Contamination Estimation via Convex Relaxations

Identifying anomalies and contamination in datasets is important in a wide variety of settings. In this paper, we describe a new technique for estimating contamination in large, discrete valued datasets. Our approach considers the normal condition of the data to be specified by a model consisting of a set of distributions. Our key contribution is in our approach to contamination estimation. Specifically, we develop a technique that identifies the minimum number of data points that must be discarded (i.e., the level of contamination) from an empirical data set in order to match the model to within a specified goodness-of-fit, controlled by a p-value. Appealing to results from large deviations theory, we show a lower bound on the level of contamination is obtained by solving a series of convex programs. Theoretical results guarantee the bound converges at a rate of $O(\sqrt{\log(p)/p})$, where p is the size of the empirical data set.Comment: To appear, ISIT 201

Food Habits of Snakes in an East Texas State Fish Hatchery

A study was conducted from 1 August 1969 to 1 August 1970 in the Jasper State Fish Hatchery near Jasper, Texas to determine the amount of predation by snakes on fish being propagated. The hatchery consisted of 63 earthen ponds. A total of 373 snakes were captured. Results of stomach contents analyses of the 206 snakes containing food were calculated in per cent frequency of occurrence and per cent volume. Frogs, primarily Ranidae, were found to be the major food item. Fish were taken far less frequently, representing only 13.3 % (by volume) and 15.5 % frequency of occurrence. The two predominant snake species were Natrix fasciata confluens and Agkistrodon piscivorous leucostorna. From this study it was concluded that snakes did not pose a major fish predation problem. Thus, snake control in this hatchery is not necessary at the present time

The Sample Complexity of Search over Multiple Populations

This paper studies the sample complexity of searching over multiple populations. We consider a large number of populations, each corresponding to either distribution P0 or P1. The goal of the search problem studied here is to find one population corresponding to distribution P1 with as few samples as possible. The main contribution is to quantify the number of samples needed to correctly find one such population. We consider two general approaches: non-adaptive sampling methods, which sample each population a predetermined number of times until a population following P1 is found, and adaptive sampling methods, which employ sequential sampling schemes for each population. We first derive a lower bound on the number of samples required by any sampling scheme. We then consider an adaptive procedure consisting of a series of sequential probability ratio tests, and show it comes within a constant factor of the lower bound. We give explicit expressions for this constant when samples of the populations follow Gaussian and Bernoulli distributions. An alternative adaptive scheme is discussed which does not require full knowledge of P1, and comes within a constant factor of the optimal scheme. For comparison, a lower bound on the sampling requirements of any non-adaptive scheme is presented.Comment: To appear, IEEE Transactions on Information Theor

MERLOT: a faculty-focused website of educational resources

Journal ArticleThe Multimedia Educational Resource for Learning and Online Teaching (MERLOT) is a community of academic institutions, professional discipline organizations, and individual people building a collection of Web-based teaching and learning resources where faculty can easily find peer-reviewed materials for use in their classes. The MERLOT project is currently supported by 23 systems and institutions of higher education and by the National Science Foundation. MERLOT is developing collections of learning materials from many academic disciplines, including psychology

Recommendations for KYTC’s Railway/Highway At-Grade Crossing Surface Management Practices

An ideal Railway/Highway At-Grade Crossing Management program involves selecting costeffective practices when designing new crossings and rehabilitating existing crossings. This report outlines two strategies to enhance KYTC’s existing program. First, it describes a process that uses decision-option diagrams to optimize the assessment and implementation of engineering solutions in order to restore desired smoothness, minimize settlement in the postconstruction phase, and foster acceptable long-term performance of crossings following their rehabilitation. Decision-option diagrams rely on assessments that are site-specific and based on historical performance, the present observed performance and condition, and the measureable parameters specific to particular crossings. To supplement this process, the second strategy that this report proposes is the establishment of an effective managerial structure at KYTC that streamlines decision-making to ensure that the selected design is properly applied and implemented. Taken together, these proposals will significantly improve the state’s ability to systematically and cost-effectively repair deteriorated crossings

Railway/Highway At-Grade Crossing Surface Rehabilitation Manual: Recommendations and Guides

This Railway/Highway At-Grade Crossing Surface Rehabilitation Manual offers guidance to engineers and project planners for designing, constructing, and managing railway/highway crossing rehabilitation projects. The manual includes information on pre-project administration, project execution, and post-project management and oversight. Suggestions are provided for determining the most cost-effective rehabilitation procedure, techniques to insure the appropriate installation procedures are followed onsite, and instructions for post-project administration and inspection procedures. The primary goal of this manual is to aid with the implementation of a crossing rehabilitation program; all of its guidance underscores the importance of achieving costeffective solutions through the use of best practices to build crossings that are safe and smooth, perform at a high level, and have a long service life, which benefits railroads as well the driving public