한국 성인 나눔행동의 잠재전이분석(LTA)을 통한 정신건강의 종단적 변화 : 누가 기부와 자원봉사에 참여하는가?

권재기(Kwon, Jae Ki) 한국정신건강사회복지학회 2021 정신보건과 사회사업 Vol.49 No.3

이 연구는 누가 기부와 자원봉사에 참여하는지에 대한 호기심에서 출발하였다. 최근까지 논의된 나눔행동(기부, 자원봉사)의 관계와 지속성을 중요하게 고려하였고, 나눔행동의 전이에 따른 집단을 탐색하고, 이들의 인구사회학적 특성과 정신건강의 변화를 살펴보고자 하였다. 이를 위해 한국복지패널조사의 14차년(2006년~2019년) 데이터를 활용하였고, 총16,736명을 대상으로 하였다. 연구결과, 잠재전이분석을 통하여 나눔행동 지속 집단(3.2%), 나눔행동 무경험 집단(69.2%), 자원봉사 지속 집단(0.3%) 등과 같은 총 10가지 패턴의 집단유형이 도출되었다. 인구사회학적 특성으로는 지속적인 나눔 집단의 경우, 수도권에 거주하고, 최종학력이 높고, 배우자가 있고, 종교를 가지고 있으면서 정규직이 많고, 직업은 관리직, 전문직과 사무직이 많고, 소득이 높은 것으로 나타났다. 마지막으로 전이된 집단 유형 중에서 나눔행동 지속 집단은 우울이 가장 낮고, 건강만족도와 행복감의 초기치가 높고, 지속적으로 높은 상태를 유지하는 것으로 나타났고, 비교하여 나눔행동 무경험 집단은 건강만족도와 행복감의 타집단보다 낮고, 우울은 타집단보다 가장 높은 상태를 유지하는 것으로 나타났다. 이 연구를 통하여 나눔행동이 지속될 때 정신건강은 어떠한 영향을 미치는지를 종단적으로 확인한 점에서 의의가 있다. This study started out of curiosity about who participates in donations and volunteering. The relationship and continuity of sharing behaviors(donation, volunteering) discussed until recently were considered as important, and groups according to the transfer of sharing behaviors were explored, and their demographic characteristics and changes in mental health were investigated. For this purpose, data from the 14th year (2006-2019) of the Korea Welfare Panel Survey were used, and a total of 16,736 people were targeted. As a result of the study, a total of 10 group types were derived, such as the group that continued sharing behavior (3.2%), the group that had no experience in sharing behavior (69.2%), and the group that continued volunteering (0.3%) through the latent transition analysis. As for the socio-demographic characteristics, in the case of the continuous sharing group, it was found that they live in the metropolitan area, have a high final education, have a spouse, and have a religion, but have a lot of regular workers, and their occupations are managerial, professional and clerical, and high income. Lastly, among the group types that were transferred, the group that continued sharing behavior had the lowest depression, high initial values of health satisfaction and happiness, and maintained a consistently high state. It was found that it was lower than the group, and the depression maintained the highest state than other groups. Through this study, it is significant in that it longitudinally confirmed the effect on mental health when sharing behavior continues.

