Engineering Commons^™

Clustered-Dot Periodic Halftone Screen Design And Icc Profile Color Table Compression, Chuohao Tang

Open Access Dissertations

This dissertation studies image quality problems associated with rendering images in devices like printing or displaying. It mainly includes two parts: clustered-dot periodic halftone screen design, and color table compression.

Screening is a widely used halftoning method. As a consequence of the lower resolution of digital presses and printers, the number of printer-addressable dots or holes in each microcell may be too few to provide the requisite number of tone lev- els between paper white and full colorant coverage. To address this limitation, the microcells can be grouped into supercells. The challenge is then to determine the desired supercell shape …

Fracture Analysis In Biomimetic Bouligand Architectures, Nobphadon Suksanqpanya

Open Access Dissertations

The Bouligand structure, which is found in many biological materials, is a hierarchical architecture that features uniaxial fiber layers assembled periodically into a helicoidal pattern. Many studies have highlighted the high damage-resistant performance of Bouligand structures and its biomimetic materials. One of the outstanding species with the Bouligand structures is the smashing Mantis Shrimp, Odontodactylus Scyllarus, (or stomatopod) due to its capability of generating high speed, high acceleration blows using its raptorial appendage to defeat highly armored preys. The load-bearing part of this appendage, the dactyl club, contains an interior region, which is mainly characterized by the Bouligand structure. This …

Geometric Accuracy Evaluation Of Mobile Terrestrial Lidar Surveys With Supporting Algorithms, Chisaphat Supunyachotsakul

Open Access Dissertations

Mobile Mapping System (MMS) technology is widely used for many applications, hence quantifying its accuracy is a very important and essential task and is a primary focus of this research. In general, to perfrom geometric accuracy evaluation of MMS data, validation points/features are needed. A method is needed to capture a point feature off the roadway in a position where a target on the ground surface would not be visible to the scanner. In this study, eight sphere targets with 14" diameter were placed on the shoulder of the roadway over validation points on the ground. The sphere targets were …

Policy Design Tool For Managing Indoor Residential Water Demand In Water-Scarce Regions, Mujahed M. Thneibat

Open Access Dissertations

In view of population growth; climate change; and economic evolution, water resources in numerous parts of the world have reached their natural capacities. Consequently, the ability of many countries to grow; meet the basic needs of inhabitants; and protect the environment will be endangered like never before unless water resources are smartly handled and managed. ^ In the past few decades, many developed and developing countries have suffered from water scarcity, and more are certain to follow. The water security dilemma is much more challenging in developing countries. Water utilities have had to follow regulatory plans to manage demand on …

Approximate Computing: An Integrated Cross-Layer Framework, Swagath Venkataramani

Open Access Dissertations

A new design approach, called approximate computing (AxC), leverages the flexibility provided by intrinsic application resilience to realize hardware or software implementations that are more efficient in energy or performance. Approximate computing techniques forsake exact (numerical or Boolean) equivalence in the execution of some of the application’s computations, while ensuring that the output quality is acceptable. While early efforts in approximate computing have demonstrated great potential, they consist of ad hoc techniques applied to a very narrow set of applications, leaving in question the applicability of approximate computing in a broader context.

The primary objective of this thesis is to …

Identifying And Prioritizing Critical Success Factors For Fixed Base Operators In The United States: A Mixed Method Approach, Yu Wang

Open Access Dissertations

Fixed Base Operators (FBOs) are major service providers for the general aviation (GA) sector, which closely connect the public with the aviation industry. However, over the past decade, the U.S. GA industry has experienced a decline in the numbers of registered aircraft, pilots, and airports. Due to the fact that FBOs significantly contribute to the aviation industry, further research studies regarding the FBO-sector at a national level are needed. The purpose of this dissertation was to identify and prioritize the critical success factors (CSFs) that promote the success of FBO operations in the United States.

