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Full-Text Articles in Operations Research, Systems Engineering and Industrial Engineering

Temporal Variations Of Water Productivity In Irrigated Corn: An Analysis Of Factors Influencing Yield And Water Use Across Central Nebraska, Tony Carr, Haishun Yang, Chittaranjan Ray Aug 2016

Temporal Variations Of Water Productivity In Irrigated Corn: An Analysis Of Factors Influencing Yield And Water Use Across Central Nebraska, Tony Carr, Haishun Yang, Chittaranjan Ray

Faculty Publications from The Water Center

Water Productivity (WP) of a crop defines the relationship between the economic or physical yield of the crop and its water use. With this concept it is possible to identify disproportionate water use or water-limited yield gaps and thereby support improvements in agricultural water management. However, too often important qualitative and quantitative environmental factors are not part of aWP analysis and therefore neglect the aspect of maintaining a sustainable agricultural system. In this study, we examine both the physical and economic WP in perspective with temporally changing environmental conditions. The physical WP analysis was performed by comparing simulated maximum attainable ...


A Five-Year Performance Review Of Field-Scale, Slow-Release Permanganate Candles With Recommendations For Second-Generation Improvements, Mark Christenson, Ann Kambhu, James Reece, Steve D. Comfort, Laurie Brunner Feb 2016

A Five-Year Performance Review Of Field-Scale, Slow-Release Permanganate Candles With Recommendations For Second-Generation Improvements, Mark Christenson, Ann Kambhu, James Reece, Steve D. Comfort, Laurie Brunner

Faculty Publications from The Water Center

In 2009, we identified a TCE plume at an abandoned landfill that was located in a low permeable siltyclay aquifer. To treat the TCE, we manufactured slow-release potassium permanganate cylinders (oxidant candles) that had diameters of either 5.1 or 7.6 cm and were 91.4 cm long. In 2010, we compared two methods of candle installation by inserting equal masses of the oxidant candles (7.6-cm vs 5.1-cm dia). The 5.1-cm dia candles were inserted with direct-push rods while the 7.6-cm candles were housed in screens and lowered into 10 permanent wells. Since installation, the ...


A Study On Facility Planning Using Discrete Event Simulation: Case Study Of A Grain Delivery Terminal., Sarah M. Asio Jul 2011

A Study On Facility Planning Using Discrete Event Simulation: Case Study Of A Grain Delivery Terminal., Sarah M. Asio

Industrial and Management Systems Engineering -- Dissertations and Student Research

The application of traditional approaches to the design of efficient facilities can be tedious and time consuming when uncertainty and a number of constraints exist. Queuing models and mathematical programming techniques are not able to capture the complex interaction between resources, the environment and space constraints for dynamic stochastic processes. In the following study discrete event simulation is applied to the facility planning process for a grain delivery terminal. The discrete event simulation approach has been applied to studies such as capacity planning and facility layout for a gasoline station and evaluating the resource requirements for a manufacturing facility. To ...


Why Divide By (N-1) For Sample Standard Deviation?, Paul Savory Jan 2008

Why Divide By (N-1) For Sample Standard Deviation?, Paul Savory

Industrial and Management Systems Engineering -- Instructional Materials

In statistics, the sample standard deviation is a widely used measure of the variability or dispersion of a data set. The standard deviation of a data set is the square root of its variance. In calculating the sample standard deviation, the divisor is the number of samples in the data set minus one (n-1) rather than n. This often confuses students. This paper offers a quick overview of why the divisor is (n-1) for calculating the sample standard deviation.


How Do You Interpret A Confidence Interval?, Paul Savory Jan 2008

How Do You Interpret A Confidence Interval?, Paul Savory

Industrial and Management Systems Engineering -- Instructional Materials

A confidence interval (CI) is an interval estimate of a population parameter. Instead of estimating the parameter by a single value, a point estimate, an interval likely to cover the parameter is developed. Many student incorrectly interpret the meaning of a confidence interval. This paper offers a quick overview of how to correctly interpret a confidence interval.


Assessment Of Squirrel-Caused Power Outages, J. Chris Hamilton, Ron J. Johnson, Ronald M. Case, Michael W. Riley Jan 1989

Assessment Of Squirrel-Caused Power Outages, J. Chris Hamilton, Ron J. Johnson, Ronald M. Case, Michael W. Riley

Papers in Natural Resources

Squirrel-caused power outages in Lincoln and Omaha, Nebraska, were evaluated by examining company power outage reports and by consulting with power company representatives. Reports showed that squirrel-caused outages at pole-mounted transformers were most prevalent during May, June, and October (48% of total) and between 1 and 4 h after sunrise (38%), patterns that coincide with squirrel dispersal or morning activity periods. In Lincoln, 1980 and 1981, squirrels caused 177 outages per year, which was 24% of all outages and 90% of animal-caused outages. Estimated minimum annual costs were $23 364 for repairs, public relations, and lost revenue while meters were ...