| 1. |
- Fredenberg, Erik, 1979-
(författare)
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Spectral Mammography with X-Ray Optics and a Photon-Counting Detector
- 2009
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Early detection is vital to successfully treating breast cancer, and mammography screening is the most efficient and wide-spread method to reach this goal. Imaging low-contrast targets, while minimizing the radiation exposure to a large population is, however, a major challenge. Optimizing the image quality per unit radiation dose is therefore essential. In this thesis, two optimization schemes with respect to x-ray photon energy have been investigated: filtering the incident spectrum with refractive x-ray optics (spectral shaping), and utilizing the transmitted spectrum with energy-resolved photon-counting detectors (spectral imaging). Two types of x-ray lenses were experimentally characterized, and modeled using ray tracing, field propagation, and geometrical optics. Spectral shaping reduced dose approximately 20% compared to an absorption-filtered reference system with the same signal-to-noise ratio, scan time, and spatial resolution. In addition, a focusing pre-object collimator based on the same type of optics reduced divergence of the radiation and improved photon economy by about 50%. A photon-counting silicon detector was investigated in terms of energy resolution and its feasibility for spectral imaging. Contrast-enhanced tumor imaging with a system based on the detector was characterized and optimized with a model that took anatomical noise into account. Improvement in an ideal-observer detectability index by a factor of 2 to 8 over that obtained by conventional absorption imaging was found for different levels of anatomical noise and breast density. Increased conspicuity was confirmed by experiment. Further, the model was extended to include imaging of unenhanced lesions. Detectability of microcalcifications increased no more than a few percent, whereas the ability to detect large tumors might improve on the order of 50% despite the low attenuation difference between glandular and cancerous tissue. It is clear that inclusion of anatomical noise and imaging task in spectral optimization may yield completely different results than an analysis based solely on quantum noise.
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| 2. |
- Stolen, Reidar, et al.
(författare)
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Solcelleteknologi og brannsikkerhet
- 2018
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Bruken av solcelleteknologi er i stor vekst i Norge. I denne studien er branntekniske utfordringer ved bruk av solcelleteknologi undersøkt, med hensyn på brannstart, brannspredning og brannslokking. Studien danner et kunnskapsgrunnlag for å ivareta brannsikkerheten under montering, drift og under slokkeinnsats, samt for å utforme et enhetlig og tydelig regelverk. Resultatene fra studien viser:Brannstart: Solcelleinstallasjoner inneholder mange koblingspunkt, som kan være potensielle tennkilder, og en liten mengde brennbare materialer. Dermed er det som trengs til stede for å starte en brann. Det er viktig at alle kontaktpunkter i solcelleinstallasjonen er robuste og tåler den påkjenningen de blir utsatt for gjennom sin levetid uten at det oppstår dårlig kontakt som kan føre til brann.Brannspredning: For utenpåmonterte solcellemoduler er det ofte en åpen luftspalte mellom modul og bygning. Dersom det er en brann i denne luftspalten, vil varmen kunne bli akkumulert, noe som kan føre til raskere og større brannspredning enn om bygningsoverflaten ikke hadde vært tildekket. I fullskalaforsøk med solcellemoduler montert på tak spredte brannen seg under hele arealet som var dekket av moduler, men stoppet da den nærmet seg kanten av dette arealet. Dette illustrerer viktigheten av at områder med solceller utenpå en bygning blir seksjonert for å unngå brannspredning. Eventuelt kan det benyttes mindre brennbare materialer på taket under solcellemodulene for å motvirke den økte varmepåkjenningen som solcellemodulene gir. Luftspalten mellom modul og bygning kan potensielt også gi endringer i luftstrømningen langs bygget, som igjen kan påvirke brannspredningen.Brannslokking: Brannvesenet har behov for informasjon om det er solcelleinstallasjon i bygget og hvilke deler av det elektriske anlegget som kan være spenningssatt. Under slokkeinnsats må brannvesenet ta hensyn til berøringsfare, og fare for at det kan oppstå lysbuer og andre feil som kan føre til nye antennelsespunkt. Ferskvann kan brukes som slokkemiddel, dette må spyles fra minimum 1 meters avstand med spredt stråle og minimum 5 meters avstand med samlet stråle. Solcellemoduler kan komplisere brannslokking ved at de danner en fysisk barriere mellom brannvesenet og brannen, samt fordi det må tas hensyn til plassering av spenningssatte komponenter. Når disse punktene er tatt høyde for, bør ikke utenpåmonterte solcelleinstallasjoner være et problem.Videre arbeid: For utenpåmonterte solcelleinstallasjoner, er det lite forskning på vertikal montering (på fasader), og hvordan en eventuell endret branndynamikk kan påvirke brannspredning og slokking. Videre er det i dag økende bruk av bygningsintegrerte solcelleinstallasjoner, noe som gir mange mulige nye utfordringer for brannsikkerheten og for regelverk, ettersom solcellen da er en del av bygningskroppen, samtidig som den er en elektrisk komponent. Tysk statistikk tyder på at brannrisiko for slike installasjoner kan være større enn for utenpåmonterte solcelleinstallasjoner, og dette vil det derfor være viktig å undersøke nærmere.
