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Articles 1 - 15 of 15
Full-Text Articles in Engineering
Using Archived Its Data To Measure The Operational Benefits Of A System-Wide Adaptive Ramp Metering System, Robert L. Bertini, Christopher Monsere, Oren Eshel, Soyoung Ahn
Using Archived Its Data To Measure The Operational Benefits Of A System-Wide Adaptive Ramp Metering System, Robert L. Bertini, Christopher Monsere, Oren Eshel, Soyoung Ahn
Civil and Environmental Engineering Faculty Publications and Presentations
A System-Wide Adaptive Ramp Metering (SWARM) system has been implemented in the Portland, Oregon metropolitan area, replacing the previous pre-timed ramp-metering system that had been in operation since 1981. SWARM has been deployed on six major corridors and operates during the morning and afternoon peak hours. This report presents results of a "before" and "after" evaluation of the performance of two freeway corridors as part of ongoing efforts to measure the benefits of the new SWARM system, as compared to the pre-timed system. The study benefited from using the existing regional data, surveillance and communications infrastructure in addition to a …
A Method For Processing Acoustic Doppler Current Profiler Velocity Data From Towed, Undulating Vehicles, David A. Jay, Jiayi Pan
A Method For Processing Acoustic Doppler Current Profiler Velocity Data From Towed, Undulating Vehicles, David A. Jay, Jiayi Pan
Civil and Environmental Engineering Faculty Publications and Presentations
The utility of the acoustic Doppler current profiler (ADCP) for sampling small time and space scales of coastal environments can be enhanced by mounting a high-frequency (1200 kHz) ADCP on an oscillating towed body. This approach requires both an external reference to convert the measured shears to velocities in the earth coordinates and a method to determine the towed body velocities. During the River Influence on the Shelf Ecosystems (RISE) project cruise, a high-frequency (1200 kHz) and narrowbeam ADCP with mode 12 sampling was mounted on a TRIAXUS oscillating towfish, which steers a 3D path behind the ship. This deployment …
The Inverse Ocean Modeling System. Part Ii: Applications, J. C. Muccino, H. G. Arango, Andrew F. Bennett, B. S. Chua, Julia Muccino Cornuelle, E. Di Lorenzo, Gary D. Egbert, D. Haidvogel, J. C. Levin, H. Luo, A. J. Miller, A. M. Moore, Edward D. Zaron
The Inverse Ocean Modeling System. Part Ii: Applications, J. C. Muccino, H. G. Arango, Andrew F. Bennett, B. S. Chua, Julia Muccino Cornuelle, E. Di Lorenzo, Gary D. Egbert, D. Haidvogel, J. C. Levin, H. Luo, A. J. Miller, A. M. Moore, Edward D. Zaron
Civil and Environmental Engineering Faculty Publications and Presentations
The Inverse Ocean Modeling (IOM) System is a modular system for constructing and running weak-constraint four-dimensional variational data assimilation (W4DVAR) for any linear or nonlinear functionally smooth dynamical model and observing array. The IOM has been applied to four ocean models with widely varying characteristics. The Primitive Equations Z-coordinate-Harmonic Analysis of Tides (PEZ-HAT) and the Regional Ocean Modeling System (ROMS) are three-dimensional, primitive equations models while the Advanced Circulation model in 2D (ADCIRC-2D) and Spectral Element Ocean Model in 2D (SEOM-2D) are shallow-water models belonging to the general finite-element family. These models, in conjunction with the IOM, have been used …
Effects Of Ambient Velocity Shear On Nonlinear Internal Wave Associated Mixing At The Columbia River Plume Front, Jiayi Pan, David A. Jay
Effects Of Ambient Velocity Shear On Nonlinear Internal Wave Associated Mixing At The Columbia River Plume Front, Jiayi Pan, David A. Jay
Civil and Environmental Engineering Faculty Publications and Presentations
Large-amplitude nonlinear internal waves (NLIWs) are frequently observed propagating away from Columbia River tidal plume fronts. They are generated because of the deceleration of the frontal bulge. During the River Influences on Shelf Ecosystems project cruises, the velocity, density structure and acoustic backscatter of the plume fronts and frontal NLIWs were observed using a towed vehicle, vessel-mounted instrumentation, and a vessel X band radar. These observations indicate that in the presence of strong ambient velocity shear, the NLIWs with maximum amplitudes occur well below the density interface and at a depth deeper than in the absence of shear. This deepening …
2007 Portland Metropolitan Region Transportation System Performance Report, Robert Bertini
2007 Portland Metropolitan Region Transportation System Performance Report, Robert Bertini
Civil and Environmental Engineering Faculty Publications and Presentations
Our transportation system is a key ingredient in the economy, quality of life and urban fabric of the Portland metropolitan area. It has been stated in the past that it is not possible to manage our transportation system tomorrow unless we understand how it is performing today. In this spirit, the Portland State University Center for Transportation Studies has been working with regional and statewide partners to develop new capabilities to measure, monitor and track the performance of the transportation system in real time and using archived data sources. We believe that it is possible to leverage these disparate data …
