1,146 research outputs found
Festival on Fifth Street: A Multi-modal Streetscape and Cultural Center in Downtown Bismarck, North Dakota.
This thesis is a study conducted to explore the effects of revitalizing a downtown street emphasizing the pedestrian. Through research, the streetscape will be redeveloped for the safety of pedestrians as well as various modes of traffic. Discovering what activities the pedestrian wants on a street will bring a steady flow of people to utilize a downtown space more often and make the street more comfortable to be shared with pedestrians as well as modes of transportation. The study considers adding the elements of a complete street (drive, bike, parking, transit, and walk lanes, also, planting and furniture zones) street trees/shrubs and new paving patterns to the urban core and community space for both private and civic use. As defined from the research and along with case studies the final design of a better streetscape for pedestrians will be accomplished
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Supervised gamma process Poisson factorization
textThis thesis develops the supervised gamma process Poisson factorization (S-GPPF) framework, a novel supervised topic model for joint modeling of count matrices and document labels. S-GPPF is fully generative and nonparametric: document labels and count matrices are modeled under a unified probabilistic framework and the number of latent topics is controlled automatically via a gamma process prior. The framework provides for multi-class classification of documents using a generative max-margin classifier. Several recent data augmentation techniques are leveraged to provide for exact inference using a Gibbs sampling scheme. The first portion of this thesis reviews supervised topic modeling and several key mathematical devices used in the formulation of S-GPPF. The thesis then introduces the S-GPPF generative model and derives the conditional posterior distributions of the latent variables for posterior inference via Gibbs sampling. The S-GPPF is shown to exhibit state-of-the-art performance for joint topic modeling and document classification on a dataset of conference abstracts, beating out competing supervised topic models. The unique properties of S-GPPF along with its competitive performance make it a novel contribution to supervised topic modeling.Electrical and Computer Engineerin
Internationalization within networks: Exploring the relationship between inward and outward FDI in China’s auto components industry
This is the author accepted manuscript. The final version is available from Springer via https://doi.org/
10.1007/s10490-015-9422-3We explore how the outward FDI strategies of Chinese auto component MNCs are
shaped by sub-contracting supply relationships established with developed market MNCs.
We argue the strong presence of foreign MNC business networks developed through prior
inward FDI constitutes an important home country effect influencing the outward FDI
strategies of emerging market MNCs. Using the updated internationalization process model,
we show how commitment to business networks is a critical mechanism driving the
internationalization trajectories of Chinese auto component MNCs. This includes geographic
location choices to psychically distant developed markets, strategic asset seeking orientation,
pace of internationalisation and entry mode decisions
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Using Outlier Analysis for the Detection of Propagandists in Epistemic Networks
There have been many discussions in recent years about the implications that Disinformation has on freedom of speech. I offer a framework by how we may be able to remove certain pieces of Disinformation from parts of the internet while not violating the first amendment.</p
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Improving Safety of the Platform-Train-Interface Through Operational and Technical Mitigation Strategies
The purpose of this study is to provide background information and examples of best practices relating to platform-train-interface (PTI) safety. The research and information obtained for this manuscript has been in association with the A-40 project funded by the Transit Cooperative Research Program (TCRP) of the National Academies. The purpose of the TCRP A-40 project is to create a manual to improve platform safety for rail modes of public transportation at the interface between the edge of the platform and the vehicle. Information has been collected via an extensive literature review, phone interviews with stakeholders, basic incident data analysis, and site visits. Research has determined that the three main factors that affect platform safety are technical aspects, operational elements, and passenger characteristics. The focus of this document is to better understand the issues and potential mitigation strategies associated with the operational and technical aspects of platform-train-interface safety
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Recommendations for Implementing Hepatitis C Virus Care in Homeless Shelters: The Stakeholder Perspective.
