• 제목/요약/키워드: 서울시립대학교

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주기 하중을 받는 3-자유절점 공간 트러스의 동적 불안정 현상과 주파수 특성 (Dynamic Snapping and Frequency Characteristics of 3-Free-Nodes Spatial Truss Under the Periodic Loads)

  • 손수덕;황경주
    • 한국공간구조학회논문집
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    • 제20권4호
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    • pp.149-158
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    • 2020
  • The governing equation for a dome-type shallow spatial truss subjected to a transverse load is expressed in the form of the Duffing equation, and it can be derived by considering geometrical non-linearity. When this model under constant load exceeds the critical level, unstable behavior is appeared. This phenomenon changes sensitively as the number of free-nodes increases or depends on the imperfection of the system. When the load is a periodic function, more complex behavior and low critical levels can be expected. Thus, the dynamic unstable behavior and the change in the critical point of the 3-free-nodes space truss system were analyzed in this work. The 4-th order Runge-Kutta method was used in the system analysis, while the change in the frequency domain was analyzed through FFT. The sinusoidal wave and the beating wave were utilized as the periodic load function. This unstable situation was observed by the case when all nodes had same load vector as well as by the case that the load vector had slight difference. The results showed the critical buckling level of the periodic load was lower than that of the constant load. The value is greatly influenced by the period of the load, while a lower critical point was observed when it was closer to the natural frequency in the case of a linear system. The beating wave, which is attributed to the interference of the two frequencies, exhibits slightly more behavior than the sinusoidal wave. And the changing of critical level could be observed even with slight changes in the load vector.

고유수용성 저항운동이 사회복지시설 이용 여성 노인의 근지구력, 동적 평형성 및 보행능력에 미치는 영향 (Effects of proprioceptive exercise on muscle endurance strength, dynamic balance and gait ability of elderly women in social welfare facility)

  • 오유성;박우영
    • 한국응용과학기술학회지
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    • 제37권6호
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    • pp.1669-1677
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    • 2020
  • 이 연구의 목적은 14주 고유수용성 저항운동이 사회복지시설 이용 여성 노인의 근지구력, 동적 평형성 및 보행능력에 미치는 영향이었다. 이 연구에 참여한 대상자는 평균연령이 70세 전후의 30의 여성 노인을 운동집단 15명과 통제집단 15명으로 구성하였다. 대상자들은 운동프로그램 전과 후에 근지구력(30초 의자 앉았다 일어서기), 동적 평형성(3m 왕복 걷기)과 보행능력(10m 걷기, 400m 걷기)을 검사하였다. 운동집단은 주 3회 60분간 스위스 볼을 이용한 고유수용성 저항운동을 하였다. 연구 결과 하체 근지구력에서는 유의한 개선이 있었고, 동적 평형성을 평가하는 3m 왕복 걷기에서도 유의한 개선이 있었다. 보행능력인 10m 걷기와 400m 걷기에서도 유의한 개선이 있었다. 결론적으로 고유수용성 저항운동에 의한 동적평형성과 보행능력의 개선은 여성 노인의 낙상 관련 가능성을 감소시킬 것이다.

고종대 경복궁 중건 시 영건일기에 나타난 목재 조달 고찰 (A Study on the Wooden Procurement in the Diary of Yeonggun during the Construction of Gyeongbokgung Palace in King Gojong's reign)

