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Tuomo Korenius Jorma Laurikkala Martti Juhola Kalervo Järvelin 《Information Retrieval》2006,9(1):33-53
Search facilitated with agglomerative hierarchical clustering methods was studied in a collection of Finnish newspaper articles
(N = 53,893). To allow quick experiments, clustering was applied to a sample (N = 5,000) that was reduced with principal components analysis. The dendrograms were heuristically cut to find an optimal partition,
whose clusters were compared with each of the 30 queries to retrieve the best-matching cluster. The four-level relevance assessment
was collapsed into a binary one by (A) considering all the relevant and (B) only the highly relevant documents relevant, respectively.
Single linkage (SL) was the worst method. It created many tiny clusters, and, consequently, searches enabled with it had high
precision and low recall. The complete linkage (CL), average linkage (AL), and Ward's methods (WM) returned reasonably-sized
clusters typically of 18–32 documents. Their recall (A: 27–52%, B: 50–82%) and precision (A: 83–90%, B: 18–21%) was higher
than and comparable to those of the SL clusters, respectively. The AL and WM clustering had 1–8% better effectiveness than
nearest neighbor searching (NN), and SL and CL were 1–9% less efficient that NN. However, the differences were statistically
insignificant. When evaluated with the liberal assessment A, the results suggest that the AL and WM clustering offer better
retrieval ability than NN. Assessment B renders the AL and WM clustering better than NN, when recall is considered more important
than precision. The results imply that collections in the highly inflectional and agglutinative languages, such as Finnish,
may be clustered as the collections in English, provided that documents are appropriately preprocessed. 相似文献
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Anu Liljeström Jorma Enkenberg Sinikka Pöllänen 《Cultural Studies of Science Education》2013,8(1):51-86
This design experiment aimed to answer the question of how to mediate the practices of authentic science inquiries in primary education. An instructional approach based on activity theory was designed and carried out with multi-age students in a small village school. An open-ended learning task was offered to the older students. Their task was to design and implement instruction about the Ice Age to their younger fellows. The objective was collaborative learning among students, the teacher, and outside domain experts. Mobile phones and GPS technologies were applied as the main technological mediators in the learning process. Technology provided an opportunity to expand the learning environment outside the classroom, including the natural environment. Empirically, the goal was to answer the following questions: What kind of learning project emerged? How did the students’ knowledge develop? What kinds of science learning processes, activities, and practices were represented? Multiple and parallel data were collected to achieve this aim. The data analysis revealed that the learning project both challenged the students to develop explanations for the phenomena and generated high quality conceptual and physical models in question. During the learning project, the roles of the community members were shaped, mixed, and integrated. The teacher also repeatedly evaluated and adjusted her behavior. The confidence of the learners in their abilities raised the quality of their learning outcomes. The findings showed that this instructional approach can not only mediate the kind of authentic practices that scientists apply but also make learning more holistic than it has been. Thus, it can be concluded that nature of the task, the tool-integrated collaborative inquiries in the natural environment, and the multiage setting can make learning whole. 相似文献
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Focused web crawling in the acquisition of comparable corpora 总被引：2，自引：0，他引：2
Tuomas Talvensaari Ari Pirkola Kalervo Järvelin Martti Juhola Jorma Laurikkala 《Information Retrieval》2008,11(5):427-445
Cross-Language Information Retrieval (CLIR) resources, such as dictionaries and parallel corpora, are scarce for special domains.
