| 51. |
- Brännström, Mattias
(författare)
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Integrated strength grading
- 2009
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This work comprises strength grading for structural timber according to European standards and prediction of grade-determining properties by various technologies and in various stages of the sawmilling process. The detection technologies applied on logs were outer shape scanning, laser scattering, x-ray scanning and resonance analysis. For boards, microwaves, laser scattering, x-ray scanning, resonance analysis and visual scanning applied. Tracing of log rotation angle has been done to enable reconstruction of boards based on the log-scanning results. Modelling of strength, modulus of elasticity and density has been done using partial least squares. A method for deriving settings for structural grades based on several modelled properties has been proposed: the smallest increment algorithm. Classification to structural grades has been made by this algorithm and by classification trees, all validated according to the method stipulated in the standard. Visual override was studied by grading strictly on deformation criteria. Profitability of a grading process has been studied, based on relative net mill prices and production costs for structural timber and alternate grades from 2007. The quality of the grades has been briefly studied by analysis of the lower tail of some strength distributions. The result shows that all grade-determining properties must be estimated to achieve high raw material utilization and quality. The means for such estimation is not important, but the quality of the variables derived, based on the technology, is critical to the result. It was shown that tracheid-effect scanning by laser scattering gave variables valuable for strength prediction and that microwave signals in a very basic form provided more information than density alone. Log scanning by x-ray and resonance analysis enabled machine strength grading to the strength grade C40 already at the timber yard. It was indicated that the log-graded material below the 5th percentile was weaker than the board-graded material of the same grade. The result from pregrading by log grading showed itself in improved profitability for certain grade combinations and market conditions. As expected, the financial result is strongly dependent on the structural timber and alternate grade properties and price, grading accuracy and properties of the species. Different equipment can classify a specimen differently, although the final properties of the final grade fulfil the requirements for both machines. For this reason, it is important to select the stronger material in pregrading. Doing the opposite will alter the distribution to the unsafe side. The conclusion is that an integrated strength-grading process gives flexibility and enables the producer to meet well-defined customer specifications for structural wood products.
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| 52. |
- Brännström, Robert
(författare)
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Mobility management in heterogeneous access networks
- 2007
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis proposes, describes and validates solutions to enhance mobility in heterogeneous access networks. Wireless access networks have become available almost everywhere and current research strives to make them pervasive. Users having wireless access to the Internet are driving the demand for mobile and heterogeneous solutions where services could be accessed from anywhere, any time and from any device. Future wireless connectivity will be provided through a mix of coexisting heterogeneous access network technologies. To enhance mobility in heterogeneous networks this thesis focuses on mobility management systems and connectivity of wireless multi-hop ad hoc networks to the Internet. In a wireless environment with overlapping service areas, mobile nodes need to select which gateway(s) to use to access the wireless infrastructure. The metrics used to select the point of attachment within an access technology are insufficient to compare the capacity of different technologies or multi-hop routes. This thesis proposes, describes and validates solutions to calculating network layer metrics and using them in gateway selection and handover decisions. To enable connectivity of a mobile ad hoc network (MANET) to the Internet, a gateway must bridge the wired single-hop and wireless multi-hop approaches. A MANET enables connectivity to more than one gateway at a time and combined with multihoming it provides seamless handover between subnets. The gateway selection and handover decisions are complicated by the multihoming capabilities. Connectivity to Internet services makes it important to maintain the efficient route to the gateway. It is also important to identify the location of a destination to separate the management of Internet and intra MANET destinations. This thesis proposes,describes and validates solutions to deploying multihomed mobility into MANETs and thereby handling multi-hop gateway discovery, registration of multiple gateways and tunneling to selected gateway(s). The solution maintains gateway connectivity in MANETs by installing routes to gateways using advertisements and manages route discovery based on the destination locality. Both applications with mobility awareness (e.g. SIP phones) and those without it must be supported by a mobility management system. The existence of network layer mobility management can enhance an application layer system. This thesis proposes, describes and validates deployment of a mobility management system with support of both application and network layer mobility. With wireless access networks some technologies might not support some types of applications and a single technology might not cope with all the application demands from a mobile node. Thus the control of individual traffic flows could be used to share the load on multiple access technologies and to direct flows over specified technologies. This thesis proposes, describes and validates solutions to identification and mobility management of individual traffic flows in a heterogeneous network environment. Finally this thesis proposes, describes and validates a deployment proposal of route evaluation and flow control to enable load balancing in wireless multi-hop networks.
