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- Andersson Ersman, Peter, et al.
(author)
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Integration of Screen Printed Piezoelectric Sensors for Force Impact Sensing in Smart Multifunctional Glass Applications
- 2022
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In: Advanced Engineering Materials. - : John Wiley & Sons, Ltd. - 1438-1656 .- 1527-2648. ; 24:11
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Journal article (peer-reviewed)abstract
- Screen printed piezoelectric polyvinylidene fluoride?trifluoro ethylene (PVDF?TrFE)-based sensors laminated between glass panes in the temperature range 80?110?°C are presented. No degradation of the piezoelectric signals is observed for the sensors laminated at 110?°C, despite approaching the Curie temperature of the piezoelectric material. The piezoelectric sensors, here monitoring force impact in smart glass applications, are characterized by using a calibrated impact hammer system and standardized impact situations. Stand-alone piezoelectric sensors and piezoelectric sensors integrated on poly(methyl methacrylate) are also evaluated. The piezoelectric constants obtained from the measurements of the nonintegrated piezoelectric sensors are in good agreement with the literature. The piezoelectric sensor response is measured by using either physical electrical contacts between the piezoelectric sensors and the readout electronics, or wirelessly via both noncontact capacitive coupling and Bluetooth low-energy radio link. The developed sensor concept is finally demonstrated in smart window prototypes, in which integrated piezoelectric sensors are used to detect break-in attempts. Additionally, each prototype includes an electrochromic film to control the light transmittance of the window, a screen printed electrochromic display for status indications and wireless communication with an external server, and a holistic approach of hybrid printed electronic systems targeting smart multifunctional glass applications.
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- Börlin, Niclas, 1968-, et al.
(author)
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A globally convergent gauss-newton algorithm for the bundle adjustment problem with functional constraints
- 2003
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In: Optical 3-D measurement techniques. - : Wichmann-Verlag. ; , s. 269-276
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Book chapter (other academic/artistic)abstract
- This paper describes a Gauss-Newton-based algorithm for the bundle adjustment problem with functional constraints (GNC). The GNC algorithm has superior theoretical convergence properties compared to the conventional bundle algorithm. Both algorithms were applied to simulated measurements of a sphere with 2-3 cameras and 4-9 points. For 2 cameras and 4-5 points, the GNC converged in substantially more cases. For the other configurations, the convergence properties were similar. The added cost for the GNC algorithm was less than 0.01 iterations on average. The GNC algorithm need to be evaluated on real-world problems, but the results suggest that the algorithm will be more reliable for minimum data problems and have a minimal overhead for easy problems.
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- Börlin, Niclas, 1968-, et al.
(author)
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Pros and cons of constrained and unconstrained formulation of the bundle adjustment problem
- 2004
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In: ISPRS Congress Istanbul 2004, Proceedings of Commission III. - : ISPRS. ; , s. 589-594
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Conference paper (other academic/artistic)abstract
- Two implementations of the bundle adjustment problem were applied to a subset of the Zurich City Hall reference data set. One implementation used the standard Euler angle parameterisation of the rotation matrix. The second implementation used all nine elements of the rotation matrix as unknowns and six functional constraints. The second formulation was constructed to reduce the non-linearity of the optimisation problem. The hypothesis was that a lower degree of non-linearity would lead to faster convergence. Furthermore, each implementation could optionally use the line search damping technique known from optimisation theory. The algorithms were used to solve the relative orientation problem for a varying number of homologous points from 33 different camera pairs. The results show that the constrained formulation has marginally better convergence properties, with or without damping. However, damping alone halves the number of convergence failures at a minor computational cost. The conclusion is that except to avoid the singularities associated with the Euler angles, the preferred use of the constrained formulation remains an open question. However, the results strongly suggest that the line search damping technique should be included in standard implementations of the bundle adjustment algorithm.
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- Campbell, D, et al.
