| 5121. |
- Jonsson, Magnus, 1969-, et al.
(författare)
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Wired and wireless reliable real-time communication in industrial systems
- 2010
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Ingår i: Factory Automation. - Vienna, Austria : IN-TECH. - 9789533070247 ; , s. 161-176
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- In modern factory automation systems, data communication plays a vital role. Different nodes like control systems, sensors and actuators can communicate over a wireless or wired industrial network. The data traffic generated is often scheduled for periodic transmission, where each single message or packet must arrive in time. For this real-time communication, methods have been developed to support communication services with a guaranteed throughput and delay bound for such periodic traffic, but merely under the assumption of error-free communication. However, the possibility for errors in the transmission still exists due to, e.g. noise or interference. A node receiving sensor values from a sensor in the system might then be forced to rely upon an older sensor value from the latest period, possibly leading to inaccuracies in control loops which can compromise the functioning of the system. In safety-critical systems, redundant networks or communication channels are frequently added to cope with errors, leading to more expensive systems. In this chapter, we will describe an alternative approach where erroneous data packets are retransmitted in a way that does not jeopardise any earlier stated real-time guarantees for ordinary transmissions. Using our framework, the reliability of real-time communication can be increased in a more cost-efficient way. We describe in this chapter an overview of our framework for reliable real-time communication, while details of our approach can be found in our earlier publications. In the light of the emerging use of wireless communication, the framework proves to be especially useful due to the high bit error rate inherent to the wireless medium. However, the framework is naturally also attractive for wired communication systems.
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| 5122. |
- Jonsson, Per, 1981, et al.
(författare)
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Laser hardened trimming tools : wear test and geometry evaluation
- 2008
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Ingår i: Proceedings of the IDDRG 2008 Conference. - Olofström : Industriellt utvecklingscentrum i Olofström AB. - 9789163329487 ; , s. 639-650
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Konferensbidrag (refereegranskat)abstract
- The higher product requirements (reduced weight, increased safety, lower emissions…) have meant that a larger number of car body parts must be made in advanced high strength steels. With a reduced lifecycle of a car model from 7 to 5 years this leads to a need for reducing the manufacturing cost and lead time for the tool and die design and manufacturing. The main purpose of this investigation is to establish cost- and lead-time reducing guidelines for selection of tool concepts (choice of die materials, hardening methods and geometry) for different production volume scenarios with respect to sheet materials quality (MS-UHSS) and thickness, without increased die maintenance costs. In this study the cutting edge geometry has been evaluated in respect to the cutting edge radius and the angle of the upper tool. Experimental testing together with FE simulation has been used. Results show that an angle of 93° on the upper cutting edge initially can reduce the cutting work by 14%. Results also shows that by using a cutting edge radius of 80µm, the tool “wear in phase” can be more controlled. Wear test up to 150 000 strokes have been made to evaluate different tool concepts using laser hardened cast iron, cast steel and wrought steel as die material. Sheet material tested was 220RP, DP600, DP800, 700MC and DP1000, with a thickness of t=2mm. The result leads to recommendations for industrial verification. Results among other recommendations are: laser hardened EN-JS-2070 up to 500 000 parts against 220RP and Sleipner up to 1 500 000 parts against 1000DP.
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| 5123. |
- Jonsson, Per, 1981, et al.
(författare)
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Surface Topography on trimming dies and the influence of wear
- 2010
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Ingår i: Proceedings of the International Deep Drawing Research Group. - 9783851251081 ; , s. 345-354
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Konferensbidrag (refereegranskat)abstract
- In this paper it is investigated how surface topography on trimming dies influences the wear process. Surfaces on both semi-industrial test dies and dies used in production were analyzed with different surface topography analysis methods. The result shows that the wear process is different on the different sides of the trimming edge. The texture direction of the surface is changed due to wear, with the strongest change on the clearance side of the edge. The roughness on sheet side of the edge is reduced due to a hammering effect from the sheet material. The result on the test dies and the production dies correlates well.
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| 5124. |
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| 5125. |
- Jordalen, Gro, et al.
(författare)
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The Role of Self-Control and Motivation on Exhaustion in Youth Athletes : A Longitudinal Perspective
- 2018
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Ingår i: Frontiers in Psychology. - Lausanne : Frontiers Media S.A.. - 1664-1078. ; 9
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Tidskriftsartikel (refereegranskat)abstract
- The depletion of self-control competencies has been explained by an external shift in motivation, and recent research has emphasized that controlled types of motivation and self-control competencies are positively associated with exhaustion in youth athletes. Using the self-determination theory and self-control theories, this study examined associations between athletes’ motivation, self-control competencies, and exhaustion experiences throughout a competitive season. A total of 321 winter sport youth athletes (173 males, 98 females, and 50 unknown gender; aged 16 to 20 years, M = 17.98, SD = 0.89) participated in this 10-week longitudinal study, including three time points. Using Bayesian structural equation modeling, associations between athletes’ reported level of motivation regulations, self-control, and exhaustion throughout their competitive season were examined in two mediation models. Constructs were associated in a conceptual and consistent manner. Simple mediation models showed credible indirect and direct effects of motivation on exhaustion via self-control within amotivation, and intrinsic, integrated, identified, and external regulation analyses. These credible effects were not replicated in the focused mediation model, when controlling for self-control and exhaustion autoregressive effects. However, direction of effects in both models was consistent and congruent. Findings consistently supported the interplay between motivation and exhaustion via self-control in youth athletes over an important competition period of the year. Autonomous and controlled motivation interacted with self-control and respectively predicted perceived exhaustion negatively and positively. Thus, autonomous self-control motives are important in preventing negative sport participation development over time. However, simple and focused mediation models showed different results, suggesting a necessity for accurate considerations of analytical methods chosen to investigate longitudinal mediation. Specifically, future studies need to carefully consider the time interval between measurement time points when investigating changes in dynamic psychological constructs, and include autoregressive longitudinal effects in order to predict change in levels of the outcome over time. © 2018 Jordalen, Lemyre, Solstad and Ivarsson.
