• 전기전자학회논문지
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• 제24권3호
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• pp.713-718
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• 2020

피부 활성점(경혈) 측정 방법은 편리성, 저비용 및 비 침습으로 측정하기 때문에 많은 생체정보를 얻기 위한 기술이다. 본 연구에서는 피부 아래에 활성점을 측정할 수 있는 장점이 있는 3전극 측정방법을 사용되었다. 임피던스측정방법은 측정실험 결과와 관련성이 있는 등가전기회로를 통해서 증명되었다. 활성점의 특성주파수는 주변 피부보다 15-30Hz 높고, 리액턴스는 35-77kΩ 더 작게 측정되었다. 이 기술은 비침습 측정 시스템을 이용해서 활성점과 주변피부의 리액턴스와 특성주파수를 정확하고 객관적으로 분석되었다.

• Earthquakes and Structures
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• 제11권2호
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• pp.347-369
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• 2016

The main objective of this paper is the robust multi-objective optimization design of semi-active tuned mass damper (STMD) system using genetic algorithms and fuzzy logic. For optimal design of this system, it is required that the uncertainties which may exist in the system be taken into account. This consideration is performed through the robust design optimization (RDO) procedure. To evaluate the optimal values of the design parameters, three non-commensurable objective functions namely: normalized values of the maximum displacement, velocity, and acceleration of each story level are considered to minimize simultaneously. For this purpose, a fast and elitist non-dominated sorting genetic algorithm (NSGA-II) approach is used to find a set of Pareto-optimal solutions. The torsional effects due to irregularities of the building and/or unsymmetrical placements of the dampers are taken into account through the 3-D modeling of the building. Finally, the comparison of the results shows that the probabilistic robust STMD system is capable of providing a reduction of about 52%, 42.5%, and 37.24% on the maximum displacement, velocity, and acceleration of the building top story, respectively.

• 전자공학회논문지SC
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• 제42권5호
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• pp.1-12
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• 2005

이동로봇과 작업로봇의 직결연결 형태인 이동매니퓰레이터는 원자로 내부와 같은 위험한 작업환경에서 다양한 일한 처리하기위해 유용한 시스템이라 할 수 있다. 하부의 이동로봇은 non-holonomic 시스템이고 상부의 작업로봇의 결합으로 인하여 기구학적 잉여자유도를 갖고 있다. 그러나 주행 중 작업공간 확보로 인하여 고정식 매니퓰레이터보다 더 효율적인 작업이 가능 하다고 할 수 있다. 본 논문에서는 영상정보에 의한 물체인식 및 최적주행을 수행하기 위하여 이동로봇에 장착된 능동카메라에 인식된 영상과 실제 물체간의 기하학적 관계를 이용하여 직교좌표상의 물체의 위치를 추정할 수 있도록 하였다. 두 번째로 시스템의 위치변위 및 영상정보를 이용하여 물체위치를 추정하고 동차행렬을 이용하여 이동매니퓰레이터의 현 위치와 물체간의 최적경로를 결정하는 방법을 제시하였다. 제시한 방법을 시뮬레이션과 이동매니퓰레이터를 이용한 실험데이터분석을 통하여 유효성을 제시하였다.

• Journal of Power Electronics
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• 제16권2호
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• pp.760-768
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• 2016

Three-phase grid-connected inverters are widely applied in the fields of new energy power generation, electric vehicles and so on. Islanding detection is necessary to ensure the stability and safety of such systems. In this paper, feature recognition technology is applied and a novel islanding detection method is proposed. It can identify the features of inverter systems. The theoretical values of these features are defined as codebooks. The difference between the actual value of a feature and the codebook is defined as the quantizing distortion. When islanding happens, the sum of the quantizing distortions exceeds the threshold value. Thus, islanding can be detected. The non-detection zone can be avoided by choosing reasonable features. To accelerate the speed of detection and to avoid miscalculation, an active islanding detection method based on feature recognition technology is given. Compared to the active frequency or phase drift methods, the proposed active method can reduce the distortion of grid-current when the inverter works normally. The principles of the islanding detection method based on the feature recognition technology and the improved active method are both analyzed in detail. An 18 kVA DSP-based three-phase inverter with the SVPWM control strategy has been established and tested. Simulation and experimental results verify the theoretical analysis.

• 보건행정학회지
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• 제20권2호
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• pp.104-127
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• 2010

To vitalize the link program of Korean long-term care insurance system to community-based services for non-eligible people, we analysed the claim data from the Korean National Health Insurance Corporation (NHIC), and conducted a questionnaire survey to charging employees of elderly service department at local governments. The subjects were all 81,377 people, 57,454 of them were arranged to community-based services. The link program was more necessary among the missed subjects rather than the arranged people due to the need for physical or psychological assistance. By the result of the survey to the local government employees, 59.5% of subjects responded their proportion of link service was over 10% and under 20%, and 54.3% of them responded their job boundary are not clear. Major type of linking was notification the subject list to local government, 91.4%; proportion of periodical notification on the status of their service link were 57.1%, only 7.1% were followed to manage after the link. Difficult factors at the link process were pointed out the overload by other side work, deficiency of resources, rigidity of priority of link, and so on. Considering these results, to vitalize the community-based services to the non-eligible people, it may be essential the active participation of the subjects, construction of parts working in coordination among the institutions including NHIC, local governments, and service providers; development of various services for maintenance or promotion of the non-eligible peoples' health and functional status; and active participation of institutions from the third sector, and so on.

