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University of Nebraska - Lincoln

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Articles 391 - 420 of 436

Full-Text Articles in Civil Engineering

Pilot Study On Real-Time Calculation Of Arrival Type For Assessment Of Arterial Performance, Edward J. Smaglik, Darcy M. Bullock, Anuj Sharma Jul 2007

Pilot Study On Real-Time Calculation Of Arrival Type For Assessment Of Arterial Performance, Edward J. Smaglik, Darcy M. Bullock, Anuj Sharma

Department of Civil and Environmental Engineering: Faculty Publications

The Highway Capacity Manual uses the arrival type (AT) as a mechanism to account for the quality of traffic signal coordination in the calculation of delay at a signalized intersection. Although there is much discussion in the literature regarding the accuracy and precision of this approach, the AT parameter provides a simple mechanism for grading the performance of traffic signal coordination. This paper describes data collection limitations of current traffic signal controllers and proposes a procedure where the AT parameter can be calculated by traffic signal controllers in real time. Given that the nation received a score of 61 out …


Traffic Noise Barrier System: U.S. Patent No. Us 7,220,077 B2, Eric C. Humphries, Stephen D. Barratt, Ronald K. Faller, Keith J. Kurz, Dean L. Sicking May 2007

Traffic Noise Barrier System: U.S. Patent No. Us 7,220,077 B2, Eric C. Humphries, Stephen D. Barratt, Ronald K. Faller, Keith J. Kurz, Dean L. Sicking

Department of Civil and Environmental Engineering: Faculty Publications

A crashworthy traffic noise barrier system for use alongside a path of traffic, the crashworthy traffic noise barrier system comprises a crashworthy longitudinal barrier extending substantially parallel to the path of traffic and a crashworthy traffic noise barrier wall supported by the longitudinal barrier. The crashworthy traffic noise barrier wall includes a plurality of upstanding posts attached to the traffic noise barrier wall, at least one panel supported between each adjacent pair of posts in the plurality of upstanding posts, and at least one longitudinal beam spaced above a top surface of the longitudinal barrier and extending across the plurality …


Effect Of Backwashing On Perchlorate Removal In Fixed Bed Biofilm Reactors, Young Chul Choi, Xu Li, Lutgarde Raskin, Eberhard Morgenroth Mar 2007

Effect Of Backwashing On Perchlorate Removal In Fixed Bed Biofilm Reactors, Young Chul Choi, Xu Li, Lutgarde Raskin, Eberhard Morgenroth

Department of Civil and Environmental Engineering: Faculty Publications

The influence of backwashing on biological perchlorate reduction was evaluated in two laboratory scale fixed bed biofilm reactors using 1- or 3-mm glass beads as support media. Influent perchlorate concentrations were 50 μg/L and acetate was added as the electron donor at a concentration of 2 mg C/L. Perchlorate removal was evaluated at various influent dissolved oxygen (DO) concentrations. Complete perchlorate removal was achieved with an influent DO concentration of 1 mg/L resulting in bulk phase DO concentrations below the detection limit of 0.01 mg/L. The influence of increasing influent DO concentrations for 12 h periods was evaluated before and …


Evaluation Of An Existing Steel Post Alternative For The Thrie Beam Bullnose Guardrail System, Robert W. Bielenberg, Ronald K. Faller, John R. Rohde, John D. Reid Jan 2007

Evaluation Of An Existing Steel Post Alternative For The Thrie Beam Bullnose Guardrail System, Robert W. Bielenberg, Ronald K. Faller, John R. Rohde, John D. Reid

Mid-America Transportation Center: Final Reports and Technical Briefs

Recently, the Minnesota Department of Transportation (MnDOT) funded a research project through the Midwest States Regional Pooled Fund to evaluate an existing steel post alternative for the thrie beam bullnose barrier system previously developed at the Midwest Roadside Safety Facility (MwRSF). MnDOT had an interest in the replacement of the wooden breakaway posts used in the current bullnose system with proprietary breakaway steel posts. The research project consisted of evaluation of current breakaway steel post designs, investigation and selection of a candidate post design, and full-scale testing of the bullnose system with a steel post alternative. The full-scale testing was …


