| 1. |
- Andréasson, Niclas, 1976, et al.
(författare)
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An Introduction to Continuous Optimization, 3rd edition
- 2016
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Bok (övrigt vetenskapligt/konstnärligt)abstract
- This is the third edition of a book that was originally published in 2005. The book is used primarily in the teaching of the Chalmers course TMA947 Nonlinear Optimization.
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| 2. |
- Bonander, Carl, et al.
(författare)
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A regression discontinuity analysis of the social distancing recommendations for older adults in Sweden during COVID-19.
- 2022
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Ingår i: European Journal of Public Health. - : Oxford University Press. - 1101-1262 .- 1464-360X. ; 32:5, s. 799-806
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: This paper investigates the impact of a non-mandatory and age-specific social distancing recommendation on isolation behaviors and disease outcomes in Sweden during the first wave of the COVID-19 pandemic (March to July, 2020). The policy stated that people aged 70 years or older should avoid crowded places and contact with people outside the household.METHODS: We used a regression discontinuity design-in combination with self-reported isolation data from COVID Symptom Study Sweden (n = 96,053; age range: 39-79 years) and national register data (age range: 39-100+ years) on severe COVID-19 disease (hospitalization or death, n = 21,804) and confirmed cases (n = 48,984)-to estimate the effects of the policy.RESULTS: Our primary analyses showed a sharp drop in the weekly number of visits to crowded places (-13%) and severe COVID-19 cases (-16%) at the 70-year-threshold. These results imply that the age-specific recommendations prevented approximately 1,800 to 2,700 severe COVID-19 cases, depending on model specification.CONCLUSION: It seems that the non-mandatory, age-specific recommendations helped control COVID-19 disease during the first wave of the pandemic in Sweden, as opposed to not implementing a social distancing policy aimed at older adults. Our study provides empirical data on how populations may react to non-mandatory, age-specific social distancing policies in the face of a novel virus.SUPPLEMENTARY MATERIAL: Online appendix with figures, tables, extra methods and results.
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| 3. |
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| 4. |
- Gustavsson, Anton, et al.
(författare)
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Exploring the utility of AR for quality inspections in timber-frame house production – A case study from Småland, Sweden
- 2021
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Ingår i: Proceedings of the 38th International Conference of CIB W78. ; , s. 304-314
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Konferensbidrag (refereegranskat)abstract
- About 80% of new homes in Sweden are being built using prefabricated elements. This rate of prefabrication is the highest in the world and the manufacturing of timber-frame homes has become a modern sector of the economy in Sweden. Information, and communication technology (ICT) has long played a key role in industrializing the wood-based building industry and novel ICT, like augmented reality, are believed to provide new opportunities. It is in this context that we explore how artificial reality solutions can be applied to improve the quality assurance process in a company producing prefabricated homes in Småland, Sweden. The research question asked in this study is: How can augmented reality be successfully applied to support quality assurance practice in the wood-based building industry? This question warrants investigation since improving quality assurance in house manufacturing not only improves products but also increases customer satisfaction. To investigate this question, we conduct a case study in a company where we set up a quasi-experiment with five quality assurance professionals using Microsoft’s HoloLens displaying production data. To make sense of their experiences, we conducted a series of semi-structured de-briefing interviews. Moreover, for understanding how AR can be successfully deployed in quality assurance we apply the design science research method. Findings are that the success of using AR in quality assurance depends on the quality of information displayed on the system, the geolocation of the models, the quality of the software and hardware used, and the ruggedness of the devices. We claim to have provided a range of valuable practical and theoretical contributions transferable to other construction companies seeking to apply augmented reality in their quality assurance routines.
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| 5. |
- Gyllensvärd, Magnus, et al.
(författare)
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Visualizing Energy Consumption of Radiators
- 2006
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Ingår i: Persuasive Technology. - Berlin, Heidelberg : Springer Berlin/Heidelberg. - 9783540342915 - 9783540342939 ; , s. 167-170
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Bokkapitel (refereegranskat)abstract
- Heating is a significant expenditure of many households today but the actual power consumption of the heating devices are seldom recognized. To help people understand and reflect upon their domestic energy consumption, we have designed an electrical radiator that emits heat entirely from light bulbs. This appliance responds to temperature changes in the room via sensors. The idea was to combine the product semantics of lamps and radiators and direct focus on the latter neglected product category. We argue that by re-designing domestic appliances adding means to visualize energy consumption in engaging and interesting ways it is possible to make energy utilization less abstract and easier to comprehend.
