• 전력전자학회:학술대회논문집
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• 전력전자학회 2000년도 전력전자학술대회 논문집
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• pp.241-244
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• 2000

한전은 국가경제 성장에 따라 늘어나는 발전설비에 대한 운영효율의 향상과 고장발생의 예방 사고시 운전원들의 운전능력 배양 등을 목적으로 운영요원 훈련용 시뮬레이터를 국산화 개발하여 운영하고 있다 훈련용 시뮬레이터를 구성하는 시스템들 중 발전소 안전계통과 발전소 감시계통을 시뮬레이션하는 PPC(Plant Processing Computer) 시스템이 있다 VMS(Vibration Monitoring System) 는 PPC의 여러계통들 중 하나로서 발전소의 터빈 발전기 펌프 등의 진동을 감시하는 시스템이다 본 논문에서는 시뮬레이터의 VMS를 개발하기 위해 적용한 시뮬레이tus 모델 알고리즘 그리고 모델에서 계산된 진동값을 PC의 모니터에 나타내는 Display 시스템등에 대해 기술하고자한다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2001년도 추계학술대회논문집 II
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• pp.633-639
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• 2001

This paper proposes a knowledge-based expert system. which is assembled into hardware organized with sensor module. AID converter, USB. data acquisition PC and software composed of monitoring and diagnosis module combined with a frame-based method using Sohre's chart and a rule-based method. Vibration signals using various sensors are acquired by AID converter. transferred into PC and processed to obtain a continuous monitoring of the machine status displayed into several plots. Through combining frame-base which covers wide vibration causes with rule-base which gives relatively specified diagnosis results, high accuracy of fault diagnosis can be guaranteed and knowledge base can be easily extended by adding new causes or symptoms. Some examples using experimental data show the good feasibility of the proposed algorithm for condition monitoring and diagnosis of industrial rotating machinery.

• Smart Structures and Systems
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• 제7권2호
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• pp.83-102
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• 2011

As a testbed for various structural health monitoring (SHM) technologies, a super-tall structure - the 610 m-tall Guangzhou Television and Sightseeing Tower (GTST) in southern China - is currently under construction. This study aims to explore state-of-the-art wireless sensing technologies for monitoring the ambient vibration of such a super-tall structure during construction. The very nature of wireless sensing frees the system from the need for extensive cabling and renders the system suitable for use on construction sites where conditions continuously change. On the other hand, unique technical hurdles exist when deploying wireless sensors in real-life structural monitoring applications. For example, the low-frequency and low-amplitude ambient vibration of the GTST poses significant challenges to sensor signal conditioning and digitization. Reliable wireless transmission over long distances is another technical challenge when utilized in such a super-tall structure. In this study, wireless sensing measurements are conducted at multiple heights of the GTST tower. Data transmission between a wireless sensing device installed at the upper levels of the tower and a base station located at the ground level (a distance that exceeds 443 m) is implemented. To verify the quality of the wireless measurements, the wireless data is compared with data collected by a conventional cable-based monitoring system. This preliminary study demonstrates that wireless sensing technologies have the capability of monitoring the low-amplitude and low-frequency ambient vibration of a super-tall and slender structure like the GTST.

• Smart Structures and Systems
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• 제6권7호
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• pp.811-833
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• 2010

Vibration control and health monitoring of building structures have been actively investigated in recent years but treated separately according to the primary objective pursued. This paper presents a general approach in the time domain for integrating vibration control and health monitoring of a building structure to accommodate various types of control devices and on-line damage detection. The concept of the time-domain approach for integrated vibration control and health monitoring is first introduced. A parameter identification scheme is then developed to identify structural stiffness parameters and update the structural analytical model. Based on the updated analytical model, vibration control of the building using semi-active friction dampers against earthquake excitation is carried out. By assuming that the building suffers certain damage after extreme event or long service and by using the previously identified original structural parameters, a damage detection scheme is finally proposed and used for damage detection. The feasibility of the proposed approach is demonstrated through detailed numerical examples and extensive parameter studies.