(author)
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The cyanobacterium Synechococcus resists UV-B by exchanging photosystem II reaction-center D1 proteins
- 1998
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In: Proceedings of the National Academy of Sciences of the United States of America. - 0027-8424 .- 1091-6490. ; 95:1, s. 364-369
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Journal article (peer-reviewed)abstract
- Current ambient UV-B levels can significantly depress productivity in aquatic habitats, largely because UV-B inhibits several steps of photosynthesis, including the photooxidation of water catalyzed by photosystem II, We show that upon UV-B exposure the cyanobacterium Synechococcus sp, PCC 7942 rapidly changes the expression of a family of three psbA genes encoding photosystem II D1 proteins, In wild-type cells the psbAI gene is expressed constitutively, but strong accumulations of psbAII and psbAIII transcripts are induced within 15 min of moderate UV-B exposure (0.4 W/m(2)), This transcriptional response causes an exchange of two distinct photosystem II D1 proteins, D1:1 is encoded by psbAI, but on UV-B exposure, it is largely replaced by the alternate D1:2 form, encoded by both psbAII and psbAIII, The total content of D1 and other photosystem II reaction center protein, D2, remained unchanged throughout the UV exposure, as did the content and composition of the phycobilisome, Wild-type cells suffered only slight transient inhibition of photosystem II function under UV-B exposure, In marked contrast, under the same UV-B treatment, a mutant strain expressing only psbAI suffered severe (40%) and sustained inhibition of photosystem II function, Another mutant strain with constitutive expression of psbAII and psbAIII was almost completely resistant to the UV-B treatment, showing no inhibition of photosystem II function and only a slight drop in electron transport, In Synechococcus the rapid exchange of alternate D1 forms, therefore, accounts for much of the cellular resistance to UV-B inhibition of photosystem II activity and photosynthetic electron transport, This molecular plasticity may be an important element in community-level responses to UV-B, where susceptibility to UV-B inhibition of photosynthesis changes diurnally.
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- Constantin, Aurora, et al.
(author)
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Pushing the boundaries of participatory design with children with special needs
- 2019
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In: Proceedings of the 18th ACM International Conference on Interaction Design and Children, IDC 2019. - New York, NY, USA : ACM. ; , s. 697-705
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Conference paper (peer-reviewed)abstract
- © 2019 Association for Computing Machinery. Despite its inherent challenges, participatory design (PD) has unique benefits when designing technology for children, especially children with special needs. Researchers have developed a multitude of PD approaches to accommodate specific populations. However, a lack of understanding of the appropriateness of existing approaches across contexts presents a challenge for PD researchers. This workshop will provide an opportunity for PD researchers to exchange and reflect on their experiences of designing with children with special needs. We aim to identify, synthesize and collate PD best practices across contexts and participant groups.
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- Eriksson, Anders, et al.
(author)
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Fear of Eternal Damnation
- 2001
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In: Paul and Pathos. - 1589830113 ; , s. 115-126
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Book chapter (peer-reviewed)
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10. |
- Eriksson, Jerry, et al.
(author)
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Load bearing timber glass composites : A WoodWisdom-Net project for innovative building system
- 2013
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In: COST Action TU0905 Mid-term Conference on Structural Glass. - Boca Raton, Fla : CRC Press. - 9781138000445
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Conference paper (peer-reviewed)abstract
- The aim of this three year project, which is part of the WoodWisdom-Net researchprogram, is to develop an innovative load bearing building system composed of timberglasscomposites. The structural loads applied onto these composites will be transferred to, andsupported by, the glass component, in contrary to today’s traditional solutions where glass elementsonly function as an environmental shield. Using such structural elements will make itpossible to largely increase the glass surface in buildings, allowing the presence of more naturallight in personal homes and office buildings.Timber-glass shear walls and beams will be developed taking into consideration long-term behaviorand seismic performance. Design concepts, feasibility studies and performance assessmentsof these components will be performed in order to improve the overall performance. Theproject also includes the development of new design calculations as well as the optimization ofmanufacturing methods.Material properties of timber, glass and adhesives will be determined from small and large scaleexperimental investigations, and will be used as input for theoretical calculations and modelingwork. The projects industrial partners will function as expertise and take part in the developmentand construction of demonstration objects.The project consortium is composed of academic and industrial partners from Austria, Sweden,Germany, Turkey, Slovenia, Chile, and Brazil. This paper presents material specifications andresults from small scale testing performed by the Swedish project partners.
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