Softwareentwicklung in der Medizintechnik am Beispiel der medizinischen Bildverarbeitung

Zusammenfassung  Dieser Beitrag gibt einen überblick über unterschiedliche Bildgebungs- und Bildverarbeitungsverfahren, die heute in den Kliniken verwendet werden. Es wird die gesamte Bildkette von der Bildverarbeitung über die Bildverbesserung bis hin zur Rekonstruktion und Bildregistrierung beschrieben. Die einzelnen Themenkomplexe werden dabei aus medizinischer und technischer Sicht diskutiert. Aus den klinischen Anforderungen und den gesetzlichen Randbedingungen folgen wichtige Grunds?tze für die Architekturkonzepte und den Entwicklungsprozess medizinischer Bildverarbeitungssysteme. CR subject classification  I.4.3; I.4.5; I.4.6; I.5.5     

Reconceptualizing the paradox of openness: How solvers navigate sharing-protecting tensions in crowdsourcing

The paradox of openness describes the fundamental tension between knowledge sharing and knowledge protection in open innovation. While sharing is vital for value creation, protecting is critical for value appropriation. Prior research has examined this paradox of openness from the perspective of the seeking firm, focusing on the firm-level challenges of inbound open innovation. In this article, we complement that research by illuminating the tensions between sharing and protecting in individual-level outbound open innovation, where we argue that the paradox of openness is most prevalent, yet much less well understood. Drawing on the experience of individual participants, or solvers, in intermediated crowdsourcing contests, we analyze textual data from 2,149 answers to five open-ended narrative questions embedded in a large-scale solver survey, as well as 43 in-depth interviews of solvers. Our findings indicate that individual solvers face fundamental sharing-protecting tensions that carry considerable economic and psychological costs. We also document how solvers attempt to navigate the paradox of openness by employing three formal and four informal value appropriation practices. They build elaborate configurations of these practices, which they tailor to the idiosyncrasies of each contest. They also dynamically adjust these configurations over time, as the contest and the interaction with the seeker unfold. We end by outlining how these findings contribute to a more multifaceted conceptualization and a richer understanding of the paradox of openness.     

Problems of securing equal access to higher education: The dilemma between equality and excellence

In the last few years higher education has undergone a thorough reassessment. In the classical liberal philosophy of equality of opportunity, education was regarded as the chief instrument for bringing about equality of life chances. Free access to further education and the provision of more places with the purpose of increasing participation were conceived as the main policy instruments for achieving equality of opportunity. Nevertheless, imbalances between social strata tended to remain in spite of increased participation. Research has contributed to increased sophistication and the realisation of a series of equalisation incompatibilities.The formal education system exists to impart competence considered to be of value both to the individual and society. Some enter the system better equipped than others, initial differences tend to increase instead of being levelled out. At the core of any admissions policy are the criteria of access. Cognitive differences account for only half or less of differences in educational attainments. Attitudes, aspirations and motivation are also of importance and explain a large portion of the social imbalances that remain after the removal of more tangible factors. Different combinations of criteria in varying degrees achieve equality of access.The question is raised whether in a mass system of higher education one would have to consider a dual admissions procedure to preserve the academic core system, i.e. graduate studies and research.Invited address to the Third International Conference on Higher Education, University of Lancaster, England, September, 1975.     

To Score or Not to Score: Factors Influencing Performance and Feasibility of Automatic Content Scoring of Text Responses

In this article, we systematize the factors influencing performance and feasibility of automatic content scoring methods for short text responses. We argue that performance (i.e., how well an automatic system agrees with human judgments) mainly depends on the linguistic variance seen in the responses and that this variance is indirectly influenced by other factors such as target population or input modality. Extending previous work, we distinguish conceptual, realization, and nonconformity variance, which are differentially impacted by the various factors. While conceptual variance relates to different concepts embedded in the text responses, realization variance refers to their diverse manifestation through natural language. Nonconformity variance is added by aberrant response behavior. Furthermore, besides its performance, the feasibility of using an automatic scoring system depends on external factors, such as ethical or computational constraints, which influence whether a system with a given performance is accepted by stakeholders. Our work provides (i) a framework for assessment practitioners to decide a priori whether automatic content scoring can be successfully applied in a given setup as well as (ii) new empirical findings and the integration of empirical findings from the literature on factors that influence automatic systems' performance.     

Discovery learning of object-oriented modelling with exploration modules in secondary Informatics education

Discovery learning is very desirable not only in secondary education, because it prepares learners for life-long learning. Within secondary Informatics education in Germany, pupils often acquire many concepts by learning to program. To be able to model, to design and to evaluate own solutions, learners must acquire many details of a programming language and apply complex software development environments. So a lot of time gets lost for important topics, like the working principles of Informatics systems. The research presented here focuses on learning by exploration instead. The basic idea is that before developing own (typically small) solutions, learners explore medium size solutions by means of special learner-adequate Informatics systems, named exploration modules (EMs) here. In this paper, the author presents important aspects of the development methodology of such software, its application to the educational field of object-oriented modelling and shows how EM prototypes have successfully been included in different learning scenarios of secondary Informatics education, Informatics teacher education, and in-service Informatics teacher training within the academic years 2001 to 2004.