고장진단을 위한 영구자식 동기전동기의 권선 단락에 의한 고장모델 연구 및 특성해석

김경화,최동욱,구본관,정인성,Kim, Kyeong-Hwa,Choi, Dong-Uk,Gu, Bon-Gwan,Jung, In-Soung 한국조명전기설비학회 2009 조명·전기설비학회논문지 Vol.23 No.5

고정자 권선의 단락으로 인한 고장을 해석하고 진단 알고리즘의 효과적인 시험 평가를 위해 사용될 수 있는 인버터 구동 영구자석 동기전동기의 고장모델이 제시된다. 기존에 전동기의 해석과 제어에 많이 사용되는 dq 모델은 상전압 모델을 변환한 것으로 전동기 고정자의 권선 단락 시에는 더 이상 3상평형 조건이 성립하지 않기 때문에 인버터 극전압으로부터 전동기 입력 전압을 구하기가 쉽지 않아 고장모델의 해석을 위해서 사용하기 어렵다. 이를 해결하기 위해 전동기 3상 변수와 선전압 관계식을 이용한 전동기의 고장모델이 제안된다. 제안된 고장모델의 타당성을 입증하기 위해 시뮬레이션이 수행되며 내부 고정자의 권선 단락이 가능하도록 제작된 전동기와 DSP TMS320F28335를 이용한 제어 시스템에 의해 동일 고장 조건에서 비교 실험이 수행된다. To analyze influences under faults caused by a stator winding short and to evaluate an effectiveness of a diagnostic algorithm a faulty model for an inverter-driven permanent magnet synchronous motor is presented. Even though the conventional dq motor model obtained through the transformation of phase voltage model is widely used to analyze and control the motor, it can not be used in the analysis of a faulty motor since the 3-phase balanced condition is no longer hold under the fault caused by a stator winding short, and thus, it is very difficult to obtain motor input voltages from the pole voltage of an inverter. To overcome this problem, a faulty model for an inverter-driven permanent magnet synchronous motor is proposed by considering the line voltage of 3-phase variables. The effectiveness of the proposed faulty model is verified through comparative simulations and experiments using DSP TMS320F28335 and motor built to allow a partial short of inter-turn.

Adenovirus에 의해서 발현된 BMP-2가 치주인대세포의 분화에 미치는 영향

김경화,박윤정,이상철,김태일,설양조,이용무,구영,한수부,정종평,류인철,Kim, Kyoung-Hwa,Park, Yoon-Jeong,Lee, Sang-Cheul,Kim, Tae-Il,Seol, Yang-Jo,Lee, Yong-Moo,Ku, Young,Han, Soo-Boo,Chung, Chong-Pyoung,Rhyu, In-Chul 대한치주과학회 2005 Journal of Periodontal & Implant Science Vol.35 No.2

The regeneration of lost periodontal tissue is a major goal of therapy. Periodontal ligament cell(PDL) is a specialized connective tissue that connects cementum and alveolar bone to maintain and support teeth in situ and preserve tissue homoeostasis. Bone morphogenetic proteins(BMPs) have shown much potential in the reconstruction of the periodontum by stimulate new bone and new cementum formation. Limitiations of BMP administration to periodontal lesions is high dose delivery, BMP transient biological activity, and low bioavailability of factors at the wound site. Gene delivery method can be alternative treatment strategy to deliver BMPs to periodontal tissue. The purpose of this study is to investigate efficiency of BMP-2 gene delivery with cell-based therapy using PDL cells. PDL cell were transduced with adenoviruses encoding either BMP-2 or Lac-Z gene. To evaluate osteogenic activity of expressed BMP-2 on PDL cells, we investigated secreted BMP-2, cellular activity, ALPase, produced mineralized nodules. To evaluate collagen scaffold as carrier for transduced cell delivery, we examined morphology and secreted BMP-2 of transducd PDL cells on it. BMP-2 transducd PDL cells produced higher levels of BMP-2, ALPase, mineralized nodules than non transduced cells. Cellular activity of transduced cells was showed similar activity to non transduced cells. Transduce cells attached on collagen scaffold secreted BMP-2 at 7day and was showed similar morphology to non transduced cells. These results demonstrated that transduced PDL cells produced biologically active BMP-2 and collagen scaffold could be carrier of transducd cells.

쥐의 초기 난포 발달에 관여하는 Cell Size Growth 및 CCN Family 유전자에 관한 연구

김경화,박창은,윤세진,이경아,Kim, Kyeoung-Hwa,Park, Chang-Eun,Yoon, Se-Jin,Lee, Kyung-Ah 대한생식의학회 2005 Clinical and Experimental Reproductive Medicine Vol.32 No.3