Dynamic Impact Testing Of W152x13.4 (W6x9) Steel Posts On A 2:1 Slope, Gopi Dey, Ronald K. Faller, John A. Hascall, Robert W. Bielenberg, Karla A. Polivka, Kirk Molacek Jan 2007

Dynamic Impact Testing Of W152x13.4 (W6x9) Steel Posts On A 2:1 Slope, Gopi Dey, Ronald K. Faller, John A. Hascall, Robert W. Bielenberg, Karla A. Polivka, Kirk Molacek

Mid-America Transportation Center: Final Reports and Technical Briefs

Dynamic impact testing of W152x13.4 (W6x9) steel posts at various embedment depths has been detailed, and the results stated. A total of 17 bogie tests have been performed on a 2:1 slope, with post lengths varying from 1,829 mm (6 ft) through 2,743 mm (9 ft). A total of four bogie tests were performed on level terrain using 1,829-mm (6-ft) long steel posts at two different impact speeds. For each bogie test, raw acceleration data, obtained from accelerometers, was filtered and then force-displacement and energy-displacement graphs were plotted. From the energy-displacement graphs, the average post-soil forces were calculated for a …


Input-Output And Hybrid Techniques For Real-Time Prediction Of Delay And Maximum Queue Length At Signalized Intersections, Anuj Sharma, Darcy M. Bullock, James A. Bonneson Jan 2007

Input-Output And Hybrid Techniques For Real-Time Prediction Of Delay And Maximum Queue Length At Signalized Intersections, Anuj Sharma, Darcy M. Bullock, James A. Bonneson

Department of Civil and Environmental Engineering: Faculty Publications

Vehicle delay and queue length are quantitative measures of intersection performance. The technological advancement in the field of vehicle sensors and traffic controllers has reached a point where it has enabled efficient measurement of these performance measures. Two techniques are presented for real-time measurement of vehicle delay and queue length at a signalized Intersection, and these automated delay and queue estimates are compared with manually ground-truthed measurement. These techniques were evaluated at an instrumented intersection in Noblesville, Indiana. The root-mean-square error by both techniques was below 0.7 veh-s for-estimation of average delay and less than 0.15 vehicle for estimation of …


Investigating The Use Of Small-Diameter Softwood As Guardrail Posts (Dynamic Test Results), Jason A. Hascall, Ronald K. Faller, John D. Reid, Dean L. Sicking, David E. Kretschmann Jan 2007

Investigating The Use Of Small-Diameter Softwood As Guardrail Posts (Dynamic Test Results), Jason A. Hascall, Ronald K. Faller, John D. Reid, Dean L. Sicking, David E. Kretschmann

Mid-America Transportation Center: Final Reports and Technical Briefs

A modified version of the Midwest Guardrail System (MGS), utilizing small-diameter round wood posts, was developed, tested, and evaluated. Three systems were developed using different species of timber, Douglas Fir, Ponderosa Pine, and Southern Yellow Pine. A combination of Barrier VII computer simulation modeling and several series of cantilever bogie tests, conducted in both a rigid sleeve and soil, were used to determine the required diameter of post for each species in order to serve as an equivalent substitute for the standard steel post used in the barrier system. The final recommended nominal sizes were determined to be 184 mm …


Recasting Dilemma Zone Design As A Marginal Cost-Benefit Problem, Anuj Sharma, Darcy M. Bullock, Srinivas Peeta Jan 2007

Recasting Dilemma Zone Design As A Marginal Cost-Benefit Problem, Anuj Sharma, Darcy M. Bullock, Srinivas Peeta

Department of Civil and Environmental Engineering: Faculty Publications

One control objective at high-speed isolated intersections is to provide safe phase transition by minimizing the occurrence of high-speed vehicles in the dilemma zone before the phase is terminated. An upper limit for extending the green (maximum green time) is used to avoid an indefinite extension of the main-street green. Currently, the maximum green times are chosen by using engineering judgment. This approach does not explicitly consider the trade-offs between safety and delay and hence often results in both unsafe and inefficient performance at the intersection under medium to heavy traffic volumes. The dilemma problem is recast as one of …


