Numerical Analysis of Strategic Contingent Claims Models

We study the numerical properties of a class of models recently introduced to calculate the values of corporate bonds and other corporate liabilities. Starting from a discrete-time extensive form game representing the consequences of financial distress, these strategic contingent claims models are associated with a particular free-boundary problem. Here we consider the properties of alternative solution techniques applied to this problem. We discuss four solution techniques of the finite difference type: explicit solutions, explicit solutions of the log transformed model, implicit solutions on a regular grid, and dynamically remeshed implicit solutions. To our knowledge this last method has not previously been employed in financial applications. We find that the use of dynamic remeshing can speed calculation solutions enormously. This opens the way to applying strategic contingent claims models in practical applications.     

Scalability of parallel spatial direct numerical simulations on intel hypercube and IBM SP1 and SP2

The implementation and performance of a parallel spatial direct numerical simulation (PSDNS) approach on the Intel iPSC/860 hypercube and IBM SP1 and SP2 parallel computers is documented. Spatially evolving disturbances associated with laminar-to-turbulent transition in boundary-layer flows are computed with the PSDNS code. The feasibility of using the PSDNS to perform transition studies on these computers is examined. The results indicate that PSDNS approach can effectively be parallelized on a distributed-memory parallel machine by remapping the distributed data structure during the course of the calculation. Scalability information is provided to estimate computational costs to match the actual costs relative to changes in the number of grid points. By increasing the number of processors, slower than linear speedups are achieved with optimized (machine-dependent library) routines. This slower than linear speedup results because the computational cost is dominated by FFT routine, which yields less than ideal speedups. By using appropriate compile options and optimized library routines on the SP1, the serial code achieves 52–56 Mflops on a single node of the SP1 (45 percent of theoretical peak performance). The actual performance of the PSDNS code on the SP1 is evaluated with a real world simulation that consists of 1.7 million grid points. One time step of this simulation is calculated on eight nodes of the SP1 in the same time as required by a Cray Y/MP supercomputer. For the same simulation, 32-nodes of the SP1 and SP2 are required to reach the performance of a Cray C-90. A 32 node SP1 (SP2) configuration is 2.9 (4.6) times faster than a Cray Y/MP for this simulation, while the hypercube is roughly 2 times slower than the Y/MP for this application.     

Eco-Friendly Colorimetric Nanofiber Design: Halochromic Sensors with Tunable pH-Sensing Regime Based on 2-Ethyl-2-Oxazoline and 2-n-Butyl-2-Oxazoline Statistical Copolymers Functionalized with Alizarin Yellow R

Colorimetric nanofibers provide visual, easy-to-interpret sensors for personal use as well as advanced applications. The potential of 2-n-butyl-2-oxazoline (B) and 2-ethyl-2-oxazoline (E) statistical copolymers as a universal, versatile support platform for nanofibrous halochromic sensor design is demonstrated. These polymers are electrospinnable from eco-friendly solvent systems, while wettability, moist adsorption capacity, and water-solubility of the membranes can be easily tuned by changing the B/E monomer ratio, ensuring wide applicability. The halochromic sensing functionality is introduced by incorporating the alizarin yellow R (AYR) chromophore, which is covalently modified with an ethyl ester-group or a short poly(2-n-butyl-2-oxazoline) chain, which is demonstrated to simultaneously prevent dye-leaching and allows tuning of the halochromic pH-sensing window. The colorimetric nanofibrous sensors reversibly respond toward aqueous solutions of different pH, (hydrochloric) acid and alkaline (ammonia) vapors, and several biogenic amines with detection limits as low as 5 ppb. Tunability of sensor responsivity, sensitivity, and pKa via manipulation of dye–polymer interactions, determined by support polymer structure and semi-crystallinity, as well as the chain length of the AYR-modified polymer, are discussed. Preliminary proof-of-principle studies indicate the potential of the developed sensors for sub-ppm biogenic amine vapor detection, which may serve as the basis for future applications in food packaging or breath analysis.     

Linking and Layout: Exploring the Integration of Text and Visualization in Storytelling

Modern web technologies are enabling authors to create various forms of text visualization integration for storytelling. This integration may shape the stories' flow and thereby affect the reading experience. In this paper, we seek to understand two text visualization integration forms: (i) different text and visualization spatial arrangements (layout), namely, vertical and slideshow; and (ii) interactive linking of text and visualization (linking). Here, linking refers to a bidirectional interaction mode that explicitly highlights the explanatory visualization element when selecting narrative text and vice versa. Through a crowdsourced study with 180 participants, we measured the effect of layout and linking on the degree to which users engage with the story (user engagement), their understanding of the story content (comprehension), and their ability to recall the story information (recall). We found that participants performed significantly better in comprehension tasks with the slideshow layout. Participant recall was better with the slideshow layout under conditions with linking versus no linking. We also found that linking significantly increased user engagement. Additionally, linking and the slideshow layout were preferred by the participants. We also explored user reading behaviors with different conditions.     

A comparative study of memory‐type control charts under normal and contaminated normal environments

Cumulative sum (CUSUM) and exponentially weighted moving average (EWMA) control charts are commonly used to detect small changes in the parameters of production processes. Recently, a new control structure was introduced, named as mixed EWMA–CUSUM control chart, which combined both charts. The current study provides a detailed comparison of these three types of control charts when the process parameters are unknown under normal and contaminated normal environments. Performance measures average run length and different percentiles of run length distribution are used for comparison purposes. We investigate six different location estimators with the structures of the three memory charts and study their robustness properties. Copyright © 2015 John Wiley & Sons, Ltd.     

Multicriteria Decision-Making Using Fuzzy Measures

We are interested in the formulation of multicriteria decision functions based on the use of a measure over the space of criteria. Specifically, the relationship between the criteria is expressed using a monotonic set measure. We then use the Choquet integral to construct decision functions based on the measure. We look at a number of different decision functions generated from specific classes of measures.     

Some hidden "regularities" in a school mental health program and their relation to intended outcomes.

Investigated contact frequency and duration "regularities" as they relate to program objectives of educational and personal development. Children seen 1, 2, or 3 times/wk by nonprofessional child aides in a school mental health project did not differ significantly either on initial referral status or on outcome measures. Directionally, the 3 times/wk group had more serious initial problems; however, there were no consistent referral differences between the once and twice a week groups. Children seen least frequently improved most directionally. For 3 separate year groups, there were no referral or outcome differences between children who continued in the project and those who terminated; hence, no justification was found for differences in the length of intervention. Findings have implications both for the practices of this specific program and, more generally, for other types of helping interventions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)