Objectives: Previously, we sought to compile a list of genes expressed during early folliculogenesis by using cDNA microarray to investigate follicular gene expression and changes during primordialprimary follicle transition and development of secondary follicles (Yoon et al., 2005). Among those genes, a group of genes related to the cell size growth was characterized during the ovarian development in the present study. Methods: We determined ovarian expression pattern of six genes related to the cell size growth (cyr61, emp1, fhl1, socs2, wig1 and wisp1) and extended into CCN family (${\underline{c}}onnective$ tissue growth factor/${\underline{c}}ysteine$-rich 61/${\underline{n}}ephroblastoma$-overexpressed), ctgf, nov, wisp2, wisp3, including cyr61 and wisp1 genes. Expression of mRNA and protein according to the ovarian developmental stage was evaluated by in situ hybridization, and/or semiquantitative reverse transcriptase polymerase chain reaction (RT-PCR), and immunohistochemistry, respectively. Results: Among 6 genes related to the cell size growth, cyr61 and wisp1 mRNA was detected only in oocytes in the postnatal day5 mouse ovaries. cyr61 mRNA expression was limited to the nucleolus of oocytes, while wisp1 was expressed in the cytoplasm and nucleolus of oocytes, except nucleus. cyr61 mRNA expression, however, was found in granulosa cells from secondary follicles. The rest 4 genes in the cell size growth group were detected in oocytes, granulosa and theca cells. Cyr61 and Wisp1 proteins were expressed in the oocyte cytoplasm from primordial follicle stage. Especially, Cyr61 protein was detected in pre-granulosa cells, Wisp1 protein was not. By using RT-PCR, we evaluated and decided that Cyr61 protein is produced by their own mRNA in pre-granulosa cells that was not detected by in situ hybridization. cyr61 and wisp1 genes are happen to be the CCN family members. The other members of CCN family were also studied, but their expression was detected in oocytes, granulose and theca cells. Conclusions: We firstly characterized the ovarian expression of genes related to the cell size growth and CCN family according to the early folliculogenesis. Cyr61 protein expression in the pre-granulosa cells is profound in meaning. Further functional analysis for cyr61 in early folliculogenesis is under investigation.

성견 치주인대세포의 줄기세포 특성 연구

김경화,김수환,설양조,이용무,Kim, Kyoung-Hwa,Kim, Su-Hwan,Seol, Yang-Jo,Lee, Yong-Moo 대한치주과학회 2007 Journal of Periodontal & Implant Science Vol.37 No.3

In spite of the attention given to the study of mesenchymal stem cells derived periodontal ligament (PDL), there is a lack of information about canine PDL cells. In this study, we characterized canine PDL cells to clarify their stem cell properties, including self renewal, proliferate rate, stem cell markers and multipotency. PDL cells were obtained from extracted premolars of canines, following a colony forming assay and proliferation rate of sub-confluent cultures of cells for self-renewal, immunostaining for STRO-1 and CD146/MUC18 and a differentiation assay for multipotency. Canine PDL cells formed single-cells colonies and 25% of the PDL cells displayed positive staining for BrdU. The cells expressed the mesenchymal stem-cell markers, STRO-1 and CD146/MUC18. Under defined culture conditions, the cells differentiated into osteoblasts and adipocytes, but the cells didn't differentiated into chondrocytes. The findings of this study indicated that the canine PDL cells possess crucial stem cells properties, such as self-renewal and multipotency, and express the mesenchymal stem cell markers on their surface. The isolation and characterization of canine PDL cells makes it feasible to pursue preclinical models of periodontal regeneration in canine.

서보 드라이브 성능 향상을 위한 AC 서보 전동기의 적응형 전류 제어

김경화,Kim, Kyeong-Hwa 한국조명전기설비학회 2006 조명·전기설비학회논문지 Vol.20 No.6

서보 드라이브의 성능 향상을 위해 AC 서보 전동기의 MRAC (Model Reference Adaptive Control) 기반 적응 전류 제어 기법이 제시된다. 인버터 구동 전류 제어 기법 중 예측형 전류 제어 기법은 이상적인 과도 응답 및 정상 상태 응답을 주지만, 전동기 파라미터 변화 시 정상상태 응답 성능이 저하된다. 이러한 제한 점을 극복하기 위해 파라미터 변화에 의한 외란이 MRAC 기법에 의해 추정되어 전향 제어에 의해 보상된다. 제안된 방식은 기존의 외란 추정 방식과 달리 관측기 구성을 위한 인버터의 상전압 측정을 필요로 하지 않는다. 제안된 적응 제어 방식의 점근안정성과 효과적으로 서보 드라이브에 적용될 수 있음이 입증된다. 제안된 방식이 DSP TMS320C31을 이용하여 구현되고 유용성이 시뮬레이션과 실험을 통해 입증된다. An MRAC-based adaptive current control scheme of an AC servo motor is presented for the performance improvement of a servo drive. Although the predictive current control is known to give ideal transient and steady-state responses, its steady-state response my be degraded under motor parameter variations. To overcome such a limitation, the disturbances caused by the parameter variations will be estimated by using an MRAC technique and compensated by a feedforward control. The proposed scheme does not require the measurement of the phase voltage unlike the conventional disturbance estimation scheme using observer. The asymptotic stability is proved. The proposed scheme is implemented using DSP TMS320C31 and the effectiveness is verified through the comparative simulations and experiments.

