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The author developed a simple computer program for the in-class simulation of the repeated prisoner's dilemma game with student-designed strategies. He describes the basic features of the software and presents two examples for the use of the program in teaching the problems of cooperation among profit-maximizing agents.

This paper develops a model of exchange rate determination in partially liberalized post-socialist economy that operates under soft budget constraints in nontradable sectors. The model captures the factors that determine the evolution of a country's external balance during the initial phase of economic liberalization. Three types of disturbances are the center of analysis: liberalization of trade and foreign exchange regime, devaluation, and price liberalization. We show that the real exchange rate appreciation may either improve or worsen the trade balance depending on the sources of this appreciation. Thus, we argue that the real exchange rate cannot reflect true country's competitiveness unless all sectors are equally exposed to hard budget constraints. The model implications are further analyzed through the empirical evidence on the relationship between the real exchange rate and trade balance in three selected East European countries.

In an experts-assisted decision making paradigm, the information collection design becomes a strategic variable under a weak assumption that the final decision is dependent on the design used to collect information as well. As a result, the same information of the experts and the decision maker about the problem can potentially produce different final decisions for different information collection designs. The implication is that a decision maker can strategically select a design which serves his/her objective. This paper uses a Bayesian estimation methodology for combining experts' information with the decision maker's prior. An information collection process is designed by setting constraints on this model. Several designs are developed here using such controlled factors as a one-stage versus a two-stage decision process, experts' rank ordering, and group versus individual lobbying/consultation. An example is provided to illustrate the applicability of the concept. It is shown that the information produced in the process of producing a decision can also give insights into the impacts of the decision maker and the experts on the decision.

Tholeiitic rocks of the Ferrar Large Igneous Province (FLIP) occur in a linear belt from the Theron Mountains to Horn Bluff in the Transantarctic Mountains and extend into southeastern Australasia. The FLIP was emplaced during the initial stages of Gondwana break-up from a source suggested to be in the proto-Weddell Sea region. Magma transport from its source (Weddell triple junction) was controlled by an Early Jurassic zone of extension. The FLIP comprises the Dufek intrusion, Ferrar Dolerite sills and dykes (sheet intrusions), and extrusive rocks consisting of pyroclastic strata overlain by Kirkpatrick Basalt lavas. The Dufek intrusion occurs in deformed supracrustal rocks of the foldbelt along the paleo-Pacific Gondwana margin. A few sills were emplaced in basement rocks, but the majority of the sheet intrusions occur in flat-lying Devonian to Triassic Beacon strata. Only in the central Transantarctic Mountains (CTM) and south and north Victoria Land (SVL, NVL) are extrusive rocks preserved overlying Beacon strata. The greatest cumulative thicknesses of magmatic rocks (ca. 2 km) occur in areas where lavas are preserved (CTM and SVL). Sheet intrusions have complex relationships. Dyke swarms (sensu stricto) are unknown and dykes cutting basement rocks are uncommon. Nevertheless, these dykes, including a 30-m-wide dyke in SVL, suggest that some magmas locally migrated up through basement rocks. In CTM and NVL the outcrop belt has a width of about 160 km. Sills originally extended farther toward the plate margin but have been cut out by erosion and Cenozoic faulting, most clearly in CTM; geophysical data suggest extension under the East Antarctic ice sheet for at least 100 km. Although Early Jurassic extension is documented in CTM, major rift-bounding faults have not been observed. Models for magma emplacement include transport along the axis of the Transantarctic Mountains and off-axis transport from major rift-bounding faults. Contrasts in geochemistry between lavas of NVL (MgO=6-7%) and CTM (MgO=2-4%) and the presence of massive dolerite bodies (CTM, SVL) suggest discrete episodes and locations of magma emplacement, and that there was no long range interconnection along the mountain range in supracrustal rocks.

The encrustation of Paleozoic rhynchonelliform brachiopods has been studied for decades, but modern brachiopods have not received similar scrutiny. The discovery of abundant subtropical brachiopods from the Southeast Brazilian Bight provides an unprecedented opportunity to assess epibiont abundance, diversity, and encrustation patterns in modern brachiopod assemblages. Across the outer shelf, encrustation frequencies vary among taxa, from mean values of 0.45% for Platidia to 9.3% for Argyrotheca. Encrustation frequencies for Bouchardia increase from 1.6% on the outer shelf to 84% on the inner shelf. Larger valves are encrusted more frequently, and epibionts preferentially colonize valve interiors. Increased encrustation on the inner shelf may reflect the greater surface areg of larger hosts, longer exposure of dead shells, water-mass characteristics, sedimentation rates, productivity, or other factors that vary with depth. Inner-shelf brachiopods exhibit encrustation frequencies comparable to those reported for epifaunal bivalves. The epibiont fauna is dominated by bryozoans and serpulids, with minor roles played by spirorbids, bivalves, barnacles, foraminifera, algae, and other taxa. Epibiont abundance at each site is highly variable, but sites are similar in rank importance of epibiont taxa. A different suite of epibionts colonized Paleozoic brachiopods, but similar patterns of encrustation have been observed, including preferential settlement according to valve morphology. These results provide a baseline for evaluating the encrustation of modern bivalves and ancient brachiopods, and may elucidate the macroevolutionary history of epibionts and their relationship to their hosts. © 2004, SEPM (Society for Sedimentary Geology).

