| 1. |
- Cheng, Lihong, et al.
(author)
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Model abstraction for discrete-event systems by binary linear programming with applications to manufacturing systems
- 2021
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In: Science Progress. - : Sage Publications. - 0036-8504 .- 2047-7163. ; 104:3
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Journal article (peer-reviewed)abstract
- Model abstraction for finite state automata is helpful for decreasing computational complexity and improving comprehensibility for the verification and control synthesis of discrete-event systems (DES). Supremal quasi-congruence equivalence is an effective method for reducing the state space of DES and its effective algorithms based on graph theory have been developed. In this paper, a new method is proposed to convert the supremal quasi-congruence computation into a binary linear programming problem which can be solved by many powerful integer linear programming and satisfiability (SAT) solvers. Partitioning states to cosets is considered as allocating states to an unknown number of cosets and the requirement of finding the coarsest quasi-congruence is equivalent to using the least number of cosets. The novelty of this paper is to solve the optimal partitioning problem as an optimal state-to-coset allocation problem. The task of finding the coarsest quasi-congruence is equivalent to the objective of finding the least number of cosets. Then the problem can be solved by optimization methods, which are respectively implemented by mixed integer linear programming (MILP) in MATLAB and binary linear programming (BLP) in CPLEX. To reduce the computation time, the translation process is first optimized by introducing fewer decision variables and simplifying constraints in the programming problem. Second, the translation process formulates a few techniques of converting logic constraints on finite automata into binary linear constraints. These techniques will be helpful for other researchers exploiting integer linear programming and SAT solvers for solving partitioning or grouping problems. Third, the computational efficiency and correctness of the proposed method are verified by two different solvers. The proposed model abstraction approach is applied to simplify the large-scale supervisor model of a manufacturing system with five automated guided vehicles. The proposed method is not only a new solution for the coarsest quasi-congruence computation, but also provides us a more intuitive understanding of the quasi-congruence relation in the supervisory control theory. A future research direction is to apply more computationally efficient solvers to compute the optimal state-to-coset allocation problem.
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| 2. |
- Easterling, K.E., et al.
(author)
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The microstructure and properties of high Tc superconducting oxides
- 1990
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In: Science Progress. - 0036-8504 .- 2047-7163. ; 74:293, s. 69-90
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Journal article (peer-reviewed)abstract
- There has been considerable progress in producing and characterizing high Tc superconductors, but a number of materials science-related problems still exist, before their mechanical and electrical properties meet the requirements of many of the proposed applications. These materials are brittle, ceramic compounds with long unit cells that can be thought of as formed from layers of various oxides are an important common feature. The long unit cell structure leads to anisotropy in their electrical and mechanical properties, including the current carrying capacity or current density Jc. The crystallography and microstructure of the three major families of high Tc superconductors are reviewed and possible solutions to some of the materials problems are presented
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| 3. |
- Johansson, Anna, 1982-, et al.
(author)
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Patient-reported recovery in upper abdominal cancer surgery care : A prospective study
- 2021
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In: Science Progress. - : Sage Publications. - 0036-8504 .- 2047-7163. ; 104:2
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Journal article (peer-reviewed)abstract
- The study aimed to describe and analyse patient-reported recovery in patients after upper abdominal cancer surgery. This study had a quantitative design and patients were consecutively included in a university hospital in southern Sweden. Twenty-four patients answered the Postoperative Recovery Profile (PRP) questionnaire at three measurement points. All five dimensions were affected. In the physical symptoms dimension, the majority of patients reported a lack of energy upon discharge. High levels of anxiety were reported. Over 50% of patients reported some degree of depressed mood at all three measurement points. In the social dimension, the majority of patients reported some degree of being dependent on help from others in everyday life at 4?weeks after discharge. Few patients are fully recovered at 4?weeks after discharge. Individual patient-reported recovery estimates may be valuable in identifying and planning interventions tailored to each patients needs throughout the care process.
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| 4. |
- Rahimi, Fariba
(author)
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Towards a formal framework for integrated design-optimization and control of mechatronicsystems
- 2021
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In: Science Progress. - : SAGE Publications. - 0036-8504 .- 2047-7163. ; 104:4
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Research review (peer-reviewed)abstract
- This paper presents work towards a formal framework to support model-based integrated design and optimization of mechatronic products for early-phase conceptual design. This paper describes an integrated design framework through the introduction of its software implementation and a specific use case. The contribution is to introduce mathematical formalism to define the concepts, semantics, computation rules and system architectures of the formal framework. The advantage of the formal definitions is to clearly expose functionality and the limitations of the design framework and facilitate the software implementation. The modelling capability of the framework is enhanced to include non-linear mechatronic components, such as a two degrees-of-freedom arm. Further, an optimal proportional-integral-derivative control component is added to the software library supporting the framework.
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| 5. |
- Theorell, Tores, et al.
(author)
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The use of saliva steroids (cortisol and DHEA-s) as biomarkers of changing stress levels in people with dementia and their caregivers : A pilot study.
- 2021
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In: Science Progress. - : SAGE Publications. - 0036-8504 .- 2047-7163. ; 104:2
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Journal article (peer-reviewed)abstract
- The rationale was to explore the efficacy/sensitivity of using morning and evening cortisol levels as biomarkers for stress reduction in persons with dementia (PWDs) and their family caregivers (FCGs) participating in a music intervention program. Thirty-two PWD and their FGC were recruited to an 8-week, home-based music intervention program. Daily home-based collection of saliva samples took place at bedtime and upon awakening. Cortisol was analyzed in the morning and evening saliva samples and DHEA-s in the morning samples. Trends over 40 workdays (15-40 observations per subject) were assessed using linear regression analysis. Twenty-three PWD (72% of invited, 16 men and 7 women, age 69-93) and 24 caregivers (75%, 8 men and 16 women, age 37-90) completed the intervention for at least 6 weeks and were included in the analysis. One-fourth of the PWD and FCG had decreasing evening cortisol, accompanied by decreasing morning cortisol levels. In one-fourth of the participants the ratio between cortisol and DHEA-S in the morning samples was improved, indicating improved balance between energy mobilization and regeneration. Several participants showed no significant endocrine change. There was a statistically significant (two-sided test) correlation within the PWD-caregiver dyads in evening cortisol trend and a statistically significant decrease (two-sided test) in the morning-evening cortisol slope for the FCG group. Reduction in stress, as measured by evening cortisol, was observed in a substantial number of the participants. Recording endocrine stress is helpful for the unbiased assessment of the intervention.
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| 6. |
- Xu, Yin, et al.
(author)
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Systemic inflammation measured by erythrocyte sedimentation rate and cognitive function among young men in Sweden : A within-sibling analysis
- 2023
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In: Science Progress. - : Sage Publications. - 0036-8504 .- 2047-7163. ; 106:1
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Journal article (peer-reviewed)abstract
- This study assesses the extent to which the association between erythrocyte sedimentation rate, a marker of inflammation, and cognitive function is explained by shared familial factors using within-sibling analyses. Men who were born in Sweden between 1950 and 1965 and recorded in the Swedish Military Conscription Register between 1969 and 1983 were included (N = 632,396). Erythrocyte sedimentation rate and cognitive function were measured at the conscription assessment (median age = 18.3 years, with a range from 15.5 to 28.5 years). Conventional linear regression and multilevel linear regression with a hybrid modeling approach were used, with the latter to obtain within-effect estimation in which unmeasured familial confounding shared by siblings was controlled for. We found that the association between erythrocyte sedimentation rate and cognitive function at conscription assessment was partly accounted for by, but remained independent of, shared familial factors.
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