Limitations Of Simultaneous Gap-Out Logic, Anuj Sharma, Darcy M. Bullock, Srinivas Peeta Jan 2007

Limitations Of Simultaneous Gap-Out Logic, Anuj Sharma, Darcy M. Bullock, Srinivas Peeta

Department of Civil and Environmental Engineering: Faculty Publications

The current practice of specifying simultaneous gap-out logic places constraints on signal controller logic. These constraints cannot be achieved under high traffic flow conditions, and degraded signal efficiency and dilemma zone protection often result. This study documents the phenomenon described above with set-back detectors at an instrumented intersection in Noblesville, Indiana, and characterizes the problem of dilemma zone protection as being traffic-volume dependent, a factor that should be carefully considered before the simultaneous gap-out logic is applied. Implementation of simultaneous gap-out logic led to max out ranging from 3.5% to 40% of cycles per hour during peak traffic flow periods …


Event-Based Data Collection For Generating Actuated Controller Performance Measures, Edward J. Smaglik, Anuj Sharma, Darcy M. Bullock, James R. Sturdevant, Gary Duncan Jan 2007

Event-Based Data Collection For Generating Actuated Controller Performance Measures, Edward J. Smaglik, Anuj Sharma, Darcy M. Bullock, James R. Sturdevant, Gary Duncan

Department of Civil and Environmental Engineering: Faculty Publications

Cycle-by-cycle data have been shown to be effective in the analysis of a signalized intersection with measures of effectiveness such as volume-to-capacity ratios, arrival type, and average vehicular delay. Currently, actuated traffic controllers are unable to store vehicle counts and vehicle occupancy in cycle-by-cycle bins, requiring extra equipment and personnel to collect data in these bins. The objective of this research was to develop an integrated general purpose data collection module that time stamps detector and phase state changes within a National Electrical Manufacturers Association actuated traffic signal controller and uses those data to provide quantitative graphs to assess arterial …


Self-Similarity Of Mean Flow In Pipe Turbulence, Junke Guo Jun 2006

Self-Similarity Of Mean Flow In Pipe Turbulence, Junke Guo

Department of Civil and Environmental Engineering: Faculty Publications

Based on our previous modified log-wake law in turbulent pipe ‡flows, we invent two compound similarity numbers (Y;U), where Y is a combination of the inner variable y+ and outer variable , and U is the pure exect of the wall. The two similarity numbers can well collapse mean velocity profile data with different moderate and large Reynolds numbers into a single universal profile. We then propose an arctangent law for the buffer layer and a general log law for the outer region in terms of (Y;U). From Milikan’s maximum velocity law and the Princeton superpipe data, we derive the …


Multiobjective Plan Selection Optimization For Traffic Responsive Control, Montasir M. Abbas, Anuj Sharma May 2006

Multiobjective Plan Selection Optimization For Traffic Responsive Control, Montasir M. Abbas, Anuj Sharma

Department of Civil and Environmental Engineering: Faculty Publications

Optimal coordination of traffic signals requires proper activation of timing plans to match current traffic conditions. One of the greatest challenges in configuring a traffic responsive plan selection control mode is how to select only n number of timing plans (restricted by traffic controller memory limitations) to address possibly all traffic conditions/states that can be encountered in the field, for a specific site, but most importantly, how to associate each of these traffic conditions to one of the n timing plans stored in the traffic controller. This paper uses a multiobjective non-dominated sorting genetic algorithm to (1) select the best …


Performance Evaluation Of The Midwest Guardrail System – Update To Nchrp 350 Test No. 3-11 With 28" C.G. Height (2214mg-2), Karla A. Polivka, Ronald K. Faller, Dean L. Sicking, John R. Rohde, Robert W. Bielenberg, John D. Reid Jan 2006

Performance Evaluation Of The Midwest Guardrail System – Update To Nchrp 350 Test No. 3-11 With 28" C.G. Height (2214mg-2), Karla A. Polivka, Ronald K. Faller, Dean L. Sicking, John R. Rohde, Robert W. Bielenberg, John D. Reid

