| 41. |
- Marti Bigorra, Anna, 1990-
(författare)
-
Customer-focused data-driven target setting
- 2019
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- To develop products through a customer-centric strategy, early stages of product development such as target setting play an important role. In the target setting stage Customer Needs (CN) are gathered and translated into Design Requirements (DR) in order to subsequently set product targets that fit cost constraints and at the same time result in high Customer Satisfaction (CS). Continuous advances in information technology create new opportunities for companies to gather information about the customer, for example, for marketing purposes, or to assess customer reactions after the launch of new products. In addition, products are becoming complex systems that are successively equipped with more software and sensors offering opportunities for collecting data on how they are used. Knowing how customers use the product enhances a company’s ability to segment customers and customize products.Despite customer information availability from different sources (sensors, social media, etc.), surveys and focus groups are considered today as the main data source to derive the set of CN statements during target setting. Further, the team’s interpretation of CNs, which are often described in abstract language, must be translated into DRs, which are described in a more technical language. Hence, the translation process of CNs into DRs is said to be subjective. To set product targets, CS sensitivity to changes in DR levels is also considered. Surveys and benchmarking data containing customer perceptions on competitors’ performance are often the main customer data input into the process. While insightful information may be obtained, surveys are costly and time consuming and only encompass a small part of the market population.The research presented in this doctoral thesis explores how customer information obtained from sensors (e.g. product usage data) and text data (e.g. from websites, open-survey questionnaires) can be factored in the target setting process before concept generation to enhance customer focus without compromising product development time. The aim is to increase designers’ awareness of target population and in turn increase the quality of the design decisions on product targets. For this purpose, a customer-focused data-driven target setting methodology is proposed. The presented methodology changes the actual target setting methodology by means of indicators and autonomous activities on those parts of the process where marketing or design decisions are needed. The proposed methodology gives the incentive for a more integrated product development where marketing and designers need to work closely. This further allows a sustainable customer information gathering strategy that strives for missing customer information that is required for setting product targets. The indicators act as feedback channels for continuous product improvement. The use of such indicators and autonomous activities highlights the potential of a more efficient, less subjective and higher-quality target setting process.
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| 42. |
- Neikter, Magnus, 1988-
(författare)
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Microstructure and hydrogen embrittlement of additively manufactured Ti-6Al-4V
- 2019
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The work of this doctoral thesis has been performed between the 24th of August 2015 to the 6th of September 2019. The general purpose of this work has been to increase the knowledge of additively manufactured Ti-6Al-4V when it comes to microstructure, texture and hydrogen embrittlement. Several additive manufacturing (AM) processes have been addressed, the main focus, however, has been on the two processes electron beam melting (EBM) and selective laser melting (SLM). The work has been performed at Luleå University of Technology and at Monash Centre of Additive Manufacturing (MCAM), which is a part of Monash University, Melbourne Australia. GKN Aerospace Engine Systems has been involved in the work as a collaborative industrial partner. Where the main interaction and support has been between GKN in Trollhättan, Sweden. GKNs facility in Filton, United Kingdom, however, has also been involved in sample production. The texture measurements using neutron time of flight (TOF) diffraction were performed in Dubna, Russia at Frank Laboratory of Neutron Physics at the Joint Institute for Nuclear Research, using the spektrometer kolitshestvennovo analiza tekstury (SKAT) instrument and in Los Alamos at Los Alamos Neutron Science Center, using the texture instrument high pressure preferred orientation (HIPPO). The interest of specifically additively manufactured Ti-6Al-4V originates from GKN Aerospace Engine Systems as they have been contracted to manufacture parts for the Ariane rockets. In aerospace, weight is of utter importance as reduced weight of the components reduce the fuel costs and makes it possible to transport increased loads. Therefore, titanium has been suggested to replace heavier metal alloys (such as nickel-based superalloys) due to titanium’s high specific strength and overall good properties. The work has been managed under the supervision of Professor Marta-Lena Antti, Professor Robert Pederson and