Compared with the general population, homeless individuals are at higher risk of hepatitis C infection (HCV) and may face unique barriers in receipt of HCV care. This study sought the perspectives of key stakeholders toward establishing a universal HCV screening, testing, and treatment protocol for individuals accessing homeless shelters. Four focus groups were conducted with homeless shelter staff, practice providers, and social service outreach workers (n = 27) in San Francisco, California, and Minneapolis, Minnesota. Focus groups evaluated key societal, system, and individual-level facilitators and barriers to HCV testing and management. Interviews were transcribed and analyzed thematically. The societal-level barriers identified were lack of insurance, high-out-of-pocket expenses, restriction of access to HCV treatment due to active drug and/or alcohol use, and excessive paperwork required for HCV treatment authorization from payers. System-level barriers included workforce constraints and limited health care infrastructure, HCV stigma, low knowledge of HCV treatment, and existing shelter policies. At the individual level, client barriers included competing priorities, behavioral health concerns, and health attitudes. Facilitators at the system level for HCV care service integration in the shelter setting included high acceptability and buy in, and linkage with social service providers. Conclusion: Despite societal, system, and individual-level barriers identified with respect to the scale-up of HCV services in homeless shelters, there was broad support from key stakeholders for increasing capacity for the provision of HCV services in shelter settings. Recommendations for the scale-up of HCV services in homeless shelter settings are discussed
Laboratory freeze-thaw durability of pervious concrete with respect to curing time and addition of sand, slag, silica fume, and saltguard
Concerns persist regarding pervious concrete durability in cold climates related to freeze-thaw and exposure to salt. This study was conducted as an extension to previous work regarding pervious concrete in Vermont, to further investigate freeze-thaw durability with salt exposure in a laboratory environment representative of field conditions. Pervious concrete specimen variations included the addition of sand, replacement of cement with slag, replacement of cement with slag with silica fume, curing time, and saltguard treatment. The addition of 5% sand improved freeze-thaw durability, while the addition of 10% sand led to decreased workability, density, and durability. Both the slag and slag with silica fume cement replacements improved the freeze-thaw durability in comparison to the cement only base mix. Curing time (7 to 56 days) did not influence freeze-thaw durability of pervious concrete with slag or slag with silica fume replacement. The application of liquid saltguard treatment for freeze-thaw resistance was found to be best performed using a dipping procedure over spraying the surface of the pervious concrete. Considering the results of the current work as well as previous work regarding pervious concrete conducted at the University of Vermont and Norwich University, the following general conclusions are drawn which may assist in future pervious concrete mix designs and treatments. In general, the presence of sand replacing a small portion of coarse aggregate (up to about 10%) seems to improve freeze-thaw durability of pervious concrete. Adding sand to a mix design without making adjustments to water-tocement ratio and other ingredients will most likely be not beneficial, as adding sand makes the cement ratio lower, resulting in decreased workability, and lower densities. Replacing up to 20% of Portland cement with slag or slag with silica fume also appears to have benefits in improving freeze thaw durability of pervious concrete. Use of slag or slag with silica fume seem to yield better durability than using fly ash as cement replacement. It is likely that incorporating both sand replacement and cementitious alternatives (slag and slag with silica fume) may represent a more durable pervious concrete mix. If precast pervious concrete slabs were to be used, longer curing times and coating the slabs with saltguard may prove to be beneficial; however, any environmental concerns associated with the latter need to be investigated in future studies
A hybrid approach to beach erosion mitigation and amenity enhancement, St Francis Bay, South Africa
The St Francis Bay beach has experienced chronic erosion over the past three decades. This erosion can largely be attributed to the stabilisation of a large coastal dunefield which contributed +/- 80 percent of the sand supply to St Francis Bay. Stabilisation began in 1975 initially using plant cuttings and followed by the development of the Santareme holiday suburb resulting in complete stabilisation by 1985. Effects were felt from the late 1970‟s and since then the beach has retreated at between 0.5 - 3 m.yr-1. Erosion has encroached on beachfront properties since the early 1990‟s, leading to the placement of 3-4 m high unsightly rock revetments along much of the beach. Where properly maintained these structures have proved successful in protecting the properties behind, however exacerbated erosion of areas in front and adjacent to these structures is evident. Currently no dry beach is present at high tide for most of the year, leading to a significant reduction in beach amenity value. Several technical studies to investigate remediation of this beach erosion problem have been conducted since the early 1990‟s. This study includes investigations into the processes and dynamics of the existing environment and evaluation of the effectiveness and impacts of several elements of a hybrid approach to coastal protection and amenity enhancement for St Francis Bay beach. This proposal incorporated: Multi-Purpose Reefs (MPR‟s) offshore, for coastal protection and amenity enhancement in terms of surfing; beach nourishment with sand from the Kromme Estuary and dune rehabilitation with appropriate native sand binding species. Extensive fieldwork and data collection were conducted, this included: a series of bathymetric surveys; diving surveys and a helicopter flight; sediment sampling; beach profiling and deployment of a wave/current meter. Analysis of these data provided a greater understanding of the existing environment and dynamics