기독 청소년의 자살위험 프로파일 탐색 및 예측

권재기(Jae-ki Kwon),오태균(Taekyun Oh) 한국기독교교육정보학회 2020 기독교교육정보 Vol.0 No.67

본 연구는 기독 청소년의 자살 프로파일을 탐색·분류하여 동질 한 특성을 가진 이들의 개인 특성, 가정 특성, 그리고 자살 특성의 차이를 살펴보았다. 이를 통하여 기독 청소년의 자살에 영향을 미치고 위험도를 높이는 요인들을 탐색하고, 조사함으로 청소년 자살을 예측하고 예방하기 위한 기초자료를 확보하고 제공함으로 한국사회와 교회의 미래인 청소년들의 심리 내외적인 건강증진과 신앙지도를 위한 도구를 제공함에 그 목적이 있다. 기독 청소년의 자살위험 프로파일을 탐색한 결과, 보통형(42.1%), 자살 위험형(27.2%), 건강형(30.7%)이 도출되었다. 둘째, 분류된 세 집단별 개인 및 가정환경특성의 차이를 분석한 결과, 건강형이 신앙 년 수가 높고, 성경공부, 기도, 찬양을 많이 하고, 학업성적이 우수하고, 친한 친구의 수가 많고, 가정환경에서 부와 모의 종교가 기독교이고, 부모의 신앙 년수가 높은 가정이 많았고, 가정예배를 많이 하고, 부모와의 의사소통도 원활한 것으로 나타났다. 특히 신앙활동과 부모의 신앙활동이 건강형이 되기 위한 중요요건으로 나타났다. 반대로 자살위험형은 건강형과 보통형 보다 신앙활동(신앙년수, 성경공부, 기도, 찬양)이 가장 낮은 것으로 나타났다. 셋째, 도출된 자살위험 프로파일에 따른 세 집단의 자살특성을 예측한 결과, 자살사이트를 방문한 경험이 있을수록 자살 위험형을 예측하였다. 본 연구의 결과를 토대로 교회 안에서, 그리고 기독 가정 안에서 기독 청소년의 자살위험을 막기 위한 예방과 개입 방안을 마련할 필요가 있다. This study explored and categorized the suicide profiles of Christian adolescents to examine the differences in personal characteristics, family characteristics, and suicide characteristics of those with homogeneous characteristics. Through this, by exploring and investigating factors that affect suicide of Christian youth and increasing the risk of youth suicide, we secure and provide basic data for predicting and preventing youth suicide. Its purpose is to provide tools for guidance. As a result of searching the suicide risk profile of Christian adolescents, normal type(42.1%), suicide risk type(27.2%), and healthy type(30.7%) were derived. Second, as a result of analyzing the differences in personal and family environment characteristics by the three classified groups, the healthy type has a high number of years of faith, a lot of Bible study, prayer, and praise, excellent academic performance, and a large number of close friends. In the environment, it was found that the religion of the father and mother was Christianity, and there were many families with a high number of parents, worshiping at home, and communication with parents was smooth. In particular, faith activities and parental faith activities were found to be important requirements for becoming a healthy type. On the contrary, the suicide risk type showed the lowest religious activity (years of faith, Bible study, prayer, praise) than the healthy type and the normal type. Third, as a result of predicting the suicide characteristics of the three groups according to the derived suicide risk profile, the more experienced they visited the suicide site, the more the suicide risk type was predicted. Based on the results of this study, it is necessary to prepare prevention and intervention measures to prevent suicide risk of Christian youth in churches and in Christian families.

티타늄 합금(Ti-6Al-4V)의 조직변화에 따른 피로수명 평가

권재도(Jaedo Kwon),최성종(Sungjong Choi),배용탁(Yongtak Bae) 한국자동차공학회 2004 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-

The specific gravity of titanium alloy is 4.5 which is lighter than steel, however, its specific strength, heat and corrosion resistance are superior to steel. Therefore, it is used in spaceships, medicines, and so on. Ti-6Al-4V alloy is a kind of α+β phase titanium alloy, and mechanical properties are changed by alloy elements, shapes and distributions of microstructures. In this paper, the effect of microstructure on mechanical behavior for Ti-6Al-4V alloy was studied. Three different kinds of specimens are prepared under different heat treatments (rolled plate, 980℃, 1050℃) in order to produce different microstructures. Various kinds of mechanical tests such as hardness, tensile, fatigue and fretting fatigue tests are performed for evaluation of mechanical properties with the changes of microstructures. Through these tests, the following conclusions are observed: I) Microstructures are observed as equiaxed, bimodal and lamellar microstructures respectively. 2) Impact absorbed energy is superior for the bimodal microstructure, and the hardness and tensile strength are superior for the lamellar microstructure. 3) The fatigue endurance of lamellar structure shows higher value than that of the equiaxed and bimodal structures. 4) Fractal dimension depend on maximum stress and heat treatment temperature.

인공해수 환경에서의 표면부식 및 전기방식이 X80 강재의 S-N 피로거동에 미치는 영향

권재기 ( Jae Ki Kwon ),안두홍 ( Doo Hong Ahn ),정대호 ( Dae Ho Jeong ),김영주 ( Young Ju Kim ),우남섭 ( Nam Sub Woo ),김상식 ( Sang Shik Kim ) 대한금속재료학회(구 대한금속학회) 2014 대한금속·재료학회지 Vol.52 No.10

Abstract: The effects of pre-corrosion and applied potentials in artificial seawater on the S-N fatigue behavior of X80 steel were examined. The X80 specimens were pre-corroded in a FeCl3 solution for varying immersion times ranging from 0 to 96 h and subsequently S-N fatigued in air. It was found that the resistance to S-N fatigue decreased abruptly with 1 h immersion, while it became saturated with a further increase in immersion time. The trend observed in this study was relatively well explained by the stress concentration effect from the presence of corrosion damage on the surface. The in-situ S-N fatigue tests were also conducted on X80 steel in artificial seawater under applied potentials of .600, .850 and .1,050 mV (SCE). The fractographic and micrographic analyses were conducted on the fatigue specimens to identify the optimum cathodic protection conditions.