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| 53. |
- Bui, Thong
(författare)
-
Antecendents of intention to use mobile music services : a study among Swedish consumers
- 2007
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This study investigates the antecedents of intentions to use mobile music services among Swedish consumers. Relying on the theory of planned behavior, image congruence theory, and the technology readiness index, the study proposes an integrated research model that explains consumer intentions to use mobile music services. In the model, attitude, subjective norm, perceived behavioral control, image congruence and technology readiness index are independent variables and behavioral intention is the dependent variable. Seven hypotheses are suggested. Hypotheses 1 to 4 are about the positive relationships among attitude, subjective norm, perceived behavioral control, image congruence, and behavioral intention. Hypothesis 5A postulates a positive relationship between technology readiness index and intention. Hypothesis 5B suggests a positive relationship between the technology readiness index and perceived behavioral control. Hypothesis 5C considers the possibility that the effect of the technology readiness index on intention is mediated by perceived behavioral control. A cross-sectional survey is conducted among 334 respondents from a shopping center sample. Bivariate correlations and multiple regressions were used to test the hypotheses. Attitude is found to be the strongest predictor of intention, followed by image congruence, subjective norm, and perceived behavioral control. The technology readiness index correlates with perceived behavioral control but not with intention. Thus hypotheses 1 to 4 as well as hypothesis 5B are supported, hypothesis 5A is not supported and hypothesis 5C is not found to be applicable. A second survey with a convenience sample of students at Luleå University of Technology validates the results from the first survey. Since image congruence contributes significantly and independently to the explanation of intentions to use mobile music services, the proposed research model improves the prediction of consumers' intention over the TPB. This implies that, for a service like mobile music, practitioners should consider symbolic and expressive motives in addition to utilitarian benefits.
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| 54. |
- Bäckström, Lars
(författare)
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Personal selling and relationships : a review and explorative essay
- 2008
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The overall scope of this doctoral thesis is focusing on selling. The thesis contains two studies; Study A is a synopsis of a licentiate thesis published in 2002, while Study B contains three journal articles. Study A examined industrial selling in Swedish manufacturing small and medium-sized enterprises (SMEs). The research addressed three research questions dealing with selling activities, individuals involved in selling, and selling processes in three different selling contexts. Study A adopted a qualitative research approach; it used a case study research strategy and collected the primary data through personal interviews. The study included four cases, interviewing a total of 19 respondents in various positions within the selected companies. The study's findings indicate that selling activities performed by manufacturing SMEs in this study are complex and include a variety of activities. The numerous individuals found to be involved in selling represented several different functions within the selling company. Furthermore, the findings indicated that the studied companies included external individuals when performing their selling activities. Finally, the performed selling activities could be described in several selling processes. These findings suggest that the selling processes vary from rather simple and transaction-oriented selling processes to more complex processes dealing with both long-term customer relationships and single transactions. Study B examined relationships in selling in the financial services industry, looking specifically at the relationships between members of a sales force and other members of the same organization as well as relationships between salespeople and customers. All three articles included in this study applied a quantitative research approach. The first article, "The Impact of Incentives on Interfunctional Relationship Quality: Views from a South African Firm," sought to discover the extent to which different functional groupings perceived the incentives an organization offers its personnel as being "fair." The setting for the research in this article was a small- to medium-sized marketer of financial services in a South African context. Data were collected using questionnaires; 141 usable responses were received, representing a response rate of 81 percent. The findings from this article provide evidence that small but significant differences exist in the perceptions of the fairness of incentives provided. The second article, "Trusting Relationships. How Salespeople View the Quality of Relationships with Friends and Customers," as well as the third article "Personal Acquaintances and Salespeople in Financial Services: Differences Between Customers and Friends," deals with the relationships between salespeople and friends, salespeople and good customers, and salespeople and bad customers. However, the two articles used different scales to measure these relationships. In the second article, relationships were measured using the Trusting Relationship questionnaire; in the third article, relationships were measured using the Personal Acquaintance measure. Data from both articles were gathered from a large Swedish firm in the financial services industry through questionnaires sent to salespeople. The questionnaire resulted in 119 usable responses for both articles, corresponding to a response rate of 60.1 percent. Based on the results presented in both articles, salespeople do not perceive relationships with friends in the same way as they perceive their relationships with customers. Similarly, both articles provide evidence that salespeople perceive relationships with good customers to be different from those with bad customers.