Dr. Pia Åkerfeldt at Luleå University of Technology and by Professor Xinhua Wu and Professor Aijun Huang at MCAM. The project has been financed by three parties Space for Innovation and Growth (RIT), Nationellt Rymdtekniskt Forskningsprogram (NRFP) and the Graduate School of Space Technology. The thesis is composed of a literature review along with the appended papers that have been written throughout the duration of the project. The purpose of the literature review is to give the reader a broader knowledge and context about the theory behind the work conducted during the Ph.D. project. The thesis commences with a theoretical background about titanium, its crystal structures, microstructure, and AM. The chapter about AM is divided into three sub-chapters, explaining the two different AM sub-groups directed energy deposition (DED) and powder bed fusion (PBF). Then the chapter finalizes with explaining the benefits and drawbacks with AM. Once these subjects been explained there is a chapter explaining AM built Ti-6Al-4V. The theme of this chapter is the differences in the microstructure of AM built and conventional built Ti-6Al-4V, where phenomena like chessboard pattern and layers bands are discussed, followed by a comparative section of the mechanical properties. The chapter about AM built Ti-6Al-4V is followed by a chapter about texture where the two texture techniques electron backscattered diffraction (EBSD) and neutron (TOF) diffraction are explained. The literature review then continues with the chapters neutron tomography, hydrogen embrittlement, and fatigue crack growth. Then there is a chapter about the materials and experimental methods that have been used to perform all the experiments, then a summary of all the papers and conclusions. After the conclusions, the thesis finalizes with a chapter about possible future work and an outlook into the future of AM. In the end, the papers I to IV are appended.
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| 43. |
- Neyses, Benedikt, 1986-
(författare)
-
Surface Densification of Solid Wood : Paving the Way Towards Industrial Implementation
- 2019
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Surface densification of a piece of solid wood results in an increase in density and in hardness in the whole or a part of the densified material, and is one of the ways of improving the properties and value of low-density wood species. Despite efforts for many years, mass commercialisation of either bulk- or surface-densified wood products has not yet been achieved. Most of the previously tested densification methods have limitations in terms of processing speed and integration into the largely continuous wood processing chain, which leads to high production costs. Established methods to eliminate the set-recovery rely either on technologically complex close-system methods or on open-system methods that require relatively long periods of high energy input. For this reason, impregnation with adhesives is used in almost all commercially available densified wood products, and none of them have risen above their status of being niche products.Based on this background, three objectives for this project were formulated: (1) the development of a method for selecting the most suitable wood species for surface densification, (2) showing that surface densification can be carried out in a continuous manner at high process speeds, (3) and researching a fast open-system method to reduce the set- recovery.The method developed for selecting the most suitable wood species for surface densification was based on Lean principles, and it confirmed the suitability of previously studied wood species, such as Scots pine, spruce and poplar. In addition, several suitable alternatives from different parts of the world and from different types of forest were identified. This suggests a high potential for establishing such wood products on a global market level.Two studies using a continuous roller press showed that solid wood can be successfully surface-densified at process speeds of up to 80 m min-1, and that some defects, such as knots, are acceptable in the raw material, but the problem of set-recovery could not however be solved.A screening experiment testing different open-system approaches to reduce the set-recovery highlighted the potential of a novel method using ionic liquids as a plasticiser prior to the surface densification of solid Scots pine. The set-recovery could be reduced to 10%, with the time of high energy input being less than 10 minutes. The Brinell hardness was increased by a factor of 2.7 over that of undensified wood. A study with thermo-gravimetric analysis and digital image correlation showed that the set-recovery almost exclusively happens in the transition zone between the densified and undensified wood cells, where there is less penetration of the ionic liquids.The work accomplished in this project has successfully addressed several gaps in the field of wood densification, firstly, by employing a continuous surface densification process using a roller press, and secondly, by developing and studying a fast open-system pre-treatment with ionic liquids, which greatly reduces the set-recovery. Research will continue on a new band press, facilitating a swift transfer of knowledge between small- scale studies and the continuous surface densification of production-size wooden boards.
