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| 46. |
- Malm, Johan, 1982-
(författare)
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Spectral-element simulations of turbulent wall-bounded flows including transition and separation
- 2011
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The spectral-element method (SEM) is used to study wall-bounded turbulent flowsin moderately complex geometries. The first part of the thesis is devoted to simulations of canonical flow cases, such as temporal K-type transitionand turbulent channel flow, to investigate general resolution requirements and computational efficiency of the numerical code nek5000. Large-eddy simulation (LES) is further performed of a plane asymmetric diffuser flow with an opening angle of 8.5 degrees, featuring turbulent flow separation. Good agreement with numerical studies of Herbst (2007) is obtained, and it is concluded that the use of a high-order method is advantageous for flows featuring pressure-induced separation. Moreover, it is shown, both a priori on simpler model problems and a posteriori using the full Navier--Stokes equations, that the numerical instability associated with SEM at high Reynolds numbers is cured either by employing over-integration (dealiasing) or a filter-based stabilisation, thus rendering simulations of moderate to high Reynolds number flows possible. The second part of the thesis is devoted to the first direct numerical simulation (DNS) of a truly three-dimensional, turbulent and separated diffuser flow at Re = 10 000 (based on bulk velocity and inflow-duct height), experimentally investigated by Cherry et al. (2008). The massively parallel capabilities of the spectral-element method are exploited by running the simulations on up to 32 768 processors. Very good agreement with experimental mean flow data is obtained and it is thus shown that well-resolved simulations of complex turbulent flows with high accuracy are possible at realistic Reynolds numberseven in complicated geometries. An explanation for the discovered asymmetry of the mean separated flow is provided and itis demonstrated that a large-scale quasi-periodic motion is present in the diffuser. In addition, a new diagnostic measure, based on the maximum vorticity stretching component in every spatial point, is designed and tested in a number of turbulent and transitional flows. Finally, Koopman mode decomposition is performed of a minimal channel flow and compared to classical proper orthogonal decomposition (POD).
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| 47. |
- Hultman, Jens, et al.
(författare)
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International retail sourcing development : the case of IKEA
- 2008
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Ingår i: Proceedings of the 1st Nordic Retail and Wholesale Conference.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The paper explores how international sourcing in retail operations in the case of IKEA of Sweden have evolved over time. The internationalization process of IKEA has been subject for quite a lot of scholarly attention over the years. In contrast to most other studies on the internationalization process of IKEA, this study has its focus on the development of international sourcing. International retail sourcing development in the case of IKEA is discussed over three themes concerning international retail sourcing development at IKEA; sourcing market development (where?), sourcing scope development (what?), and sourcing strategy development (how?). The paper identifies three distinct characteristics of IKEA’s sourcing operations can be identified. The paper suggests that although IKEA’s overarching goals and characteristics of sourcing operations have been consistent, the sourcing operations have still undergone significant change. The paper also suggests that the scope, the strategy selection and the market development aspects of retail sourcing development are highly interrelated.
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| 48. |
- León, Felipe
(författare)
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Being one of us: we-identities and self-categorization theory
- 2023
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Ingår i: Phenomenology and the Cognitive Sciences. - : SPRINGER. - 1568-7759 .- 1572-8676.
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Tidskriftsartikel (refereegranskat)abstract
- One way to theorize about we-identities-the identities that individual subjects have as one of us-is in terms of the uniformity, interchangeability, and prototypicality of group members. The social-psychological theory of self-categorization epitomizes this approach, which has strongly influenced contemporary phenomenological research on the we. This paper argues that this approach has one important and largely overlooked limitation: the we-identities tied to close personal relationships-exemplified by long-term friendships and romantic partnerships-are based on patterns of interpersonal interaction and integration through which individuals tend to grasp their non-substitutability and complementarity. This limitation suggests that another approach is needed to tackle the we-identities characteristic of close personal relationships. I outline such an approach, by combining resources from classical phenomenology and ongoing research on the socially extended mind.
