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41.
Modeling context through domain ontologies   总被引:1,自引:0,他引:1  
Traditional information retrieval systems aim at satisfying most users for most of their searches, leaving aside the context in which the search takes place. We propose to model two main aspects of context: The themes of the user's information need and the specific data the user is looking for to achieve the task that has motivated his search. Both aspects are modeled by means of ontologies. Documents are semantically indexed according to the context representation and the user accesses information by browsing the ontologies. The model has been applied to a case study that has shown the added value of such a semantic representation of context.
Daniel EgretEmail:
  相似文献   
42.
A survey was conducted to examine the strength of beliefs among French school pupils in three perceptions of the education-labor market link traditionally studied in the economy of human capital: ‘productivity’, ‘screening’ and ‘credentialism’. 247 male and female French students aged between 14 and 24 years responded to a paper-and-pencil questionnaire. The purpose of the study is by means of introducing the concepts of ‘productivity’, ‘screening’ and ‘credentialism’ into the field of psychology of education to identify on the one hand the relative dominance of these three conceptions, and on the other hand to study each in relation to classical demographic variables and psychosocial variables such as academic self-evaluation, self-assessment of the range of vocational options and type of education and training sought by the pupils. Results indicate that students are more inclined to believe that the achievement of academic degrees acts more as a ‘screening’ device and as evidence of achievement than a factor enhancing productivity in the workplace. It seems that the variability of the role assigned to education as regards employability depends on the students' social and academic standing and on the way they deal with it.  相似文献   
43.
This essay explores how nineteenth-century nature study principles inform a twenty-first century New Nature Study movement, and gives examples of a trend toward nature writing in recent picture books. The pedagogical principles of nineteenth-century nature study, ascendant at the turn of the twentieth century and implicit in interwar children’s literature, yielded to a model founded on Cold War competition rather than environmental stewardship. In mid-century narratives for children, technological progress prevailed. In the 1990s, the ideals of the first nature study movement reemerged in a call for meaningful conservation to sustain future generations. Like the original nature study, the New Nature Study arises from anxieties about industrial development, habitat loss and extinction, and hazards to childhood itself. The New Nature Study treats children as agents for change and citizens being denied their full human rights when their land, soil, water, and lives are bought and sold.  相似文献   
44.
Students select majors like supply chain management largely because they want to obtain a high‐paying job at graduation. They expect that after 4 or 5 years of studies, they will be ready to achieve early‐career success. Data, however, reveal that students often are not prepared. Recruiters are noticing. In various studies, employers say that a large majority of graduates are not workplace ready. We argue that this readiness gap results from a mismatch between academia's focus on knowledge transfer and employers’ expectations that new hires possess real competencies. To remedy this readiness gap, we redesigned our curriculum to adopt a deliberate practice pedagogy. What have we learned? Deliberate practice is hard work. Both faculty and students must learn and practice new behaviors. The good news: deliberate practice helps students acquire real expertise that recruiters value. This article makes the case for deliberate practice and outlines a proven path to transformation.  相似文献   
45.
In recent years, plastics are designated as a source of indoor pollution and particular attention has thus been devoted to the identification of emitting low molecular weight compounds. Headspace-solid phase microextraction-gas chromatography coupled with mass spectrometry (HS-SPME-GC/MS) has been already successfully applied for screening emissions from synthetic materials. This analytical tool being also non-invasive, it has been already successfully applied in the field of cultural heritage science for the identification of volatile organic compounds (VOCs) emitted from various museum objects made of natural materials. In this research, we aimed at assessing the use of HS-SPME-GC/MS as an in situ non-invasive analytical tool for a better knowledge of the volatile organic compounds emitted by plastics in collections. The possibility of characterizing plastics based on their emission signatures was also evaluated. Twelve new standard plastic samples, belonging to seven main polymer families widely present in museum collections as well as three naturally aged museum objects, were investigated. In this paper, we provide a survey of the VOCs emitted, and the use of HS-SPME-GC/MS for identifying volatile marker compounds, degradation products, additives, and monomer residues of the plastic synthesis is evaluated. More than 200 different VOCs were identified from the new standard samples. Two categories of VOCs were distinguished: “non-specific” and “specific” ones. We showed that based on the “specific” VOCs, it was possible to identify the nature of the polymeric matrix itself or at least to unambiguously distinguish a plastic by family. Emissions from the museum objects were then characterised, and main volatile degradation compounds considered as degradation markers of the natural deterioration of polymeric matrices, were identified. This identification procedure could be further exploited for the characterization of VOCs emitted by objects made of multiple synthetic polymers. Complementary to other techniques, this analytical tool is an interesting way to assess the risk for the objects stored in the vicinity of emitting plastics.  相似文献   
46.
