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| 2. |
- Dahl, Ingolf, 1950
(författare)
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How to measure the Mueller matrix of liquid-crystal cells
- 2001
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Ingår i: Meas. Sci. Technol.. - 0957-0233. ; 12, s. 1938-1948
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Tidskriftsartikel (refereegranskat)abstract
- The Mueller matrix is the transfer matrix in the Stokes algebra that describes the polarization of natural light. This matrix is very versatile for the task of characterizing the optical properties of liquid-crystal cells, since it can be used for comparison with theoretical calculations, the determination of material parameters and the modelling of the cell as an optical building block for technological use. We have constructed a Mueller-matrix spectrometer, with the ability to perform fast, dynamic measurements of the Mueller matrix of small areas of liquid-crystal cells throughout the visible range. To illustrate the potential of the instrument, dynamic measurements on a ferroelectric-liquid-crystal cell are presented and analysed. The optical measurements indicate that there is an asymmetry between the up and the down state, tilted smectic layers and polarization reversal initiated at the boundaries.
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| 3. |
- Hansen, Kjetil Falkenberg, 1972-, et al.
(författare)
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Analysis of a genuine scratch performance
- 2004
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Ingår i: Lecture Notes in Computer Science. - Berlin, Heidelberg : Springer Berlin/Heidelberg. - 0302-9743 .- 1611-3349. - 9783540210726 ; 2915, s. 477-478, s. 519-528
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Tidskriftsartikel (refereegranskat)abstract
- The art form of manipulating vinyl records done by disc jockeys (DJs) is called scratching, and has become very popular since its start in the seventies. Since then turntables are commonly used as expressive musical instruments in several musical genres. This phenomenon has had a serious impact on the instrument-making industry, as the sales of turntables and related equipment have boosted. Despite of this, the acoustics of scratching has been barely studied until now. In this paper, we illustrate the complexity of scratching by measuring the gestures of one DJ during a performance. The analysis of these measurements is important to consider in the design of a scratch model.
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| 4. |
- Hansen, Kjetil Falkenberg, 1972-, et al.
(författare)
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DJ scratching performance techniques : Analysis and synthesis
- 2003
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Ingår i: Proc. Stockholm Music Acoustics Conference. ; , s. 693-696
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Konferensbidrag (refereegranskat)abstract
- Scratching is a popular way of making music, turning the DJ into a musician. Normally scratching is done using a vinyl record, a turntable and a mixer. Vinyl manipulation is built up by a number of specialized techniques that have been analysed in a previous study. The present study has two main objectives. First is to better understand and model turntable scratching as performed by DJs. Second is to design a gesture controller for physical sound models, i.e. models of friction sounds. We attached sensors to a DJ equipment set-up. Then a DJ was asked to perform typical scratch gestures both isolated and in a musical context, i.e. as in a real performance. He also was asked to play with different emotions: sad, angry, happy and fearful. A model of the techniques used by the DJ was built based on the analysis of the collected data. The implementation of the model has been done in pd. The Radio Baton, with specially adapted gesture controllers, has been used for controlling the model. The system has been played by professional DJs in concerts.
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| 6. |
- Tollmar, Konrad, et al.
(författare)
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VideoCafe - exploring mediaspaces in public places within organizations
- 2001
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Ingår i: Behavior and Information Technology. - : Informa UK Limited. - 0144-929X .- 1362-3001. ; 20, s. 101-110
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Tidskriftsartikel (refereegranskat)abstract
- This paper describes our studies of mediaspaces which are embedded within public places in organizations so as to examine the hypothesis that individuals might benefit even when working apart - from opportunities for light informal interaction. A set of full-scale prototypes were used and assessed over extensive periods of time. The informal observations and reflection in design of these places have been supplemented by formal studies. We found that great care needs to be taken when designing these places from an architectural point of view. For some of the places, we would like to suggest using architectural features when altering the room rather than technology. In other settings, the artful deployment of communication media might be more effective.
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| 7. |
- Tollmar, Konrad, et al.
(författare)
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Navigating in virtual environments using a vision-based interface
- 2004
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Ingår i: Proceedings of the third Nordic conference on Human-computer interaction. - New York, NY, USA : ACM. - 1581138571 - 9781581138573 ; , s. 113-120
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Konferensbidrag (refereegranskat)abstract
- Interacting and navigating virtual environments usually requires a wired interface, game console, or keyboard. The advent of perceptual interface techniques allows a new option: the passive and untethered sensing of users’ pose and gesture to allow them to maneuver through and manipulate virtual worlds. We describe new algorithms for interacting with 3-D environments using real-time articulated body tracking with standard cameras and personal computers. Our method is based on rigid stereo-motion estimation algorithms and can accurately track upper body pose in real-time. With our tracking system users can navigate virtual environments using 3-D gesture and body poses. We analyze the space of possible perceptual interface abstractions for full-body navigation, and present a prototype system based on these results. We finally describe an initial evaluation of our prototype system with users guiding avatars through a series of 3-D virtual game worlds.
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| 8. |
- Ali, Y, et al.
(författare)
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MedView-design and adoption of an interactive system for oral medicine.
- 2000
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Ingår i: Studies in health technology and informatics. - 0926-9630 .- 1879-8365. ; 77, s. 3-7
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Konferensbidrag (refereegranskat)abstract
- MedView is a joint project with participants from oral medicine and computer science. The aim of the project is to build a large database from patient examinations and produce computerized tools to extend, view, and analyze the contents of the database. The contents of the data base is based on a formalization of health-care processes and clinical knowledge in oral medicine harmonized within the network SOMNET. We give an overview of the current status of the MedView project and discuss background and future directions.
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| 9. |
- Hollmann, Jochen, 1970, et al.
(författare)
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An Evaluation of Document Prefetching in a Distributed Digital Library
- 2003
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Ingår i: Research and AdvancedTechnology for Digital Libraries / Lecture Notes In Computer Science. - Berlin, Heidelberg : Springer Berlin Heidelberg. - 0302-9743 .- 1611-3349. - 9783540407263 ; 2769, s. 276-287
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Latency is a fundamental problem for all distributed systems including digital libraries. To reduce user perceived delays both caching -- keeping accessed objects for future use -- and prefetching -- transferring objects ahead of access time -- can be used. In a previous paper we have reported that caching is not worthwhile for digital libraries due to low re-access frequencies. In this paper we evaluate our previous findings that prefetching can be used instead. To do this we have set up an experimental prefetching proxy which is able to retrieve documents from remote fulltext archives before the user demands them. Using a simple prediction to keep the overhead of unnecessarily transfered data limited, we find that it is possible to cut the user perceived average delay a factor of two.
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| 10. |
- Cappelen, Birgitta, 1962-, et al.
(författare)
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From designing objects to designing fields : from control to freedom
- 2003
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Ingår i: Digital Creativity. - 1462-6268 .- 1744-3806. ; 14:2, s. 74-90
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Tidskriftsartikel (refereegranskat)abstract
- In this paper we want to explore Field as a concept and as a metaphor for understanding interactive systems. By interactive systems we mean both systems and artworks, where the user by interacting changes the course of events. We intend to show why we need new terms and why we consider Field to be a fruitful concept and term. Further we will show how the Field concept changes both our understanding of what we do as designers and composers and how we acknowledge our audience. We will exemplify the design consequences of the Field concept by going through some design considerations we made when designing the audio tactile installation Mufi.
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