발전용 대형 가스터빈 연소기의 구조 안정성 평가

이종화(Jonghwa Lee),박성완(Sungwan Park),이동훈(Donghun Lee),이상언(Sangeun Lee) 한국유체기계학회 2016 한국유체기계학회 학술대회 논문집 Vol.2016 No.06

3방 비례제어 조절밸브 개발 및 성능 연구

이종화(Jonghwa Lee),정택수(Taeksu Jung),조종두(Chongdu Cho),김주용(Jooyong Kim) 대한설비공학회 2014 설비공학 논문집 Vol.26 No.5

Korea District heating corp. recently give an attention to combine the district heating and supply pipes as a two pipe system that are in the present system separated with room heating and warm water supply pipe, and the two pipe system is commonly applied for heating service in European countries. In the new two pipe system, only one heat source is supplied to a house and partitioned into room heating and warm water supply by household substation. So the effective distribution of supplied heat source in accordance to user intention is very important. This paper presents the development and performance test of three-way proportional control valve for a combined heat source system in district heating. The proposed valve is controlled to partition heat source into two different directions:hot water distributor for space heating and household substation for warm water supply in response to the pressure drops of tap water caused by the user. The performance investigation is shown within 3% of error compared to the theoretical model of the three-way proportional valve and its controllability is verified.

소고기와 우유에서의 잔류농약 다성분분석을 위한 GC-MS/MS 분석 및 QuEChERS 전처리 방법의 검토

이종화 ( Jonghwa Lee ),오다영 ( Da-young Oh ),박주현 ( Ju Hyeon Park ),민지혜 ( Jihye Min ),임무송 ( Moo-song Lim ),박성국 ( Sung-kug Park ),강인호 ( In-ho Kang ) 한국환경농학회 2021 한국환경농학회 학술대회집 Vol.2021 No.-

Bovine meat and milk are predominant food resources that are consumed by a large portion of the population in the world. Pesticides are commonly used on animal feed and they could be accumulated in animal tissues and other animal-derived foods like milk. To prevent the unnecessary exposure of consumers to pesticides, the determination of pesticide residues in bovine meat and milk is important. However, analyzing pesticide multi-residues in livestock is challenging due to a large amount of lipid and fats as well as the matrix-complexity of animal tissue. Here, we present the initial results of method development for the determination of 127 pesticides using GC-MS/MS. The multiple reaction monitoring transitions were optimized to allow simultaneous quantitation and identification. Sample preparation and clean-up were based on the modified QuEChERS methods. Initial results indicate that extraction with acetonitrile without other acid gave desirable performances in view of the simplicity of the method. Several combinations of the clean-up absorbents and cartridges including C18, PSA, Prime HLB, Captiva EMR-Lipid were compared in terms of recovery rate and repeatability. Further optimization of the sample preparation method and validation of the optimized method is needed for obtaining accurate and reliable data.

지역난방 시스템용 3방 비례제어 조절밸브

이종화(Jonghwa Lee),정택수(Taeksu Jung),조종두(Chongdu Cho),김주용(Jooyong Kim) 대한설비공학회 2013 대한설비공학회 학술발표대회논문집 Vol.2013 No.11

District heating system on an apartment block recently attracts attention to combine hot water supply pipes which are separated with space heating pipe and warm water supply pipe in current system, and this new system is applied for a part of European nations. In combined system, only one heat source is supplied to the house and distributed for space heating and warm water generating by household substation. Therefore, the effective distribution of supplied heat source in accordance with purposes becomes more important. This paper presents a new three-way proportional control valve for mentioned combined heat source system in district heating with experimental result. The valve operates for controls to divides heat source into two different directions : hot water distributor for space heating and household substation for warm water supply in accordance with the pressure drops of tap water induced by the user. This study shows the controllability and performance of the mechanical control three-way proportional valve for common pipe district heating system with result of experiment.

