Jonathan Lenchner

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We consider a class of geometric facility location problems in which the goal is to determine a set <i>X</i> of disks given by their centers <i>(t<sub>j</sub>)</i> and radii <i>(r<sub>j</sub>)</i> that cover a given set of demand points <i>Y&#8712;R</i><sup>2</sup> at the smallest possible cost. We consider cost functions of the form(More)
We describe an inexpensive robot that serves as a physical autonomic element, capable of navigating, mapping and monitoring data centers with little or no human involvement, even ones that it has never seen before. Through a series of real experiments and simulations, we establish that the robot is sufficiently accurate, efficient and robust to be of(More)
The sharp rise in energy usage in data centers, fueled by increased IT workload and high server density, and coupled with a concomitant increase in the cost and volatility of the energy supply, have triggered urgent calls to improve data center energy efficiency. In response, researchers have developed energy-aware IT systems that slow or shut down servers(More)
The game of Jeopardy!i features four types of strategic decision-making: 1) Daily Double wagering; 2) Final Jeopardy! wagering; 3) selecting the next square when in control of the board; and 4) deciding whether to attempt to answer, i.e., ''buzz in.'' Strategies that properly account for the game state and future event probabilities can yield a huge boost(More)
Getting workers to share knowledge in situations where " knowledge " is the primary asset making them valuable is a pressing problem in many organizations – leading to what we call " the knowledge worker's prisoner's dilemma. " Interesting variants of this dilemma arise in the contexts of customer support and server system administration. We begin by(More)
We describe an inexpensive autonomous robot capable of navigating previously unseen data centers and monitoring key metrics such as air temperature<sup>1</sup>. The robot provides real-time navigation and sensor data to commercial IBM software, thereby enabling real-time generation of the data center layout, a thermal map and other visualizations of energy(More)
Major advances in Question Answering technology were needed for IBM Watson 1 to play Jeopardy! 2 at championship level – the show requires rapid-fire answers to challenging natural language questions, broad general knowledge, high precision, and accurate confidence estimates. In addition, Jeopardy! features four types of decision making carrying great(More)
Computer server management is an important component of the global IT (information technology) services business. The providers of server management services face unrelenting efficiency challenges in order to remain competitive with other providers. Server system administrators (SAs) represent the majority of the workers in this industry, and their primary(More)
In 1893 J. J. Sylvester [8] posed the following celebrated problem: Given a finite collection of points in the affine plane, not all lying on a line, show that there exists a line which passes through precisely two of the points. Sylvester's problem was reposed by Erd˝ os in 1944 [4] and later that year a proof was given by Gallai [6]. Since then, many(More)