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University of Alabama

1. Wang, Mengxiao. Queue predictions at temporary work zones: modification and testing of an existing spreadsheet.

Degree: 2010, University of Alabama

URL: http://purl.lib.ua.edu/13853 

At the Alabama Department of Transportation (ALDOT), the tool used by traffic engineers to predict whether a queue will form at a freeway work zone is the Excel-based "Lane Rental Model" developed at the Oklahoma Department of Transportation (OkDOT) and whose work zone flow capacity values are based on the 1994 Highway Capacity Manual (HCM, 1994). The scope of this research pertains only to the queue estimation worksheet of that spreadsheet tool, herein referred to as the OkDOT baseline version. This tool, based on input-output logic, is simple to understand and use. Preliminary testing of the OkDOT baseline spreadsheet confirmed a lack of accuracy, and an opportunity to update the capacity estimation method while keeping the rest of the tool intact. Two other versions were created using the work zone lane capacity model of HCM 2000: the HCM 2000 version uses work zone intensity effects of -160 to +160 passenger cars per hour per lane (pcphpl), as prescribed in HCM 2000; the second modified version uses work zone intensity penalties of -500 to 0 pcphpl, a modification based on recent literature, and is, therefore, called the HCM 2000 hybrid version. Although work zone capacity estimation has been widely researched over the past three decades, only a few studies measured actual queue start times, queue lengths (hence maximum queue length); almost all utilize the free flow traffic volume approaching the work zone and predict the capacity of the work zone (rate of traffic exiting the downstream end of the work zone). One in particular (Sarasua et al. 2006) collected extensive data on lane capacity and queue characteristics (if a queue formed) at 35 freeway work zones in South Carolina. We use 32 of these work zone descriptions as the "test data bank" for comparing predictions produced by three versions of the OkDOT spreadsheet tool with the actual maximum queue length (MQL) and queue start time (QST). Minimizing the prediction error in MQL is the main criterion for comparing the accuracy of the three OkDOT model versions, though QST was also considered. Based on the analysis and evaluation, the strong conclusion is that the current tool should be replaced by the HCM 2000 hybrid version we have developed and tested. The HCM hybrid version minimized error in predicting actual MQL at the 32 SC work zones, and minimized the error of not predicting a queue, when one actually formed. Additional testing revealed that a passenger car equivalent PCE = 2.1 for heavy vehicles minimized error in MQL among typical PCE values in the range [2.0, 2.5]. This tool was validated using six work zone cases, three from Alabama and three from North Carolina. In addition to modification of the capacity estimation method in the OkDOT tool, we endeavored to make it more useful for mobility impact assessment by including a graphical depiction of the queue profile. A CD with the HCM 2000 hybrid version of the software was delivered to ALDOT with a final report. A detailed user's guide was prepared and is included as an appendix to this thesis.… Advisors/Committee Members: Batson, Robert G., Fonseca, Daniel J., Ray, Paul S., University of Alabama. Dept. of Civil, Construction, and Environmental Engineering.

Subjects/Keywords: Electronic Thesis or Dissertation;  – thesis; Transportation; Engineering, Civil; lane closure; maximum queue length; queue prediction; queue start time; work zone; work zone capacity

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Wang, M. (2010). Queue predictions at temporary work zones: modification and testing of an existing spreadsheet. (Thesis). University of Alabama. Retrieved from http://purl.lib.ua.edu/13853

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16th Edition):

Wang, Mengxiao. “Queue predictions at temporary work zones: modification and testing of an existing spreadsheet.” 2010. Thesis, University of Alabama. Accessed March 05, 2021. http://purl.lib.ua.edu/13853.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7th Edition):

Wang, Mengxiao. “Queue predictions at temporary work zones: modification and testing of an existing spreadsheet.” 2010. Web. 05 Mar 2021.

