Digital Commons Network^™

Refactoring Tools: Fitness For Purpose, Emerson Murphy-Hill, Andrew P. Black

Computer Science Faculty Publications and Presentations

Refactoring tools can improve the speed and accuracy with which we create and maintain software -- but only if they are used. In practice, tools are not used as much as they could be: this seems to be because sometimes they do not align with the refactoring tactic preferred by the majority of programmers, a tactic we call floss refactoring. We propose five principles that characterize successful floss refactoring tools -- principles that can help programmers to choose the most appropriate refactoring tools and also help toolsmiths to design tools that fit the programmer's purpose.

Scalable Concurrent Hash Tables Via Relativistic Programming, Josh Triplett

Computer Science Faculty Publications and Presentations

Existing approaches to concurrent programming often fail to account for synchronization costs on modern shared-memory multipro- cessor architectures. A new approach to concurrent programming, known as relativistic programming, can reduce or in some cases eliminate synchronization overhead on such architectures. This approach avoids the costs of inter-processor communication and memory access by permitting processors to operate from a relativistic view of memory provided by their own caches, rather than from an absolute reference frame of memory as seen by all processors. This research shows how relativistic programming techniques can provide the perceived advantages of optimistic synchronization without the useless parallelism …

Reconstructing Images As Piecewise Smooth Functions, Ralf Juengling

Computer Science Faculty Publications and Presentations

Leclerc’s approach to image reconstruction consists of finding the shortest description of the data (an image) as a model (reconstruction) plus noise [5]. The approach poses two design problems: 1. Define an appropriate description language for image models and noise, 2. Derive an objective function and conceive an optimization algorithm that finds good local minima. Leclerc proposed to model images as piecewise low order polynomials and to describe models in terms of region boundaries (discontinuity set) and polynomial coefficients.

In this report I describe Leclerc’s methodology, and, adopting his image model and description language, derive an objective function within this …

Predicting Within-Source Agreement In Multisource Feedback Ratings: An Examination Of Characteristics Of The Rater Group And The Focal Manager, Christine Schrader Fernandez

Dissertations, Theses, and Capstone Projects

Multisource feedback (MSF) involves gathering information about a manager's effectiveness from his or her boss, peers, and subordinates. Researchers typically average MSF ratings within rating sources (e.g., peers or subordinates), which assumes that agreement within rating sources is relatively high. However, there is little prior MSF research that has addressed the issue of within-source agreement, and the extant studies have often used inappropriate statistical techniques such as reliability indices. Moreover, this research often focuses on assessing the mean level of agreement or reliability within rating sources but has ignored the variability surrounding these indices. The purpose of the present study …

Correction To "Stochastic Comparisons Of Parallel Systems When Components Have Proportional Hazard Rates", Subhash C. Kochar, Maochao Xu

Mathematics and Statistics Faculty Publications and Presentations

In the article "Stochastic comparisons of parallel systems when component have proportional hazard rates" we found a gap in the middle of the proof of Theorem 3.2. Therefore, we do not know whether Theorem 3.2 is true for the reverse hazard rate order. However, we could prove the following weaker result for the stochastic order.

Multigrid Convergence For Second Order Elliptic Problems With Smooth Complex Coefficients, Jay Gopalakrishnan, Joseph E. Pasciak

Mathematics and Statistics Faculty Publications and Presentations

The finite element method when applied to a second order partial differential equation in divergence form can generate operators that are neither Hermitian nor definite when the coefficient function is complex valued. For such problems, under a uniqueness assumption, we prove the continuous dependence of the exact solution and its finite element approximations on data provided that the coefficients are smooth and uniformly bounded away from zero. Then we show that a multigrid algorithm converges once the coarse mesh size is smaller than some fixed number, providing an efficient solver for computing discrete approximations. Numerical experiments, while confirming the theory, …

Asymptotic And Numerical Techniques For Resonances Of Thin Photonic Structures, Jay Gopalakrishnan, Shari Moskow, Fadil Santosa

