| 1. |
- Santonen, Mikael, et al.
(author)
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Polycrystalline silicon, a molecular dynamics study : I. Deposition and growth modes
- 2024
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In: Modelling and Simulation in Materials Science and Engineering. - : Institute of Physics Publishing (IOPP). - 0965-0393 .- 1361-651X. ; 32:6
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Journal article (peer-reviewed)abstract
- Polycrystalline silicon (poly-Si) significantly expands the properties of the ICT miracle material, silicon (Si). Depending on the grain size and shape and grain boundary structure, the properties of poly-Si exceed what single-crystal (c-Si) and amorphous (a-Si) silicon can offer, especially for radio frequency (RF) applications in microelectronics. Due to its wide range of applications and, on the one hand, its theoretically and technologically challenging microstructure, poly-Si research is the most timely (Ding et al 2020 Mater. Charact. 161 110174; Zhao and Li 2019 Acta Mater. 168 52-62). In this report, we describe how we simulate and analyse the phenomena and mechanisms that control the effect of poly-Si deposition parameters on the structure of the deposited poly-Si films using classical molecular dynamics simulations. The grain shape and size, degree of crystallinity, grain boundary structure and the stress of poly-Si films are determined depending on the growth temperature, temperature distribution in the growing film, deposition flux, flux variation and the energy transferred to the film surface due to the deposition flux. The main results include: (i) the dependence of the crystallinity profile of the deposited poly-Si films on the stress, temperature and the different parameters of the deposition flux, (ii) growth modes at the early stages of the deposition, (iii) interaction and stability of seed crystallites at the early stage of the deposition of poly-Si films and the transition from the isolated crystallite growth to the poly-Si growth, (iv) interplay of the temperature, crystallinity, crystal shape and heath conductivity of different Si phases, (v) four different stages of crystallite growth are described: nucleation, growth, disappearance and retardation.
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| 2. |
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| 3. |
- Lahdelma, Risto, et al.
(author)
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Reference Point Approach for Multiple Decision Makers
- 2005
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In: European Journal of Operational Research. - : Elsevier BV. - 0377-2217 .- 1872-6860. ; 164:3, s. 785-791
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Journal article (peer-reviewed)abstract
- We consider multiple criteria decision-making problems where a group of decision-makers wants to find the most preferred solution from a discrete set of alternatives. We develop a method that uses achievement functions for charting subsets of reference points that would support a certain alternative to be the most preferred one. The resulting descriptive information is provided to the decision-makers in the form of reference acceptability indices and central reference points for each decision alternative. Then, the decision-makers can compare this information with their own preferences. We demonstrate the use of the method using a strategic multiple criteria decision model for an electricity retailer.
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| 4. |
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| 5. |
- Miettinen, Kaisa, 1965-, et al.
(author)
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Verbal Ordinal Classification with Multicriteria Decision Aiding
- 2008
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In: Central European Journal of Operations Research. - : Elsevier. - 1435-246X .- 1613-9178 .- 0377-2217. ; 185:3, s. 964-983
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Journal article (peer-reviewed)abstract
- Professionals in neuropsychology usually perform diagnoses of patients behaviour in a verbal rather than in a numerical form. This fact generates interest in decision support systems that process verbal data. It also motivates us to develop methods for the classification of such data. In this paper, we describe ways of aiding classification of a discrete set of objects, evaluated on set of criteria that may have verbal estimations, into ordered decision classes. In some situations, there is no explicit additional information available, while in others it is possible to order the criteria lexicographically. We consider both of these cases. The proposed Dichotomic Classification (DC) method is based on the principles of Verbal Decision Analysis (VDA). Verbal Decision Analysis methods are especially helpful when verbal data, in criteria values, are to be handled. When compared to the previously developed Verbal Decision Analysis classification methods, Dichotomic Classification method performs better on the same data sets and is able to cope with larger sizes of the object sets to be classified. We present an interactive classification procedure, estimate the effectiveness and computational complexity of the new method and compare it to one of the previously developed Verbal Decision Analysis methods. The developed and studied methods are implemented in the framework of a decision support system, and the results of testing on artificial sets of data are reported.
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| 6. |
- Miettinen, Teemu, et al.
(author)
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Pain interference type and level guide the assessment process in chronic pain : Categorizing pain patients entering tertiary pain treatment with the Brief Pain Inventory
- 2019
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In: PLOS ONE. - : PLOS. - 1932-6203. ; 14:8
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Journal article (peer-reviewed)abstract
- Chronic pain patients enter treatment with different problem profiles making careful assessment a necessity for more individualized treatment plans. In this cross-sectional study we assigned 320 patients entering tertiary multidisciplinary pain treatment into four categories based on whether they scored low or high on the activity and the affective pain interference dimensions of the Brief Pain Inventory (BPI). To determine whether this categorization system delineates issues that should be assessed further, the categories were compared with ANOVA and MANOVA analyses on three domains: variables affecting physical well-being (body mass index, exercise, substance use), psychological resources (mood), and pain-specific psychological factors (pain anxiety, pain acceptance). The results indicated that subjects who scored low on both interference dimensions compared similarly in weight: mean Body Mass Index (BMI) 27.0 (SD 6.0) kg/m2, and exercise: mean of 2.4 (SD 1.7) exercising sessions over 20 minutes per week, to the general population, had no depressive symptoms on average: mean Beck Depression Index II (BDI-II) score 11.7 (SD 7.5), and had the most favorable psychological reactions to pain relative to the other categories: mean total Pain Anxiety Symptoms Scale-20 (PASS-20) score 36.4 (SD 17.9). In contrast, when interference was high on activity, more physical well-being problems were evident e.g. weight: mean BMI 31.0 (SD 7.3) kg/m2, diminished exercise: mean of 1.5 (SD 1.6) exercising sessions per week, and avoidance behavior: mean PASS-20 Escape/Avoidance subscale 3.7 (95% CI: 1.7 to 5.8) scores higher in comparison to activity interference remaining low. With high affective interference, more depressive symptoms: mean BDI-II score 17.7 (SD 7.3), and more cognitive pain anxiety: mean PASS-20 Cognitive Anxiety subscale 2.8 (95% CI 0.7 to 4.8) scores higher in comparison to affective interference remaining low, emerged. Having high interference on both dimensions indicated accumulated risks for reduced physical well-being: mean BMI 29.9 (SD 6.1) kg/m2, mean of 1.2 (SD 1.7) exercising sessions per week, mood problems: mean BDI-II 20.3 (SD 10.6), and negative psychological reactions to pain: mean total PASS-20 score 53.2 (18.4). The results suggest that low interference on both dimensions may allow assessment with only physician consultations, while high interference on either dimension may call attention to distinct issues to be addressed with the help of a physiotherapist or a psychologist, whereas high interference on both dimensions highlights the need for a full multidisciplinary assessment.