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| 44. |
- Nilsson, Joakim, 1989-
(författare)
-
Wireless High-Temperature Monitoring of Power Semiconductors : A Single-Chip Approach
- 2019
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Because failures in power electronic equipment can cause production stops and unnecessary damage to interconnected equipment, monitoring schemes that are able to predict such failures provide various economic and safety benefits. The primary motivation for this thesis is that such monitoring schemes can increase the reliability of energy production plants. Power semiconductors are crucial components in power electronic equipment, and monitoring their temperatures yields information that can be used to predict emerging failures.This thesis presents a system concept for wireless, single-chip, high-temperature monitoring of power semiconductors. A wireless single-chip solution is both cost effective and easy to integrate with existing power semiconductor modules. However, the concept presents two major challenges: the implementation of wireless power and communication, and the low-power design of the temperature sensors. To address these challenges, the feasibility of using on-chip coils to provide communication with and to obtain power from an external reader coil is demonstrated, and a low-power, high-temperature bandgap temperature sensor is developed.For the challenge of generating geometries of on-chip coils with high power transfer efficiencies, a gradient ascent algorithm is used to generate geometries that provide high power transfer efficiency at the frequency of interest. A theory is developed, focused on the relation between optimised coil geometries and the load requirements of an application. A cutoff-point is discovered, beyond which power delivered to the load does not increase even if the load is made lighter. Electromagnetic simulations for an on-chip coil model are presented, which show that this load-limit lies around 10 kΩ for one 350 nM process. The model is verified with measurements on manufactured devices.To generate coils which operate within a desired frequency band in which sufficient radiated energy is permitted, a methodology for tuning on-chip coils with on-chip fuses is presented. The decision to use fuses for tuning instead of transistors for this application is due a transistor's requirement of a DC supply for bias. For wireless single-chip systems, no such DC supply is available at system start-up. The methodology presented addresses the challenge of achieving high Q~factors for capacitor-fuse series connections despite the fact the fuse resistance of on-chip fuses is finite in their blown state and non-zero in their active state.A single-chip, on-chip coil solution comes with advantages such as galvanic isolation from the power device and simplicity of integration in existing modules. However, because a wireless design with a small on-chip coil will limit the amount of available power, it incurs the disadvantage of requiring a low-power design for the temperature sensor. Therefore, a design is presented of a temperature sensor consuming power in the microwatt range in the high-temperature region where it is useful for detecting incipient faults, particularly solder faults. This is achieved by compensating for leakage currents that arise in hot reverse-biased p-n junctions, which become significant at these temperatures.At high temperatures, these leakage currents can approach or even surpass the level of a circuit's quiescent current. Earlier work on leakage current compensation techniques is examined, compared to and combined with a compensation technique designed to compensate for collector-base leakage in the main bipolar pair of a Brokaw bandgap reference. Experiments show that fully analogue sensors operating at up to at least 230 °C for a sensitivity of 2 mV/°C are feasible at a power consumption around 10 µW. Such sensors would yield a resolution of 2 °C if an 8-bit analogue-to-digital converter is employed. However, the transmission of data to the transmitter coil remains future work. Furthermore, a discussion is held to address design of unimplemented system components which are needed in order to implement a complete single-chip temperature measurement system. Points discussed include high-temperature analogue-to-digital conversion, clock generation and wireless communication.
