• 한국소음진동공학회논문집
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• 제14권10호
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• pp.1007-1014
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• 2004

This paper presents a study of low frequencies volume velocity vibration control of a smart panel in order to reduce sound transmission. A distributed piezoelectric quadratically shaped polyvinylidene fluoride (PVDF) polymer film is used as a uniform force actuator and an array of $4\;{\times}\;4$ accelerometer is used as a volume velocity sensor for the implementation of a single-input single-output control system. The theoretical and experimental study of sensor-.actuator frequency response function shows that this sensor-actuator arrangement provides a required strictly positive real frequency response function below about 900 Hz. Direct velocity feedback could therefore be implemented with a limited gain which gives reductions of about 15 dB in vibration level and about 8 dB in acoustic power level at the (1,1) mode of the smart panel. It has been also shown that the shaping error of PVDF actuator could limit the stability and performance of the control system.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2003년도 춘계학술대회논문집
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• pp.368-373
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• 2003

This paper presents a study of low frequencies volume velocity vibration control of a smart panel in order to reduce sound transmission. A distributed piezoelectric quadratically shaped polyvinylidene fluoride (PVDF) polymer film is used as a uniform force actuator and an array of 4$\times$4 accelerometer is used as a volume velocity sensor for the implementation of a single-input single-output con rot system. The theoretical and experimental study of sensor-actuator frequency response function sho vs that this sensor-actuator arrangement provides a required strictly positive real frequency response function below about 900Hz. Direct velocity feedback could therefore be implemented with a limited gain which gives reductions of about 15㏈ in vibration level and about 8 ㏈ in acoustic power level at the (1, 1) mode of the smart Panel. It has been also shown that the shaping error of PVDF actuator could limit he stability and performance of the control system.

• World Technopolis Review
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• 제8권1호
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• pp.59-70
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• 2019

Where is a better place to live? In the coming era, this should be more than simply a livable place. It should be an adaptable place that has a flexible system adaptable to any new situation in terms of diversity. Customization and real-time operation are needed in order to realize this technologically. We expect a smart city to have a flexible system that applies technologies of self-monitoring and self-response, thereby being a promising city model towards being a better place to live. Energy demand and supply is a crucial issue concerning our expectations for the flexible system of a smart city because it is indispensable to comfortable living, especially city living. Although it may seem that energy diversification, such as the energy mix of a country, is a matter of overriding concern, the central point is the scale of place to build grids for realizing sustainable urban energy systems. A traditional hard energy path supported by huge centralized energy systems based on fossil and nuclear fuels on a national scale has already faced difficult problems, particularly in terms of energy flexibility/resilience. On the other hand, an alternative soft energy path consisting of small diversified energy systems based on renewable energy sources on a local scale has limitations regarding stability, variability, and supply potential despite the relatively light economic/technological burden that must be assumed to realize it. As another alternative, we can adopt a holonic path incorporating an alternative soft energy path with a traditional hard energy path complimentarily based on load management. This has a high affinity with the flexible system of a smart city. At a system level, the purpose of all of the paths mentioned above is not energy itself but the service it provides. If the expected energy service is fixed, the conclusive factor in choosing a more appropriate system is accessibility to the energy service. Accessibility refers to reliability and affordability; the former encompasses the level of energy self-sufficiency, and the latter encompasses the extent of energy saving. From this point of view, it seems that the small diversified energy systems of a soft energy path have a clear advantage over the huge centralized energy systems of a hard energy path. However, some insuperable limitations still remain, so it is reasonable to consider both energy systems continuing to coexist in a multiplexing energy system employing a holonic path to create and maintain reliable and affordable access to energy services that cover households'/enterprises' basic energy needs. If this is embodied in a smart city concept, this is nothing else but smart energy inclusion. In Japan, following the Fukushima nuclear accident in 2011, a trend towards small diversified energy systems of a soft energy path intensified in order to realize a nuclear-free society. As a result, the Government of Japan proclaimed in its Fifth Strategic Energy Plan that renewable energy must be the main source of power in Japan by 2050. Accordingly, Sony vowed that all the energy it uses would come from renewable sources by 2040. In this situation, it is expected that smart energy inclusion will be achieved by the Japanese version of a smart grid based on the concept of a minimum cost scheme and demand response.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2018년도 춘계학술대회
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• pp.232-234
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• 2018

본 논문에서는 RFID 태그와 리더로 구성되는 비접촉식 RFID 스마트 태그 시스템을 개발하였다.. 이시스템은 13.56MHz의 저주파수 대역으로 디자인하였다. 개발된 RFID 스마트 태그 보드는 AVR을 이용하여 디자인되었으며 시뮬레이션을 통하여 응답속도가 개선되는 결과를 얻었다. 또한 RFID 태그에 대한 회로 디자인, 시뮬레이션, 실험 결과를 설명하였다.

• KIEAE Journal
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• 제9권2호
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• pp.27-36
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• 2009

Due to rapid advances in science and technology and peoples life value, multi-dimensional functionality of the house has been possible and demanded. Among them, intellectual function and health support function appeared prominent and the former can support the later. The purpose of this study was to delineate health support planning features for smart home. Thirty six planning elements were extracted for initial pool for survey to find out what consumers demanded. Two hundred and nine data were collected through the web-survey. Important planning features were identified in relation to three different health dimensions that is physical/physiological, psychological, and social health. Generally consumers' responses were positive for all features. Major health friendly features highly demanded by consumers were found gas detect system, security system, and a call alarm system. The result of this study is expected to be used as a basic reference to develop strategies for smart home and to grasp current housing culture.