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| 7. |
- Miettinen, Teemu, et al.
(author)
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Sleep problems in pain patients entering tertiary pain care : the role of pain-related anxiety, medication use, self-reported diseases, and sleep disorders
- 2022
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In: Pain. - : Wolters Kluwer. - 0304-3959 .- 1872-6623. ; 163:7, s. e812-e820
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Journal article (peer-reviewed)abstract
- Chronic pain and sleep problems frequently co-occur. Pain itself disturbs sleep, but other factors may also contribute to sleep problems in pain patients. This cross-sectional study of 473 patients (69.9% female, mean age 47 years) entering tertiary pain management compared normally sleeping pain patients with those having recurring sleep problems to determine the relationship between pain and sleep. Groups were compared for pain and pain aetiology, pain-related anxiety, childhood adversities, use of sleep and pain medications, self-reported diseases, and sleep disorders. Further, the association of pain-related anxiety (cognitive anxiety, escape/avoidance, fear, and physiological anxiety) with more disturbing sleep problems was investigated in the whole cohort. The main results were that those with sleep problems more often reported multiple health conditions than those sleeping normally (depression 31.6% vs 5.0%; angina pectoris 6.5% vs 0.0%; asthma 19.6% vs 1.7%; low back problems 55.1% vs 23.3%; joint disease other than rheumatoid arthritis 32.3% vs 18.3%). Accumulations of five or more childhood adversities were more often present in those with sleep problems. Restless legs symptoms were more common in those with sleep problems than those sleeping normally (33.2% vs 11.7%). Patients having sleep problems reported more use of sleep and pain medications than those sleeping normally. Findings about pain-related anxiety suggest physiological reactions as significant factors for increased sleep disturbances. These factors need to be addressed in the management of the comorbidity of pain and sleep problems and research to understand mechanisms in these is sorely needed.
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| 8. |
- Thiele, Lothar, et al.
(author)
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A Preference-Based Evolutionary Algorithm for Multi-Objective Optimization
- 2009
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In: Evolutionary Computation. - : MIT Press - Journals. - 1063-6560 .- 1530-9304. ; 17:3, s. 411-436
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Journal article (peer-reviewed)abstract
- In this paper, we discuss the idea of incorporating preference information into evolutionary multi-objective optimization and propose a preference-based evolutionary approach that can be used as an integral part of an interactive algorithm. One algorithm is proposed in the paper. At each iteration, the decision maker is asked to give preference information in terms of his or her reference point consisting of desirable aspiration levels for objective functions. The information is used in an evolutionary algorithm to generate a new population by combining the fitness function and an achievement scalarizing function. In multi-objective optimization, achievement scalarizing functions are widely used to project a given reference point into the Pareto optimal set. In our approach, the next population is thus more concentrated in the area where more preferred alternatives are assumed to lie and the whole Pareto optimal set does not have to be generated with equal accuracy. The approach is demonstrated by numerical examples.
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| 9. |
- Thiele, Lothar, et al.
(author)
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A Preference-Based Interactive Evolutionary Algorithm for Multiobjective Optimization
- 2007
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Reports (other academic/artistic)abstract
- In this paper, we discuss ideas of incorporating preference information intoevolutionary multiobjective optimization and propose a preference-based evolutionaryalgorithm that can be used as an integral part of an interactive algorithm that we alsointroduce. At each iteration of the interactive algorithm, the DM is asked to givepreference information in terms of his/her reference point consisting of desirableaspiration levels for objective functions. The information is used in an evolutionaryalgorithm that generates a new population by combining the fitness function with anachievement scalarizing function containing the reference point. In the field ofmultiple criteria decision making, achievement scalarizing functions are widely usedfor projecting the reference point into the Pareto optimal set. In our approach, the nextpopulation is more concentrated in the area where more preferred alternatives areassumed to lie and the whole Pareto optimal set does not have to be generated withequal accuracy. The approach is demonstrated by numerical examples.
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| 10. |
- Yevseyeva, Iryna, et al.
(author)
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SMAA-Classification - A New Method for Nominal Classification
- 2007
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Reports (other academic/artistic)abstract
- We have developed a multicriteria decision aiding method for nominal classification for situations where prefer-ence information is imprecise, uncertain or absent. Such situations may appear, for instance, when the decisionmaker is not sure about his or her preferences or when there are multiple decision makers who have difficulties inagreeing about their common preference. The new SMAA-Classification method extends Stochastic Multicrite-ria Acceptability Analysis (SMAA) methodology for classification problems. The method provides the decisionmaker with descriptive information in the form of acceptability index for each alternative to be classified intoeach predefined class. We test the new method with several applications.
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