| 1. |
- Flankegård, Filip
(författare)
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Supplier Involvement in Product Development: A Supplier Perspective
- 2022
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis explores the supplier perspective of supplier involvement in product development. Supplier involvement in product development is crucial for many companies to increase resource flexibility, access competence, reduce costs and time to market, among others. The existing literature focuses primarily on the customer perspective of supplier involvement, e.g., challenges and critical factors customers should consider. A few studies have focused on the supplier perspective. This research gap is addressed in this thesis by studying the conditions influencing the suppliers’ involvement in customers’ product development.This thesis explores two research questions: “What are the challenges suppliers experience when being involved in customers’ product development?”, and “What mitigating mechanisms and critical factors influence suppliers’ involvement in customers’ product development?”. The identified challenges originated [FF1] both from the customer and the supplier, indicating that both types of challenges must be focused on. The study also identified interdependencies between the challenges, implying that one challenge may lead to the occurrence of other challenges. The study suggests mitigating mechanisms to deal with the identified challenges. The identified critical factors influenced both the efficiency and effectiveness of supplier involvement in product development, e.g., lead-time, development cost, product quality, and cost. The study indicates that adopting a dual perspective and considering the challenges and critical factors for both the customer and the supplier, can support the involved supplier. The results build on findings from a case study including four SMEs.
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| 2. |
- Jalilzadehazhari, Elaheh, 1985-
(författare)
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Windows and blinds selection for enhancing subjective well-being
- 2017
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Earlier studies in the context of windows and blinds selection have mostly tried to increase the awareness regarding various effects of windows and blinds selection on subjective well-being, including their effect on visual comfort, thermal comfort, energy consumption and life cycle cost. However, the main problem is the potential conflicts between visual comfort, thermal comfort, energy consumption and life cycle cost. Increased awareness about the contradictory effect of windows and blinds selection on subjective well-being on one hand and lack of a feasible method in managing the conflicts on the other hand may bind individuals, as decision-makers, in a situation where they follow the immediate economic benefits rather than the long-term visual and thermal benefits. To solve the mentioned problem, this study analysed first the degree of the conflicts between average daylight illuminance and total energy consumption in Sweden. This decision was made due to large variation in solar elevation angle and solar intensity between summer and winter in Sweden, which has significant effects on daylight illuminance and total energy consumption. Analysing the conflicts was accomplished by developing two multivariate linear regression models for calculating average daylight illuminance and total energy consumption. Comparison and analysis of the multivariate linear regression models showed the existence of a high degree of conflicts, which makes window and blind selection a rather complex multidimensional problem. Specifying the degree of the conflicts formed a hypothesis as: “A multi criteria decision-making method increases the controllability and manages the conflicts in selecting windows and blinds”. The developed hypothesis was later tested by employing analytical hierarchy process, as widely used multi criteria decisionmaking method. The analytical hierarchy process prioritizes decision-maker’ preferences and introduces a desired trade-off solution. The results of employing analytical hierarchy process showed the capability of it in managing the conflicts among visual comfort, thermal comfort, energy consumption and life cycle cost. Finally, the application of the analytical hierarchy process was expanded by integrating it with nondominated sorting genetic algorithm-II, as an optimization algorithm. Through this integration, optimization algorithm combines windows’ and blinds’ design variables and analyses a large number of solutions, while analytical hierarchy process ranks the solutions based on decision-makers’ preferences and introduces a desired trade-off solution. The integration between analytical hierarchy process and the nondominated sorting genetic algorithm-II was presented later as a conceptual framework. The developed conceptual framework can be used for selecting windows and blinds II in both residential and commercial buildings. In selecting windows and blinds, the conceptual framework is a novel solution to the lack of a feasible method for increasing the controllability for decision-makers and obtaining a desired trade-off solution.
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| 3. |
- Johansson, Niklas, 1987-
(författare)
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On the Power of Quantum Computation: Oracles
- 2018
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Quantum computation solve some computational problems faster than the best-known alternative in classical computation. The evidence for this consists of examples where a quantum algorithm outperforms the best-known classical algorithm. A large body of these examples relies on oracle query complexity, where the performance (complexity) of the algorithms is measured by the number of times they need to access an oracle. Here, an oracle is usually considered to be a black box that computes a specific function at unit cost.However, the quantum algorithm is given access to an oracle with more structure than the classical algorithm. This thesis argues that the two oracles are so vastly different that comparing quantum and classical query complexity should not be considered evidence, but merely hints for a quantum advantage.The approach used is based on a model that can be seen as an approximation of quantum theory, but can be efficiently simulated on a classical computer. This model solves several oracular problems with the same performance as their quantum counterparts, showing that there is no genuine quantum advantage for these problems. This approach also clarifies the assumptions made in quantum computation, and which properties that can be seen as resources in these algorithms.
