Casimir energy inside a triangle

For certain class of triangles (with angles proportional to \fr{\pi}{N}, $N\geq 3$) we formulate image method by making use of the group $G_N$ generated by reflections with respect to the three lines which form the triangle under consideration. We formulate the renormalization procedure by classification of subgroups of $G_N$ and corresponding fixed points in the triangle. We also calculate Casimir energy for such geometries, for scalar massless fields. More detailed calculation is given for odd $N$.Comment: Latex, 13 page

To examine urban open space

Thesis (B.Sc)--University of Hong Kong, 2007.Includes bibliographical references (p. 129-136).published_or_final_versio

On library correctness under weak memory consistency: specifying and verifying concurrent libraries under declarative consistency models

Concurrent libraries are the building blocks for concurrency. They encompass a range of abstractions (locks, exchangers, stacks, queues, sets) built in a layered fashion: more advanced libraries are built out of simpler ones. While there has been a lot of work on verifying such libraries in a sequentially consistent (SC) environment, little is known about how to specify and verify them under weak memory consistency (WMC). We propose a general declarative framework that allows us to specify concurrent libraries declaratively, and to verify library implementations against their specifications compositionally. Our framework is sufficient to encode standard models such as SC, (R)C11 and TSO. Additionally, we specify several concurrent libraries, including mutual exclusion locks, reader-writer locks, exchangers, queues, stacks and sets. We then use our framework to verify multiple weakly consistent implementations of locks, exchangers, queues and stacks

Novel Peak Detection Algorithms for Pileup Minimization in Gamma Ray Spectroscopy

A fast waveform sampling facility has been recently developed and integrated into the VAX-based data acquisition system at the Center for Applied Physical Sciences (CAPS). This study uses the above facility in developing algorithms for digitally determining the basic pulse parameters and tackling the problem of pulse pile-up in Gamma-ray spectroscopy. A number of parameter estimation and digital online peak localisation algorithms are being developed, including a pulse classification technique which uses a simple peak search routine based on the smoothed first derivative method, which gave a percentage error of peak amplitude of less than 1%. The classification technique has the unique feature of cutting down the computation largely by only allowing the event of interest to be executed by a particular algorithm. The set-up was also tested with random signals from a 137Cs test source. Gamma pulses from a 3" Na(TI) scintillation detector were captured as single and double pulses for the purpose of testing the peak detection algorithms. The pulse classification technique was tested successfully on a TMS320C6000 high performance floating-point processor yielding a reduction of the execution time to 2 mse

Novel Peak Detection Algorithms for Pileup Minimization in Gamma Ray Spectroscopy

A fast waveform sampling facility has been recently developed and integrated into the VAX-based data acquisition system at the Center for Applied Physical Sciences (CAPS). This study uses the above facility in developing algorithms for digitally determining the basic pulse parameters and tackling the problem of pulse pile-up in Gamma-ray spectroscopy. A number of parameter estimation and digital online peak localisation algorithms are being developed, including a pulse classification technique which uses a simple peak search routine based on the smoothed first derivative method, which gave a percentage error of peak amplitude of less than 1%. The classification technique has the unique feature of cutting down the computation largely by only allowing the event of interest to be executed by a particular algorithm. The set-up was also tested with random signals from a 137Cs test source. Gamma pulses from a 3" Na(TI) scintillation detector were captured as single and double pulses for the purpose of testing the peak detection algorithms. The pulse classification technique was tested successfully on a TMS320C6000 high performance floating-point processor yielding a reduction of the execution time to 2 mse

Extending Intel-x86 consistency and persistency: formalising the semantics of Intel-x86 memory types and non-temporal stores

Existing semantic formalisations of the Intel-x86 architecture cover only a small fragment of its available features that are relevant for the consistency semantics of multi-threaded programs as well as the persistency semantics of programs interfacing with non-volatile memory. We extend these formalisations to cover: (1) non-temporal writes, which provide higher performance and are used to ensure that updates are flushed to memory; (2) reads and writes to other Intel-x86 memory types, namely uncacheable, write-combined, and write-through; as well as (3) the interaction between these features. We develop our formal model in both operational and declarative styles, and prove that the two characterisations are equivalent. We have empirically validated our formalisation of the consistency semantics of these additional features and their subtle interactions by extensive testing on different Intel-x86 implementations

Taxonomy and structure of the Romanian personality lexicon

We identified 1746 personality-relevant trait-adjectives in a Romanian dictionary, of which 412 were classified as descriptors of dispositions by 10 judges. Self-ratings were collected from 515 participants on those 412 adjectives, and the ratings were factored using principal components analysis. Solutions with different numbers of factors were analysed. The two- and three-factor solutions, respectively, confirmed the Big Two and Big Three of personality traits. A five-factor solution reflected the Big Five model with a fifth factor emphasising Rebelliousness versus Conventionality. The five-factor solution was related to the International Personality Item Pool-Big Five scales, and the highest correlations were indeed between the corresponding factors and scales. A six-factor solution was indicative of the six-factor model as expressed in the HEXACO model, yet with a weak Honesty-Humility factor. Additional analysis with self-ratings from 218 participants on marker-scales for the six-factor solution and on the six scales of the HEXACO did not produce a clear one-to-one correspondence between the two sets of scales, confirming indeed that the six-factor model was only partially found