User community vs. producer innovation development efficiency: A first empirical study     

Christoph Hienerth  Eric von Hippel  Morten Berg Jensen 《Research Policy》2014

In this paper we report upon a first empirical exploration of the relative efficiency of innovation development by product users vs. product producers. In a study of over 50 years of product innovation in the whitewater kayaking field, we find users in aggregate were approximately 3× more efficient at developing important kayaking product innovations than were producers in aggregate. We speculate that this result is driven by what we term “efficiencies of scope” in problem-solving. These can favor an aggregation of many user innovators, each spending a little, over fewer producer innovators benefitting from higher economies of scale in product development. We also note that the present study explores only one initial point on what is likely to be a complex efficiency landscape.  相似文献   

Unsteady flow phenomena in human undulatory swimming: a numerical approach     

Steffen Pacholak  Stefan Hochstein  Alexander Rudert  Christoph Brücker 《Sports biomechanics / International Society of Biomechanics in Sports》2014,13(2):176-194

The undulatory underwater sequence is one of the most important phases in competitive swimming. An understanding of the recurrent vortex dynamics around the human body and their generation could therefore be used to improve swimming techniques. In order to produce a dynamic model, we applied human joint kinematics to three-dimensional (3D) body scans of a female swimmer. The flow around this dynamic model was then calculated using computational fluid dynamics with the aid of moving 3D meshes. Evaluation of the numerical results delivered by the various motion cycles identified characteristic vortex structures for each of the cycles, which exhibited increasing intensity and drag influence. At maximum thrust, drag forces appear to be 12 times higher than those of a passive gliding swimmer. As far as we know, this is the first disclosure of vortex rings merging into vortex tubes in the wake after vortex recapturing. All unsteady structures were visualized using a modified Q-criterion also incorporated into our methods. At the very least, our approach is likely to be suited to further studies examining swimmers engaging in undulatory swimming during training or competition.  相似文献   

Development of a didactical training concept for peer tutors in gross anatomy          下载免费PDF全文

Simone Alvarez  Christoph Nikendei  Jobst‐Hendrik Schultz 《Anatomical sciences education》2017,10(5):495-502

Even though peer tutors are often used in gross anatomy courses, research in the field is rather a subject of the last two decades. This is especially true about the didactical challenges these types of peer tutors experience during their tutorials and about how they are prepared for the task. The aim of the presented study was to learn about the training needs of the tutors, and to subsequently design, implement, and evaluate a didactical training concept. A qualitative design was chosen to examine how tutors can best be prepared for tutorials of gross anatomy. To do so, focus group interviews were conducted. The data were analyzed and grouped into various concepts, using semi‐structured interview questions as guidance. It was found that peer tutors are in need of training in the following aspects: Dealing with students who are experiencing difficulties during or as a result of dissection, dealing with group dynamics, that is, at the dissection table, keeping students motivated, time management, and staying confident as a tutor. In order to be regarded as useful and relevant in the eyes of tutors, a preparatory training course should include all these aspects in addition to general didactical training elements. Training needs of peer tutors of gross anatomy go beyond the content of standardized didactical curricula; therefore, tutors should be prepared with a curriculum that is specifically geared toward the many challenges associated with teaching gross anatomy to first year medical students which are already so well documented in the research literature. Anat Sci Educ 10: 495–502. © 2017 American Association of Anatomists.  相似文献   

Ethical issues of online communication research     

Rafael Capurro  Christoph Pingel 《Ethics and Information Technology》2002,4(3):189-194

The paper addresses severalethical issues in online communication researchin light of digital ontology as well as theepistemological questions raised by theblurring boundary between fact and theory inthis field. The concept of ontology is used ina Heideggerian sense as related to the humancapacity of world construction on the basis ofthe givenness of our being-in-the-world.Ethical dilemmas of Internet research thusarise from the tension between bodily existenceand the proper object of research, i.e., onlineexistence. The following issues are beingconsidered: online identity, online language,online consent and confidentiality. We alsoargue that research ethics in the US followsthe utilitarian tradition, while Europeanresearchers are deontologically oriented. Aguideline of best practice in online researchethics is proposed.  相似文献   

A comparison of anthropometric and training characteristics of Ironman triathletes and Triple Iron ultra-triathletes     

Knechtle B  Knechtle P  Rüst CA  Rosemann T 《Journal of sports sciences》2011,29(13):1373-1380

