• Bulletin of the Society of Naval Architects of Korea
• /
• v.27 no.2
• /
• pp.107-119
• /
• 1990

에너지 절약을 목적으로 한 최근 신조선의 경우, 구조는 경량화되어 가는 반면 기진력은 증가되고 있다. 즉 주기관은 소수 대구경 기통을 가진 고효율 디젤 엔진이 채용되고 있어 진동 유발요인은 증가되고 있다. 따라서 설계초기부터 진동제어 목표를 세우고 설계 단계마다 진동을 예측 진단하고, 이의 대책을 세우는 방진 시스템이 요구된다. 본문에서는 이러한 시스템 개발의 일환으로 최근 현대중공업에서 건조한 선박 진동 수준 및 진동 요인 변천을 검토하고 추후 개정

• Proceedings of the KIEE Conference
• /
• 2011.07a
• /
• pp.2039-2040
• /
• 2011

자기공명영상에서 심장의 기능을 진단에 필요한 심장 영상을 얻기 위해서는 심장의 움직임을 모니터 할 수 있는 ECG나 pulse oximeter 등의 장비로 동기를 맞추어 주기위한 트리거 신호가 필요하다. 본 논문은 심장의 움직임을 다른 장비의 도움 없이 동기화하여 자기공명 심장 영상을 재구성하는 새로운 방법을 나선주사영상기법에 적용하여 제안하였다.

• Proceedings of the Korean Institute of Industrial Safety Conference
• /
• 2000.06a
• /
• pp.283-289
• /
• 2000

화학공장에서 사고의 원인은 설비의 이송 체결부에서 유해화학 물질의 누출에 의한 경우가 큰 비중을 차지한다. 따라서, 설비의 접합 체결부에서 발생되는 누출현상은 진동원에 대한 이상을 제거하지 않는 한 계속 발생되므로 설비의 주기적인 감시기능이 필수적으로 요구되지만 현재까지는 작업자의 오감에 의하여 정성적인 평가로 대치하는 경우가 대부분이다. (중략)

• Journal of the korean veterinary medical association
• /
• v.35 no.1
• /
• pp.16-21
• /
• 1999

암캐에 있어서 번식장애의 병력이 있는가를 검사하는 것은 상당히 어려운 문제이다. 많은 축주들은 번식장애를 일으킨 암캐들 중의 어떤 개를 소유하게 되었을 것이며 이는 과거에 의학적 문제에 관한 정확한 지식도 가지고 있지 않을 수 있으며 불안전한 상태 일 수도 있기 때문이다. 동물을 소유한 축주로부터 병력을 알았다고 할지라도 올바른 평가를 하는데 도움이 되지 않을 수도 있으며 많은 거리가 있을수도 있다. 그러나 병력을 통하여 적당한 진단계획을 세우는 것이 많은 가치가 있다면 병력을 얻는데 모든 노력을 기울여야만 한다. 병력은 동물의 번식능력에 대한 기록, 발정주기, 발정간의 기간, 음부의 분비물, 과거 분만 곤란 및 강아지의 생존률 등이 포함되어야 할 것이다.

• Proceedings of the KIEE Conference
• /
• 2000.07c
• /
• pp.1939-1941
• /
• 2000

Nondestructive and destructuve insulation tests were performed the high voltage rotating machine in the local thermal power plants. Nondestructive tests include measurements of insulation resistance. polarization index, AC current. tan$\delta$, partial discharge. Destructive tests include measurements of AC hipot and DC hipot. This paper propose to establish the insulation diagnosis cycle for high voltage rotating machine.