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| 45. |
- Näsström, Jonas
(författare)
-
Phenomena in wire based multi-layer laser welding and hybrid deposition
- 2019
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Several laser materials processing technologies using metal wire addition have been researched during the last decades. Especially in the field of joining, as well as in the field of Additive Manufacturing (AM), multiple major benefits have been reached, e.g. higher welding speeds and lower heat input. With laser and arc hybrid welding techniques, additional prospects become accessible. These can combine and improve both deep penetration of autogenous laser welding and gap bridging capabilities of traditional arc welding. In the field of AM, wire feed has been a much-appreciated way of supplying additional material. Reasons include clean and easy handling, high utilisation and availability. A high intensity heat source, e.g. a laser beam or an electrical arc, continuously melts a metal wire; the melt being deposited onto a substrate in one or multiple layers to generate a new surface or three dimensional structure. An alternative joining process is Narrow Gap Multi-Layer Welding (NGMLW). This technique utilises the former mentioned AM processes to fill a gap to join sheets together, instead of depositing on an open surface. NGMLW is a capable competitor to the above-mentioned joining processes due to its prospects of being able to join essentially any thickness of sheets, as long as the beam and wire can accurately reach the gap floor and a sufficient number of layers are used.In this thesis, multiple types of NGMLW, Papers A – D, and hybrid material deposition, Papers E and F, using laser and hybrid heat sources with metal wire addition have been studied. Techniques such as High-Speed Imaging (HSI), 3D and Computed Tomography (CT) scanning have been used to gain greater insight into the workings of these modern manufacturing processes. The multi-layered way of material deposition within a gap to form a welded joint and onto a surface for AM have many similarities, e.g. wire melting behaviour and melt flow.Paper A introduces the workings of NGMLW, highlighting possible welding imperfections and welded joint morphology. HSI of the process is analysed both qualitatively and quantitatively: qualitative analysis identifying possible causes for said imperfections; quantitative analysis highlighting the potential for using similar and lower frame rate camera footage for closed loop control to suppress the formation of such imperfections.In Paper B, an alternative near-vertical building strategy for NGMLW is presented and compared to its more common horizontal counterpart. This upright strategy is found to be fully capable of producing sound welded joints, sporting less than 0.3% cavities. The near-vertical welded joints also have potential for unique material properties due to their much different thermal history.Papers C and D return to the topic of horizontal NGMLW, but with resistance heating of the metal wire for easier processing, also referred to as Laser Hot-Wire Welding (LHWW). Process behaviour and the resulting morphology of welded joints are the main topics of Paper C. Theoretical reasoning for the formation of occasional centre-line cracks, relating to the shape of the melt pool during solidification, are presented. Arcing is observed in some of the experiments, although prior theory indicates that the applied wire voltage was too low for arcing to occur. This arcing phenomenon is further covered in Paper D, where HSI observations are used to correlate process parameters to arcing probability and a theoretical explanation of why arcing can occur is suggested.Papers E and F take the step out of the gap, studying the impact of laser beam augmentation in different orientations on Wire-Arc Additive Manufacturing (WAAM). Paper E focuses on a method of quantifying melt pool movement. Fluctuations of the melt pool surface decreased by more than 35% with the introduction of a laser beam to the process. Paper F analyses the generated structures, evaluating the usable portion of the “as deposited” shapes and material composition. Surface irregularities decreased by more than 50% on application of a trailing laser beam. Additional aspects relating to the resulting morphology are also presented, including observations and reasoning for surface irregularities and sloping.The knowledge gained and methods used in the presented work intertwine to form a strong insight into both laser and laser-hybrid materials processing with wire addition. They also introduce approaches for processing and quantifying HSI footage for process evaluation and improvement.
