• Proceedings of the Korean Society for Quality Management Conference
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• 2006.04a
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• pp.80-85
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• 2006

HSS (high strength steel) is widely applied to reduce the weight but improve the strength in automobiles. This research has been peformed to secure a methodology to accurately predict the springback of HSS for successful tool and process designs in sheet stamping operations. We first peformed U-draw bending test to evaluate the springback characteristic. We then evaluated forming and springback processes using the 1-row model of the finite element method. Based on the peformance measure and parameters selected, extensive analyses of the factor effects on the springback have been made using experimental design concepts. We specifically selected Taguchi's orthogonal array, $L_{18}(2^1{\times}3^7)$, and the optimal level combination of the factors have been drawn from the analysis.

• Proceedings of the KIPE Conference
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• 2020.08a
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• pp.455-456
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• 2020

This paper proposes stability evaluation of DC/DC boost converters based on output impedance in harmonic transfer function matrix considering line impedance and cascaded voltage and current control loops. The harmonic state-space (HSS) model of converter and controller is developed to obtain the harmonic transfer function matrix of closed-loop output impedance. This work is useful for impedance-based stability analysis of converters connected to DC power systems.

• Journal of the Earthquake Engineering Society of Korea
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• v.21 no.3
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• pp.137-144
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• 2017

The cyclic behavior of braces is complex due to their asymmetric properties in tension and compression. For accurately simulating the cyclic curves of braces, it is important to predict the major parameters such as cyclic brace growth, cyclic buckling load, incidence local buckling and fracture with good precision. For a given brace, the most accurate values of these parameters can be estimated throughout experiments. However, it is almost impossible to conduct experiments whenever an analytical model has to be established for many braces in building structures due to enormous cost and time. For avoid such difficulties, empirical equations for predicting constituent parameters are proposed from regression analyses based on test results of various braces. This study focuses on rectangular hollow structural section(HSS) steel braces, which have been popularly used in construction practice owing to its sectional efficiency.

• Korean Medical Education Review
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• v.25 no.3
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• pp.212-228
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• 2023

Systems thinking, a linking domain of health systems science (HSS), is an approach that investigates specific problems from a holistic perspective. It supports improving patients' health, fulfilling their health needs, and anticipating issues that threaten patient safety within the healthcare system. It also helps solve problems through critical thinking and ref lection. This study aimed to develop an curriculum on systems thinking, explore the effectiveness of the course, and investigate the applicability of HSS education at individual universities. In this study, the ADDIE (Analysis, Design, Development, Implementation, and Evaluation) model was utilized to design, develop, implement, and evaluate an elective course on systems thinking. In the design process, learning outcomes and goals were developed, and educational content, teaching-learning methods, and student evaluation methods were linked. In the development process, class materials and evaluation materials were prepared. In the implementation process, the course was implemented, and the evaluation process analyzed the results of learning performance and curriculum assessments. The evaluation found the following results. First, the students in the study realized the importance of systems thinking and experienced the need for systems thinking through non-medical and medical situations. Second, the students were very satisfied with the learning activities in the course (mean=4.84), and the results of the self-competence evaluation, conducted before and after the course, also showed a significant improvement. This study confirmed the effectiveness of the elective course, and its results can serve as a reference for developing an HSS curriculum.

• Steel and Composite Structures
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• v.33 no.4
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• pp.489-507
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• 2019

In order to obtain high bearing capacity and good ductility simultaneously, a structural column with hybrid normal and high strength steel (HNHSS) welded box section has been developed. Residual stress is an important factor that can influence the behaviour of a structural member in steel structures. Accordingly, the magnitudes and distributions of residual stresses in HNHSS welded box sections were investigated experimentally using the sectioning method. In this study, the following four box sections were tested: one normal strength steel (NSS) section, one high strength steel (HSS) section, and two HNHSS sections. Based on the experimental data from previous studies and the test results of this study, the effects of the width-to-thickness ratio of plate, yield strength of plate, and the plate thickness of the residual stresses of welded box sections were investigated in detail. A unified residual stress model for NSS, HSS and HNHSS welded box sections was proposed, and the corresponding simplified prediction equations for the maximum tensile residual stress ratio (${\sigma}_{rt}/f_y$) and average compressive residual stress ratio (${\sigma}_{rc}/f_y$) in the model were quantitatively established. The predicted magnitudes and distributions of residual stresses for four tested sections in this study by using the proposed residual stress model were compared with the experimental results, and the feasibility of this proposed model was shown to be in good agreement.

• Journal of the Korean Society for information Management
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• v.37 no.3
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• pp.301-326
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• 2020

This study analyzed recent cases of transition to open access(OA) journals in humanities and social sciences(HSS) in foreign countries to find a way to transition to OA journals in Korea. Ling OA and UP led by researchers, OLH and KU led by libraries, S2O led by publishers and L+F model led by funders and libraries were analyzed. Programs by national funding agencies such as the Norwegian Research Council, Canada Social Sciences and Humanities Research Council, Austrian Science Fund, and Swiss Academy of Humanities and Social Sciences were also reviewed. Based on the results of the analyses, this study suggests for transition in Korean HSS field as follows; 1) transitions to open access journals in HSS should be supported at national level 2) the stakeholder in scholarly communications such as the nation, universities, libraries, research funders, scholarly societies etc has their own role in the transition but funders and libraries are the most important in financial support for open access publishing 3) but the financial support for the first stage of the transition should be done at national level 4) and open access journal publishing consortium comprised of libraries and information service institutions in the public sector such as KERIS, KISTI and the national library should be established 5) non commercial publishing platforms for scholarly societies should be developed and distributed.

