Digital Commons Network^™

On The Role Of Shape Prototypes In Hierarchical Models Of Vision, Michael David Thomure, Melanie Mitchell, Garrett T. Kenyon

Computer Science Faculty Publications and Presentations

We investigate the role of learned shape-prototypes in an influential family of hierarchical neural-network models of vision. Central to these networks’ design is a dictionary of learned shapes, which are meant to respond to discriminative visual patterns in the input. While higher-level features based on such learned prototypes have been cited as key for viewpointinvariant object-recognition in these models [1], [2], we show that high performance on invariant object-recognition tasks can be obtained by using a simple set of unlearned, “shape-free” features. This behavior is robust to the size of the network. These results call into question the roles of …

The Problem Of Semantics In The Metadata Mess, Veronika Margaret Megler, David Maier

Computer Science Faculty Publications and Presentations

This presentation addresses problems related to the volume of available scientific data, and its accessibility or inaccessibility to researchers who seek it. Topics addressed include metadata and reducing semantic diversity, especially as they refer to geospatial and other architectures

Taming The Metadata Mess, Veronika Margaret Megler

Computer Science Faculty Publications and Presentations

The rapid growth of scientific data shows no sign of abating. This growth has led to a new problem: with so much scientific data at hand, stored in thousands of datasets, how can scientists find the datasets most relevant to their research interests? We have addressed this problem by adapting Information Retrieval techniques, developed for searching text documents, into the world of (primarily numeric) scientific data. We propose an approach that uses a blend of automated and “semi-curated” methods to extract metadata from large archives of scientific data, then evaluates ranked searches over this metadata. We describe a challenge identified …

Interpreting Individual Classifications Of Hierarchical Networks, Will Landecker, Michael David Thomure, Luis M.A. Bettencourt, Melanie Mitchell, Garrett T. Kenyon, Steven P. Brumby

Computer Science Faculty Publications and Presentations

Hierarchical networks are known to achieve high classification accuracy on difficult machine-learning tasks. For many applications, a clear explanation of why the data was classified a certain way is just as important as the classification itself. However, the complexity of hierarchical networks makes them ill-suited for existing explanation methods. We propose a new method, contribution propagation, that gives per-instance explanations of a trained network's classifications. We give theoretical foundations for the proposed method, and evaluate its correctness empirically. Finally, we use the resulting explanations to reveal unexpected behavior of networks that achieve high accuracy on visual object-recognition tasks using well-known …

Nonnegativity Of Exact And Numerical Solutions Of Some Chemotactic Models, Patrick De Leenheer, Jay Gopalakrishnan, Erica Zuhr

Mathematics and Statistics Faculty Publications and Presentations

We investigate nonnegativity of exact and numerical solutions to a generalized Keller–Segel model. This model includes the so-called “minimal” Keller–Segel model, but can cover more general chemistry. We use maximum principles and invariant sets to prove that all components of the solution of the generalized model are nonnegative. We then derive numerical methods, using finite element techniques, for the generalized Keller–Segel model. Adapting the ideas in our proof of nonnegativity of exact solutions to the discrete setting, we are able to show nonnegativity of discrete solutions from the numerical methods under certain standard assumptions. One of the numerical methods is …

Compositional Diversity In The Atmospheres Of Hot Neptunes, With Application To Gj 436b, J. I. Moses, M. R. Line, Channon Visscher, M. R. Richardson, N. Nettleman, J. J. Fortney, T. S. Barman, K. B. Stevenson, N. Madhusudhan

Faculty Work Comprehensive List

Neptune-sized extrasolar planets that orbit relatively close to their host stars—often called "hot Neptunes"—are common within the known population of exoplanets and planetary candidates. Similar to our own Uranus and Neptune, inefficient accretion of nebular gas is expected produce hot Neptunes whose masses are dominated by elements heavier than hydrogen and helium. At high atmospheric metallicities of 10-10,000 times solar, hot Neptunes will exhibit an interesting continuum of atmospheric compositions, ranging from more Neptune-like, H₂-dominated atmospheres to more Venus-like, CO₂-dominated atmospheres. We explore the predicted equilibrium and disequilibrium chemistry of generic hot Neptunes and find that …

Chemistry Of Impact-Generated Silicate Melt-Vapor Debris Disks, Channon Visscher, Bruce Fegley Jr.

