| 41. |
- Mishra, Madhav, 1980-
(författare)
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Prognostics and Health Management of Engineering Systems for Operation and Maintenance Optimisation
- 2018
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Prognostics and health management (PHM) is an engineering discipline that aims to maintain system behaviour and function and ensure mission success, safety and effectiveness. Prognostics is defined as the estimation of remaining useful life. It is the most critical part of this process and is a key feature of maintenance strategies since the estimation of the remaining useful life (RUL) is essential to avoiding unscheduled maintenance. Prognostics is relatively immature compared to diagnostics, and a challenging task facing the research community is to overcome some of the major barriers to the application of PHM technologies to real-world industrial systems. This thesis presents research into methods for addressing these challenges for industrial applications. The thesis work focuses on prognostic approaches for three different engineering systems with different characteristics in terms of the prognostics of operation and maintenance aspects. The aim of this thesis is to facilitate better operation and maintenance decision making. The main benefits of prognostics are in anticipating future failures to increase uptime, implementing dynamic maintenance planning toward decreasing total costs and decreasing energy consumption. Therefore, there is a need for methods that can be used in these cases to classify the health states and predict the remaining useful life of assets. The studied engineered systems in this thesis are railway tracks, batteries and rolling element bearings.In a railway system, the track geometry has to be maintained to provide a safe and functional track. Therefore, track degradation of ballasted railway track systems has to be measured on a regular basis to determine when to maintain the track by tamping. Tamping aims to restore the geometry to its original state to ensure an efficient, comfortable and safe transportation system. To minimise the disruption introduced by tamping, this action has to be planned in advance. Track degradation forecasts derived from regression methods are used to predict when the standard deviation of a specific track section will exceed a predefined maintenance or safety limit. In this thesis, a particle-filter-based prognostic approach for railway track degradation for railway switches is proposed. The particle-filter-based prognostic will generate a probabilistic prediction result that can facilitate risk-based decision making.Li-ion batteries are another important components in engineering system and battery life prediction matters. Li-ion batteries are commonly used in a wide range of consumer electronic devices, electric vehicles of all types, military electronics, maritime applications, astronaut suits, and space systems. Many critical operations depend on such batteries as a reliable power source. It is therefore important for the user to get an accurate estimate of the battery end of discharge because an unforeseen discharge of a battery could have catastrophic consequences. To address this issue, a Bayesian hierarchical model (BHM)-based prognostics approach was applied to Li-ion batteries, where the goal was to analyse and predict the discharge behaviour of such batteries with variable load profiles and variable amounts of available discharge data. The BHM approach enables inferences for both individual batteries and groups of batteries. Estimates of the hierarchical model parameters and the individual battery parameters are presented, and dependencies on load cycles are inferred. The operational and reliability aspects, end of life (EoD) and end of life (EoL), are studied; it is shown that predictions of the EoD can be made accurately with a variable amount of battery data. Without access to measurements, e.g., predicting performance of a new battery, the predictions are based only on the prior distributions describing the similarity within a group of batteries and their dependency on the load cycle. A discharge cycle dependency is identified helping with estimation of battery reliability.Batteries have become a very important engineering system, rotating machines have played an important role, possibly the most important role, in the field of engineering. They have been used to drive the industrialisation of the world.For rotating machinery, rolling element bearings are a vital component and have several failure modes. Hence, there is significant need to monitor the health of bearings and detect degraded states and upcoming failures as early as possible to avoid serious accidents and equipment failure. For rolling element bearings, an investigation in using FEM models for estimating bearing forces from acceleration measurements was conducted. This study was performed at a paper mill where a bearing monitoring system was installed. The purpose of the study was to feed the bearing rating life L10 (a bearing life length calculation) with estimations of the dynamic bearing forces to continuously update the L10 calculation by generating a dynamic L10. In a second study for bearing lifetime prediction, a Bayesian hierarchical modelling (BHM) approach , which includes different data sources, such as enveloped acceleration data, in combination with degradation models and prior distributions of other parameters, was developed, in which the bearing rating life calculation can be included. The proposed prognostics methodology can be used in cases where there is less or noisy data. The above approach can even be used in cases whereby there is no prior knowledge of the system or little measurement data on the conditions. The presented BHM approach can also be used to predict the remaining useful life (RUL) of bearings both in situations in which the bearing is considered to be in a healthy state and in situations after a defect has been detected.
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| 42. |
- Nilsson, Jens, Doktor, 1982-
(författare)
-
What logics drive the choices of public decision-makers?