An Iterative Route Construction And Improvement Algorithm For The Vehicle Routing Problem With Soft And Hard Time Windows, Miguel A. Figliozzi
An Iterative Route Construction And Improvement Algorithm For The Vehicle Routing Problem With Soft And Hard Time Windows, Miguel A. Figliozzi
Civil and Environmental Engineering Faculty Publications and Presentations
The joint solution of routing problems with soft and hard time windows has valuable practical applications. Simultaneous solution approaches to both types of problems are needed when: (a) the number of routes needed for hard time windows exceeds the number of available vehicles, (b) a study of cost-service tradeoffs is required or the dispatcher has qualitative information regarding the relative importance of hard time window constraints across customers. A new Iterative Route Construction and Improvement (IRCI) algorithm of average run time performance O(n2 ) is proposed to sequentially solve Vehicle Routing Problems with Soft Time Windows (VRPSTW) and Hard Time …
Hydrologic Remote Sensing And Land Surface Data Assimilation, Hamid Moradkhani
Hydrologic Remote Sensing And Land Surface Data Assimilation, Hamid Moradkhani
Civil and Environmental Engineering Faculty Publications and Presentations
Accurate, reliable and skillful forecasting of key environmental variables such as soil moisture and snow are of paramount importance due to their strong influence on many water resources applications including flood control, agricultural production and effective water resources management which collectively control the behavior of the climate system. Soil moisture is a key state variable in land surface?atmosphere interactions affecting surface energy fluxes, runoff and the radiation balance. Snow processes also have a large influence on land-atmosphere energy exchanges due to snow high albedo, low thermal conductivity and considerable spatial and temporal variability resulting in the dramatic change on surface …
A Strategy For Reducing The Impact Of Driving Under Influence Of Intoxicants In Portland, Oregon, Christopher Monsere, Delia Chi
A Strategy For Reducing The Impact Of Driving Under Influence Of Intoxicants In Portland, Oregon, Christopher Monsere, Delia Chi
Civil and Environmental Engineering Faculty Publications and Presentations
Driving under the influence of intoxicants (DUII) applies to operating a vehicle under the influence of any substance that can impair driving performance. Nationally and locally there is a strong desire to reduce the societal impacts of this significant social problem. The trend in U.S. alcohol-related motor vehicle crashes was generally decreasing in the mid to late 1980’s but has remained fairly flat since the early 1990s. In 1982, approximately 60% of all US traffic fatalities were alcohol-related. By 1994, this had decreased to 43% but in the decade that followed it has changed little. In 2005, nearly 39% of …
Daily Forecasts Of Columbia River Plume Circulation: A Tale Of Spring/Summer Cruises, Yinglong J. Zhang, Antonio M. Baptista, Barbara M. Hickey, Byron C. Crump, David A. Jay, Michael Wilkin, Charles Seaton
Daily Forecasts Of Columbia River Plume Circulation: A Tale Of Spring/Summer Cruises, Yinglong J. Zhang, Antonio M. Baptista, Barbara M. Hickey, Byron C. Crump, David A. Jay, Michael Wilkin, Charles Seaton
Civil and Environmental Engineering Faculty Publications and Presentations
Semi-operational daily forecasts of circulation from an observatory for the Columbia River estuary-plume-shelf system routinely support oceanographic cruises, by providing 24h-ahead estimates of plume location and structure for planning purposes and for near real-time interpretation of observations. This paper analyzes forecast skill during spring/summer cruises in 2004-2007. Assessment addresses both qualitative descriptions of major plume trends and features and quantitative representation of data from (primarily) vessel-based flow-through, cast and towed systems. Forecasts emerge as robust predictors of plume location and variability, with skill that has grown over time, at least in part due to improvements in model algorithms. When the …
Seasonal Variability And Estuary-Shelf Interactions In Circulation Dynamics Of A River-Dominated Estuary, Arun Chawla, David A. Jay, Antonio M. Baptista, Michael Wilkin, Charles Seaton
Seasonal Variability And Estuary-Shelf Interactions In Circulation Dynamics Of A River-Dominated Estuary, Arun Chawla, David A. Jay, Antonio M. Baptista, Michael Wilkin, Charles Seaton
Civil and Environmental Engineering Faculty Publications and Presentations
The long-term response of circulation processes to external forcing has been quantified for the Columbia River estuary using in situ data from an existing coastal observatory. Circulation patterns were determined from four Acoustic Doppler Profilers (ADP) and several conductivity-temperature sensors placed in the two main channels. Because of the very strong river discharge, baroclinic processes play a crucial role in the circulation dynamics, and the interaction of the tidal and subtidal baroclinic pressure gradients plays a major role in structuring the velocity field. The input of river flow and the resulting low-frequency flow dynamics in the two channels are quite …
Suspended Sediment Fluxes At An Intertidal Flat: The Shifting Influence Of Wave, Wind, Tidal, And Freshwater Forcing, Stefan A. Talke, Mark T. Stacey
