A Visual Formalism for Interacting Systems

Interacting systems are increasingly common. Many examples pervade our everyday lives: automobiles, aircraft, defense systems, telephone switching systems, financial systems, national governments, and so on. Closer to computer science, embedded systems and Systems of Systems are further examples of interacting systems. Common to all of these is that some "whole" is made up of constituent parts, and these parts interact with each other. By design, these interactions are intentional, but it is the unintended interactions that are problematic. The Systems of Systems literature uses the terms "constituent systems" and "constituents" to refer to systems that interact with each other. That practice is followed here. This paper presents a visual formalism, Swim Lane Event-Driven Petri Nets, that is proposed as a basis for Model-Based Testing (MBT) of interacting systems. In the absence of available tools, this model can only support the offline form of Model-Based Testing.Comment: In Proceedings MBT 2015, arXiv:1504.0192

Mandated Disclosure, Stock Returns, and the 1964 Securities Acts Amendments

The 1964 Securities Acts Amendments extended the mandatory disclosure requirements that had applied to listed firms since 1934 to large firms traded Over-the-Counter (OTC). We find several pieces of evidence indicating that investors valued these disclosure requirements, two of which are particularly striking. First, a firm-level event study reveals that OTC firms most impacted by the 1964 Amendments had abnormal excess returns of about 3.5 percent in the weeks immediately surrounding the announcement that they had begun to comply with the new requirements. Second, we estimate that the most affected OTC firms had abnormal excess returns ranging between 11.5 and 22.1 percent in the period between when the legislation was initially proposed and when it went it went into force, relative to unaffected listed firms and after adjustment for the standard four-factor model. While we cannot determine how much of shareholders' gains were a transfer from insiders of these same companies, our results suggest that mandatory disclosure causes managers to more narrowly focus on the maximization of shareholder value.

Vulnerability : a view from different disciplines

Practitioners from different disciplines use different meanings and concepts of vulnerability, which, in turn, have led to diverse methods of measuring it. This paper presents a selective review of the literature from several disciplines to examine how they define and measure vulnerability. The disciplines include economics, sociology/anthropology, disaster management, environmental science, and health/nutrition. Differences between the disciplines can be explained by their tendency to focus on different components of risk, household responses to risk and welfare outcomes. In general, they focus either on the risks (at one extreme) or the underlying conditions (or outcomes) at the other. Trade-offs exist between simple measurement schemes and rich conceptual understanding.Environmental Economics&Policies,Health Economics&Finance,Insurance&Risk Mitigation,Economic Theory&Research,Rural Poverty Reduction

Pharmaceuticals, Political Money, and Public Policy: A Theoretical and Empirical Agenda

Congress has consistently failed to solve some serious problems with the cost, effectiveness, and safety of pharmaceuticals. In part, this failure results from the pharmaceutical industry convincing legislators to define policy problems in ways that protect industry profits. By targeting campaign contributions to influential legislators and by providing them with selective information, the industry manages to displace the public’s voice in developing pharmaceutical policy

Multiple Black-necked Stilt Nesting Records in the Rainwater Basin

Black-necked Stilts (Himantopus mexicanus) have increased throughout much of the mid-continent in recent decades (Will 1999, Brinkley 2003, Brinkley and Baicich 2004). Prior to 1970 there were fewer than ten Nebraska records (Sharpe et al. 2001 ). Reports have increased since 1970 and are now annual. Breeding was first recorded in Nebraska in 1985 at Crescent Lake National Wildlife Refuge (Heisinger 1985). Breeding has been more or less regular in the western Sandhills since then (Sharpe et al. 2001) and additional breeding records have occurred in Scotts Bluff (Silcock 2002b ), Keith, and Hall Counties (Silcock 2000b ). In the Rainwater Basin, there was only one record prior to 1996, a specimen collected in Adams County 12 May 1956 (Sharpe et al. 2001). From 1996 through 2004, there were fourteen additional reports. This includes apparent successful breeding at Funk Waterfowl Production Area (WPA), Phelps Co., in 2003 (Silcock 2003). The Rainwater Basin has been experiencing persistent drought since 2000. While drought has been a general theme, occasional localized heavy precipitation events have filled wetlands. Such was the case on 11–12 May 2005 when 3–8 inches of rain fell in portions of the Eastern Rainwater Basin, including Adams, Fillmore, and York Counties. Not long after, Black-necked Stilts were found at multiple wetlands, and several pairs attempted nesting. Below, we summarize observations of nesting Black-necked Stilts in the Eastern Rainwater Basin during 2005

Multiple Black-necked Stilt Nesting Records in the Rainwater Basin

Black-necked Stilts (Himantopus mexicanus) have increased throughout much of the mid-continent in recent decades (Will 1999, Brinkley 2003, Brinkley and Baicich 2004). Prior to 1970 there were fewer than ten Nebraska records (Sharpe et al. 2001 ). Reports have increased since 1970 and are now annual. Breeding was first recorded in Nebraska in 1985 at Crescent Lake National Wildlife Refuge (Heisinger 1985). Breeding has been more or less regular in the western Sandhills since then (Sharpe et al. 2001) and additional breeding records have occurred in Scotts Bluff (Silcock 2002b ), Keith, and Hall Counties (Silcock 2000b ). In the Rainwater Basin, there was only one record prior to 1996, a specimen collected in Adams County 12 May 1956 (Sharpe et al. 2001). From 1996 through 2004, there were fourteen additional reports. This includes apparent successful breeding at Funk Waterfowl Production Area (WPA), Phelps Co., in 2003 (Silcock 2003). The Rainwater Basin has been experiencing persistent drought since 2000. While drought has been a general theme, occasional localized heavy precipitation events have filled wetlands. Such was the case on 11–12 May 2005 when 3–8 inches of rain fell in portions of the Eastern Rainwater Basin, including Adams, Fillmore, and York Counties. Not long after, Black-necked Stilts were found at multiple wetlands, and several pairs attempted nesting. Below, we summarize observations of nesting Black-necked Stilts in the Eastern Rainwater Basin during 2005

A spiral-like disk of ionized gas in IC 1459: Signature of a merging collision

The authors report the discovery of a large (15 kpc diameter) H alpha + (NII) emission-line disk in the elliptical galaxy IC 1459, showing weak spiral structure. The line flux peaks strongly at the nucleus and is more concentrated than the stellar continuum. The major axis of the disk of ionized gas coincides with that of the stellar body of the galaxy. The mass of the ionized gas is estimated to be approx. 1 times 10 (exp 5) solar mass, less than 1 percent of the total mass of gas present in IC 1459. The total gas mass of 4 times 10(exp 7) solar mass has been estimated from the dust mass derived from a broad-band color index image and the Infrared Astronomy Satellite (IRAS) data. The authors speculate that the presence of dust and gas in IC 1459 is a signature of a merger event

External Shear in Quadruply Imaged Lens Systems

We use publicly available N-body simulations and semi-analytic models of galaxy formation to estimate the levels of external shear due to structure near the lens in gravitational lens systems. We also describe two selection effects, specific to four-image systems, that enhance the probability of observing systems to have higher external shear. Ignoring additional contributions from "cosmic shear" and assuming that lens galaxies are not significantly flattened, we find that the mean shear at the position of a quadruple lens galaxy is 0.11, the rms shear is roughly 0.15, and there is roughly a 45% likelihood of external shear greater than 0.1. This is much larger than previous estimates and in good agreement with typical measured external shear. The higher shear primarily stems from the tendency of early-type galaxies, which are the majority of lenses, to reside in overdense regions.Comment: 5 pages, 2 figures, ApJ in press, minor revision