3,694 research outputs found
Semper Paratus? The Coast Guard is Not Equipped to Fight
As early in World War II as June 1943, the Coast Guard\u27s commandant, Vice Admiral Russell R. Waesche, directed his administrative planning staff to prepare a document entitled The Function of the Coast Guard and It’s Place in the Scheme of Government. For this study, Waesche indicated his desire to emphasize why the service should be reinstated under the Department of the Treasury-and not be retained by the Department of the Navy in peace time.
Some Sources Of Variation In Structural Characteristics Of Douglas-Fir Bark
This study examines variations in structure and formation of Douglas-fir bark. Development of a classification system based on the external appearance of the bark surface that would correlate with anatomical characteristics of the bark was not possible. Modification of bark by fungi was observed to occur in several specific ways, such as attacking cell walls of sclereids, removing contents from lumina of various cell types, and affecting formation of cork layers in regions associated with radial checks and fissures in the bark
An Observation About Frostman Shifts
A classical theorem of Frostman says that if B is a Blaschke product (or any inner function), then its Frostman shifts Bw = (B − w)(1 – w¯B)−1 are Blaschke products for all |w| \u3c 1 except possibly for w in a set of logarithmic capacity zero. If B is a Frostman Blaschke product, equivalently an inner multiplier for the space of Cauchy transforms of measures on the unit circle, we show that for all |w| \u3c 1, Bw is indeed another Frostman Blaschke product
APU diaphragm testing
The Auxiliary Power Unit (APU) fuel (hydrazine) tanks were removed from the Columbia Shuttle during major modification of the vehicle, because of long-term hydrazine compatibility concerns. The three tanks had been in service for 11 years. As part of an effort to determine whether the useful life of the fuel tanks can be extended, examination of the ethylene propylene rubber (EPR) diaphragm and the metal casing from one of the APU tanks was required. NASA Johnson Space Center Propulsion and Power Division requested the NASA Johnson Space Center White Sands Test Facility to examine the EPR diaphragm for signs of degradation that might limit the life of its function in the APU tank and to examine the metal casing for signs of surface corrosion. No appreciable degradation of the EPR diaphragm was noted. A decrease in the tensile properties was found, but tensile failure is considered unlikely because the metal casing constrains the diaphragm, preventing it from elongating more than a few percent. The titanium casing showed no evidence of surface corrosion
Implementation of a Pulsed-Laser Measurement System in the National Transonic Facility
A remotely-adjustable laser transmission and imaging system has been developed for use in a high-pressure, cryogenic wind tunnel. Implementation in the National Transonic Facility has proven the system suitable for velocity and signal lifetime measurements over a range of operating conditions. The measurement system allows for the delivery of high-powered laser pulses through the outer pressure shell and into the test section interior from a mezzanine where the laser is free from environmental disturbances (such as vibrations and excessive condensation) associated with operation of the wind tunnel. Femtosecond laser electronic excitation tagging (FLEET) was utilized to provide freestream velocity measurements, and first results show typical data that may be obtained using the system herein described
Triggering social interactions:chimpanzees respond to imitation by a humanoid robot and request responses from it
Even the most rudimentary social cues may evoke affiliative responses in humans and promote socialcommunication and cohesion. The present work tested whether such cues of an agent may also promotecommunicative interactions in a nonhuman primate species, by examining interaction-promoting behavioursin chimpanzees. Here, chimpanzees were tested during interactions with an interactive humanoid robot, whichshowed simple bodily movements and sent out calls. The results revealed that chimpanzees exhibited twotypes of interaction-promoting behaviours during relaxed or playful contexts. First, the chimpanzees showedprolonged active interest when they were imitated by the robot. Second, the subjects requested ‘social’responses from the robot, i.e. by showing play invitations and offering toys or other objects. This study thusprovides evidence that even rudimentary cues of a robotic agent may promote social interactions inchimpanzees, like in humans. Such simple and frequent social interactions most likely provided a foundationfor sophisticated forms of affiliative communication to emerge
[Introduction to] The Cauchy Transform
The Cauchy transform of a measure on the circle is a subject of both classical and current interest with a sizable literature. This book is a thorough, well-documented, and readable survey of this literature and includes full proofs of the main results of the subject. This book also covers more recent perturbation theory as covered by Clark, Poltoratski, and Aleksandrov and contains an in-depth treatment of Clark measures.https://scholarship.richmond.edu/bookshelf/1094/thumbnail.jp
The Backward Shift on the Space of Chauchy Transforms
This note examines the subspaces of the space of Cauchy transforms of measures on the unit circle that are invariant under the backward shift operator f --\u3e z-1 (f—f (0)). We examine this question when the space of Cauchy transforms is endowed with both the norm and weak* topologies
IkeaBot: An autonomous multi-robot coordinated furniture assembly system
We present an automated assembly system that directs the actions of a team of heterogeneous robots in the completion of an assembly task. From an initial user-supplied geometric specification, the system applies reasoning about the geometry of individual parts in order to deduce how they fit together. The task is then automatically transformed to a symbolic description of the assembly-a sort of blueprint. A symbolic planner generates an assembly sequence that can be executed by a team of collaborating robots. Each robot fulfills one of two roles: parts delivery or parts assembly. The latter are equipped with specialized tools to aid in the assembly process. Additionally, the robots engage in coordinated co-manipulation of large, heavy assemblies. We provide details of an example furniture kit assembled by the system.Boeing Compan
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