  • 김버들;조정식
    • 건축역사연구
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    • 제29권6호
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    • pp.101-112
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    • 2020
  • This study focuses on the construction of Gyeongbokgung Palace in the second year of King Gojong's reign, which has been spotlighted for political and economic history. The author analyzed the contents of wood procurement with the Yeonggeon Diary, which records each day of construction site. The results are as follows: First, the 2nd year of King Gojong's reign, Yeonggeon of Gyeongbokgung Palace, was a new building that reflected the old system and 270 years of changed environment on the existing site. Despite the poor economic conditions, it began with years of effort and voluntary volunteer work and dedication. Second, the priority of timber transport was recruiting people in the whole process and the supply and demand of transportation tools. Carrying lumber from the mountains to the riverside and floating it at the right time were all a matter of manpower. Soldiers and carts were used to carry timber that arrived in Hangang River to the construction site. The cart was a consumable product, so it was necessary to continuously use the wood to make cart at the site. Third, fire and flood were the biggest obstacles to the Yeonggeon schedule of Gyeongbokgung Palace. Especially the fire was fatal. It was difficult to extinguish the fire in temporary structure, where was the storage for wood to construct. These disasters greatly affected the construction cost and construction period. Wood procurements of Gyeongbokgung Palace were based on public offerings. At the same time, recycled materials from other palace wood and nearby houses, nationwide buying of private mountain wood, the logging of royal tombs and some of the buildings of Gyeonghui Palace and Changgyeong Palace were relocated.

코로나19로 인한 식품 소비행태 변화분석: MZ세대를 중심으로 (Analysis of Food Consumption Behavior due to COVID-19: Focusing on MZ Generation)

  • 이홍승;김준환
    • 디지털융복합연구
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    • 제19권3호
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    • pp.47-54
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    • 2021
  • 본 연구는 소비자들의 구매패턴이 1인 가구와 맞벌이 부부의 증가 등과 같은 인구통계학적 변화로 이미 변경되고 있는 상황에서, 최근의 코로나19 사태로 인해 그 변화가 가속화될 것이라고 전망된다. 이를 위해 전문조사업체인 닐슨코리아의 패널 500명을 대상으로 온라인 설문조사를 수행한 분석결과를 본 연구에 활용하였다. 특히 소비자를 2개의 세대 그룹(Z세대 vs. 밀레니얼세대)으로 나누어 코로나19로 인해 바뀐 소비활동 변화와 식품구매 행태를 분석하여 제시하였다. 그 결과, 기존 온라인 유통이 강화되어가고 있던 추세가 코로나19로 인해 그 영향이 증폭되었다. 이러한 변화는 세대별로 코로나19 우려 정도의 차이에 따라 소비행동도 다르게 나타났다. 본 연구결과를 토대로 가속화하고 있는 '언택트' 중심으로 소비자들의 행동변화를 새로운 기회로 전환시키는데 있어 관련된 이론적 의의와 실무적으로는 식품업계의 대응전략에 대한 관리적 시사점을 제공할 것이다.

요양보호사의 직무환경이 조직몰입에 미치는 영향: 직무만족의 매개효과 검증 (The Effect of Care-workers Work Environment on Organizational Commitment: The Mediation Effects of Job Satisfaction)

  • 홍서준;김진우
    • 산업융합연구
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    • 제20권7호
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    • pp.107-113
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    • 2022
  • 본 연구는 요양보호사의 직무환경이 조직몰입에 미치는 영향을 파악하고 이를 토대로 직무만족의 매개효과를 검증하는 것을 목적으로 한다. 자료수집은 경기지역 노인요양시설을 중심으로 요양보호사 300명을 대상으로 설문조사를 하였고, 회수되지 않은 설문지와 이상치를 제거하고 최종 267명을 연구대상으로 선정하였다. 자료분석은 SPSS WIN 23.0, PROCESS Macro V3.5를 통해 결과를 도출하였고, 직무만족의 매개효과 검증을 위해 Hayes(2013)의 Macro Model Number 4를 적용하였다. 분석결과, 요양보호사의 직무환경이 조직몰입에 미치는 영향에서 직무만족 변인의 부분매개효과를 확인하였다. 분석결과를 토대로 요양보호사의 직무환경 개선과 직무만족 증가를 위한 실천적·정책적 제언과 본 연구의 한계를 극복하기 위해 후속 연구를 제안했다.

