Changes in the flora in deep caries lesion following a stepwise excavation

Yuran Kim,Sung-Ho Park,Yoo-Seok Shin,Il-Young Jung 대한치과보존학회 2010 Restorative Dentistry & Endodontics Vol.35 No.S2

A Comparison of Control Algorithms for a Doubly Fed Induction Generator in Medium-voltage Wind Power System under Unbalanced Conditions

Yuran Go(고유란),Hyeoncheol Park(박현철),Yaqiong Zhu(주야충),Yongsug Suh(서용석) 전력전자학회 2010 전력전자학술대회 논문집 Vol.2010 No.7

This paper investigates control algorithms for a doubly fed induction generator (DFIG) with back-to-back converter in medium-voltage wind power system under unbalanced grid conditions. Operation of DFIG under unbalanced grid conditions causes several problems such as overcurrent, unbalanced currents, active power pulsation and torque pulsation. Three different control algorithms to compensate for the unbalanced conditions have been investigated with respect to four performance factors; fault ride-through capability, efficiency, harmonic distortions and torque pulsation. The control algorithm having zero amplitude of negative sequence current shows the most cost-effective performance concerning fault ride-through capability and efficiency. The control algorithm for nullifying the oscillating component of the instantaneous active power generates least harmonic distortions. Combination of these two control algorithms depending on the operating requirements presents most optimized performance factors under the generalized unbalanced operating conditions.

A Comparative Study on Control Algorithm for PWM Rectifier of Medium Voltage Drives under Unbalance Input

Yuran Go,Yongsug Suh 전력전자학회 2009 전력전자학술대회 논문집 Vol.2009 No.1

This paper investigates on unbalance compensating control algorithms for the active front-end rectifier employed in high-power motor drive systems. The generic voltage source converter topology of three-level neutral-point clamped rectifier is selected for the comparative study. Three different control laws have been formulated based on the symmetrical components and dq synchronous frames under generalized unbalanced operating conditions. Control algorithms have been investigated with respect to major design factors in large drive systems; fault ride-through capability, efficiency, and harmonic distortions. The control law having zero amplitude of negative sequence input current shows the most optimized and cost-effective performance regarding fault ride-through capability and efficiency aspects. The control algorithm nullifying the oscillating components of the instantaneous active power generates least harmonic distortions. Combination of these two control algorithms depending on the system requirement and operating mode provides improved performance factors of fault ride-through capability, efficiency, and low harmonic distortions under the generalized unbalanced operating conditions.

A Preliminary Study of Designing Ubiquitous Applications for Language Education

Yuran Kim 한양대학교 교육공학연구소 2010 학습과학연구 Vol.4 No.1

This study defines ubiquitous computing as a powerful tool for language education. In particular, mobile devices have a huge possibility to catch learner’s attention. The study is to 1) analyze popular language learning applications using ubiquitous technology 2) draw some principles for designing new applications. Through literature review, simple evaluation scale was developed to analyze three most popular mobile device language applications. There are sufficiently few items for rapid evaluation, yet enough items to catch key characteristics. The general pros and cons were selected through the result of analyzing. This paper holds potential for designing ubiquitous application for language education. Further use of the result could lead to a better form of language learning application.

Effective Environmental Education through Ubiquitous Computing Technology

Yuran Kim,Seah Yu 한양대학교 교육공학연구소 2009 학습과학연구 Vol.3 No.1

The purpose of this study is to propose future educational scenarios for environmental education in a ubiquitous society. A review of cases in the literature using technologies such as mobile devices, virtual reality and sensorbased systems is presented. This paper also describes some traits of ubiquitous society centered an individualization, just-in-time learning, networking and simulation for environmental education.

Sulfation diffusion model for SO2 capture on the T-T sorbent at moderate temperatures

Yuran Li,Changfu You,Haiying Qi,Lizhai Yang 한국화학공학회 2009 Korean Journal of Chemical Engineering Vol.26 No.4

A sulfation model was developed for dry flue gas desulfurization (FGD) at moderate temperatures to describe the reaction characteristics of the T-T sorbent clusters and the fine CaO particles that fall off the sorbent grains in a circulating fluidized bed (CFB) reactor. The cluster model describes the calcium conversion and reaction rate for various size sorbent clusters. The sulfation reaction is first order with respect to the SO2 concentration above 973 K. The calcium conversion and reaction rate for the CaO particles were obtained by extrapolation. In the model for CaO particle, the reaction rate is linearly related to the calcium conversion and the SO2 concentration in the rapid reaction stage and linearly related only with the calcium conversion after the product layer forms. The sulfation model accurately describes the sulfation of the T-T sorbent flowing through a CFB reactor.

Using structural intensity approach to characterize vibro-acoustic behavior of the cylindrical shell structure

Wang, Yuran,Huang, Rong,Liu, Zishun Techno-Press 2018 Coupled systems mechanics Vol.7 No.3

In this paper, the vibro-acoustic behaviors of vibrational cylindrical shells are investigated by using structural intensity approach. The reducing interior noise method for vibrating cylindrical shells is proposed by altering and redistributing the structural intensity through changing the damping property of the structure. The concept of proposed novel method is based on the properties of structural intensity distribution on cylindrical shells under different load and damping conditions, which can reflects power flow in the structures. In the study, the modal formulas of structural intensity are developed for the steady state vibration of cylindrical shell structures. The detailed formulas of structural intensity are derived by substituting modal quantities, in which the effect of main parameters such as weight coefficients and distribution functions on structure intensity are analyzed and discussed. Numerical simulations are first carried out based on the structural intensity analytical solutions of modal formulas. Through simulating the coupling vibration and acoustical radiation problems of cylindrical shell, the relationship between vibro-acoustic and structural intensity distribution is derived. We find that for cylindrical shell, by properly arranging damping conditions, the structural intensity can be efficiently changed and further the noise property can be improved. The proposed methodology has important implications and potential applications in the vibration and noise control of fuselage structure.