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| 6. |
- Hybelius, Jonna, 1993-, et al.
(författare)
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A unified Internet-delivered exposure treatment for undifferentiated somatic symptom disorder : single-group prospective feasibility trial
- 2022
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Ingår i: Pilot and Feasibility Studies. - : Springer Science and Business Media LLC. - 2055-5784. ; 8
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Tidskriftsartikel (refereegranskat)abstract
- Background: Exposure-based psychological treatment appears to have beneficial effects for several patient groups that commonly report distress related to persistent somatic symptoms. Yet exposure-based treatment is rarely offered in routine care. This may be because existing treatment protocols have been developed for specific symptom clusters or specific unwanted responses to somatic symptoms, and many clinics do not have the resources to offer all these specialised treatments in parallel. In preparation for a randomised controlled trial, we investigated the feasibility of a new and unified Internet-delivered exposure treatment (OSF.io: cnbwj) for somatic symptom disorder regardless of somatic symptom domain (e.g. cardiopulmonary, fatigue, gastrointestinal, pain), combination of unwanted emotions (e.g. anger, anxiety, fear, shame) and whether somatic symptoms are medically explained or not. We hypothesised that a wide spectrum of subgroups would show interest, that the treatment would be rated as credible, that adherence would be adequate, that the measurement strategy would be acceptable and that there would be no serious adverse events.Methods: Single-group prospective cohort study where 33 self-referred adults with undifferentiated DSM-5 somatic symptom disorder took part in 8 weeks of unified Internet-delivered exposure treatment delivered via a web platform hosted by a medical university. Self-report questionnaires were administered online before treatment, each week during treatment, post treatment and 3 months after treatment.Results: Participants reported a broad spectrum of symptoms. The Credibility/Expectancy mean score was 34.5 (SD = 7.0, range: 18–47). Participants completed 91% (150/165) of all modules and 97% of the participants (32/33) completed at least two exposure exercises. The average participant rated the adequacy of the rationale as 8.4 (SD = 1.5) on a scale from 0 to 10. The post-treatment assessment was completed by 97% (32/33), and 84% (27/32) rated the measurement strategy as acceptable. The Client Satisfaction Questionnaire mean score was 25.3 (SD = 4.7, range: 17–32) and no serious adverse events were reported. Reductions in subjective somatic symptom burden (the Patient Health Questionnaire 15; d = 0.90) and symptom preoccupation (the somatic symptom disorder 12; d = 1.17) were large and sustained.Conclusions: Delivering a unified Internet-delivered exposure-based treatment protocol for individuals with undifferentiated somatic symptom disorder appears to be feasible.
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| 7. |
- Kannan, Bharath, et al.
(författare)
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Waveguide quantum electrodynamics with superconducting artificial giant atoms
- 2020
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 583:7818, s. 775-779
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Tidskriftsartikel (refereegranskat)abstract
- Models of light–matter interactions in quantum electrodynamics typically invoke the dipole approximation1,2, in which atoms are treated as point-like objects when compared to the wavelength of the electromagnetic modes with which they interact. However, when the ratio between the size of the atom and the mode wavelength is increased, the dipole approximation no longer holds and the atom is referred to as a ‘giant atom’2,3. So far, experimental studies with solid-state devices in the giant-atom regime have been limited to superconducting qubits that couple to short-wavelength surface acoustic waves4–10, probing the properties of the atom at only a single frequency. Here we use an alternative architecture that realizes a giant atom by coupling small atoms to a waveguide at multiple, but well separated, discrete locations. This system enables tunable atom–waveguide couplings with large on–off ratios3 and a coupling spectrum that can be engineered by the design of the device. We also demonstrate decoherence-free interactions between multiple giant atoms that are mediated by the quasi-continuous spectrum of modes in the waveguide—an effect that is not achievable using small atoms11. These features allow qubits in this architecture to switch between protected and emissive configurations in situ while retaining qubit–qubit interactions, opening up possibilities for high-fidelity quantum simulations and non-classical itinerant photon generation12,13.