304 스테인리스강 주조재의 저온 S-N 피로거동 예측

권재기 ( Jae Ki Kwon ),이현정 ( Hyun Jung Lee ),김영주 ( Young Ju Kim ),김상식 ( Sang Shik Kim ) 대한금속재료학회(구 대한금속학회) 2011 대한금속·재료학회지 Vol.49 No.10

S-N fatigue behavior of cast 304 stainless steel was studied at 25, -50 and -196℃ and at a stress ratio of -1 in uniaxial and bending loading condition. It was found that the resistance to S-N fatigue was greatly improved with decreasing testing temperature. The normalized S-N fatigue curves by tensile strength at three different testing temperatures matched each other, suggesting that tensile strength determines the S-N fatigue resistance of cast 304 stainless steel at low temperatures. The effectsof different loading on the resistance to S-N fatigue of cast 304 stainless steel were quantified. The S-N fatigue curves at 25, -50 and -196℃ were described by using Basquin`s law the relationship between the S-N fatigue curve and the testing temperature was obtained by using a simple regression method.

전단변형률 제어하에서 열화를 고려한 2상 스테인리스강의 저주기 피로특성 평가

권재도(Jae Do Kwon),박중철(Joong Cheul Park) 대한기계학회 2002 대한기계학회 춘추학술대회 Vol.2002 No.5

Monotonic torsional and pure torsional low cycle fatigue test with artificially degradation were<br/> performed on duplex stainless steel(CF8M). CF8M is used in pipes and valves in nuclear reactor<br/> coolant system. The method of artificially degraded is used thermal aging for 3600 hrs at 430℃ and<br/> specimens is thin-walled tubular. In order to inhibition, crack nucleation and growth of specimen inside<br/> was worked electrolytic-polishing. The mechanical properties of monotonic and low cycle fatigue are<br/> increased by effect of material degradation and transition fatigue life is decreased about 60%.

자동차용 서스펜션 섬유강화 복합재 코일 스프링의 압축특성 및 손상평가

권재기 ( Jae-ki Kwon ),전정일 ( Jung-il Jeon ),신정규 ( Jung-kyu Shin ) 한국복합재료학회 2022 Composites research Vol.35 No.6

본 연구에서는 브레이딩 공법으로 자동차용 섬유강화 복합재 코일 스프링을 제작했으며, 안전성 확인을 위해 압축시험 후 손상평가를 진행하였다. 하중-변위 거동의 분석을 통해 스프링의 강성이 규격에 부합하는지 평가했다. 또한 복합재료의 기계적 특성에 대한 기준을 명확하게 파악하기 위해 기공의 분포 및 함침율을 분석하였다. 시험이 완료된 스프링은 육안검사를 진행하여 손상부를 확인했으며, SEM을 이용하여 스프링의 균열 및 파손 인접부에서 채취한 횡단면 시료의 균열 발생 및 진전부 관찰을 통해 파괴모드를 분석하였다. In this study, fiber-reinforced composite coil springs for automobiles were manufactured using the braiding method, and mechanical tests and damage evaluation were performed to confirm their safety. Through the analysis of the load-displacement behavior, the stiffness of the springs was evaluated to meet the specifications. In addition, the distribution of voids and the impregnation rate on the spring wire section were analyzed to clearly understand the criteria for the mechanical properties of the composite material. Moreover, the tested springs were visually inspected to confirm the damaged parts, and the failure mode was analyzed by observing crack initiation and propagation behavior of cross-sectional samples taken from the crack and failure adjacent areas of springs using SEM.

