Approach and application to transfer heterogeneous simulation data from finite element analysis to neural networks

Tobias C. Spruegel,Sebastian Bickel,Benjamin Schleich,Sandro Wartzack 한국CDE학회 2021 Journal of computational design and engineering Vol.8 No.1

The simulation of product behavior is a vital part of current virtual product development. It can be expected that soon there will be more product simulations due to the availability of easy-to-use finite element analysis software and computational power. Consequently, the amount of accessible new simulation data adds up to the already existing amount. However, even when using easy-to-use finite element software tools, errors can occur during the setup of finite element simulations, and users should be warned about certain mistakes by automatic algorithms. To use the vast amount of available finite element simulations for a data-driven finite element support tool, in this paper, a methodology will be presented to transform different finite element simulations to unified matrices. The procedure is based on the projection of nodes onto a detector sphere, which is converted into a matrix in the next step. The generated matrices represent the simulation and can be described as the DNA of a finite element simulation. They can be used as an input for any machine learning model, such as convolutional neural networks. The essential steps of preprocessing the data and an application with a large dataset are part of this contribution. The trained network can then be used for an automatic plausibility check for new simulations, based on the previous simulation data from the past. This can result in a tool for automatic plausibility checks and can be the backbone for a feedback system for less experienced users.

Control Allocation for Double-ended Ferries with Full-scale Experimental Results

Tobias R. Torben,Astrid H. Brodtkorb,Asgeir J. Sørensen 제어·로봇·시스템학회 2020 International Journal of Control, Automation, and Vol.18 No.3

A novel control allocation algorithm for double-ended ferries with symmetrical thruster configuration is proposed. The allocation problem is formulated using the extended thrust representation, resulting in a four dimensional constrained optimization problem. Using the thrust configuration constraint, the optimization problem is reduced to a scalar bounded optimization problem, for which there exists fast solvers. We propose a cost function and bounds such that the allocation algorithm supports the standard way of performing manual thruster control on ferries. The real-time performance of the proposed algorithm is demonstrated in a simulation study, and in full-scale experiments.

Changes of hemodynamic and cerebral oxygenation after exercise in normobaric and hypobaric hypoxia

Tobias Kammerer,Valentina Faihs,Nikolai Hulde,Andreas Bayer,Max Hubner,Florian Brettner,Walter Karlen,Julia Maria Kropfl,Markus Rehm,Christina Spengler,Simon Thomas Schafer 대한직업환경의학회 2019 대한직업환경의학회지 Vol.30 No.-

Objective: Normobaric (NH) and hypobaric hypoxia (HH) are associated with acute mountain sickness (AMS) and cognitive dysfunction. Only few variables, like heart-rate-variability, are correlated with AMS. However, prediction of AMS remains difficult. We therefore designed an expedition-study with healthy volunteers in NH/HH to investigate additional non-invasive hemodynamic variables associated with AMS. Methods: Eleven healthy subjects were examined in NH (FiO2 13.1%; equivalent of 3.883 m a.s.l; duration 4 h) and HH (3.883 m a.s.l.; duration 24 h) before and after an exercise of 120 min. Changes in parameters of electrical cardiometry (cardiac index (CI), left-ventricular ejection time (LVET), stroke volume (SV), index of contractility (ICON)), near-infrared spectroscopy (cerebral oxygenation, rScO2), Lake-Louise-Score (LLS) and cognitive function tests were assessed. One-Way-ANOVA, Wilcoxon matched-pairs test, Spearman’s-correlation-analysis and Student’s t-test were performed. Results: HH increased heart rate (HR), mean arterial pressure (MAP) and CI and decreased LVET, SV and ICON, whereas NH increased HR and decreased LVET. In both NH and HH cerebral oxygenation decreased and LLS increased significantly. After 24 h in HH, 6 of 11 subjects (54.6%) developed AMS. LLS remained increased until 24 h in HH, whereas cognitive function remained unaltered. In HH, HR and LLS were inversely correlated (r = − 0.692; p < 0.05). More importantly, the rScO2-decrease after exercise in NH significantly correlated with LLS after 24 h in HH (r = − 0.971; p < 0.01) and rScO2 correlated significantly with HR (r = 0.802; p < 0.01), CI (r = 0.682; p < 0.05) and SV (r = 0.709; p < 0.05) after exercise in HH. Conclusions: Both acute NH and HH altered hemodynamic and cerebral oxygenation and induced AMS. Subjects, who adapted their CI had higher rScO2 and lower LLS. Furthermore, rScO2 after exercise under normobaric conditions was associated with AMS at high altitudes.