- 2018
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis explores what logics drive the decisions of public decision-makers. More specifically, and drawing on new institutional theory, this topic is investigated from the perspective of how institutions, i.e. the formal and informal patterns of rules and practices, influence public decision-makers. New institutionalism has a variety of ideas on how this decision-making occurs and recent research in this tradition emphasizes the importance that context has for the empirical support of these ideas. At the same time, studies exploring, contrasting and converging new institutional ideas, and how these vary depending on context i.e. their conditionality, are lacking. In this thesis, I set out to address this knowledge gap and, moreover, to examine the role of personal values for the new institutional ideas on how institutions affect the public decision-makers. Personal values have not been emphasized in new institutional studies but successfully explained decision-making from other perspectives. By adding this dimension, I seek to explore whether individual factors, in this case the personal values the public decision-makers bring with them into the institutional context, affect the way they make decisions. Consequently, the aim of this thesis is to explore what decision-making logics that are at play among public-decision-makers and how this varies depending on context and personal values. This exploration is conducted by deriving and testing hypotheses on decision-making, from rational choice institutionalism and sociological institutionalism, in two different contexts, parliaments and collaborative management, within the same national arena. Parliaments have a homogenous composition of actors, i.e. politicians, whereas collaborative management arenas are constituted by the inclusion of both public and private actors in decision-making, resulting in a more heterogeneous composition. Through a study of local parliaments and wildlife conservation committees (a form of collaborative management on the regional level) in Sweden, the aim of the thesis is fulfilled by survey and interview analyses of decision-making in regards to different policy issues. The results show that there are different decision-making logics at play in the parliamentary case compared with the collaborative management case. Further, personal values influence the decision-making logics among the public decision-makers. The implications of these results are, firstly, that the conditionality of new institutionalism, as suggested in earlier research, is empirically prevalent in the studied cases and, secondly, that personal values play a role for what decision-making logics that are at play. Further research is encouraged to delve deeper into the results, preferably through qualitative studies that could complement the primarily quantitative focus of this thesis, and through studies of other national contexts than Sweden.
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| 43. |
- Nilsson, Lino, 1988-
(författare)
-
Nitrogen-cycling tracing methods : Case studies at cold-climate mine sites in northern Sweden
- 2018
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- High nitrogen effluents from mine sites is an environmental issue which has received relatively little attention historically. In recent years a number of studies have showed the environmental effects of high nitrogen discharge to natural water bodies, which include local eutrophication, high risk of acute reducing conditions and changed species composition in the receiving waters. Apart from the direct environmental effects of high nitrogen discharge some forms of nitrogen can be directly toxic- ammonia and nitric gas for instance, and some can be indirectly toxic, for instance nitrate which causes methemoglobinemia in infants if ingested.This thesis shows how the developed nitrogen tracing methods can be applied in complex water transport systems such as in a mining environment. Two main study sites were used in this thesis, the LKAB iron mine at Kiruna and the Aitik copper mine at Gallivare operated by Boliden Mineral AB. The nitrogen tracing methods used in this study are stable isotope analysis, combined nitrogen and oxygen isotope analysis, source partitioning using linear combination of sources, numerical analysis using kinetic nitrogen reaction rates, numerical model verification using stable nitrogen isotopes, and Bayesian statistical models to estimate nitrogen concentrations. The study also demonstrates an experimental method of reducing nitrogen concentrations in the mining pond at the LKAB Kiruna site. The nitrogen reducing method was tested in a small scale mesocosm experiment at the Kiruna site in northern Sweden, where a nitrogen reduction rate of around 0.25 - 0.5% total nitrate per day could be achieved.The nitrogen treatment method consists of fertilising the pond system with small amounts of bioavailable phosphorus. Phosphorus is generally the limiting factor for primary production and in the studied mining systems which have high nitrogen concentrations the phosphorus is assimilated into organic matter almost immediately after fertilisation. The phosphorus is assimilated into phytoplankton (algae) which then settles and is used as a carbon source during anaerobic decomposition (denitrification). The denitrification reaction reduces nitrate into nitrogen gas. This would reduce the nitrogen release from mine sites significantly, since nitrate is the dominant form of nitrogen at the two studied mine sites.Concluding the thesis is a 2.5D model which couples a numerical kinetic nitrogen model with a hydrodynamic model. The hydrodynamic model was the Shallow Water Equations (SWE) model that incorporates wind turbulence, inlets, and outlets as source terms for the water velocities. The two models are coupled via velocity, where the nitrogen model couples via chemical mixing and fluxes are calculated from the water velocities in each model cell. The results of this thesis suggests that nitrogen release from the the Kiruna clarification pond could be reduced significantly via the use of phosphorus fertilisation. This is due to an increased denitrification rate in the pond, and the fact that much of the discharge water from the pond system is recirculated back into the mineral processing plants. The recirculation essentially means that the nitrate in the mine water will have quite a long retention time before being passed out the receiving waters.Although the presented nitrate reduction approach showed promising reduction rates, the potential risk of eutrophication in the receiving waters is high, as the discharge water will contain high levels of nitrogen and potentially also phosphorus. The transport pathways and possible natural attenuation of phosphorus must be thoroughly investigated before the presented nitrate reduction method can be implemented at full scale in mine ponds.