Mid-America Transportation Center: Final Reports and Technical Briefs

Based on the proposed changes to the National Cooperative Highway Research Program (NCHRP) Report No. 350 guidelines, NCHRP Project 22-14(2) researchers deemed it appropriate to evaluate a strong-post W-beam guardrail systems prior to finalizing the new crash testing procedures and guidelines. For this effort, the Midwest Guardrail System (MGS) was selected for evaluation. One full-scale vehicle crash test was performed on the longitudinal barrier system in accordance with the Test Level 3 (TL-3) requirements presented in the Update to NCHRP Report No. 350. For this test, a 2270P pickup truck vehicle, which was a 1⁄2-ton, four-door vehicle with a 711 …


Performance Evaluation Of The Permanent New Jersey Safety Shape Barrier – Update To Nchrp 350 Test No. 4-12 (2214nj-2), Karla A. Polivka, Ronald K. Faller, Dean L. Sicking, John R. Rohde, Robert W. Bielenberg, John D. Reid, Brian A. Coon Jan 2006

Performance Evaluation Of The Permanent New Jersey Safety Shape Barrier – Update To Nchrp 350 Test No. 4-12 (2214nj-2), Karla A. Polivka, Ronald K. Faller, Dean L. Sicking, John R. Rohde, Robert W. Bielenberg, John D. Reid, Brian A. Coon

Mid-America Transportation Center: Final Reports and Technical Briefs

Based on the proposed changes to the National Cooperative Highway Research Program (NCHRP) Report No. 350 guidelines, NCHRP Project 22-14(2) researchers deemed it appropriate to evaluate permanent safety shape barrier systems prior to finalizing the new crash testing procedures and guidelines. For this effort, the permanent New Jersey Safety Shape barrier was selected for evaluation. One full-scale vehicle crash test was performed on the longitudinal barrier system in accordance with the Test Level 4 (TL-4) requirements presented in the Update to NCHRP Report No. 350. For the permanent barrier testing program, a 10000S single unit truck was used.

The permanent …


Muskegon Wastewater Land Treatment System: Fate And Transport Of Phosphorus In Soils And Life Expectancy Of The System, C. Hu, Tian Zhang, Y. H. Huang, Mohamed F. Dahab, D. Kendrick, R. Surampalli Jan 2006

Muskegon Wastewater Land Treatment System: Fate And Transport Of Phosphorus In Soils And Life Expectancy Of The System, C. Hu, Tian Zhang, Y. H. Huang, Mohamed F. Dahab, D. Kendrick, R. Surampalli

Department of Civil and Environmental Engineering: Faculty Publications

The build-up of phosphorus (P) in soil is a major factor limiting the operating life of a wastewater land treatment system. In this study, effects of long-term wastewater application on changes in chemical properties, P profiles, and P adsorption capacity were evaluated in soils of the Muskegon wastewater land treatment plant that has been treating wastewater for > 30 years. Results indicate that the major soil properties have been changed. In the 15 cm topsoil, the pH increased from &#;&#;5–6 in 1973 to &#;&#;7.4–7.8 in 2003; the soil’s total organic carbon (TOC) increased by 10–71 %; and the level of exchangeable …


Dissolution Kinetics Of High Explosives Particles In A Saturated Sandy Soil, Matthew C. Morley, Hiroshi Yamamoto, Gerald E. Speitel, Jr., Jay Clausen Jan 2006

Dissolution Kinetics Of High Explosives Particles In A Saturated Sandy Soil, Matthew C. Morley, Hiroshi Yamamoto, Gerald E. Speitel, Jr., Jay Clausen

Department of Civil and Environmental Engineering: Faculty Publications

Solid phase high explosive (HE) residues from munitions detonation may be a persistent source of soil and groundwater contamination at military training ranges. Saturated soil column tests were conducted to observe the dissolution behavior of individual components (RDX, HMX, and TNT) from two HE formulations (Comp B and C4). HE particles dissolved readily, with higher velocities yielding higher dissolution rates, higher mass transfer coefficients, and lower effluent concentrations. Effluent concentrations were below solubility limits for all components at superficial velocities of 10–50 cm day-1. Under continuous flow at 50 cm day-1, RDX dissolution rates from Comp …