Obtaining comparable corpora automatically for such domains could be an answer to this problem. The Web, with its vast volumes
of data, offers a natural source for this. We experimented with focused crawling as a means to acquire comparable corpora
in the genomics domain. The acquired corpora were used to statistically translate domain-specific words. The same words were
also translated using a high-quality, but non-genomics-related parallel corpus, which fared considerably worse. We also evaluated
our system with standard information retrieval (IR) experiments, combining statistical translation using the Web corpora with
dictionary-based translation. The results showed improvement over pure dictionary-based translation. Therefore, mining the
Web for comparable corpora seems promising. 相似文献
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Teija Räihä Kerttu Tossavainen Jorma Enkenberg Hannele Turunen 《Technology, Pedagogy and Education》2014,23(2):181-197
This paper presents a study that examined pupils’ views on an ICT-based learning environment in health learning. The study was a part of the wider European Network of Health Promoting Schools programme (ENHPS; since 2008, Schools for Health in Europe, SHE) in Finland, and particularly its sub-project, From Puijo to the World with Health Lunch, which sought to renew secondary schools’ health education by developing and utilising an ICT-based learning environment. The research data were collected through a structured questionnaire presented to pupils (N = 92) in two secondary schools, one rural and one urban, in Eastern Finland. The results showed that pupils’ opinions about the ICT-based learning environment were fairly positive. Pupils felt that the ICT-based learning environment was easy to use and supported cooperative learning. Computing and Internet skills positively supported pupils’ favourable attitudes towards the ICT-based learning environment. An interesting result from the point of view of e-learning was that the pupils increased their awareness of how to critically evaluate health information found on the Internet. 相似文献
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Henriikka Vartiainen Jorma Enkenberg 《Educational technology research and development : ETR & D》2013,61(5):841-862
Sociocultural approaches emphasize the systemic, context-bound nature of learning, which is mediated by other people, physical and conceptual artifacts, and tools. However, current educational systems tend not to approach learning from the systemic perspective, and mostly situate learning within classroom environments. This design-based research aims to seek answers to these challenges by enhancing the use of museum objects and inquiry tools in learning through developing a new kind of virtual environment. By using learning objects that represent physical objects, the students can develop their own research questions, and choose related museum artifacts and inquiry tools with which to find answers to their questions during forthcoming museum visits. This study aims to examine what kinds of learning systems emerged when three different student groups collaboratively designed their visits to the Finnish Forest Museum based on their own interests and afforded resources in the learning environment. Data analysis indicates that a tool-driven system typically seems to represent the approach of primary school students, with an object-driven system for technical college students, and a strategic, research-question-driven system for teacher-education students. When considering the desired effects of technology and open environments on emerging learning systems and processes, the results of the study suggest that self-organization and free choice do not necessarily lead to research-question-driven learning processes, unless the variation in student approaches, design-process scaffolding, and paying attention to the social arrangements, and to the use of tools during the implementation of inquiry activities are all taken into account. 相似文献
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Roles of variables is a new concept that captures tacit expert knowledge in a form that can be taught in introductory programming courses. A role describes some stereotypic use of variables, and only ten roles are needed to cover 99% of all variables in novice-level programs. This paper presents the results of an experiment where roles were introduced to novices learning Pascal programming. Students were divided into three groups that were instructed differently: in the traditional way with no treatment of roles; using roles throughout the course; and using a role-based program animator in addition to using roles in teaching. The results show that students are not only able to understand the role concept and to apply it in new situations but—more importantly—that roles provide students a new conceptual framework that enables them to mentally process program information in a way demonstrating good programming skills. Moreover, the use of the animator seems to foster the adoption of role knowledge. 相似文献
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Markus Nivala Erno Lehtinen Laura Helle Pauliina Kronqvist Jorma Paranko Roger Säljö 《Anatomical sciences education》2013,6(6):361-367
Over the years, the role and extent of the basic sciences in medical curricula have been challenged by research on clinical expertise, clinical teachers, and medical students, as well as by the development and diversification of the medical curricula themselves. The aim of this study was to examine how prior knowledge of basic histology and histopathology among students predicts early learning of diagnostic pathology. Participants (N=118, representing 91% of the full student cohort) were medical students at the University of Turku, Finland. Data were collected during two preclinical courses that students attended in their first and second years of medical school. The measurements included tests on biomedical and clinical knowledge and a performance test in diagnostic pathology. Second‐year performance on the diagnostic pathology examinations was predicted by the students' prior knowledge of histology, but not by the students' prior knowledge of histopathology. Although earlier research has demonstrated similar results in studies with shorter longitudinal designs, the present study demonstrates that the effect remains even if there is a considerably long time delay (a year) between the measurements, thus confirming the long‐term value of basic science studies in the preclinical phase. Anat Sci Educ 6: 361–367. © 2013 American Association of Anatomists. 相似文献
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