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| 44. |
- Nygren, Magnus
(författare)
-
Safety management on multi-employer worksites : Responsibilities and power relations in the mining industry
- 2018
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The focus of this thesis is on the division of legal responsibilities for occupational safety management on multi-employer worksites in the mining industry. The empirical basis is a study conducted between 2013 and 2016 consisting of interviews and observations focusing on primarily managers, supervisors, coordinators and safety specialists from a Swedish mining company and a number of its contractors. Besides this, interviews were also conducted with an inspector from the Swedish Work Environment Authority (SWEA) and workshops were arranged involving industry representatives. Additionally, a document analysis was performed focusing on work organization, safety and regulatory matters. The theoretical framework focuses mainly and broadly on the consequences of inter-organizational complexity and power relations between organizations and between social actors.The results show that three key aspects characterize the division of legal responsibilities for safety management: 1) the main responsibility for managing safety is employer-specific and cannot be shared (e.g. between two separate companies) and entails specific formal tasks that must be performed, 2) everyone involved on multi-employer worksites has an extended duty to communicate and cooperate across companies in safety-related matters, and 3) the responsibility for coordinating work and broader safety measures is connected to one specific employer, usually the main client company itself by virtue of the work being conducted within its facilities. Although seemingly straight-forward in the legal demands being placed on specific actors, the matter of the division of responsibilities and what they should entail in practice had been a specific focus area for the mining company, as well as for the mining industry trade association and SWEA from an even broader perspective. The mining company had also taken a number of initiatives with the ambition to clarify these issues on their own multi-employer worksites in accordance with the legal requirements. As for the relations between the mining company and the contractors, these were characterized by an asymmetry of power with a difference between being affiliated to the company or a contractor in terms of the status and rights each affiliation entailed. This ultimately had an impact on contractor managers’ and supervisors’ ability or willingness to communicate with the client on safety-related issues.The conclusions of the thesis are divided into two main themes. The first theme, undermined conditions for employer responsibility, highlights that the main employer responsibility for managing safety may become eroded on multi-employer worksites, something that can be viewed from three distinct but interrelated perspectives: 1) the core-periphery structure characterizing multi-employer worksites, 2) how the different legal responsibilities relate to each other and the power asymmetry between organizations, and 3) the relations between the social actors involved in formal safety management in practice. The second theme, client company initiatives and blurring boundaries, underlines that the ambition of the mining company to clarify responsibilities meant that other issues related to power relations became downplayed or unaddressed. The dominant position that the company and, by extension, its managers, coordinators, etc., typically had also led to them occasionally intervening in the internal processes of the contractors, highlighting the importance of considering the consequences of blurred organizational boundaries due to longstanding outsourcing arrangements.An overall conclusion can be drawn that the dynamic, unfolding relations between the client and its contractors complicate the division of and adherence to legal responsibilities for safety management. This is a particular challenge facing policy and regulatory development going forward, not only in relation to the mining industry but on multi-employer worksites in general where workplace safety is especially important to consider.
