Perceived noisiness under anechoic, semi-reverberant and earphone listening conditions

Magnitude estimates by each of 31 listeners were obtained for a variety of noise sources under three methods of stimuli presentation: loudspeaker presentation in an anechoic chamber, loudspeaker presentation in a normal semi-reverberant room, and earphone presentation. Comparability of ratings obtained in these environments were evaluated with respect to predictability of ratings from physical measures, reliability of ratings, and to the scale values assigned to various noise stimuli. Acoustic environment was found to have little effect upon physical predictive measures and ratings of perceived noisiness were little affected by the acoustic environment in which they were obtained. The need for further study of possible differing interactions between judged noisiness of steady state sound and the methods of magnitude estimation and paired comparisons is indicated by the finding that in these tests the subjects, though instructed otherwise, apparently judged the maximum rather than the effective magnitude of steady-state noises

The methods of paired comparisons and magnitude estimation in judging the noisiness of aircraft

The point of subjective equality in regard to perceived noisiness for each of 14 pairs of aircraft noises was obtained using both magnitude estimation technique and the method of paired comparisons. Both methods gave approximately the same estimates of the points of subjective equality for the noise pairs, and both showed similar correspondence to predictive physical measures. Nevertheless, the two methods appear to have greater face validity to the listeners. However, the magnitude estimation technique appears to be more efficient; for a given level of reliability it requires approximately 50% of the testing time required by the paired comparison method. The functions relating physical intensity to the estimated magnitude of subjective noisiness had slopes ranging from about .61 to .29 for the aircraft noises employed in this study, indicating a required change of about 5 to 10 db for a doubling in subjective magnitude. Some physical units of noise measurement were found to be very predictive (standard errors of estimate as low as 1.9 db) of the subjective judgements of noisiness

A space communication study Progress report, 15 Sep. 1966 - 15 Mar. 1967

Space communications studies of optimal signal reception, threshold extension, signal detection against noise, channel simulation, and synchronization technique

Analysis of an F.M. Discriminator with Fading Signal plus Additive Gaussian Noise

Fading signal plus additive Gaussian noise applied to frequency modulation discriminator for determining fading effects on threshol

A space communications study Status report, 15 Dec. 1968 - 15 Mar. 1969

Harmonic distortion in frequency demodulator using feedback, delta modulation, recursive signal processing techniques, and multipath fadin

A space communication study Final report, 15 Sep. 1967 - 15 Sep. 1968

Transmitting and receiving analog and digital signals through noisy media - space communications stud

A Space Communications Study Final Report, Sep. 15, 1965 - Sep. 15, 1966

Reception of frequency modulated signals passed through deterministic and random time-varying channel

A space communications study Final report, 15 Sep. 1968 - 15 Sep. 1969

Analog and digital signal reception problems through noisy channels, and computerized digital TV system for space communication

Confined coherence and analytic properties of Green's functions

A simple model of noninteracting electrons with a separable one-body potential is used to discuss the possible pole structure of single particle Green's functions for fermions on unphysical sheets in the complex frequency plane as a function of the system parameters. The poles in the exact Green's function can cross the imaginary axis, in contrast to recent claims that such a behaviour is unphysical. As the Green's function of the model has the same functional form as an approximate Green's function of coupled Luttinger liquids no definite conclusions concerning the concept of "confined coherence" can be drawn from the locations of the poles of this Green's function.Comment: 3 pages, 3 figure

Application of Stanford Watershed Model Concepts to Predict Flood Peaks for Small Drainage Areas

This report embodies two principal objectives: 1) updating rainfall intensity-duration curves for the hydraulic design of culverts and 2) adaptation of the Stanford Watershed Model concept to small drainage basins in Kentucky. The first objective is familiar -- the curves presently being used for the rational method of design were established from an earlier Department study made by E. M. West and W. H. Sammons, issued in July, 1955 (Report No. 2, A Study of Runoff from Small Drainage Areas and the Openings in Attendant Drainage Structures ), and were based on rainfall records then available through 1951. The second objective is somewhat more ambitious and more complex; in its most practical sense, it involves an attempt to equate total rainfall to total runoff and losses throughout a span of years; the losses are then accounted for as evaporation, infiltration, etc. Ideally, all of the significant hydrological parameters may be deduced; then through direct measurements of some essential input descriptors and indirect estimates of others, the water-balance concept may be applied to other basins