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| 3. |
- Amundin, Mats, et al.
(författare)
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A proposal to use distributional models to analyse dolphin vocalisation
- 2017
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Ingår i: Proceedings of the 1st International Workshop on Vocal Interactivity in-and-between Humans, Animals and Robots, VIHAR 2017. - 9782956202905 ; , s. 31-32
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Konferensbidrag (refereegranskat)abstract
- This paper gives a brief introduction to the starting points of an experimental project to study dolphin communicative behaviour using distributional semantics, with methods implemented for the large scale study of human language.
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| 4. |
- Chen, Zhe, et al.
(författare)
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Nano-scale characterization of white layer in broached Inconel 718
- 2017
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Ingår i: Materials Science & Engineering A: Structural Materials: Properties, Microstructure and Processing. - Amsterdam : Elsevier BV. - 0921-5093 .- 1873-4936. ; 684, s. 373-384
-
Tidskriftsartikel (refereegranskat)abstract
- The formation mechanism of white layers during broaching and their mechanical properties are not well investigated and understood to date. In the present study, multiple advanced characterization techniques with nano-scale resolution, including transmission electron microscopy (TEM), transmission Kikuchi diffraction (TKD), atom probe tomography (APT) as well as nano-indentation, have been used to systematically examine the microstructural evolution and corresponding mechanical properties of a surface white layer formed when broaching the nickel-based superalloy Inconel 718.TEM observations showed that the broached white layer consists of nano-sized grains, mostly in the range of 20–50 nm. The crystallographic texture detected by TKD further revealed that the refined microstructure is primarily caused by strong shear deformation. Co-located Al-rich and Nb-rich fine clusters have been identified by APT, which are most likely to be γ′ and γ′′ clusters in a form of co-precipitates, where the clusters showed elongated and aligned appearance associated with the severe shearing history. The microstructural characteristics and crystallography of the broached white layer suggest that it was essentially formed by adiabatic shear localization in which the dominant metallurgical process is rotational dynamic recrystallization based on mechanically-driven subgrain rotations. The grain refinement within the white layer led to an increase of the surface nano-hardness by 14% and a reduction in elastic modulus by nearly 10% compared to that of the bulk material. This is primarily due to the greatly increased volume fraction of grain boundaries, when the grain size was reduced down to the nanoscale.
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| 5. |
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| 6. |
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| 7. |
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| 8. |
- Schötz, Susanne, et al.
(författare)
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Phonetic Characteristics of Domestic Cat Vocalisations
- 2017
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Ingår i: Proceedings of the 1st International Workshop on Vocal Interactivity in-and-between Humans, Animals and Robots, VIHAR 2017. - 9782956202905 ; , s. 5-6
-
Konferensbidrag (refereegranskat)abstract
- The cat (Felis catus, Linneaus 1758) has lived around or with humans for at least 10,000 years, and is now one of the most popular pets of the world with more than 600 millionindividuals. Domestic cats have developed a more extensive, variable and complex vocal repertoire than most other members of the Carnivora, which may be explained by their social organisation, their nocturnal activity and the long period of association between mother and young. Still, we know surprisingly little about the phonetic characteristics of these sounds, and about the interaction between cats and humans.Members of the research project Melody in human–cat communication (Meowsic) investigate the prosodic characteristics of cat vocalisations as well as the communication between human and cat. The first step includes a categorisation of cat vocalisations. In the next step it will be investigated how humans perceive the vocal signals of domestic cats. This paper presents an outline of the project which has only recently started.
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| 9. |
- Hosseini Bab Anari, Elham, 1982, et al.
