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A Simple Registration Algorithm for Different Time Domains of Functional Data
Kyungmin Ahn 계명대학교 자연과학연구소 2022 Quantitative Bio-Science Vol.41 No.2
In Functional Data Analysis, functional data contains two types of variabilities: amplitude or vertical variability and phase or horizontal variability. Particularly for Functional Data Analysis, phase variation is a crucial noise and this is due to the lack of registration between peaks or valleys. Many registration or alignment algorithms have been proposed to reduce the phase variation between curves. However, these methods are restricted to the same fixed time intervals, that is, the functional observations are defined on the same fixed time domains. However, owing to the lack of synchronization, several functional data can be observed at different time intervals. In this study, we proposed a functional linear registration algorithm using a simple linear equation to align the functional data, which can also handle the different time intervals of functions. We demonstrated the framework using simulated data and real data to assess the algorithm’s effectiveness.
Optimal Design Methodology of Multiwidth HTS Magnet for Minimum Wire Consumption
Ahn, Min Cheol,Yang, Hongmin,Kim, Kyungmin,Jang, Jae Young,Lee, SangGap,Hahn, Seungyong Institute of Electrical and Electronics Engineers 2018 IEEE transactions on applied superconductivity Vol.28 No.3
<P>This paper investigates an optimal design methodology for multiwidth (MW) high-temperature superconductor (HTS) magnets, where pancake coils wound with the narrowest tapes were placed at and near the magnet center and those with progressively wider tapes toward the top and bottom of the magnet. For a given design, target of field strength and winding bore, input parameters include tape width, number of grading tapes, and number of pancakes coils, while the main objective is to minimize the magnet volume, i.e., essentially the stored energy and thus the cost. A magnet with a single-width tape is also designed as a control sample for comparison. A case study on a design of 3-T 240-mm HTS magnet was carried out. In that case, MW magnets save 40% wire consumption of single-width magnets. The results are expected to be beneficial to determine the practical level of HTS tape grading and estimate a volume of an MW magnet.</P>
Ahn Jisung,Lee Sang Won,Kim Kyungmin,Jin Bohyun,Chung Un Sun 대한의학회 2023 Journal of Korean medical science Vol.38 No.37
Background: Loss of companion animals can result in various psychological reactions, including complicated grief, depression, anxiety, and insomnia. However, research on the prevalence of patients requiring clinical intervention is limited. Moreover, research examining the relationship between childhood trauma and psychological symptoms after pet loss is lacking. Therefore, this study aimed to investigate the rates of clinically significant psychological distress after pet loss and the impact of childhood trauma on adults who have experienced pet loss. Methods: An online survey was conducted with non-clinical adult participants who had experienced the loss of a companion animal. Psychiatric characteristics were evaluated using standardized assessments, including the Inventory of Complicated Grief (ICG), the Patient Health Questionnaire-9 (PHQ-9), the Generalized Anxiety Disorder-7 (GAD-7), and the Insomnia Severity Index (ISI). Childhood trauma was evaluated using the Childhood Trauma Questionnaire (CTQ). Results: In a sample of 137 individuals who had experienced pet loss, the percentages of those who exceeded the cutoff points were 55% for the ICG, 52% for the PHQ-9, 40% for the GAD-7, and 32% for the ISI. The group that reported childhood trauma exhibited significantly higher scores on the ICG (t = 2.16, P = 0.032), PHQ-9 (t = 3.05, P = 0.003), GAD-7 (t = 2.61, P = 0.010), and ISI (t = 2.11, P = 0.037) than in the group without childhood trauma. For participants who experienced pet loss for less than one year, there was no significant difference in the ICG between the trauma and non-trauma groups, as both had extremely high scores. However, the trauma group had a significantly higher PHQ-9 (t = 2.58, P = 0.012) than the non-trauma group. In contrast, for participants who experienced pet loss for more than one year, the trauma group had a significantly higher ICG (t = 2.22, P = 0.03) than the non-trauma group, while there was no significant difference in the PHQ-9. Additionally, the emotional abuse scores on the CTQ were most significantly correlated with the ICG scores even after controlling for depressive symptoms. Conclusion: People who experienced pet loss had significant psychological symptoms, ranging from 32% to 55%. Childhood trauma experiences affect complicated grief, depressive symptoms, anxiety symptoms, insomnia and prolonged grief disorder after pet loss. After pet loss, people with childhood trauma may require more psychological help than those without trauma.
A STUDY ON METHODOLOGY FOR IDENTIFYING CORRELATIONS BETWEEN LERF AND EARLY FATALITY
Kang, Kyungmin,Jae, Moosung,Ahn, Kwang-Il Korean Nuclear Society 2012 Nuclear Engineering and Technology Vol.44 No.7
The correlations between Large Early Release Frequency (LERF) and Early Fatality need to be investigated for risk-informed application and regulation. In Regulatory Guide (RG) -1.174, while there are decision-making criteria using the measures of Core Damage Frequency (CDF) and LERF, there are no specific criteria on LERF. Since there are both huge uncertainties and large costs needed in off-site consequence calculation, a LERF assessment methodology needs to be developed, and its correlation factor needs to be identified, for risk-informed decision-making. A new method for estimating off-site consequence has been presented and performed for assessing health effects caused by radioisotopes released from severe accidents of nuclear power plants in this study. The MACCS2 code is used for validating the source term quantitatively regarding health effects, depending on the release characteristics of radioisotopes during severe accidents. This study developed a method for identifying correlations between LERF and Early Fatality and validates the results of the model using the MACCS2 code. The results of this study may contribute to defining LERF and finding a measure for risk-informed regulations and risk-informed decision-making.