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| 4. |
- Davoodi, Anahita, 1979-
(författare)
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Lighting simulation for a more value-driven building design process
- 2016
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Concerns about global warming are increasing, hence, the urgency to cut carbon emissions. Reducing energy consumption, including lighting energy, is seen as the primary solution. Yet, solving the environmental factor should not come at the cost of other pillars of sustainable development. Rather, maximizing the total value of the building should be the focus. Maximizing value in the context of lighting entails improving the quality of the lighting. This study has investigated how lighting simulation could help in achieving better lighting quality. The aim of the thesis was defined as to understand the underlying architecture of lighting simulation and obtain an overview of its characteristics and applications as well as to study the use of current simulation tools.The theoretical background of lighting simulation (in the domain of Systems Engineering) was reviewed from the literature. This revealed the missing and imperfect links in the solution-to-value chain. The thesis suggests the use of a new base metric, Retinal Illuminance Map, as a solution, which in combination with black box simulation of a visual system can help repair this incomplete chain.The study of the current lighting simulation tools (Paper 1) revealed that illuminance-based metrics, luminance-based metrics, daylight availability metrics, and glare indexes are the most available performance metrics in existing lighting simulation tools. Based on usability, acceptability, availability, and previous references in the literature six software programs (Radiance, DAYSIM, Evalglare, DIALux, VELUX, and VISSLA) were selected and compared. It was found that no single tool could meet all the needs of a designer, hence, simulation tool(s) should be selected (or combined) according to the requirements of project goals and the stage of design.Building on these studies, applications of lighting simulation were identified and compiled in relation to different aspects, including performance metrics, stages of design, optimization, model integration, BIM, and parametric modeling.To obtain first-hand information about lighting designers’ experience, an online survey was conducted in Sweden (Paper 2). The results showed that lighting simulation programs were widely (90%) used in Sweden for analysis and/or rendering purposes. The majority of lighting designers considered both daylight and artificial light in their design. Factors such as ease-of use, simulation time and training had more weight than accuracy and the diversity of metrics in practitioner’s eyes. Surrogate modeling was identified as a solution for speeding up simulation time, which would also enable exploration of design solution space especially in the early design stage.
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| 5. |
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| 6. |
- Jason, Peter, 1987-
(författare)
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Comparisons between classical and quantum mechanical nonlinear lattice models
- 2014
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In the mid-1920s, the great Albert Einstein proposed that at extremely low temperatures, a gas of bosonic particles will enter a new phase where a large fraction of them occupy the same quantum state. This state would bring many of the peculiar features of quantum mechanics, previously reserved for small samples consisting only of a few atoms or molecules, up to a macroscopic scale. This is what we today call a Bose-Einstein condensate. It would take physicists almost 70 years to realize Einstein's idea, but in 1995 this was finally achieved.The research on Bose-Einstein condensates has since taken many directions, one of the most exciting being to study their behavior when they are placed in optical lattices generated by laser beams. This has already produced a number of fascinating results, but it has also proven to be an ideal test-ground for predictions from certain nonlinear lattice models.Because on the other hand, nonlinear science, the study of generic nonlinear phenomena, has in the last half century grown out to a research field in its own right, influencing almost all areas of science and physics. Nonlinear localization is one of these phenomena, where localized structures, such as solitons and discrete breathers, can appear even in translationally invariant systems. Another one is the (in)famous chaos, where deterministic systems can be so sensitive to perturbations that they in practice become completely unpredictable. Related to this is the study of different types of instabilities; what their behavior are and how they arise.In this thesis we compare classical and quantum mechanical nonlinear lattice models which can be applied to BECs in optical lattices, and also examine how classical nonlinear concepts, such as localization, chaos and instabilities, can be transfered to the quantum world.
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| 7. |
- Johansson, Cecilia
(författare)
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Högstadieungdomar skriver historia på bloggen : undervisning, literacy och historiemedvetande i ett nytt medielandskap
- 2014
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The purpose of this thesis is to study the literacy formed when a class blog is used as a tool for students studying history and explore how this particular literacy is used to generate historical knowledge. The study was conducted during the course of a project in which ninth-grade students contributed entries to a common blog in the form of a diary written by individuals who experienced the Second World War. Its three major objectives were to study the students' perception of the blog in relation to their gender and level of historical knowledge; how they and their teacher esta-blished and used the formed literacy; and how the students related to this in the production of historical knowledge.In analyzing the results, a concept of literacy was used based on seven writing practices all linked to the new medium and history education. The study was based on a questionnaire, interviews and various student texts. In order to perform a content analysis on the study results a theoretical framework for historical conscious-ness was included. The results show that in using the writing practices a literacy characterized by colla-borative authorship was formed. The study concludes that this affects both what and how the students learn. Together they show each other that history is comprised of many small stories, not necessarily strictly coherent with the general history as told by their textbooks. Examining the students’ blog entries made a new learning process visible that enabled the enhancement of their historical consciousness.