CHAID분석을 이용한 서울시 지하철 역세권 지가 영향모형 개발

최유란(Yuran Choi),김태호(Tae-Ho Kim),박정수(Jung-Soo Park) 한국철도학회 2008 한국철도학회논문집 Vol.11 No.5

조현병 환자의 내재화된 낙인과 관련된 요인

정유란(Yuran Jeong),유태영(Taeyoung Yoo),이주연(Ju-Yeon Lee),김선영(Seon-Young Kim),김재민(Jae-Min Kim),윤진상(Jin-Sang Yoon),김성완(Sung-Wan Kim) 대한생물치료정신의학회 2017 생물치료정신의학 Vol.23 No.2

Objectives:Patients with schizophrenia have high levels of self-perceived stigma, which frequently hinders successful treatment. The aim of this study was to investigate the factors related with internalized stigma in patients with schizophrenia. Methods:A total of 123 patients with schizophrenia according to Diagnostic and Statistical Manual of Mental disorders 5th edition(DSM-5) criteria were enrolled. Sociodemographic and clinical variables including previous suicidal attempt history were assessed. Self-perceived stigma was assessed using Korean version of Internalized Stigma of Mental Illness Scale(K-ISMI). Clinical characteristics and psychopathology were measured using the Positive and Negative Syndrome Scale(PANSS), Beck Depression Inventory(BDI), Beck Hopelessness Scale-7(BHS-7), Rosenberg Self Esteem Scale(R-SES), and EuroQol-5 dimensions visual analog scale(EQ5D-VAS). Results:The K-ISMI total scores had significantly negative correlations with scores on the R-SES and EQ-VAS, and significantly positive correlations with scores on the BDI, BHS-7, and PANSS negative and general psychopathology subscales after controlling age and duration of illness. Patients with previous suicidal attempt history showed significantly higher scores on the K-ISMI scores. Conclusion:Internalized stigma of patients with schizophrenia was associated with low self-esteem, poor quality of life, history of suicidal attempt and higher level of depression, hopelessness, and negative symptoms. Clinicians should carefully evaluate and manage self-perceived stigma of patients with schizophrenia.

가치명료화 이론 보완을 위한 ‘자기성찰’발문 적용 방안

김유란(yuran Kim) 한국열린교육학회 2023 열린교육연구 Vol.31 No.3

본 연구는 가치명료화 이론의 문제점을 보완하고, 사회관계적인 측면을 고려할 수 있는 가치교육의 방법을 모색하기 위해 자기성찰 발문을 가치명료화 이론의 가치화 과정에 적용하는 방안을 제시하였다. 가치명료화 이론은 학습자가 자유롭게 가치관을 형성할 수 있도록 한다는 장점이 있지만, 학습자 개인의 가치 선택을 지나치게 강조하다 보니 자기중심적인 가치판단을 할 수 있다는 한계가 있다. 인간은 세계 내 존재로 타인과 관계를 맺으며 살고 있다. 다양한 가치 갈등 상황에서 자신의 관점만을 고려한다면 사회 속에서 타인과 더불어 살아가는 인격체로서 성장하는 데 제한적일 수 있다. 본 연구는 이러한 가치명료화 이론의 단점을 보완하기 위해 자기에 대한 올바른 자각을 바탕으로 타인을 이해하는 자기성찰 개념에 주목하고 자기인식, 불일치, 통합을 통해 이루어지는 자기성찰을 수업 상황에 활용할 수 있는 방안을 탐구하였다. 이에, 자기성찰 내용을 발문의 형태로 구성하고 이를 가치명료화 이론의 가치화 과정의 발문에 적용하였다. 이러한 작업은 토의·토론, 글쓰기 등 다양한 교수학습 방법에 활용됨으로써 교육적 효과성을 담보할 수 있을 것으로 기대된다. This study proposed a method of applying self-reflection questions to the process of valuing the value clarification theory in order to supplement the problems of the value clarification theory and to seek a method of value education that can consider the social relational aspect. The value clarification theory has the advantage of allowing learners to freely form values, but it has limitations in that they can make self-centered value judgments because it overemphasizes individual learners' value choices. Human beings engage in relationships with others as beings in the world. If one only consider their own point of view in various value conflict situations, one may be limited in growing into a person who lives together with others in society. In order to compensate for these shortcomings, this study focused on the concept of self-reflection to understand others based on a correct self-awareness and explored ways to utilize self-reflection through self-awareness, discordance, and integration in class situations. Therefore, the content of self-reflection was composed in the form of an epilogue and applied to the process of valuing the theory of value clarification. It is expected that this work will ensure educational effectiveness by being used in various teaching and learning methods such as discussion, discussion, and writing.