算法谜题

正出版社:人民邮电出版社出版时间:2014-03-01ISBN:9787115338440所属分类:图书计算机与互联网操作系统算法是计算机科学领域最重要的基石之一。算法谜题,就是能够直接或间接地采用算法来加以解决的谜题。求解算法谜题是培养和锻炼算法思维能力一种最有效和最有乐趣的途径。《算法谜题》是一本经典算法谜题的合集。书中包括了一些古已有之的谜题,数学和计算机科学有一部分知识就发源于此。《算法谜题》中还有一些较新的谜题,其中有一部分谜题     

Critical factors influencing secondary school pupil’s decisions to study computing in tertiary education: Gender differences

This paper aims to determine the factors affecting the decisions of both male and female secondary school pupils whether or not to pursue undergraduate studies in Computing. It is based on research conducted in Greece, on a sample of 248 pupils, 135 of whom were female. All were aged 17 and about to decide on their future undergraduate studies. Questionnaires were used, addressing issues in the following four main categories: a) the reasons pupils chose/rejected Computing, b) how family and friends, the media and the school environment contribute to their decision, c) how pupils perceived their future after studying Computing and d) how pupils perceived the profile of a computer professional in terms of gender.

Psychometric evaluation of the exercise identity scale among Greek adults and cross-cultural validity

The present study reported on translating the Exercise Identity Scale (EIS: Anderson & Cychosz, 1994) into Greek and examining its psychometric properties and cross-cultural validity based on U.S. individuals' EIS responses. Using four samples comprising 33, 103, and 647 Greek individuals, including exercisers and nonexercisers, and a similar sample comprising 800 U.S. individuals, the concurrent validity, factor structure, internal reliability, test-retest reliability, external validity, gender invariance, and cross-cultural validity of the EIS responses were examined using confirmatory factor analytical procedures. The results supported the concurrent validity, an adequate unidimensional factor structure for the translated EIS and the internal reliability and test-retest reliability over a 6-week interval. Further, cross-gender configural, partial metric, partial strong factorial, and partial strict factorial invariance and cross-cultural configural and partial metric invariance supported the cross-cultural equivalence of the EIS versions. Moreover, the external validity of the translated EIS responses was also supported. Overall, the findings supported the validity of the exercise identity construct outside North American boundaries and the EIS items' equivalence, providing initial evidence for its cross-cultural applicability.     

Meeting players where they are: Digital games and learning ecologies

This paper explores the relationship between digital games and learning along the continuum from formal to informal learning. Games are an increasingly important component of our learning ecologies but their potential can prove difficult to fully harness due to the downsides of gaming in informal contexts and to the limitations games can present when adopted in formal learning contexts. The aim of this paper is to shed light on the strengths and weaknesses of games for learning, and to gather stakeholder recommendations for the main actors in the field. The adopted research approach is qualitative and participatory, involving players, teachers, parents, researchers and developers. Data from 25 interviews and 11 focus groups yielded insights into the educational, psychological and ethical aspects of play. Results suggest that gameplay influences individuals in a very personal manner, and that its effects cover a wide range of skills, extending to identity development. Hence, to harness this potential, all actors in the ecology need strong awareness of both the affordances and the risks of games, and deep respect for individuals’ LEs. The study has implications for a wide range of actors, including educators, players, researchers, parents, game developers and policymakers.     

Does sensorimotor training improve the static balance of young volleyball players?

The aim of this investigation is to assess the effectiveness of a 6-week balance training (BT) protocol, integrated in regular training sessions, on postural sway of young female volleyball players (n = 26, age 13.0 +/- 0.2 years) divided into two groups (intervention and control; 13 per group). Trials were performed for bipedal and unipedal stance conditions before and after the BT protocol, using a pressure platform to collect center-of-pressure (COP) time series that were processed to calculate sway area, COP path length, and maximum displacement range in anteroposterior and mediolateral directions. The intervention group exhibited smaller sway areas in eyes closed conditions (intervention = 42.76 mm2, control = 67.60 mm2; p < 0.05) and Romberg quotients (intervention = 1.11 mm, control = 1.82 mm) in bipedal stance, while all the other parameters were unaffected. BT also reduced sway area (intervention = 122.70 mm2, control = 187.18 mm2) and anteroposterior COP displacements (intervention = 20.18 mm, control = 22.38 mm) of the non-dominant limb for single-leg stance. No significant change was found for the dominant limb. Although it is possible to hypothesize a beneficial effect of BT on young athletes, further investigations are required to clarify its actual effect on balance performance with respect to normal volleyball training.     

