• Smart Structures and Systems
• /
• 제2권2호
• /
• pp.171-188
• /
• 2006

This paper deals with damage detection using active Lamb waves. The wavelet transform and empirical mode decomposition methods are discussed for measuring the Lamb wave's arrival time of the group velocity. An experimental system to diagnose the damage in the composite plate is developed. A method to optimize this system is also given for practical applications of active Lamb waves, which involve optimal arrangement of the piezoelectric elements to produce single mode Lamb waves. In the paper, the single mode Lamb wave means that there exists no overlapping among different Lamb wave modes and the original Lamb wave signal with the boundary reflection signals. Based on this optimized PZT arrangement method, five damage localizations on different plates are completed and the results using wavelet transform and empirical mode decomposition methods are compared.

• 한국복합재료학회:학술대회논문집
• /
• 한국복합재료학회 2005년도 춘계학술발표대회 논문집
• /
• pp.46-50
• /
• 2005

Smart skin, a multi-layer structure of composed of a round shape antenna, was designed and fabricated. Tests and analyses was conducted to study its behavior under compressive loads. It was confirmed that the designed smart skin failed due to premature buckling before compression failure. Numerical prediction of structural behavior of smart skin by MSC.NASTRAN agreed well with experimental data.

• 한국의류산업학회지
• /
• 제8권4호
• /
• pp.420-426
• /
• 2006

Korean prior studies on smart clothing seeking complete mixture of clothing and computer with diverse functions in the ubiquitous environment were so mere, while there have been aggressive activities to develop diverse smart clothing products led by the relevant industries and universities in foreign countries. Given prospective growth of the smart clothing market, there should be customers' evaluation of functions and utility of and sensitivity to smart clothing as well. This study conducted a questionnaire to Korean customers in their twenties regarding their perception and liking of and willingness to use smart clothing, and examined the needs of new functions of smart clothing. As a result, the customers in their twenties turned out to like well-designed and comfortable clothing, and be exposed to diverse and continuous computing environment. Also, they have relatively low perception but considerably high liking of smart clothing, indicating their high willingness to use smart clothing products. They cited 'selectable functions' and 'mobile and convenient ' as merits, and 'too expensive' and 'easy to wash' as demerits of smart clothing. In the respect, they proposed many interesting smart clothing ideas, such as 'clothing with automatic temperature-sensing function, which gets higher heat- insulating function by tightening the textile structure in winter and higher ventilating function by loosening the textile structure in summer.' We hope the results of this study will serve basic data for development of more efficient smart clothing in the future.

• 한국IT서비스학회지
• /
• 제19권3호
• /
• pp.139-149
• /
• 2020

There are now many different commercial weather sensors suitable for smart farms, and various smart farm devices are being developed and distributed by companies participating in the government-led smart farm expansion project. However, most do not comply with standard specifications and are therefore limited to use in smart farms. This paper proposed the connecting structure of operating non-standard node devices in smart farms following standard specifications supporting smart greenhouse. This connecting structure was proposed as both a virtual node module method and a virtual node wrapper method. In addition, the SoftFarm2.0 system was experimentally operated to analyze the performance of the implementation of the two methods. SoftFarm2.0 system complies with the standard specifications and supports non-standard smart farm devices. According to the analysis results, both methods do not significantly affect performance in the operation of the smart farm. Therefore, it would be good to select and implement the method suitable for each non-standard smart farm device considering environmental constraints such as power, space, distance of communication between the gateway and the node of the smart farm, and software openness. This will greatly contribute to the spread of smart farms by maximizing deployment cost savings.