• Journal of electromagnetic engineering and science
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• 제17권3호
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• pp.126-132
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• 2017

In this study, we designed, measured, and analyzed a rearranged L-shape magnetic resonance coupling wireless power transfer (MR-WPT) system for practical applications with laptops. The typical four resonator MR-WPT (Tx part: source loop and Tx coil; Rx part: Rx coil and load loop) is difficult to apply to small-sized stationary and mobile applications, such as laptop computers, tablet-PCs, and smartphones, owing to the large volume of the Rx part and the spatial restrictions of the Tx and Rx coils. Therefore, an L-shape structure, which is the orthogonal arrangement of the Tx and Rx parts, is proposed for indoor environment applications, such as at an L-shaped wall or desk. The relatively large Tx part and Rx coil can be installed in the wall and the desk, respectively, while the load loop is embedded in the small stationary or mobile devices. The transfer efficiency (TE) of the proposed system was measured according to the transfer distance (TD) and the misaligned locations of the load loop. In addition, we measured the TE in the active/non-active state and monitor-open/closed state of the laptop computer. The overall highest TE of the L-shape MR-WPT was 61.43% at 45 cm TD, and the TE decreased to 27.9% in the active and monitor-open state of the laptop computer. The conductive ground plane has a much higher impact on the performance when compared to the impact of the active/non-active states. We verified the characteristics and practical benefits of the proposed L-shape MR-WPT compared to the typical MR-WPT for applications to L-shaped corners.

• Journal of information and communication convergence engineering
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• 제5권4호
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• pp.369-373
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• 2007

RFID systems large volume of data, it can lead to slower queries. To achieve better query performance, we can partition into active and some nonactive data. In this paper, we propose two approaches of partitioning for efficient query support. The one is average period plus delta partition and the other is adaptive average period partition. We also present the system architecture to manage active data and non-active data and logical database schema. The data manager check the active partition and move all objects from the active store to an archive store associated with an average period plus data and an adaptive average period. Our experiments show the performance of our partitioning methods.

• 한국철도학회논문집
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• 제7권3호
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• pp.173-179
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• 2004

This paper describes a low-cost single-phase active power filter, which consists of a half-bridge PWM inverter with a simple control circuit. In order to verify the performance of proposed active power filter, many computer simulations with EMTP codes and experimental works with a hardware prototype were done. Both results confirm that the proposed active power filter shows excellent performance to eliminate the harmonics generated in the single-phase non-linear load. The active power filter has advantage of low implementation cost and compact size, using a half-bridge inverter and a simple control circuit with only one current sensor. So, it can be fabricated as a plug-in type. This paper shows the necessity and a good possibility to apply such advantage to the electric railway system.

• 한국정보통신학회논문지
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• 제17권1호
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• pp.127-136
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• 2013

계통연계형 인버터의 중요 성능 중 단독운전 검출기능 및 방지기능은 계통을 유지보수하기 위한 작업자의 안전을 위하여 고려되어야 할 필수 사항이다. 본 논문에서는 태양광을 이용한 계통연계형 태양광발전시스템에서의 AFS(Active Frequency Shake) 단독운전 검출기법을 제안하고자 한다. 먼저 AFS 단독운전 검출 알고리즘을 제안하기 위하여 기존의 능동 주파수 변이기법 알고리즘에 대해 기술한다. 그리고 단독운전 불검출영역을 줄이고, THD(Total Harmonic Distortion)를 개선하며, 기존 알고리즘 보다 검출 속도 또한 향상 시킬 수 있는 알고리즘을 제시하였다. 아울러 제안된 단독운전방지 기법을 3kW 계통연계형 태양광 인버터에 적용하고 시뮬레이션 및 실험을 통하여 제안하는 알고리즘의 타당성을 검증하였다.

• 한국정밀공학회지
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• 제18권3호
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• pp.115-121
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• 2001

In micro automation technology, the concurrent realization of a high resolution and a large operating rage has been achieved by a dual actuator, usually called by piggy-back system, conventionally. But, because of its manufacturing cost, the complexity of control, and the limit of overall bandwidth, the contract-free and single servo actuators have been suggested with specific applications. In this paper, we suggest a novel non-contact surface actuator suing combination of the Lorentz force and the magnetized force, and discuss the actuating principles including an analytical approach. Differently from the existing planar system, an operating range of the suggested system can be expanded by an additional attachment of active elements. Therefore, it is estimated to be suitable for the next-generation moving system.