소설 『미망』 속 개성 한옥 고찰 (A study on the Gae-sung Han-ok of in the 『Mi-mang』 of novel)

  • 김버들;조정식
    • 건축역사연구
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    • 제31권3호
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    • pp.41-52
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    • 2022
  • This study explains the han-ok. in Gae-sung, which was antique and traditional city. In view of the fact that these were located in Gae-sung in North Korea hence direct investigate is not possible. Since there was no comprehensive study of Gaeseong han-ok, we have no choice but to rely on fragmentary records and memory of Gaeseong people. In accordance from the Japanese colonial era's surveys and sketches as well as how they were illustrated in the novel. Hark back to the peoples' thought of the han-ok years when they ran the survey in 1920s, the results were as follows: First, there are many houses so various classes in Mi-Mang. Jeon Cheo-man's house was a representative example of a rich family in Gae-sung, Jeon Je-seong(Jeon's 2nd son)'s house was located in Si-jeon(government licensed-markets) near by the South gate. In particular, Jeon Yi-seong(Jeon's 3rd son)'s house was in rural areas. He managed on immense ginseng field and worker's houses. Hae-ju's house was a small house off the track. Second, the outer house is low and the main house is high and neat. Lastly, it was confirmed that it corresponded to sketches recorded by architects, such as neat housekeeping, long stones used for various purposes, invisible flat gates, the appearance of old and old houses and the composition of each room.

광폭 플랜지 PSC 거더 단부 프리캐스트 블록을 활용한 반일체식교대교량의 구조성능 평가 (Structural Performance Evaluation on Ended Block of Wide Flange PSC Girder for the Semi-Integral Bridges)

  • 가훈;최진우;김영호;박종면
    • 대한토목학회논문집
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    • 제42권1호
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    • pp.1-9
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    • 2022
  • 반일체식교대교량은 일체식 교대교량의 한 형식이다. 이 교량은 상부구조에서 신축조인트를 제거한 것으로 완전일체식 교대교량이 적용하지 못한 상황에 사용할 수 있으며, 유지관리 성능이 우수하고, 하부구조를 경제적으로 시공할 수 있다. 이 연구는 교대벽체의 일부를 PSC 거더의 단부 벽체형 블록 형태로 제작한 반일체식교대교량에 대한 것으로, 온도신축에 따라 종방향 이동에 저항 역할을 하는 프리캐스트 블록을 활용한 PSC 거더이다. 프리캐스트 블록 PSC 거더는 거더 단부에 프리캐스트 블록을 일체 타설하여 제작하며, 교대벽체 위에 단순거치한 후 무수축 콘크리트와 합성하는 방식으로 시공한다. 따라서 본 연구는 재하실험을 통해 구조계산한 결과에 비교하고자 하며, 나아가 실제 시공된 반일체식교대교량의 토압 및 상부구조 변위 계측하여 이를 분석을 통한 구조성능 평가하였다.

창경궁 영춘헌과 집복헌의 건축과 변화 (A study on the construction and change-over of Yeongchunheon and Jipbokheon in Changgyeonggung Palace)

  • 이종서;김버들
    • 건축역사연구
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    • 제31권5호
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    • pp.35-44
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    • 2022
  • Although Changgyeong-gung was devastgated by Japanease invasion in 1592, it was restored during the reign of Gwanghaegun, had remembered of early Joseon danasty's architecturural order. It was destroyed several times by fire after that but was rebuilt immedieately. There are Donggol-do and Donggol-dohyeong, so we can fine the change of architectures in Changgyeong-gung. Jibbokheon(集福軒) and Yeongchunheon(迎春軒) are marked in another location and architectures in Donggon-do and Donggon-dohyeong. The reason has been known that it was rebuilt after the fire in 1830. As a result of reviewing the record of birth of crown prince Sado and movement of coffin of King Jeong-jo in funeral ceremony, it was confirmed that notation of Jibbokheon and Yeongchunhyeon was misprinted. In particular, Yeongchunheon confirmed the possibility that the existing building was built by extending it while applying the asymmetrical building with four-purlins structure method during the reign of King Jeongjo, and that it was reconstructed by moving Yeonyeonghap when it was destroyed by fire 1830. And although now Jibbokheon and Yeongchunhyeon(延英閤) are connected, nothern part of Jibbokheon did not burn in the fire, so it was judged that original architectural plan were maintained until now. The current building north of Jibbokheon was built before 1695 (21st year of King Sukjong), which was first identified in the Gunggeolji(宮闕志), and there is a possibility that it may have been a part of Janggyeongmun(長慶門) inner corridor built before 1633. The present building north of Jibbokheon has great architectural significance in that it maintains the structural method of the early Joseon Dynasty which was often applied to buildings with a small scale of inner palace.