Changes of hemodynamic and cerebral oxygenation after exercise in normobaric and hypobaric hypoxia

Tobias Kammerer,Valentina Faihs,Nikolai Hulde,Andreas Bayer,Max Hubner,Florian Brettner,Walter Karlen,Julia Maria Kropfl,Markus Rehm,Christina Spengler,Simon Thomas Schafer 대한직업환경의학회 2018 대한직업환경의학회지 Vol.30 No.-

Objective: Normobaric (NH) and hypobaric hypoxia (HH) are associated with acute mountain sickness (AMS) and cognitive dysfunction. Only few variables, like heart-rate-variability, are correlated with AMS. However, prediction of AMS remains difficult. We therefore designed an expedition-study with healthy volunteers in NH/HH to investigate additional non-invasive hemodynamic variables associated with AMS. Methods: Eleven healthy subjects were examined in NH (FiO₂ 13.1%; equivalent of 3.883 m a.s.l; duration 4 h) and HH (3.883 m a.s.l.; duration 24 h) before and after an exercise of 120 min. Changes in parameters of electrical cardiometry (cardiac index (CI), left-ventricular ejection time (LVET), stroke volume (SV), index of contractility (ICON)), near-infrared spectroscopy (cerebral oxygenation, rScO₂), Lake-Louise-Score (LLS) and cognitive function tests were assessed. One-Way-ANOVA, Wilcoxon matched-pairs test, Spearman’s-correlation-analysis and Student’s t-test were performed. Results: HH increased heart rate (HR), mean arterial pressure (MAP) and CI and decreased LVET, SV and ICON, whereas NH increased HR and decreased LVET. In both NH and HH cerebral oxygenation decreased and LLS increased significantly. After 24 h in HH, 6 of 11 subjects (54.6%) developed AMS. LLS remained increased until 24 h in HH, whereas cognitive function remained unaltered. In HH, HR and LLS were inversely correlated (r = − 0.692; p < 0.05). More importantly, the rScO2-decrease after exercise in NH significantly correlated with LLS after 24 h in HH (r = − 0.971; p < 0.01) and rScO2 correlated significantly with HR (r = 0.802; p < 0.01), CI (r = 0.682; p < 0.05) and SV (r = 0.709; p < 0.05) after exercise in HH. Conclusions: Both acute NH and HH altered hemodynamic and cerebral oxygenation and induced AMS. Subjects, who adapted their CI had higher rScO2 and lower LLS. Furthermore, rScO2 after exercise under normobaric conditions was associated with AMS at high altitudes.

Ch’oe Namsǒn and Identity Construction through Negotiation with the Colonizer

Tobias Scholl 고려대학교 한국사연구소 2019 International Journal of Korean History Vol.24 No.1

This paper takes a closer look at Ch’oe Namsŏn’s construction of Korean identity during the colonial period. Ch’oe was ambiguous towards Japan, seeing it as many other intellectuals did, as a model for Korea’s modernization, and was aware that Japan would be both Korea’s “oldest friend” and “biggest obstacle” in this regard. After his imprisonment for his role in the Korean independence movement in 1919, he started to cooperate with the Japanese to influence colonial knowledge production and therefore decided to “negotiate” directly with the colonizer. In his “Treatise on Purham culture,” Ch’oe included Japan in the same cultural sphere and saw it as less of Other than the West and China. While his theses and arguments were based on Japanese research and written in Japanese, Ch’oe maintained a Korean identity within the colonial setting not by a “negation” of Japanese research, but by “negotiation” through its reinterpretation and autoethnography. Due to his referring to Japanese scholars and due to the ambiguity of his mimicry his work can be considered “at once resemblance and menace,” and simultaneously as collaboration and resistance.