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| 55. |
- Candell, Olov
(författare)
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Development of information support solutions for complex technical systems using eMaintenance
- 2009
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Deployment and use of complex technical systems are common in society and in industry. Many of the complex technical systems have stringent requirements on safety, dependability and cost, which necessitate frequent updates and modification in response to new developments in technology and changing functional requirements. Hence, correct, role-adapted, situation-adapted, context-adapted and timely information and information support, is crucial to access, manage, maintain and improve the required services to be provided by these systems. Given the technological development and the changing business environment, system and support providers need to improve the design and provision of information support solutions. This can be facilitated by the utilisation of new and innovative Information & Communication Technology (ICT), manifested in emerging approaches such as eMaintenance. However, there is still a need of methodologies and tools that enable the development and provision of support information services by an integration of business and maintenance processes at both customers and providers to achieve novel business solutions such as Performance-Based Logistics (PBL) in the context described above.Hence, the purpose of this research is to describe how providers of support solutions can develop and provide effective information support solutions related to complex technical systems by enhanced utilisation of ICT. To fulfil this purpose, a single case study within military aviation was performed. Empirical data was collected through interviews, observations, archival records, workshops and action research. The analysis was based on existing, adapted and developed theories, model-based simulations and available international standards, considering an eMaintenance framework.The results of the research are: I) a definition of system-oriented, service-oriented, process-oriented and lifecycle oriented eMaintenance solutions; II) an identification of critical information and information support requirements of customers and providers while implementing e-maintenance; III) an identification of ICT-related methodologies and technologies suitable to fulfil the information support requirements of customers and providers; and IV) an approach for development and provision of ICT-based information support solutions that satisfy the requirements of customers and providers. Even though these results are achieved within the context of a modern military aircraft, the results throughout the research process indicate that they to a large extent are generic in nature and can be applicable to other complex technical systems within the process, power generation and transportation industries as well.
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| 56. |
- Carlsson, Ella
(författare)
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Mars : plasma environment and surface hydrology
- 2008
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This doctoral thesis treats parts of the solar wind interaction with the Martian atmosphere and the water-related features known as gullies. The composition of the escaping plasma at Mars has been investigated in an analysis of data from the IMA sensor, which is a part of the ASPERA-3 instrument suit onboard the European satellite Mars Express. The goal of the investigation is to determine if there are any high abundances of escaping ion species incorporating carbon, such as in CO_2^+ . The most abundant ion species was found to be O^+ and O_2^+, followed by CO_2^+. The following ratios were identifed: CO_2^+/O^+ = 0:2 and O_2^+ /O^+ = 0:9. The escaping plasma, in form of ion beam events, has also been correlated to the magnetic anomalies found on the surface, where no clear association was found. Similar ion beams have also been detected on Venus, which does not have any crustal magnetic fields, and hence the fields are not required for the formation process of the beams. The ion beams' dependence of the direction of the solar wind convection electric field has also been studied, where a correlation was found, suggesting that the ion beams are accelerated by this field. The studies mentioned above are important in order to understand the evolution of Mars and its atmosphere, as well as plasma acceleration processes at non-magnetized planetary bodies. On 5 December 2006 the ASPERA instruments of both Venus Express and Mars Express detected a large enhancement in their respective background count level. These readings are associated with events of SEPs (Solar Energetic Particles), which are believed to be coupled with the CMEs (Coronal Mass Ejection) identified 43 ¡ 67 hours after the SEPs. The CMEs occurred on the far side of the sun (with respect to the locations of Venus and Mars), which indicates that these events can a®ect the space weather in areas situated 90 degrees in both azimuthal directions in the heliosphere with respect to the target. During this event the heavy ion outflow from the atmosphere of Mars increased by one order of magnitude, suggesting that EUV flux levels significantly affect the atmospheric loss from unmagnetized bodies. The gully formations have been investigated with data from the MOC, MOLA and TES instruments onboard the satellite Mars Global Surveyor. The features suggest that there has been fluvial erosion on the surface of Mars. The shallow and deep aquifer models remain the most plausible formation theories. Gully formation processes are important to understand since their eroding agent may be liquid water.