In 1993, during the removal of a diesel and a gasoline underground storage tank at the municipal garage of the Village of Kohler, Sheboygan County, Wisconsin, soil testing revealed environmental contamination at the site. A site investigation revealed the possibility of a second on-site source of petroleum contamination. Limited historical data and the present usage of structures within the suspected source area precluded the use of most invasive sampling methods and most geophysical techniques. A fluxgate magnetometer survey, followed by confirmatory excavation, was conducted at the site. The fluxgate magnetometer survey identified nine possible magnetic anomalies within the 18 × 25 m area. The subsequent excavation near the anomalies revealed the presence of five paired and two individual 2000 L underground storage tanks. The fluxgate magnetometer survey, although affected by the proximity of buildings, was able to detect the buried tanks within 3 m of the brick structures, using a 1.5 × 1.5 m sampling array.

Children in today's society face many stresses from a variety of sources that have a major impact on thier psychosocial adjustment and academic performance in school. These stressful events and thier consequences on the quality of life and academic success are particularly significant among low-income and ethnic minority students in American society. Many schools have adopted strategies to help students who are impacted by stressful life events to deal affectively with their problems in an attempt to reduce school failure and school dropout rates among these students. Most notable among these strategies are school-based mental health programs including the establishment of school-based mental health teams which seek to proactively address individual student concerns while improving the general climate of schools. The evidence seems to support the claim that these school-based services have a positive impact on students' social and emotional well-being as well as on their academic achievements. However, with more careful monitoring and much more consistent support from administrators and policy makers, these school-based approaches can more fully realize their potential to enhance the quality of life and to positively impact the future of many poor and ethnic minority students.

In scientific imaging, it is crucial to obtain precise images to facilitate accurate observations for the given application. However, often times the imaging equipment used to acquire such images introduces error into the observed image. Therefore, there is a fundamental need to remove the error associated with these images in order to facilitate accurate observations. This study investigates the effectiveness of an image processing technique utilizing an iterative deconvolution algorithm to remove error from micro-CT images. This technique is applied to several sets of in-vivo micro CT scans of mice, and its effectiveness is evaluated by qualitative comparison of the resultant thresholded binary images to thresholded binary images produced by more conventional image processing techniques; namely Gaussian filtering and straight thresholding. Results for this study suggest that iterative deconvolution as a pre-processing step produces superior qualitative results as compared to the more conventional methods tested. The groundwork for future quantitative verification is motivated. ©2005 IEEE.

The primary goal of this research was to provide image processing support to aid in the identification of those subjects most affected by bone loss when exposed to weightlessness and provide insight into the causes for large variability. Past research has demonstrated that genetically distinct strains of mice exhibit different degrees of bone loss when subjected to simulated weightlessness. Bone loss is quantified by in vivo computed tomography (CT) imaging. The first step in evaluating bone density is to segment gray scale images into separate regions of bone and background. Two of the most common methods for implementing image segmentation are thresholding and edge detection. Thresholding is generally considered the simplest segmentation process which can be obtained by having a user visually select a threshold using a sliding scale. This is a highly subjective process with great potential for variation from one observer to another. One way to reduce inter-observer variability is to have several users independently set the threshold and average their results but this is a very time consuming process. A better approach is to apply an objective adaptive technique such as the Riddler / Calvard method. In our study we have concluded that thresholding was better than edge detection and pre-processing these images with an iterative deconvolution algorithm prior to adaptive thresholding yields superior visualization when compared with images that have not been pre-processed or images that have been pre-processed with a filter.

The problem of characterizing the relationship between packet size and network delay has received little attention in the field. Research in that area has been limited to either simulation studies or empirical observations that are detached from analytic traffic modeling. From a queueing viewpoint, it is simple to show that these three variables are inter-related, which necessitates a more careful study. We present a traffic model of a router fed by ON/OFF-type sources with heavy-tailed burst sizes. The traffic model considered is consistent with the evidence that Web traffic is heavy-tailed. The analysis cases that are considered establish a quantitative characterization of the complex relationship among packet payload and header sizes, traffic burstiness, and router queueing delay. © 2004 IEEE.