Suspended Sediment Fluxes At An Intertidal Flat: The Shifting Influence Of Wave, Wind, Tidal, And Freshwater Forcing, Stefan A. Talke, Mark T. Stacey
Civil and Environmental Engineering Faculty Publications and Presentations
Using in situ, continuous, high frequency (8–16 Hz) measurements of velocity, suspended sediment concentration (SSC), and salinity, we investigate the factors affecting near-bed sediment flux during and after a meteorological event (cold front) on an intertidal flat in central San Francisco Bay. Hydrodynamic forcing occurs over many frequency bands including wind wave, ocean swell, seiching (500–1000 s), tidal, and infra-tidal frequencies, and varies greatly over the time scale of hours and days. Sediment fluxes occur primarily due to variations in flow and SSC at three different scales: residual (tidally averaged), tidal, and seiching. During the meteorological event, sediment fluxes are …
New Insights Into The Controls And Mechanisms Of Plankton Productivity Along The Us West Coast, Raphael M. Kudela, Neil S. Banas, John A. Barth, Elizabeth R. Frame, David A. Jay, John L. Largier, Evelyn J. Lessard, Tawnya D. Peterson, Andrea J. Vander Woude
New Insights Into The Controls And Mechanisms Of Plankton Productivity Along The Us West Coast, Raphael M. Kudela, Neil S. Banas, John A. Barth, Elizabeth R. Frame, David A. Jay, John L. Largier, Evelyn J. Lessard, Tawnya D. Peterson, Andrea J. Vander Woude
Civil and Environmental Engineering Faculty Publications and Presentations
During the lifetime of the National Science Foundation's Coastal Ocean Processes program, four experiments were conducted on the US West Coast in the northern California Current System. Although each project had a unique scientific focus, all four addressed the mechanisms causing eastern boundary current systems in general, and the California Current System in particular, to be biologically rich, from phytoplankton to apex predators. Taken together, findings from these projects provide new insights into the canonical view that upwelling systems are simple wind-driven "conveyor belts," bringing cold, nutrient-rich waters to the well-lit surface ocean where biological organisms flourish. We highlight new …
Optimal Bus Stop Spacing For Minimizing Transit Operation Cost, Huan Li, Robert L. Bertini
Optimal Bus Stop Spacing For Minimizing Transit Operation Cost, Huan Li, Robert L. Bertini
Civil and Environmental Engineering Faculty Publications and Presentations
With the increasing attention to finance issues relative to transit operation, a bus stop spacing model is generated with the aim at minimizing the operation cost without impact on transit accessibility. Two cost functions are considered in the model including passenger access cost and in-vehicle passenger stopping cost aiming at minimizing total cost. A bus route in Portland, Oregon, USA is examined as an example using Archived Bus Dispatch System (BDS) data provided by TriMet, the regional transit provider for the Portland, Oregon metropolitan area. Based on the optimization model, the theoretical optimized bus stop spacing is 930 feet comparing …
Combining Climate, Crash, And Highway Data For Improved Ranking Of Speed And Winter-Weather Related Crash Locations In Oregon, Christopher M. Monsere, Peter G. Bosa, Robert L. Bertini
Combining Climate, Crash, And Highway Data For Improved Ranking Of Speed And Winter-Weather Related Crash Locations In Oregon, Christopher M. Monsere, Peter G. Bosa, Robert L. Bertini
Civil and Environmental Engineering Faculty Publications and Presentations
In recent years, the techniques for screening transportation networks to identify high crash locations have become more sophisticated. Many transportation agencies, however, lack sufficient data, either in timeliness, completeness, or accuracy to implement many of the recent advances. This paper presents the results of an empirical analysis of screening and ranking for specific crash type (speed and ice related crashes) on rural 1.6 km (1 mi) highway sections of Oregon highways. The analysis includes data generated with the extensive use of spatial techniques and incorporates climate data to enhance environmental considerations. The paper compares the results of five ranking methods—critical …
New Particle Formation In The Front Range Of The Colorado Rocky Mountains, Micahel Boy, Thomas Karl, Andrew Turnipseed, Roy Lee Mauldin, Edward Kosciuch, James Greenberg, Jeff Rathbone, James Smith, Andreas Held, Kelley Barsanti, Alex Guenther
New Particle Formation In The Front Range Of The Colorado Rocky Mountains, Micahel Boy, Thomas Karl, Andrew Turnipseed, Roy Lee Mauldin, Edward Kosciuch, James Greenberg, Jeff Rathbone, James Smith, Andreas Held, Kelley Barsanti, Alex Guenther
Civil and Environmental Engineering Faculty Publications and Presentations
New particle formation is of interest because of its influence on the properties of aerosol population, and due to the possible contribution of newly formed particles to cloud condensation nuclei. Currently no conclusive evidence exists as to the mechanism or mechanisms of nucleation and subsequent particle growth. However, nucleation rates exhibit a clear dependence on ambient sulphuric acid concentrations and particle growth is often attributed to the condensation of organic vapours. A detailed study of new particle formation in the Front Range of the Colorado Rocky Mountains is presented here. Gas and particle measurement data for 32 days was analyzed …