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| 46. |
- Olofsson, Alexandra, 1978-
(författare)
-
Möjlighet till aktivitet och delaktighet utanför hemmet för personer med förvärvad hjärnskada
- 2019
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Det övergripande syftet med denna avhandling var att öka kunskapen om möjlighet till aktivitet och delaktighet utanför hemmet för personer i yrkesverksam ålder med förvärvad hjärnskada (FHS).Studie I syftade till att utforska och beskriva hur personer med FHS erfar engagemang i aktiviteter utanför hemmet. Intervjuer genomfördes med åtta deltagare och data analyserades genom konstant komparativ metod. Resultatet visade att svårigheter att bearbeta intryck, fatigue, förberedelse och upplevda risker var avgörande för deras begräsningar av engagemang i aktiveter. De använde nya strategier för att möjliggöra engagemang i aktiviteter med olika konsekvenser för deras liv. Studie II syftade till att utforska och identifiera problematiska situationer relaterat till aktiviteter utanför hemmet för personer med FHS. Upprepade intervjuer och deltagande observationer genomfördes med två deltagare och genererade data som analyserades med narrativ metod. Deltagarnas berättelser speglar hur det var en ständig kamp att försöka hantera oförutsedda händelser och kontrollera olika situationer de ställdes inför när de engagerade sig i aktiviteter utanför hemmet. Vidare, hur de dragit sig tillbaka från olika platser vilket medförde att deras sociala liv begränsats och att fler aktiviteter utfördes ensam och i hemmet efter skadan. Studie III syftade till att beskriva och jämföra upplevd delaktighet på platser utanför hemmet hos personer med stroke samt relationen mellan det totalt antal platser som besöktes, funktionshindrets svårighetsgrad och sociodemografisk data. Intervjuer genomfördes med sextiotre deltagare med stroke utifrån instrumentet ACT-OUT. Data analyserades med deskriptiv statistik, icke parametriska test, ANOVA och General Linear Model (GLM). Resultatet visade att gruppen med god återhämtning besökte i genomsnitt flest antal platser följt av dem med medelsvårt och svårt funktionshinder och skillnaden mellan grupperna vara signifikant. Skillnader i besökta platser var framförallt relaterat till platser för sociala, kulturella och andliga aktiviteter samt platser för rekreation och fysisk aktivitet. Oavsett funktionhindrets svårighetsgrad önskade deltagarna besöka platser i framtiden som de förnärvarande inte besökte. Funktionshindrets svårighetsgrad och bilkörning var signifikant associerade med det totala antalet besökta platser för aktiviteter utanför hemmet. Studie IV syftade till att utforska mönster av delaktighet på platser för aktiviteter utanför hemmet och om dessa mönster var relaterade till funktionshindrets svårighetsgrad och faktorer i miljön. Intervjuer genomfördes med samma deltagare och instrument som i studie III och analyserades med deskriptiv statistik, icke parametriska test och tvåstegs klusteranalys. Av analysen framkom fem mönster av delaktighet innehållande fyra möjliggörande och hindrande aspekter; upplevt avstånd till platsen, hur frekvent platsen besöktes och hur familjär platsen samt vägen till platsen var. Resultatet visade att det endast fanns signifikanta skillnader mellan mönstren när det gällde transport till och från platsen och socialt stöd.Sammanfattningsvis bidrar denna avhandling med kunskap om de mångfacetterade ständigt föränderliga utmaningar och problematiska situationer som personer med FHS erfar vid engagemang i aktiviteter utanför hemmet. Vidare, om strategier i aktivitet som möjliggör att personer med FHS kan återuppta och/eller bibehålla aktiviteter utanför hemmet. Avhandlingen bidrar även med kunskap om samband och mönster som påverkar upplevd delaktighet på platser för aktiviteter utanför hemmet, vilket är av betydelse för att förstå relationen mellan aktiviteter och platser. För att utveckla utformningen av rehabiliteringsinsatser som stärker möjlighet till aktivitet och delaktighet efter FHS behöver såväl aktiviteter som platser utanför hemmet samt aspekter som påverkar relationer dem emellan beaktas.
