• Journal of the Earthquake Engineering Society of Korea
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• v.9 no.1 s.41
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• pp.51-59
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• 2005

Magnetorheological(MR) dampers are one of the most promising semi active control devices, because they have advantages such as small power requirement, reliability, and low price to manufacture. To reduce the responses of structures with MR dampers, a control system including power supply, controller, and sensors is required. However, when a mount of MR dampers are used to a large?scale civil structure such as cable stayed bridges, the control system becomes complex. Therefore, it is not easy to install and maintain the MR damper based control system. To resolve above difficulties, This paper proposes a smart passive system that consists of a MR damper and an electromagnetic induction(EMI) system. According to the Faraday’s law of induction, EMI system that is attached to the MR damper produces electric energy. The produced energy is supplied to the MR damper. Thus, the MR damper with EMI system does not require any power at all. Furthermore, the induced electric energy is proportional to external loads like earthquakes, which means the MR damper with EMI system is adaptable to external loads without any controller and corresponding sensors. Therefore, it is easy to build up and maintain the proposed smart passive system.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.22 no.6
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• pp.842-848
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• 2018

The Smart plug is a device that connects between the outlet and the product at home, and it is an IoT type device that can drive energy saving and transmit information to the outside by power on / off control function and power measurement function. In this case, a smart plug that incorporates deep learning of intelligence technology that allows people to learn how to think about a computer, automatically classifies a product as it operates, and automatically tests the operating status of the washing machine by using input AC current pattern. Through this study, even if the product does not function as IoT, it can classify product type and operation state by smart plug connection alone, so we can draw a new paradigm of life pattern and energy saving in one family.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.19 no.5
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• pp.93-99
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• 2019

In this paper, we propose a smart meter that uses GRU model, which is one of artificial neural networks, for the efficient energy management. We collected power consumption data that train GRU model through the proposed smart meter. The implemented smart meter has automatic power measurement and real-time observation function and load control function through power consumption prediction. We determined a reference value to control the load by using Root Mean Squared Error (RMS), which is one of performance evaluation indexes, with 20% margin. We confirmed that the smart meter with automatic load control increases the efficiency of energy management.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.20 no.9
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• pp.1-10
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• 2021

Recently, the repair and recycling of damaged mechanical parts via metal additive manufacturing processes have been industrial points of interest. This is because the repair and recycling of damaged mechanical parts can reduce energy and resource consumption. The directed energy deposition(DED) process has various advantages such as the possibility of selective deposition, large building space, and a small heat-affected zone. Hence, it is a suitable process for repairing damaged mechanical parts. The shaft is a core component of various mechanical systems. Although there is a high demand for the repair of the shaft, it is difficult to repair with traditional welding processes because of the thermal deformation problem. The objective of this study is to propose a repair procedure for a damaged shaft using the DED process and discuss its applications. Three types of cases, including a small shaft with a damaged surface, a medium-size shaft with a worn bearing joint, and a large shaft with serious damage, were repaired using the proposed procedure. The microstructure and hardness were examined to discuss the characteristics of the repaired component. The efficiency of the repair of the damaged shaft is also discussed.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.26 no.3
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• pp.469-478
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• 2022

This paper contains the results of developing smart devices and applications to monitor the load power of the industrial manufacturing machine and evaluate its performance. The smart devices in this paper are divided into two functionalities, which are collecting load power along with operating environment data of industrial manufacturing machines and transmitting the data to servers. Load power data collected from the smart devices are uploaded to MariaDB inside the Amazon Web Service (AWS) server. Using the RESTFul API, the uploaded power data can be retrieved and shown on the web and mobile application in the form of a graph to provide monitoring capability. To evaluate the performance of the developed system, the response time from MariaDB to web and mobile applications was measured. The results is ranging from 0.0256 to 0.0545 seconds in a 4G (LTE) network environment and from 0.6126 to 1.2978 seconds in a 3G network environment, which is considered a satisfactory result.

• The Journal of the Korea institute of electronic communication sciences
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• v.14 no.3
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• pp.529-536
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• 2019

In order to apply a piezoelectric energy harvester to a smart sensor system, an energy harvest interface circuit including an AC-DC rectifier is required. In this paper, we compared the performance of full bridge rectifier, which is a typical energy harvester interface circuit, and synchronous piezoelectric energy harvest interface circuit by using board-level simulation. As a result, the output power of a synchronous electric charge extraction(: SECE) circuit is about four times larger than that of the full bridge rectifier, and there is little load variation. And a high voltage comparator, which is essential for the SECE circuit for the piezoelectric energy harvester with an output voltage of 40V or more, was designed using 0.35 um BCD process. The SECE circuit using the designed high-voltage comparator proved that the output power is 427 % higher than the FBR circuit.