of St Francis Bay and provided reliable inputs for numerical modelling. Numerical and physical modelling was conducted to assess the existing processes and conduct MPR design testing. In addition calibrated hydrodynamic modelling of the Kromme Estuary was conducted in order to assess the impacts of sand extraction from the large sand banks within the mouth of the Kromme Estuary for use as beach nourishment. Comparison of bathymetric survey data collected by the author in 2005/06 with survey data collected by the South African Navy Hydrographic Office (SANHO) in 1952 suggest a major loss of sand from the bay, with a volume difference of some 8.8 X 106 m3 calculated. Greater losses were measured between 10-15 m water depths, with shallow areas of +/- 5 m water depth, remaining more stable. This can be attributed to the presence of shallow reef and rocky substrate through much of the bay at this depth range. Monthly RTK GPS survey data from September 2006 to September 2007 indicates a total loss of 40 000 m3 over this period with the greatest losses measured along the northern part of the beach. The greatest losses were measured after large long period waves from a southerly to south-easterly direction occurred in conjunction with equinox tides in mid March 2007. Sediment sampling at over 100 locations within the bay indicated a high percentage of reef (26 percent) and fairly consistent grain size in the fine to medium size class throughout much of the beach, bay and large sand bank within the estuary. While the majority of the South African Coast is exposed to the predominant south westerly winds and waves, St Francis Bay‟s orientation means that waves from a south easterly to easterly direction dominate. The results of the detailed numerical modelling of the hydrodynamics agree with previous calculations and modelling results which concluded that strong unidirectional longshore currents occur along the headland due to the oblique angle of wave incidence and the close to parallel angle of wave incidence along the beach leads to weak longshore currents of variable direction. Erosion along St Francis Bay beach is a result of cross-shore erosion due to large waves from a southerly to easterly direction. Detached breakwaters are the most effective form of coastal protection in these environments and MPR‟s offer additional benefits over traditional breakwater structures. Results of empirical calculations and numerical modelling indicate that the MPR‟s will provide effective coastal protection through the processes of wave dissipation, wave rotation, salient formation and alteration of nearshore circulation. Physical modelling results allowed the MPR design to be assessed and refined in terms of surfing amenity enhancement and construction constraints. In addition numerical modelling results indicate that impacts due to the extraction of up to 600 000 m3 of sand from the lower Kromme Estuary result in highly localised velocity reduction, mainly limited to the extraction areas. The calculated rate of sediment influx into the lower Kromme Estuary indicates that limited extraction, in the order of 20 000 – 40 000 m3 per year, should be sustainable in the long term. Sedimentation of the lower estuary over recent years has had negative recreational and ecological impacts, through reduced navigability and water exchange respectively. Therefore both the estuary and beach systems prove to benefit from this approach. Although not investigated in detail as part of this study, evidence from numerous projects worldwide indicates that foredunes help to trap wind-blown sand on the beach and form a buffer to storm erosion, therefore dune rehabilitation with native sand-binding plant species was recommended as the third element of the proposed remediation of St Francis Bay beach
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The Art of Reducing Coastal Hazard Complexity: Coupling Physics and Probability to Understand Extremes, Variability, and Climate-dependence
Coastal hazards are the result of numerous physical processes cumulatively causing water levels to flood and erode the land. The waves, storm surges, tides, and run-off contributing to elevated water levels are each the product of chaotic and random weather patterns. These stochastic weather patterns dissipate energy in Earth's climate system. The climate is currently changing due to anthropogenic activities and the future with respect to weather patterns, storm strengths, and sea levels is highly uncertain. The chapters of this thesis consider multiple problems preventing accurate forecasting of coastal hazards, including difficulties linking climate to local impact, identifying oscillating trends within hazards, simulating hazards in efficient yet dynamics-based approaches, and the missing physics currently preventing nearshore erosion models from operating on management timescales.
Chapter 2 develops an approach for considering stochastic weather downscaled to the multiple processes contributing to elevated coastal water levels. Relatively short records of the full multi-dimensional space contributing to total water level (TWL) coastal flooding events (astronomic tides, sea level anomalies, storm surges, wave runup, etc.) results in historical observations of only a small fraction of the possible range of conditions that could produce severe flooding. The developed framework is capable of producing new iterations of the sea-state parameters associated with the present-day climate to simulate many synthetic extreme compound events. The emulator utilizes weather typing of fundamental climate drivers (sea surface temperatures, sea level pressures, etc.) to reduce complexity and produces new daily synoptic weather chronologies with an auto-regressive logistic model accounting for conditional dependencies on the El Niño Southern Oscillation (ENSO), the Madden-Julian Oscillation (MJO), seasonality, and the prior two days of weather progression. Joint probabilities of sea-state parameters unique to simulated weather patterns are used to simulate new time series of the hypothetical components contributing to synthetic TWLs. This work reveals the importance of considering the multi-variate nature of extreme coastal flooding, while progressing the ability to incorporate large-scale climate variability into site specific studies assessing hazards within the context of predicted climate change in the 21st century.
