The KW-boundary hybrid digital waveguide mesh for room acoustics applications

The digital waveguide mesh is a discrete-time simulation used to model acoustic wave propagation through a bounded medium. It can be applied to the simulation of the acoustics of rooms through the generation of impulse responses suitable for auralization purposes. However, large-scale three-dimensional mesh structures are required for high quality results. These structures must therefore be efficient and also capable of flexible boundary implementation in terms of both geometrical layout and the possibility for improved mesh termination algorithms. The general one-dimensional N-port boundary termination is investigated, where N depends on the geometry of the modeled domain and the mesh topology used. The equivalence between physical variable Kirchoff-model, and scattering-based wave-model boundary formulations is proved. This leads to the KW-hybrid one-dimensional N-port boundary-node termination, which is shown to be equivalent to the Kirchoff- and wave-model cases. The KW-hybrid boundary-node is implemented as part of a new hybrid two-dimensional triangular digital waveguide mesh. This is shown to offer the possibility for large-scale, computationally efficient mesh structures for more complex shapes. It proves more accurate than a similar rectilinear mesh in terms of geometrical fit, and offers significant savings in processing time and memory use over a standard wave-based model. The new hybrid mesh also has the potential for improved real-world room boundary simulations through the inclusion of additional mixed modeling algorithms

The Paradoxes of Paramountcy: Regional Rivalries and the Dynamics of American Hegemony in East Asia

The US plays a pivotal role in the contemporary international system and is able to shape that system to reflect its own interests. At a time when the contemporary international order is in a period of flux, and when the position of the US itself is subject to a range of internal pressures and external challenges, it is useful to try and gauge both the character of, and limits to, US hegemony. We shall examine the dynamics of US power in the context of East Asia, the region most likely to generate a challenge to US hegemony in the coming century. The first part of the paper considers the concept of hegemony. Following this, we place America's relationship with East Asia in historical context, before considering its current relationships with China, Japan and the region as a whole. The central argument we advance is that the character of US hegemony is changing and this is closely connected to the wider transformation of the nation-state system

Lineages of Liberalism and Miracles of Modernization: The World Bank, the East Asian Trajectory and the International Development Debate

Until recently the World Bank, arguably the most prestigious and one of the most powerful producers of international development knowledge, played an important role in encouraging the perception that the East Asian trajectory was a veritable miracle of capitalist development. This article begins with a brief discussion of the changes in the World Bank's understanding of development over the past 30 or 40 years. This is followed by an examination of the Bank's efforts to accommodate the East Asian trajectory within the dominant Anglo-American narrative on international development. It is argued that, in the context of the shifting contours of the international political economy and of important changes to the dominant international discourse on development, the World Bank has played a crucial role in domesticating the East Asian Miracle to the dominant liberal narrative of progress and in facilitating the wider reinvention of liberalism in the post-1945 period

APEC, ASEAN+3, and American Power: The History and Limits of the New Regionalism in the Asia-Pacific

In the 1990s both non-state-centred and state-centred regional processes of integration have emerged as increasingly important counterpoints to the globalisation project and US globalism. In some parts of the world, most notably Western Europe, regional identity reflects long-standing processes of economic and political integration, which have been facilitated by shared political and even cultural practices. In the "Asia-Pacific", by contrast, not only are processes of regional integration and coordination of more recent vintage, the very definition of the region has been a far more highly contested and far more incompletely realised project. The failure of the Asia Pacific Economic Cooperation (APEC) forum to even begin to realise the hopes of its advocates is a powerful reminder of just how difficult regional and political cooperation in such circumstances can be. What is of far greater long-term significance than the faltering APEC project is the contradictory impact of US hegemony on regional processes. This article begins by exploring the limits of the new regionalism in the post-Cold War East Asia via a focus on the Cold War history of the region. It then turns to the changing character of US hegemony in the post-Cold War era. We emphasize that in the context of the complex shifts and continuities of the past five decades there are far more serious constraints on the new regionalism in the Asia-Pacific than in Europe, or the Americas, where regionalisation and regionalism is arguably most advanced. We also look closely at APEC and ASEAN+3, paying particular attention to the role of the United States, which has played a pivotal role in shaping regional outcomes. Finally, we consider the prospects for a distinctive East Asian form of regionalism grounded in a much narrower conception of the Asia-Pacific. We conclude that while there are profound limits on the coherence and unity of ASEAN+3 in the context of the continued salience of US power in the region, APEC has now clearly been displaced by ASEAN+3 as the most significant embodiment of the new regionalism in the Asia-Pacific

An Advanced, Three-Dimensional Plotting Library for Astronomy

We present a new, three-dimensional (3D) plotting library with advanced features, and support for standard and enhanced display devices. The library - S2PLOT - is written in C and can be used by C, C++ and FORTRAN programs on GNU/Linux and Apple/OSX systems. S2PLOT draws objects in a 3D (x,y,z) Cartesian space and the user interactively controls how this space is rendered at run time. With a PGPLOT inspired interface, S2PLOT provides astronomers with elegant techniques for displaying and exploring 3D data sets directly from their program code, and the potential to use stereoscopic and dome display devices. The S2PLOT architecture supports dynamic geometry and can be used to plot time-evolving data sets, such as might be produced by simulation codes. In this paper, we introduce S2PLOT to the astronomical community, describe its potential applications, and present some example uses of the library.Comment: 12 pages, 10 eps figures (higher resolution versions available from http://astronomy.swin.edu.au/s2plot/paperfigures). The S2PLOT library is available for download from http://astronomy.swin.edu.au/s2plo

Canonical Forms in Interactive Exercise Assistants

Interactive exercise assistants support students in practicing exercises, and acquiring procedural skills. Many mathematical topics can be practiced in such assistants. Ideally, an interactive exercise assistant not only validates final answers, but also comments on intermediate steps submitted by a student, provides hints on how to proceed, and presents worked-out examples. For these purposes, fine control over the symbolic simplification procedures of the underlying mathematical machinery is needed. In this paper, we introduce views for mathematical expressions. A view defines an equivalence relation by choosing a canonical form of mathematical expressions. We use views to track and recognize intermediate answers, to help in presenting expressions to a user, and to control the granularity of the steps in worked-out examples. We develop the concept of a view, discuss the laws it satisfies, and show how views are composed, which means that they can be used for multiple exercise classes.