• 대한생식의학회:학술대회논문집
• /
• 2001.06a
• /
• pp.43-44
• /
• 2001

• Proceedings of the Korean Nuclear Society Conference
• /
• 1996.11b
• /
• pp.703-710
• /
• 1996

본 연구에서는 영광 3,4호기 원자로의 Core Support Barrel 거동을 중성자 잡음해석을 이용하여 분석하였다. 분석 방법은 원자로 노외계측기에서 취득한 교류 성분의 중성자 잡음 신호를 주파수분석하므로서 얻어진 PSD, Phase, Coherence 등을 이용하였다. 영광 3,4호기의 1 주기 동안의 신호를 분석결과, CSB의 Beam Mode 주파수는 영광 3호기의 경우 BOL, MOL, EOL에서 각각 7.75∼8.5Hz, 7.75Hz, 7.25∼7.75Hz로 나타났고, 영광 4호기 BOL에서 8.5∼8.75Hz 임이 도출되었다. 본연구 결과는 한국형 원전의 원자로 내부구조물의 진동 특성을 파악하고 운전중 CSB건전성 진단을 위한 기초 자료로 활용할 수 있다.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.26 no.2
• /
• pp.43-50
• /
• 2022

Even though the structural safety is confirmed in the design stage, the structural safety is not guaranteed in the construction stage because the structural system is not completed. In addition, since the construction period is shorter than the period of use of the building after completion, it is excessive to apply the same seismic load to the construction stage as in the design stage. ASCE 37-14 presents the concept of seismic load reduction factor during construction, but does not provide a clear application method. Therefore, in this study, the seismic load reduced according to the return period was applied to the example model of a residential middle-rise RC building. The construction stage of the example model was divided into five-story units, and seismic load with the change of the return period was applied to the construction stage models to analyze the change of seismic load during construction and to check the sectional performances of structural members. By comparing the design strength ratio of the shear wall at the design stage and the construction stage, the range of seismic load magnitudes that can assure the safety during construction of a residential middle-rise RC building was analyzed in terms of the return period.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.28 no.1
• /
• pp.70-81
• /
• 2024

In this study, Tridimensional Hybrid Isolation System(THIS) was proposed as a vibration isolator for traffic loads, combining vertical and horizontal isolation systems. Its efficacy in improving serviceability for vertical vibration was analytically evaluated. Firstly, for the analysis, the major vibration modes of the existing apartment were identified through eigenvalue analysis for the system and pulse response analysis for the bedroom slab using commercial structural analysis software. Subsequently, a 16-story model with horizontal, vertical and rotational degrees of freedom for each slab was numerically organized to represent the achieved modes. The dynamic analysis for the measured acceleration from an adjacent ground to high-speed railway was performed by state-space equations with the stiffness and damping ratio of THIS as variables. The result indicated that as the vertical period ratio increased, the threshold period ratio where the slab response started to be suppressed varied. Specifically, when the period ratio is greater than or equal to 5, the acceleration levels of all slabs decreased to approximately 70% or less compared to the non-isolated condition. On the other hand, it was ascertained that the influence of damping ratios on the response control of THIS is inconsequential in the analysis. Finally, the improvement in vertical vibration performance of THIS was evaluated according to design guidelines for floor vibration of AIJ, SCI and AISC. It was confirmed that, after the application of THIS, the residential performance criteria were met, whereas the non-isolated structure failed to satisfy them.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.28 no.4
• /
• pp.37-47
• /
• 2024

This study proposes a track maintenance quantity estimation model that considers evolution of rail fatigue damage and ballast settlement based on actual maintenance data from the Gyeongbu high-speed railway, and revises the existing life cycle cost (LCC) model for railway track. Using this model, maintenance quantities and life cycle costs based on different track quality levels are evaluated and discussed. According to the results, it is confirmed that applying the track maintenance quantity estimation model that accounts for rail fatigue damage and ballast settlement allows us to reasonably estimate maintenance costs close to the actual data. The track quality coefficient significantly influences both rail and ballast maintenance quantities, with ballast maintenance having a greater impact than rail maintenance. Additionally, as train speed increases, both rail and ballast maintenance quantities rise. Moreover, a higher track quality coefficient leads to a steeper increase in maintenance quantities with increasing train speed. Consequently, LCC also exhibits a faster growth rate over time with higher track quality coefficients and faster train speeds, resulting from an increased proportion of maintenance costs.