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- Lundström, Claes, 1973-, et al.
(författare)
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The alpha-histogram: Using Spatial Coherence to Enhance Histograms and Transfer Function Design
- 2006
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Ingår i: Proceedings Eurographics/IEEE Symposium on Visualization 2006, Lisbon, Portugal. ; , s. 227-234
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The high complexity of Transfer Function (TF) design is a major obstacle to widespread routine use of Direct Volume Rendering, particularly in the case of medical imaging. Both manual and automatic TF design schemes would benefit greatly from a fast and simple method for detection of tissue value ranges. To this end, we introduce the a-histogram, an enhancement that amplifies ranges corresponding to spatially coherent materials. The properties of the a-histogram have been explored for synthetic data sets and then successfully used to detect vessels in 20 Magnetic Resonance angiographies, proving the potential of this approach as a fast and simple technique for histogram enhancement in general and for TF construction in particular.
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| 5. |
- Backman, Ylva, et al.
(författare)
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Ethics in school : from moral development to children's conceptions of justice
- 2009
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Konferensbidrag (refereegranskat)abstract
- A main issue in Swedish school debate is the question of how to teach the student a common value system based on democracy and western humanism. The debate is rather intense, to say the least. Not only is the premise that there exists one value system that we share a target for critique, but there is also the question of what value education is or could be. There is, as well, quite a body of research on children's moral development, where many take as their departure the work of Kohlberg. However, there has been little or no attention on how the individual learner conceptualizes and makes meaning out of ethical issues. That is, descriptions of processes. In this paper we will present what we take to be urgent questions that need to be investigated against the background of prior research and practical work at Södra teatern in Stockholm, Sweden. For eight years in a row, Södra teatern has had as a main project to lead a practice on the subject of philosophy with children. Several groups of youths in the age of nine to eighteen have regularly met to discuss philosophical thoughts and problems, which in a democratic manner are settled for discussion by the participants. Today this philosophical practice has spread to the north of Sweden. In Backman's final exam within the teacher education she has explored the development of children's (7‐8 years old) ability to argue for different ethical positions, both verbally and in writing and painting. This practice has been inspired by the tradition at Södra teatern, but customized to fit a regular school class in Luleå, with very little experience of philosophical discussion. In the very short period of five weeks Backman has been able to see quite significant changes in the children's ability to argue for their ethical positions. The study was initiated by examining some argumentative abilities of the pupils, for instance the ability of expressing an argument for an ethical position in writing. In the final part of the study, the same ability was examined in very similar circumstances, and the augment of expressed arguments in writing was significant. Another consideration that was raised as a consequence of the study regards the pupil's conceptualizing of ethical issues. In some conversations about the notion of justice it became clear that children interpreted the term very differently. This is not very surprising but important to pay further attention to. As mentioned earlier, there has been very little attention on how individual children conceptualize ethical issues. In this paper we argue that more interest should be put on investigating these issues in more depth, and we will do this by an outlining of a research application.
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| 7. |
- Bivall Persson, Petter, 1979-, et al.
(författare)
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Designing and Evaluating a Haptic System for Biomolecular Education
- 2007
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Ingår i: IEEE Virtual Reality Conference, 2007. VR '07.. - Piscataway, NJ, USA : IEEE. - 1424409063 ; , s. 171-178
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Konferensbidrag (refereegranskat)abstract
- In this paper we present an in situ evaluation of a haptic system, with a representative test population, we aim to determine what, if any, benefit haptics can have in a biomolecular education context. We have developed a haptic application for conveying concepts of molecular interactions, specifically in protein-ligand docking. Utilizing a semi-immersive environment with stereo graphics, users are able to manipulate the ligand and feel its interactions in the docking process. The evaluation used cognitive knowledge tests and interviews focused on learning gains. Compared with using time efficiency as the single quality measure this gives a better indication of a system's applicability in an educational environment. Surveys were used to gather opinions and suggestions for improvements. Students do gain from using the application in the learning process but the learning appears to be independent of the addition of haptic feedback. However the addition of force feedback did decrease time requirements and improved the students understanding of the docking process in terms of the forces involved, as is apparent from the students' descriptions of the experience. The students also indicated a number of features which could be improved in future development.
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| 8. |
- Bivall Persson, Petter, 1979-, et al.
(författare)
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Evaluating the Effectiveness of Haptic Visualization in Biomolecular Education - Feeling Molecular Specificity in a Docking Task
- 2006
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Ingår i: 12th IOSTE Symposium. - : Universiti Science Malaysia. - 9832700396 ; , s. 745-752
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Konferensbidrag (refereegranskat)abstract
- Within the molecular life sciences extensive use is made of visual representations, ranging from sketches to advanced computer graphics, often used to convey abstract knowledge that is difficult for the student to grasp. This work evaluates a new visual and haptic (tactile/kinetic) tool for protein docking in an in situ learning situation by combining qualitative and quantitative methods, performing tests and interviews with students; all aiming at a proper inclusion of visualization tools into biomolecular education. Preliminary results indicate time gains, strong positive affective responses and learning gains from the tasks, however the influence of haptics needs further investigation.
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| 9. |
- Bivall Persson, Petter, 1979-, et al.
(författare)
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Improved Feature Detection over Large Force Ranges Using History Dependent Transfer Functions
- 2009
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Ingår i: Third Joint Eurohaptics Conference and Symposium on Haptic Interfaces for Virtual Environments and Teleoperator Systems, WorldHaptics 2009. - : IEEE. - 9781424438587 ; , s. 476-481
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Konferensbidrag (refereegranskat)abstract
- In this paper we present a history dependent transfer function (HDTF) as a possible approach to enable improved haptic feature detection in high dynamic range (HDR) volume data. The HDTF is a multi-dimensional transfer function that uses the recent force history as a selection criterion to switch between transfer functions, thereby adapting to the explored force range. The HDTF has been evaluated using artificial test data and in a realistic application example, with the HDTF applied to haptic protein-ligand docking. Biochemistry experts performed docking tests, and expressed that the HDTF delivers the expected feedback across a large force magnitude range, conveying both weak attractive and strong repulsive protein-ligand interaction forces. Feature detection tests have been performed with positive results, indicating that the HDTF improves the ability of feature detection in HDR volume data as compared to a static transfer function covering the same range.
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