Digital Commons Network^™

Performance Of Weedsoft For Predicting Soybean Yield Loss, Shawn M. Hock, Stevan Z. Knezevic, Alex Martin, John L. Lindquist

Department of Agronomy and Horticulture: Faculty Publications

Decision support systems (DSSs) have been developed to assist producers and consultants with weed management decisions. WeedSOFT is a DSS currently used in several states in the northcentral region of the United States. Accurate estimates of crop yield loss due to weed interference are required for cost-effective weed management recommendations. WeedSOFT uses competitive indices (CIs) to predict crop yield loss under multiple weed species, weed densities, and relative times of weed emergence. Performance of several WeedSOFT versions to predict soybean yield loss from weed competition was evaluated using CI values in WeedSOFT version 9.0 compared to new CI values calculated …

Soybean Row Spacing And Weed Emergence Time Influence Weed Competitiveness And Competitive Indices, Shawn M. Hock, Stevan Z. Knezevic, Alex Martin, John L. Lindquist

Department of Agronomy and Horticulture: Faculty Publications

Weed competitiveness can be quantified with the concept of competitive index (CI), a relative scale of weed competitiveness. Field studies were conducted in 2002 and 2003 in northeastern and southeastern Nebraska to evaluate the influence of soybean row spacing and relative weed emergence time on the competitiveness of major weed species in soybean. Ten weed species were seeded in soybean spaced 19 and 76 cm apart at the planting, emergence, and first trifoliate leaf stages of soybean. Total weed dry matter (TDM), weed plant volume, and percent soybean yield loss were arbitrarily selected as a base for determining the CI …

Predicting Biomass Partitioning To Root Versus Shoot In Corn And Velvetleaf (Abutilon Theophrasti), Kimberly D. Bonifas, John L. Lindquist

Department of Agronomy and Horticulture: Faculty Publications

Knowledge of how plants will partition their new biomass will aid in understanding competition between crops and weeds. This study determined if the amount of biomass partitioned to the root versus the shoot can be predicted from tissue carbon [C] and nitrogen [N] concentrations and the daily gain in C (G_C) and N (G_N) for each unit shoot and root biomass, respectively. Pots measuring 28 cm diameter and 60 cm deep were embedded in the ground, and each contained one plant of either corn or velvetleaf. Each plant received one of three nitrogen treatments: 0, 1, …

Simulated Insect Defoliation And Duration Of Weed Interference Affected Soybean Growth, Travis C. Gustafson, Stevan Z. Knezevic, Thomas E. Hunt, John L. Lindquist

Department of Agronomy and Horticulture: Faculty Publications

An improved understanding of crop stress from multiple pests is needed for better implementation of integrated pest management (IPM) strategies. Field studies were conducted in 2003 and 2004 at two locations in eastern Nebraska to describe the effects of simulated early-season insect defoliation of soybean and duration of weed interference on soybean growth. Three levels of simulated defoliation (undefoliated, 30, and 60%) and seven durations of weed interference (weedy and weed free; weed removal at V2, V4, V6, R3, and R5) were evaluated in a split-plot design. Defoliation significantly reduced soybean leaf-area index (LAI), total dry matter (TDM), and crop …

Early-Season Insect Defoliation Influences The Critical Time For Weed Removal In Soybean, Travis C. Gustafson, Stevan Z. Knezevic, Thomas E. Hunt, John L. Lindquist

Department of Agronomy and Horticulture: Faculty Publications

To develop more effective pest-management strategies, it is essential to understand how different pests interact with each other and the crop. Field studies were conducted in 2003 and 2004 at two Nebraska locations to determine the effects of early-season crop defoliation on the critical time for weed removal (CTWR) in narrow-row soybean. Three soybean defoliation levels were selected to simulate 0, 30, and 60% leaf tissue removal by the bean leaf beetle. Weeds were allowed to compete with the crop until V2, V4, V6, R3, and R5 growth stages. There were also season-long weedy and weed-free treatments. Results indicated that …