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| 47. |
- Olsson, Rickard, 1959-
(författare)
-
Analysis and Monitoring of Laser Welding and Surface Texturing
- 2019
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis can be conveniently divided into three sections as follows;Part I. Monitoring of laser welding In laser materials processing there has always been a need for suitable methods to supervise and monitor the processes on-line, to ensure correct production quality or to trigger alarms when failures are detected. Numerous investigations have been made in this field, including experimental and theoretical work. It is common practice in this field to monitor surface temperature, plasma radiation and back-reflected laser light, coaxially with the laser beam. Traditionally, the monitoring systems involved carry out no statistical analysis of the signals received – they merely involve thresholds.The first two papers in this thesis look at the feedback collected during laser welding using a co-axial setup from a Digital Signal Processing point of view and also uses high speed video photography to correlate signal perturbations with process anomalies. Digital signal processing techniques such as Kalman filtering, Principal Component Analysis and Cluster Analysis have been applied to on-line measurement data and have generated new ways to describe laser welding behaviour using parameters such as reflected pulse shape. The limitations of commercially available welding supervision systems have been studied and design suggestions for the next generation of on-line weld monitoring equipment have been formulated.Having progressed from thin section welding with continuous wave lasers to pulsed laser welding, the thesis then moves on to pulsed laser surface melting.Part II Analysis of surface texturing of titanium. The second part of the thesis concentrates on laser structuring of titanium surfaces for medical implants. The two papers in this section present an analysis of the laser-material interactions which create surfaces suitable for osseointegration (bone attachment). The work concentrates on a commercially available surface used for screw implants in dentistry; BioHelix™. This surface is generated by an intense bombardment of laser pulses and the surface is thus disrupted during solidification. The formation of various levels and types of roughness are analysed and it is noted that laser generated rough surfaces are fundamentally different from those with a mechanically produced roughness. One key point is that laser generated rough surfaces can include overhanging features. This finding lead to the research carried out in part III of the thesis.Part III. Analysis and classification of laser generated surfaces.The final section of the thesis presents research which uses statistical techniques to identify whether or not a roughened surface includes overhanging features. The presence or otherwise of such features is important because they can affect the wettability of surfaces and thus their suitability for implant surfaces, adhesive bonding and lubrication etc. Micro Computer Tomography was used to generate a typical cross section of the surface under investigation. At equally spaced positions the profile of this cross section is then allocated vectors which are normal to the profile at each point. The angles of the vectors can then be analyzed to reveal the presence or otherwise of overhanging features. The presence of overhangs on the material surface is indicated by the existence of normal vectors with angles that exceed 180°. The papers in this section also investigate possibilities and limitations of using statistical methods in conjunction with Micro Computer Tomography.The papers have in common processing of data for laser materials processing, by advanced methods to identify and extract essential information from the processes and the resulting material properties.
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| 48. |
- Riekkola, Jenni
(författare)
-
Older couples' participation in everyday life - when living in changing and shifting contexts
- 2019
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The overall aim of this thesis was to explore and develop an understanding about older couples’ participation in everyday life when living in shifting contexts. To achieve the aim, multiple perspectives were sought and a variety of qualitative methods were applied. Data were generated through interviews and observations with older couples and through focus groups with spousal caregivers, healthcare professionals, and other stakeholders and those data were analyzed through a constant comparative method, content analysis, and narrative analysis.From the perspective of spousal caregivers, the findings in study I revealed the complexity and ambiguity that influences participation in everyday life. Being in charge of everyday life was described as challenging in many ways and produced a need for recovery and own time. Interacting with social contexts and being confident with the provided social services, such as respite care, was described as complex. The partner’s wellbeing and participation had an impact on the spousal caregiver’s own participation when living in shifting contexts. The perspective of healthcare professionals related to residential respite care was captured in study II. They described a broad and multifaceted picture of participation in everyday life and how promoting participation for older couples involved building trustworthy relationships, enabling meaningful activities, and arranging a comfortable shared environment. Both of the partners in the older couples needed to be considered by the professionals. In study III, the perspectives of the older couples were explored. In order to understand how meaning and togetherness is created in older couples’ everyday life, the focus has to be on the couples’ whole situation, including their relationship. The results showed that the couples strived to continue living their lives in togetherness. Strategies used by the couples were shifting responsibilities, doing more things together than before, using residential respite care, and rearranging social interactions with family and friends. Study IV offered the perspectives of multiple stakeholders. The findings suggested that the focus has to be on older couples through maintaining abilities and creating comfort. Support is also required from both an engaged civil society and healthcare professionals that are motivated and have both competence and time. Further, social services need to work together to ensure that resources are properly available.Overall, this thesis contributes to a deeper understanding about older couples’ participation in everyday life when living in shifting contexts. The findings showed that acknowledging the couples’ relationship, seeing beyond the client and the spousal caregiver, was vital for supporting their participation. Furthermore, living in shifting contexts was multifaceted and the couples strived to continue living their lives in togetherness. The meaning that the change of life situation and context has on a couple’s participation in everyday life is important to consider when supporting aging in place. In light of demographic changes and challenges, bringing together the interests of older couples, professionals, systems of services, and civil society is vital for a sustainable future. Systems and situations that are both closely and remotely related to the older couples’ daily life need to be addressed in an ideal situation of aging in place. Knowledge from this thesis could be valuable for occupational therapists and other healthcare professionals, as well as social services that are supporting older couples to age in place. Consequently, this knowledge could be used to benefit the situations of older couples and their health and wellbeing when aging in place.