We examined differences in anthropometry and training between 64 Triple Iron ultra-triathletes competing over 11.4 km swimming, 540 km cycling, and 126.6 km running, and 71 Ironman triathletes competing over 3.8 km swimming, 180 km cycling, and 42.2 km running. The association of anthropometry and training with race time was investigated using multiple linear regression analysis. The Triple Iron ultra-triathletes were smaller (P < 0.05), had shorter limbs (P < 0.05), a higher body mass index (P < 0.05), and larger limb circumferences (P < 0.01) than the Ironman triathletes. The Triple Iron ultra-triathletes trained for more hours (P < 0.01) and covered more kilometres (P < 0.01), but speed in running during training was slower compared with the Ironman triathletes (P < 0.01). For Triple Iron ultra-triathletes, percent body fat (P = 0.022), training volume per week (P < 0.0001), and weekly kilometres in both cycling (P < 0.0001) and running (P < 0.0001) were related to race time. For Ironman triathletes, percent body fat (P < 0.0001), circumference of upper arm (P = 0.006), and speed in cycling training (P = 0.012) were associated with total race time. We conclude that both Triple Iron ultra-triathletes and Ironman triathletes appeared to profit from low body fat. Triple Iron ultra-triathletes relied more on training volume in cycling and running, whereas speed in cycling training was related to race time in Ironman triathletes.  相似文献   

D ‐‐ Federal Republic of Germany     

Christoph Kodron 《欧洲师范教育杂志》1994,17(1-2):61-64

  相似文献   

COBRA Cooperation within Bureau Research and Administration     

Utz Osterfeld  Christoph Hornung 《Informatik - Forschung und Entwicklung》1995,10(4):216-219

  相似文献   

A faster running speed is associated with a greater body weight loss in 100-km ultra-marathoners     

Knechtle B  Knechtle P  Wirth A  Alexander Rüst C  Rosemann T 《Journal of sports sciences》2012,30(11):1131-1140

In 219 recreational male runners, we investigated changes in body mass, total body water, haematocrit, plasma sodium concentration ([Na(+)]), and urine specific gravity as well as fluid intake during a 100-km ultra-marathon. The athletes lost 1.9 kg (s = 1.4) of body mass, equal to 2.5% (s = 1.8) of body mass (P < 0.001), 0.7 kg (s = 1.0) of predicted skeletal muscle mass (P < 0.001), 0.2 kg (s = 1.3) of predicted fat mass (P < 0.05), and 0.9 L (s = 1.6) of predicted total body water (P < 0.001). Haematocrit decreased (P < 0.001), urine specific gravity (P < 0.001), plasma volume (P < 0.05), and plasma [Na(+)] (P < 0.05) all increased. Change in body mass was related to running speed (r = -0.16, P < 0.05), change in plasma volume was associated with change in plasma [Na(+)] (r = -0.28, P < 0.0001), and change in body mass was related to both change in plasma [Na(+)] (r = -0.36) and change in plasma volume (r = 0.31) (P < 0.0001). The athletes consumed 0.65 L (s = 0.27) fluid per hour. Fluid intake was related to both running speed (r = 0.42, P < 0.0001) and change in body mass (r = 0.23, P = 0.0006), but not post-race plasma [Na(+)] or change in plasma [Na(+)] (P > 0.05). In conclusion, faster runners lost more body mass, runners lost more body mass when they drank less fluid, and faster runners drank more fluid than slower runners.  相似文献   

Knowledge Orientations of Prospective Early Childhood Teachers: A Study of Students' Scientific Versus Subjective Orientations in Teacher Education Courses in Germany     

Christoph Mischo  Stefan Wahl  Janina Strohmer  Jessica Hendler 《Journal of Early Childhood Teacher Education》2013,34(2):144-162

Recent changes in the system of early childhood teacher education in Germany raise the question of whether different academic levels of early childhood teacher education lead to different beliefs and orientations. In this study, prospective early childhood teachers' orientations to scientific knowledge and to research were explored. A questionnaire addressing orientations to the utility of research, educational and psychological theories versus orientations to intuitive theories and personal experience was completed by 712 prospective early childhood teachers. In a latent profile analysis, two types of orientation profiles could be identified: (a) an orientation towards subjective theories, lay theories, and subjective experience, and (b) an orientation towards scientific theories and research results. Results are discussed from the perspective of professionalization in early childhood teacher education.  相似文献   

No public value without a valued public     

Bettina Lis  Heinz-Werner Nienstedt  Christoph Günster 《媒体管理杂志》2018,20(1):25-50

This study aims to enlighten the controversial discussion about the term public value in an innovative way. Instead of normative pronouncements and paternalistic posits, this study combines a theoretical, literature-based conception with an empirical quantitative approach. For this, the key term, public value, is split into its constituent parts of customer value and citizen value and is transformed into measurable attributes. By means of a choice-based conjoint analysis on panel data for Germany and the United Kingdom, we explore which performance attributes of public service broadcasters are the most important. Based on the results, we create a conception of public value from the perspective of the license fee payers as the main stakeholder of public service broadcasters. Our findings may unlock existing potential to increase our understanding of what is meant by the term public value.  相似文献