A Messaging System To Handle Semantic Dissonance, Ashish Rathod

Theses

Enterprises have been compelled to share their data internally and externally, but creating a consistent view of enterprise data has been challenging. Within a typical enterprise, each division uses its own domain specific data model and schema, and different enterprises obviously use their own data models and schema. Integrating these diverse data models and schemas, which have both syntactic and semantic differences, tends to be complex, slow, and inaccurate. Syntactic differences, i.e., differences in names or layout, have received substantial attention in research. Semantic dissonance simply means that the structure may be similar (or even the same) but the meaning …

Fast Time-Varying Dispersive Channel Estimation And Equalization For 8-Psk Cellular System, Sang-Yick Leong, Jingxian Wu, Chengshan Xiao, Jan C. Olivier

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, a novel channel-estimation scheme for an 8-PSK enhanced data rates for GSM evolution (EDGE) system with fast time-varying and frequency-selective fading channels is presented. via a mathematical derivation and simulation results, the channel impulse response (CIR) of the fast fading channel is modeled as a linear function of time during a radio burst in the EDGE system. Therefore, a least-squares-based method is proposed along with the modified burst structure for time-varying channel estimation. Given that the pilot-symbol blocks are located at the front and the end of the data block, the LS-based method is able to estimate …

Analysis Of Damage In Laminated Automotive Glazing Subjected To Simulated Head Impact, Shuangmei Zhao, Li Chai, S. D. Barbat, Lokeswarappa R. Dharani

Mechanical and Aerospace Engineering Faculty Research & Creative Works

During vehicle accidents, occupant's head impacting on windshield or side window is commonly observed. Any attempt to design glazing that minimizes injury to and death of occupants during a vehicle accident requires a thorough understanding of the mechanical behavior of automotive glazing subjected to head impact loads. A continuum damage mechanics (CDM) based constitutive model is developed and implemented into an axisymmetric finite element model to study the failure and impact resistance of laminated automotive glazing subjected to simulated head impact. An anisotropic elastic damage tensor with a linear damage evolution law is chosen to model the failure of the …

Creating Cross-Over Vehicles: Defining And Combining Vehicle Classes Using Shape Grammars, Seth D. Orsborn, R. Pawlicki, R. Smith, Jonathan Cagan

Mechanical and Aerospace Engineering Faculty Research & Creative Works

In the push for new vehicle designs, the distinctions between vehicle classes are quickly becoming blurred. We use shape grammars to quantify the differences between vehicle classes through the application of class-specific rules and the constraint of rule applications to within parametric ranges determined for each class. This allows for the development of new vehicle forms that clearly fall within a class or purposefully cross over the boundaries of classes and mix rules and ranges to create unique and interesting cross-over vehicles.

Effects Of Current On Droplet Generation And Arc Plasma In Gas Metal Arc Welding, J. Hu, Hai-Lung Tsai

Mechanical and Aerospace Engineering Faculty Research & Creative Works

In gas metal arc welding (GMAW), a technology using pulsed currents has been employed to achieve the one-droplet-per-pulse (ODPP) metal transfer mode with the advantages of low average currents, a stable and controllable droplet generation, and reduced spatter. In this paper, a comprehensive model was developed to study the effects of different current profiles on the droplet formation, plasma generation, metal transfer, and weld pool dynamics in GMAW. Five types of welding currents were studied, including two constant currents and three wave form currents. In each type, the transient temperature and velocity distributions of the arc plasma and the molten …

Neural Network Approach For Obstacle Avoidance In 3-D Environments For Uavs, Vivek Yadav, Xiaohua Wang, S. N. Balakrishnan

Mechanical and Aerospace Engineering Faculty Research & Creative Works

In this paper a controller design is proposed to get obstacle free trajectories in a three dimensional urban environment for unmanned air vehicles (UAVs). The controller has a two-layer architecture. In the upper layer, vision-inspired Grossberg neural network is proposed to get the shortest distance paths. In the bottom layer, a model predictive control (MPC) based controller is used to obtain dynamically feasible trajectories. Simulation results are presented for to demonstrate the potential of the approach.

