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| 2. |
- Bourdieu, Pierre, et al.
(författare)
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Leve idrottspedagogiken : En vänbok tillägnad Lars-Magnus Engström
- 2005
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Bok (övrigt vetenskapligt/konstnärligt)abstract
- Vem ägnar sig åt idrott? Vilken betydelse har fritiden i barns och ungdomars liv? Vad innebär hälsa i skolämnet idrott och hälsa?Leve idrottspedagogiken! tillägnas Lars-Magnus Engström. Texterna i boken speglar delar av det idrottspedagogiska forskningsområdet i Sverige, vars framväxt Lars-Magnus Engström varit den främste företrädaren för. Läsaren får här ta del av exempelvis idrottskulturen, fritidskulturen och skolans ämne idrott och hälsa. Genomgående handlar texterna om villkoren för barns och ungdomars deltagane och om de olika lärprocesser som sker i anslutning till idrottsutövning.Lars-Magnus Engström har gjort betydande insatser som forskare och lärare samt som professor vid Lärarhögskolan i Stockholm och vid Gymnastik- och idrottshögskolan. I snart fyrtion år har han arbetat med studier kring påverkans- och lärprocesser i idrott. Hans forskning har främst kretsat kring människors idrottsvanor och vilka som utvecklar en fysiskt aktiv livsstil. Idrotts- och motionsutövningar ger både ett så kallat egenvärde och investeringsvärde. Med dessa begrepp bland många andra har Lars-Magnus Engström bidragit till en fördjupad vetenskaplig förståelse av idrottskulturen.De flesta författarna har eller har haft Lars-Magnus Engström som handledare och tillhör forskningsgruppen för pedagogik, idrott och fritidskultur. Redaktörer för boken är Karin Redelius och Håkan Larsson.
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| 3. |
- Larsson, Bengt, 1953-
(författare)
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Ungdomarna och idrotten : tonåringars idrottande i fyra skilda miljöer
- 2008
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The main aim of the study is to generate increased knowledge about young people’s leisure time sporting habits in a contextual perspective. The intention is to highlight the circumstances in which young people pursue and participate in different activities, with a particular focus on sport in terms of one’s own life circumstances. An essential point of departure of the study is regarding sport as an important pedagogic environment of norms and values.The perspective of the study is mainly cultural-sociological. In the analyses, Pierre Bourdieu’s key concepts habitus and capital have been used as research tools together with gender. The data on which the thesis is based is collected from young people from school year 9 living in four different milieus and comes from three different collections, conducted in 1996, 2002 and 2007. In each data collection about 1200-1500 pupils replied to a questionnaire.Sport occupies a central position in young people’s life on the recreational field. The results show that sport culture can best be understood in the local perspective. Young people’s sporting habit development can be said to be a result of a complex interplay between personal preferences, the home environment, local traditions, what is on offer, living conditions and the prevailing laws of gender and status.For the group of teenagers as a whole the proportion of members, as well as those who pursue personal sports, increases with higher educational capital and higher economic capital. When it comes to organised sport outside the sports club milieu no such connection can be determined.The thesis has shown that sport is not accessible for all and opportunities for participation are curtailed for large groups of young people in our society. This is especially true for sport organised in sport clubs, i.e. sport mainly supported by public funds.
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| 4. |
- Thörnblad, Karin, 1971, et al.
(författare)
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A competitive iterative procedure using a time-indexed model for solving flexible job shop scheduling problems
- 2013
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- We investigate the efficiency of a discretization procedure utilizing a time-indexed mathematical optimization model for finding accurate solutions to flexible job shop scheduling problems considering objectives comprising the makespan and the tardiness of jobs, respectively. The time-indexed model is used to find solutions to these problems by iteratively employing time steps of decreasing length. The solutions and computation times are compared with results from a known benchmark formulation and an alternative, slightly enhanced version of the same. For the largest instances---considering both objectives---the proposed method finds significantly better solutions than the other models within the same time frame, although there is a large difference in the performance of the models depending on which objective is considered. This implies that the evaluation of scheduling algorithms must be performed with respect to an objective that is suitable for the real application for which they are intended. The minimization of the makespan is no such objective, although it is the most widely used objective in research. We propose an objective incorporating tardiness. The iterative procedure for solving the time-indexed model outperforms the other models regarding the time to find the best feasible solution. We conclude that our iterative procedure with the time-indexed model is competitive with state-of-the-art mathematical optimization models. Since the proposed procedure quickly finds solutions of good quality to large instances, our findings imply that the new procedure is beneficially utilized for scheduling real flexible job shops.