Detection Of Inclement Weather Conditions At A Signalized Intersection Using A Video Image Processing Algorithm, Anuj Sharma, Darcy M. Bullock, Srinivas Peeta, James V. Krogmeier Jan 2006

Detection Of Inclement Weather Conditions At A Signalized Intersection Using A Video Image Processing Algorithm, Anuj Sharma, Darcy M. Bullock, Srinivas Peeta, James V. Krogmeier

Department of Civil and Environmental Engineering: Faculty Publications

Inclement weather conditions like snowfall adversely affect traffic flow characteristics, necessitating a change in parameters that define the operation of a signalized intersection. A weather-based timing plan selection is needed to maintain a desirable level of operational efficiency. Automatic implementation of weather-based timing at intersections requires accurate and timely detection of snowfall. This paper presents a snow detection algorithm that uses live video feed obtained from a video image vehicle detection system present at an intersection.


Stochastic Algorithm For Improved Operations At Isolated High Speed Intersections, Anuj Sharma, Darcy M. Bullock, Srinivas Peeta Jan 2006

Stochastic Algorithm For Improved Operations At Isolated High Speed Intersections, Anuj Sharma, Darcy M. Bullock, Srinivas Peeta

Department of Civil and Environmental Engineering: Faculty Publications

The current practice of specifying simultaneous gap out logic at isolated high speed signalized intersections places constraints on the signal controller logic that cannot be satisfied under high congestion level. Further, it often results in degraded signal efficiency and dilemma zone protection. A stochastic approach is proposed in this paper with the objective of increasing safety and efficiency at these intersections.


Least-Squares Finite-Element Scheme For The Lattice Boltzmann Method On An Unstructured Mesh, Yusong Li, Eugene J. Leboeuf, P. K. Basu Oct 2005

Least-Squares Finite-Element Scheme For The Lattice Boltzmann Method On An Unstructured Mesh, Yusong Li, Eugene J. Leboeuf, P. K. Basu

Department of Civil and Environmental Engineering: Faculty Publications

A numerical model of the lattice Boltzmann method (LBM) utilizing least-squares finite-element method in space and the Crank–Nicolson method in time is developed. This method is able to solve fluid flow in domains that contain complex or irregular geometric boundaries by using the flexibility and numerical stability of a finite-element method, while employing accurate least-squares optimization. Fourth-order accuracy in space and second-order accuracy in time are derived for a pure advection equation on a uniform mesh; while high stability is implied from a von Neumann linearized stability analysis. Implemented on unstructured mesh through an innovative element-by-element approach, the proposed method …


Modified Log–Wake Law For Zero-Pressure-Gradient Turbulent Boundary Layers, Junke Guo, Pierre Y. Julien, Meroney N. Meroney Sep 2005

Modified Log–Wake Law For Zero-Pressure-Gradient Turbulent Boundary Layers, Junke Guo, Pierre Y. Julien, Meroney N. Meroney

Department of Civil and Environmental Engineering: Faculty Publications

This paper shows that the turbulent velocity profile for zero-pressure-gradient boundary layers is affected by the wall shear stress and convective inertia. The effect of the wall shear stress is dominant in the so-called overlap region and can be described by a logarithmic law in which the von Karman constant is about 0.4 while the additive constant depends on a Reynolds number. The effect of the convective inertia can be described by the Coles wake law with a constant wake strength about 0.76.A cubic correction term is introduced to satisfy the zero velocity gradient requirement at the boundary layer edge. …


Effects Of Long-Term Wastewater Application On Chemical Properties And Phosphorus Adsorption Capacity In Soils Of A Wastewater Land Treatment System, Cong Hu, Tian Zhang, Yong Huang, Mohamed F. Dahab, Rao Surampalli Aug 2005

Effects Of Long-Term Wastewater Application On Chemical Properties And Phosphorus Adsorption Capacity In Soils Of A Wastewater Land Treatment System, Cong Hu, Tian Zhang, Yong Huang, Mohamed F. Dahab, Rao Surampalli