The methodology consisted of a …

Fundamental Studies Of Flame Propagation In Lean-Burn Natural Gas Engines, Zhiyan Wang

Open Access Dissertations

Lean-burn natural gas engines offer enhanced thermal efficiencies and reduced soot and NOx emissions. However, cycle-to-cycle variability in combustion that can result from unreliable ignition, variability in equivalence ratio and quenching is a challenge. Reliability of ignition can be improved by employing a dual-fuel ignition strategy in which a small quantity of diesel fuel is injected to initiate ignition. Computational studies of n-heptane/methane-air mixing layers are performed to provide insight into the fundamental physics of dual-fuel ignition. The results show that the characteristic time required for steady premixed flame propagation has three components: time for autoignition to occur, time for …

On The Use Of Mechanical And Acoustical Excitations For Selective Heat Generation In Polymer-Bonded Energetic Materials, Daniel C. Woods

Open Access Dissertations

To address security issues in both military and civilian settings, there is a pressing need for improved explosives detection technologies suitable for trace vapor detection. In light of the strong dependence of vapor pressure on temperature, trace vapor detection capabilities may be enhanced by selectively heating target materials by external excitation. Moreover, polymer-bonded energetic materials may be particularly susceptible to heating by mechanical or acoustical excitation, due to the high levels of damping and low thermal conductivities of most polymers. In this work, the thermomechanical response of polymer-based energetic composites and methods for acoustical excitation are investigated in order to …

Matrix-Free Time-Domain Methods For General Electromagnetic Analysis, Jin Yan

Open Access Dissertations

Many engineering challenges demand an efficient computational solution of large-scale problems. If a computational method can be made free of matrix solutions, then it has a potential of solving very large scale problems. Among existing computational electromagnetic methods, the explicit finite-difference time-domain (FDTD) method is free of matrix solutions. However, it requires a structured orthogonal grid for space discretization. In this work, we develop a new time-domain method that naturally requires no matrix solution, regardless of whether the discretization is a structured grid or an unstructured mesh. No dual mesh, interpolation, projection and mass lumping are needed. Furthermore, a time-marching …

Computer Vision-Based Structural Assessment Exploiting Large Volumes Of Images, Chul Min Yeum

Open Access Dissertations

Visual assessment is a process to understand the state of a structure based on evaluations originating from visual information. Recent advances in computer vision to explore new sensors, sensing platforms and high-performance computing have shed light on the potential for vision-based visual assessment in civil engineering structures. The use of low-cost, high-resolution visual sensors in conjunction with mobile and aerial platforms can overcome spatial and temporal limitations typically associated with other forms of sensing in civil structures. Also, GPU-accelerated and parallel computing offer unprecedented speed and performance, accelerating processing the collected visual data. However, despite the enormous endeavor in past …

Photoelectrochemical And Photophysical Studies Of Carbon Nanotube And Molybdenum Disulfide Based Light Harvesting Devices, Hanyu Zhang

Open Access Dissertations

There is a critical need in utilizing solar radiation as a renewable energy source. While photovoltaic solar cells are widely used, much attention has been devoted in the past decade to developing nanotechnology for potential cost reduction and improved device efficiency and reliability. Low-dimensional materials offer unique physical properties which may be exploited for solar energy harvesting and conversion. Understanding their fundamental properties and developing relevant manufacturing strategies will thus pave the road toward high-performance, cost-effective, light-harvesting devices.

This thesis has investigated single-wall carbon nanotubes (SWCNTs) and molybdenum disulfide (MoS2) nanolayers for their light-harvesting ability in donor-acceptor systems. These materials …

Sugarcane Bagasse Hydrolysis Enhancement Using Bsa, Antonio Carlos Freitas Dos Santos

Open Access Theses

Lignocellulose is composed of polysaccharides linked to lignin and other aromatic compounds, making the sugars not readily available to fermentation. This entails that biomass must go through the unit operations of pretreatment and enzyme hydrolysis. Pretreatment opens the structure to allow the enzymes to act on and hydrolyze cellulose and hemicellulose to glucose and/or xylose which in turn are fermented to ethanol. Concomitantly, the enzymes interact with soluble phenols and insoluble solids derived from lignin that inhibit hydrolysis. This leads to high enzyme loadings and higher production costs. Soluble phenols can be eliminated through washing. Insoluble lignin, however, demands another …

Indiana Local Road And Bridge Conditions, Indiana Ltap

Indiana Local Technical Assistance Program (LTAP) Publications

In response to an appilcation requirement for the Community Matching Grant Fund Program, 354 asset management plans for roads and bridges were submitted in 2016 which contain the current conditions of local agency roads and bridges. This report describes these conditions and suggests the funding levels necessary to improve and maintain these assets at defined condition levels over a ten-year period. A ten-year horizon was used so as to correspond to previous LTAP studies performed in 2003 and 2009. The ten-year time period is also comparable to other Indiana studies.