• 한국정보통신학회:학술대회논문집
• /
• 한국정보통신학회 2021년도 추계학술대회
• /
• pp.357-359
• /
• 2021

대량 운송 수단인 철도 시스템은 고속화 및 자동화 시대를 넘어 이를 통합한 스마트 철도 시스템으로 진화하고 있다. 이와 같은 스마트 철도 시스템을 구축 및 운용하기 위해서는 5G-R과 같은 모바일 통신 기술과 빅데이터, 딥러닝, 인공지능 및 블록체인과 같은 융복합 정보기술 등이 포괄되는 통신 네트워크 기술이 활용되어야 한다. 본 논문에서는 이와 같은 스마트 철도 시스템을 위한 통신 네트워크 구조를 제안한다. 본 논문에서 제안하는 스마트 철도 통신 네트워크 구조는 고속철도의 안전 운행, 철도 관리, 고객 서비스를 포괄하는 평면단위의 계층구조로 구성되며 필요에 따라 이를 평면간 혼합한 기능을 가질 수도 있다. 본 연구의 결과는 스마트 철도 통신 네트워크의 구축, 운영 및 유지 관리와 철도통신 시스템 표준화 연구 등에 활용될 수 있다.

• 한국공작기계학회논문집
• /
• 제14권3호
• /
• pp.32-37
• /
• 2005

Several types of smart materials and control scheme are available to adjust the structure actively in various external disturbances. A control scheme was introduced for a specific material. But the effectiveness of the control scheme has some limitation according to the choice of the smart materials and the response of the structure. The ER(Electrorheological) fluid is adequate for a large control force, and the PZT(lead zirconate titanate) patches are suitable for small but arbitrary control force at any point of the structure. It can be used for active control of structure by changing the dynamic characteristics of the structure. But it has some difficulty in suppressing the excited vibration in broad band. To compensate this resonance of the controlled structure, a hybrid controller was constructed using PPF(Positive position feedback) control with PZT and ER fluid control.

• 한국소음진동공학회논문집
• /
• 제17권7호
• /
• pp.587-595
• /
• 2007

Performance evaluation of advanced piezoelectric composite actuator is conducted with its application of structural vibration control. Characteristics of MFC(macro fiber composite) actuator are investigated by comparing traditional piezoceramic patch actuator. Finite element modeling is used to obtain equations of motion and boundary effects of smart hull structure with MFC actuator. Dynamic characteristics of the smart hull structure are studied through modal analysis and experimental investigation. LQG control algorithm is employed to investigate active damping of hull structure. It is observed that vibration of hull structure is suppressed effectively by the MFC actuators.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2007년도 춘계학술대회논문집
• /
• pp.1119-1124
• /
• 2007

Performance evaluation of advanced piezoelectric composite actuator is conducted with its application of structural vibration control. Characteristics of MFC (macro fiber composite) actuator are investigated by comparing traditional piezoceramic patch actuator. Finite element modeling is used to obtain equations of motion and boundary effects of smart hull structure with MFC actuator. Dynamic characteristics of the smart hull structure are studied through modal analysis and experimental investigation. LQG control algorithm is employed to investigate active damping of hull structure. It is observed that vibration of hull structure is suppressed effectively by the MFC actuators.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2008년도 춘계학술대회논문집
• /
• pp.299-304
• /
• 2008

Dynamic characteristics of smart hull structure are investigated and active vibration control performance is evaluated. Dynamic model of smart hull structure with surface bonded Macro-fiber Composite (MFC) actuators is established by analytical method. Equations of motion of the host hull structure are derived based on Donnell-Mushtari equilibrium equations for a thin cylindrical shell. A general model for the interaction between hull structure and MFC actuator is included in the dynamic model. Modal analysis is then conducted and mode shapes and corresponding natural frequencies are investigated. After constructing of the optimal control algorithm, active vibration control performance of the proposed system is evaluated. It has been shown that structural vibration can be reduced effectively with proper control input.

• 한국소음진동공학회논문집
• /
• 제18권8호
• /
• pp.832-840
• /
• 2008

Dynamic characteristics of smart hull structure are investigated and active vibration control performance is evaluated. Dynamic model of smart hull structure with surface bonded macro-fiber composite(MFC) actuators is established by analytical method. Equations of motion of the host hull structure are derived based on Donnell-Mushtari equilibrium equations for a thin cylindrical shell. A general model for the interaction between hull structure and MFC actuator is included in the dynamic model. Modal analysis is then conducted and mode shapes and corresponding natural frequencies are investigated. After constructing of the optimal control algorithm, active vibration control performance of the proposed system is evaluated. It has been shown that structural vibration can be reduced effectively with proper control input.