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| 8. |
- Patriksson, Michael, 1964, et al.
(författare)
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Introduction to Continuous Optimization
- 2013
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Bok (övrigt vetenskapligt/konstnärligt)abstract
- This second edition introduces several areas and items that were not included in the first edition, as well as several corrections. A brief summary of these changes are given next. Chapter 1 includes a discussion on the diet problem, in addition to that on the staff planning problem, in order to very early on introduce linear programming. Figure 1.1 now has the terminating box ``Implementation'', whereas the original one had an infinite loop! Chapter 3 has been enriched by several new results on separating and supporting hyperplanes, and the associated theory of convex cones and their polar sets. Thanks to this study of separating hyperplanes,Theorem 5.17 on the necessity of the Fritz John conditions now has a complete proof. The end of Chapter 5 also includes a summary of the fascinating story of the development of the Karush--Kuhn--Tucker conditions. The sensitivity analysis in linear programming has been expanded with a discussion in Section 10.5.3 on the addition of a variable or a constraint, as well as an introduction to column generation based on the example of the minimum cost multi-commodity network flow problem (Section 10.6). Chapter 11 includes a brief discussion on Gauss--Newton methods for least-squares problems. Chapter 12 has changed its name from ``Optimization over convex sets'' to ``Feasible-direction methods,'' in order to reflect the fact that the scope is now wider---from essentially polyhedral sets to general closed sets (which, however, most often will be assumed to be convex). In particular, we have added new sections on algorithms defined by closed descent maps---an algorithm principle which was devised and analyzed mainly in the 1960s, and which is a quite elegant means to describe iterative methods. We also utilize this principle to contrast established convergent methods (such as the Frank--Wolfe method) and failed attempts (such as the algorithm of Zoutendijk). We have also added a brief discussion on reduced gradient methods, which are relatives to the simplex method; they are---in their original statement---not convergent, but a small adjustment results in a closed descent map and hence a convergent method. Exercises and their solutions are now placed at the end of the book, rather than at the end of each chapter. The first edition from 2005 has been used in teaching of several courses at Chalmers University of Technology and the University of Gothenburg. We wish to thank all the students who have given us remarks on the book. We would also like to thank Dr. Kin Cheong Sou for remarks and corrections on the first edition.
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| 9. |
- Thunman, Henrik, 1970, et al.
(författare)
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Economic assessment of advanced biofuel production via gasification using cost data from the GoBiGas plant
- 2019
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Ingår i: Energy Science and Engineering. - : Wiley. - 2050-0505. ; 7:1, s. 217-229
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Tidskriftsartikel (refereegranskat)abstract
- This paper describes an economic analysis of the GoBiGas plant, which is a first-of-its-kind industrial installation for advanced biofuel production (ABP) via gasification, in which woody biomass is converted to biomethane. A previous technical evaluation of the demonstration unit confirmed that it is technically feasible to construct advanced biofuel production plants, using commercially available and widely used components. Thus, significant cost reductions for equipment cannot be expected as a consequence of learning effects. However, the equipment itself accounted for <20% of the total investment cost at GoBiGas and there exists the potential to reduce the production cost through learning how to assemble the process and reduce project-specific costs. The analysis shows that a plant with capacity of 200 MW of biomethane is an attractive scale for future stand-alone ABP plants with respect to limiting the production cost. For a 200-MW ABP plant operated using forest residues as fuel, the production cost for biomethane is estimated at approximately 600 SEK/MWh, (60€/MWh, 75US$/MWh), which is equivalent to 5.4 SEK/liter gasoline [0.54 €/liter, or 2.5USD per gallon (9.9 SEK/€, 8 SEK/USD)], where the feedstock accounts for about 36% of the production cost. The most significant uncertainty factors pertaining to the estimated production costs are expected to relate to: trade conditions; the location of the installation; and the local price of feedstock. Thus, there is some potential for implementing cost-competitive ABP systems of smaller capacity if low-grade feedstocks (eg, waste-derived woody biomass) can be utilized, and/or if the unit can be integrated with the already existing infrastructure.
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