Honoring and Maintaining a Dual Identity

My father taught at a church-affiliated college as a professor of philosophy. My mother, for much of my growing-up years, was a fifth-grade public school teacher. Although I was shaped by both of these models, and attracted to each, I initially came down on the side of elementary teaching. For close to 10 years I worked, mostly happily, with upper-elementary children in both public and private settings. Professionally, at least, I seemed to have much more to talk about with my mother. Having subsequently completed a doctorate in the history of education (including much formal and informal study of philosophy) and having taught now for 15 years at a small Christian liberal arts college, friends often point out how much my life resembles that of my father

Search, choice, and revealed preference

With complete information, choice of one option over another conveys preference. Yet when search is incomplete, this is not necessarily the case. It may instead reflect unawareness that a superior alternative was available. To separate these phenomena, we consider non-standard data on the evolution of provisional choices with contemplation time. We characterize precisely when the resulting data could have been generated by a general form of sequential search. We characterize also search that terminates based on a reservation utility stopping rule. We outline an experimental design that captures provisional choices in the pre-decision period.Revealed preference, search theory, stochastic choice

Design of a processor to support the teaching of computer systems

Teaching computer systems, including computer architecture, assembly language programming and operating system implementation, is a challenging occupation. At the University of Waikato this is made doubly true because we require all computer science and information systems students study this material at second year. The challenges of teaching difficult material to a wide range of students have driven us to find ways of making the material more accessible. The corner stone of our strategy for delivering this material is the design and implementation of a custom CPU that meets the needs of teaching. This paper describes our motivation and these needs. We present the CPU and board design and describe the implementation of the CPU in an FPGA. The paper also includes some reflections on the use of a real CPU rather than a simulation environment. We conclude with a discussion of how the CPU can be used for advanced classes in computer architecture and a description of the current status of the project

A Comparison of Models for the Fulton-Macpherson Operads

In this thesis we explore the structure of the Fulton-Macpherson operads F_N by providing two new models for them. It is shown in work of Salvatore that these operads are cofibrant by claiming the existence of an isomorphism of operads from WF_N to F_N. Here, W is a functor which, for a large class of topological operads, produces cofibrant replacements. It would be satisfying to be able to write down explicitly what these isomorphisms are. Our new models are an attempt to move towards this. The building blocks of the first model appeared in the Ph.D. thesis of Daniel Singh but they were not assembled into an operad here. This model has a more algebraic feel than others in the literature which gives it technical advantages. We use this to demonstrate many of the well-known properties of the Fulton-Macpherson operads. In particular, we are able to write down explicit isomorphisms between F_1 and the Stasheff operad which we have not seen previously in the literature. This model is isomorphic to other models of the Fulton-Macpherson operads. The second model is a realisation of an operad in posets. This poset operad is built from combinatorial objects called chains of preorders. These objects encode maps from a finite set A to some Euclidean space R^N. In particular, we can impose restrictions to encode injective maps of this type. This model is equivalent up to homotopy to the Fulton-Macpherson operads in a way which we define. It is also homotopy equivalent to the Smith operads, another example of topological operads defined combinatorially. The main advantage of this model is that it has an obvious spine which may pave the way to writing down the desired isomorphisms from WF_N to F_N

Second moment characterization of agricultural export and income projection models

Agricultural outlook baseline projections published by FAPRI, USDA and the OECD are intended as policy analysis tools. It is shown that projections have been used as forecasts. Therefore, users of baseline projections need information about the past performance of baseline projections. This thesis measures the projection errors of baseline projections using RMSE and MAPE and assesses the ability of models to predict directional movements. The baseline model results are compared to corresponding results of naive models. For projection errors, a mixed model is used to estimate the mean bias and confidence intervals about the mean. Projections of corn, soybean, wheat, beef and pork exports, corn, soybean and wheat farm prices and direct government farm payments are analyzed. Results from the baseline models are compared to the corresponding results from naive models. This analysis shows that baseline projections are not consistently superior to naive models in projecting the future export and price levels. For soybean, beef and pork exports and for corn, soybean and wheat prices, baseline projections have been shown to perform relatively well. However, baseline projections for corn and wheat exports and government payments models have relatively large RMSE and bias. It is important for the users of baseline projections to understand the assumptions and structure of the models. Projection users and funding agencies need to be aware of the magnitude and direction of projection errors and bias. Modelers need to update and refine models based on the results of past projection analyses to produce better projections given the baseline assumptions. Additionally, organizations should more strongly explain the proper use and limitations of baseline projections

