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Articles 1 - 14 of 14
Full-Text Articles in Engineering
Computation Of Risk Measures In Finance And Parallel Real-Time Scheduling, Yajuan Li
Computation Of Risk Measures In Finance And Parallel Real-Time Scheduling, Yajuan Li
Dissertations
Many application areas employ various risk measures, such as a quantile, to assess risks. For example, in finance, risk managers employ a quantile to help determine appropriate levels of capital needed to be able to absorb (with high probability) large unexpected losses in credit portfolios comprising loans, bonds, and other financial instruments subject to default. This dissertation discusses the computation of risk measures in finance and parallel real-time scheduling.
Firstly, two estimation approaches are compared for one risk measure, a quantile, via randomized quasi-Monte Carlo (RQMC) in an asymptotic setting where the number of randomizations for RQMC grows large, but …
Optimizing Speed Profiles For Sustainable Train Operation With Wayside Energy Storage Systems, Leon A. Allen
Optimizing Speed Profiles For Sustainable Train Operation With Wayside Energy Storage Systems, Leon A. Allen
Dissertations
Large hauling capability and low rolling resistance has put rail transit at the forefront of mass transportation mode sustainability in terms of congestion mitigation and energy conservation. As such, rail vehicles are one of the least energy-intensive modes of transportation and least environmentally polluting. Despite, these positives, improper driving habits and wastage of the braking energy through dissipation in braking resistors result in unnecessary consumption, extra costs to the operator and increased atmospheric greenhouse gas emissions.
This study presents an intelligent method for the optimization of the number and locations of wayside energy storage system (WESS) units that maximize the …
Resource Allocation For Heterogeneous Wireless Networks Of Devices With Multi-Connectivity, Monika Prakash
Resource Allocation For Heterogeneous Wireless Networks Of Devices With Multi-Connectivity, Monika Prakash
Dissertations
This dissertation contributes to designing an effective resource allocation scheme for multi-connectivity (MC) networks. MC is a feature that allows devices to utilize the radio resources from more than one base station simultaneously. With MC anticipated to play a key role in satisfying the stringent QoS requirements of the next-generation networks (5G/6G), it is crucial to efficiently allocate the resources across multiple connections of one or more radio access technologies (RATs).
Currently, there is a huge demand on the availability of radio spectrum resources with a large volume of different types of data traffic (Internet-of-things, human-based, machine-machine) traversing the internet. …
Evaluation Of Data Collection Operations For Real-Time Influenza Surveillance During An Emergency, Yuwen Gu
Evaluation Of Data Collection Operations For Real-Time Influenza Surveillance During An Emergency, Yuwen Gu
Dissertations
It is unclear how data collection operations for surveillance alter the disease portrayal that influenza reported trends attempt to provide during an emergency. This study developed a model that simulates the collection and testing of influenza specimens after an outbreak is declared in Michigan. It performed simulation based optimization to understand which operational factors affect the biases between the growth rates of original and observed influenza incidence trends, and to quantify the predictive power of the influenza incidence trends at different points of data collection. The results show that emergency driven high risk perception increases the reporting, which leads to …
Simulation, Performance And Interference Analysis Of Multi-User Visible Light Communication Systems, Adel Aldalbahi
Simulation, Performance And Interference Analysis Of Multi-User Visible Light Communication Systems, Adel Aldalbahi
Dissertations
The emergence of new physical media such as optical wireless, and the ability to aggregate these new media with legacy networks motivate the study of heterogeneous network performance, especially with respect to the design of protocols to best exploit the characteristics of each medium.
This study considers Visible Light Communications (VLC), which is expected to coexist with legacy and future radio frequency (RF) media. While most of the research on VLC has been done on optimizing the physical medium, research on higher network layers is only beginning to gain attention, requiring new analyses and tools for performance analysis.
The first …
Experimental And Modeling Studies In Membrane Distillation, Lin Li
Experimental And Modeling Studies In Membrane Distillation, Lin Li
Dissertations
A variety of microporous hydrophobic flat sheet membranes of polyvinylidene fluoride (PVDF) and expanded-polytetrafluoroethylene (e-PTFE) are studied to evaluate the influence of membrane properties on their performance in desalination by direct contact membrane distillation (DCMD) and vacuum membrane distillation (VMD) processes. The membrane thickness is varied between 23 μm to 125 μm; the pore size is varied from 0.05 μm to 0.45 μm. The porosity is generally high in the range of 0.7 - 0.8. DCMD experiments are performed over a hot brine temperature range of 65 °C to 85 °C and distillate temperature at 25 °C for various brine …
Understanding Bulk Behavior Of Particulate Materials From Particle Scale Simulations, Xiaoliang Deng
Understanding Bulk Behavior Of Particulate Materials From Particle Scale Simulations, Xiaoliang Deng
Dissertations
Particulate materials play an increasingly significant role in various industries, such as pharmaceutical manufacturing, food, mining, and civil engineering. The objective of this research is to better understand bulk behaviors of particulate materials from particle scale simulations.
