• The Journal of the Acoustical Society of Korea
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• 제14권2E호
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• pp.12-18
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• 1995

용량형 압력센서의 거동을 유한요소법으로 해석하였다. 센서는 원형박막과 이를 강성지지대에 연결하는 몇 개의 다리들로 구성이 되면, 센서재료는 실리콘 단결정이다. 성능에 영향을 미치는 센서구조의 형상변화를 유한요소 해석법을 이용하여 알아보았는데, 고려한 변수들은 원형박막의 직경 및 두께, 그리고 다리는 개수 등이다. 이들 변수의 변화에 따른 마이크의 정적거동해석, 동적 거동해석, 그리고 감도해석 등의 결과를 분석하여 제작하고자 하는 총 15개의 미소형 압력센서 구조중 최선의 것을 결정하였다.

• 센서학회지
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• 제26권5호
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• pp.331-337
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• 2017

A readout circuit for a tactile sensor pad based on force sensing resistors was proposed, which was composed of an analog signal conditioning circuit and a digital circuit with a microcontroller. The conventional signal conditioning circuit has a dc offset voltage in the output signal, which results from the reference voltage applied to the FSR devices. The offset voltage reduces the dynamic range of the circuit and makes it difficult to operate the circuit under a low voltage power supply. In the proposed signal conditioning circuit, the dc offset voltage was removed completely. The microcontroller with A/D converter and D/A converter was used to enlarge the measurement range of pressure. For this, the microcontroller adjusts the FSR reference voltage according to the resistance magnitude of FSR under pressure. The operation of the proposed readout circuit which was connected to a tactile sensor pad with $5{\times}10$ FSR array was verified experimentally. The experimental results show the proposed readout circuit has the wider measurement range of pressure than the conventional circuit. The proposed circuit is suitable for low voltage and low power applications.

• 대한기계학회논문집A
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• 제35권3호
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• pp.299-308
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• 2011

본 논문은 항만공사용 로봇의 실린더 길이 측정을 위한 압력 옵서버 개발이다. 로봇의 유압 실린더 제어를 위해 변위 센서가 필요하며 일반적으로 LVDT, 리니어 스케일 등이 사용된다. 이러한 센서는 실린더 외부몸통에 장착되므로 건설현장과 같은 열악한 환경에서 사용할 경우 내구성이 좋지 못하다. 본 논문에서는 압력센서를 이용하여 간접적으로 실린더 길이를 측정한다. 압력센서는 유압 밸브박스 내부에 장착되어 외부충격으로부터 보호되며 방수가 용이하다. 오일을 압축성 매개체로 간주하여 실린더의 위치와 속도 함수인 동적압력 방정식을 유도하고 RLS를 이용하여 실린더가 전진, 후진 리미트에 도달할 때마다 파라미터를 갱신한다.

• Composites Research
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• 제31권5호
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• pp.238-245
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• 2018

수압램 현상은 전투용 항공기의 주요 전투 손상 중 하나이며, 항공기 기체 생존성 평가에 중요한 영향을 미친다. 수압램 효과는 유체-구조물간의 상호관계를 통하여 나타나며, 구조물의 동적 변형률을 측정하여 파손 거동 및 파손 여부를 확인할 수 있다. 본 논문에서는 수압램 현상을 모사할 수 있는 수압램 시험 장치를 이용하여 수압램에 의한 복합재 T-Joint의 파손 시험을 수행하였다. 또한 계측기기의 입력 정전용량과 시간 상수 확인을 위해 PVDF 센서 보정 시험을 수행하였다. 복합재 T-Joint에 스트레인 게이지와 전하증폭기를 사용하지 않은 PVDF 센서를 부착하여 수압램 현상에 의한 복합재 T-Joint의 동적 변형률을 측정하였다. PVDF 센서와 스트레인 게이지의 동적 변형률을 이용하여 복합재 T-Joint의 파손 거동 및 파손 여부를 확인하였다.

• Smart Structures and Systems
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• 제19권2호
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• pp.151-161
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• 2017

A new method is developed to estimate road profile in order to estimate IRI based on the ASTM standard. This method utilizes an accelerometer and a Dynamic Tire Pressure Sensor (DTPS) to estimate road roughness. The accelerometer measures the vertical axle acceleration. The DTPS, which is mounted on the tire's valve stem, measures dynamic pressure inside the tire while driving. Calibrated transfer functions are used to estimate road profile using the signals from the two sensors. A field test was conducted on roads with different quality conditions in the city of Brockton, MA. The IRI values estimated with this new method match the actual road conditions measured with Pavement Condition Index (PCI) based on the ASTM standard, images taken from an onboard camera and passengers' perceptions. IRI has negative correlation with PCI in general since they have overlapping features. Compared to the current method of IRI measurement, the advantage of this method is that a) the cost is reduced; b) more space is saved; c) more time is saved; and d) mounting the two sensors are universally compatible to most cars and vans. Therefore, this method has the potential to provide continuous and global monitoring the health of roadways.