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| 57. |
- Carlswärd, Jonas
(författare)
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Shrinkage cracking of steel fibre reinforced self compacting concrete overlays: test methods and theoretical modelling : test methods and theoretical modelling
- 2006
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Steel fibres are often applied as crack reinforcement in overlays even though methods for the design with respect to crack widths are not yet available. Thus, the intention was for the research to form a basis for future design of overlays with respect to cracks. A main ambition was to give guidance on e.g. type of steel fibre reinforced concrete (SFRC) required to limit crack widths and how to prepare the substrate surface in order to produce a high and even base restraint. Test methods and theoretical analysis has been applied to fulfil the aims. The experimental part consisted of end-restrained shrinkage tests, bond tests and half scale overlay tests. End-restrained shrinkage and half scale overlay tests were conducted in order to evaluate the effect of steel fibres for different restraint situations while the bond tests were intended to give information regarding the appropriateness of different substrate treatments from a bond strength perspective. Test results showed that the situation of restraint has a significant influence on the cracking response. A single crack developed if the overlay was restrained only at the ends for both un-reinforced concrete as well as for SFRC. However, the crack width was found to be reduced due to the addition of steel fibres. In case of a continuous restraint provided by bond to the substrate on the other hand, numerous well distributed, fine cracks were observed. For this situation there was no measurable influence of fibres on the width and distribution of cracks. A conclusion is thus that reinforcement is not required in case of thin overlays (depths of 50 mm have been studied) if a high and even bond strength is obtained. Test results verified that high bond strength can be achieved by pre-moistening the substrate prior to overlaying, in combination with thorough cleaning. However, the substrate should be allowed to dry back prior to overlaying, as a wet surface was shown to be deteriorating for the bond strength. Caution is also recommended if the overlay is cast onto a dry substrate. In case of insufficient bond strength, with an apparent risk for partial debonding, i.e. parts of the overlay debond while other parts are still bonded, reinforcement is however required to limit crack widths. A theoretical method has been proposed for the design of SFRC for such situations and predictions have been verified through comparisons with experimental results.
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| 58. |
- Cervantes, Sara
(författare)
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Attitudes towards starting small business : youth and local authorities in a changing labour market?
- 2005
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The aim of this thesis is to examine the extent to which a local authority can change the attitudes of its youth, away from public sector employment to the development of small business, through education. Traditionally the region of Norrbotten has favoured the public sector. Yet the dominance of this sector has recently been challenged by ideas that promote the private sector and small business, and advocate the rise of entrepreneurship. Attempts to operationalise the shift from public to private sectors can be seen in the development of entrepreneurship education in upper secondary school, where the main consideration is that young people should become aware of alternative options for future work, the main objective being to influence young people’s attitudes to enterprise with a view to fostering the growth of entrepreneurial tradition. The methods used for the research reported in the thesis are triangulation. Interviews were conducted with students, teachers, people in leading positions and project leaders; statistics and documents were collected; and questionnaires were answered by pupils involved in entrepreneurship education in one local authority, as well as pupils in two other local authorities in the region of Norrbotten. The data collection was thus undertaken in three local authorities in the northern part of Sweden. Two central concepts used in this thesis are ‘attitudes’ and ‘youth’. Attitudes are defined, following Angelöw and Jonsson (1990), as thoughts and knowledge that deal with ideas and notions, alongside an emotional component that accounts for the feelings about an object and actions that occur in specific situations. Youth is defined as a process in which young people develop in order to become adult; this is influenced by gender, social background and ethnicity. The theoretical framework examines youth, individualization, mobility, risk and agency in a changing society. The concept of neo-liberalism is also considered as a political background in order to help enrich our understanding of these changes in context. The conclusions of the research investigation indicate that local authorities want to develop their local labour markets in order to entice young people stay or move back to the local area. The focus on entrepreneurship shows the development of a pervasive neo-liberalism and individualization in society. In this context it is shown how local authorities take relatively small risks, at least compared to young people who take much greater risks in seeking to start their own business. Young people are aware that they are being encouraged to become entrepreneurs, but they are also acutely aware of the risks associated with starting a business. Entrepreneurship education provides the young people involved with an understanding of both the potential rewards and perils of business ownership, leaving them in little doubt of the risks involved. Risk thus becomes visible for these young people, who are provided with the skills and knowledge to calculate their likely success, or failure. An important insight from the research investigation on which this thesis is based is that the local authorities concerned do not involve young people when making their plans for the future. Instead, they act as if they and their young people inhabit separate worlds. Yet, when politicians speak, they do so from above, assuming that their plans and visions are rooted in the reality facing young people in contemporary society. Even so, it is shown that the majority of young people between 18 and 24 years of age leave their hometowns in order to achieve experience of other places. The main consideration for them is to seek education and meet new people, see new places and gain experience of new cultures. Despite the best efforts of local authorities’ leaders, it would appear that the majority of young people simply cannot place themselves as small business owners until they have achieved experience of life elsewhere.