We present a genetic algorithm for heuristically solving a cost minimization problem applied to communication networks with threshold based discounting. The network model assumes that every two nodes can communicate and offers incentives to combine flow from different sources. Namely, there is a prescribed threshold on every link, and if the total flow on a link is greater than the threshold, the cost of this flow is discounted by a factor α. A heuristic algorithm based on genetic strategy is developed and applied to a benchmark set of problems. The results are compared with former branch and bound results using the CPLEX® solver. For larger data instances we were able to obtain improved solutions using less CPU time, confirming the effectiveness of our heuristic approach. Copyright© 2003, Lawrence Erlbaum Associates, Inc.

Temporal and spatial analysis was applied to a sequence of cloud top pressure (CTP) images and cloud optical thickness (TAU) images, and a storm tracking algorithm was proposed. A sequence of storm tracks from the satellite images was developed from the satellite images. Composite images were created by projecting ahead in time and substituting the first valid pixel for missing data, and a variety of CTP and TAU cut-off values were used to identify regions of interest. The region correspondences were determined from one time frame to another which yielded the storm center coordinates. The obtained tracks were compared to the storm tracks computed from sea level pressure data by matching the results first in time and then in spatial distance.

The objective of this study is to compare geometric-based and evolutionary techniques for tracking storm systems from sequences of satellite images. Analysis was applied to the International Satellite Cloud Climatology Project low resolution D1 database for selected storm systems during the month of September, 1988. During this time period there were two exceptionally long tracks of major hurricane systems, Hurricanes Gilbert and Helene. Cloud top pressure and cloud optical thickness were used to identify storm systems. The ability of the geometric-based and evolutionary techniques to generate tracks through storm regions was assessed. Differences in final tracking results between the two techniques resulted not only from the differences in methodology but also form differences in the type of preprocessed input used by each of the techniques. Tracking results were compared to results disseminated by the Colorado State/Tropical Prediction Center and maintained by the National Hurricane Center in Miami, Florida. For the hurricanes investigated in this study, both techniques were able to generate tracks which followed either most or some of the portions of the hurricanes. The evolutionary algorithm was in general able to maintain good continuity along the tracks but, with no knowledge of overall region movement, was unable to discern which of two possible directions would be best to pursue in cases where there were tow or more equally close storm systems components. The geometric method was able to maintain a smooth track close to the course of the hurricane except for confusion primarily at the beginning and/or end of tracks.

Several working or experimental management systems use expert systems techniques for fault management purposes. Although the effort in the area is still growing, most of the expert fault management systems developed were built in an ad-hoc and unstructured basis simply transferring the knowledge of the human expert into an automated system. However, to meet future challenges, a theoretical foundation for fault management must be established aiming to bridge the gap between the working systems and research, and to provide a general structured model easily expandable to future networks. In this paper an algorithm is proposed to simplify the set of clustered alarms. This algorithm is based on the techniques widely used in the Logic Design field to simplify switching functions. The performance of the proposed algorithm is analyzed and the results are compared to those of a traditional algorithm.

A quality assurance system is essential for the credibility and structured growth of anaesthesiology-based transoesophageal echocardiography (TEE) programmes. We have developed software (Q/A Kappa), involving a 400- line source code, capable of directly reporting kappa correlation coefficient values, using external reviewer interpretations as the 'gold standard', and thereby allowing systematic assessment of the validity of intraoperative echocardiographic interpretation. This paper presents assessment of the validity of 240 intraoperative anaesthesiologists' echocardiographic interpretations, and, in addition, the results of field testing of this prototypical software. Data, derived from consecutive cardiac surgery patients, consisted of standardized two-dimensional transoesophageal echocardiographic, colour flow and Doppler imaging sequences. Intraoperative and off-line 'gold standard' TEE interpretations were compared for 19 fields or variables using the Q/A Kappa program. The kappa correlation coefficients were highly variable and dependent on the examination field, ranging from 0.08 for apical regional wall motion scores to 1.00 for tricuspid regurgitation grade, left atrial measurement, aortic valve anatomy and left ventricular long axis and short axis global function. The correlation coefficients were also operator dependent. These data (480 interpretations) were also manually integrated into the equation required for calculation of values of the variable kappa correlation coefficient. The relationship between Q/A Kappa-derived values and manually calculated values was highly significant (p < 0.001; r = 1.0). The implications and possible explanations of the results for particular examination fields are discussed. This study also demonstrates successful seamless functioning of this software program from data entry, segmentation into tables and valid statistical analysis. These findings suggest that it is practical to provide sophisticated continuous quality improvement TEE data on a routine basis.