Department of Civil and Environmental Engineering: Faculty Publications

The buildup of phosphorus (P) in the soil is a major factor limiting the operating life of a wastewater land treatment system. In this study, we evaluated changes of chemical properties, P profiles, and adsorption isotherms in the soils of a Muskegon wastewater land treatment system, which has received wastewater for ~30 years. It was found that the pH in the 15-cm topsoil increased from ~5-6 in 1973 to ~7.4-7.8 in 2003; a large amount of salt (e.g., Ca, Mg) in wastewater was adsorbed by the soil; the soil Al content (either exchangeable or oxalate extractable) decreased, while the oxalate-extractable …


High-Impact, Energy-Absorbing Vehicle Barrier System: U.S. Patent No. Us 6,926,461 B1, Ronald K. Faller, Dean L. Sicking, John R. Rohde, A. Keller, Robert W. Bielenberg, James C. Holloway, Kenneth H. Addink, Karla A. Polivka Aug 2005

High-Impact, Energy-Absorbing Vehicle Barrier System: U.S. Patent No. Us 6,926,461 B1, Ronald K. Faller, Dean L. Sicking, John R. Rohde, A. Keller, Robert W. Bielenberg, James C. Holloway, Kenneth H. Addink, Karla A. Polivka

Department of Civil and Environmental Engineering: Faculty Publications

A high-impact, energy-absorbing vehicle barrier system generally includes a substantially rigid outer containment wall coupled via cable restraint assemblies with an energy-absorbing inner impact wall, and energy-absorbing cartridges strategically positioned between the impact wall and containment-wall: The impact wall is constructed of a number of rectangular tubes coupled with one another to presents a substantially smooth, uniform surface to passing vehicles. The energy-absorbing cartridges generally consist of a number of foam sheets which compress and crush between the containment wall and impact wall to absorb energy from an errant vehicle striking the face of the impact wall, while the deflection …


Stochastic Modeling Of The Permeability Of Randomly Generated Porous Media, Yusong Li, Eugene Leboeuf, P. K. Basu, Sankaran Mahadevan Aug 2005

Stochastic Modeling Of The Permeability Of Randomly Generated Porous Media, Yusong Li, Eugene Leboeuf, P. K. Basu, Sankaran Mahadevan

Department of Civil and Environmental Engineering: Faculty Publications

Permeability of porous media in subsurface environments is subject to potentially large uncertainties due to the heterogeneity of natural systems. In this study, a first-order reliability method (FORM) is combined with a lattice Boltzmann method (LBM) to estimate the permeability of randomly generated porous media. The proposed procedure provides an increased ease of addressing complex pore structures by employing LBM to model fluid flow, while inheriting the computational efficiency from FORM. Macroscale- equivalent permeability can thus be estimated with significantly reduced computational efforts, while maintaining a connection to the complex microscale fluid dynamics within a pore structure environment. Implemented on …


Composite Action System And Method: U.S. Patent No. Us 6,871,462 B2, Atorod Azizinamini Mar 2005

Composite Action System And Method: U.S. Patent No. Us 6,871,462 B2, Atorod Azizinamini

Department of Civil and Environmental Engineering: Faculty Publications

The present invention provides a composite action system and a method for fabricating the same to meet OSHA safety requirements and allow for welding off the work site. An improved structural system achieves the desired composite behavior by providing one or more structural members, plates coupled with the structural members, transverse reinforcing members passing through apertures in the plates, and additional reinforcing members positioned parallel and transverse to the structural members to provide an interlocking composite action between the structural members, reinforcing members, and concrete.


Shear Stress In Smooth Rectangular Open-Channel Flows, Junke Guo, Pierre Y. Julien Jan 2005

Shear Stress In Smooth Rectangular Open-Channel Flows, Junke Guo, Pierre Y. Julien

Department of Civil and Environmental Engineering: Faculty Publications

The average bed and sidewall shear stresses in smooth rectangular open-channel flows are determined after solving the continuity and momentum equations. The analysis shows that the shear stresses are function of three components: (1) gravitational; (2) secondary flows; and (3) interfacial shear stress. An analytical solution in terms of series expansion is obtained for the case of constant eddy viscosity without secondary currents. In comparison with laboratory measurements, it slightly overestimates the average bed shear stress measurements but underestimates the average sidewall shear stress by 17% when the width–depth ratio becomes large. A second approximation is formulated after introducing two …


