Thermal resistance measurement techniques study program Final report

Thermal resistance measurement technique development for transistor

Feasibility model of a high reliability five-year tape transport. Volume 3: Appendices

Detailed drawings of the five year tape transport are presented. Analytical tools used in the various analyses are described. These analyses include: tape guidance, tape stress over crowned rollers, tape pack stress program, response (computer) program, and control system electronics description

On rigidly rotating perfect fluid cylinders

The gravitational field of a rigidly rotating perfect fluid cylinder with gamma- law equation of state is found analytically. The solution has two parameters and is physically realistic for gamma in the interval (1.41,2]. Closed timelike curves always appear at large distances.Comment: 10 pages, Revtex (galley

Predictors of construction time in detached housing projects

Building on previous literature on construction time performance (CTP), this study looks at the extent to which Gross Floor Area (GFA) and Number of Levels (NoL) are important factors in determining the construction time in Australian detached housing projects. Using a dataset of 196 comparable detached housing projects the results show that while GFA and NoL correlate strongly with estimated construction time, they correlated weakly with actual construction time. Dynamically changing events during construction appear to be the reason for the difference. Analyses indicate that cost variations brought about by Design changes, Site management errors; Site workmanship problems and Unforeseen site problems are significant factors in explaining the difference between actual and estimated construction time. Further, these factors affect larger housing projects (>400m2) more significantly than they do smaller projects (<350m2). It would therefore seem that even though GFA on its own has a poor correlation with actual construction time, this improves when teamed with the above cost variations. These results open up avenues for future research to look more closely at the effects of project dynamics (e.g. using causes of cost increases as a proxy) when predicting CTP, rather than relying too heavily on static variables like GFA or NoL. It is important that such variables are taken into account as a basis for teaching and promulgating an analytical basis to predicting construction time

Velocity of Light in Dark Matter with Charge

We propose an interesting mechanism to reconcile the recent experiments of the Michelson-Morley type and slowdown of the velocity of light in dark matter with a fractional electric charge when the index of refraction of dark matter depends on the frequency of a photon. After deriving the formula for the velocity of light in a medium with the index of refraction $n(\omega)$ in a relativistic regime, it is shown that the local anisotropy of the light speed is proportional to the second order in $n(\omega) - 1$. This result implies that the experiments of the Michelson-Morley type do not give rise to a stringent constraint on the slowdown of the velocity of light in dark matter with electric charge.Comment: 10 page

Machine Learning and Irresponsible Inference: Morally Assessing the Training Data for Image Recognition Systems

Just as humans can draw conclusions responsibly or irresponsibly, so too can computers. Machine learning systems that have been trained on data sets that include irresponsible judgments are likely to yield irresponsible predictions as outputs. In this paper I focus on a particular kind of inference a computer system might make: identification of the intentions with which a person acted on the basis of photographic evidence. Such inferences are liable to be morally objectionable, because of a way in which they are presumptuous. After elaborating this moral concern, I explore the possibility that carefully procuring the training data for image recognition systems could ensure that the systems avoid the problem. The lesson of this paper extends beyond just the particular case of image recognition systems and the challenge of responsibly identifying a person’s intentions. Reflection on this particular case demonstrates the importance (as well as the difficulty) of evaluating machine learning systems and their training data from the standpoint of moral considerations that are not encompassed by ordinary assessments of predictive accuracy

Feasibility model of a high reliability five-year tape transport, volume 2

Analysis of the design features of the modularized tape transport renders a life expectancy in excess of five years. Tests performed on the tape transport were directed toward determining its performance capability. These tests revealed that the tape jitter and skew are in the range achieved by high quality digital tape transports. Guidance of the tape in the lateral sense by the use of the two hybrid crowned rollers proved to be excellent. Tracking was maintained within less than one thousandth inch (approximately 2 micrometers). The guidance capability demonstrated makes possible the achievement of the performance objective of 7.2 x 10 to the 9th power storage capability employing 1500 ft. of one inch wide tape with a packing density of 5,000 bits per inch per track on 80 tracks. Also, the machine showed excellent characteristics operating over a wide range of tape speeds. The basic design concept lends itself to growth and adaptation to a wide range of recorder requirements