Three-dimensional Radial Visualization of High-dimensional Datasets with Mixed Features

We develop methodology for 3D radial visualization (RadViz) of high-dimensional datasets. Our display engine is called RadViz3D and extends the classical 2D RadViz that visualizes multivariate data in the 2D plane by mapping every record to a point inside the unit circle. We show that distributing anchor points at least approximately uniformly on the 3D unit sphere provides a better visualization with minimal artificial visual correlation for data with uncorrelated variables. Our RadViz3D methodology therefore places equi-spaced anchor points, one for every feature, exactly for the five Platonic solids, and approximately via a Fibonacci grid for the other cases. Our Max-Ratio Projection (MRP) method then utilizes the group information in high dimensions to provide distinctive lower-dimensional projections that are then displayed using Radviz3D. Our methodology is extended to datasets with discrete and continuous features where a Gaussianized distributional transform is used in conjunction with copula models before applying MRP and visualizing the result using RadViz3D. A R package radviz3d implementing our complete methodology is available.Comment: 12 pages, 10 figures, 1 tabl

Market Strategy of Chinese Educational Agencies

present at Midwest Economics Conference 2013With more and more Chinese students coming to study in the US, more and more educational agencies opened up in China. Those agencies help students in China applying for US colleges. This new rising market is attractive and growing rapidly. Not only in China, there are many educational agencies like these established in Korea, Japan and India. The regulation for the market seems to be weak in China. There is no standard price for the market; so many agencies can charge a high price. This study focuses on the equilibrium price of the educational agencies markets in China and the factors that affect the price they charge. Prices of more than 70 agencies form China had been collected. The study compares the price charged by agencies of different region, different size and other factors. Quantitative results show that the supply side of the market (agencies) could have more market power than the demand side of the market (students). The supply side of the market has more information on the application process than the demand side of the market. There is also a big regional distinction between the big cities and small cities as well as north and south China. The ranking of a university plays the most important role in determining the price difference within an agency. The study aims to find a solution to regulate the educational market in China.Undergraduate Research Awards summer 2012No embargoAcademic Major: Economic

An Optimization Analysis of the Subject Directory System on the Medlineplus Portal - An Investigation of Mental Health, Children, Teenagers, and Older Adults Related Health Topics

The Internet is a common means for people to search for health information. The subject directory of MedlinePlus offers Internet searchers a browsing environment so that those seekers could start from a broad term and refine their search terms to meet their real information needs, thus resulting in a better information search. For those novice users who are not familiar with relevant domain knowledge, MedlinePlus’s directory can be of great assistance and enable the portal to adopt to a more general population. Such a subject directory system and its involved health topics in the MedlinePlus portal formed a network where a specific research methodology, social network analysis, is applicable. In this study, four health topic groups – mental health, children, teenagers, and older adults - were selected as the focus for the investigation toward the subject directory on the MedlinePlus portal. This study applied social network analysis to explore the health topic directories and connection patterns among the health topics that comprised the subject directory of the MedlinePlus portal, and identified the influential topics (i.e., those health topics which play more important roles than others in connecting different topics) among the topic networks. As a result, different recommendations were made toward mental health, children, teenagers, and older adults related health topics, respectively. New optimized structural networks were suggested to be built for each of the four health topic subcategories according to the similarity values calculated through the cosine similarity measure in terms of the textual information contained in health topics’ Web pages, as well as the key nodes identified in the networks of health topics. Evaluations were later conducted to compare the original and optimized structural networks of the four health topic groups regarding their topics’ new similarity values. Newly identified influential health topics were verified to have improved the overall semantic connections among the whole networks. Last but not least, the recommendation results were evaluated by two health field experts and the evaluation outcomes proved that the recommendations suggested in this study were consistent with the opinions generated by health professionals. The findings of this research will provide suggestions to optimize and enhance the current navigation guidance system in MedlinePlus, improve the information searching effectiveness among the portal users, offer insights to public health portal creators, and support other researchers focusing on subject directory systems

Nitrogen Cycling in the Lower Chesapeake Bay and Mid- and South Atlantic Bight

Nitrogen (N) is central to marine primary production; its availability often limits the capacity and rates of primary productivity in most of the world’s oceans. Contrastingly, estuaries frequently receive anthropogenic N loading, oftentimes resulting in eutrophication, harmful algal blooms (HABs), and substantially degraded water quality. Nutrient variability in both estuaries and oceanic regimes results from meteorological forcing and physical processes, including wind-induced, tidal, and mesoscale mixing and upwelling. In this dissertation, a comprehensive investigation of N variability and cycling and its links to physical-biogeochemical processes was conducted using time-series monitoring approaches, flux estimations, satellite imaging, biogeochemical measurements, and molecular analyses. The study focused on three contrasting regions along the east coast of the United States. The study regions involved the lower Chesapeake Bay where the dinoflagellate, Margalefidinium polykrikoides, develops harmful blooms almost every year, to the coastal waters of Atlantic and Gulf Stream off Cape Hatteras, and the New England shelf break (NES) frontal zone dominated by diatoms and cyanobacteria. Cyanate, a recently identified N cycle intermediate, was present in nanomolar concentrations in the lower Chesapeake Bay, and its variability was regulated by algal production, degradation, and sediment resuspension. Water and nutrient fluxes were strongly driven by tidal cycles, and wind speed and direction. In the coastal ocean off Cape Hatteras, total N uptake rates by phytoplankton were significantly higher in the Mid-Atlantic Bight than the South Atlantic Bight (SAB), likely due to co-limitation by phosphorus in the SAB. Among six N resources tested, nitrate and urea comprised \u3e60% of the total N uptake. The NES front acted as an ecological boundary with more nitrifiers in the diatom hotspots of the Slope Sea than on the shelf, suggesting higher levels of N recycling than on the shelf. Several slope stations had unexpectedly high phytoplankton biomass due to the supply of deep-water nutrients via isopycnal lifting induced by Gulf Stream intrusion, which may have stimulated both ammonium regeneration and nitrification. Consequently, N cycling is strongly affected by a combination of physical and biological processes that create distinct oceanographic zones in western Atlantic Ocean

Eulerian walk and DNA sequence assembly

Children like jigsaw puzzles, and the way to assemble the puzzle is by putting together pieces that match, one by one, till the puzzle is complete. DNA sequence assembly could be thought of as something similar: when a strand of DNA is passed into a particular “sequencing machine”, it gives a large number of short reads of the DNA sequence. This type of technology is called shotgun sequencing. These reads form the jigsaw pieces in the puzzle and one must put together these pieces in an intelligent way to obtain the original sequence. There is, however, a catch here; apriori, we do not know what the original sequence or the“jigsaw big picture” looks like. Yet, the philosophy remains the same: to connect pieces or reads which are similar and hope that the “big picture” is reconstructed

Model Driven Combat Effectiveness Simulation Systems Engineering

Model-driven engineering has become popular in the combat effectiveness simulation systems engineering during these last years. It allows to systematically develop a simulation model in a composable way. However, implementing a conceptual model is really a complex and costly job if this is not guided under a well-established framework. Hence this study attempts to explore methodologies for engineering the development of simulation models. For this purpose, we define an ontological metamodelling framework. This framework starts with ontology-aware system conceptual descriptions, and then refines and transforms them toward system models until they reach final executable implementations. As a proof of concept, we identify a set of ontology-aware modelling frameworks in combat systems specification, then an underwater targets search scenario is presented as a motivating example for running simulations and results can be used as a reference for decision-making behaviors