(författare)
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Fluorine-free salts for aqueous lithium-ion and sodium-ion battery electrolytes
- 2016
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Ingår i: RSC Advances. - : Royal Society of Chemistry (RSC). - 2046-2069. ; 6:88, s. 6, 85194-85201
-
Tidskriftsartikel (refereegranskat)abstract
- A first generation of fluorine-free lithium and sodium salts based on the concept of pseudo-delocalized anions has been synthesized with both high purity and yield using water as the solvent in the reaction medium. The salts have been fully characterized by Raman and FT-IR spectroscopies, thermogravimetry, and X-ray crystallography to reveal both basic properties in terms of thermal stability and solubility as well as the local, mainly ion–ion interaction dictated, coordination details and by ionic conductivity and electrochemical stability window measurements as aqueous electrolytes. Together a picture is created of the salts' promise as components in electrolytes – primarily aiming at application in low voltage fluorinefree aqueous lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs).
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| 10. |
-
INNOTRACK: Concluding technical report
- 2010
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Samlingsverk (redaktörskap) (refereegranskat)abstract
- The track structure, rails, switches and crossings account for more than 50% of maintenance and renewal costs for the rail industry. To improve the competitiveness of rail transportation, the cost-efficiency of these areas needs to be addressed.This the background to INNOTRACK, an integrated research project funded by the European Commission’s 6th research framework pro- gramme. Running from September 2006 to December 2009, INN- OTRACK has developed a multitude of innovative solutions in the areas of track substructure, rails & welds, and switches & crossings. The solutions have been assessed from technical, logistics and life cycle cost point of views.This Concluding Technical Report of INNOTRACK includes an overview of the project. It further details implementable results, and clusters them into ”highlight” areas. In addition, the book acts as a ”key” to the vast amount of information from INNOTRACK: All sections refer to project reports where more information can be found.
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| 11. |
- Stylidis, Kostas, 1978, et al.
(författare)
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Perceived quality framework in product generation engineering: an automotive industry example
- 2019
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Ingår i: Design Science. - : Cambridge University Press (CUP). - 2053-4701 .- 2053-4701. ; 5
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Tidskriftsartikel (refereegranskat)abstract
- Perceived quality refers to customers’ cognitive and emotional responses to a particular design, often also associated with craftsmanship and customer satisfaction. Previous research defined a taxonomy of perceived quality and provided understanding about how engineering design decisions impact customer satisfaction. Furthermore, development of new products is frequently based on carrying over attributes of existing products, either from the same producer or from competitors. Previous research offered a new product development methodology combining variations of subsystems to carry over from existing products. This brief presents how these two lines of research combined to design the central console of the Porsche Panamera automobile and discusses the opportunities and challenges posed in the practical implementation of this research.
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| 12. |
- Ribeiro, Luis, et al.
(författare)
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Industrial Agents for the Fast Deployment of Evolvable Assembly Systems
- 2015. - 1st ed.
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Ingår i: Industrial Agents. - Amsterdam, Netherlands : Elsevier. - 9780128003411 ; , s. 301-321, s. 301-322
-
Bokkapitel (refereegranskat)abstract
- The current manufacturing scenario is characterized by high market unpredictability. Agility is therefore a central challenge for modern companies that need to understand and be proactive towards their product offer in respect to “what is offered, when it is offered, where, how and by whom” (Brown & Bessant 2003).The “what” and the “when” are particularly relevant to the research in emerging paradigms as they account for variety, customization and volume; and timing, speed and seasonality (Brown & Bessant 2003).In this scenario, several design approaches and models have been proposed in the last decade to enable re-configurability and subsequently enhance the companies’ ability to adjust their offer in nature and time.From a paradigmatic point of view research has concentrated on the organizational structure of the shop-floor and the associated controls aspects. Concepts like Reconfigurable Manufacturing Systems (RMS) (Koren & Shpitalni 2010) and Fractal Factories (FF) (Montreuil 1999) support the physical construction of production systems by regulating their layout and making a few assumptions on their logical organization. On the other hand, concepts like Bionic Manufacturing Systems (BMS)(Ueda 1992), Holonic Manufacturing Systems (HMS)(Van Brussel