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| 45. |
- Padyab, Ali
(författare)
-
Exploring Impacts of Secondary Information Use on Individual Privacy
- 2018
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Information collected from individuals via online social networks and Internet of things devices can be used by institutions and service providers for different business purposes to tailor and customize their services, which is defined as secondary use of information. Although the literature on secondary use is well developed, prior studies have largely focused on direct use of information such as those instances of information use that do not stem from data mining. Advances in data mining and information-processing techniques facilitate discovery of customers’ and users’ behaviors and needs. Research shows that individuals’ behavior can be inferred with high accuracy from their shared information, which may in turn jeopardize privacy. A recent scandal of Cambridge Analytica using about 87 million Facebook profiles to target those users with customized micro-targeted political ads has created public outrage and raised criticisms of secondary use. Given this background, the purpose of this thesis is to explore impacts of organizations’ and service providers’ secondary use of personal information in order to draw conclusions related to how individuals’ attitudes are formed and what role secondary use plays in managing privacy.This research investigates user awareness and attitudes towards potential secondary uses of information. To pursue this, a multi-method qualitative approach using a descriptive questionnaire with 1000 European citizens and a total of 10 focus groups with 43 participants was employed. A qualitative content analysis using both inductive and deductive approaches was conducted to analyze the results. The conceptual framework employed in this thesis was genres of disclosure.The research results suggest that user awareness of the potential for indirect personal information disclosure was relatively low. It was consequently found that participant attitudes toward privacy and disclosure shifted from affective to cognitive when they experienced firsthand the potential inferences that could be made from their own data. Generally, the participant users only considered their direct disclosure of information; through observing potential indirect inferences about their own shared contents and information, however, the participants became more aware of potential infringements on their privacy.The study contributes to information privacy and information systems literature by raising understanding of the impacts of secondary use, in particular its effects on individual privacy management. In addition, this thesis suggests that information privacy is affected differently by direct and indirect uses. Its contribution to information privacy research is to complement previous methodological approaches by suggesting that if users are made aware of indirect inferences that can be made from their content, negative affective responses decrease while cognitive reactions increase through the processing of information related to their disclosure genres. The reason is that indirect use of information inhibits the negotiation of information privacy boundaries and creating unresolved tensions within those boundaries. Cognitive awareness of inferences made to individual information significantly affects the privacy decision-making process. The implication is that there is a need for more dynamic privacy awareness mechanisms that can empower users by providing them with increased awareness of the indirect information they are sharing.
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| 46. |
- Patil, Sandeep, 1983-
(författare)
-
Enhanced engineering of component-based industrial automation systems using formal methods
- 2018
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Industrial automation is facing challenges related to a manufacturing change from mass pro-duction to mass customization. As a result, the focus of automation has been shifting to flexi-bility, reconfigurability and safety assurance resulting in a new class of systems that is heavilymodular. We call this new class of systems as Component-Based industrial Automation Sys-tems (CBAS).Given the current challenges and shift in focus, the current engineering practices and meth-ods need to be changed or upgraded. One of these practices is software verification and valida-tion (V&V) techniques. Simulation is one of the well-known V&V techniques used currentlyin CBAS. Simulation is performed by building simulation models for the physical process,for example, simulation using Matlab. However, development of simulation models is time-consuming and does not guarantee 100% validation of the automation control software makingjust simulation inadequate for CBAS. To address this problem, formal verification has beenconsidered as a proper complementary V&V technique. Discrete state model checking is oneof such approaches, which is the process of automatically verifying whether a set of desiredformal specifications is satisfied over the target system model. While model checking is com-putationally resource hungry, it has been successfully used in other adjacent areas of computersystems engineering, such as hardware design, proving its ability to handle problems of rea-sonably large complexity. This suggests that model checking can be applied in the industrialautomation domain, and there has been an impressive number of works towards this goal.Despite moderate successes and promises the reality is that formal techniques are rarelyused in the development practice by industrial automation engineers. It seems that the existingtools and methods do not fit into the current Software Development Life Cycle (SDLC) of au-tomation systems engineering. This thesis first looks at current state of art with comprehensiveliterature review, identifying 3 main challenges for lack of industrial adoption of formal verifi-cation. The thesis then presents various formal method approaches to address these challenges.The main contribution of the thesis is a method for the formal verification of IEC 61499 func-tion block applications using Abstract State Machines (ASM) and model checking. A formaldescription for main artifacts of the standard is presented in the thesis. Further, ASM rules fortranslation for function blocks to the input format of the SMV model checker is presented. Inthis way, the proposed verification method enables the formal verification of the IEC 61499control systems.As results, the thesis presents an application of this framework to industrial automation usecases to check for functional and non-functional requirements. It also presents use cases wherethe proposed framework is used for verifying portability of IEC 61499 based control applica-tions across different implementation platforms compliant with the IEC 61499 standard.
