• The Transactions of the Korean Institute of Electrical Engineers B
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• v.52 no.12
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• pp.595-601
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• 2003

For a control of CPS(Contactless Power Supply), the paper deals with the results which are simulated by a equivalent electric circuit on the LIPT(Linear Inductive Power Transmission). In order to control the CPS, the output values is handled with the driving frequency according to the change of a load. The method that controls the driving frequency for adjusting the output power is reasonable to be applied to the controller. But, when the driving frequency meets the resonant frequency and passes, it lead to a serious problem. Therefore, the controlled region of the driving frequency has to be predicted and determined by the simulation of a electric circuit.

• Proceedings of the KIEE Conference
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• 2004.10a
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• pp.218-220
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• 2004

In this paper, the concept of contactless inductive power transfer system used for the PRT system is suggested and some ideas for Power transformer design to improve the power transfer performance are presented. This system has a large air-gap and demands a large electrical power capability But, low output power is generated due to a loosely coupled characteristic of the large air-gap. Therefore, double layer construction of secondary winding, which was divided in half to increase both output current and output voltage was suggested. In addition, the performance of power transformer alignment condition between the primary power line and the power collector was verified by computer simulation of 2kW model.

• Proceedings of the Korean Society of Computer Information Conference
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• 2022.07a
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• pp.485-486
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• 2022

본 논문에서는 OpenCV를 통해 기존의 물리적 버튼 등을 이용한 접촉제어가 아닌 비접촉으로 제어할 수 있는 시스템을 설계하였다. 시스템은 디지털 입력이나 아날로그 입력 등 두 가지 형태로의 모든 입력이 가능하며, 현실 세계에서 사람들이 사용하는 입력 방식과 유사한 방식으로 제어를 하게 함으로써 사용에 대한 기술에 대한 거부감을 줄일 수 있었다. 시스템은 ESP32-CAM 보드와 영상 스트리밍 서버를 FastAPI로 구축해 원격으로 접속과 조작이 가능하도록 설계하였다.

• Clinical and Experimental Reproductive Medicine
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• v.27 no.1
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• pp.39-46
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• 2000

Objective: A number of studies to improve in vitro culture conditions have been tried over past ten years by using co-culture system with helper somatic cells. However, the mechanism of coculture is poorly understood. This study was designed to understand the mechanism for the mode of actual action of co-culture using co-culture system of ICR strain's 1-cell embryos with human oviduct epithelial cells by examining the effect of conditioned medium and contactless coculture using a cell culture insert on the embryo development and by measuring the level of superoxide anion from conditioned medium after co-culture. Methods: ICR strain's zygote embryos were cultured in medium alone (control), coculture, conditioned medium, or contactless coculture system for 6 days. Conditioned media (CM) were prepared as following 5 groups. All CM were collected after culturing oviduct cells for 2 days. CM-1 was stored at $-20^{\circ}C$ until use, and CM-2 was prepared just before use as a culture medium. CM-3 was cocultured with embryos and retrieved just before use. CM-4 and CM-5 were derives from the microfilteration of CM-2 and CM-3, respectively, using Microcon-10 (10 kDa molecular weight cut-off). The percentage of the embryos developed to hatched blastocyst stage and the level of superoxide anion in supernatant from medium alone culture (control), coculture, and contactless coculture were measured. Results: The rates of embryo development to the hatched blastocyst stage were significantly higher in coculture (43%) than in control (0%) (p<0.05). The CM-1 group had no embryo development since 2-cell embryonic stage, whereas the CM-2, CM-3, CM-4 and CM-5 groups had the improved development to 4 or 8 cell embryo stage, but the similar rate of development to hatched blastocyst compared to control. The effect of coculture on embryo development was disappeared in the contactless coculture group. The level of superoxide anion was significantly reduced in coculture group compared to control. Conclusion: It is concluded that the present coculture system overcomes the 2-cell block in vitro and improves the embryo development. This beneficial effect may be due to the direct cell-cell contact between embryo and helper cells or the removal of deleterious components from medium rather than the embryotrophic factors.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.05a
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• pp.1047-1048
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• 2010

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.8
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• pp.1285-1290
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• 2017

