• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 학술회의 논문집 정보 및 제어부문 A
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• pp.127-130
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• 2003

In this paper, a hypothesis in order that the impulse response of a stable linear system does not change sign is suggested. For fixed zeros of the systems, the problem of synthesizing such a system is reduced to the problem of finding a proper denominator polynomial so that the step response of the overall system will not overshoot. The hypothesis is associated with the generalized time constant by Kim[5]. Under the hypothesis, we propose several methods that allow to compose a continuous time LTI systems achieving non-negative impulse response.

• 소음진동
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• 제9권4호
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• pp.813-821
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• 1999

This paper presents the technique using wavelet analysis to solve the seismic response of a steam turbine-generator rotor system subjected to earthquake excitations. A brief review of the wavelet transform and its discretization, time-frequency representation of the earthquake wave and the seismic response for a rotor system is presented. The Daubechies wavelet has been used for describing the time-frequency characteristics of the input and the response in case of a recorded accelerogram during 1995 Hyogoken Nanbu earthquake. Also, the results in the wavelet domain has been illustrated through comparison with the time domain simulation results.

• 한국유체기계학회 논문집
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• 제17권4호
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• pp.70-75
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• 2014

In this paper a analysis method is presented to obtain the steady state dynamic response from the finite element based equations of a rotor-bearing system with initial deflection. The method has been applied to analyze the dynamic response of the two-shaft rotor-bearing system with rigid coupling offset in a heavy duty gas turbine-generator. Bumps in the dynamic response of each rotor system have been observed at each critical speed due to the effect of initial deflection for rigid coupling offset. And, the dynamic responses have been shown to reduce for operating condition changes from cold to hot.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2006년도 춘계학술대회 및 창립 30주년 심포지엄(논문집)
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• pp.215-220
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• 2006

해양오염의 가장 큰 오염원은 선박에 실린 기름들이다. 근래에 들어 HNS(Hazardous and noxious substances)로 명명하는 유해위험물질의 운반이 점차 증가함에 따라 국가적으로 기름만을 해양오염의 방제 대상으로 두지 않고 유해위험물질을 모두 해양오염 및 인명안전에 관계된다는 것에 관심사를 집중시키고 있다. HNS 물질의 해양 사고 발생 시 가장 중요한 것은 얼마나 신속하고 정확하게 반응을 하는가 하는 것이 중요한 관점이다. 이러한 중요한 사항을 위한 결정을 위해 필요한 HNS 방제정보지원시스템의 구축에 대해서 소개하고자 한다.

• Structural Engineering and Mechanics
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• 제15권2호
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• pp.239-248
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• 2003

The dynamic response analysis of closed loop control system based on probability for the intelligent truss structures with random parameters is presented. The expressions of numerical characteristics of structural dynamic response of closed loop control system are derived by means of the mode superposition method, in which the randomness of physical parameters of structural materials, geometric dimensions of active bars and passive bars, applied loads and control forces are considered simultaneously. The influences of the randomness of them on structural dynamic response are inspected by several engineering examples and some significant conclusions are obtained.

• 한국공간구조학회논문집
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• 제19권1호
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• pp.53-64
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• 2019

The objective of this study is to investigate the earthquake response for the design of 100m spanned single-layer lattice dome. The plastic hinge analysis and eigenvalue buckling analysis are performed to estimate the ultimate load of single-layered lattice domes under vertical loads. In order to ensure the stability of lattice domes, it is investigated for the plastic hinge progressive status by the pushover increment analysis considering the elasto-plastic connection. One of the most effective methods to reduce the earthquake response of large span domes is to install the LRB isolation system of a dome. The authors discuss the reducing effect for the earthquake dynamic response of 100m spanned single-layered lattice domes. The LRB seismic isolation system can greatly reduce the dynamic response of lattice domes for the horizontal and vertical earthquake ground motion.