Faculty Work Comprehensive List

In the giant impact theory for lunar origin, the Moon forms from material ejected by the impact into an Earth-orbiting disk. Here we report the initial results from a silicate melt-vapor equilibrium chemistry model for such impact-generated planetary debris disks. In order to simulate the chemical behavior of a two-phase (melt+vapor) disk, we calculate the temperature-dependent pressure and chemical composition of vapor in equilibrium with molten silicate from 2000 to 4000 K. We consider the elements O, Na, K, Fe, Si, Mg, Ca, Al, Ti, and Zn for a range of bulk silicate compositions (Earth, Moon, Mars, eucrite parent body, …

Comment On "Density And Physical Current Density Functional Theory", Xiao-Yin Pan, Viraht Sahni

Publications and Research

In this letter to the editor, the authors comment on an earlier article they had published, "Density and Physical Current Density Functional Theory" (Pan, X.-Y. and Sahni, V. (2010), Density and physical current density functional theory. Int. J. Quantum Chem., 110: 2833–2843. doi: 10.1002/qua.22862).

School Wide Positive Behavioral And Intervention Supports : The Effectiveness Of Tier 1 Strategies, Gregory James Halsor

Dissertations and Theses @ UNI

This literature review critically examines the effectiveness of Tier 1 Positive Behavioral and Intervention Supports (SWPBIS). Managing problem behavior in the school setting has been a major focus of educators, with the goal of lowering classroom disruptions and increasing the effectiveness of learning.

Over the years, school wide behavior management programs have not been consistent or widespread leading educators to identify disruptive behavior as a primary concern in their classrooms. SWPBIS emphasizes the integration of measurable outcomes, data-based decision making, and evidence based interventions. Research on the implementation of SWPBIS in schools has displayed positive effects related to decreasing the …

Comparing Second Grade Students' Creative And Content Knowledge Performance On Figural Transformation Activities Introduced In A Standard Or Enhanced Manner With Nutrition Content Knowledge Taught Through Factual Or Fantasy Reading, Angela Naomi Webb

Dissertations and Theses @ UNI

Creativity and problem solving are skills students need for success in the 21st century. With the increasing pressures of achieving higher student scores in emphasized content areas, teachers' instruction in science, social studies, music and art has been reduced to provide additional time for teaching reading and mathematics.These lost instructional areas often allowed students to express themselves creatively. Therefore, educators need to find a way to incorporate creativity into content areas like reading and mathematics.

This 16 week repeated measures study examined second grade students' academic and creative performance on figural transformation drawings during an extended reading-science-creativity integrated unit. A …

Comparing Sixth Grade Students' Creativity In Word Play To Spatial Construction With Integrated Academic Content Eliciting A Distal Or Proximal Perspective, Ksenia S. Zhbanova

Dissertations and Theses @ UNI

Pressing global problems require solutions from innovative ideas that depend upon educating a new generation to think creatively. The current study aimed at assisting 24 sixth grade students in a summer program develop their creativity skills in two different areas while integrating academic content. Student performance was examined for transfer of skills across domains and for support of Construal Level Theory, which holds that addressing topics distant in space, time, probability or experience leads to abstract thought supporting greater creativity.

The study was a counterbalanced, repeated measures, two-experimental condition study with students divided into two groups of 12 each. In …

Designing Elementary Engineering Education From The Perspective Of The Child, Beth Dykstra Van Meeteren

Dissertations and Theses @ UNI

Many concerned leaders of industry and government believe the ability to sustain our quality of life and address the grand challenges of our times is contingent upon the successful engagement of our younger children in science, technology, engineering, and mathematics (STEM). What STEM curricula, specifically engineering curricula, should address, how the curriculum should be delivered, and how the children construct an understanding of engineering are still unanswered questions. Engineering curriculum is beginning to emerge for elementary students, but does more to teach children about engineering than allowing them to develop engineering habits of mind.