Nonlinear filtering of high dimensional, chaotic, multiple timescale correlated systems

This dissertation addresses theoretical and numerical questions in nonlinear filtering theory for high dimensional, chaotic, multiple timescale correlated systems. The research is motivated by problems in the geosciences, in particular oceanic or atmospheric estimation and climate prediction. As the capability and need to further resolve the physics models on finer scales continues, greater spatial and temporal scales become present and the dimension of the models becomes increasingly large. In the atmospheric sciences, these models can be of the order $\mathcal{O}(10^9)$ degrees of freedom and require assimilation of the order $\mathcal{O}(10^7)$ observations during a single day. The models are chaotic and the observing sensors may be correlated with the physical processes themselves. The goal of the dissertation is to develop theoretical results that can provide the mathematical justification for new filtering algorithms on a lower dimensional problem, and to develop novel methods for dealing with issues that plague particle filtering when applied to high dimensional, chaotic, multiple timescale correlated systems. The first half of the dissertation is theoretical and addresses the question of approximating the continuous time nonlinear filtering equation for a multiple timescale correlated system by an averaged filtering equation in the limit of large timescale separation. The first result in this direction is within the context of a slow-fast system with correlation between the slow process and the observation process, and when we are only interested in estimating functions of the slow process. The main result is that we can retrieve a rate of convergence and that there is a metric generating the topology of weak convergence, such that the marginal filter converges to the averaged filter at the given rate in the limit of large timescale separation. The proof uses a probabilistic representation (backward doubly stochastic differential equation) of the dual process to the unnormalized filter, and sharp estimates on the transition density and semigroup of the fast process. The second theoretical result of the dissertation addresses the same question for a broader problem, where the slow signal dynamics include an intermediate timescale forcing. We prove that the marginal filter converges in probability to the average filter for a metric that generates the topology of weak convergence. The method of proof is by showing tightness of the measure-valued process, characterizing the weak limits, and proving the limit is unique. The perturbation test function (also known as method of corrector) is used to deal with the intermediate timescale forcing term, where the corrector is the solution of a Poisson equation. The second half of the dissertation develops filtering algorithms that leverage the theoretical results from the first half of the thesis to produce particle filtering methods for the averaged filtering equation. We also develop particle methods that address the issue of particle collapse for filtering on general high dimensional chaotic systems. Using the two timescale Lorenz 1996 atmospheric model, we show that the reduced order particle filtering methods are shown to be at least an order of magnitude faster than standard particle methods. We develop a method for particle filtering when the signal and observation processes are correlated. We also develop extensions to controlled optimal proposal particle filters that improve the diversity of the particle ensemble when tested on the Lorenz 1963 model. In the last chapter of the dissertation, we adopt a dynamical systems viewpoint to address the issue of particle collapse. This time the goal is to exploit the chaotic properties of the system being filtered to perform assimilation in a lower dimensional subspace. A new approach is developed which enables data assimilation in the unstable subspace for particle filtering. We introduce the idea of future right-singular vectors to produce projection operators, enabling assimilation in a lower dimensional subspace. We show that particle filtering algorithms using dynamically generator projection operators, in particular the future right-singular vectors, outperforms standard particle methods in terms of root-mean-square-error, diversity of the particle ensemble, and robustness when applied to the single timescale Lorenz 1996 model

A Possible protective effect of nut consumption on risk of coronary heart-disease: the adventist health study

Background -Although dietary factors are suspected to be important determinants of coronary heart disease (CHD) risk, the direct evidence is relatively sparse. Methods. -The Adventist Health Study is a prospective cohort investigation of 31 208 non-Hispanic white California Seventh-Day Adventists. Extensive dietary information was obtained at baseline, along with the values of traditional coronary risk factors. These were related to risk of definite fatal CHD or definite nonfatal myocardial infarction

Counselor Allegiance and Client Expectancy in Neuroscience-Informed Cognitive-Behavior Therapy: A 12-Month Qualitative Follow-Up

This article presents summative findings from a 12-month multiphase mixed-methods pilot study examining counselor and client perceptions of neuroscience-informed cognitive-behavior therapy (nCBT) following clinical application. Results from the first 6 months of the study indicated that the counselor\u27s and client\u27s beliefs about the credibility and effectiveness of nCBT (i.e., expectancy) remained stable from pretreatment to 6 months into treatment. The fourth phase of data collection at the 12-month interval followed an explanatory sequential process whereby the qualitative data were connected to earlier merged quantitative data to better understand initial findings from the first 6 months of the study. Results indicate that counselors\u27 initial comprehension and familiarity with the model, counselor–client trust, counselor delivery and suggestion, and client willingness to practice outside of session were key components to the development of counselor and client belief (expectancy) in the model. Implications for nCBT theory development and application are discussed