선박/해양플랜트 유지보수 점검용 드론의 기술현황과 과제

김경화,천강우,Kim, Kyunghwa,Chun, Kangwoo 해양환경안전학회 2017 해양환경안전학회지 Vol.23 No.5

군사용으로 먼저 개발되어 온 드론은 요소기술의 급격한 발전을 통해 민간 분야로 확대되면서 최근 다양한 산업분야에 활용되고 있다. 이러한 시대적 흐름에 따라, 조선해양 산업계에서도 유지보수 및 점검용으로 드론의 활용이 유럽을 중심으로 본격화되고 있다. 이와 관련하여, 본 논문에서는 조선해양 분야에 적합한 드론의 기술개발을 위해 선박 및 해양플랜트의 유지보수 점검의 현상태를 진단함으로써 드론 기술개발의 방향성을 제시한다. 즉, 조선해양용 드론이 이미 상용화 된 선진국의 기술력을 살펴보고, 조선해양 산업계에서 드론시대를 대비하여 해결해야 할 기술적 과제들을 소개한다. 또한, 이러한 드론의 시장성장 가능성을 전망함으로써 기술개발의 추진력을 제공하고자 한다. Drones, which were first developed for the military use, have been widely applied in various industrial fields through the rapid development of element technology. Following this trend, the marine industry has started to utilize drones for maintenance and inspection purposes, especially, in Europe. To extend the use of drones in the marine industry, this paper first discusses the necessity of drones for the marine use by presenting problems related to maintenance and inspection works on ships and offshore plants. In addition, the technical levels of advanced countries where drones have been commercialized already in the marine industry are mentioned. Furthermore, technical challenges that must be solved are explained in preparation for a drone era in the marine industry. Lastly, the potential growth of the drone market in the marine industry is considered.

GIS사고 예방진단법의 최근 동향

김경화,Kim, Gyeong-Hwa 한국전기산업진흥회 2000 電氣産業 Vol.11 No.8

사회복지현장실습, 진정한 실습으로 거듭나야 한다

김경화,Kim, Gyeong-Hwa 한국사회복지사협회 2005 Social workers Vol.11 No.-

자매 발화의 분석과 인식에 관한 연구

김경화,Kim KyungHwa 대한음성학회 2001 말소리 Vol.41 No.-

As a pan of voice identification, this study is on the voices from four different groups of sisters. The purpose of this study is to observe and analyze if sister's voices are actually so similar, as many people believe, that it is more difficult to distinguish one from the other than those of unrelated speakers. And it is also aimed to find out what the clues are to decide whether or not the voices are those of the same speaker or of different ones. The result shows that the mean frequencies of $F_3$ and $F_4$ of examined vowels and F0, in some group of sisters, are analyzed similar, In aural test, many listeners took their voices for those of the same speaker.

자율실습에서의 상호동료 교수법 적용경험에 대한 융합적 연구: 핵심기본간호술 투약간호를 중심으로

김경화,임종미,장양민,Kim, Kyung Hwa,Lim, Jong Mi,Jang, Yang Min 한국융합학회 2021 한국융합학회논문지 Vol.12 No.9

본 연구의 목적은 상호동료 교수법을 적용한 핵심기본간호술 자율실습(투약단원을 중심으로)이 간호대학생의 학습에 미치는 영향을 심층적으로 이해하기 위함이다. 연구참여자는 간호학과 4학년 학생 15명이었으며, 심층면담을 통해 자료를 수집하였다. 수집된 자료를 분석한 결과, '학습동기 유발', '자기주도 학습', '성취도 향상', '학습요구 불충족'의 4개의 주제가 도출되었다. 상호동료 교수법을 적용한 핵심기본간호술 자율실습은 참여자들에게 편안한 환경과 자신감 향상으로 학습동기를 유발하고, 주도적인 사전학습 및 학습자의 언어로 학습할 기회를 얻는 긍정적인 경험이 있었다. 하지만, 추가적인 지식확장이 어렵고 충분하지 않은 학습요구로 불안감을 느끼는 경험도 있었다. 이에 상호동료 교수법을 자율실습에 적용할 때, 교수자는 학습자의 학습요구를 충분히 만족시키는 방안을 적용하면 효과적일 것으로 생각된다. The purpose of this study is to understand in-depth the effect of self-directed practice in for core fundamental nursing skills applying reciprocal peer tutoring on the learning of nursing college students. The study participants were 15 students in the 4th grade of the department of nursing, and data were collected through in-depth interviews. The results of analysis resulted in four themes: 'motivation of learning', 'self-directed learning', 'improving achievement', and 'insufficient learning requirements'. The core fundamental nursing skills applying reciprocal peer tutoring has a positive experience of inducing motivation of learning for participants through a comfortable environment and improving self-confidence, and gaining opportunities to lead prior learning and learn in the learner's language. However, there have been experiences where additional knowledge expansion is difficult and feelings of insecurity is felt due to insufficient learning requirements. Therefore, when applying the reciprocal peer tutoring method to self-directed practice, it is considered to be effective if the professor applies a method that can sufficiently satisfy the learner's learning needs.