Vancouver:

Wang M. Queue predictions at temporary work zones: modification and testing of an existing spreadsheet. [Internet] [Thesis]. University of Alabama; 2010. [cited 2021 Mar 05]. Available from: http://purl.lib.ua.edu/13853.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Wang M. Queue predictions at temporary work zones: modification and testing of an existing spreadsheet. [Thesis]. University of Alabama; 2010. Available from: http://purl.lib.ua.edu/13853

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation


University of Texas – Austin

2. Ellis, Apollo Isaac Orion. Jack Rabbit : an effective Cell BE programming system for high performance parallelism.

Degree: MSin Computer Sciences, Computer Science, 2011, University of Texas – Austin

URL: http://hdl.handle.net/2152/ETD-UT-2011-05-3624 

The Cell processor is an example of the trade-offs made when designing a mass market power efficient multi-core machine, but the machine-exposing architecture and raw communication mechanisms of Cell are hard to manage for a programmer. Cell's design is simple and causes software complexity to go up in the areas of achieving low threading overhead, good bandwidth efficiency, and load balance. Several attempts have been made to produce efficient and effective programming systems for Cell, but the attempts have been too specialized and thus fall short. We present Jack Rabbit, an efficient thread pool work queue implementation, with load balancing mechanisms and double buffering. Our system incurs low threading overhead, gets good load balance, and achieves bandwidth efficiency. Our system represents a step towards an effective way to program Cell and any similar current or future processors. Advisors/Committee Members: Lin, Yun Calvin (advisor), Fussell, Donald S., 1951- (advisor).

Subjects/Keywords: Cell processor; Parallel processing (Electronic computers); Multi-core systems; High performance computing; Runtime; Barnes Hut; LU factorization; Mandelbrot; Double buffering; Thread pool; Work queue; Load balance

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Ellis, A. I. O. (2011). Jack Rabbit : an effective Cell BE programming system for high performance parallelism. (Masters Thesis). University of Texas – Austin. Retrieved from http://hdl.handle.net/2152/ETD-UT-2011-05-3624

Chicago Manual of Style (16th Edition):

Ellis, Apollo Isaac Orion. “Jack Rabbit : an effective Cell BE programming system for high performance parallelism.” 2011. Masters Thesis, University of Texas – Austin. Accessed March 05, 2021. http://hdl.handle.net/2152/ETD-UT-2011-05-3624.

MLA Handbook (7th Edition):

Ellis, Apollo Isaac Orion. “Jack Rabbit : an effective Cell BE programming system for high performance parallelism.” 2011. Web. 05 Mar 2021.

Vancouver:

Ellis AIO. Jack Rabbit : an effective Cell BE programming system for high performance parallelism. [Internet] [Masters thesis]. University of Texas – Austin; 2011. [cited 2021 Mar 05]. Available from: http://hdl.handle.net/2152/ETD-UT-2011-05-3624.

Council of Science Editors:

Ellis AIO. Jack Rabbit : an effective Cell BE programming system for high performance parallelism. [Masters Thesis]. University of Texas – Austin; 2011. Available from: http://hdl.handle.net/2152/ETD-UT-2011-05-3624

3. Shrestha, Sajan. SENSITIVITY OF QUEUE ESTIMATES TO THE SIZE OF THE TIME INTERVAL USED TO AGGREGATE TRAFFIC VOLUME DATA.

Degree: MSin Civil Engineering, Washkewicz College of Engineering, 2015, Cleveland State University

