| 1. |
- 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. |
- Mercke Odeberg, Johanna, et al.
(författare)
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UGT1A polymorphisms in a Swedish cohort and a human diversity panel, and the relation to bilirubin plasma levels in males and females
- 2006
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Ingår i: European Journal of Clinical Pharmacology. - : Springer Science and Business Media LLC. - 0031-6970 .- 1432-1041. ; 62:10, s. 829-837
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: The objective of this study was to investigate the prevalence of different polymorphisms and haplotypes associated with individual variations in pharmacokinetics and drug toxicity in the uridine-diphosphate glucuronosyl transferase (UGT) 1A gene in a Swedish cohort (248 healthy volunteers) and in 14 different ethnic groups. We also estimated UGT1A genotype-dependent glucuronidation efficiency using the endogenous substrate bilirubin as an indicator. Methods: Pyrosequencing-based genotyping assays were used to determine the different polymorphisms and haplotypes. Results: Haplotype analysis of the UGT1A1 (*1*28), UGT1A6 (*1*2), and UGT1A7(*1*2*3*4) allelic variants showed that three major haplotypes constituted 84% of the allelic variants in the cohort. We identified 15 haplotypes altogether from all groups, including previously undescribed haplotypes.Testing for the association of genotype and total bilirubin levels (nonfasting) in plasma disclosed that homozygous carriers of the TA allele, irrespective of haplotype combinations, had increased levels of bilirubin compared with noncarriers, but a gender-associated difference was observed. Conclusions: In a Swedish cohort, several genetic variants in the UGT1A gene are common, but prevalence in a population may differ because of ethnicity. A phenotype based on bilirubin levels has limitations in serving as an indicator of pharmacogenetic differences in glucuronidation due to the influence of gender. Because of possible substrate overlap regarding different UGT1A isoforms, determination of haplotypes of potential cis-acting polymorphisms in the UGT1A gene should be considered in pharmacogenetic association studies regarding drugs that undergo glucuronidation.
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| 3. |
- Williamsson, David
(författare)
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On integrated modularization for situated product configuration
- 2019
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Road transports face increasing societal challenges with respect to emissions, safety, and traffic congestion, as well as business challenges. Truck automation, e.g. self-driving trucks may be utilized to address some of these issues. Autonomous transport vehicles may be characterized as Cyber-Physical Systems (CPS). A drawback is that CPS significantly increase technical complexity and thus introduce new challenges to system architecting.A product architecture is the interrelation between physical components and their function, i.e. their purpose. Product architectures can be categorized as being modular or integral. The main purpose of a modular architecture is to enable external variety and at the same time internal commonality. Products with a modular architecture are configured from predesigned building blocks, i.e. modules. A stable module, which is a carrier of main function(s) has standardized interfaces, is configured for company-specific reasons, which means it supports a company-specific (business) strategy.In this thesis, the present state at the heavy vehicle manufacturer Scania, concerning product architecting, modularization, product description and configuration is investigated. Moreover, a new clustering based method for product modularization that integrates product complexity and company business strategies is proposed. The method is logically verified with multiple industrial cases, where the architecture of a heavy truck driveline is used as a test bench. The driveline contains synergistic configurations of mechanical, electrical and software technologies that are constituents of an automated and/or semi-autonomous system, i.e. the driveline may be characterized as a CPS. The architecture is analyzed both from technical complexity and business strategy point of view. The presented research indicates that a structured methodology which supports the development of the product architecture is needed at Scania, to enable control of the increasing technical complexity in the Cyber-Physical Systems. Finally, configuration rules are identified to be highly important in order to successfully realize a modular product architecture. A drawback with this approach is that the solution space becomes hard to identify, therefore a complete and flexible product description methodology is essential. The results from the case studies indicate that clustering of a Product Architecture DSM may result in a modular architecture with significantly reduced complexity, but with clusters that contain conflicting module drivers. It is also identified that the new modularization methodology is capable of identifying and proposing reasonable module candidates that address product complexity as well as company-specific strategies. Furthermore, several case studies show that the proposed method can be used for analyzing and finding the explicit and/or implicit, technical as well as strategic, reasons behind the architecture of an existing product.
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| 4. |
- Williamsson, David, 1990-
(författare)
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On integrated modularization in heavy-duty truck architecting
- 2021
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Road transports face increasing challenges with respect to safety, legislations on lower emissions and traffic congestion, as well as numerous business challenges related to paradigm shifts in technology, tightened delivery times and cost constraints. Combination of truck electrification and automation may be utilized to address some of these issues. Electrified and autonomous transport vehicles may be characterized as Cyber-Physical Systems (CPS). A drawback with CPS is the extensive increase of technical complexity, which introduce new challenges to Systems Engineering (SE). The added complexity is preferably targeted in the product architecting development stage of SE. Product architecting involves conceptual system design, module identification (clustering) and product layout design. A product architecture is the interrelation between physical components and their function, i.e. their purpose. Product architectures can be categorized as being modular, hybrid or integral. A modular architecture is a strategic means to deliver external variety and internal commonality. Modular subsystems enable concurrent development and modularization is, thus, a structured method to manage technical complexity. In this thesis, a new clustering-based methodology and process for heavy-duty truck modularization that integrates technical complexity, company business strategies and physical interference is proposed. The main hypothesis behind the presented research is that computer-based product architecture clustering analysis benefit from a quantitative complexity measure, as well as means to represent (model) and communicate product architecture related complexity. A variety of industrial cases of heavy-duty truck subsystems are used to describe the proposed methodology and to verify its performance, i.e. how well the proposed methodology and process supports the SE process. All investigated subsystems contains synergistic configurations of mechanical, electrical and software technologies, i.e. they may be characterized as CPS. The presented research concludes that the proposed modularization methodology and process is capable of supporting the SE process by improving the quality of the module identification stage, by adding business strategies and physical interference to product architecture clustering. Moreover, it is confirmed that the new methodology is both scalable and flexible, allowing the consequences of different architectural trade-offs to be analyzed independently or combined depending on purpose. Furthermore, the newly developed architectural representations showed to make architectural discussions in general and modularity discussion in particular with and between domain experts efficient. Finally, the case studies clearly shows that the clustering results depend on the relative weights of the different types of component relations that are represented in the product architecture DSM (Design Structure Matrix). However, the importance of these weights are reduced when multiple business strategic and physical interference constraints are introduced.
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