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| 5. |
- Thörnblad, Karin, 1971, et al.
(författare)
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A note on the complexity of flow-shop scheduling with deteriorating jobs
- 2011
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Ingår i: Discrete Applied Mathematics. - : Elsevier BV. - 0166-218X. ; 159:4, s. 251-253
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Tidskriftsartikel (refereegranskat)abstract
- This paper is a note on “Complexity analysis of job-shop scheduling with deteriorating jobs” [G. Mosheiov, Complexity analysis of job-shop scheduling with deteriorating jobs, Discrete Applied Mathematics 117 (2002) 195–209]. A proportional deterioration rate is assumed and the objective is the minimization of the makespan. Mosheiov presents NP-hardness results for flow-shops and open-shops with three or more machines and for job-shops with two or more machines. The proof of NP-hardness for the flow-shop case is however not correct. This paper provides a correct proof.
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| 6. |
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| 7. |
- Thörnblad, Karin, 1971, et al.
(författare)
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An efficient algorithm for solving the flexible job shop scheduling problem
- 2013
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Ingår i: 25th NOFOMA conference proceedings, June 3-5 2013, Göteborg, Sweden.
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Konferensbidrag (refereegranskat)abstract
- Purpose: To investigate the efficiency of a discretization procedure utilizing a time-indexed mathe-matical optimization model for finding accurate solutions to flexible job shop scheduling problems considering objectives comprising makespan and tardiness, respectively. Design/methodology/approach: A time-indexed mixed integer programming model is used to find solutions by iteratively employing time steps of decreasing length. The solutions and computation times are compared with results from a known benchmark formulation and an alternative model. Findings: The proposed method finds significantly better solutions for the largest instances within the same time frame. Both the other models are better choices for some smaller instances, which is expected since the new method is designed for larger problems. Only our alter-native model is able to solve two of the largest instances when minimizing the tardiness. Research limitations/implications: Interesting future research topics include the introduction of constraints representing other relevant entities such as the availability of tools and fixtures, and the scheduling of maintenance activities and personnel. Practical implications: Real cases of flexible job shop problems typically yield very large models. Since the new procedure quickly finds solutions of good quality to such instances, our findings imply that the new procedure is beneficially utilized for scheduling real flexible job shops. Original/value: We show that real flexible job shop problems can be solved through the solution of a series of carefully formulated discretized mathematical optimization models.
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| 8. |
- Thörnblad, Karin, 1971, et al.
(författare)
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Mathematical modelling of a real flexible job shop in aero engine component manufacturing
- 2011
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Ingår i: Proceedings of 10th Workshop on Models and Algorithms for Planning and Scheduling Problems, June 2011, Nymburk, Czech Republic.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- We formulate two mixed integer programming models stemming from a real flexible job shop problem with a total of ten resources and five main processing multipurpose machines. The models are compared w.r.t. memory usage, computation times, and accuracy.
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| 9. |
- Thörnblad, Karin, 1971, et al.
(författare)
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Mathematical optimization of a flexible job shop problem including preventive maintenance and availability of fixtures
- 2012
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Ingår i: Proceedings of the 4th World P&OM Conference / 19th International Annual EurOMA Conference, Amsterdam, Netherlands, July 2012.
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Konferensbidrag (refereegranskat)abstract
- The multitask cell at Volvo Aero Corporation is a flexible job shop containing ten resources aimed at being flexible with regard to product mix and processing types. Computing schedules for this type of job shop is an NP-hard problem. The computation times will therefore always be an issue, especially as the scheduling problem includes limited availability of fixtures and preventive maintenance planning. Computational results show that with the method developed we are able to produce optimal, or near-optimal, schedules for real data instances within an acceptable time frame. The scheduling principle proposed shortens lead times and minimizes tardiness.