시민의 복지태도와 나눔행동에 관한 연구: 기부와 자원봉사 참여를 중심으로

이종화(Jonghwa Lee),장재혁(Jaehyuck Jang),한민희(Min Hee Han) 연세대학교 사회복지연구소 2019 한국사회복지조사연구 Vol.60 No.-

본 연구의 목적은 시민의 복지태도가 나눔행동에 미치는 영향력을 확인하는 것이다. 이를 위해 서울시와 서울연구원이 서울시 거주 3,019가구를 조사한 2015 서울복지실태조사 데이터를 활용해 시민들이 가진 4가지 복지태도 : 성장과 분배, 선택적 복지와 보편적 복지, 복지지출에 대한 개인과 정부의 책임, 정부복지정책 신뢰수준이 기부와 자원봉사 참여에 미치는 영향을 확인하였다. 분석방 법으로는 두 개의 이항종속변수 사이에 존재할 수 있는 상호의존성을 반영해 효율적인 추정을을 가능하게 해주는 이변량 프로빗 모형을 사용하였다. 연구결과 성장보다 분배를 중요하게 인식할수 록, 정부복지정책에 대한 신뢰가 높을수록 기부에 적극적으로 참여하였고, 복지지출에 대한 정부의 책임을 중요하게 인식할수록 기부에 소극적인 것으로 나타났다. 그리고, 보편적 복지 정책에 대한 중요성 중요하게 인식할수록 자원봉사 참여에 소극적인 것으로 나타났다. 본 연구는 연구의 성과가 부족한 복지에 대한 개인 인식과 나눔 행동 사이의 관계에 대해 실증적인 분석을 하였고, 기부와 자원봉사 행동에 대한 상호의존성을 반영할 수 있는 분석방법을 소개했다는 점에서 의의를 갖는다. The purpose of the study is to identify the influence that the citizen’s attitude of welfare exerts on philanthropic behaviors. Specifically, the study has identified the influences that the citizen’s attitude on the four things, that is, growth and distribution, targeted welfare and universal welfare, the responsibility for welfare expenses, and the trust in the governmental welfare policy, exert on donations and participation in volunteer work. For this purpose, the study used the data from the 2015 Seoul Welfare Survey which was conducted with 3,019 households in Seoul. And for its analytical method, the study employed Bivariate Probit model which enables efficient estimation by reflecting the interdependence that may exist between the two binomial dependent variables. The study showed that people who consider welfare distribution more importantly than economic growth and those who put greater trust in the governmental welfare policy more actively participated in donation, and that those who more strongly believe the governmental responsibility for welfare were more passive in participating in donation, and that those who more strongly believe the importance of universal welfare policy were more passive in participating in volunteer activities. This study has performed an empirical analysis on the relationship between the public perception of welfare and philanthropic behaviors and is significant in that it has introduced a new analytical method that can reflect the interdependence between donation and volunteer participation.

접촉력 추정 정확도 향상을 위한 보행로봇의 마찰 토크 추정

이종화(Jonghwa Lee),강한구(Hangoo Kang),이지홍(Jihong Lee),전봉환(Bong-Huan Jun) 한국해양공학회 2015 韓國海洋工學會誌 Vol.29 No.5

This paper introduces a method to estimate the contact-force of the leg of a walking robot and proposes a solution to a shortcoming of the previous study. This shortcoming was the deteriorating performance when estimating the contact-force whenever the rotation of each joint was reversed. It occurred because the friction-torque of each joint was not considered. In order to solve this problem, a friction-torque model for a robot leg was developed based on repetitive experimentation and used improve the contact-force estimation performance. We verified the performance of the proposed method experimentally.