URL: http://rave.ohiolink.edu/etdc/view?acc_num=csu1431087335 

To facilitate construction and maintenance activities on freeways, a common practice is to close a lane of traffic. The lane closure affords the work crew space to work, as well as providing access to the work site and even providing a buffer between the work activities and the traffic. However, closing a lane can have an impact on the traffic flow and cause delays to the traveling public and movement of goods. If the traffic flow is greater than that which can be serviced by the lanes which remain open, then traffic backs up, or queues. A good estimate of the number of vehicles that will queue is needed to make informed decisions about when lanes can be closed, and how many lanes can be closed, while minimizing the impact on traffic. The Highway Capacity Manual provides a recommended methodology to analyze freeway operations. The methodology uses a 15 minute time interval for analysis but recommends a much small interval such as 15 to 60 seconds to analyze a queued condition. In contrast, sketch planning tools used by state departments of transportation to analyze queuing typically use an hour interval with hourly traffic volumes. Both the HCM methodology and the sketch planning tools compare the number vehicles arriving to the maximum number of vehicles that can be serviced over a period of time. Therefore, the queue estimate relies on having a good estimate of the capacity of the work zone with the lane closure as well as good traffic volume data. The purpose of this thesis was to examine the sensitivity of queue estimates to the size of the time interval used to aggregate traffic volumes. When the traffic volumes are aggregated into small time intervals, the variability of the flow is better captured than when large time intervals are used. Therefore, it was expected that queue estimates would improve when smaller time intervals were used. To examine this relationship, field studies and a sensitivity analysis were conducted. The field studies were conducted at two Ohio work zones. At a work zone on I-71 in Columbus, 2 of 3 traffic lanes were closed. At a work zone on I-75 in Dayton, 1 of 3 traffic lanes was closed. Traffic volumes and queueing data were collected. The traffic volume data was aggregated using 5, 10, 15, 20 and 30 minute intervals and used to estimate the number of vehicles in the queue. The sensitivity of this queue estimate to the time interval used for aggregation was examined. The results of the sensitivity analysis were as expected. Regardless of the time interval used for aggregation, the queue is considered to have a constant growth rate between estimates. This means that when larger time intervals are used for aggregation, more details about the variability of the traffic flow are lost and the queue estimate between within each time interval includes an aggregation error. Although the 5 minute time intervals would provide the best detail about the formation of the queue, the sketch planning tools and the traffic data themselves are usually based on hourly volumes. The hourly volumes are… Advisors/Committee Members: Jenkins, Jacqueline M (Advisor).

Subjects/Keywords: Civil Engineering; Transportation Planning; Small time interval volume count, Sensitivity of Queue, Peak hour factor, variability of flow, Work zone capacity, Deterministic Queue

…includes estimating the capacity of freeway work zones with lane closures and the resulting queue… …Queue analysis for short term work zone lane closures relies heavily on the capacity estimate… …21 3.2 Work Zone Lane Closure Sites… …28 4.1 Deterministic Queue Analysis… …28 4.1.1 Site 1 Queue Analysis… 

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Shrestha, S. (2015). SENSITIVITY OF QUEUE ESTIMATES TO THE SIZE OF THE TIME INTERVAL USED TO AGGREGATE TRAFFIC VOLUME DATA. (Masters Thesis). Cleveland State University. Retrieved from http://rave.ohiolink.edu/etdc/view?acc_num=csu1431087335

Chicago Manual of Style (16th Edition):

Shrestha, Sajan. “SENSITIVITY OF QUEUE ESTIMATES TO THE SIZE OF THE TIME INTERVAL USED TO AGGREGATE TRAFFIC VOLUME DATA.” 2015. Masters Thesis, Cleveland State University. Accessed March 05, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=csu1431087335.

MLA Handbook (7th Edition):

Shrestha, Sajan. “SENSITIVITY OF QUEUE ESTIMATES TO THE SIZE OF THE TIME INTERVAL USED TO AGGREGATE TRAFFIC VOLUME DATA.” 2015. Web. 05 Mar 2021.

Vancouver:

Shrestha S. SENSITIVITY OF QUEUE ESTIMATES TO THE SIZE OF THE TIME INTERVAL USED TO AGGREGATE TRAFFIC VOLUME DATA. [Internet] [Masters thesis]. Cleveland State University; 2015. [cited 2021 Mar 05]. Available from: http://rave.ohiolink.edu/etdc/view?acc_num=csu1431087335.

Council of Science Editors:

Shrestha S. SENSITIVITY OF QUEUE ESTIMATES TO THE SIZE OF THE TIME INTERVAL USED TO AGGREGATE TRAFFIC VOLUME DATA. [Masters Thesis]. Cleveland State University; 2015. Available from: http://rave.ohiolink.edu/etdc/view?acc_num=csu1431087335

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