Transverse Flux Machine Optimization by 2D FEM Program

Tobias Schmalen,DOHYUN KANG(강도현),JIYOUNG LEE(이지영) 대한전기학회 2016 대한전기학회 학술대회 논문집 Vol.2016 No.3

This paper presents the development of optimizations of a Transversal Flux Permanent Magnet Machine with different variations of the ratio between stator teeth width and pole pitch width and variation of the ratio permanent magnet thickness to pole pitch width. A comparison of using different core materials and different permanent magnets, Also a variation of the airgap and changing of the applied current shape-either DC or sinusoidal- will be made. All comparisons will be based on thrust force density simulated by 2D FEM program.

Reliability and Validity of the Embouchure Dystonia Severity Rating Scale

Tobias Mantel 대한파킨슨병및이상운동질환학회 2023 Journal Of Movement Disorders Vol.16 No.2

Embouchure dystonia (ED) is a task-specific movement disorder that leads to loss of fine motor control of the embouchure and tongue muscles in wind musicians. In contrast to musicians’ hand dystonia, no validated severity rating for ED exists, posing a major obstacle for structured assessment in scientific and clinical settings. The aim of this study is to validate an ED severity rating scale (EDSRS) allowing for a standardized estimation of symptom severity in ED.

Macromolecular nanoelectronics

Tobias Nyberg,Fengling Zhang,Olle Ingan?s 한국물리학회 2002 Current Applied Physics Vol.2 No.1

We have explored new organic materials and fabrication methods to fabricate organic photodiodes and light emitting diodes. Grafting of a fullerene derivative to a polythiophene backbone yielded an integrated acceptor-donor polymer that we used as the active material in organic photodiodes. Using a method of soft lithography, soft embossing, we fabricated submicron structures to be used as organic light emitting diodes. Employing a silicone rubber replica (stamp) of an optical diffraction grating we transferred the grating pattern to an organic resist layer by placing the stamp in conformal contact with the resist. The transferred pattern was subsequently used as an etch mask for the processing of the device. The structures were successfully utilized as light emitting diodes and photodiodes, with device characteristics influenced by the imposed structure. 2002 Published by Elsevier Science B.V.

A Stable Peninsula in an Unstable World: How Russia’s Invasion of Ukraine Increases Korean Security

Tobias Dahlqvist,백선우 통일연구원 2023 International journal of korean unification studie Vol.32 No.2

This article examines how Russia’s invasion of Ukraine impacts peace and security on the Korean Peninsula. Drawing on some neorealist theories of international relations, the article argues that Russia’s war in Ukraine has reduced the likelihood of military conflict between North and South Korea. This is because Russian aggression has rapidly accelerated a division between two security blocs in East Asia, one comprising South Korea, the United States, and Japan, and one comprising North Korea, Russia, and China, and this division contributes to regional stability in two ways. First, an unambiguous division of East Asia creates a bipolar region, and a balance of power between the two blocs can be maintained. This article examines how Russia’s invasion of Ukraine impacts peace and security on the Korean Peninsula. Drawing on some neorealist theories of international relations, the article argues that Russia’s war in Ukraine has reduced the likelihood of military conflict between North and South Korea. This is because Russian aggression has rapidly accelerated a division between two security blocs in East Asia, one comprising South Korea, the United States, and Japan, and one comprising North Korea, Russia, and China, and this division contributes to regional stability in two ways. First, an unambiguous division of East Asia creates a bipolar region, and a balance of power between the two blocs can be maintained.

Cross-Cultural Management in China

Tobias Cramer 한국유통과학회 2018 Asian Journal of Business Environment (AJBE) Vol.8 No.1

Purpose - This paper discusses cross-cultural management (CCM) in China and how its business students get prepared by university cross-cultural management courses for an international market. Research design, data, and methodology – It was therefore decided to do an online content analysis looking at CCM courses offered by a number of Chinese universities first, and second to conduct a quantitative survey on CCM courses as well as topics among Chinese undergraduate business students at a large Eastern Chinese university. Results - From fundamental aspects, seven Chinese cultural standards emerge which highly influence the behaviour of the Chinese. There is a tendency to imply the integration of not only local but also cross cultural issues in academic management courses. Besides Hong Kong, there are currently 17 Chinese universities and schools accredited by the Association to Advance Collegiate Schools of Business (AACSB) that explicitly requires cross-cultural management competencies in undergraduate and graduate degree programmes. In addition, the study confirmed that two-third of the sample (Chinese undergraduate business students) had taken cross-cultural management courses. Conclusions - The results of this research have made it clear that Chinese universities and schools are aware of the importance of cross-cultural management competencies.