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| 49. |
- Ringblom, Lisa
(författare)
-
Utmanad ordning? En studie av kön och jämställdhetsarbete i den svenska gruvindustrins arbetsorganisationer
- 2019
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Män, maskulin symbolik och hårt manuellt arbete har länge präglat gruvan som arbetsplats. Samtidigt som detta fortfarande existerar, är idag allt fler gruvarbetare kvinnor, jämställdhetsarbete beskrivs som prioriterat samt att ny teknik och nya arbetssätt implementeras. Gruvans arbetsorganisationer uppvisar således en dubbelhet av stabilitet och förändring. Denna avhandling syftar till att undersöka hur kön och jämställdhetsarbete konstrueras och hur detta påverkar könsrelationer i den svenska gruvindustrins mansdominerade arbetsorganisationer. Med utgångspunkt i feministiska teorier förstås kön som ett görande och organisatoriska strukturer, processer och praktiker som konstituerande för sociala maktordningar i gruvans arbetsorganisationer. Avhandlingen bygger på fyra empiriska delstudier och baseras på ett femtontal arbetsplatsbesök samt tjugo intervjuer med gruvarbetare från arbetsplatser under jord och fyra intervjuer med personalchefer.Resultatet visar att relationen mellan kön och gruvarbete inte är given, utan ständigt förhandlas. Det ökande antalet kvinnor i gruvarbete försvårar upprätthållandet av arbetet som för och av män, och ny teknik och nya arbetssätt har öppnat upp för en omförhandling gällande vem och vilka som kan utföra gruvarbete. Tidigare var arbetet i gruvan reserverat för män, idag har den könsgränsen förflyttats inom gruvarbetet och mellan olika arbetsplatser och arbetsuppgifter. I den informella interaktionen mellan gruvarbetarna används jargongen för att bevara den rådande ordningen av mäns givna plats och dominans, men också som en arena för utmaning och motstånd. Arbetet för ökad jämställdhet motiveras framförallt av uppfattningen att jämställdhet stärker gruvföretagens lönsamhet och konkurrenskraft, något som i sin tur påverkar jämställdhetsarbetets innehåll. Jämställdhetsarbetet förväntas även bidra till en förbättrad psykosocial arbetsmiljö i och med att kvinnor anses ha någonting positivt och annorlunda (än män) att bidra med på arbetsplatserna. Kvinnor tenderar att förstås som en betydande del av problemet (bristen på kvinnor) och dess lösning (fler kvinnor) när dessa organisationer arbetar med jämställdhetsfrågor. I förlängningen innebär detta att det främst är kvinnor som befinner sig utanför organisationerna som ska lösa problemet med ojämställdhet i organisationerna. Organisationernas jämställdhetsgöranden har inte enbart bäring på könskonstruktioner och könsrelationer utan också andra maktrelationer i organisationerna, framförallt klass och plats. När gruppen män aktualiseras som ett problem i relation till ojämställdhet så är det inte alla män, utan arbetarklassmän i det rurala som beskrivs som problemet. På så sätt förstås (o)jämställdhet inte primärt som en fråga om makt, strukturer och processer inom den egna organisationen utan placeras främst på grupper av människor i (och utanför) organisationerna.