• Journal of Pharmacopuncture
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• v.25 no.3
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• pp.258-267
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• 2022

Objectives: Hypertrophic scars (HSs) are caused by abnormal wound healing. To date, no standard treatment has been made available for HSs. Scrophularia striata has been reported to accelerate wound healing and has the potential to prevent HS formation. In this study, we investigated the anti-scarring effects of S. striata extract (SSE) in a rabbit ear model of scarring. Methods: In this study, New Zealand white rabbit (weight: 2.3-2.5 kg) were used. In the prevention phase of the study, three test groups received 5%, 10%, and 15% ointments of SSE in the Eucerin base, the fourth group received Eucerin, and the fifth group received no treatment. The samples were obtained on day 35 after wounding. In the treatment phase of the study, the test groups received an intralesional injection of SSE (5%, 10%, and 15%), the fourth group received an intralesional injection of triamcinolone, the fifth group received a solvent (injection vehicle), and the sixth group received no treatment. To evaluate the anti-scarring effects of SSE, the scar elevation index (SEI), epidermis thickness index (ETI), collagen deposition, and MMP2 and MMP9 gene expression were evaluated. Results: A significant reduction in SEI, ETI, and collagen deposition was noted in animals treated with SSE compared with the control groups. In addition, topical SSE stimulated MMP2 and MMP9 gene expression. Conclusion: The findings of this study demonstrate the potential for SSE in the prevention and treatment of HS. SSE could be prepared as an appropriate formulation to treat wounds and prevent abnormal scarring.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.10a
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• pp.961-964
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• 1995

For geometric accuracy in the net shape machining, the problem of tool deflection should be resolved in some fashion. In particular, this is crucial in finish cut operation where slim tools are used. The purpose of this paper is to verify the validity and effectiveness of the prediction model of the machined surface. Experimental results are presented for the cut of steel material with HSS endmill of diameter 6mm on machining center. The results shows that 1) the machining error due totool deflection is serious even in the low cutting load, 2) by using the mechanistic simulation model with experimental coefficients, the machining error was predicted with maximum prediction error of 10% which was significantly reduced to the desired level by the path modification method.

• Transactions of Materials Processing
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• v.22 no.1
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• pp.30-35
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• 2013

In this study, springback amounts of an S-rail are quantitatively compared according to the hardening model using a finite element simulation for the stamping process with high strength steels. For comparison of the hardening models, two types of hardening models were investigated. The two models were isotropic hardening and kinematic hardening. For the analysis with kinematic hardening, the Yoshida-Uemori model was selected. Five kinds of springback modes were measured at designated sections and a comparison was made between the experiment and the analyses with two types of hardening models. The analysis results show that the springback in the flange and the wall curl are predicted more accurately with a kinematic hardening model.

• Atmosphere
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• v.29 no.5
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• pp.671-687
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• 2019

This study evaluates the long-term seasonal predictability of summer (June, July and August) heatwaves over South Korea using 30-year (1989~2018) Hindcast data of the Pusan National University Coupled General Circulation Model (PNU CGCM)-Weather Research and Forecasting (WRF) chain. Heatwave indices such as Number of Heatwave days (HWD), Heatwave Intensity (HWI) and Heatwave Warning (HWW) are used to explore the long-term seasonal predictability of heatwaves. The prediction skills for HWD, HWI, and HWW are evaluated in terms of the Temporal Correlation Coefficient (TCC), Root Mean Square Error (RMSE) and Skill Scores such as Heidke Skill Score (HSS) and Hit Rate (HR). The spatial distributions of daily maximum temperature simulated by WRF are similar overall to those simulated by NCEP-R2 and PNU CGCM. The WRF tends to underestimate the daily maximum temperature than observation because the lateral boundary condition of WRF is PNU CGCM. According to TCC, RMSE and Skill Score, the predictability of daily maximum temperature is higher in the predictions that start from the February and April initial condition. However, the PNU CGCM-WRF chain tends to overestimate HWD, HWI and HWW compared to observations. The TCCs for heatwave indices range from 0.02 to 0.31. The RMSE, HR and HSS values are in the range of 7.73 to 8.73, 0.01 to 0.09 and 0.34 to 0.39, respectively. In general, the prediction skill of the PNU CGCM-WRF chain for heatwave indices is highest in the predictions that start from the February and April initial condition and is lower in the predictions that start from January and March. According to TCC, RMSE and Skill Score, the predictability is more influenced by lead time than by the effects of topography and/or terrain feature because both HSS and HR varies in different leads over the whole region of South Korea.