USING ISOTONIC REGRESSION TO IMPROVE ESTIMATION IN FACTORIAL EXPERIMENTS WITH ORDERED FACTOR LEVELS

In many designed experiments in agriculture and the life sciences, a researcher can anticipate the direction that responses will take when treatments are varied. For example, in a 2-way factorial, a researcher may know that increasing the levels of nitrogen and phosphorus will increase yields of a crop. Classical analysis of variance does not take into account a known ordering among population means. However, it can be shown that by restricting the estimates of means to have the same ordering as the anticipated ordering of population means, a reduction in mean-squared errors of estimators will likely occur, often by more than 50%. A procedure used to create such estimates is called isotonic regression. In this article, a recently proposed method of isotonic regression for lattice-ordered means will be presented after first reviewing well-established methods. The newer method will be illustrated using data from an entomology experiment. In addition, standard errors of the estimators will be approximated using a bootstrap procedure

A Simple Effective Method for Three-Dimensional Modelling of Cementation, Fracturing and Dissolution of Carbonate Rocks: Illustrated through Oolitic Limestone

Sandstones and many carbonates (e.g., oolitic limestone and other grainstones), comprise solid particulates (grains) and pores, which have a given pore network architecture relationship, and associated porosity—permeability values. Over time, through the process of diagenesis, the pore network architecture may be extensively altered. Changes can include compaction, particle deformation, cementation, dissolution and fracturing, with the pathway followed after deposition depending on factors such as the energy level, rate of burial, degree of biological activity, local heat flow, sediment composition, Eh, pH and the presence or absence of organic materials. Any method that provides a means of modelling changes is therefore highly desirable, in particular, allowing a prediction of changes in porosity and permeability with time. The current work illustrates a simple method that uses freely available open source image analysis software to model the development of cement phases within an oolitic limestone in three-dimensions. As well as cementation, it demonstrates the modelling of fracture development and dissolution processes, and records how porosity and permeability change during such processes

Automating the Verification of the Low Voltage Network Cables and Topologies

Low Voltage (LV) networks are increasingly required to cope with challenges they were not designed for, requiring for more active network management (ANM). Crucially, ANM solutions require the availability of accurate network information. In practice, available data on LV networks can be incomplete, a problem often overlooked in prior ANM research. For example, in the U.K. and many developed countries, the lifetime of distribution networks assets spans several decades, with some of the available asset data gathered and maintained over many years. This can often lead to incomplete cable data being available to network operators. To overcome this, we propose a novel machine learning technique to autonomously approximate the missing cable information in LV networks. Our proposed algorithm uses a tree-based search methodology, which approximates the missing cable's cross section area (XSA) data based on rules engineers used when designing the LV networks. We validate our approach using a large database of real LV networks, where some of the cables' XSA are treated as unknown and used as ground truth to evaluate the accuracy of the predictions. Moreover, we propose a mechanism that scores the confidence level of the prediction, information which is then presented to the human network planners

Nano Vacuum Channel Transistors (NVCT)

The goal of Nano Channel Vacuum Transistor (NVCT) research is to develop and characterize three-terminal vacuum transistor devices that operate in ultra-high vacuum (UHV) and withstand temperatures up to 400 °C. The transistors consist of an insulated gate, an emitter array, and a collector. To avoid overheating the collector, the gate is pulsed from 0 to 40 V at a duty cycle of 10-20% while the emitter and collector are fixed DC voltages of 0V and 100 V, respectively. Current from emitter to collector is measured to obtain an output current – input voltage plot (I-V curve). The devices are heated using a molybdenum chuck inside the UHV chamber. After preliminary tests, the devices are moved to the UHV lifetime test chamber and run with pulsed gate voltage with fixed amplitude at constant temperature for hundreds of hours. Periodic IV sweeps are also conducted to observe changes. Factors such as overheating and arcing can lead to device degradation or failure. The goals of the project include designing driver systems for the devices, implementing automated Data Acquisition (DAQ) hardware to control and monitor testing systems, and using data to characterize the devices and determine approximate lifetime, maximum operating conditions, and failure conditions

A Waterborne Outbreak of Escherichia coli O157:H7 Infections and Hemolytic Uremic Syndrome: Implications for Rural Water Systems1

In the summer of 1998, a large outbreak of Escherichia coli O157:H7 infections occurred in Alpine, Wyoming. We identified 157 ill persons; stool from 71 (45%) yielded E. coli O157:H7. In two cohort studies, illness was significantly associated with drinking municipal water (town residents: adjusted odds ratio=10.1, 95% confidence intervals [CI]=1.8-56.4; visitors attending family reunion: relative risk=9.0, 95% CI=1.3-63.3). The unchlorinated water supply had microbiologic evidence of fecal organisms and the potential for chronic contamination with surface water. Among persons exposed to water, the attack rate was significantly lower in town residents than in visitors (23% vs. 50%, p<0.01) and decreased with increasing age. The lower attack rate among exposed residents, especially adults, is consistent with the acquisition of partial immunity following long-term exposure. Serologic data, although limited, may support this finding. Contamination of small, unprotected water systems may be an increasing public health risk

Reflection and tunneling of ocean waves observed at a submarine canyon

Author Posting. © American Geophysical Union, 2005. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geophysical Research Letters 32 (2005): L10602, doi:10.1029/2005GL022834.Ocean surface gravity waves with periods between 20 and 200 s were observed to reflect from a steep-walled submarine canyon. Observations of pressure and velocity on each side of the canyon were decomposed into incident waves arriving from distant sources, waves reflected by the canyon, and waves transmitted across the canyon. The observed reflection is consistent with longwave theory, and distinguishes between cases of normal and oblique angles of incidence. As much as 60% of the energy of waves approaching the canyon normal to its axis was reflected, except for waves twice as long as the canyon width, which were transmitted across with no reflection. Although waves approaching the canyon at oblique angles cannot propagate over the canyon, total reflection was observed only at frequencies higher than 20 mHz, with lower frequency energy partially transmitted across, analogous to the quantum tunneling of a free particle through a classically impenetrable barrier.Funding was provided by the Office of Naval Research and the National Science Foundation

TurboExpander Wheel Damage Analysis: A Case Study

Case StudyCS8Damage analysis of a turbo-expander wheel in a geothermal application will be discussed. Presentation includes: background, description of damage, damage analysis, conclusions, and finally discussion of remedial actions to achieve longer life for the wheel

Getting It on Record: Issues and Strategies for Ethnographic Practice in Recording Studios

The recording studio has been somewhat neglected as a site for ethnographic fieldwork in the field of ethno-musicology and, moreover, the majority of published studies tend to overlook the specific concerns faced by the researcher within these contexts. Music recording studios can be places of creativity, artistry, and collaboration, but they often also involve challenging, intimidating, and fractious relations. Given that recording studios are, first and foremost, concerned with documenting musicians’ performances, we discuss the concerns of getting studio interactions “on record” in terms of access, social relations, and methods of data collection. This article reflects on some of the issues we faced when conducting our fieldwork within British music recording facilities and makes suggestions based on strategies that we employed to address these issues