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Full-Text Articles in Engineering

Model Based Analysis Of The Accuracy And Precision Of Auscultatory Blood Pressure Measurements In Patients With Atrial Fibrillation, Charles F. Babbs Sep 2019

Model Based Analysis Of The Accuracy And Precision Of Auscultatory Blood Pressure Measurements In Patients With Atrial Fibrillation, Charles F. Babbs

Weldon School of Biomedical Engineering Faculty Working Papers

Accurate measurement of blood pressure in the presence of atrial fibrillation remains an open problem. The present study combines the techniques of stochastic mathematical modeling with physiological models of the systemic circulation, cuff, and arm (1) to explore mechanisms underlying both the lack of accuracy and the lack of precision in cuff-based arterial pressure measurements during atrial fibrillation and (2) to develop strategies to correct for errors. Both the cardiovascular system and the measurement technique are described using mathematics, including both numerical techniques and analytical probability theory. Preliminary results with numerical models suggested that, despite variability, average systolic pressures tend …


Computations Of Top-Down Attention By Modulating V1 Dynamics, David Berga, Xavier Otazu May 2019

Computations Of Top-Down Attention By Modulating V1 Dynamics, David Berga, Xavier Otazu

MODVIS Workshop

The human visual system processes information defining what is visually conspicuous (saliency) to our perception, guiding eye movements towards certain objects depending on scene context and its feature characteristics. However, attention has been known to be biased by top-down influences (relevance), which define voluntary eye movements driven by goal-directed behavior and memory. We propose a unified model of the visual cortex able to predict, among other effects, top-down visual attention and saccadic eye movements. First, we simulate activations of early mechanisms of the visual system (RGC/LGN), by processing distinct image chromatic opponencies with Gabor-like filters. Second, we use a cortical …


Perception Of 3d Symmetrical And Near-Symmetrical Shapes, Vijai Jayadevan, Aaron Michaux, Edward Delp, Zygmunt Pizlo May 2017

Perception Of 3d Symmetrical And Near-Symmetrical Shapes, Vijai Jayadevan, Aaron Michaux, Edward Delp, Zygmunt Pizlo

MODVIS Workshop

No abstract provided.


Influence Of Fly Ash On Surface Chloride Concentration Under Shallow Immersion Condition, Jun Liu, Xiaodong Wang, Feng Xing, Ningxu Han Jul 2014

Influence Of Fly Ash On Surface Chloride Concentration Under Shallow Immersion Condition, Jun Liu, Xiaodong Wang, Feng Xing, Ningxu Han

International Conference on Durability of Concrete Structures

In this paper, the influence of fly ash content on concrete surface chloride concentration was investigated through periodical tests of surface chloride concentration of concrete by immersing three kinds of concrete specimens in 5.0 wt.% sodium chloride solution. One kind of specimen is common concrete without fly ash, whereas the other two kinds of specimens are mixed with fly ash. The results show that the surface chloride ion concentration ranges from 0.295 to 0.777 wt.% for the immersed concrete samples in this study; in the initial stage of immersion, the concrete surface chloride ion concentration is affected by added fly …


Modeling Target Disinfection By-Product Dynamics In Indoor Swimming Pools, Barnard S. Mondal, Cary Troy, Mehrnaz Afifi, Shih-Chi Weng, Ernest R. Blatchley Iii Oct 2013

Modeling Target Disinfection By-Product Dynamics In Indoor Swimming Pools, Barnard S. Mondal, Cary Troy, Mehrnaz Afifi, Shih-Chi Weng, Ernest R. Blatchley Iii

The Summer Undergraduate Research Fellowship (SURF) Symposium

Chlorination is the primary disinfection method for swimming pools in the United States; however, chlorine also reacts with pollutants (e.g., sweat, urine and anthropogenic compounds) to form disinfection by-products (DBPs). Some DBPs are asthma causing (e.g. nitrogen-trichloride) and even carcinogens (e.g., trihalomethanes and nitrosamines). Consequently, exposure to DBPs poses health risks to patrons and staff in pool environments. Furthermore, volatilization of DBPs is enhanced by bather activity, but the relationship between activity and volatilization has yet been quantified such that the dynamic behavior of DBPs can be predicted. Therefore, the objective of this research is to …


Model County Subdivision Regulations, T. William Patterson Jan 1989

Model County Subdivision Regulations, T. William Patterson

Indiana Local Technical Assistance Program (LTAP) Publications

This HERPICC model is intended as a basis for helping Indiana counties, cities, and towns to write or revise local regulatory ordinances.