et al. 1998), Evolvable Assembly Systems (Ribeiro et al. 2010) essentially provide the theoretical guidelines for the logical/computational organization of the system (see (Tharumarajah 1996) for a comparison between BMS, HMS and FF and (Setchi & Lagos 2004) for the rationale supporting the shift from Dedicated Lines to Flexible Manufacturing System and finally RMS).While these paradigms provide the conceptual framework and the main design guidelines their actual interpretation and implementation has led to a wider set of architectures (Monostori, Váncza & Kumara 2006; Leitão 2009; Parunak 2000; Pěchouček & Mařík 2008).These architectures align the high-level principles with the technological offer and limitations while seeking to address the re-configurability requirements of (Mehrabi, Ulsoy & Koren 2000; Rösiö & Säfsten 2013):module mobility – modules are easy and quick to move and install;“diagnosability” – it is quick to identify the sources of quality and reliability problems;“integrability” – modules are easy to integrate into the rest of the system.“convertibility” – it is easy and quick to switch between existing products and it is easy to adapt the system to future products;scalability – it is easy to enlarge and downsize the production system;“automatibility” – a dynamic level of automation is enabled;modularity – all system elements are designed to be modular;customization – the capability and flexibility of the production system is designed according to the products to be produced in the system.Instant deployment, as addressed in the present chapter directly addresses mobility, “integrability”, “convertibility”, scalability and customization. Mechatronic modularity is a prerequisite and is enforced by the proposed architecture and the considered modular design. “Diagnosability” was not specifically tackled.In this context, the chapter analyses the agent-based architecture related with the Instantly Deployable Evolvable Assembly System (IDEAS) project that is inspired by the Evolvable Assembly System (EAS) paradigm (Ribeiro et al. 2010) as a mechanism to enable fast deployment of mechatronic modules. EAS advocates the use of process-oriented modules and envisions the production system as a collection of processes and the associated interacting agents.The architecture and the related test cases are used to draw the main lessons learned in respect to technological and conceptual implications.In this context, the remainder of this text is organized as follows: section 1.1 discusses the main deployment challenges, section 1.2 details the reference architecture and associated concepts, section 1.3 presents the principal implementation decisions, section 1.4 features the main lessons learned, sections 1.5 discusses the benefits of the proposed approach and finally section 1.6 reflects on the main conclusions.
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| 13. |
- Eivazihollagh, Alireza, et al.
(författare)
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On chelating surfactants : Molecular perspectives and application prospects
- 2019
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Ingår i: Journal of Molecular Liquids. - : Elsevier BV. - 0167-7322 .- 1873-3166. ; 278, s. 688-705
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Tidskriftsartikel (refereegranskat)abstract
- Chelating agents, molecules that very strongly coordinates certain metal ions, are used industrially as well as in consumer products to minimize disturbances and increase performance of reactions and applications. The widely used sequestering agents, nitrilotriacetic acid (NTA), ethylenediaminetetraacetic acid (EDTA) and diethylenetriaminepentaacetic acid (DTPA) belong to this branch of readily water-soluble compounds. When these chemical structures also have hydrophobic parts, they are prone to adsorb at air-water interfaces and to self-assemble. Such bifunctional molecules can be called chelating surfactants and will have more extended utilization prospects than common chelating agents or ordinary ionic surfactants. The present review attempts to highlight the fundamental behavior of chelating surfactants in solution and at interfaces, and their very specific interactions with metal ions. Methods to recover chelating surfactants from metal chelates are also described. Moreover, utilization of chelating surfactants in applications for metal removal in environmental engineering and mineral processing, as well as for metal control in the fields of biology, chemistry and physics, is exemplified and discussed.
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| 14. |
- Nybacka, Mikael, et al.
(författare)
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Project: CASTT - Centre for Automotive Systems Technologies and Testing
- 2007
-
Annan publikation (populärvet., debatt m.m.)abstract
- Through the Centre for Automotive Systems Technologies and Testing, Luleå University of Technology aims to first of all support automotive winter testing in Northern Sweden. This means to support the local automotive test entrepreneurs and through them their customers: the car manufacturers and their suppliers. To succeed in this task, the center relies on the university's areas of leading research and most importantly on the cooperation between those areas.
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| 15. |
- Shafiq, ur Réhman, 1978-, et al.
