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- Börjesson, Fredrik, 1965-
(författare)
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Approaches to Modularity in Product Architecture
- 2012
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Modular product architecture is characterized by the existence of standardized interfaces between the physical building blocks. A module is a collection of technical solutions that perform a function, with interfaces selected for company-specific strategic reasons. Approaches to modularity are the structured methods by which modular product architectures are derived. The approaches include Modular Function Deployment (MFD), Design Structure Matrix (DSM), Function Structure Heuristics and many other, including hybrids. The thesis includes a survey of relevant theory and a discussion of four challenges in product architecture research, detailed in the appended papers. One common experience from project work is structured methods such as DSM or MFD often do not yield fully conclusive results. This is usually because the algorithms used to generate modules do not have enough relevant data. Thus, we ask whether it is possible to introduce new data to make the output more conclusive. A case study is used to answer this question. The analysis indicates that with additional properties to capture product geometry, and flow of matter, energy, or information, the output is more conclusive. If product development projects even have an architecture definition phase, very little time is spent actually selecting the most suitable tool. Several academic models are available, but they use incompatible criteria, and do not capture experience-based or subjective criteria we may wish to include. The research question is whether we can define selection criteria objectively using academic models and experience-based criteria. The author gathers criteria from three academic models, adds experience criteria, performs a pairwise comparison of all available criteria and applies a hierarchical cluster analysis, with subsequent interpretation. The resulting evaluation model is tested on five approaches to modularity. Several conclusions are discussed. One is that of the five approaches studied, MFD and DSM have the most complementary sets of strengths and weaknesses, and that hybrids between these two fundamental approaches would be particularly interesting. The majority of all product development tries to improve existing products. A common criticism against all structured approaches to modularity is they work best for existing products. Is this perhaps a misconception? We ask whether MFD and DSM can be used on novel product types at an early phase of product development. MFD and DSM are applied to the hybrid drive train of a Forwarder. The output of the selected approaches is compared and reconciled, indicating that conclusions about a suitable modular architecture can be derived, even when many technical solutions are unknown. Among several conclusions, one is the electronic inverter must support several operating modes that depend on high-level properties of the drive train itself (such as whether regeneration is used). A modular structure for the electronic inverter is proposed. Module generation in MFD is usually done with Hierarchical Cluster Analysis (HCA), where the results are presented in the form of a Dendrogram. Statistical software can generate a Dendrogram in a matter of seconds. For DSM, the situation is different. Most available algorithms require a fair amount of processing time. One popular algorithm, the Idicula-Gutierrez-Thebeau Algorithm (IGTA), requires a total time of a few hours for a problem of medium complexity (about 60 components). The research question is whether IGTA can be improved to execute faster, while maintaining or improving quality of output. Two algorithmic changes together reduce execution time required by a factor of seven to eight in the trials, and improve quality of output by about 15 percent.
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| 2. |
- Digard, Helena, et al.
(författare)
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Determination of Nicotine Absorption from Multiple Tobacco Products and Nicotine Gum
- 2013
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Ingår i: Nicotine & Tobacco Research. - : Oxford University Press (OUP). - 1469-994X .- 1462-2203. ; 15:1, s. 255-261
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Tidskriftsartikel (refereegranskat)abstract
- Snus is a smokeless tobacco product traditionally used in Scandinavia and available in pouched or loose forms. The objective of this study was to determine nicotine absorption for current pouched and loose snus products in comparison with a cigarette and an over-the-counter nicotine gum. We conducted an open-label, randomized, 6-way, crossover study involving 20 healthy snus and cigarette users. One of 6 products (2 pouched snus, 2 weights of loose snus, a cigarette, and a nicotine gum) was administered at each of 6 visits. Blood samples were taken at intervals over 120 min and sensory perception assessed by questionnaire. For the 4 smokeless tobacco products and the nicotine gum, blood plasma levels of nicotine were ranked according to total nicotine content as follows: loose snus (27.1 mg nicotine) > pouched snus (14.7 mg nicotine) > loose snus (10.8 mg nicotine) = pouched snus (10.7 mg nicotine) > nicotine gum (4.2 mg nicotine). The area under the plasma concentration-time curve (AUC) and maximum plasma concentration (C-max) of nicotine ranged from 26.9 to 13.1 ng.h/ml and 17.9 to 9.1 ng.h/ml, respectively across all the products. Nicotine was absorbed more rapidly from the cigarette but systemic exposure was within the range of the smokeless tobacco products (AUC = 14.8 ng.h/ml; C-max = 12.8 ng.h/ml). This study has generated new information on comparative nicotine absorption from a cigarette, loose snus, and pouched snus typical of products sold in Scandinavia. The similar nicotine absorption for 1 g portions of loose and pouched snus with approximately 11 mg of nicotine indicate that absorption kinetics were dependent on quantity of tobacco by weight and total nicotine content rather than product form.
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| 3. |
- Fritz, Örjan, et al.
(författare)
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Bjurkärr – en småländsk bokskog med unika lavar och svampar.
- 2014
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Ingår i: Svensk Botanisk Tidskrift. - 0039-646X. ; 108:3–4, s. 2-18
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Tidskriftsartikel (refereegranskat)abstract
- The old beech forest (250–300 yr) at Bjurkärr (core area 30 ha) in the province of Småland, S Sweden, was surveyed for epiphytic lichens of conservation concern in 1993–94. Several rare red-listed lichens were recorded, many with large populations. In 2011 the most endangered lichens were resurveyed due to the incorporation of Bjurkärr in the forthcoming national park of Lake Åsnen. Most species of the 1993–94 survey were rediscovered, whereas some apparently had vanished as a result of substrate decomposition. In addition, ten more red-listed lichens were recorded in 2011, e.g., Arthonia arthonioides and Collema fragrans. We also recorded Biatora ligni-mollis, not previously reported from Sweden. In all, 39 red-listed lichens are currently known from the area. Few areas in Sweden host such a large number of red-listed epiphytic lichens. In addition, the wood-inhabiting fungi on beech logs and snags were surveyed in 2011. The content of dead wood was high. A large number of red-listed or otherwise interesting wood-inhabiting fungi were recorded, e.g., Hericium erinaceus. Eleven fungal indicator species for valuable beech forests in Europe were recorded, the highest number for any Swedish beech forest. Factors explaining the high number of species of conservation concern include the long continuity of old, often slow-growing and damaged trees, the favourable geographical position in south Sweden, the suitable microclimate caused by the large neighboring lake and the exemption from modern forestry.
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