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Filippos Giannakas Georgios Kambourakis Andreas Papasalouros Stefanos Gritzalis 《Educational technology research and development : ETR & D》2018,66(2):341-384
With the increasing popularity of smartphones and tablets, game-based learning (GBL) is undergoing a rapid shift to mobile platforms. This transformation is driven by mobility, wireless interfaces, and built-in sensors that these smart devices offer in order to enable blended and context-sensitive mobile learning (m-Learning) activities. Thus, m-Learning is becoming more independent and ubiquitous (u-Learning). In order to identify and analyze the main trends and the future challenging issues involved in designing mGBL learning strategies, as well as to bring to the foreground important issues pertaining to mobile and context-aware ubiquitous GBL, the work at hand conducts a comprehensive survey of this particular area. Specifically, it introduces and applies a six-dimensional framework consisted of Spatio-temporal, Collaboration/Social, Session, Personalization, Data security & privacy, and Pedagogy, with the aim of scrutinizing the contributions in the field of mGBL published from 2004 to 2016. It was found that the transition to mGBL presents several difficulties, and therefore cannot be conceived as a simple and quick modification of existing GBL solutions. In this respect, this work is anticipated to foster the development of well-designed solutions that are intensive not only in their technological aspect, but in pedagogical qualities as well. 相似文献
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Athanasios Kabasakalis Stefanos Nikolaidis George Tsalis Kosmas Christoulas Vassilis Mougios 《Journal of sports sciences》2019,37(7):827-832
Irisin and redox status markers seem to share common pathways of exercise-induced upregulation. The aim of the present study was to assess the effects of sprint interval swimming exercise dose and sex on the circulating levels of irisin and redox status markers in adolescent swimmers. Sixteen male and 16 female adolescent swimmers completed two sets of 4 × 50 m maximal freestyle swimming with a send-off time of 90 s, separated by 10 min of passive recovery. Venous blood samples were obtained pre-exercise (Pre), after the first set (Post1) and after the second set (Post2). Males had higher irisin levels than females. Reduced glutathione (GSH, μmol g Hb?1) increased from 8.6 (2.2) [pooled males and females, mean (SD) throughout] at Pre to 9.4 (2.1) at Post1 and Post2. Total antioxidant capacity (μmol DPPH mL?1) increased from 0.89 (0.17) at Post1 to 0.94 (0.16) at Post2. 8-hydroxy-2´-deoxyguanosine (ng mL?1) increased from 20.9 (6.9) at Pre and 21.5 (7.1) at Post1 to 25.0 (10.9) at Post2. Overall, sprint interval swimming exercise induced small but potentially effective changes in the studied parameters. Exercise dose influenced the GSH and 8-OHdG responses, and sex affected irisin levels. 相似文献
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P.N. Paraskevopoulos 《Journal of The Franklin Institute》1979,308(5):475-486
This paper considers the problem of matching the transfer function matrix of a given two-dimensional (2-D) system to that of a desired 2-D model using state feedback. The approach followed refers to systems having square transfer function matrices and reduces the problem to that of solving a linear system of equations. Furthermore, necessary and sufficient conditions are established for exact matching. An example is included to illustrate the proposed method. 相似文献
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The conventional modal control theory is concerned with the problem of determining a state feedback matrix-valued gain which drives the system eigenvalues to prescribed positions. When the parameters of the open-loop system involve certain variations, the closed-loop eigenvalues, obtained by using a feedback gain determined as above, also contain variations. In the present paper the problem of choosing an additional state feedback gain such as to reduce the closed-loop eigenvalue variations as much as desired is solved. Specifically, upon the assumption that a nominal set of parameter values is given, and that a feedback modal control law which drives the eigenvalues of the nominal closed-loop system to the desired positions is known, two alternative expressions for the required additional reduced eigenvalue sensitivity feedback controller are derived. Both cases of known and unknown system state vector are considered. The theory is illustrated by several examples. 相似文献
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Volianitis S Dawson EA Dalsgaard M Yoshiga C Clemmesen J Secher NH Olsen N Nielsen HB 《Journal of sports sciences》2012,30(2):149-153