Configuration Methodology For Traffic-Responsive Plan Selection: A Global Perspective, Montasir M. Abbas, Nadeem A. Chaudhary, Geza Pesti, Anuj Sharma Jan 2005

Configuration Methodology For Traffic-Responsive Plan Selection: A Global Perspective, Montasir M. Abbas, Nadeem A. Chaudhary, Geza Pesti, Anuj Sharma

Department of Civil and Environmental Engineering: Faculty Publications

Although several studies have shown the potential great benefits of traffic-responsive plan selection (TRPS) control, time-of-day operation continues to be the primary method used to select patterns for signal control applications. This practice could be largely attributed to the minimal guidelines available on the setup of the TRPS mode. An innovative framework for TRPS system setup is provided, and guidelines for implementing TRPS in a simplified manner are shown. The guidelines, developed at Texas Transportation Institute (TTI), use a comprehensive approach that incorporates a multiobjective evolutionary algorithm and a supervised discriminant analysis. Engineers can directly implement the guidelines presented as …


Optimization Of Time Of Day Plan Scheduling Using A Multi-Objective Evolutionary Algorithm, Montasir M. Abbas, Anuj Sharma Jan 2005

Optimization Of Time Of Day Plan Scheduling Using A Multi-Objective Evolutionary Algorithm, Montasir M. Abbas, Anuj Sharma

Department of Civil and Environmental Engineering: Faculty Publications

Coordinating traffic signals can provide great savings to motorists in terms of reduced delays and number of vehicular stops. In order to maximize benefits, engineers need to use a mechanism by which the most optimal timing plans are activated when the traffic patterns change. Common ways of accomplishing this need is by using Time of Day (TOD) plan scheduling, or Traffic Responsive Plan Selection (TRPS). Out of the two modes, the TOD mode is by far the most common. Engineers, however, typically use their judgment to determine the TOD plan scheduling. Unless traffic patterns change at certain times of the …


Efficient Algorithm For Computing Einstein Integrals, Junke Guo, Pierre Y. Julien Dec 2004

Efficient Algorithm For Computing Einstein Integrals, Junke Guo, Pierre Y. Julien

Department of Civil and Environmental Engineering: Faculty Publications

Analytical approximations to Einstein integrals are proposed. The approximations represented by two fast-converging series are valid for all values of their arguments. Accordingly, the algorithm can be easily incorporated into professional software like HEC-RAS or HEC-6 with minimum computational effort.


Determination Of Traffic Responsive Plan Selection Factors And Thresholds Using Artificial Neural Networks, Anuj Sharma Aug 2004

Determination Of Traffic Responsive Plan Selection Factors And Thresholds Using Artificial Neural Networks, Anuj Sharma

Department of Civil and Environmental Engineering: Faculty Publications

Traffic congestion has become a menace to civilized society. It degrades air quality, jeopardizes safety and causes delay. Traffic congestion can be alleviated by providing an effective traffic control signal system. Closed-loop traffic control systems are an example of such a system.

Closed-loop traffic control systems can be operated primarily in either of two modes: Time of Day Mode (TOD) or Traffic Responsive Plan Selection Mode (TRPS). TRPS mode, if properly configured, can easily handle time independent variation in traffic volumes. It can also reduce the effect of timing plan aging. Despite these advantages, TRPS mode is not used as …


Least-Squares Finite-Element Lattice Boltzmann Method, Yusong Li, Eugene J. Leboeuf, P. K. Basu Jun 2004

Least-Squares Finite-Element Lattice Boltzmann Method, Yusong Li, Eugene J. Leboeuf, P. K. Basu

Department of Civil and Environmental Engineering: Faculty Publications

A new numerical model of the lattice Boltzmann method utilizing least-squares finite element in space and Crank-Nicolson method in time is presented. The new method is able to solve problem domains that contain complex or irregular geometric boundaries by using finite-element method’s geometric flexibility and numerical stability, while employing efficient and accurate least-squares optimization. For the pure advection equation on a uniform mesh, the proposed method provides for fourth-order accuracy in space and second-order accuracy in time, with unconditional stability in the time domain. Accurate numerical results are presented through two-dimensional incompressible Poiseuille flow and Couette flow.