This qualitative study used constant comparative …

Factors That Influence Superintendents In Iowa To Implement A One-To-One Computer Initiative, Gerald Eugene Schnabel

Dissertations and Theses @ UNI

The purpose of this study is to identify factors that influence superintendents in Iowa to implement a one-to-one computer initiative. An in-depth, phenomenological based interview method was used. Two interviews were conducted with each of the five superintendents in the study. The superintendent responses were then organized using the Saskatchewan Educational Indicators, which are context, process and outcome indicators. The major questions addressed in the study were: 1. What factors influenced the decision to implement a one-to-one computer initiative? 2. What are the results of implementing a one-to-one computer initiative? 3. What decision-making process do superintendents in Iowa use when …

An Analysis Of The Effect Of A 21st-Century-Designed Middle School On Student Achievement, Gary David Schwartz

Dissertations and Theses @ UNI

Considering the billions of dollars invested in school buildings and the accountability for improving student achievement, there has been the lingering question about how the physical learning environment impacts student achievement. This study explored the impact of a new 21st-century-designed middle school facility on student academic achievement in mathematics and science. This case study used a mixed methods approach to examine the student achievement of 158 middle school students and the perceptions from 13 teachers and two administrators about the impact of the new facility on teaching and student learning. The purpose of this study was to analyze the effect …

Leading Through Change: A Study Of The Role Of Central Office Leadership In The Process Of Secondary Change, Dirk A. Halupnik

Dissertations and Theses @ UNI

The purpose of this study was to more fully understand the actions of district level leaders in a major change effort and their effects on the change process. Furthermore this study aimed to provide additional information about the factors that school district central office administrators confront when making the decision to add another high school and the actions taken by these administrators to lead the district through this process so that other school districts and leaders may learn from this. The methodology for this study was a qualitative case study approach in which central office leaders in a district that …

Understanding The Critical Role Of A Wetland In Maintaining The Ecosystem: A Case Study, Sushil Tuladhar

Dissertations and Theses @ UNI

Beaver Valley Wetland in north-east Iowa was studied to determine its functionality in filtering incoming contaminants from the surrounding agricultural fields. The study was conducted from May through November of 2011. Altogether 78 water samples (from 13 sites), 84 soil samples (from 14 sites), and some sediment samples were collected for chemical analysis. Heavy metals in three different soil categories, such as surface, 6” deep, and sediments were found to be at or below the acceptable concentrations, indicating no immediate concern for metal toxicity in the wetland environment. The chemical tracers that were used to study the sub-surface flow regime …

Investigating Blended Learning In The High School Science Classroom, Holly Cassandra Hinkhouse

Dissertations and Theses @ UNI

Blended learning combines the best practices of online learning with face-to-face learning and some research has shown it to have positive benefits for students at the postsecondary level. However, few studies have reported the use of blended learning in the high school setting. This study used quantitative methods to measure student attitudes and learning of science content in both a treatment and control group consisting of 9th grade Physical Science classes. Students in the treatment group experienced one semester of blended learning by using online science modules to supplement their in-class learning while the control group continued to have only …

An Investigation On How Operational Wind Turbines Are Used In Secondary Classrooms, James Smith

Dissertations and Theses @ UNI

Through a review of literature, it was found that many schools in the United States are installing operational wind turbines, but it was unclear how teachers were using them in their science, technology, engineering and mathematics (STEM) classrooms. In order to identify how these operational wind turbines were being used and to create a list of expectations for schools with operational wind turbines, this exploratory study surveyed STEM teachers from all across the United States. A stratified random sample was created using a U.S. Department of Energy database of schools with operational wind turbines. Administrators from the selected schools identified …