불규칙한 샘플 영상에 대한 POCS 기반 보간법

이종화(Jonghwa Lee),이철희(Chulhee Lee) 한국방송·미디어공학회 2011 방송공학회논문지 Vol.16 No.4

네트워크 분석을 활용한 ‘문화와 융합’ 트렌드 분석

이종화(Lee Jonghwa),윤지혜(Yun Jihye) 한국문화융합학회 2021 문화와 융합 Vol.43 No.12

데이터의 가치는 새로운 비즈니스 모델을 탄생시키며 디지털 트렌스포메이션을 주도하고 있다. 기업은 고객의 수가 많을수록 더 많은 데이터를 수집할 수 있으며 수집된 데이터 분석을 통해 더 나은 니즈를 충족할 수 있는 제품으로 서비스할 수 있을 것이다. 과거에 발생한 지속적인 데이터를 분석하여 현재 또는 미래에 발생할 사건을 예측하는 과정에서데이터의 가치를 확인할 수 있을 것이다. 본 연구는 ‘문화와 융합’ 학술지를 이용하여 본 학술지의 가치와 연구 트렌드를 확인하고자 한다. 2017년부터 2021년까지 많은 연구자가 집필한 게재 논문의 제목, 키워드, 초록을 년도별로 구분하여 토픽모델링과 네트워크 분석을 통하여연구 트렌드를 분석하였다. 년도별 ‘문화와 융합 학술지 트렌드 및 이슈 키워드 제시와 키워드 영향력 그리고, 키워드간 연결 정도를 제시하여 계보학적 분석 결과로 사료된다. The value of data is driving digital transformation by creating a new business model. Companies are able to collect more data as the number of customers increases and to serve better products through analyzing the collected data. The value of the data can be confirmed in the process of analyzing continuous data that has occurred in the past and predicting events that will occur in the present or future. This study attempts to show the value and research trend of this journal, Culture and Convergence. Research trends from 2017 to 2021 were analyzed through topic modeling and network analysis using the titles, keywords, and abstracts of published papers written by many researchers. This research conducted genealogical analysis on Culture and Convergence by year and presented the journal trends, issue keywords, keyword influence, and the degree of keywords connection.

줄넘기 시 템포가 협응에 미치는 영향

이종화(Lee, Jonghwa),현하경(Hyun, Hakyung),김영호(Kim, Youngho) 한국체육과학회 2022 한국체육과학회지 Vol.31 No.5

The purpose of this study was to compare and analyze the effect of tempo on coordination during jump rope. Thirty healthy adult males participated. The task was to jump rope single under with both feet synchronize with metronome tempo(80, 100, 120, 140, 160 bpm). The joint angles and angular velocities of wrist, elbow, shoulder, hip, knee, and ankle were calculated using data stably performed 5 times consecutively among the data performed 10 times in a row synchronize with metronome tempo. And angle-angle diagram, phase plane portraits, and correlation analysis were analyzed using each joint angle and angular velocity. The results of this study were as follows: First, The angle-angle diagrams show that the joint angles decrease as getting faster the tempo. In the wrist-shoulder and hip-ankle diagrams, coupled coordination was observed as getting faster the tempo. Second, In the phase plane portraits, the angular-angular velocity of all joints showed a convex shape. As getting faster the tempo, the angular velocities of the shoulders, hips, and knees decreased. Third, Elbow-shoulder, hip-knee, knee-ankle, and hip-ankle correlation coefficients were high. It was found that the correlation coefficient of hip-knee and hip-ankle decreased as getting faster the tempo. In conclusion, Wrist, elbow, and ankle joints played a more important role in jumping rope than the shoulder, knee, and hip joints. And, When the tempo of jumping rope was 120 bpm or higher, a stable coordination pattern appeared, but when the jumping rope was slowed at a slow tempo, an unstable coordination pattern was observed.

가상현실 기반 중재가 뇌졸중 환자의 우울과 삶의 질에 미치는 영향에 대한 메타분석

이종화(Lee, Jonghwa),강수진(Kang, Soojin),김영호(Kim, Youngho) 한국체육과학회 2021 한국체육과학회지 Vol.30 No.6

The current study analyzed the effect of virtual reality-based intervention on depression and quality of life in stroke patients. Databases (National Assembly Library, DBpia, RISS, KISS) were searched to extract studies for meta analysis by using the PICOS framework. From this procedure, two dissertations and five journal articles were selected for the literature on the effect on depression, and four dissertations and three journal articles were selected for the literature on the effect on quality of life. The R program(ver.4.0.5) meta analysis package was used to calculate the effect sizes for depression and quality of life. Results using random-effects model indicated that the effect size of depression was -0.82 (95% CI=-1.29, -0.35), which was a large effect size, and also the effect size of quality of life was 1.12 (95% CI=0.56, 1.67), showing a large effect size. The current study concluded that virtual reality-based intervention has positive effect on depression and quality of life in stroke patients.