Investigation Of Self-Organizing Traffic Signal Control With Graphical Signal Performance Measures, Christopher M. Day, Darcy M. Bullock

Lyles School of Civil Engineering Faculty Publications

Adaptive signal control is the subject of an increasing amount of research, as well as development and implementation. Most existing adaptive control systems achieve coordination by applying system control as a constraining layer on top of local control. Some researchers have suggested that, with the right local-control logic, coordination might be achieved as an dynamically emergent phenomenon without the need for a management layer. This paper explores the potential of a self-organizing signal control algorithm using a variety of performance measures. First, the initially reported algorithm performance is reproduced in an idealized environment; next, the algorithm is applied in a …

Scalable Dashboard For Identifying Split Failures And Heuristic For Reallocating Split Times, Howell Li, Lucy Richardson, Christopher M. Day, James Howard, Darcy M. Bullock

Lyles School of Civil Engineering Faculty Publications

The three fundamental parameters of a traffic signal system are split, cycle, and offset. This paper describes the use of high-resolution data (a) to identify time periods during which split parameters may be insufficient and (b) to help practitioners identify opportunities for reallocating split time. A case study of seven corridors with 47 intersections is presented. A drill-down approach was developed to identify movements that could be improved by a reallocation of split times. A heuristic that can reallocate up to 5 seconds of underutilized green time on a competing phase was applied to those corridors. …

Detector-Free Optimization Of Traffic Signal Offsets With Connected Vehicle Data, Cristopher Day, Howell Li, Lucy Richardson, James Howard, Tom Platte, Jim Sturdevant, Darcy M. Bullock

Lyles School of Civil Engineering Faculty Publications

It has recently been shown that signal offset optimization is feasible using vehicle trajectory data at low levels of market penetration. This study performs offset optimization on two corridors using this type ofdata. Six weeks oftrajectory splines were processed for two corridors including 25 signalized intersections, in order to create vehicle arrival profiles, using a proposed procedure called "virtual detection." After processing and filtering the data, penetration rates between 0.09-0.80% were observed, varying by approach. The arrival profiles were statistically compared against those measured with physical detectors, with the majority of the approaches showing statistically significant goodness-of-fit at a 90% …

Accident Rates, Phase Of Operations, And Injury Severity For Solo Students In Pursuit Of Private Pilot Certification (1994–2013), Douglas Boyd, Peter Dittmer

Journal of Aviation Technology and Engineering

Flight training accidents constitute 14% of general aviation accidents. Herein we determined the rates, injury severity, and phase of flight for primary student solo accidents/incidents (mishaps) in Cessna 172 aircraft.

Mishaps over the period spanning 1994–2013 were identified from the NTSB database. Student population data were from the FAA. Statistics employed proportion tests, Poisson distribution, and Mann-Whitney tests.

Across the study period, 598 mishaps were identified. While the mishap rate increased nearly two-fold between 1994/1997 and 2002/ 2005, a 35% decline was evident thereafter. Nevertheless, no statistical difference in mishap rates was evident between the initial and current periods. Over …

Designing Fixed-Base Operations Utilizing Systems Engineering Principles, Ross L. Stephenson Jr., David A. Carroll

Journal of Aviation Technology and Engineering

There are currently over 3,200 fixed-base operations (FBOs) conducting business in the United States attempting to meet the demands of FAA Part 91, Part 135, and a limited number of Part 121 operations. With the US economy slowly climbing out of the trough during 2013, the utilization of fixed-base operations has become more attractive and economical to the corporate business and the affluent recreational traveler. Despite the increased flight activities utilizing the services of fixed-base operators, keen competition, rising fuel cost, and the economies of scale recognized by large FBO franchises significantly erode the profitability and sustainability of smaller FBOs. …

Functional Mri In The Presence Of Repetitive, Sub-Concussive Impacts, Trey E. Shenk

Open Access Dissertations

Recent research has raised understanding and awareness of the long-term risks associated with mild traumatic brain injury (mTBI). While much research has focused on the role of concussion (a single event exhibiting clear clinical symptoms), the role of repetitive sub-concussive impacts is not well understood. This study uses functional MRI measurements of high school football players to identify functional changes, even in the absence of clinical symptoms.