• 한국응급구조학회지
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• 제22권2호
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• pp.51-65
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• 2018

Purpose: The purpose of this study was to investigate experiences of violence with patients or family members by paramedics working at emergency rooms. Methods: A questionnaire was administered from June 1 to 31, 2017 to 225 paramedics working at 27 emergency medical centers. The collected data were analyzed with SPSS statistics ver 24.0 program. Results: Within the past year, 208(92.9%) of 224 participants experienced violence among whom 202(90.2%) experienced verbal abuse, 193(86.2%) experienced physical threat, 89(39.7%) experienced physical violence, and 52(23.2%) experienced sexual violence. The level of violence response depending on the overlapping experience of violence type showed significant difference from emotional response (p= .001), social response (p= .001), physical response (p= .004), and overall violence response (p= .001). Conclusion: In conclusion, paramedics are frequently exposed to violence in the emergency rooms, of which they mostly experience verbal abuse. In addition, because the reporting system in the event of violence and the coping process are not well-informed, paramedics are unable to sufficiently utilize the reporting system and programs established within the institution. Therefore, the support of the legal system is needed to create a safe working environment for the medical staff who work in the emergency medical centers.

• 한국방재학회 논문집
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• 제7권2호통권25호
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• pp.25-33
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• 2007

선진국에서는 폭염이 발생하면 폭염경고시스템을 바탕으로 경보가 발령되며 이에 따른 지방자치단체(지자체)별 행동요령이나 대응 시나리오가 구축되어 있다. 우리나라도 소방방재청에서 수립한 폭염종합대책을 토대로 지자체별로 계획을 세우고 있으나, 폭염경고시스템이나 폭염취약계층에 대한 정의 및 구체적인 대응 시나리오가 마련되어 있지 않다. 이에 본 연구에서 예방 및 대비, 대응, 복구의 재해관리 단계로 나누어 외국의 선진 사례를 분석하고, 우리나라 폭염종합대책의 현황과 문제점을 살펴보았으며 나아가 폭염종합대책의 위상강화와 내용을 보완하는 운영방안을 도출하였다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 1994년도 추계학술대회논문집; 한국종합전시장, 18 Nov. 1994
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• pp.35-39
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• 1994

One of the important characteristics of the response of nonlinear systems is the existence of subharmonic resonances. When some conditions in parameter space are satisfied. It is possible even in the presence of damping for a periodically excited nonlinear system to possess a response which is the combination of a contribution at the excitation frequency and a component at the system natural frequency. The system natural frequency being a submultiple of the excitation frequency implies that the resulting response is a subharmonic oscillation. In general, there also co-exists, for the system, a response at the excitation frequency, and initial conditions determine which of the steady-state responses is achieved in an experiment or a numerical simulation. In single-degree-of-freedom systems with harmonic excitation, depending on the type of the nonlinearity, e.g., cubic or quadratic the frequency of subharmonic response is respectively, one-third or one-half of that of the excitation frequency. Although subharmonic resonance is one of the principal characteristics of a nonlinear system the subharmonic responses of structures in the presence of internal resonances have been studied very rarely. In this work, we consider subharmonic responses in the two-mode approximation of the plate equations. It is assumed that the two modes are in one-to-one internal resonance. Constant and periodic steady-state solutions of the averaged equations are studied. Finally, the results of direct time integration of the original equations of motion are presented and compared with those obtained from the averaged equations.

• 전기학회논문지
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• 제64권9호
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• pp.1269-1275
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• 2015

Turbine-generator torsional response is caused by interaction between electrical transient air-gap torque and mechanical characteristics of turbine-generator shafts. There are various factors that affects torsional interaction such as fault, circuit breaker switching and generator mal-synchronizing, etc. Fortunately, we can easily simulate above torsional interaction phenomena by using ElectroMagnetic Transient Program (EMTP). However, conventional EMTP shows the incomplete response of super- synchronous torsional mode since it does not consider turbine blade section. Therefore, in this paper, we introduced mechanical-electrical analogy for detailed modeling of turbine-generator shaft system including low pressure turbine blade section. In addition, we derived the natural frequencies of modeled turbine-generator shaft system including turbine blade section and analyzed the characteristics of mechanical torque response at shaft coupling and turbine blade root area according to power system balanced/unbalanced faults.