Mathematics and Statistics Faculty Publications and Presentations

We consider the problem of calculating resonance frequencies and radiative losses of an optical resonator. The optical resonator is in the form of a thin membrane with variable dielectric properties. This work provides two very different approaches for doing such calculations. The first is an asymptotic method which exploits the small thickness and high index of the membrane. We derive a limiting resonance problem as the thickness goes to zero, and for the case of a simple resonance, find a first order correction. The limiting problem and the correction are in one less space dimension, which can make the approach …

Surface Temperature Mapping Of The University Of Northern Iowa Campus Using High Resolution Thermal Infrared Aerial Imagery, Alexander Savelyev

Dissertations and Theses @ UNI

The goal of this study was to produce and analyze a heat loss map of the University of the Northern Iowa campus using thermal infrared remote sensing data. Aerial data with the spatial resolution of 0.29m and radiometric resolution of 14 bit was collected. A model for the pixel to radiance and temperature conversion was developed with its parameters estimated with an R² of 0.78. Temperature imagery was shown to be consistent over the time of the survey and accurate to within 12°C. The temperature map then was used to assess the conditions of the rooftops and steam pipelines …

Reframed Teacher Leadership: A Narrative Inquiry, Cynthia L. Kenyon

Dissertations and Theses @ UNI

Teacher leadership has been in schools from the time teachers rang the school bells. Three waves of teacher leadership have been examined. The first wave focused on formal managerial positions such as department chairs, the second wave focused on curriculum and staff development, and the third wave focused on daily acts of collaboration to solve problems and provide professional development activities for staffs. This study explored the third wave practice of teacher leaders in a qualitative study focusing on the narratives of 11 teacher leaders.

A narrative of lives format was used to study leadership experiences. A pilot study was …

Does Content Knowledge Matter In Scoring Teacher Work Samples?: A Study Of Rater Differences, Yana A. Cornish

Dissertations and Theses @ UNI

The study examines the role of rater characteristics in the assessment of teacher practice as presented in Renaissance Teacher Work Samples (RTWS). The study analyzed ratings of 10 teacher work samples submitted by teacher candidates at the University of Northern Iowa between Fall 2000 and Spring 2004. These teacher work samples, created in the area of Spanish language learning at 7-11 grade levels, were analyzed to determine the impact of content expertise, amount of teaching experience, and previous RTWS rating experience on reviewer's ratings. Three study questions form the foundation for the investigation:

(1) Is there a significant difference between …

The Architecture Of Charities’ Commercial Activities - Structural Reactions: Basic Structures, Stephen Schwarz

Faculty Scholarship

No abstract provided.

A Case Study Of A Rural Iowa School Preparing To Meet New State Guidelines For School Libraries [Dissertation], Karla Steege Krueger

Dissertations and Theses @ UNI

The national school library guidelines place the greatest emphasis upon the teaching and learning component of school library programs led by professional school librarians. Despite findings linking school library programming, including instruction by professional school librarians, to increased student achievement on standardized tests and improved content learning through student inquiry using library resources, the importance of the instructional role of the school librarian remains largely unrecognized by administrators and teachers.

A qualitative case study of one rural Iowa elementary school provided insight into the issue of small schools without library programs as they are preparing to meet the Iowa reinstatement …

Synthesis And Characterization Of New Luminescent Late Transition Metal Complexes Containing The Tridentate 1,3-Di(N-Pyrazolyl)-4,6-Dimethyl Benzene Ligand, Brian Christopher Gruver

Dissertations and Theses @ UNI

The tridentate 1,3-di(N-pyrazolyl) benzene L 1 was synthesized from dibromobenzene and pyrazole. When reacted with K2PtC14 and IrCl3 the asymmetric complexes (µ-Cl)2(PtL1 )2 and (µ-Cl)2[lr L12]2 were obtained. The tridentate l ,3- dimethyl-4,6-(di-N-pyrazolyl) benzene ligand L2 , was synthesized from di-bromo-mxylene and pyrazole. The ligand was reacted with K2PtC14 to give L2 PtCl. Further reaction with phenylacetylene led to the air sensitive acetylide complex L2 PtC=C(C6H5). L2 PtCl could also be reacted with AgOTf in acetonitrile to give [L2 PtN=CCH3] OTf. Reaction with other late transition metals led to the di-chloro bridged iridium dimer (µ-Cl)2[L 2IrCl]2 and the square planar …