SiCp / Aℓ 6061 복합재료의 피로균열진전특성에 관한 통계학적 해석

권재도(J. D. Kwon),문윤배(Y. B. Moon),안정주(J. J. Ahn) 한국자동차공학회 1996 한국 자동차공학회논문집 Vol.4 No.4

The silicon carbide particles reinforced aluminium 6061(SiCp/ Aℓ) composites are generally known have wild range of applications from automobiles to airospaces. But, by the results of existing study for SiCp/ Aℓ composites, there are reports that the fatigue life of SiCp/ Aℓ composites has improved than AR matrixes and has not improved then Aℓ matrixes.<br/> Consequently, in order to perform the reliable life prediction for SiCp/ Aℓ, the properties of probability distribution of fatigue crack initiation life & fracture life, crack growth length in constant number of cycles, crack growth rate in constant stress intensity factor range and m & C value in Paris's fatigue crack growth law and the estimation of statistical parameters have been evaluated by the statistics method.<br/>

SiC 입자 보강 AI 복합재료의 통계학적 피로균열진전거동에 관한 연구

권재도(Jae-Do Kwon),문윤배(Yun-bae Moon),안정주(Jung-Ju Ahn) 한국자동차공학회 1995 한국자동차공학회 춘 추계 학술대회 논문집 Vol.1995 No.11_1

The silicon carbide particles reinforced aluminium 6061(SiCp/ AI composites are generally known have wild range of applications from automobiles to airospaces. But. by the results of existing study for SiCp/AI composites. there are reports that the fatigue life of SiCp/AI composites has improved than Al matrixes and res not improved then AI matrixes.<br/> Consequently. in order to perform the reliable life prediction for SiCp/Al. the properties of probability distribution of fatigue crack initiation life & fracture life. crack growth length in regular number of cycle, crack growth rate in regular stress intensity factor range and m & C value in Paris's fatigue crack growth law and the estimation of statistical parameters have been evaluated by the statistics method

학령후기 학교적응 프로파일과 관련된 개인,가정환경 변인의 단기 종단적 분석: 잠재프로파일분석을 이용하여

권재기 ( Jae Ki Kwon ),정미경 ( Mi Kyung Chung ) 한국아동교육학회 2012 아동교육 Vol.21 No.3

본 연구는 학령후기 아동의 특성에 따라 동일한 학교적응의 하위 유형(프로파일)이 존재하는지를 확인하고, 이러한 하위 유형을 예측하는 아동의 개인적 특성과 가정환경 요인을 검증하는 단기 종단연구를 실시하였다. 총 4,726명의 아동을 대상으로 학교적응 프로파일을 탐색하기 위해 네 가지 지표(학업성취도, 학교만족도, 교사관계, 교우관계)를 모형에 투입하여 잠재프로파일분석(LPA; Latent Profile Analysis)을 실시하였다. 그 결과, 학교적응 하위 유형으로 ``적응집단(n=3,450, 73.0%)``, ``교우관계 부적응 집단(n=477, 10.1%)``, ``학업부진 집단(n=235, 5.0%``, ``학교 및 교사관계 불만 집단(n=564, 11.9%)``이 확인되었다. 이들 학교적응 프로파일의 집단은 네 가지 지표에 따라 유의미한 차이가 나타났다. 다음으로 아동 개인특성 및 가정환경 특성을 토대로 학교적응 프로파일에 나타난 네 집단을 예측하는 요인을 살펴본 결과, 개인적 특성에서 적응집단은 수업태도와 학업성취도면이 다른 집단에 비하여 안정적임을 알 수 있었다. 가정환경 특성에서는 아동 개인과 부모의 생각 차이가 크다는 것을 발견할 수 있었다. 본 연구 결과는 학교적응을 파악할 때, 아동 개인을 둘러싸고 있는 다양한 생태 체계적 변인을 중심으로 다양한 각도에서 학교적응 프로파일을 도출하는 접근이 유용할 것임을 시사한다. 이러한 결과를 바탕으로 본 연구의 의의 및 기대효과에 대한 제언이 논의되었다. The purpose of this study is to research school adaptation profile at later school years with LPA (Latent Profile Analysis), and furthermore seek the short-term longitudinal study of variables predicting characteristics of different groups in school adaption profile. Especially, four indicators such as academic achievement, school satisfaction, teacher relationships, and schoolmate relationships are applied to the research of school adaptation profile. The conclusion of this study is summarized as follows. First, 4 groups such as ``adaptation group``, ``maladaptation group of schoolmate relationships``, ``group of low academic achievement``, ``dissatisfaction group of school and teacher relationships`` are verified by LPA researching school adaptation profile at later school years. Secondly, the analysis of personal variables regarding the characteristics of 4 groups in school adaptation profile shows us that the adaptation group is more stable than other groups in terms of variables such as attitude in class and academic achievement. Thirdly, the analysis of home environmental variables brought us the conclusion that students have different ways of thinking from their parents`. Finally, the importance and expected effect of this study are discussed based on those conclusions.