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| 49. |
- Gerding, Henrik, et al.
(författare)
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The diffusion of architectural innovations : Modelling social networks in the ancient building trade
- 2017
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Ingår i: Sinews of empire : Networks in the Roman Near East and beyond - Networks in the Roman Near East and beyond. - 9781785705960 ; , s. 71-84
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Konferensbidrag (refereegranskat)abstract
- Within the project LATERES COCTILES early fired bricks have been the objectof a multifaceted investigation. One aim has been to elucidate the mechanisms behind the diffusion of this innovation. An inventory of Hellenistic and early Roman fired bricks around the Mediterranean resulted in an archaeological database comprising 276 brick contexts. Network analysis was applied to these data using a two-fold strategy: First, general similarity networks were generated, representing likely causal relationships between the contexts. Exploratory and statistical analysis of these networks enabled a data-based characterisation of the diffusion process. Then a theoretical model of this process was developed with the aim of simulating the observed data. By comparing model simulations with observed data, the model could be improved step by step. The startingpoint for constructing the model was the assumption that different categories of people contributed differently to the diffusion process. In this paper the underlying principles and main results of the modelling will be presented, together with a possible interpretation of these results. It is argued that a shift in decision-making within building industry and a greater reliance on technical expertise might have had a key role in promoting the diffusion of some architectural innovations.
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| 50. |
- Gerding, Henrik
(författare)
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The tomb of Caecilia Metella: tumulus, tropaeum and thymele
- 2002
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The present thesis constitutes a close study of a single architectural monument, the tomb of Caecilia Metella. This is a well-preserved cylindrical tomb situated on the Via Appia outside Rome, and it is generally associated with sepulchral buildings of the traditional tumulus type. An inscription reveals that the occupant of the grave was a noble woman belonging to one of the most prestigious families in late Republican Rome. The principal aim of the study is to understand the ideas and intentions behind the design and layout of the building in question, with a particular focus on the role of the commissioner. As an initiatory step the remaining structure was subjected to a close investigation, including three-dimensional documentation and computer modelling, whereby the presence of a number of architectural oddities could be established. The unique internal layout of the tomb in particular demonstrates the complexity of the building program and indicates the use of spatial concepts usually not found in Roman sepulchral architecture. In order to facilitate the interpretation of these traits comparative architectural material is presented, as well as sources of other kinds (a limited chronology of punctuation marks was constructed), but the monument itself remains at the centre of the investigation. Through a series of analyses (formal, typological, spatial and historical) of different aspects of the building, a possible explanation for the exact meaning and significance of both the external and internal layout is arrived at, and the monument is set against the background of its historical context. The dissertation concludes that the commissioner of the tomb most likely was the son of Caecilia Metella, Marcus Licinius Crassus (cos. 30 BC), and that the sepulchre was probably erected between 30 and 20 BC. Furthermore, it outlines how the tomb was deliberately used by the commissioner for his own propagandistic purposes. Thus, the monument acted as a tropaeum of the military achievements of Crassus and his ancestors. This circumstance hints at the Roman practice of combining several, partly interrelated, spectacles (e.g. funeral games and triumphal celebrations) in order to obtain a greater effect. It is also suggested that the internal arrangement can be recognised as an architectural manifestation of a religious spatial concept – the entrance to the netherworld. Although this phenomenon originally belonged to a purely mythological imagery, the architect was able to draw on various associated concepts in order to create a physical representation of the motif. The occurrence of this representation within a sepulchral building is best explained as mirroring the personal religious affiliations of the deceased and/or the commissioner. Apart from demonstrating the close connection between a single individual and certain divinities, it may have served as a focal point for continuous cultic activities of a private character. Lacking other significant parallels the installation may tentatively be labelled as a thymele. The tomb of Caecilia Metella provides a remarkable example of the transition within Roman architecture from the late Republican to the early Imperial period, and the formation of a new architectural language.
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