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| 50. |
- Saari, Esi
(författare)
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KPI framework for maintenance management through eMaintenance : Development, implementation, assessment, and optimization
- 2019
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Performance measurement is critical if any organization wants to thrive. The motivation for the thesis originated from the project “Key Performance Indicators (KPI) for control and management of maintenance process through eMaintenance (in Swedish: Nyckeltal för styrning och uppföljning av underhållsverksamhet m h a eUnderhåll)”, initiated and financed by a mining company in Sweden. The main purpose of this project is to propose an integrated KPI system for the mining company’s maintenance process through eMaintenance, including development, implementation, assessment, and optimization.There are gaps in the research, however, resulting in the following challenges. First, no KPI framework considers both technical and soft KPIs, so developing a system is problematic. Second, few studies have focused on implementing KPI measurement through eMaintenance. Third, there are gaps in KPI assessment. In assessing system availability, for example, the current analytical (e.g., Markov/semi-Markov) or simulation approaches (e.g., Monte Carlo simulation-based) cannot handle complicated state changes or are computationally expensive. In addition, few researchers have revealed the connections between technical and soft KPIs. For those soft KPIs for which the distribution of data collected from eMaintenance systems (e.g., work orders) is not easily determined, studies are insufficient. Fourth, the current continuous improvement process for the KPIs is very time-consuming. In short, there is a need for a new approach.The thesis develops an integrated KPI framework consisting of technical KPIs (linked to machines) and soft KPIs (linked to maintenance workflow) to control and monitor the entire maintenance process to achieve the overall goals of the organization. The proposed KPI framework makes use of four hierarchical levels and has 134 KPIs divided into technical and soft KPIs as follows: asset operation management has 23 technical KPIs, maintenance process management has 85 soft KPIs and maintenance resources management has 26 soft KPIs.The thesis discusses the proposed KPI framework; it lists the KPIs and provides timelines, definitions and general formulas for each specified KPI. Results will be used by the mining company to guide the implementation of the proposed KPIs in an eMaintenance environment.To suggest novel approaches to KPI assessment, the thesis takes system availability in the operational stage as an example. It proposes parametric Bayesian approaches to assess system availability. With these approaches, Mean Time to Failure (MTTF) and Mean Time to Repair (MTTR) can be treated as distributions instead of being “averaged” by point estimation. This better reflects reality. Markov Chain Monte Carlo (MCMC) approach is adopted to take advantage of both analytical and simulation methods. Because of MCMC’s high dimensional numerical integral calculation, the selection of prior information and descriptions of reliability/maintainability can be more flexible and realistic. The limitations of data sample size can also be compensated for. In the case studies, Time to Failure (TTF) and Time to Repair (TTR) are determined using a Bayesian Weibull model and a Bayesian lognormal model, respectively. The proposed approach can integrate analytical and simulation methods for system availability assessment and could be applied to other technical problems in asset management (e.g., other industries, other systems). By comparing the results with and without considering the threshold for censoring data, the research shows the connection between technical and soft KPIs, and suggests the threshold can be used as a monitoring line for continuous improvement in the mining company. For those soft KPIs for which the distribution of data collected from the eMaintenance system (e.g., work orders) is not easily determined, other approaches, such as time series analysis (if the data are “fast moving”), the Croston method (if the data are “intermittent”), or the bootstrap method (if the data are “slow moving”) could be applied. To ensure the KPI framework can be improved continuously, the thesis performs a comparison study to find the gaps between current and proposed KPIs in the mining company. It adapts a roadmap from the railway industry to show how optimization can be promoted by reviewing and improving the KPI framework.Results from this study will be applied to the company and guide its development, implementation and assessment of the KPIs through eMaintenance with continuous improvement. The proposed approaches could also be applied to other technical problems in asset management (e.g., other industries, other system).
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