Seasonal Drift of \u3ci\u3eLethocerus Americanus\u3c/i\u3e (Hemiptera: Belostomatidae) in a Lake Superior Tributary

Drifting adult Lethocerus americanus were captured and retained by an inclined-screen smolt trap during two field seasons in the Bois Brule River, Wisconsin. Seasonal peaks of drift occurred in spring for 4 weeks following ice out and in autumn for 7 -8 weeks from mid-September through ice formation, and may have continued under ice cover when our gear was not operated. These findings are consistent with the known movement pattern of these insects to fly from lentic habitats to streams to overwinter but also suggest longitudinal movement via drift, perhaps to reach specific overwintering sites. Drift was significantly correlated with declining water temperatures in 1989 but not in 1990. Most drift occurred at water temperatures less than 12°C. There was no correlation between drift and river discharge. Drift rates were consistently low with a maximum by volume of 9 animals per 10,000 m3

Color image processing and object tracking workstation

A system is described for automatic and semiautomatic tracking of objects on film or video tape which was developed to meet the needs of the microgravity combustion and fluid science experiments at NASA Lewis. The system consists of individual hardware parts working under computer control to achieve a high degree of automation. The most important hardware parts include 16 mm film projector, a lens system, a video camera, an S-VHS tapedeck, a frame grabber, and some storage and output devices. Both the projector and tapedeck have a computer interface enabling remote control. Tracking software was developed to control the overall operation. In the automatic mode, the main tracking program controls the projector or the tapedeck frame incrementation, grabs a frame, processes it, locates the edge of the objects being tracked, and stores the coordinates in a file. This process is performed repeatedly until the last frame is reached. Three representative applications are described. These applications represent typical uses and include tracking the propagation of a flame front, tracking the movement of a liquid-gas interface with extremely poor visibility, and characterizing a diffusion flame according to color and shape

Log-Concave Duality in Estimation and Control

In this paper we generalize the estimation-control duality that exists in the linear-quadratic-Gaussian setting. We extend this duality to maximum a posteriori estimation of the system's state, where the measurement and dynamical system noise are independent log-concave random variables. More generally, we show that a problem which induces a convex penalty on noise terms will have a dual control problem. We provide conditions for strong duality to hold, and then prove relaxed conditions for the piecewise linear-quadratic case. The results have applications in estimation problems with nonsmooth densities, such as log-concave maximum likelihood densities. We conclude with an example reconstructing optimal estimates from solutions to the dual control problem, which has implications for sharing solution methods between the two types of problems

Epistemic Abstainers, Epistemic Martyrs, and Epistemic Converts

An intuitive view regarding the epistemic significance of disagreement says that when epistemic peers disagree, they should suspend judgment. This abstemious view seems to embody a kind of detachment appropriate for rational beings; moreover, it seems to promote a kind of conciliatory inclination that makes for irenic and cooperative further discussion. Like many strategies for cooperation, however, the abstemious view creates opportunities for free-riding. In this essay, the authors argue that the believer who suspends judgment in the face of peer disagreement is vulnerable to a kind of manipulation on the part of more tenacious peers. The result is that the abstemious view can have the effect of encouraging dogmatism

Funding Resilient Infrastructure in New Jersey: Attitudes Following a Natural Disaster

Recent major natural disasters in New Jersey have demonstrated the need to increase the resilience of transportation infrastructure. This research examines public attitudes toward revenue sources that can be dedicated to protecting vulnerable areas, most notably the transportation linkages on which the state depends. A statewide survey was conducted to gather data approximately four months following Superstorm Sandy, the costliest natural disaster in the state’s history. The authors’ objective was to sample public attitudes while the impacts of the disaster were still fresh. They found little support for temporary tax increases to improve resiliency, with the most positive support for taxing visitors (i.e., a hotel and recreational tax) and for a 30-year bond measure (i.e., taxing the future). This observation seemingly contradicts broad support for investing in new infrastructure, as well as maintaining and protecting existing infrastructure. Multivariate analysis to understand the underlying attitudes toward raising revenue found that more left-leaning or communitarian attitudes are associated with more support for gasoline, income, or sales taxes devoted to mitigating vulnerability. Those who supported investment in transit and protecting infrastructure also were more likely to support these taxes. There was no parallel finding of factors associated with taxing visitors or issuing bonds

Diffraction from visible lattice points and k-th power free integers

We prove that the set of visible points of any lattice of dimension at least 2 has pure point diffraction spectrum, and we determine the diffraction spectrum explicitly. This settles previous speculation on the exact nature of the diffraction in this situation, see math-ph/9903046 and references therein. Using similar methods we show the same result for the 1-dimensional set of k-th power free integers with k at least 2. Of special interest is the fact that neither of these sets is a Delone set --- each has holes of unbounded inradius. We provide a careful formulation of the mathematical ideas underlying the study of diffraction from infinite point sets.Comment: 45 pages, with minor corrections and improvements; dedicated to Ludwig Danzer on the occasion of his 70th birthda

Using multiple sensors for printed circuit board insertion

As more and more activities are performed in space, there will be a greater demand placed on the information handling capacity of people who are to direct and accomplish these tasks. A promising alternative to full-time human involvement is the use of semi-autonomous, intelligent robot systems. To automate tasks such as assembly, disassembly, repair and maintenance, the issues presented by environmental uncertainties need to be addressed. These uncertainties are introduced by variations in the computed position of the robot at different locations in its work envelope, variations in part positioning, and tolerances of part dimensions. As a result, the robot system may not be able to accomplish the desired task without the help of sensor feedback. Measurements on the environment allow real time corrections to be made to the process. A design and implementation of an intelligent robot system which inserts printed circuit boards into a card cage are presented. Intelligent behavior is accomplished by coupling the task execution sequence with information derived from three different sensors: an overhead three-dimensional vision system, a fingertip infrared sensor, and a six degree of freedom wrist-mounted force/torque sensor