Packing properties of assembly of particles are investigated first, focusing on the effects of particle size, surface energy, and aspect ratio on the coordination number, porosity, and packing structures. The simulation results show that particle sizes, surface energy, and aspect ratio all influence the porosity of packing to various degrees. The heterogeneous force networks within particle assembly under external compressive loading are investigated …
Analyses Of Groundwater Contribution To A Riverine Wetland, Farzad Mahmoodinobar
Analyses Of Groundwater Contribution To A Riverine Wetland, Farzad Mahmoodinobar
Dissertations
Rainfall, runoff, overbank flow and groundwater, all contribute water to wetlands. Each transport element is associated with unique modeling approaches and uncertainties. Transpiration is perhaps the hardest to quantify as it is subject to all the variability of plant growth. Transpiration causes land area to lose moisture and the loss amount depends on precipitation incidence, the temperature and type and extent of vegetation. Plants can intercept virtually all recharge during the growing season and almost none from late fall to early spring in northeastern United States. Thus, an improvement in the transpiration element can contribute considerably to an improved groundwater …
Discrete Element Method Based Scale-Up Model For Material Synthesis Using Ball Milling, Priya Radhi Santhanam
Discrete Element Method Based Scale-Up Model For Material Synthesis Using Ball Milling, Priya Radhi Santhanam
Dissertations
Mechanical milling is a widely used technique for powder processing in various areas. In this work, a scale-up model for describing this ball milling process is developed. The thesis is a combination of experimental and modeling efforts.
Initially, Discrete Element Model (DEM) is used to describe energy transfer from milling tools to the milled powder for shaker, planetary, and attritor mills. The rolling and static friction coefficients are determined experimentally. Computations predict a quasi- steady rate of energy dissipation, Ed, for each experimental configuration. It is proposed that the milling dose defined as a product of Ed and milling …
Inkjet Printability Of Electronic Materials Important To The Manufacture Of Fully Printed Otfts, Sooman Lim
Inkjet Printability Of Electronic Materials Important To The Manufacture Of Fully Printed Otfts, Sooman Lim
Dissertations
In this study, the inkjet printability of materials important to fabricating OTFTs was researched. In order to understand the jetting evolution of inkjet printed inks, simulations were performed with a nano copper and nano particle silver ink. To predict the inkjettability of the nano copper ink, Z and Oh numbers at different temperatures were determined. The results from the simulation studies were compared to experimental results obtained using a Dimatix inkjet printer. For the semiconductor ink, the inkjet printability of two organic semiconductors, P2TDC17FT4 (poly[(3,7-diheptadecylthieno[3,2-b]thieno[2',3':4,5]thieno[2,3-d]thiophene-2,6-diyl)[2,2'-bithiophene]-5,5'-diyl] dissolved in 1,2-dichlorobenzene and P3HT (poly-3 hexylthiophene) were compared to determine the relationship between drop …
Design Of Novel Drug Delivery System And Optimal Dosage Regimens, Kwang Seok Kim
Design Of Novel Drug Delivery System And Optimal Dosage Regimens, Kwang Seok Kim
Dissertations
Three representative drug delivery systems were analyzed to emphasize the roles of mathematical models and computer-aided simulations in pharmaceutical research. In the first project, a protocol was developed so that the optimal regimen, consisting of the intravenous boluses and subsequent infusion of theophylline, could be obtained once information on the pharmacokinetics became available. The method was based on a two-compartment model of the human body. A module was created and posted on a website for free access. The second project dealt with the transdermal heat-assisted delivery of corticosterone. Heat conduction and drug diffusion through the patch and the skin were …
Evaporating Cross Flow Spray Jets In Gas-Solid Circulating Fluidized Bed, Tong Hoon Lee
Evaporating Cross Flow Spray Jets In Gas-Solid Circulating Fluidized Bed, Tong Hoon Lee
Dissertations
Three-phase flow of solid-gas suspension with liquid spray is found in many industrial applications, including fluidized catalytic cracking in petroleum refinery process, and wet scrubbing process. This dissertation study is aimed to understand the gas-solid-liquid three-phase flow structure, phase interactions and transport in a gas-solid circulating fluidized bed where an evaporating cross-flow liquid spray jet from a rectangular nozzle with a fan angle is injected. The investigation is based on both numerical and experimental approaches. The numerical study is for detailed field descriptions of the flow structure, phase interaction and distributions whereas the experimental study is for simulation validations. The …
Migration Of An Intruder Particle In A Boundary Driven Shear Flow, Jian Liu
Migration Of An Intruder Particle In A Boundary Driven Shear Flow, Jian Liu
Dissertations
This study reports on three-dimensional, discrete element simulations of a single large spherical intruder in a Couette shear flow composed of uniform sized particles. The simulation results are useful in providing a numerical reproduction of the experiments for size segregation and mixing. This in turn has a major importance in many industries which are concerned with handling of particles and powders, such as pharmaceutical manufacturing, agriculture, chemical and mineral processing.
Discrete element simulations are carried out using the "soft sphere" model of Walton, et. al., which provides a method for obtaining the information at a macroscopic level from multi-body collisions …
The Use Of A Water Quality Model To Evaluate The Impacts Of Combined Sewer Overflows On The Lower Hudson River, Wen-Pin Shu
The Use Of A Water Quality Model To Evaluate The Impacts Of Combined Sewer Overflows On The Lower Hudson River, Wen-Pin Shu
Dissertations
CSO discharges have long been recognized as a significant source of water pollution. While many sources of water pollution have been controlled over the past 20 years, CSOs continue to be a main environmental concern in several areas, especially in old cities. In the past, most CSO research focused on the CSO control processes, including floatables and suspended solids removal. Few studies have been conducted in the area of the impacts of CSO discharge on the receiving water quality. To achieve this purpose, a powerful water-modeling tool, WASP 6.1, is utilized in this study. The Lower Hudson River is selected …