• 한국운동역학회지
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• 제26권3호
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• pp.285-292
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• 2016

Objective: This study collected data on muscle fatigue and ground reaction force during walking to provide a basis for development of custom-fitted outdoor walking shoes. The study analyzed an upright body exercise program using spine stabilization technique to determine the effect on foot plantar pressure in archers, demonstrate the effectiveness of upright body exercise, and develop a new, effective, and efficient training program. Method: A 12-week upright body exercise program was evaluated for the effect on plantar pressure in archers. Ten prize-winning archers (3 men, 7 women) in B metropolitan city, each with ${\geq}10years$ of experience, were given an explanation of the content and purpose of the program, and provided informed consent. Upright body exercise was performed 3 times a week for 12 weeks. A resistive pressure sensor was used to measure foot plantar pressure distribution and analyze quantitative information on variation in postural stability and weight shifting in dynamic balance during shooting, as well as plantar pressure in static balance with the eyes open and closed. Results: There were no significant differences in foot plantar pressure before and after participation in the exercise program. There was no statistically significant difference in foot plantar pressure in static balance with the eyes open or closed, or in foot plantar pressure in dynamic balance during shooting. Conclusion: An upright body exercise program had positive effects on foot plantar pressure in static and dynamic balance in archers by reducing body sway and physical imbalance during shooting and with eyes closed. This program is expected to help archers improve their posture and psychological state, and thereby improve performance.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2007년도 추계학술대회 논문집
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• pp.163-165
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• 2007

Direct Instantaneous Pressure Control(DIPC) method of SRM using pressure predict method is presented in this paper. A hydraulic pump system has an inherent defect that its dynamic behavior causes by interaction between the sensor and hydraulic load. It will make sometimes the whole system become oscillatory and unstable. Proposed system integrates direct instantaneous torque control (DITC) and Smith predictor to improve dynamic performance and stabilization. The proposed hydraulic oil pump system is verified by computer simulation and experimental results.

• 한국운동역학회지
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• 제28권1호
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• pp.9-18
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• 2018

Objective: This study aimed to analyze how the upright body type exercise program affected body balance and record of archers. This study aimed to prove the effectiveness of upright body type exercise, on this basis, in enhancing the performance of archery players. Method: A total of 14 archers (7 men and 7 women) in B Metropolitan City who had ${\geq}4years$ of career in archery and were given explanation of its contents and purpose before giving spontaneous consent to the experiment were enrolled in the study. The upright body type exercise program was implemented thrice a week for 12 weeks, with higher exercise intensity with time. A resistive pressure sensor, Gaitview AFA-50, was used to measure the foot plantar pressure distribution and analyze quantitative information concerning variation in posture stability and weight shift in dynamic balance of foot plantar pressure in shooting and static balance of plantar pressure with the eyes open and closed and the change in archery record accompanying the change in body balance. Results: As for the differences in foot plantar pressure between before and after participation in the upright body type exercise program, there was no significant difference in static balance of foot plantar pressure with the eyes open, and there was statistically significant difference at the ${\alpha}=.05$ significance level in static balance of foot plantar pressure with the eyes closed or in dynamic balance of foot plantar pressure in shooting. There was statistically significant difference at the ${\alpha}=.05$ significance level in archery record. Conclusion: The upright body type exercise program had positive effects on static and dynamic balance of foot plantar pressure by allowing archers to experience less body sway and physical imbalance in shooting with closed eyes and positive effects on archery record. Thus, the program is expected to help archers correct their posture and perform better.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2012년도 제38회 춘계학술대회논문집
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• pp.65-69
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• 2012

산화제 과잉 예연소기의 연소시험을 통해 예연소기 각 부위에서 압력을 측정하였다. 측정결과는 FFT를 통해 주파수 해석이 이루어 졌으나 정압 센서의 한계로 인하여 250 Hz 이상의 주파수에는 자세한 연구가 이루어지지 못하였다. 정압 데이터 분석결과 30 Hz의 하모닉스가 연소압과 산소입구에서 관측되었다. 따라서 연소압의 변화는 O/F 변화로 인한 것으로 파악된다. 반면에 동압센서 신호를 살펴보면 정압센서에서 확연히 나타났던 주파수보다 훨씬 더 명확한 주파수가 보다 높은 Hz에서 관측되는 것을 알 수 있었다.

• Nuclear Engineering and Technology
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• 제55권7호
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• pp.2642-2649
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• 2023

A real-time unmeasured dynamic response prediction process for the nuclear power plant pressure pipeline is proposed and its performance is tested in the test-loop system (KAERI). The aim of the process is to predict unmeasurable or unreachable dynamic responses such as acceleration, velocity, and displacement by using a limited amount of directly measured physical responses. It is achieved by combining a well-constructed finite element model and robust inverse force identification algorithm. The pressure pipeline system is described by using the displacement-pressure vibro-acoustic formulation to consider fully filled liquid effect inside the pipeline structure. A robust multiphysics modal projection technique is employed for the real-time sensor synchronized prediction. The inverse force identification method is also derived and employed by using Bathe's time integration method to identify the full-field responses of the target system from the modal domain computation. To validate the performance of the proposed process, an experimental test is extensively performed on the nuclear power plant pressure pipeline test-loop under operation conditions. The results show that the proposed identification process could well estimate the unmeasured acceleration in both frequency and time domain faster than 32,768 samples per sec.