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| 5126. |
- Jordalen, Gro, et al.
(författare)
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The Temporal Ordering of Motivation and Self-Control : A Cross-Lagged Effects Model
- 2020
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Ingår i: Journal of Sport & Exercise Psychology (JSEP). - Champaign : Human Kinetics. - 0895-2779 .- 1543-2904. ; 42:2, s. 102-113
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Tidskriftsartikel (refereegranskat)abstract
- Mechanisms leading to cognitive energy depletion in performance settings such as high-level sports highlight lijjjkely associations between individuals’ self-control capacity and their motivation. Investigating the temporal ordering of these concepts combining self-determination theory and psychosocial self-control theories, the authors hypothesized that athletes’ self-control capacity would be more influenced by their motivation than vice versa and that autonomous and controlled types of motivation would predict self-control capacity positively and negatively, respectively. High-level winter-sport athletes from Norwegian elite sport colleges (N = 321; 16–20 years) consented to participate. Using Bayesian structural equation modeling and 3-wave analyses, findings revealed credible self-control → motivation → self-control cross-lagged effects. Athletes’ trait self-control especially initiated the temporal ordering of the least controlled types of motivation (i.e., intrinsic, integrated, and amotivation). Findings indicate that practicing self-control competencies and promoting athletes’ autonomous types of motivation are important components in the development toward the elite level. These components will help athletes maintain their persistent goal striving by increasing the value and inherent satisfaction of the development process, avoiding the debilitating effects of self-control depletion and exhaustion. © 2020 Human Kinetics, Inc.
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| 5127. |
- Jordet, Geir, et al.
(författare)
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Scanning, Contextual Factors, and Association With Performance in English Premier League Footballers : An Investigation Across a Season
- 2020
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Ingår i: Frontiers in Psychology. - Lausanne : Frontiers Media S.A.. - 1664-1078. ; 11
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Tidskriftsartikel (refereegranskat)abstract
- Scanning in football (soccer) denotes an active head movement where a player’s face is temporarily directed away from the ball to gather information in preparation for subsequently engaging with the ball. The aim of this study was to learn more about the ways that 27 elite professional football players in an English Premier League club use scanning in competitive matches, the conditions under which this behavior is exhibited, and the relationships between these behaviors and performance. Players were filmed across 21 matches, producing a total number of 9,574 individual ball possessions for analysis. Close-up video analyses of scanning show positional differences (with central midfielders and central defenders scanning most frequently, forwards least) and contextual differences (with relatively lower scanning frequency in situations with tight opponent pressure, in positions wide in the field and closer to the opponent’s goal, and under certain game state conditions). Players scan more frequently prior to giving passes than when they dribble, shoot, or only receive it, as well as prior to more long/forward passes compared to short/backward ones, although these differences are small. A Bayesian hierarchical model, which accounts for individual player differences and pass difficulty, suggests that the more a player scans, the higher the probability of completing a pass. In conclusion, match demands are likely to constrain the extent to which highly elite players scan, and scanning seems to have a small, but positive role in elite football players’ performance. © 2020 Jordet, Aksum, Pedersen, Walvekar, Trivedi, McCall, Ivarsson and Priestley.
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| 5128. |
- Joris, Willem, et al.
(författare)
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IM2MEDIATE : Image of Immigrants in Media: Thought-provoking Effects: Final Report
- 2020
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The topic of migration has become particularly contentious in national as well as international debates. Media have a discernable impact on overall societal attitudes towards this phenomenon. Polls show time and again that immigration is one of the main issues occupying people’s minds. IM2MEDIATE (Images of Immigrants in the Media: Thought-provoking) examines the dynamic interplay between media representations of immigrants and refugees on the one hand, and the governmental and societal (re)actions to these on the other hand. Largely focusing on Belgium and Sweden, our interdisciplinary research attempts to unravel the determinants of people’s preferences regarding migration policy, expectations towards immigrants, and economic, humanitarian and cultural concerns about immigration’s effect on the life of the majority population. Whilst immigrants and refugees remain voiceless and highly underrepresented in the legacy media, IM2MEDIATE allows their voices to be heard.
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| 5129. |
- Joris, Willem, et al.
(författare)
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Refugees in the News : Content Analysis of Belgian and Swedish Media News
- 2017
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Ingår i: Migration and Communication Flows. ; , s. 36-36
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Konferensbidrag (refereegranskat)abstract
- As previous research showed a significant effect of news coverage about the migration issue on the public opinion, it is recommended to investigate how the refugees are portrayed in the news. Our content analysis of Belgian and Swedish newspapers, television news and online news before and after a carefully selected set of key moments between 2015 and 2017 includes responsibility indicators and suggested solution items, the gender structure of news items and news actors, collective actors versus individual actors, and the religious and national identity of the actors covered. Comparisons between the representations of blame attribution, demography, geographic identities, religious identities and degrees of individuation will be compared with real world indicators (such as statistics about the population of refugees and its composition in different subgroups and the evolution of these statistics).
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| 5130. |
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