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| 59. |
- Chaikumarn, Montakarn
(författare)
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Ergonomic evaluation of technology change at work and its effect on health
- 2005
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The change at work in the context of technology change has affected human’s health in relation to their working condition, attitude, and MSDs risk factors. These changes were included: adopting new tools, work concept work environments, and work system. Ergonomic methods, can be applied as tools for identify, evaluate these effects of the changes whether they give better health and work condition to workers. The purpose of this thesis is to apply the ergonomic methods to evaluate/identify the work conditions, MSD risk factors where the change at work existed for preventing MSDs in the context of technology change. This thesis compiled with 5 studies as followed: Study I, the Proprioceptive derivation (Pd) concept has introduced to Thai dentistry, and the aim of this study was to assess the working conditions and the attitude among experienced users. Questionnaires were distributed among 12 dentists. The results showed that the Pd concept seems to reduce the stress level of dentists, but the continuous sitting posture adopted is a risk for back pain in dentists, from the ergonomic point of view. The Pd concept with a dental bed can provide easy accessibility to patients with physical limitations and it results in a lower stress level among dentists. Most dentists who used Pd found it useful. Study II, the aim of this study was to investigate the differences in dentist’s working posture when adopting different work concepts: - Pd and Conventional concept. The observation methods and RULA assessment were applied. The result showed differences in dentists’ sitting posture, clock- related working position, and RULA score. It implied that Pd concept helps the dentists to discover new ways to position themselves, and working comfortably and effectively, which made it possible for the dentists to adopt better working posture and have lower RULA score. Study III, a redesigned cleaning tool was introduced to the cleaners. The physiological, trunk posture and subjective assessment were measured. The results found that floor cleaning in the train wagons is associated with moderately high cardiovascular load and high frequency of stressful working postures. An introduction of the redesigned cleaning tool allowed cleaners to maintain more upright posture while cleaning, which reduce biomechanical and physiological loads on them. Study IV, applied participatory ergonomic method for identification of the cleaning problems and to evaluate the effect of the low-cost improvement on the cleanersด working posture by using OWAS method. Results showed through participatory ergonomics method cleaning problem was identified, and ergonomic solution suggested by cleaners were implemented as low-cost improvement. A low-cost improvement has improved the working posture of cleaners by eliminating the awkward working postures such as sitting on one and two bent knees, and arm above the shoulder. Study V, ergonomic and production system effectiveness are evaluated in a case of a production system redesign: from parallel flow dock-based, to serial flow line-based assembly. The line-based system displayed much tighter coupling of operators to the technical system and introduced system, balance and downtime losses. We observed reductions in: cycle times to 6% of previous, decision latitude, influence and control over work, perceived work load, and perception of available pauses. Layout and technology changes helped improve co-worker interaction and support, and reduce instances, but not magnitude, of peak spinal loading. It is concluded that serial flows can negatively affect psychosocial conditions and, if losses are high, reduce physical workload. An ‘Action Group’ has been formed in the company to adopt an evidence-based approach to the development of systems that are sustainable from both productivity and ergonomics perspectives. In conclusion, technology changes can give both positive and negative effects on the humans’ health. Ergonomic methods can be used to evaluate these effects. Self-reported questionnaire can give the information on working condition, and attitude of the people working under the change in technology. RULA and OWAS were very useful for identifying and analyzing the postural risk factor. Direct measurement such as physiological responses was useful to identified work load on human body. Participatory ergonomic is also a very useful method for identifying problem, and possible solutions for improving the working conditions. Further, the results from ergonomic evaluation can provide useful information which is needed for future intervention or work-system design in each industry for preventing MSDs at the work place.
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| 60. |
- Chronéer, Diana
(författare)
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Product development in process industry : changes and consequences
- 2005
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis addresses the issue of product development in Process Industry, and it is presented in the form of six appended papers together with an extended summary. Product development in Process Industry is not widely researched upon, and even less in the Swedish process Industry. For these reasons, the focus of this thesis is specifically on product development in Swedish Process Industry and on some of the consequences of a changed perspective in product development work in Process Industry. The selected research strategy has been a combination of exploratory interviews and a survey. The main academic contribution of the research is the elaboration of some of the implications of a changed perspective in development work for Swedish process industries. One contribution is that an analysis of the entire supply chain for a process-based company and its actors can facilitate this change towards a more product-focused development. Further, this thesis shows that the two disciplines; Management of Technology and Supply Chain Management can together emphasise some of the aspects that must be highlighted in order to understand and create effective product development in Process Industry. The main managerial implication of the research is the investigation of a changed perspective for Swedish process-based companies and the implications of such a change. Development managers can facilitate the change towards a more product-oriented focus in development projects by thoroughly view and analyse product development work as a process in the supply chain. Sources of innovation and key actors can be both suppliers (of machine equipment or raw material) and customers (customers and/or end- customers). However, an analysis of vital sources of innovation can require changes in both organization and means to cooperate).
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