She Kills Monsters Prop Design

Prop design for a theoretical production of the play She Kills Monsters by Qui Nguyen. This includes the processes of analyses, research, design, drafting, budgeting, and construction

ActiveRemediation: The Search for Lead Pipes in Flint, Michigan

We detail our ongoing work in Flint, Michigan to detect pipes made of lead and other hazardous metals. After elevated levels of lead were detected in residents' drinking water, followed by an increase in blood lead levels in area children, the state and federal governments directed over $125 million to replace water service lines, the pipes connecting each home to the water system. In the absence of accurate records, and with the high cost of determining buried pipe materials, we put forth a number of predictive and procedural tools to aid in the search and removal of lead infrastructure. Alongside these statistical and machine learning approaches, we describe our interactions with government officials in recommending homes for both inspection and replacement, with a focus on the statistical model that adapts to incoming information. Finally, in light of discussions about increased spending on infrastructure development by the federal government, we explore how our approach generalizes beyond Flint to other municipalities nationwide.Comment: 10 pages, 10 figures, To appear in KDD 2018, For associated promotional video, see https://www.youtube.com/watch?v=YbIn_axYu9

How Much Risk is Acceptable?

The financial crisis has sparked proposals to reform the retirement income system. One component of such a system could be a new tier of retirement accounts. These accounts would augment declining Social Security replacement rates for low-wage workers and provide a buffer of security for middle- and upper-wage workers who, increasingly, will rely totally on 401(k) plans to supplement their Social Security. Designing such a new tier requires answering a number of questions: Mandatory or voluntary? Employee and/or employer contributions? Subsidies for low earners? Payments as lump sums or annuities? Tax favored or not? But the most fundamental question is whether the goal of the new tier is to provide a defined contribution account, where the retirement income will depend on market performance, or an account that can provide a certain percent of final earnings ñ that is, a target replacement rate...

What Does It Cost To Guarantee Returns?

The financial crisis has dramatically demonstrated how a collapse in equity prices can decimate retirement accounts. The crisis highlights the fragility of existing 401(k) plans as the only supplement to Social Security and has sparked proposals to reform the retirement income system. One component of such a system could be a new tier of retirement accounts. Given the declines in the share of earnings Social Security will replace, these accounts would bolster replacement rates for low-wage workers and increase the security of middle- and upper-wage workers who increasingly rely on their 401(k) plans to supplement Social Security. However, these new accounts could face the same risk of collapse in value seen over the past year in 401(k)s. So policymakers may find some form of guaranteed return or risk sharing desirable to prevent huge variations in outcomes. This brief explores the feasible range and the cost of the first option – guarantees...

Recent advances in understanding regulation of the Arabidopsis circadian clock by local cellular environment.

Circadian clocks have evolved to synchronise an organism's physiology with the environmental rhythms driven by the Earth's rotation on its axis. Over the past two decades, many of the genetic components of the Arabidopsis thaliana circadian oscillator have been identified. The interactions between these components have been formulized into mathematical models that describe the transcriptional translational feedback loops of the oscillator. More recently, focus has turned to the regulation and functions of the circadian clock. These studies have shown that the system dynamically responds to environmental signals and small molecules. We describe advances that have been made in discovering the cellular mechanisms by which signals regulate the circadian oscillator of Arabidopsis in the context of tissue-specific regulation

A Data Science Approach to Understanding Residential Water Contamination in Flint

When the residents of Flint learned that lead had contaminated their water system, the local government made water-testing kits available to them free of charge. The city government published the results of these tests, creating a valuable dataset that is key to understanding the causes and extent of the lead contamination event in Flint. This is the nation's largest dataset on lead in a municipal water system. In this paper, we predict the lead contamination for each household's water supply, and we study several related aspects of Flint's water troubles, many of which generalize well beyond this one city. For example, we show that elevated lead risks can be (weakly) predicted from observable home attributes. Then we explore the factors associated with elevated lead. These risk assessments were developed in part via a crowd sourced prediction challenge at the University of Michigan. To inform Flint residents of these assessments, they have been incorporated into a web and mobile application funded by \texttt{Google.org}. We also explore questions of self-selection in the residential testing program, examining which factors are linked to when and how frequently residents voluntarily sample their water.Comment: Applied Data Science track paper at KDD 2017. For associated promotional video, see https://www.youtube.com/watch?v=0g66ImaV8A

Are sketch-and-precondition least squares solvers numerically stable?

Sketch-and-precondition techniques are popular for solving large least squares (LS) problems of the form $Ax=b$ with $A\in\mathbb{R}^{m\times n}$ and $m\gg n$. This is where $A$ is ``sketched" to a smaller matrix $SA$ with $S\in\mathbb{R}^{\lceil cn\rceil\times m}$ for some constant $c>1$ before an iterative LS solver computes the solution to $Ax=b$ with a right preconditioner $P$, where $P$ is constructed from $SA$. Popular sketch-and-precondition LS solvers are Blendenpik and LSRN. We show that the sketch-and-precondition technique is not numerically stable for ill-conditioned LS problems. Instead, we propose using an unpreconditioned iterative LS solver on $(AP)y=b$ with $x=Py$ when accuracy is a concern. Provided the condition number of $A$ is smaller than the reciprocal of the unit round-off, we show that this modification ensures that the computed solution has a comparable backward error to the iterative LS solver applied to a well-conditioned matrix. Using smoothed analysis, we model floating-point rounding errors to provide a convincing argument that our modification is expected to compute a backward stable solution even for arbitrarily ill-conditioned LS problems.Comment: 22 page

A1_6 Do you want to hang out?

This paper addresses the simple question: how much time will it take for wet clothes to dry, if they are hung up on a washing line, based on the current weather conditions? The metric form of the Penman equation is used to calculate the evaporation rate of water from a plane surface, which is dependent on the meteorological conditions of ambient temperature, wind speed, relative humidity, and the various properties of air and water at said ambient temperature. Empirically measuring the surface area of, and the mass of water contained in, a wet piece of clothing enables the time taken t for total evaporation to be determined. This paper concludes with an equation for t, provided the above factors are known, and gives example results for different items of clothing

A1_1 Tick, tick, tick... GRBoom!

This paper considers the possibility that a gamma ray burst (GRB) will cause a mass extinction on our planet. The distance over which a low energy GRB would expose a human to a lethal amount of radiation is calculated and found to be approximately 73 kiloparsecs. This indicates that we only need to consider GRBs occurring within the Milky Way galaxy. GRBs are also highly directional; the probability of a GRB striking the Earth is calculated to be 0.06%. From these calculations it is found that a lethal GRB is likely to impact on the Earth once every 328 million years

A1_5 Atomising Death Ray

This report examines the weapons commonly found in science fiction movies which are able to completely atomise a human being, leaving nothing visible behind. To atomise a human body, this report uses the approximation that every bond connecting their atoms must be broken simultaneously. The energy required from such a device is found to be ~3.75 GJ and it is found that it would require 11.06 mg of Deuterium-Tritium to undergo fusion to provide this energy. It is also found that targets will glow deep violet in the visible spectrum shot