(författare)
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Using Vibrotactile Language for Multimodal Human Animals Communication and Interaction
- 2014
-
Ingår i: Proceedings of the 2014 Workshops on Advances in Computer Entertainment Conference, ACE '14. - New York, NY, USA : Association for Computing Machinery (ACM). - 9781450333146 ; , s. 1:1-1:5
-
Konferensbidrag (refereegranskat)abstract
- In this work we aim to facilitate computer mediated multimodal communication and interaction between human and animal based on vibrotactile stimuli. To study and influence the behavior of animals, usually researchers use 2D/3D visual stimuli. However we use vibrotactile pattern based language which provides the opportunity to communicate and interact with animals. We have performed experiment with a vibrotactile based human-animal multimodal communication system to study the effectiveness of vibratory stimuli applied to the animal skin along with audio and visual stimuli. The preliminary results are encouraging and indicate that low-resolution tactual displays are effective in transmitting information.
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| 16. |
- Frid, Emma, 1988-, et al.
(författare)
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Perceptual Evaluation of Blended Sonification of Mechanical Robot Sounds Produced by Emotionally Expressive Gestures : Augmenting Consequential Sounds to Improve Non-verbal Robot Communication
- 2021
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Ingår i: International Journal of Social Robotics. - : Springer Nature. - 1875-4791 .- 1875-4805.
-
Tidskriftsartikel (refereegranskat)abstract
- This paper presents two experiments focusing on perception of mechanical sounds produced by expressive robot movement and blended sonifications thereof. In the first experiment, 31 participants evaluated emotions conveyed by robot sounds through free-form text descriptions. The sounds were inherently produced by the movements of a NAO robot and were not specifically designed for communicative purposes. Results suggested no strong coupling between the emotional expression of gestures and how sounds inherent to these movements were perceived by listeners; joyful gestures did not necessarily result in joyful sounds. A word that reoccurred in text descriptions of all sounds, regardless of the nature of the expressive gesture, was “stress”. In the second experiment, blended sonification was used to enhance and further clarify the emotional expression of the robot sounds evaluated in the first experiment. Analysis of quantitative ratings of 30 participants revealed that the blended sonification successfully contributed to enhancement of the emotional message for sound models designed to convey frustration and joy. Our findings suggest that blended sonification guided by perceptual research on emotion in speech and music can successfully improve communication of emotions through robot sounds in auditory-only conditions.
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| 17. |
- Nielsen, Stig Anton, 1981, et al.
(författare)
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Propositional Architecture using Induced Representation
- 2014
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Ingår i: What’s the Matter? Materiality and Materialism at the Age of Computation. - 9789608932067 ; , s. 297-312
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Konferensbidrag (refereegranskat)abstract
- The paper describes a method and an approach to using sensor data, machine-learning and pattern recognition for proposing and guiding immediate modifications to the existing built environment. The proposed method; Induced Representation, consists of a few steps which we have identified as crucial for such an approach. The steps are A: data collection from the environment, B: machine cognition, learning, prediction, and, c: proposition, visualization, and embodied representations for quick implementation. In the paper we outline the factual and theoretical basis for this approach, and we present and discuss three experiments that each deal with the steps A, B and C.
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| 18. |
- Westin, Jonathan, 1980, et al.
(författare)
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Digitising Sensitive Heritage Monuments In Antarctica
- 2024
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Ingår i: The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Volume XLVIII-2/W4-2024. 10th International Workshop 3D-ARCH "3D Virtual Reconstruction and Visualization of Complex Architectures, 21–23 February 2024, Siena, Italy / editor(s): S. Campana, F. Fassi, and F. Remondino. - : International Society for Photogrammetry and Remote Sensing. - 1682-1750.
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Konferensbidrag (refereegranskat)abstract
- During the Antarctica expedition CHAQ2020, several cultural heritage sites – remains from the Swedish South Polar Expedition (1901–1903) – were documented using a range of different techniques and technologies. These physical monuments and environments are for all intents and purposes unavailable for most researchers due to their remote location and are also threatened by the effects of climate change. Hence, the deployed documentation techniques and technologies were selected both as a consequence of the inherently difficult conditions in Antarctica, where their reliance, durability, and speed were key considerations, but also for their perceived ability to document the unique and fragile environment. The documentation was carried out with the double intention of both allowing for observations in situ through processes of analytical drawings and data capture, but also capturing the environment as broadly and deeply as possible, in essence making a copy of it open for studies of unknown unknowns, that could serve as a source material for research questions still undefined. Hence, with the documentation of the winter station on Snow Hill Island as a case study, and with a perspective on documentation as a method through which to process, preserve, and disseminate information, this article serves to critically detail, compare, and evaluate the digital techniques and technologies that the expedition deployed to capture architectural elements and spatial contexts, and the data that could be obtained through these.
