A review of computer aided interpretation technology for the evaluation of radiographs of aluminum welds

Industrial radiography is a well established, reliable means of providing nondestructive structural integrity information. The majority of industrial radiographs are interpreted by trained human eyes using transmitted light and various visual aids. Hundreds of miles of radiographic information are evaluated, documented and archived annually. In many instances, there are serious considerations in terms of interpreter fatigue, subjectivity and limited archival space. Quite often it is difficult to quickly retrieve radiographic information for further analysis or investigation. Methods of improving the quality and efficiency of the radiographic process are being explored, developed and incorporated whenever feasible. High resolution cameras, digital image processing, and mass digital data storage offer interesting possibilities for improving the industrial radiographic process. A review is presented of computer aided radiographic interpretation technology in terms of how it could be used to enhance the radiographic interpretation process in evaluating radiographs of aluminum welds

A Numerical Analyst Looks at the "Cutoff Phenomenon" in Card Shuffling and Other Markov Chains

Diaconis and others have shown that certain Markov chains exhibit a "cutoff phenomenon" in which, after an initial period of seemingly little progress, convergence to the steady state occurs suddenly. Since Markov chains are just powers of matrices, how can such effects be explained in the language of applied linear algebra? We attempt to do this, focusing on two examples: random walk on a hypercube, which is essentially the same as the problem of Ehrenfest urns, and the celebrated case of riffle shuffling of a deck of cards. As is typical with transient phenomena in matrix processes, the reason for the cutoff is not readily apparent from an examination of eigenvalues or eigenvectors, but it is reflected strongly in pseudosprectra - provided they are measured in the 1-norm, not the 2-norm. We illustrate and explain the cutoff phenomenon with Matlab computations based in part on a new explicit formula for the entries of the $n \times n$ "riffle shuffle matrix", and note that while the normwise cutoff may occur at one point, such as $\frac{3}{2} \log_{2} n$ for the riffle shuffle, weak convergence may occur at an equally precise earlier point such as $\log_{2} n$

Almost Certain Escape from Black Holes

This paper examines how black holes might compute in light of recent models of the black-hole final state. These models suggest that quantum information can escape from the black hole by a process akin to teleportation. They require a specific final state and restrictions on the interaction between the collapsing matter and the incoming Hawking radiation for quantum information to escape. This paper shows that for an arbitrary final state and for generic interactions between matter and Hawking radiation, the quantum information about how the hole was formed and the results of any computation performed by the matter inside the hole escapes with fidelity exponentially close to 1.Comment: 9 Pages, Te

New Products of the 80s & 90s: the Diffusion of Household Technology in the Decade 1985-1995.

As technology continues to evolve at a rapid pace, it has exerted substantial influence on everyone's lives. Over the years various inventions have made their way into homes and have substantially changed the way people work, rest and play. This paper reviews some of these developments and attempts to estimate the extent of these changes with regard to the introduction of five types of household appliances.TECHNOLOGY ; HOUSEHOLD

‘A Nothing Disease?’ An Interpretive Phenomenological exploration of the lived experience of Systemic Lupus Erythematosus (SLE)

The purpose of this research study has been to gain a deeper understanding of the lived experience of systemic lupus erythematosus from the perspective of the person who has the condition. A qualitative interpretive phenomenological approach was adopted influenced by Heidegger (1962) with emphasis on existential and interpretive dimensions over time. This comprehensive study involved a varied and diverse sample of thirty-two participants to allow differing experiences and multiple voices to be heard. The main data collection method was multiple, unstructured interviews. The participants also used a variety of other methods of their own choice including journals, art, music and photography to express ‘what lupus means to you?’ An integrated approach was used combining both the media of the participant’s choice, with an in-depth unstructured interview discussing their media. These varied data collection methods allowed valuable insights into the participant’s everyday world. The study used Wertz’s (1983) method of analysis. Three main findings were identified including, self-doubt and doubt, entrapment and coping and regaining resilience. Self-doubt and doubt explores the participant’s ongoing uncertainty about their symptoms, embodiment and condition and the continual doubts which they experience from others regarding the reality of their illness experience. Entrapment explores the many constraints and barriers that the participants experience in everyday life including the disease itself which enforces loss of control, continual change and disruption, challenges to self identity and integrity, relationships with others and themselves in terms of existential possibilities and goals. There were also a multitude of constraints and barriers imposed on the participants from health services and organisations. All these experiences engender the feeling of a ‘nothing disease’, a feeling of losing themselves. Coping and regaining resilience explored the wealth of coping strategies used within the participant’s everyday life and the ways they had been able to overcome adversity and find ways of moving forward regaining resilience. The study has identified multiple things which negatively impact upon those living with lupus, as well as positively impacts on a person’s ability to live and cope in everyday life. This opens up possible ways for reducing these constraints and that would have a positive impact on the person living with SLE. These constraints indicate some of the priorities health services and organisations should be focusing on to assist those with lupus to regain a more homelike being-in-the-world. The findings have real implications for the development of health care delivery which is person centred, designed around real needs and enables an improved quality of life. This study has been a further important step towards gaining an in-depth understanding of the everyday being-in-the-world of SLE

Fidelity Decay as an Efficient Indicator of Quantum Chaos

Recent work has connected the type of fidelity decay in perturbed quantum models to the presence of chaos in the associated classical models. We demonstrate that a system's rate of fidelity decay under repeated perturbations may be measured efficiently on a quantum information processor, and analyze the conditions under which this indicator is a reliable probe of quantum chaos and related statistical properties of the unperturbed system. The type and rate of the decay are not dependent on the eigenvalue statistics of the unperturbed system, but depend on the system's eigenvector statistics in the eigenbasis of the perturbation operator. For random eigenvector statistics the decay is exponential with a rate fixed precisely by the variance of the perturbation's energy spectrum. Hence, even classically regular models can exhibit an exponential fidelity decay under generic quantum perturbations. These results clarify which perturbations can distinguish classically regular and chaotic quantum systems.Comment: 4 pages, 3 figures, LaTeX; published version (revised introduction and discussion

1944-08-20, Warren to Sophie

https://digitalcommons.chapman.edu/gvtudor_correspondence_postmortem/1010/thumbnail.jp