Reduced hepatic lactate elimination initiates blood lactate accumulation during incremental exercise. In this study, we wished to determine whether renal lactate elimination contributes to the initiation of blood lactate accumulation. The renal arterial-to-venous (a-v) lactate difference was determined in nine men during sodium lactate infusion to enhance the evaluation (0.5 mol x L(-1) at 16 ± 1 mL x min(-1); mean ± s) both at rest and during cycling exercise (heart rate 139 ± 5 beats x min(-1)). The renal release of erythropoietin was used to detect kidney tissue ischaemia. At rest, the a-v O(2) (CaO(2)-CvO(2)) and lactate concentration differences were 0.8 ± 0.2 and 0.02 ± 0.02 mmol x L(-1), respectively. During exercise, arterial lactate and CaO(2)-CvO(2) increased to 7.1 ± 1.1 and 2.6 ± 0.8 mmol x L(-1), respectively (P < 0.05), indicating a -70% reduction of renal blood flow with no significant change in the renal venous erythropoietin concentration (0.8 ± 1.4 U x L(-1)). The a-v lactate concentration difference increased to 0.5 ± 0.8 mmol x L(-1), indicating similar lactate elimination as at rest. In conclusion, a -70% reduction in renal blood flow does not provoke critical renal ischaemia, and renal lactate elimination is maintained. Thus, kidney lactate elimination is unlikely to contribute to the initial blood lactate accumulation during progressive exercise. 相似文献
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Manolis Wallace Kostas Karpouzis Mary Stefanou Ilias Maglogiannis Stefanos Kollias 《Education and Information Technologies》2004,9(3):271-289
The new educational approaches, as far as teaching of history in secondary education is concerned, are characterized by a shift away from sterile memorization and towards a critical approach of historical facts and phenomena; the aim is to contribute to both the development of students' historical concept and conscience and the promotion of critical thought. These teaching goals are pursued by promoting initiative of the students through self study assignments in the form of projects; students can be greatly supported in such tasks by computer-based applications, which can offer access to vast amounts of historical texts and data to be used next to the main scholar textbook and be analyzed by students. Still, existing applications seem to be quite inadequate for this purpose, as they require that the student be already informed on a matter, before the initiation of a quest for data. In this paper, we describe an intelligent information system that is designed to facilitate browsing of educational material and historical sources, thus allowing students to efficiently retrieve information on topics that are not yet known to them and expand in this way their historical knowledge. This can help in fulfilling the aforementioned teaching goals. Our system relies on the notion of the Electronic Road. 相似文献
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V. Ganitis E. Pavlidou F. Zorba K.M. Paraskevopoulos D. Bikiaris 《Journal of Cultural Heritage》2004,5(4):349-360
The pigments, organic materials and techniques used on a post-Byzantine icon of St Nicholas were determined by means of several micro-analytical techniques. The icon painter covered the leather support with silver leaf about 3 μm thick to create a smooth working surface. Animal glue was used to secure the leaf to the leather, and FTIR spectroscopy has identified another layer, 30–60 μm thick, of the same material applied as a primer above the silver. Above that, a layer of lead white covering the entire surface creates a white substratum serving the same purpose as the gesso on a wood panel. The colour palette, determined by means of scanning electron microscopy and FTIR spectroscopy, is very simple. Only seven colours were identified: lead white, caput mortuum, red and yellow ochre, cinnabar, carbon black and smalt. As far as we know, this is the first time that smalt has been found on a Byzantine icon. Since smalt was chemically synthesised only after 1500 AD, it may be concluded that this icon was painted after the end of the 15th century. Beeswax was used as a protective varnish. 相似文献
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Stefanos Karamaroudis Eleni Poulogiannopoulou Marinos G. Sotiropoulos Thomas Kalantzis Elizabeth O. Johnson 《Anatomical sciences education》2020,13(6):694-706
In light of the current shifts in medical education from traditional lectures to more active teaching modalities, a peer-teaching program was introduced to a compulsory, second-year neuroanatomy course. A cross-sectional survey of 527 medical students in the six-year medical program of the National and Kapodistrian University of Athens was administered. The primary aim of the survey, which was distributed to second- through sixth-year medical students, who had completed the neuroanatomy course, was to assess student perception of peer teachers (PTs). Across the five years assessed, students increasingly acknowledged the contribution of PTs to their learning (P < 0.001). Attributes of PTs (e.g., contribution to learning, motivation, effective usage of material, and team environment) were significantly related to the student's opinion of the importance of laboratory activities (P < 0.001). Students who received “average” final grades scored the importance of laboratory exercises, and by inference PTs, significantly lower than students who received “excellent” final grades (P < 0.05). The amount of training that PTs had received was also significantly related to student perceptions of a PT's contribution. Better trained PTs were associated with significantly higher scores regarding learning, motivation, and positive environment compared to less trained PTs (P < 0.05). The results of the present study show that peer-teaching was well received by students attending the neuroanatomy course. While the results express the evolution of the program across the years, the findings also show that learners believed that PTs and the laboratory program contributed significantly to their understanding of neuroanatomy. 相似文献
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