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| 19. |
- Liu, Yuanhua, 1971, et al.
(författare)
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Considering the importance of user profiles in interface design
- 2009
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Ingår i: User Interfaces. ; , s. 23-
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- User profile is a popular term widely employed during product design processes by industrial companies. Such a profile is normally intended to represent real users of a product. The ultimate purpose of a user profile is actually to help designers to recognize or learn about the real user by presenting them with a description of a real user’s attributes, for instance; the user’s gender, age, educational level, attitude, technical needs and skill level. The aim of this chapter is to provide information on the current knowledge and research about user profile issues, as well as to emphasize the importance of considering these issues in interface design. In this chapter, we mainly focus on how users’ difference in expertise affects their performance or activity in various interaction contexts. Considering the complex interaction situations in practice, novice and expert users’ interactions with medical user interfaces of different technical complexity will be analyzed as examples: one focuses on novice and expert users’ difference when interacting with simple medical interfaces, and the other focuses on differences when interacting with complex medical interfaces. Four issues will be analyzed and discussed: (1) how novice and expert users differ in terms of performance during the interaction; (2) how novice and expert users differ in the perspective of cognitive mental models during the interaction; (3) how novice and expert users should be defined in practice; and (4) what are the main differences between novice and expert users’ implications for interface design. Besides describing the effect of users’ expertise difference during the interface design process, we will also pinpoint some potential problems for the research on interface design, as well as some future challenges that academic researchers and industrial engineers should face in practice.
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| 20. |
- Kurdve, Martin, et al.
(författare)
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Can Social Sustainability Values be Incorporated in a Product Service System for Temporary Public Building Modules?
- 2017
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Ingår i: Procedia CIRP. - : Elsevier. - 2212-8271 .- 2212-8271. ; 64, s. 193-198
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Tidskriftsartikel (refereegranskat)abstract
- The temporary constructions industry has cost efficiency and sustainability challenges that may require new innovative business models as well as product and processes. This paperaims to discuss how social sustainability services can be included in product service system (PSS)by investigating a case where employment is offered in distributed temporary building module manufacturing in the PSS context. The case has been evaluated against PSS literature. Recent reviews and literature on inclusion of social sustainability and PSS for buildings were used. It is concluded that the current concept fits basic definitions of PSS although it is not typical. The social value of employment is difficult to evaluate and inclusion in PSS needs further research. Design practice could be used to further develop the services in the studied concept. © 2017 The Authors.
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| 21. |
- Fredenberg, Erik, PhD, 1979-, et al.
(författare)
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A low-absorption x-ray energy filter for small-scale applications
- 2009
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Ingår i: Optics Express. - : The Optical Society. - 1094-4087. ; 17:14, s. 11388-11398
-
Tidskriftsartikel (refereegranskat)abstract
- We present an experimental and theoretical evaluation of an x-ray energy filter based on the chromatic properties of a prism-array lens (PAL). It is intended for small-scale applications such as medical imaging. The PAL approximates a Fresnel lens and allows for high efficiency compared to filters based on ordinary refractive lenses, however at the cost of a lower energy resolution. Geometrical optics was found to provide a good approximation for the performance of a flawless lens, but a field-propagation model was used for quantitative predictions. The model predicted a 0.29 ΔE/E energy resolution and an intensity gain of 6.5 for a silicon PAL at 23.5 keV. Measurements with an x-ray tube showed good agreement with the model in energy resolution and peak energy, but a blurred focal line contributed to a 29% gain reduction. We believe the blurring to be caused mainly by lens imperfections, in particular at the periphery of the lens.
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| 22. |
- Heshmati, Mohsen, 1987, et al.
