Justified Belief Change

Justification Logic is a framework for reasoning about evidence and justification. Public Announcement Logic is a framework for reasoning about belief changes caused by public announcements. This paper develops JPAL, a dynamic justification logic of public announcements that corresponds to the modal theory of public announcements due to Gerbrandy and Groeneveld. JPAL allows us to reason about evidence brought about by and changed by Gerbrandy--Groeneveld-style public announcements.

Invariant barriers to reactive front propagation in fluid flows

We present theory and experiments on the dynamics of reaction fronts in two-dimensional, vortex-dominated flows, for both time-independent and periodically driven cases. We find that the front propagation process is controlled by one-sided barriers that are either fixed in the laboratory frame (time-independent flows) or oscillate periodically (periodically driven flows). We call these barriers burning invariant manifolds (BIMs), since their role in front propagation is analogous to that of invariant manifolds in the transport and mixing of passive impurities under advection. Theoretically, the BIMs emerge from a dynamical systems approach when the advection-reaction-diffusion dynamics is recast as an ODE for front element dynamics. Experimentally, we measure the location of BIMs for several laboratory flows and confirm their role as barriers to front propagation.

Experimental acute type B aortic dissection: different sites of primary entry tears cause different ways of propagation

Many dissections seem to also have a retrograde component. The aim of the study was to evaluate different sites of primary entry tears and the propagation of the dissecting membrane, antegrade and retrograde, in an experimental model of acute type B aortic dissection.

Barriers to front propagation in ordered and disordered vortex flows

We present experiments on reactive front propagation in a two-dimensional (2D) vortex chain flow (both time-independent and time-periodic) and a 2D spatially disordered (time-independent) vortex-dominated flow. The flows are generated using magnetohydrodynamic forcing techniques, and the fronts are produced using the excitable, ferroin-catalyzed Belousov-Zhabotinsky chemical reaction. In both of these flows, front propagation is dominated by the presence of burning invariant manifolds (BIMs) that act as barriers, similar to invariant manifolds that dominate the transport of passive impurities. Convergence of the fronts onto these BIMs is shown experimentally for all of the flows studied. The BIMs are also shown to collapse onto the invariant manifolds for passive transport in the limit of large flow velocities. For the disordered flow, the measured BIMs are compared to those predicted using a measured velocity field and a three-dimensional set of ordinary differential equations that describe the dynamics of front propagation in advection-reaction-diffusion systems.

Beyond Belief: Japanese Approaches to the Meaning of Religion

For several centuries, Japanese scholars have argued that their nation’s culture—including its language, religion and ways of thinking—is somehow unique. The darker side of this rhetoric, sometimes known by the English term “Japanism” (nihon-jinron), played no small role in the nationalist fervor of the late-nineteenth and early twentieth centuries. While much of the so-called “ideology of Japanese uniqueness” can be dismissed, in terms of the Japanese approach to “religion,” there may be something to it. This paper highlights some distinctive—if not entirely unique—features of the way religion has been categorized and understood in Japanese tradition, contrasting these with Western (i.e., Abrahamic), and to a lesser extent Indian and Chinese understandings. Particular attention is given to the priority of praxis over belief in the Japanese religious context. Des siècles durant, des chercheurs japonais ont soutenu que leur culture – soit leur langue, leur religion et leurs façons de penser – était en quelque sorte unique. Or, sous son jour le plus sombre, cette rhétorique, parfois désignée du terme de « japonisme » (nihon-jinron), ne fut pas sans jouer un rôle déterminant dans la montée de la ferveur nationaliste à la fin du XIXe siècle, ainsi qu’au début du XXe siècle. Bien que l’on puisse discréditer pour l’essentiel cette soi-disant « idéologie de l’unicité japonaise », la conception nippone de la « religion » constitue, quant à elle, un objet d’analyse des plus utiles et pertinents. Cet article met en évidence quelques caractéristiques, sinon uniques du moins distinctives, de la manière dont la religion a été élaborée et comprise au sein de la tradition japonaise, pour ensuite les constrater avec les conceptions occidentale (abrahamique) et, dans une moindre mesure, indienne et chinoise. Une attention toute particulière est ici accordée à la praxis plutôt qu’à la croyance dans le contexte religieux japonais.

Experimental Comparison of Bluetooth and WiFi Signal Propagation for Indoor Localisation

Systems for indoor positioning using radio technologies are largely studied due to their convenience and the market opportunities they offer. The positioning algorithms typically derive geographic coordinates from observed radio signals and hence good understanding of the indoor radio channel is required. In this paper we investigate several factors that affect signal propagation indoors for both Bluetooth and WiFi. Our goal is to investigate which factors can be disregarded and which should be considered in the development of a positioning algorithm. Our results show that technical factors such as device characteristics have smaller impact on the signal than multipath propagation. Moreover, we show that propagation conditions differ in each direction. We also noticed that WiFi and Bluetooth, despite operating in the same radio band, do not at all times exhibit the same behaviour.