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| 8. |
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| 9. |
- Johansson, Nicklas, 1973-
(författare)
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Control of Dynamically Assisted Phase-shifting Transformers
- 2008
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In this thesis, controllers for power oscillation damping, transient stability improvement and power flow control by means of a Controlled Series Compensator (CSC) and and a Dynamic Power Flow Controller (DPFC) are proposed. These devices belong to the group of power system components referred to as Flexible AC Transmission System (FACTS) devices. The developed controllers use only quantities measured locally at the FACTS device as inputs, thereby avoiding the risk of interrupted communications associated with the use of remote signals for control. For power systems with one dominating, poorly damped inter-area power oscillation mode, it is shown that a simple generic system model can be used as a basis for damping- and power flow control design. The model for control of CSC includes two synchronous machine models representing the two grid areas participating in the oscillation and three reactance variables, representing the interconnecting transmission lines and the FACTS device. The model for control of DPFC is of the same type but it also includes the phase shift of the internal phase-shifting transformer of the DPFC. The key parameters of the generic grid models are adaptively set during the controller operation by estimation from the step responses in the FACTS line power to the changes in the line series reactance inserted by the FACTS device. The power oscillation damping controller is based on a time-discrete, non-linear approach which aims to damp the power oscillations and set the desired power flow on the FACTS line by means of two step changes in the line reactance separated in time by half an oscillation cycle. A verification of the proposed controllers was done by means of digital simulations using power system models of different complexities. The CSC and DPFC controllers were shown to significantly improve the small-signal- and transient stability in one four-machine system of a type commonly used to study inter-area oscillations. The CSC controller was also tested for 18 different contingencies in a 23-machine system, resulting in an improvement in both the system transient stability and the damping of the critical oscillation mode.
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| 10. |
- Johansson, Nils
(författare)
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Why don’t we mine the landfills?
- 2013
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- There are many reasons to mine landfills. For example, metals are increasingly shifting location from the Earth’s crust through human society into landfills. These new mines are located closer to the market, in contrast to traditional mines in the countryside where the metals are deep inside the crust requiring huge amounts of energy to be extracted. In addition, metals in the landfill pose a potential threat to humans, nature, and the environment. Despite this, landfills are not commonly mined. Therefore, the purpose of this thesis is to answer the question, Why don’t we mine the landfills? This question has been approached by analyzing different factors, such as the resource potential, institutional conditions, and to some degree technical methods considered important in order to realize a mining operation, above as well as below ground. In addition, the potential of landfills as mines will be contrasted with other metal stocks currently mined in order to understand what drives resource extraction from some metal stocks but not others. Information was mainly gathered through interviews, document studies, and literature reviews between 2010-2013.Metals are currently extracted from the Earth’s crust, in-use as they successively turn into waste, and tailing ponds. These stocks have greater mining potential than landfills. For example, there are more metals in the Earth’s crust as well as in-use. Single tailing ponds contain more metals than landfills. Furthermore, the waste in tailings is homogeneous and has a similar composition to ore, thus similar technology already in ownership to process the ore can be used to reprocess old tailings. Landfills, on the other hand, are usually heterogeneous and contain a mix of various wastes. At the same time, there are no methods to uncover the contents of a landfill and thereby identify particularly valuable ores, which makes it difficult to estimate the resource potential of single landfills. Metals in-use are also situated in a heterogeneous environment, but through state regulation on source separation are made more homogenous and predictable.However, there are homogeneous landfills with fairly predictable content. But these landfills are not mined either, which largely can be explained by institutional conditions. Researchers, officials, legislators, and policy makers have long manifested the idea of landfills as the end station for worthless rubbish, and if landfills have any value it is negative, as a dump. For this reason, mining the landfill is a mismatch with the current strategy to isolate, cap, and close landfills and thereby becomes a challenging operation. At the same time as landfills are closed, mines are opened up with the support of the government. For example in 2010, the Swedish mining sector was subsidized with € 4 billion. This support is one of many factors that contribute to keeping the price of metals as a commodity down, which could make metal extraction from other stocks indirectly unfeasible. In addition, metals in landfills are not available on demand, although they lack a function, since landfills are owned by someone. The metals in the Earth's crust as well as in-use, on the other hand, are made available by exempting the ownership.If the demand for metals continues to increase, while being depleted in the Earth’s crust, additional sources for recycling need to be accessible. Compared to the risk associated with the schemes in outer space and the deep sea, the metals in the landfills seem less distant. However, there is no pressure today from policies to initiate something so awkward, unorthodox and “dirty” as extracting metals from landfills. The metal prices are too low and what is profitable and thus possible to mine from the Earth’s crust, i.e., reserves, is constantly redefined, with the help of governmental support through research funding of technological development and subsidization of the mining operation, which reduces costs.
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