• 한국해양공학회지
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• 제35권4호
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• pp.266-272
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• 2021

Mooring systems are among the most important elements employed to control the motion of floating offshore structures on the sea. Considering the use of polymer material, a new method is proposed to address the creep characteristics rather than the method of using a tension load cell for measuring the tension of the mooring line. This study uses a synthetic mooring rope made from a polymer material, which usually consists of three parts: center, eye, and splice, and which makes a joint for two successive ropes. We integrate the optical sensor into the synthetic mooring ropes to measure the rope tension. The different structure of the mooring line in the longitudinal direction can be used to measure the loads with the entire mooring configuration in series, which can be defined as SMART (Smart Mooring and Riser Truncation) mooring. To determine the characteristics of the basic SMART mooring, a SMART mooring with a diameter of 3 mm made of three different polymer materials is observed to change the wavelength that responds as the length changes. By performing the longitudinal tension experiment using three different SMART moorings, it was confirmed that there were linear wavelength changes in the response characteristics of the 3-mm-diameter SMART moorings. A 54-mm-diameter SMART mooring is produced to measure the response of longitudinal tension on the center, eye, and splice of the mooring, and a longitudinal tension of 100 t in step-by-step applied for the Maintained Test and Fatigue Cycle Test is conducted. By performing a longitudinal tension experiment, wavelength changes were detected in the center, eye, and splice position of the SMART moorings. The results obtained from each part of the installed sensors indicated a different strain measurement depending on the position of the SMART moorings. The variation of the strain measurement with the position was more than twice the result of the difference measurement, while the applied external load increased step-by-step. It appears that there is a correlation with an externally generated longitudinal tensional force depending on the cross-sectional area of each part of the SMART mooring.

• 한국정보통신학회논문지
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• 제26권2호
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• pp.258-264
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• 2022

정보 통신 기술 (ICT)이 축사와 접목된 스마트 축사는 대부분 클라우드 컴퓨팅 패러다임에 기반하고 있다. 클라우드 기반 스마트 축사는 응답 시간 증가, IoT 센서 증가에 따른 클라우드의 자원 부담, 망의 트래픽 부담과 같은 단점이 있고 인접한 IoT 디바이스와의 협업을 통한 장애 회복 메커니즘이 거의 없는 실정이다. 본 논문에서는 에지 컴퓨팅 기반 IoT 협업 시스템을 제안한다. 에지 디바이스의 비교적 제한적인 컴퓨팅 자원으로 클라우드의 웹 서버 기능을 분담하게 하여 클라우드에 필요한 자원을 절감하며, 사용자 요청에 대한 응답 시간을 개선하고자 한다. 또한 heartbeat 기반 장애 회복 메커니즘을 통하여 IoT 디바이스의 장애를 감지하고 그에 따른 적절한 조치를 하도록 하였다.

• ETRI Journal
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• 제35권4호
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• pp.677-686
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• 2013

In this paper, we first introduce a general architecture of an energy management system in a home area network based on a smart grid. Then, we propose an efficient scheduling method for home power usage. The home gateway (HG) receives the demand response (DR) information indicating the real-time electricity price, which is transferred to an energy management controller (EMC). Referring to the DR, the EMC achieves an optimal power scheduling scheme, which is delivered to each electric appliance by the HG. Accordingly, all appliances in the home operate automatically in the most cost-effective way possible. In our research, to avoid the high peak-to-average ratio (PAR) of power, we combine the real-time pricing model with the inclining block rate model. By adopting this combined pricing model, our proposed power scheduling method effectively reduces both the electricity cost and the PAR, ultimately strengthening the stability of the entire electricity system.

• Smart Structures and Systems
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• 제20권3호
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• pp.263-272
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• 2017

This paper presents the time response of a mixed vibration system with the viscous damping and the hysteretic damping. There are two ways to derive the time response of such a vibration system. One is an analytical method, using the contour integral of complex functions to compute the inverse Fourier transforms. The other is an approximate method in which the analytic functions derived by Hilbert transform are expressed in the state space representation, and only the effective eigenvalues are used to efficiently compute the transient response. The unit impulse responses of the two methods are compared and the change in the damping properties which depend on the viscous and hysteretic damping values is investigated. The results showed that the damping properties of a mixed damping vibration system do not present themselves as a linear combination of damping properties.

• 국제학술발표논문집
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• The 9th International Conference on Construction Engineering and Project Management
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• pp.103-110
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• 2022

In the era of the 4th Industrial Revolution, smart technology being considered to improve productivity breakthroughs is in the spotlight as a means to replace traditional construction technology in the construction industry. However, various problems are occurring in construction sites using smart technology and causing negative impacts on construction projects. Therefore, the objective of this study is to identify risk factors that occur when smart technologies are used in construction projects. To achieve this purpose, this study investigated the difficulties at construction projects using smart technology, and risk factors were derived based on site surveys and literature. The risk factors were measured by experts, and then a total of 19 risk factors was derived by exploratory factor analysis. As a result, risks were classified as 5 factors, the institutional factor is the most difficult response, and the government needs anticipative system improvement and a long-term plan. The research findings provide practical implications for construction experts trying to apply smart technology in construction sites and construction policy-makers to revitalize smart technology.