Dynamic Re-Optimization Of A Spacecraft Attitude Controller In The Presence Of Uncertainties, Nishant Unnikrishnan, S. N. Balakrishnan, Radhakant Padhi

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Online trained neural networks have become popular in recent years in the design of robust and adaptive controllers for dynamic systems with uncertainties due to their universal function approximation capabilities. This paper discusses a technique that dynamically reoptimizes a Single Network Adaptive Critic (SNAC) based optimal controller in the presence of unmodeled plant uncertainties. The SNAC based optimal controller designed for the nominal plant model no more retains optimality in the presence of uncertainties/unmodeled dynamics that may creep up in the system equations during operation. This calls for a strategy to re-optimize the existing SNAC controller with respect to the …

Ethylene Could Influence Ferric Reductase, Iron Transporter, And H+-Atpase Gene Expression By Affecting Fer (Or Fer-Like) Gene Activity, Carlos Lucera, Brian M. Waters, Francisco Javier Romera, María José García, María Morales, Esteban Alcántara, Rafael Pérez-Vicente

Department of Agronomy and Horticulture: Faculty Publications

In previous works, it has been shown, by using ethylene inhibitors and precursors, that ethylene could participate in the regulation of the enhanced ferric reductase activity of Fe-deficient Strategy I plants. However, it was not known whether ethylene regulates the ferric reductase gene expression or other aspects related to this activity. This paper is a study of the effects of ethylene inhibitors and precursors on the expression of the genes encoding the ferric reductases and iron transporters of Arabidopsis thaliana (FRO2 and IRT1) and Lycopersicon esculentum (= Solanum lycopersicum) (FRO1 and IRT1) plants. The effects …

"To Integrate Or To Differentiate?" - Towards Resolving A Multi-Channel Dilemma Investigation Of The Effects Of Channel Integration Strategies On Consumers' Evaluations Of Multi-Channel Utility And Their Adoption Of Multi-Channel Shopping, Elena Kiryanova Bernard

LSU Doctoral Dissertations

Multi-channel retailers have been adopting different multi-channel formats that range from complete channel separation (e.g., Victoria's Secret) to close integration (e.g., Bed, Bath and Beyond). The purpose of this dissertation is to determine which multi-channel strategy offers the most value to multi-channel shoppers. The success of a multi-channel retailing strategy is believed to depend on the degree of channel complementarity as perceived by the retailer's customers. Channel complementarity is defined as the degree to which multiple retail channels work synergistically to create value. Complementary channels give customers integrated solutions that create more value than the sum of the parts. It …

"The Irresistible Force Meets The Immovable Object": When Antidiscrimination Standards And Religious Belief Collide In Aba-Accredited Law Schools, Kristin B. Gerdy

Faculty Scholarship

No abstract provided.

The Effects Of Cyber Courses On Southside Virginia Community College Student's Grade Point Averages, Kelley A. Barnes

OTS Master's Level Projects & Papers

To guide this problem, the following research hypothesis was established: 1. There will be no significant difference in students' grade point averages at Southside Virginia Community College when they are enrolled in classroom or cyber courses.

Academic Performance Of Students Who Receive Need-Based Financial Aid, Corey W. Carlson

OTS Master's Level Projects & Papers

To guide this research, the following hypothesis was established: 1. there is a positive difference in academic grade point average for students who receive need-based financial aid compared to those who do not receive need-based financial aid.

A Comparative Study Of The Effectiveness Of Distance Learning In Opticianry Education, Kristi Ostrom

OTS Master's Level Projects & Papers

To guide this study, the following hypothesis was established: 1. Within the members of the National Federation of Opticianry Schools that offer associate degree distance education programs via the internet for opticianry, there will be no difference in the number of students who will successfully complete their state licensure examinations.