• 전기의세계
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• v.59 no.9
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• pp.39-45
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• 2010

최근 배전계통에 연계되고 있는 태양광, 풍력발전 등과 같은 신 에너지전원의 용량은 점차 증가하고 있는 상황이지만, 설치자(신 에너지전원 소유자)의 보호방식은 기존 방식을 고수하고 있는 실정으로 신 에너지전원의 역 조류에 의해 설치자의 보호기기(자동화기기 포함)의 오 부 동작 발생 가능성이 커지고 있다. 따라서 본 논문에서는 신 에너지전원이 배전계통에 연계되어 운전되는 경우에 발생 가능한 보호협조의 문제점을 분석하고 이에 대한 대책 방안을 제시한다. 신 에너지전원의 역 조류에 의한 배전계통의 보호협조에 대한 문제점은 크게 3가지로 분류할 수 있는데, 신 에너지전원의 사고전류공급에 의한 보호기기의 정격차단용량(12.5KA)의 상회 가능성과 신 에너지전원의 연계로 인한 임피던스 병렬화로 사고전류의 감소로 발생할 수 있는 분류효과에 의한 보호기기의 부 동작, 연계용변압기의 결선방식에 의한 보호기기의 오동작으로 나눌 수 있다. 여기서는 이에 대한 문제점을 대칭좌표법을 이용하여 구체적으로 해석하고, 이에 대한 최적 운용방안을 제시한다.

• Information and Communications Magazine
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• v.30 no.7
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• pp.58-62
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• 2013

최근에 ICT 기반의 융합 서비스 분야로 인구 밀집지역인 메가 시티에서의 교통, 전력, 상/하수도, u-헬스, 안전/보안등의 문제들을 근본적으로 해결하기 위하여 ICT기반 개방형 플랫폼을 이용한 서비스 인프라 구축 및 개선을 위한 연구들이 많이 진행되고 있다. 이러한 ICT 기반의 융합 인프라 구축 서비스들은 M2M(Machine to Machine)과 D2D(Device to Device)를 기본 연결 수단으로 사용하고 있으며, 이들을 기반으로 서비스 정보 전달 및 제어 정보를 실시간으로 처리하기 위한 IP 기반의 플랫폼이 지원되어야만 융합 서비스가 지속적으로 제공 가능할 것이다. 이들 융합서비스 중에서 전력과 관련하여 한국의 스마트그리드 사업은 기후 변화 대응을 위하여CO2 배출을 줄이고, 에너지 효율을 향상하여 새로운 비즈니스 모델을 만들어 일자리와 신산업을 창출하기 위한 국가 프로젝트로 진행되었다. 그러나, 현재의 전력관련 국내 상황을 살펴보면 여름철과 겨울철에 반복적인 전력 수급 불안으로 인해 피크 전력에 대한 예비력이 부족하여 국가적인 재난인 블랙 아웃의 위기를 걱정하고 있는 실정이다. 본고에서는 한국의 스마트그리드 제주실증단지 사업과 관련하여 현황 및 개선 사항들을 알아보고, 향후 거점지구와 국가 단위의 서비스 확장을 위하여ICT 기반의 개방형 인프라 플랫폼 기술의 중요성을 강조하고자 한다. 이러한 M2M과 D2D를 기반으로 하는 융합 서비스의 성공적인 수행은ICT 기반의 개방형 플랫폼의 우선적인 개발이 필요하며, 플랫폼 기반의 디바이스 보급과 네트워크의 구축이 진행되어야 지속 가능한 융합 서비스를 제공할 수 있을 것이다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.5
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• pp.923-928
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• 2009

The advance of scientific technology is enhanced the effect of reaction. The trend of customer for high function product is enlarged. Thus, the composition of each industry, technology and product is actually happened. Therefore, the fusion of different fields in industrial design is widely accomplished. The example of this fusion effect is that 'ubiquitous or wearable computer' which is combined the function of cloth and computing, which is including any type, any purpose, any telecommunication and any multimedia of cloth inside. The ubiquitous or wearable computer will be a final thing of post pc or next step to pc and internet. This paper is studied for the research of smartware by assistance energy. In this paper, the development of multipurpose smartware(wearable computer) powered by solar energy is introduced.

• Journal of IKEEE
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• v.26 no.3
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• pp.389-395
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• 2022

With the evolution of technology, cyber physical systems (CPSs) are being upgraded, and new types of cyber attacks are being discovered accordingly. There are many forms of cyber attack, and all cyber attacks are made to manipulate the target systems. A representative system among cyber physical systems is a cyber physical power system (CPPS), that is, a smart grid. Smart grid is a new type of power system that provides reliable, safe, and efficient energy transmission and distribution. In this paper, specific types of cyber attacks well known as false data injection attacks targeting state estimation and energy distribution of smart grid, and protection strategies for defense of these attacks and dynamic monitoring for detection are described.