Nanoscale silver: Thin-film structure and antimicrobial functionality

Since antiquity, silver has been used as a material to reduce spoilage. Over the past decades, there has been an increasing scientific and commercial interest in developing silver surfaces due to the increasing number of drug resistant microorganisms. In this study, the effect of nanostructuring silver films as an antimicrobial against the bacteria Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) was examined. Films consisting of 3 nm chromium adhesion layers and nominal 20 nm silver surfaces (assuming flat deposition) were deposited by thermal evaporation and nanostructuring was controlled by varying the incident angle of the silver onto the substrate. Four substrate angles were used including 0 °, 18 °, 40 ° and 70 ° to the horizontal. Examination by atomic force microscope, Rutherford backscattering and ellipsometry showed that as the incident angle of deposition increased, so did the nanostructuring and surface roughness. This was coupled with a decrease in film thickness. Incubation of the nanostructured thin-films in bacterial broths with E. coli and S. aureus showed that as the surface roughness increased the antimicrobial activity was enhanced – both in solution and for bacteria adhered to the thin-films. Inductively coupled plasma mass spectrometry was used to measure silver leaching from the thin-films and showed a negligible loss for all films, with corresponding low-levels of antimicrobial activity. Further indicating the enhancing effect of nanostructuring as an antimicrobial. All thin-films showed biological fouling after prolonged exposure to the bacterial solutions, which reduced antimicrobial activity. Cleaning the films with IPA showed that the films could be regenerated but with some loss of antimicrobial activity. The mechanism of thin-film antimicrobial activity is at this time unknown but it is speculated that nanostructuring is capable of penetrating the cell envelopes of bacteria, which enhances the antimicrobial activity of silver

An antiviral disinfectant research and development process model for small to medium enterprises based within the United Kingdom

Viral infections have produced commercial drivers to develop products to treat and reduce viral outbreaks and infections. Antiviral disinfectants have found particular favour in limiting new infections. The nature of viruses has however necessitated a continued stream of products successfully moving through the research and development (R&D) stage into commercial usage. With high product failure rates in R&D, and difficulties for executive and R&D managers to communicate effectively in the R&D stage, there was a perceived need from within the sector to further elucidate antiviral disinfectant R&D. Prior research had shown that the R&D stage is technically sophisticated with a requirement for management to engage in the technical, scientific and business aspects. This can be challenging for management decision-making, as many aspects of R&D, have different levels of knowledge required as well as language used. The use of models has received much attention in simplifying the R&D stage, but with little attention paid to creating shared meaning between different managers. In this study, executive and R&D managers from antiviral disinfectant UK based R&D SMEs were examined, using semi-structured case study interviews within a phenomenological paradigm. Explicitation was used to draw out meaning from respondent interviews, which showed that executive and R&D managers were from business and scientific backgrounds respectively. This resulted in difficulties in communication about R&D between manager types, which added to the opacity of R&D. It was noted that executive managers had greater knowledge of wider organisational aims for R&D, but little knowledge about what was carried out in the R&D stage. Conversely, R&D managers had greater knowledge about the scientific testing carried out in R&D, but little understanding of the business drivers of R&D. Using interview information, an alpha and beta model were constructed that showed a linear path through R&D, based predominantly on technical stages. An expanded view of the model was utilised to aid in R&D and executive management sense made of the R&D. This model contributed to the knowledge base through shared and warranted knowledge between R&D and executive managers as well as expanded model views of each of the R&D process stages. Both of these factors are novel and have created new academic knowledge as well as this model currently being used by three respondent companies

Easing the Transition from Inspiration to Implementation: A Rapid Prototyping Platform for Wireless Medium Access Control Protocols

Packet broadcast networks are in widespread use in modern wireless communication systems. Medium access control is a key functionality within such technologies. A substantial research effort has been and continues to be invested into the study of existing protocols and the development of new and specialised ones. Academic researchers are restricted in their studies by an absence of suitable wireless MAC protocol development methods. This thesis describes an environment which allows rapid prototyping and evaluation of wireless medium access control protocols. The proposed design flow allows specification of the protocol using the specification and description language (SDL) formal description technique. A tool is presented to convert the SDL protocol description into a C++ model suitable for integration into both simulation and implementation environments. Simulations at various levels of abstraction are shown to be relevant at different stages of protocol design. Environments based on the Cinderella SDL simulator and the ns-2 network simulator have been developed which allow early functional verification, along with detailed and accurate performance analysis of protocols under development. A hardware platform is presented which allows implementation of protocols with flexibility in the hardware/software trade-off. Measurement facilities are integral to the hardware framework, and provide a means for accurate real-world feedback on protocol performance