The Purdue Agro-Climatic (Pac) Dataset For The U.S. Corn Belt: Development And Initial Results, Xing Liu, Elin Jacobs, Anil Kumar, Larry Biehl, Jeff Andersen, Dev Niyogi

Department of Earth, Atmospheric, and Planetary Sciences Faculty Publications

This study is a result of a project titled ‘‘Useful to Usable (U2U): Transforming Climate Variability and Change Information for Cereal Crop Producers”. This paper responds to the project goal to improve farm resiliency and proftability in the U.S. Corn Belt region by transforming existing meteorological dataset into usable knowledge and tools for the agricultural community.

A high-resolution agro-climatic dataset that covers the U.S. Corn Belt was built for the U2U project based on a Land Data Assimilation System (LDAS) framework. This data referred to as the Purdue Agro-climatic (PAC) dataset is a gridded, continuous dataset suitable for agrocli- matic …

Levitating Libraries To The Clouds: A Strategy For Academic Libraries, Mark Dehmlow

Charleston Library Conference

The University of Notre Dame’s Office of Information Technology is in the process of implementing a “Cloud First” strategy through which it intends to move 80% of its core technical infrastructure into the cloud by the end of 2017. The strategy advocates a tiered prioritization structure that recommends the hosting (SaaS) model for most services, the AWS (IaaS) model for fewer services, and finally on premises for a handful of the remaining services. As a campus technology partner, the Hesburgh Libraries has begun planning for moving many of our services and infrastructure into the cloud. This initiative represents a radical …

Can Flight Data Recorder Memory Be Stored On The Cloud?, Yair Wiseman

Journal of Aviation Technology and Engineering

Flight data recorders (FDRs, or black boxes) generate data that is collected on an embedded memory device. A well-known difficulty with these devices is that the embedded memory device runs out of space. To avoid getting into this problematic situation, the software of the FDR is designed to operate in a watchful mode, constantly working to minimize the use of memory space; otherwise a larger FDR would be needed. However, larger FDRs can be a problem because they have very rigorous requirements; thus, enlargement is costly. Outcomes of this research include the recommendation to send FDR data to a remote …

A Cellular Automation Which Incorporates Finite Element Method And Meshless Algorithm, Yong Cai, Zeyun Chen, Weifeng Yuan

The 8th International Conference on Physical and Numerical Simulation of Materials Processing

No abstract provided.

Effect Of Preparation Technology On Arc Erosion Resistance Of Mgo/Cu Contact Materials, Xiuhua Guo, Kexing Song, Yanmin Zhang, Xuebin Zhang, Jianxin Gao

The 8th International Conference on Physical and Numerical Simulation of Materials Processing

No abstract provided.

Cement Asphalt Mortar Modelling And Its Influence On High-Speed Train–Bridge System In Presence Of Moderate Earthquakes And Service Loading, Lingkun Chen

The 8th International Conference on Physical and Numerical Simulation of Materials Processing

No abstract provided.

Nondestructive Testing And Structural Health Monitoring Based On Adams And Svm Techniques, Gang Jiang, Yi Ming Deng, Ji Tai Niu

The 8th International Conference on Physical and Numerical Simulation of Materials Processing

No abstract provided.

Thermodynamic Calculation Of The Liquidus Surface Projection Of Multi-Component Aluminum Alloys, Jingrui Zhao, Yong Du, Lijun Zhang, Jixue Zhou, Yuansheng Yang

The 8th International Conference on Physical and Numerical Simulation of Materials Processing

No abstract provided.

A356 Aluminum Alloy, Grain Refining, Modification, Microstructure, Mechanical Properties, Jonghun Yoon

The 8th International Conference on Physical and Numerical Simulation of Materials Processing

No abstract provided.

A Molecular Dynamics Study Of Activated Tungsten Inert Gas Welding Process, Cheng Jin, Hanchen Huang

The 8th International Conference on Physical and Numerical Simulation of Materials Processing

No abstract provided.

Novel Closed-Loop Control Strategy For Inkjet-Based Additive Manufacturing System, Yunong Shi, Chunsheng Ye

The 8th International Conference on Physical and Numerical Simulation of Materials Processing

No abstract provided.