Week One in the Galapagos

Postcard from Michael McGrath, during the Linfield College Semester Abroad Program at the Galápagos Academic Institute of the Arts and Sciences in the Galápagos Islands, Ecuado

Markov random field image modelling

Includes bibliographical references.This work investigated some of the consequences of using a priori information in image processing using computer tomography (CT) as an example. Prior information is information about the solution that is known apart from measurement data. This information can be represented as a probability distribution. In order to define a probability density distribution in high dimensional problems like those found in image processing it becomes necessary to adopt some form of parametric model for the distribution. Markov random fields (MRFs) provide just such a vehicle for modelling the a priori distribution of labels found in images. In particular, this work investigated the suitability of MRF models for modelling a priori information about the distribution of attenuation coefficients found in CT scans

Spatial Distribution of Planktonic Copepoda and Cladocera in Red Rock Reservoir, Iowa, Summer, 1972

34 leaves.The problem. The measurement of spatial distribution of Copepoda and Cladocera in Red Rock Reservoir, Iowa, summer, 1972, was undertaken. Water temperature, Secchi disk, and total water depth readings were also measured. Procedure. Volumetric samples of free-swimming zooplankton were collected at weekly intervals from June 6 to September 8, 1972. Collections were made at three stations on each of four transects representing different areas of the reservoir. Samples were obtained from one meter intervals from the surface to three meters. Findings. Sater temperature varied from a low of 18.5 C to a high of 30.0 C. Secchi disk readings ranged from 6 to 70 cm. Maximum readings were obtained near the dam and decreased towards the headwaters. Retention time varied from 3.9 to 55.6 days with a study mean of 10.7 days. A gradual increase in zooplankton numbers was noted from June 16 until a high was reached on July 5 (356 organisms per liter). The numbers then rapidly decreased until a low was reached on August 15 (0 organisms per liter). The dam transect always had the highest numbers of organisms with headwater transects having lower numbers of organisms. Eight species of zooplankton were identified during the study. Conclusions. Highest zooplankton populations occurred near the dam with smaller numbers present up reservoir. Numbers of zooplankton per liter and retention times were lower than during a 1970 study. Retention time was the main controlling factor on zooplankton development. No correlations were found between zooplankton numbers and temperature, light penetration, and depth. Recommendations. More station sites and more frequent sampling could enable the study of horizontal distribution of zooplankton. Monitoring reservoir inflow and outflow would enable the determination of population development within the reservoir. The interaction of zooplankton with phytoplankton and macrophytes should be investigated

Student experiences of virtual reality - a case study in learning special relativity

We present a study of student learning through the use of virtual reality. A software package is used to introduce concepts of special relativity to students in a game-like environment where users experience the effects of travelling at near light speeds. From this new perspective, space and time are significantly different to that experienced in everyday life. The study explores how students have worked with this environment and how these students have used this experience in their study of special relativity. A mixed method approach has been taken to evaluate the outcomes of separate implementations of the package at two universities. Students found the simulation to be a positive learning experience and described the subject area as being less abstract after its use. Also, students were more capable of correctly answering concept questions relating to special relativity, and a small but measurable improvement was observed in the final exam

Energetics, Information, and self-regulation

All living systems need to obtain energy, learn about their environments, and maintain their internal state. The complexity of these processes varies enormously across different types of life, from the simple chemotactic foraging of \textit{E. coli} to the complex behaviours of mammals. In spite of this complexity, there may be general statements we can make about the processes of learning and homeostasis that are valid across the range of complexity we see in nature and even beyond. This thesis contains a series of explorations on these themes, linked by the central importance of energetic considerations. In Part I we outline a class of stochastic models for understanding homeostatic behaviour and alleviating modelling challenges presented by conventional ethological tools. We apply this model class to understand feeding behaviour in rodents. In doing so we find that anorectic agents have different behavioural profiles compared to natural satiation, and uncover how information from the gut is integrated into feeding strategies that differ between night and day. Finally, we perform \textit{in silico} experiments and find behavioural interventions of comparable effectiveness to current anorectic agents. In Part II we use stochastic thermodynamics to investigate the energetic constraints on learning and using a model of the world. We define an analytically-tractable system in which mutual information and work can be interchanged, and investigate the dynamics, efficiency, and regimes of operation of this system. We discover a regime in which information can act as a catalyst, allowing for increased work extraction. Next we define and investigate a thermodynamic system that performs online supervised learning. We find that learning in this system is inherently nonequilibrium and investigate the energetics of supervised learning.Open Acces

Product strategy for high technology companies

Companies looking to make in today’s crowded hightech battlefield need two primary element : a distinctive product and a powelful product strategy. Without both, they simply won’t survive. Product Strategy for High Technology Companies, 2nd Edition. Is today’s only book on product strategy written speciifically for hig-tech companies. Updated and revise to encompass everything from changing product strategies to Web-Based technologies, this forward thinking book provides page on market-tested strategis and techniques that include : • An in-depth examination of the market proven Core Strategies Vision (CSV) and Market Platform Plan (MPP) frameworks. • Case studies examining 14 unique differetiation strategies-what worked, what didn’t, and why • More than 250 examples of product strategy in action, from the success of Microsoft to the equally stunning-at the time-failure of Osborne The opportunities in today’s wide-open technology marketplace are unparalleled in history. Benchmark yourself against the hightech leaders-and discover techniques to carve out your own area of expertise and success-with Product Strategy for Hig Technology Companies