Online Teacher Training in a Context of Forced Immobility: The Case of Gaza,Palestine

This article discusses an action research study that involved the design and delivery of an online training course for teachers of Arabic to speakers of other languages in the Gaza Strip (Palestine). Grounded in Freirean pedagogy, the course aimed to respond to the employment needs of university graduates by creating opportunities for online language teaching. The action research study explored the dynamics at play within the online educational environment, to evidence elements that challenged and/or facilitated effective collaboration between trainers and trainees. This article retraces and discusses the processes through which the course moved from didacticism to engaged critical pedagogy.     

La Medusa by Caravaggio: characterisation of the painting technique and evaluation of the state of conservation

The oil painting “La Medusa” executed by Caravaggio at the end of the XVI century on a wooden shield, was investigated by integrated physical–chemical and analytical methodologies in order to obtain scientific data capable of elucidating the state of conservation and the painting technique. Optical (OM) and electronic (SEM-EDS) microscopy, micro-FT-IR spectroscopy, gas chromatography–mass spectrometry (GC–MS) and pyrolysis GC–MS were applied on two microfragments and some organic samples obtained by solvent extraction using the swab cleaning technique. The obtained results indicated that Caravaggio probably reused an old shield as a previous gypsum preparation layer has been detected under the original painting layers. He used white lead, natural earths, verdigris and lead–tin yellow type I mixed with drying oils to paint. The considerable amount of amorphous particles of copper chlorides found in the green pigment verdigris suggests that it could have been produced according to the ancient recipe of verde salsum described by Theophilus. Mordant gilding has been identified on the upper part of the shield that can be related to an abandoned experiment to give the painting a mirror-like reflecting effect. Three different varnishes layers have been detected above the painted surface. The original and restoration varnishes have been identified and they contain a mixture of drying oil, mastic and turpentine and some beeswax. Cleaning tests, performed with different organic solvents, suggest the use of isopropyl alcohol as cleaning agent because it is less efficient in comparison to others solvents; thus it ensures a careful and controlled removal of the varnishes.     

Development of letter position processing: effects of age and orthographic transparency

This study investigated the relative extent to which developing readers (6‐ and 9‐year‐olds) of English (deep) or Greek (transparent) orthography exhibit serial and exterior letter effects in letter position encoding. Participants were given a visual search task that required detection of a pre‐specified target letter within a random five‐letter string. Stimuli comprised letters either specific to English or Greek, or shared by both orthographies. For native letters, all readers showed significant initial‐letter facilitation. In contrast, final‐letter facilitation was shown only by English children. Furthermore, Greek 9‐year‐olds showed significantly more left‐to‐right facilitation than English 9‐year‐olds. These results suggest that letter position encoding is adaptive to the nature of the orthography acquired during reading development.     

The use of portfolios to foster professionalism: attributes,outcomes, and recommendations

The main objective of this research was to review the characteristics of portfolios and their outcomes for teaching professionalism to undergraduate medical students. A systematic review on the use of portfolios in teaching professionalism to medical students identified 1257 papers. Of these, 11 articles met all inclusion criteria. According to the papers, the use of portfolios for teaching professionalism shows versatility, supports learning strategies and has the potential to be used in different contexts, including for formative and summative purposes. The weaknesses were based on the artificiality of the reflections, deficient instructions, time-consuming processes and preference among students for other teaching methods. Students complained about feeling that the reflection was ‘forced’, and they tended to write based on social conventions rather than reveal their true thoughts. Reflection is a powerful component of the portfolio, but the method by which it is taught could easily ruin its potential to boost professionalism. Requiring reflection did not ensure its achievement; increased understanding by students regarding how and why they were doing it, the clarity of assessment methods and constructive feedback might strengthen the potential for success. A framework was designed to support faculty members in developing and applying portfolios with a clear and broad view of this teaching strategy.