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| 10. |
- Thörnblad, Karin, 1971, et al.
(författare)
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Optimering av scheman för en verklig produktionscell: tidsdiskretisering reducerar lösningstiden utan att lösningarnas kvalitet försämras
- 2011
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Ingår i: PLANs forsknings- och tillämpningskonferens, 31 aug-1 sep 2011, Norrköping, Sverige.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Vid optimering av industriella schemaläggningsproblem är kompromissen mellan beräkningstid och resultatnivå ofta kritisk, med risken att en optimeringsmodell förenklas så mycket att dess resultat inte är praktiskt relevant. I artikeln jämförs två matematiska optimeringsmodeller för optimal schemaläggning av en verklig produktionscell på Volvo Aero. I den ena modellen beskrivs bl. a. operationers starttider m.h.a. kontinuerliga variabler, medan tiden har diskretiserats i den andra modellen. Diskretiseringen innebär att planeringshorisonten indelas i ett antal tidssteg, här kallade diskreta tidsperioder. Det är en förenkling eftersom all indata då måste uttryckas i helt antal diskreta tidsperioder och varje operation endast kan schemaläggas vid början av en tidsperiod. Den senare modellen visade sig överlägsen vad gäller beräkningstider och bedömdes därför ha mycket stor potential, trots risken för approximeringsfel p.g.a. tidsdiskretiseringen. 2 I artikeln presenteras tester med verkliga indata, vilka visar att approximeringsfelen blir mycket små när den diskreta tidsperiodens längd är en timma eller mindre, trots att några operationstider är kortare än så. Det optimala schemat från den tidsdiskreta modellen har före jämförelsen justerats så att alla operationstider är de ursprungliga, detta utan att förändra vare sig maskinval eller valda sekvenser på maskinerna. Denna modell har goda förutsättningar att fungera praktiskt, eftersom den både är snabb och ger goda resultat.
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| 11. |
- Thörnblad, Karin, 1971, et al.
(författare)
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Optimization of schedules for a multitask production cell
- 2010
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Ingår i: Proceedings of The 22nd NOFOMA Conference in Kolding, Denmark, 10-11th of June 2010.
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Konferensbidrag (refereegranskat)abstract
- Purpose of this paper; To optimize production schedules of a real production cell containing multi-purpose machines working as a job-shop in a complex logistic environment producing aircraft engine components. The planning and control of the production in the so called multitask cell results in a complex combinatorial problem. Design/methodology/approach; A mathematical optimization model of the multitask cell has been developed and tested on real data instances. The current production planning prerequisites have been studied in order to choose an appropriate objective function. Findings; Production plans resulting from the optimization model, are compared with schedules formed by the First in First Out (FIFO) and Earliest Due Date (EDD) priority rules, which are similar to the current manual planning of the multitask cell. Practical implications; The proposed scheduling principle will shorten lead times, and provide a more efficient use of the resources of the multitask cell. The effects are most significant at times with high utilization of the cell. What is original/value of paper; The development of theory and practice of optimization, together with the development of computer hardware during the past decades, enable the utilization of optimization as a tool for computing efficient production schedules in a complex logistic environment.
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| 12. |
- Thörnblad, Karin, 1971, et al.
(författare)
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Scheduling optimization of a real flexible job shop including fixture availability and preventive maintenance
- 2015
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Ingår i: European Journal of Industrial Engineering. - 1751-5254. ; 9:1, s. 126-145
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Tidskriftsartikel (refereegranskat)abstract
- The multitask cell at GKN Aerospace Sweden is a flexible job shop containing ten resources aimed at being flexible with regard to product mix and processing types. We present a time-indexed formulation of the problem of optimally scheduling the planned jobs on the resources, also considering a limited availability of fixtures as well as required preventive maintenance activities. The objective is to minimize a weighted sum of the completion times and tardiness for the jobs, where the tardiness weight for a given job is a non-increasing function of its due date. We propose a fast iterative approach to finding a suitable value of the length of the time horizon that needs to be set for the time-indexed formulation and which considerably influences the computation time. Computational results show that the method developed is able to produce optimal, or near-optimal, schedules for real data instances within an acceptable practical time frame.