Local Norms For Deaf And Hard-Of-Hearing Students, Kecia A. Boncek

Theses

Deafness is a low incident disability and therefore deaf children are frequently not included in the norm group of norm-referenced tests (Braden, 1994). The necessity of local norms is an ongoing debate among professionals who assess deaf children (Braden, 2005). This study evaluated the utility of local norms for three different intelligence tests. One sample t-tests were run to determine significance differences between means for a deaf and hard-of-hearing sample compared to the norm group, for the Differential Ability Scales (DAS), Universal Nonverbal Intelligence Test (UNIT), and the Wechsler Intelligence Scale for Children-Third Edition (WISC-III). Verbal cluster and Word Definition …

Parent Perceptions Of School Climate And Its Impact On Their Child's School Performance, Danielle Malinowski

Theses

This study compared the relationship of student and parent perceptions of school climate to the student's academic performance and school problem behaviors (disciplinary referrals, unexcused absences, and tardiness). A sample of students (n=531), grades 7-12, completed the School Climate Survey (Haynes et al., 1996). Additional information was obtained regarding each student's academic performance and school problem behaviors. A randomly selected sample of parents were sent the School Climate Survey,

Parent Edition and were asked to voluntarily return them (n=45). Correlation results found no significant relationship between parent and student perceptions of school climate. A significant relationship was found between Parent …

Perspective By Incongruity In Visual Advertising: Applying Kenneth Burke's Theory To The Adbusters Anti-Consumerism Campaign, Elizabeth B. Gorman

Theses

Kenneth Burke developed the theory of "perspective by incongruity" in which he claimed that oddly juxtaposed symbols influence audiences to have new perspectives by challenging their habits of thinking. This study applies Kenneth Burke's rhetorical theory of perspective by incongruity to the Adbusters anti-consumerism campaign. Twenty "spoof ad" postcards created by the Adbusters Media Foundation were analyzed to see how they utilize the technique of incongruous juxtaposition. The analysis concluded that the cards either juxtaposed two incongruous images, two incongruous phrases or words, or a combination of incongruous words and images in order to create new insights about consumer advertising …

School Climate: Comparing Student To Teacher Perceptions, Catherine S. Curione

Theses

The purpose of this study was to compare student and teacher perceptions of school climate. The participants included 51 junior and senior high school staff members, 256 senior high school students, and 109 junior high school students. It was found that teachers have strong positive views on the following school climate factors; school building, equity and fairness, and staff dedication to student learning. There is more disagreement among staff members on the following school climate factors; order and discipline, school/parent/community involvement, collaborative decision-making, and leadership. High School students do not take on a controlling role as far as school climate …

Controlling Performance Of Crumb Rubber-Modified Binders Through Addition Of Polymer Modifiers, Magdy Abdelrahman

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

The use of tire rubber as a modifier to enhance the properties of asphalt mixes through the wet process has proved to be a successful procedure, but full control of the properties of crumb rubber-modified binders has been a challenge. The literature indicates a wide variation on adding rubber to asphalt and that the degree of success of rubber modification in AC mixes depends on several factors, the majority of which relate to the method of mixing, storing, and transporting and to construction technologies. Understanding the nature of the interaction process between asphalt cement and crumb rubber-modifier (CRM) helps explain …

Effectiveness Of Open-Graded Base Layer On Subgrade Moisture Regime And Overall Pavement Performance, Hassan Salem, Fouad Bayomy, Robert Smith, Magdy Abdelrahman

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Rockcap (open-graded crushed aggregate with a nominal maximum size of 2.5 in.) base layer is commonly used in the construction of asphalt pavements in Idaho. The effectiveness of the rockcap layer on the subgrade moisture regime and the overall pavement performance were evaluated. Two pavement sites were selected in northern and southern regions of the state. At each site, two pavement sections that are identical and adjacent to each other were instrumented by temperature, frost, and moisture sensors using time domain reflectometry (TDR) probes. One was constructed by a well-graded 3/4-in. aggregate base, whereas the other was constructed by the …

