Bounded Error Schemes for the Wave Equation on Complex Domains

This paper considers the application of the method of boundary penalty terms (SAT) to the numerical solution of the wave equation on complex shapes with Dirichlet boundary conditions. A theory is developed, in a semi-discrete setting, that allows the use of a Cartesian grid on complex geometries, yet maintains the order of accuracy with only a linear temporal error-bound. A numerical example, involving the solution of Maxwell’s equations inside a 2-D circular wave-guide demonstrates the efficacy of this method in comparison to others (e.g., the staggered Yee scheme)—we achieve a decrease of two orders of magnitude in the level of the L₂-error.     

Enhanced security protocol engineering through a unified multidimensional framework

Multidimensional security protocol engineering is effective for creating cryptographic protocols since it encompasses a variety of design, analysis, and deployment techniques, thereby providing a higher level of confidence than individual approaches offer. SPEAR II, the Security Protocol Engineering and Analysis Resource II, is a protocol engineering tool built on the foundation of previous experience garnered during the SPEAR I project in 1997. The goal of the SPEAR II tool is to facilitate cryptographic protocol engineering and to aid users in distilling the critical issues during an engineering session by presenting them with an appropriate level of detail and guiding them as much as possible during design, analysis and implementation. The SPEAR II tool currently consists of four components that have been integrated into one consistent and unified graphical interface: a protocol specification environment (GYPSIE), a GNY statement construction interface (visual GNY), a Prolog-based GNY analysis engine (GYNGER), and a message rounds calculator. The multidimensional approach realized by SPEAR II is combined with a graphical interface that focuses on making specification of a protocol and its associated conditions for formal analysis as straight forward and painless as possible. Experiments that we have conducted confirm that the analysis engine is able to generate accurate proofs for achievable GNY-based goals, while preliminary usability experiments have indicated that the interface utilized by SPEAR II is both expressive and simple to use for specifying cryptographic protocols and constructing logic statements pertaining to these protocols.     

Restricted overlapping balancing domain decomposition methods and restricted coarse problems for the Helmholtz problem

Overlapping balancing domain decomposition methods and their combination with restricted additive Schwarz methods are proposed for the Helmholtz equation. These new methods also extend previous work on non-overlapping balancing domain decomposition methods toward simplifying their coarse problems and local solvers. They also extend restricted Schwarz methods, originally designed to overlapping domain decomposition and Dirichlet local solvers, to the case of non-overlapping domain decomposition and/or Neumann and Sommerfeld local solvers. Finally, we introduce coarse spaces based on partitions of unity and planes waves, and show how oblique projection coarse problems can be designed from restricted additive Schwarz methods. Numerical tests are presented.     

Freud's group psychology revisited: An opportunity missed.

This brief essay was sparked by a long overdue new book (Person, 2001) dealing with Freud's 1921 monograph on group psychology. This volume, regrettably, failed to relate Freud's promising, precursory ideas to his own behavior as a leader, as well as to subsequent seminal contributions to psychoanalytic and group theories and to group psychotherapy. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Relapse crises and coping among dieters.

We examined situational antecedents of dieting relapse crises and dieters' attempts to cope with temptations to overeat. We analyzed postreatment interviews with 57 obese Ss with Type II diabetes, comparing situations in which Ss lapsed with those in which they overcame temptation to overeat. Cluster analysis yielded 3 categories of relapse crises: mealtime, low-arousal, and emotional upset situations. The cluster differed in outcome: Upset situations almost always resulted in overeating; situational factors, especially food-related cues, increased relapse risk; but performance of coping was the strongest correlate of outcome. Cognitive and behavioral coping responses were each equally associated with positive outcomes. When Ss reported combining both types of coping, they were less likely to report overeating. The dynamics of relapse crises among dieters resemble those that govern relapse crises in addictive behaviors. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Large deviation theorems for empirical types of Markov chainsconstrained to thin sets

An irreducible Markov chain with stationary transition probabilities on a finite directed graph is considered. The probability of large deviations of the random variable denoting the empirical type of the first n transitions is investigated     

Train Tracks and Confluent Drawings

Confluent graphs capture the connection properties of train tracks, offering a very natural generalization of planar graphs, and—as the example of railroad maps shows—are an important tool in graph visualization. In this paper we continue the study of confluent graphs, introducing strongly confluent graphs and tree-confluent graphs. We show that strongly confluent graphs can be recognized in NP (the complexity of recognizing confluent graphs remains open). We also give a natural elimination ordering characterization of tree-confluent graphs, and we show that this class coincides with the (6,2)-chordal bipartite graphs. Finally, we define outerconfluent graphs and identify the bipartite permutation graphs as a natural subclass.     

Correlates of osteopenia in patients with cystic fibrosis

The responses to heat shock in Tritrichomonas mobilensis, a squirrel monkey parasite and Tritrichomonas augusta, an amphibian trichomonad, were evaluated by means of metabolic labeling with [35S]methionine. Electrophoretically separated trichomonad proteins synthesized at different temperatures were visualized by autoradiography and the label incorporation quantitated by a trichloroacetic acid precipitation procedure. A considerable difference in thermotolerance between the two species was found as the protein synthesis reached a maximum at 41 C in T. mobilensis and 37 C in T. augusta. The latter tolerated temperature increases 13 C above normal cultivation temperatures as compared to only 4 C thermotolerance range above normal in T. mobilensis. Major heat shock proteins (Hsps) were expressed in both T. mobilensis (with apparent Mr 94, 72, and 58 kDa) and T. augusta (Mr 94, 70, and 56 kDa) as revealed by autoradiography. Western blot analysis with polyclonal antibody against DnaK of Escherichia coli showed the presence of antigenic Hsp70 homologs in both trichomonads. Similarly, a polyclonal antibody against Hsp60 with broad interspecies cross-reactivity detected Hsp60 homologs in both T. mobilensis and T. augusta. The anti-DnaK antibody cross-reacted with a T. mobilensis protein localized in Golgi apparatus as demonstrated by immunoelectron microscopy. Immunocytochemistry on trichomonad frozen sections revealed the presence of the Hsp60 homolog in light-microscopic granules corresponding to hydrogenosomes.