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| 13. |
- Thörnblad, Karin, 1971, et al.
(författare)
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Scheduling optimization of a real flexible job shop including side constraints regarding maintenance, fixtures, and night shifts
- 2013
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- We present a generic iterative scheduling procedure for the scheduling of a real flexible job shop, the so-called multitask cell at GKN Aerospace Engine Systems in Sweden. A time-indexed formulation of the problem is presented including side constraints regarding preventive maintenance, fixture availability, and unmanned night shifts. This paper continues the work in [35], with an improvement of the iterative solution procedure and the inclusion of constraints regarding night shifts during which only unmanned processing is allowed. The resulting schedules are compared with schedules constructed using two priority dispatching rules. Computational results show that the gain of including the night shifts constraints is significant and that the methodology developed is able to produce near-optimal schedules for industrial data instances for the coming shift within an acceptable practical time frame.
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| 14. |
- Thörnblad, Karin, 1971, et al.
(författare)
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Scheduling optimization of a real flexible job shop including side constraints regarding maintenance, fixtures, and night shifts
- 2015
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Ingår i: Proceedings of the 7th Multidisciplinary International Conference on Scheduling: Theory and Applications (MISTA 2015). 25 -28 Aug 2015, Prague, Czech Republic. - 2305-249X. ; , s. 78-101
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Konferensbidrag (refereegranskat)abstract
- We present a generic iterative procedure for the scheduling of a real flexible job shop, the so-called multitask cell at GKN Aerospace Engine Systems in Sweden. A time-indexed formulation of the scheduling problem is presented—including side constraints regarding preventive maintenance, fixture availability, and unmanned night shifts. This paper continues the work in ”Scheduling optimization of a real flexible job shop including fixture availability and preventive maintenance” [Thörnblad et al., European Journal of Industrial Engineering, 2015], with an improvement of the iterative solution procedure, and the inclusion of constraints regarding night shifts during which only unmanned processing is allowed to be scheduled. Schedules resulting from our procedure and from the use of two priority dispatching rules are compared. The gain of including the night shifts constraints is significant. Despite the added complexity, our methodology produces near-optimal schedules for industrial data instances for the coming shift within an acceptable practical time frame.
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| 15. |
- Tidén, Anna
(författare)
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Bedömningar av ungas rörelseförmåga : En idrottsvetenskaplig problematisering och validering
- 2016
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The overall purpose of this thesis is to investigate, discuss and problematise different aspects of movement ability. The four sub-studies of the thesis deal with various issues concerning assessment of movement ability. First, the focus is on how the concept of physical literacy has influenced the steering document of the subject physical education and health (PEH) in Sweden. The question is: What kind of tensions and conflicts arise when different approaches and interpretations of movement ability are used in an educational context? Second, a structural validation is conducted of the NyTid test, an assessment tool developed to assess basic and complex movement skills at the ages of 12-16 years. The question is: Which categories of movement skills are identified through the validation of the NyTid test? Third, the study examines how ‘ability’ is conceptualised, configured and produced in movement tests and movement assessment tools. Finally, an investigation of how or whether an assessed low or high movement ability at the age of 15 matters for developing an interest in, or taste for, sport and physical activities nine years later, in young adulthood.Movement ability is studied from different perspectives, including a multidisciplinary sport science approach using mixed methods. The theoretical standpoint in the sociocultural analyses is inspired by Bourdieu’s theories and concepts of habitus, capital, field and doxa, which are used as analytical tools. Different theories relating to the evaluation of movement abilities as product- or process oriented assessment are also made use of.Movement abilities tests and assessment tools are also found to construct a specific and narrow form of physical capital strongly related to traditional sports. Accordingly, the social construction of movement ability through assessment tools is far from neutral and could affect how children see themselves and their sense of ‘ability’. Furthermore, the assumption that an acquired high level of movement ability plays a central role for being physically active is challenged in the thesis. Even though pupils at the age of 15 had a low level of assessed movement ability, it did not prevent them from acquiring a taste for sport and physical activity later in life. However, more studies on movement ability and the underlining mechanisms and factors for engaging in physical activities are necessary.
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