국민연금의 지분율과 기업 배당성향 간의 관계: 스튜어드십 코드 도입 이후 변화를 중심으로 (The Relationship between the National Pension Service's Shareholding and Dividend Propensity: Focus on the Changes since the Stewardship Code.)

  • 원상희;전봉걸
    • 아태비즈니스연구
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    • 제12권3호
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    • pp.329-342
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    • 2021
  • Purpose - The purpose of this study is to analyze the effect of investment by the National Pension Service, which has a high share as a single fund, on the dividend payout ratio. Design/methodology/approach - This study secured a share through DART of the Financial Supervisory Service and disclosure of the National Pension Service. We also used a fixed-effects model and 2SLS to analyze the data. Findings - First, it was found that there was a possibility of conflicting interests among shareholders concerning the company's dividend payment policy. Second, in the range of 3% to 4.9% of the National Pension Service shareholding, an additional increase in the holding ratio was found to have a positive (+) effect on the dividend rate. Third, after the introduction of the Stewardship Code, it was found that the increase in ownership of the fund had a positive (+) effect on the company's dividend payout ratio, regardless of the share ratio range. Moreover, the relationship between the fund ownership and the dividend payout ratio showed a clear positive relationship when free cash flow was high along investment opportunities were low. Research implications or Originality - First, This study included less than 5% of the share in the analysis. Second, We used the recent changes in fund shareholder activities. Third, We tested an instrumental variable to confirm the relationship between the National Pension Service share and the dividend ratio.

경복궁 중건 시 창의궁 함일재의 흥복전 이건에 관한 연구 (A Study on the Relocation of Heungbok-jeon formerly known as the Hamil-jae of Changui-gung Palace in the Reconstruction of Gyeongbok-gung Palace)

  • 홍석주;김버들
    • 건축역사연구
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    • 제31권6호
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    • pp.69-80
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    • 2022
  • This study explains details on Heungbokjeon during the reconstruction of Gyeongbokgung Palace in the 19th century for the first time in 273 years. Hence, the construction of a palace with more than 7,000 Kan(間) made possible in a short stretch of time. Given the fact that its existing architecture was recycled. The antecedent of Heungbokjeon(興福殿) was the Hamiljae(咸一齋) of Changuiggung(彰義宮) which served as the residence of King Yeongjo before he was enthroned. On the other hand, the Changuigung was the outset of Inpyeongwi-gung(寅平尉宮), which was built for the princesses. During the reign of King Hyojong the princess who got married must depart from the Inpyeongwi-gung. This study corroborated the undertaking of modification of its architecture frombeing asymmetrical house to symmetrical most primarily the inner part of the palace through the innovation of Changui-gung and the restoration of Hamijae to Heungbokjeon. Hence, it was confirmed that the Heungbokjeon was the only inner part of the palace that was not burned down by the 2 consecutive fires during the reign of King Gojong, to be more specific these fire happend on his 10th and 13th year of rule. Consequently, the research process of Gyeongbokgung Heungbokjeon can escalate the possibility of considering not only the reconstruction of Gyeongbokgung in the 19th century, as well as the construction of the capital city in the 17th century.