their travel choices. Most urban travel occurs on freeways; hence, the accurate prediction of travel time over freeway networks has become necessary. In order to develop benchmarks for improved travel time estimates in the Portland, Oregon (USA) metropolitan region, the objective of this paper is to evaluate several travel time algorithms using archived loop detector data and ground truth (probe vehicle) data.
Accurate travel time estimation has become possible with the deployment of advanced traveler mana... more Accurate travel time estimation has become possible with the deployment of advanced traveler management and information systems. Dynamic message signs, websites, and handheld/in-vehicle devices are being increasingly used by public agencies to communicate important travel information to the public such as incidents, road closures and travel times. Travel time estimates are usually derived from roadway sensors, although other technologies such as cell phone matching, license plate matching, automatic vehicle identification and video detection have also been employed. In Oregon, freeway travel time estimates are generated by the Oregon Department of Transportation using data from inductive loop detectors throughout the Portland metropolitan area. These estimates are generated using a simple midpoint algorithm that extrapolates measured speeds over a freeway segment. The objective of this paper is to evaluate the accuracy of the current midpoint algorithm by comparing the derived estimates to ground truth (probe vehicle) travel times. In addition, travel time estimates from a travel time algorithm developed by Coifman were also evaluated for accuracy under varying traffic conditions. Various scenarios were tested using traffic data from both upstream and downstream detector stations. The results indicate that both the midpoint and the Coifman algorithms generate accurate travel time estimates under free flow conditions. The Coifman algorithm using data from the upstream detector provided the best estimate of travel time for a link during congestion as well as in periods after an incident occurred. TRB 2007 Annual Meeting CD-ROM Paper revised from original submittal. Kothuri, Tufte, Ahn and Bertini TRB 2007 Annual Meeting CD-ROM Paper revised from original submittal. Kothuri, Tufte, Ahn and Bertini
Truck traffic on the nation's freeways is forecast to grow significantly in the near future. ... more Truck traffic on the nation's freeways is forecast to grow significantly in the near future. Managing the transportation system to ensure the efficient and reliable movement of trucks and the freight they carry is of vital importance. Knowledge of truck volume on freeway corridors will therefore be increasingly important. Until recently, classifying vehicles by their length was done using dual
The growth of the Internet has made it possible to query data in all corners of the globe. This t... more The growth of the Internet has made it possible to query data in all corners of the globe. This trend is being abetted by the emergence of standards for data representation, such as XML. In face of this exciting opportunity, however, there are several changes that need to be made to existing query engines to make them applicable for the task of querying the Internet. One of the challenges is providing partial results of query computation, based on the initial part of the input, because it may be undesirable to wait for all of the input. This is due to (a) limited data transfer bandwidth (b) temporary unavailability of sites and (c) intrinsically long-running queries (e.g., continual queries or triggers). A major issue in providing partial results is dealing with blocking operators, such as max, average, negation and nest. While previous work on producing partial results has looked at a limited set of blocking operators, emerging hierarchical standards such as XML, which are heavily nested, and sophisticated queries require more general solutions to the problem. In this paper, we define the semantics of partial results and outline mechanisms for ensuring these semantics for queries with arbitrary blocking operators. Re-architecting a query engine to produce partial results requires modifications to the runtime operators. We explore implementation alternatives and quantitatively compare their performance using our prototype system.
Over the last decade, there has been a push towards the development and deployment of Intelligent... more Over the last decade, there has been a push towards the development and deployment of Intelligent Transportation Systems (ITS) because of the many benefits that these systems can provide. One of the important components of ITS is Advanced Traveler Information Systems (ATIS). These systems aim to provide the users with pre-trip or en route travel information so that users can
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