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| 47. |
- Perez Rafols, Francesc, 1990-
(författare)
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Two-scale stochastic modelling and analysis of leakage through metal-to-metal seals
- 2018
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- A seal is a commonly used machine element whose function is to preventthe flow of a fluid from a high to a low pressure region. Metal-to-metalseals, in particular, are used whenever extreme conditions prevent theuse of less expensive rubber seals. Situations where such extreme condi-tions may be encountered are found, for example, in oil wells and nuclearpower plants. In such applications, the failure of a metal-to-metal sealcan become catastrophic, as it might mean the leakage of hazardousfluids to the environment. In order to minimize the risk, it is critical tounderstand the mechanisms controlling the seal’s performance and,if possible, be able to predict capability to prevent leakage on before-hand. Not surprisingly, the surface topography plays a crucial role hereand therefore requires careful consideration when conducting studies ofthis kind. Indeed, it has been shown that even very small details in thetopography (of size of the order of micrometres) can have a large effecton the performance of the whole seal (of size of the order of centimetresor larger). Another complicating factor is the topography’s stochas-tic nature, which makes even the identification of the relevant detailschallenging. Modelling is, in this context, a desirable approach, as itprovides the possibility to easily zoom in those fine details as well asisolate individual parameters. Moreover, it can provide for a predictionon the expected leakage.This work focuses primarily on the development of a model suitablefor studying the mechanisms controlling the performance of metal-to-metal seals and to enable prediction of leakage. To accomplish this, amodel that follows a two-scale approach is proposed. More precisely,the small details in the topography are considered in a local problemconnected to a highly resolved local-scale domain, while the componentlevel features are considered in a global problem allowing for a coarsegrid discretisation of the corresponding global-scale domain. During the present work it was also found that realistic results can only be obtainedif the model explicitly considers the surface topography’s stochastic na-ture. The model was first developed for liquids and was based on theassumption of incompressible and iso-viscous flow. Further work, withthe objective to enable studies of more complex type of flow situations,resulted in a versatile transformation translating results for incompress-ible and iso-viscous to compressible and piezo-viscous fluids and viceversa. This means that, the flow of gases and other more complex fluidscan be studied by combining the model for the simplistic incompressibleand iso-viscous flow with this newfound transformation.Using the model developed, the sealing performance of metal-to-metal seals during load cycling, i.e., by gradually increasing the load toa certain value and then releasing it again, is studied. The scope of thisstudy is to assess how the plastic deformation that the metal surfacesundergoes during the loading phase can affect the leakage during unload-ing. It is shown that this results in a change of the original topographythat may lead to a better sealing performance during unloading. Themain result obtained is, however, that given the right conditions, the ap-plied load can be released considerably (even down to half of the reachedbefore starting the unloading) with only a small increase in leakage asa result. This shows the seal’s capability to prevent leakage evenif an unexpected reduction of load occurs and is therefore is a valuabledescription of the robustness of the seal.
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| 48. |
- Poelzer, Gregory A
(författare)
-
Extracting Legitimacy : Input, Throughput, and Output Legitimacy in the Mining Industry
- 2018
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Legitimacy affects questions on constitutional design, international political regimes, and specific policy sectors. Although it permeates society at various levels, legitimacy becomes particularly crucial when decisions hold long-term or permanent consequences. In democratic societies, decisions on electoral reform or constitutional amendments typically include various checks and balances to increase the legitimacy of the outcome and similarly, on a smaller scale, resource development also undergoes of series of checks and balances to improve legitimacy. I investigate one such resource development, mineral extraction, to look at key factors of input, throughput, and output legitimacy in a policy sector with long-term or permanent outcomes.If the strength of the input legitimacy (democratic, participatory quality) is high, then a deficit of output legitimacy (decisions, outcomes) can be overlooked –and vice-versa. This interpretation of legitimacy focuses on the decision-making process and the outcomes, but with the active role companies take in mining operations it becomes critical to consider the non-state actors involved in the process. To address this additional piece of this equation, throughput legitimacy is utilized to analyze the effect of relationships in policy decisions. By looking at the quality of interaction, this thesis investigates where throughput fits within the three dimensions of legitimacy in the mining sector.Using interview and survey data from Sweden and Canada, this research in this thesis addresses both theoretical and empirical issues. Theoretically, the effect of multiple actors on the policy process legitimacy of policy processes are explored. Using the input, throughput, and output legitimacy trichotomy provides a basis through which to investigate the changes engendered by different governance arrangements and their effect on legitimacy. When support for policy also depends on activity outside the formal processes of government, the implications for legitimacy change –creating a new theoretical criterion. Empirically, the qualities and factors that affect the legitimacy of a process are identified. The findings of this thesis provide insight on future process designs; understanding the relationship between participation, interaction, and outcomes inresource development processes and the factors critical to legitimacy emerges and endures.
