Stochastic level-set method for shape optimisation

We present a new method for stochastic shape optimisation of engineering structures. The method generalises an existing deterministic scheme, in which the structure is represented and evolved by a level-set method coupled with mathematical programming. The stochastic element of the algorithm is built on the methods of statistical mechanics and is designed so that the system explores a Boltzmann-Gibbs distribution of structures. In non-convex optimisation problems, the deterministic algorithm can get trapped in local optima: the stochastic generalisation enables sampling of multiple local optima, which aids the search for the globally-optimal structure. The method is demonstrated for several simple geometrical problems, and a proof-of-principle calculation is shown for a simple engineering structure.Comment: 17 pages, 10 fig

An investigation into the use of intuitive control interfaces and distributed processing for enhanced three dimensional sound localization

This thesis investigates the feasibility of using gestures as a means of control for localizing three dimesional (3D) sound sources in a distributed immersive audio system. A prototype system was implemented and tested which uses state of the art technology to achieve the stated goals. A Windows Kinect is used for gesture recognition which translates human gestures into control messages by the prototype system, which in turn performs actions based on the recognized gestures. The term distributed in the context of this system refers to the audio processing capacity. The prototype system partitions and allocates the processing load between a number of endpoints. The reallocated processing load consists of the mixing of audio samples according to a specification. The endpoints used in this research are XMOS AVB endpoints. The firmware on these endpoints were modified to include the audio mixing capability which was controlled by a state of the art audio distribution networking standard, Ethernet AVB. The hardware used for the implementation of the prototype system is relatively cost efficient in comparison to professional audio hardware, and is also commercially available for end users. The successful implementation and results from user testing of the prototype system demonstrates how it is a feasible option for recording the localization of a sound source. The ability to partition the processing provides a modular approach to building immersive sound systems. This removes the constraint of a centralized mixing console with a predetermined speaker configuration

Jon Mitchell

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Washington Irving

Originally published in 1965. Despite his prolificacy, Washington Irving remained an underexamined figure among literary scholars at the time William L. Hedges published his definitive study of the author in 1965. Most contemporary scholars believed that Irving's central contribution to the American literary tradition was that his work was "polished" and "suave." These scholars maintained that Irving's aristocratic sensibilities defined the stylistic choices of his literary works. To assume this, Hedges contends, is to "both let the man and the work slip beyond one's grasp." Hedges demonstrates that much of Irving's work can be understood in the context of his conflict between federalist and conservative politics. Irving, in other words, found himself incapable of committing to a coherent set of beliefs or attitudes, and this cultural uneasiness manifested itself in his early work. Washington Irving: An American Study, 1802-1832 tries to correct some of the misapprehension about Irving's place in nineteenth-century American literature

Dynamic facilitation explains democratic particle motion of metabasin transitions

Transitions between metabasins in supercooled liquids seem to occur through rapid "democratic" collective particle rearrangements. Here we show that this apparent homogeneous particle motion is a direct consequence of dynamic facilitation. We do so by studying metabasin transitions in facilitated spin models and constrained lattice gases. We find that metabasin transitions occur through a sequence of locally facilitated events taking place over a relatively short time frame. When observed on small enough spatial windows these events appear sudden and homogeneous. Our results indicate that metabasin transitions are essentially "non-democratic" in origin and yet another manifestation of dynamical heterogeneity in glass formers.Comment: 6 pages, 6 figure

Rape Risk Reduction Materials: How Do University Students of Color Perceive the Cultural Relevancy of These Materials?

Few studies have investigated how race and ethnicity influence people\u27s beliefs about rape, or what impact these beliefs have on what and how we teach college students in efforts to raise awareness about rape. The purpose of this study was to gain understanding of how students of color perceive the cultural relevance of materials commonly used on campuses for rape risk reduction education. Participants were African American and Hispanic students at a mid-sized state university. Focus group sessions and interviews were conducted with 23 student participants. Students reported that they found the rape risk reduction materials culturally relevant; however, other revisions of the materials were necessary if the materials were to connect with students. Data analysis, based on the construction of grounded theory and the use of educational criticism, revealed three recurring themes-the influence of popular culture on student perceptions of social situations, the role of racial and ethnic identity development within a global context, and developmental influences on students\u27 ways of constructing knowledge. Therefore, rape risk reduction efforts must be culturally sensitive and developmentally appropriate, and take into consideration the influence of popular culture in order to connect with students

Matrix elements of atomic interaction operators for d sup n configurations

Tabulation of matrix elements of atomic interaction operators for various configuration

Development of improved asbestos reinforced phenolic insulating composites (optimization of physical properties as a function of molding technique and post cure conditions)

Detailed data are presented on phenolic-glass and phenolic-asbestos compounds which compare the effect of compression molding without degas to the effects of four variations of compression molding. These variations were designed to improve elimination of entrapped volatiles and the volatile products of the condensate reaction associated with the cure of phenolic resins. The utilization of conventional methods of degas plus degas by vacuum and directional heat flow methods are involved. Detailed data are also presented on these same compounds, comparing the effect of changes in post-bake time, and post-bake temperature for the five molding techniques

Policy Reflection: Letter of Credit Usage by Defined Benefit Pension Plans in Canada

There is an argument to be made for letting corporations hold off on contributing to their employees’ defined benefit pension plans, as long as there is a guarantee the cash will come eventually. That is the reason that provincial governments began allowing creditworthy companies to instead provide a letter of credit, backed by a Canadian bank, guaranteeing the cash deposit, and secured by the company’s line of credit or some similar facility. Sometimes circumstances are such that a company needs all the cash it can get to grow, or perhaps to manage through tough economic times. Given the sluggish recovery from last decade’s financial crisis and the difficulty for pension funds to grow amid persistent low interest rates, it perhaps is understandable that more companies are using standby letters of credit as IOUs for their employee pensions. The letters provide the companies more flexibility with their capital, and diminish the risk that, should returns to pension funds rise again to more normal rates, there could be “trapped surplus.” It is, however, harder to make a case for why public sector companies and Crown corporations have begun using letters of credit in place of cash deposits to pensions. They certainly do not face the same pressure for capital flexibility, given their revenue is frequently assured, and they face no competition that would pressure them to redirect capital for strategic purposes. And yet, research shows that this is happening, at least to some degree. That should give policymakers pause. Unfortunately, there is a troubling lack of data available as to which organizations have been using letters of credit in place of cash contributions to pension funds. Clearly they are proving useful for some companies, and that the exact reasons vary widely. We observe some companies using the letter of credit option that would appear to have plenty of capital flexibility, so the rationale for their use might not be what the policy anticipated. Meanwhile, it is unclear why so many other companies have chosen not to avail themselves of this temporary pension-funding relief, despite the advantages it offers for avoiding the risk of trapped surpluses. There also remain restrictions on who can underwrite these credit guarantees — regulations do not consider foreign banks and insurance companies acceptable, for example — raising the cost for companies that arrange letters of credit. Taken together, it would seem that there are signs that the policy changes allowing pension-funding relief might be serving their purpose and might be helping companies that could use it, but there is a worrying lack of information to be sure how well they are working and what problems may loom. It certainly seems like a close review is in order. When a Crown corporation is writing IOUs to its defined-benefit pension fund, that is surely a sign that policy-makers are not keeping a close enough eye on the outcomes this policy has led to