Probability Density Function Method for Observing Reconstructed Attractor Structure

Probability density function (PDF) method is proposed for analysing the structure of the reconstructed attractor in computing the correlation dimensions of RR intervals of ten normal old men. PDF contains important information about the spatial distribution of the phase points in the reconstructed attractor. To the best of our knowledge, it is the first time that the PDF method is put forward for the analysis of the reconstructed attractor structure. Numerical simulations demonstrate that the cardiac systems of healthy old men are about 6 - 6.5 dimensional complex dynamical systems. It is found that PDF is not symmetrically distributed when time delay is small, while PDF satisfies Gaussian distribution when time delay is big enough. A cluster effect mechanism is presented to explain this phenomenon. By studying the shape of PDFs, that the roles played by time delay are more important than embedding dimension in the reconstruction is clearly indicated. Results have demonstrated that the PDF method represents a promising numerical approach for the observation of the reconstructed attractor structure and may provide more information and new diagnostic potential of the analyzed cardiac system.     

Expertise Reversal Effect and Its Implications for Learner-Tailored Instruction

The interactions between levels of learner prior knowledge and effectiveness of different instructional techniques and procedures have been intensively investigated within a cognitive load framework since mid-90s. This line of research has become known as the expertise reversal effect. Apart from their cognitive load theory-based prediction and explanation, patterns of empirical findings on the effect fit well those in studies of Aptitude Treatment Interactions (ATI) that were originally initiated in mid-60s. This paper reviews recent empirical findings associated with the expertise reversal effect, their interpretation within cognitive load theory, relations to ATI studies, implications for the design of learner-tailored instructional systems, and some recent experimental attempts of implementing these findings into realistic adaptive learning environments.     

Programmatic choices and the demand for theatre: the case of Flemish theatres

Theatre experts generally agree that the Flemish theatre has flourished artistically over the period 1980–2000. Attendance, on the other hand, has declined significantly. Following Lancaster’s characteristics approach, we identify several output characteristics of individual theatre productions. Using a panel of 59 Flemish theatres, we examine the impact on demand of both these output characteristics and of traditional determinants such as own price, income and the price of substitutes. Differences in the relevant geographical market for touring and non-touring theatres are considered. We find that the nature of the artistic output affects demand. Theatregoers prefer large productions (in terms of cast size), plays by Dutch-speaking playwrights and revivals of old productions. Own price and consumer income have the expected negative and positive effects on attendance. Observed trends toward a decreasing proportion of new plays, an increasing presence of plays by Dutch-speaking playwrights, and increasing consumer income had a stimulating effect on attendance. These trends have been offset, however, by trends toward smaller cast sizes and higher ticket prices as well as by unobserved factors captured by time dummies. The net result has been a considerable drop in attendance.

Two games in town: a comparison of dealer and auction prices in contemporary visual arts markets

The article tests a couple of hypotheses relating to markets where demand is not taken as a given, but subject to sophisticated and encompassing price-building strategies. The study uses a data set that provides quoted dealer prices for medium-sized works of 100 leading visual artists from 1970 to 2004. These data are compared with auction price results for works by the same artists. The study reports significant discrepancies with respect to the relationship between the age of artists and prices paid for their works in the two markets, and with respect to general price developments in the two markets as measured by indices.

Geographic clustering of economic activity: The case of prominent western visual artists

This article compiles original data relating to artists’ place of birth and work migration patterns using various art history dictionaries. The broad historic pattern, from the 13th to the 20th century, of the birth locations of prominent artists is examined, followed by a detailed study of the work migration patterns of prominent artists in two important situations, namely Renaissance Italy and France in part of the 19th century. The evidence indicates a marked clustering of activity of prominent artists, both arising from birth location and migration patterns. Some possible explanations for the observed patterns are briefly outlined.

From a Means to an End: Patenting in the 1999 Danish ‘Act on Inventions’ and its Effect on Research Practice

This paper examines the potential pitfalls for academic research associated with goal displacements in the implementation of goals and indicators of research commercialization. We ask why patenting has come to serve as the key policy indicator of innovative capacity and what consequences this has for the organization of academic research. To address these questions, the paper presents a case study from Denmark on, firstly, why and how the 1999 Danish ‘Act on Inventions’ introduced patenting as a central instrument to Danish science policy and, secondly, the effects the Act has had on Danish university organization and research practices. We trace why and how commercialization was introduced as an important objective in Danish science policy since the 1980s. The increased focus on patents is explained as an isomorphic adjustment to an international ‘science policy field,’ manifested in particular through OECD statistics, where patenting has come to serve as a key metric in international rankings. In a second step, we examine what effects the patenting requirements have had on organization and research practice at a Danish university. We show that in practice ‘number of patents’ changed from serving as an indicator of innovative capacity to being a policy goal in itself, thus in effect producing a goal displacement that is potentially damaging for both academic research and innovation capacity of the surrounding society. As a consequence of this goal displacement, active scientists now increasingly engage in patenting primarily as a means to fulfill organizational targets and to increase their ‘fundability,’ rather than to promote commercial applications of their research. In conclusion, we discuss how these unfulfilled policy ambitions have led to a retrospective redefinition of policy goals rather than an adjustment of the actual policy tools.     

Situated Knowledge Production,International Impact: Changing Publishing Practices in a German Engineering Department

In this paper, I analyze how recent calls to internationalize publication behavior affect research practices at an automotive engineering department in Germany. Automotive engineering is a field with traditionally rather scarce publication activity and strong connections to industry. Substantial authority to define suitable research problems and ways of organizing knowledge production on a daily basis was therefore reserved for local academic elites as well as corporate partners. However, as engineers are increasingly expected to prove their performance through publishing in international peer-reviewed journals, the judgment as to what should be considered “interesting” or “robust” research is partly relegated to a gradually globalizing community of academic peers. This generates a variety of tensions with established ways of coordinating epistemic work at the department studied here. For example, the thematic interests of journals tend to exert a disruptive centrifugal pull in the context of an otherwise highly modular research culture, and possibilities to publish in international venues are unequally distributed across individual research projects. But while department members agree that there is a lack of fit between current practices and new expectations towards their publishing behavior, their opinions about the conclusions that should be drawn differ significantly. Some researchers argue that profound organizational changes are necessary to foster the academic rigor of German engineering research. Others believe that evaluation criteria should simply be adapted. This situation is arguably characteristic for research areas with a traditionally strong orientation to local stakeholders, and it suggests a need for more deliberative, participatory approaches to research evaluation in such fields.