• Smart Structures and Systems
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• 제10권6호
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• pp.517-546
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• 2012

In this paper, vibration-based methods to monitor damage in foundation-structure interface of harbor caisson structure are presented. The following approaches are implemented to achieve the objective. Firstly, vibration-based damage monitoring methods utilizing a variety of vibration features are selected for harbor caisson structure. Autoregressive (AR) model for time-series analysis and power spectral density (PSD) for frequency-domain analysis are selected to detect the change in the caisson structure. Also, the changes in modal parameters such as natural frequency and mode shape are examined for damage monitoring in the structure. Secondly, the feasibility of damage monitoring methods is experimentally examined on an un-submerged lab-scaled mono-caisson. Finally, numerical analysis of un-submerged mono-caisson, submerged mono-caisson and un-submerged interlocked multiple-caissons are carried out to examine the effect of boundary-dependent parameters on the damage monitoring of harbor caisson structures.

• Earthquakes and Structures
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• 제2권2호
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• pp.189-206
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• 2011

In this study, the subspace stochastic realization theories (SSR model I and SSR model II) have been applied to a real bridge for estimating its dynamic characteristics (natural frequencies, damping constants, and vibration modes) under ambient vibration. A numerical simulation is carried out for an arch-type steel truss bridge using a white noise excitation. The estimates obtained from this simulation are compared with those obtained from the Finite Element (FE) analysis, demonstrating good agreement and clarifying the excellent performance of this method in estimating the structural dynamic characteristics. Subsequently, these methods are applied to the vibration induced by both strong and weak winds as obtained by remote monitoring of the Kabashima bridge (an arch-type steel truss bridge of length 136 m, and situated in Nagasaki city). The results obtained with this experimental data reveal that more accurate estimates are obtained when strong wind vibration data is used. In contrast, the vibration data obtained from weak wind provides accurate estimates at lower frequencies, and inaccurate accuracy for higher modes of vibration that do not get excited by the wind of lower intensity. On the basis of the identified results obtained using both simulated data and monitored data from a real bridge, it is determined that the SSR model II realizes more accurate results than the SSR model I. In general, the approach investigated in this study is found to provide acceptable estimates of the dynamic characteristics of highway bridges as well as for the vibration monitoring of bridges.

• 한국정밀공학회지
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• 제18권4호
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• pp.72-77
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• 2001

Monitoring of the chatter vibration is necessarily required to do automatic manufacturing system. Therefore, we constructed a sensing system using tool dynamometer in order to monitor of chatter vibration on cutting process. Furthemore, an application of neural network using behavior of principal cutting force signals Is attempted. With the error back propagation trining process, the neural network memorized and classified the feature of principal cutting force signals. From obtained result, it is shown that the chatter vibration can be monitored effectively by neural network.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2008년도 추계학술대회논문집
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• pp.423-428
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• 2008

The monitoring efficiency of the aircraft noise monitoring stations is decided to the reference noise level and the infringement of each monitoring stations. We are calculate the monitoring efficiency of three noise monitoring stations among twelve in the vicinity of Gimpo Int'l Airport. As a result, the monitoring efficiency shows that the noise monitoring stations #3,#5 and #6 are 14.3%, 18.5% and 29.3% respectively, #6 which is underneath the flight track is higher efficiency than another two stations.

• 한국소음진동공학회논문집
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• 제19권1호
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• pp.50-55
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• 2009

The monitoring efficiency of the aircraft noise monitoring stations is decided to the reference noise level and the infringement of each monitoring stations. We calcurates the monitoring efficiency of three noise monitoring station among twelve in the vicinity of Gimpo Int'l Airport. As a result, the monitoring efficiency shows that the noise monitoring stations No#3, No#5 and No#6 are 14.3%, 18.5% and 29.3% respectively, Among them No#6 staion looks higher efficiency than another two stations because of underneath the flight trackas.

• 한국공작기계학회논문집
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• 제13권5호
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• pp.55-61
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• 2004

Chatter monitoring is also important for realizing an unmanned machining system. while many researches were done on this area, it is still a difficult job to detect very small amplitude amount of chattering. A monitoring system using a capacitive spindle displacement sensor was developed to monitor cutting vibration in turning in this research. The variance of the measured spindle displacement signals using the developed sensor was calculated and utilized to quantify the small vibration in machining. The results were compared with variance obtained using a tool dynamometer. The result showed that the developed system could be utilized in monitoring the subtle changes of cutting vibrations with high sensitivity confidence.