Abstract

Longitudinal studies provide unique opportunities but are also faced with several limitations. The purpose of this study was to document three of these issues (“imperfect” design, evolution of data collection methods, representativeness) by means of the Leuven Longitudinal Study on Lifestyle, Fitness and Health (LLSLFH). The LLSLFH (1969 – 2004) comprises observations on males between 12 and 18 years and at 30, 35, 40, and 47 years, and on females at 16 and 40 years. In the most recent phase of the study, spouses and offspring were also included. The different phases and evolving research questions throughout the LLSLFH required an appropriate adaptation of the research design. The associated evolution of data collection methods largely reflects the changing ideas about physical fitness, body composition, and physical activity, the continuing search for new and better measurement techniques, and the need for adaptations with age. Ongoing study participants are representative in terms of body composition and, except for adolescence in males, also physical activity. No straightforward answer can be given concerning physical fitness. In both sexes, socio-economic status is above average. When informed about the possible “pitfalls” of longitudinal research in advance, several measures could be taken to prevent or limit them as much as possible.  相似文献   
47.
The transgenic mouse model is useful for studying the causes and potential cures for human genetic diseases. Exposing high school biology students to laboratory experience in developing transgenic animal models is logistically prohibitive. Computer-based simulation, however, offers this potential in addition to advantages of fidelity and reach. This study describes and evaluates a computer-based simulation to train advanced placement high school science students in laboratory protocols, a transgenic mouse model was produced. A simulation module on preparing a gene construct in the molecular biology lab was evaluated using a randomized clinical control design with advanced placement high school biology students in Mercedes, Texas (n?=?44). Pre-post tests assessed procedural and declarative knowledge, time on task, attitudes toward computers for learning and towards science careers. Students who used the simulation increased their procedural and declarative knowledge regarding molecular biology compared to those in the control condition (both p?<?0.005). Significant increases continued to occur with additional use of the simulation (p?<?0.001). Students in the treatment group became more positive toward using computers for learning (p?<?0.001). The simulation did not significantly affect attitudes toward science in general. Computer simulation of complex transgenic protocols have potential to provide a ??virtual?? laboratory experience as an adjunct to conventional educational approaches.  相似文献   
48.
This study investigated the prospective links between sleep in infancy and preschoolers' cognitive performance. Mothers of 65 infants completed a sleep diary when infants were aged 1 year, and children completed two subscales of the Wechsler Preschool and Primary Scale of Intelligence at 4 years, indexing general cognitive ability and complex executive functioning. Consistent with hypotheses, children getting higher proportions of their sleep at night as infants were found to perform better on executive functions, but did not show better general cognition. Relations held after controlling for family socioeconomic status and prior cognitive functioning. These findings suggest that the special importance of sleep for higher order cognition, documented among adults, may appear very early in life.  相似文献   
49.
In this article, we present the results from a mixed-methods research study aimed to document indoor and outdoor fifth grade science experiences in one school in the USA in the context of accountability and standardized testing. We used quantitative measures to explore students’ science knowledge, environmental attitudes, and outdoor comfort levels, and via qualitative measures, we examined views on science education and environmental issues from multiple sources, including the school’s principal, teachers, and students. Students’ science knowledge in each of the four objectives specified for grade 5 significantly improved during the school year. Qualitative data collected through interviews and observations found limited impressions of outdoor science. Findings revealed that, despite best intentions and a school culture that supported outdoor learning, it was very difficult in practice for teachers to supplement their classroom science instruction with outdoor activities. They felt constrained by time and heavy content demands and decided that the most efficient way of delivering science instruction was through traditional methods. Researchers discuss potentials and obstacles for the science community to consider in supporting teachers and preparing elementary school teachers to provide students with authentic experiential learning opportunities. We further confront teachers’ and students’ perceptions that science is always best and most efficiently learned inside the classroom through traditional text-driven instruction.  相似文献   
50.
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