Induced Lorentz-Violating Chern-Simons Term in QED: Uncovering Short Distance Interaction Terms in the Effective Lagrangian without the Shadow of Regularization

We show that the correctly evaluated effective Lagrangian should include short-distance interaction terms which have been avoided under the protection of usual regularization and must be properly identified and reinstated if regularization is to be removed. They have special physical and mathematical significance as well as restoring gauge invariance and suppressing divergence in the effective Lagrangian. The rich structure of the short-distance interaction terms can open up challenging opportunities where the conventional regularization with rigid structure is unavailable and inappropriate. It becomes clear that gauge invariance is preserved with or without regularization and therefore there is no Lorentz-Violating Chern-Simons term in QED.Comment: 5 pages. Talk presented at the Second Meeting on CPT and Lorentz Symmetry CPT'01, August 15-18, 2001, Bloomington, Indian

A sequential Monte Carlo approach to computing tail probabilities in stochastic models

Sequential Monte Carlo methods which involve sequential importance sampling and resampling are shown to provide a versatile approach to computing probabilities of rare events. By making use of martingale representations of the sequential Monte Carlo estimators, we show how resampling weights can be chosen to yield logarithmically efficient Monte Carlo estimates of large deviation probabilities for multidimensional Markov random walks.Comment: Published in at http://dx.doi.org/10.1214/10-AAP758 the Annals of Applied Probability (http://www.imstat.org/aap/) by the Institute of Mathematical Statistics (http://www.imstat.org

Efficient importance sampling for Monte Carlo evaluation of exceedance probabilities

Large deviation theory has provided important clues for the choice of importance sampling measures for Monte Carlo evaluation of exceedance probabilities. However, Glasserman and Wang [Ann. Appl. Probab. 7 (1997) 731--746] have given examples in which importance sampling measures that are consistent with large deviations can perform much worse than direct Monte Carlo. We address this problem by using certain mixtures of exponentially twisted measures for importance sampling. Their asymptotic optimality is established by using a new class of likelihood ratio martingales and renewal theory.Comment: Published at http://dx.doi.org/10.1214/105051606000000664 in the Annals of Applied Probability (http://www.imstat.org/aap/) by the Institute of Mathematical Statistics (http://www.imstat.org

Maxima of asymptotically Gaussian random fields and moderate deviation approximations to boundary crossing probabilities of sums of random variables with multidimensional indices

Several classical results on boundary crossing probabilities of Brownian motion and random walks are extended to asymptotically Gaussian random fields, which include sums of i.i.d. random variables with multidimensional indices, multivariate empirical processes, and scan statistics in change-point and signal detection as special cases. Some key ingredients in these extensions are moderate deviation approximations to marginal tail probabilities and weak convergence of the conditional distributions of certain ``clumps'' around high-level crossings. We also discuss how these results are related to the Poisson clumping heuristic and tube formulas of Gaussian random fields, and describe their applications to laws of the iterated logarithm in the form of the Kolmogorov--Erd\H{o}s--Feller integral tests.Comment: Published at http://dx.doi.org/10.1214/009117905000000378 in the Annals of Probability (http://www.imstat.org/aop/) by the Institute of Mathematical Statistics (http://www.imstat.org

Photo Based 3D Walkthrough

The objective of 'Photo Based 3D Walkthrough' is to understand how image-based rendering technology is used to create virtual environment and to develop aprototype system which is capable ofproviding real-time 3D walkthrough experience by solely using 2D images. Photo realism has always been an aim of computer graphics in virtual environment. Traditional graphics needs a great amount of works and time to construct a detailed 3D model andscene. Despite the tedious works in constructing the 3D models andscenes, a lot ofefforts need to beput in to render the constructed 3D models and scenes to enhance the level of realism. Traditional geometry-based rendering systems fall short ofsimulating the visual realism of a complex environment and are unable to capture and store a sampled representation ofa large environment with complex lighting and visibility effects. Thus, creating a virtual walkthrough ofa complex real-world environment remains one of the most challenging problems in computer graphics. Due to the various disadvantages of the traditional graphics and geometry-based rendering systems, image-based rendering (IBR) has been introduced recently to overcome the above problems. In this project, a research will be carried out to create anIBR virtual walkthrough by using only OpenGL and C++program without the use of any game engine or QuickTime VR function. Normal photographs (not panoramic photographs) are used as the source material in creating the virtual scene and keyboard is used asthe main navigation tool in the virtual environment. The quality ofthe virtual walkthrough prototype constructed isgood withjust a littlejerkiness

Refusing to stand still, reaching out to the public

The Chinese art collections and exhibitions of the Art Museum of the Chinese University of Hong Kong are known for high artistic and educational standards. However, historically, the general public has not been closely involved with the museum because of its distant location from the centre of the city and its strong academic reputation. In this paper, the author, who contributed to the show and in planning outreach programs, will introduce education and outreach strategies to facilitate the promotion of the exhibition and to encourage public engagement with the museum. She will give suggestions and her vision for the future

Hedging Prime Interest Rate and Bank for Cooperatives Rates by Using Financial Futures for South Dakota Agricultural Cooperatives

The main objective of this study is to evaluate the feasibility of hedging the· prime interest rate and Bank for Cooperatives seasonal rates with financial futures for South Dakota agricultural cooperatives. Most agricultural cooperatives borrow mainly from commercial banks and the Bank for Cooperatives, and the rates depend on the prime rate and Bank for Cooperatives seasonal loan rates (BC rates). This study will examine whether a local cooperative might use financial futures to hedge these two interest rates. Local cooperatives must identify whether hedging is feasible for their seasonal loan with the commercial bank or Bank for Cooperatives. Also, three Bank for Cooperatives· seasonal rates will be examined to see if differences exist. They are Omaha, Spokane and St Paul rates. In this study, hedging strategy will be based on the portfolio model which assumes that the hedger desires to minimize the variance of the portfolio\u27s returns. The hedger\u27s loan portfolio consists of hedged and unhedged positions. A risk minimizing hedge ratio is an estimated coefficient that indicates the proportion of the loan portfolio to be hedged

The formation of owners’ corporations in Hong Kong’s private housing estates: A probit evaluation of Mancur Olson’s group theory

Abstract: This paper uses a probit model to analyse 100 observations in terms of three hypotheses about the formation of owners’ corporations in high-density private housing estates in Hong Kong within the context of Mancur Olson’s group theory. The findings do not reject the theory, revealing that it is more likely for an older urban estate with fewer owners to form owners’ corporations. The discussion includes a brief introduction to Olson’s group theory and the development of the probit analysis. Some speculative thoughts about public participation in local level urban management and planning are offered in the conclusion.published_or_final_versio