Chapter 3 couples the climate model of Chapter 2 with a surrogate model to efficient extrapolate spatially varying flood hazards. Numerical models for tides, surge, and wave runup have demonstrated ability to accurately define spatially varying flood surfaces. However, these models are often too computationally expensive to dynamically simulate the full parameter space of oceanographic, atmospheric, and hydrologic conditions that constructively compound in the nearshore. The hybrid statistical-dynamical modeling framework developed in Chapter 3 predicts spatially varying nearshore water levels contingent on any combination of forcing conditions. The hybrid framework can assess present day future coastal flood risk, including inundation depths, flooding frequencies, and wave-induced dune overtopping. The framework is demonstrated at Naval Base Coronado (NABC) in San Diego, CA, utilizing the regional flood model Coastal Storm Modeling System (CoSMoS; composed of Delft3D and XBeach) as a dynamic simulator and Gaussian process regression as a surrogate modeling tool. Validation of the framework uses both in-situ tide gauge observations within San Diego Bay, and a nearshore deployment of a cross-shore array of pressure sensors in the open beach surf zone. The complete approach can readily explore sensitivities to a wide range of resilience metrics, while capturing the uncertainty that exists in those metrics as a result of stochastic climate processes.
Chapter 4 uses a subset of the techniques from Chapter 1 to investigate interannual climate variability driving shoreline erosion. A recent 35-year endpoint shoreline change analysis revealed significant counterclockwise rotations occurring in north-central Oregon, USA, littoral cells that extend 10s of kilometers in length. While the potential for severe El Ninos to contribute to littoral cell rotations at seasonal to interannual scale was previously recognized, the dynamics resulting in persistent (multidecadal) rotation were unknown, largely due to a lack of historical wave conditions extending back multiple decades and the difficulty of separating the timescales of shoreline variability in a high energy region. This chapter addresses this question by (1) developing a statistical downscaling framework to characterize wave conditions relevant for longshore sediment transport during data-poor decades and (2) applying a one-line shoreline change model to quantitatively assess the potential for such large embayed beaches to rotate. A climate INdex was optimized to capture variability in longshore wave power as a proxy for potential LOngshore Sediment Transport (LOST_IN), and a procedure was developed to simulate many realizations of potential wave conditions from the index. Waves were transformed dynamically with Simulating Waves Nearshore to the nearshore as inputs to a one-line model that revealed shoreline rotations of embayed beaches at multiple time and spatial scales not previously discernible from infrequent observations. Model results indicate that littoral cells respond to both interannual and multidecadal oscillations, producing comparable shoreline excursions to extreme El Nino winters. The technique quantitatively relates morphodynamic forcing to specific climate patterns and has the potential to better identify and quantify coastal variability on timescales relevant to a changing climate.
Chapter 5 investigates the physical processes causing onshore sand bar migrations. Sand bars are morphological features that affect surf zone processes and ultimately the TWLs causing hazards, but their behavior currently can not be predicted on management time scales. Horizontal and vertical pressure gradients may be important physical mechanisms contributing to the onshore sediment transport beneath steep, near-breaking waves in the surf zone. A barred beach was constructed in a large-scale laboratory wave flume with a fixed profile containing a mobile sediment layer on the crest of the sandbar. Horizontal and vertical pore pressure gradients were obtained by finite differences of measurements from an array of pressure transducers buried within the upper several centimeters of the bed. Colocated observations of erosion depth were made during asymmetric wave trials with wave heights between 0.10 and 0.98 m, consistently resulting in onshore sheet flow sediment transport. The pore pressure gradient vector within the bed exhibited temporal rotations during each wave cycle, directed predominantly upward under the trough and then rapidly rotating onshore and downward as the wavefront passed. The magnitude of the pore pressure gradient during each phase of rotation was correlated with local wave steepness and relative depth. Momentary bed failures as deep as 20 grain diameters were coincident with sharp increases in the onshore-directed pore pressure gradients, but occurred at horizontal pressure gradients less than theoretical critical values for initiation of the motion for compact beds. An expression combining the effects of both horizontal and vertical pore pressure gradients with bed shear stress and soil stability is used to determine that failure of the bed is initiated at nonnegligible values of both forces.
Overall, this collection of manuscripts contributes to the goal of better predicting coastal hazards in the 21st century. Quantitatively linking climate phenomena to local coastal conditions and developing frameworks to efficiently make dynamical predictions of the resulting hazard is essential for understanding how climate change will impact vulnerable coastlines on policy and management time scales
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