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| 49. |
- Ramanenka, Dmitrij
(författare)
-
An Approach for Evaluation of Brick Lining's Mechanical State in Rotary Kilns
- 2018
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Production of many materials requires treatment at elevated temperatures. Calcination and sintering are some of the important heat treatment procedures which are typically performed in so-called rotary kilns. These, not very well-known treatment vessels, have a significant impact on our everyday life. Our most common materials have direct con-nection to the use of rotary kilns. Concrete−covering the vast 80 wt% of total material production in the world−consists to a large part of cement produced in a rotary kiln. Steel−by far the most produced metal−frequently starts its journey in a rotary kiln in form of iron-ore pellets. Paper−another everyday life product−is dependent on mineral lime that is typically calcinated in a rotary kiln. The importance of rotary kilns in our society cannot be doubted.The concept of a rotary kiln is rather simple. It consists of a thick cylinder-formed steel casing that, due to high process temperatures, is insulated by a refractory lining. Service conditions inside the rotary kiln are rough and the refractory lining is continuously degrading, especially pronounced in the hot zone of the rotary kiln. If the lining is significantly deteriorated and can no longer protect the casing from the heat−the production is shut-down−leading to very high production losses.Despite many improvements of rotary kilns in the past decades, there is still a gap in the knowledge regarding refractory linings during usage. Many assumptions are based on practical knowledge. One explanation to this could be the difficulty to study and observe the lining due to the large sizes of rotary kilns and high operating temperatures. Today, computers are of a great help for studying various issues without causing production delays or risking failures. However, the field of rotary kilns has stagnated on this matter and little documentation can be found regarding numerical simulations of the refractory lining for rotary kilns, especially of the thermomechanical character.The aim of this thesis work was to create a numerical model of a rotary kiln usedin iron-ore pelletizing for studying the mechanical and thermomechanical behaviour of refractory brick lining. For this, a simplified finite element model (FEM) of a rotary kiln was created and its trustworthiness verified. It was confirmed that the model gives agood response. Different tips and justifications in the creation of the model of the rotary kiln are given. Furthermore, some mechanical material tests were performed for data input into the model. Various fundamental cases were studied in cold and hot states of the rotary kiln. It was shown that critical situations affecting the brick lining could be captured in a satisfactory way. The insight into the behaviour of the brick lining with respect to various parameters opens possibilities for lowering risk of brick lining failure by an improved management of the rotary kiln.
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| 50. |
- Reim, Wiebke
(författare)
-
Towards a framework for product-service system business model implementation
- 2018
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Manufacturing companies are increasingly focused on service-led growth to gain new revenue streams and achieve sustainable competitive advantages. In this regard, offering product-service systems (PSS) is proposed as an attractive solution for manufacturing companies to achieve economic, environmental, and social benefits. More specifically, through the integration of provider and customer operations, efficiency is increased because each party focuses on its core competencies, and operations are optimized. For example, prolonged product lifetimes and increased resource utilization are part of the sustainability achievements that can be achieved through successful PSS implementation.Still, successful implementation of PSS is rare. The business model has become acommon unit of analysis in PSS and the crucial factor that may differentiate successful and unsuccessful PSS companies. Revising business models toward PSS provision and the implementation of the PSS business model is a challenging process that constitutes a major reason why companies struggle to increase the service degree of their offerings. This thesis suggests that a better understanding of tactics, risk management, service network adjustment, and activity alignment is associated with PSS business model implementation. Therefore, the purpose of this thesis is to advance the understanding of PSS business model implementation.Comprised of a cover story and five separate but interrelated articles, this dissertation explores the implementation of product-service systems business models. The results are based on a systematic literature review and four case studies with Swedish manufacturing companies. The thesis is empirical based on 107 interviews with employees from four different manufacturing companies and eight distributers of one of the case companies.This thesis contributes to the PSS literature by proposing a four-phase PSS business model implementation framework. The framework goes beyond selecting a PSS business model to also include the configuration of related tactical sets, risk identification and management, and adjustment of the delivery practices, along with activity alignment. All phases are crucial for PSS business model implementation and therefore make specific contributions by themselves. Furthermore, by applying agency theory to mitigate adverse customer behavior, this thesis contributes to the increased legitimacy of the PSS research field.
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