Reformulation in planning

Reformulation of a problem is intended to make the problem more amenable to efficient solution. This is equally true in the special case of reformulating a planning problem. This paper considers various ways in which reformulation can be exploited in planning

Parameters Affecting Bird Use of Stormwater Impoundments in the Southeastern United States: Implications for Hazardous Wildlife Management at Airports

Stormwater impoundments within Federal Aviation Administration (FAA) citing criteria (10,000 ft from the air operations area) increase the risk of bird-aircraft collisions (strikes) by providing bird habitat. The number of wildlife strikes (97.5% involving birds) reported in the U.S. annually is increasing and, consequently, annual losses to the U.S. civil aviation industry from strikes now exceed $625 million. Wildlife managers must find ways to reduce this risk, while still managing stormwater for environmental quality compliance and safe aircraft ground movements. Existing guidelines for wildlife-hazard management at airports do not quantify the role of pond and landscape characteristics in attracting birds to stormwater impoundments. In a collaborative effort with the FAA and the U.S. Department of Agriculture\u27s Wildlife Services program, we are quantifying bird use of 40 stormwater detention ponds near Auburn, AL, over a two-year period. We will use the observer data and analyses via geographic information systems to develop bird-habitat models and, subsequently, improved BMPs to reduce bird use of stormwater impoundments in and around airports. We will present our development of this project and its objectives, as well as the project\u27s preliminary data and analyses to date

Idiosyncratic Risk During Economic Downturns: Implications for the Use of Event Studies in Securities Litigation

We reported in a recent paper that during the 2008-09 financial crisis, for the average firm, idiosyncratic risk, as measured by variance, increased by five-fold. This finding is important for securities litigation because idiosyncratic risk plays a central role in event study methodology. Event studies are commonly used in securities litigation to determine materiality and loss causation. Many bits of news affect an issuer’s share price at the time of a corporate disclosure that is the subject of litigation. Because of this, even if an issuer’s market–adjusted price changes at the time of the disclosure, one cannot determine with certainty whether the disclosure itself had any effect on price. An event study is used to make a probabilistic assessment of whether in fact it did. Use of event studies generates a certain rate of Type I errors (disclosures that had no actual effect on price being identified as having had an effect) and a certain rate of Type II errors (disclosures that had an actual effect not being identified as such). This paper sets out a simple model of the tradeoff between these Type I and Type II errors. The model is used to establish three fundamental points. First, an economic crisis can radically worsen this tradeoff by making it much more difficult to catch a disclosure of a certain size without introducing more Type I errors. Second, during crisis periods a relaxation of this standard (and hence an increase in the acceptable rate of Type I errors) may actually decrease Type II errors by less than it would in normal times. We prove that whether the decrease is greater or smaller in crisis times depends on whether the disclosure’s actual impact on price is more or less negative than a definable crossover point. Third, whether relaxation of the standard in troubled times would increase or decrease social welfare is ambiguous. It depends on distribution of potentially actionable disclosures in terms of their actual impact on price and the social costs and social benefits of imposing liability for disclosures of each given level of actual negative impact on price

Sintering of screen-printed platinum thick films for electrode applications

Pt electrodes with a 6-8-μm thickness were produced on alumina substrates by a double-print Pt screen-printing process that included a sequential heat treatment at 600 °C and 1300 °C. This process improved the final sintered double-print film because the first printed layer acted as a sintering template for the second printed layer. The sintered Pt films have a 95% coverage of the alumina surface, 92% density, 0.73-μm average surface roughness, and 16.10−5 Ω cm resistivity. The sintering behavior of Pt films exhibited three stages of densification: Stage I (T °C < 700 °C), exhibiting neck growth, and Stage II (700 < T °C < 1300 °C), exhibiting grain growth, have activation energies of 64 kJ/mol and 125 kJ/mol, respectively. Stage III exhibits a decrease in shrinkage due to Pt coalescence and island formation. The transition temperature, 700 °C, between Stages I and II corresponds to an anomalous increase in surface roughness and resistivity. The thickness of Pt films was a critical parameter for achieving alumina surface coverage. Uniaxial pressing of dried Pt films increased densification and reduced the surface roughness of double-print Pt film