(författare)
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Dependency of cohesive laws of a structural adhesive in Mode-I and Mode-II loading on moisture, freeze-thaw cycling, and their synergy
- 2017
-
Ingår i: Materials and Design. - : Elsevier BV. - 1873-4197 .- 0264-1275. ; 122, s. 433-447
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Tidskriftsartikel (refereegranskat)abstract
- In recent years, adhesive bonding has found its way to construction applications such as bridges. Given the harsh conditions that such structures are usually exposed to, it is necessary to account for environmental factors, particularly moisture and temperature, in the design phase. Cohesive zone modelling has attracted much attention in the last decade as a promising method to design adhesive joints. Despite this interest, the effects of moisture and thermal cycles on cohesive laws have not been investigated to the knowledge of the authors. In this paper, we present a method to directly measure the environmental-dependent cohesive laws of a structural adhesive loaded in pure Mode-I and Mode-II. Special consideration is given to overcome issues such as the time-consuming nature of moisture ingression and specimen dimensions, which could be problematic due to the size-limitations of conditioning equipment. The accuracy of this method was verified through simulation of the experiments using the finite element analysis. The effects of exposure to 95% relative humidity, immersion in saltwater and distilled water, and freeze-thaw cycles in the presence or absence of moisture were investigated. The results indicate the damaging effects of combined saltwater and freeze-thaw cycles which were clearly reflected on the shape of the cohesive laws.
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| 23. |
- Decrop, Deborah, et al.
(författare)
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Single-step manufacturing of femtoliter microwell arrays in a novel surface energy mimicking polymer
- 2015
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Ingår i: 18th International Conference on Solid-State Sensors, Actuators and Microsystems (IEEE TRANSDUCER 2015). - : IEEE.
-
Konferensbidrag (refereegranskat)abstract
- We report a novel polymer material formulation and stamp-molding technique that enable rapid single-step manufacturing of hydrophilic-in-hydrophobic microwell arrays. We developed a modified thiol-ene-epoxy polymer (mOSTE+) formulation that mimics the surface energy of its mold during polymerization. The polymer inherits the surface energy from the mold through molecular self-assembly, in which functional monomers self-assemble at the interface between the liquid prepolymer and the mold surface. Combining this novel mOSTE+ material with a stamp-molding process leads to simultaneous surface energy mimicking and micro-structuring. This method was used to manufacture microwells with hydrophilic bottom and hydrophobic sidewall, depressed in a surrounding hydrophobic surface. The microwell arrays were successfully tested for the self-assembly of 62’000 femtoliter-droplets. Such femtoliter droplet arrays are useful for, e.g., digital ELISA and single cell/molecule analysis applications.
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| 24. |
- Pardon, Gaspard, 1983-
(författare)
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From Macro to Nano : Electrokinetic Transport and Surface Control
- 2014
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Today, the growing and aging population, and the rise of new global threats on human health puts an increasing demand on the healthcare system and calls for preventive actions. To make existing medical treatments more efficient and widely accessible and to prevent the emergence of new threats such as drug-resistant bacteria, improved diagnostic technologies are needed. Potential solutions to address these medical challenges could come from the development of novel lab-on-chip (LoC) for point-of-care (PoC) diagnostics.At the same time, the increasing demand for sustainable energy calls for the development of novel approaches for energy conversion and storage systems (ECS), to which micro- and nanotechnologies could also contribute.This thesis has for objective to contribute to these developments and presents the results of interdisciplinary research at the crossing of three disciplines of physics and engineering: electrokinetic transport in fluids, manufacturing of micro- and nanofluidic systems, and surface control and modification. By combining knowledge from each of these disciplines, novel solutions and functionalities were developed at the macro-, micro- and nanoscale, towards applications in PoC diagnostics and ECS systems.At the macroscale, electrokinetic transport was applied to the development of a novel PoC sampler for the efficient capture of exhaled breath aerosol onto a microfluidic platform.At the microscale, several methods for polymer micromanufacturing and surface modification were developed. Using direct photolithography in off-stoichiometry thiol-ene (OSTE) polymers, a novel manufacturing method for mold-free rapid prototyping of microfluidic devices was developed. An investigation of the photolithography of OSTE polymers revealed that a novel photopatterning mechanism arises from the off-stoichiometric polymer formulation. Using photografting on OSTE surfaces, a novel surface modification method was developed for the photopatterning of the surface energy. Finally, a novel method was developed for single-step microstructuring and micropatterning of surface energy, using a molecular self-alignment process resulting in spontaneous mimicking, in the replica, of the surface energy of the mold.At the nanoscale, several solutions for the study of electrokinetic transport toward selective biofiltration and energy conversion were developed. A novel, comprehensive model was developed for electrostatic gating of the electrokinetic transport in nanofluidics. A novel method for the manufacturing of electrostatically-gated nanofluidic membranes was developed, using atomic layer deposition (ALD) in deep anodic alumina oxide (AAO) nanopores. Finally, a preliminary investigation of the nanopatterning of OSTE polymers was performed for the manufacturing of polymer nanofluidic devices.
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