Improving Prediction Accuracy In Mechanistic-Empirical Pavement Design Guide, Scott Schram, Magdy Abdelrahman

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Model calibration plays a fundamental role in the implementation of the mechanistic-empirical pavement design guide. The data used in the default calibration effort, which were afforded by the Long Term Pavement Performance (LTPP) database, have a network-level inference space. As implementation proceeds, state highway agencies may be inclined to calibrate at a local network level. However, with a focus on the calibration data set to local project-level conditions, model prediction error can be reduced further. Under this study, Nebraska Department of Roads Pavement Management System data were used to calibrate two design guide smoothness models at the local project level. …

Disinfection Of Swine Wastewater Using Chlorine, Ultraviolet Light And Ozone, John J. Macauley, Zhimin Qiang, Rao Y. Surampalli, Melanie R. Mormile, Craig D. Adams

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Veterinary antibiotics are widely used at concentrated animal feeding operations (CAFOs) to prevent disease and promote growth of livestock. However, the majority of antibiotics are excreted from animals in urine, feces, and manure. Consequently, the lagoons used to store these wastes can act as reservoirs of antibiotics and antibiotic-resistant bacteria. There is currently no regulation or control of these systems to prevent the spread of these bacteria and their genes for antibiotic resistance into other environments. This study was conducted to determine the disinfection potential of chlorine, ultraviolet light and ozone against swine lagoon bacteria. Results indicate that a chlorine …

Intelligent Optimal Control Of Excitation And Turbine Systems In Power Networks, Ganesh K. Venayagamoorthy, Ronald G. Harley

Electrical and Computer Engineering Faculty Research & Creative Works

The increasing complexity of the modern power grid highlights the need for advanced modeling and control techniques for effective control of excitation and turbine systems. The crucial factors affecting the modern power systems today is voltage control and system stabilization during small and large disturbances. Simulation studies and real-time laboratory experimental studies carried out are described and the results show the successful control of the power system excitation and turbine systems with adaptive and optimal neurocontrol approaches. Performances of the neurocontrollers are compared with the conventional PI controllers for damping under different operating conditions for small and large disturbances.

Calculating Static Field And Charge Distributions Using Full-Wave Boundary Element Methods, Todd H. Hubing, Haixin Ke

Electrical and Computer Engineering Faculty Research & Creative Works

No abstract provided.

Circuit Models For Power Bus Structures On Printed Circuit Boards Using A Hybrid Fem-Spice Method, Todd H. Hubing, Chunlei Guo

Electrical and Computer Engineering Faculty Research & Creative Works

Power bus structures consisting of two parallel conducting planes are widely used on high-speed printed circuit boards. In this paper, a full-wave finite-element method (FEM) method is used to analyze power bus structures, and the resulting matrix equations are converted to equivalent circuits that can be analyzed using SPICE programs. Using this method of combining FEM and SPICE, power bus structures of arbitrary shape can be modeled efficiently both in the time-domain and frequency-domain, along with the circuit components connected to the bus. Dielectric loss and losses due to the finite resistance of the power planes can also be modeled. …

Distributed Power Control For Cellular Networks In The Presence Of Channel Uncertainties, Maciej Jan Zawodniok, Q. Shang, Jagannathan Sarangapani

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, a novel distributed power control (DPC) scheme for cellular network in the presence of radio channel uncertainties such as path loss, shadowing, and Rayleigh fading is presented. Since these uncertainties can attenuate the received signal strength and can cause variations in the received Signal-to-Interference ratio (SIR), a new DPC scheme, which can estimate the slowly varying channel uncertainty, is proposed so that a target SIR at the receiver can be maintained. Further, the standard assumption of a constant interference during a link's power update used in other works in the literature is relaxed. A CDMA-based cellular network …