In this paper, we developed a core module of the steering system to control and operate the outboard ship with the automatic steering system, and implemented it as a complete integrated system. In particular, this paper presents the problem of the rudder sensor used in the existing system and implements the contactless rudder sensor as an improvement. In the case of existing rudder sensors, there is a problem that safety operation and economic loss of the ship operation is caused by malfunction due to immersion during use in outboard vessels. However, the proposed rudder sensor is separated from the rotary shaft to constitute a contactless type, and a circular magnet is fixed so that the rotating value can be detected and used by the Hall sensor to completely solve the flooding problem. As a result of the characteristic test, the voltage value from 1.8V to 3.2V was obtained between $-35^{\circ}$ and $+35^{\circ}$ degrees and satisfied the reference value. The proposed rudder sensor was mounted on the outboard ship, and all the performance of controller system were checked. According to the system proposed in this paper, it satisfies the Korean Standard Specification, which defines the speed of convergence in 30 seconds by switching from left to right in 7 seconds. We also confirmed that automatic steering was performed by comparing the compass sensor with the destination in the integrated controller at the start-up.

• The Transactions of the Korean Institute of Power Electronics
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• v.14 no.3
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• pp.251-259
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• 2009

In this paper, a contactless power supply using half-bridge series resonant converter that achieves ZVS operation of main switches and ZCS operation of secondary side diodes is proposed. Since the proposed contactless power supply using half-bridge series resonant converter operates with lower switching frequency than the resonant frequency, it can achieve ZCS operation of secondary side diodes due to discontinuous resonant current. And it is also possible to control the converter in narrow frequency range and to obtain high voltage gain, which, in turn, offers low turns ratio for the transformer and high efficiency. Based on the theoretical analysis and simulation results, the 3.15W prototype is built and the final experimental results are described.

• 제어로봇시스템학회:학술대회논문집
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• 1988.10a
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• pp.418-421
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• 1988

Elevator system requires position and speed control at the same time recently. The control device of existing Elevator system making hardware is simplified by using micro-processor that have been developed. In this papers, it consists of contactless logic circuit using miro-processor and digital components. This paper shows that as this system control voltage and frequency using PWM inverter at the same time, speed control is accurate, acceleration and deceleration is soft and passengers can be feel comfortably because speed change is a little during driving.

• Journal of People, Plants, and Environment
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• v.24 no.6
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• pp.595-608
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• 2021

Background and objective: For effective horticultural education, it is required to develop kits for practice. In this study, we developed a horticultural kit for germination that introduces storytelling, characterization, and assembly, and investigated the educational effects of using it to study its educational differentiation and usefulness. Methods: First, we developed a seed germination kit for learning. It consists of three components: the kit main frame for hydroponics, the activity sheet for storytelling, and the instruction manual. It is made into an acrylic assembly in consideration of the ease of delivery for contactless learning. Second, we developed two programs, each using a germination kit for horticultural education (experimental group) and a general germination kit program (control group). At this time, the class consists of pre-questionnaire, the 1st and 2nd classes, observation log writing (total six times for two weeks), the 3rd class, and post-questionnaire. The experimental group and control group were separately executed. Third, the application results were compared and analyzed before and after class. As a quantification questionnaire, the effects before and after class were compared through t-test with a questionnaire on program satisfaction and attitude change toward plants. The quantitative results were analyzed through observation activity sheets and effects before and after the class were analyzed through t-test with quantification and language coding. Results: The effect of horticulture education using the developed kit was estimated by a quantification questionnaire. Both the program satisfaction and the change in attitude toward plants showed high in the experimental group, and this difference was statistically significant (p < .05). As a result of analyzing the observation paper with a qualitative questionnaire, various cognitive and affective expressions appeared in the experimental group as well as the contents of the observation paper. The number of syllables and various qualitative expressions appeared, and these differences were also statistically significant (p < .05). Conclusion: Compared to general germination activities, it was found that the germination activities using storytelling-based horticultural kits would be effective for contactless classes in the post-COVID-19 era and in increasing the educational effect of horticultural activities.

• Proceedings of the KIPE Conference
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• 2000.07a
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• pp.258-261
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• 2000

A non-contact battery charger which transfers energy using magnetic field has a difficulty with a feed-back control due to the interaction between the power and signal processing This paper proposes an effective method which uses auxiliary windings of transformer as signal path and copes with cross-talk using the MOSFET ringing phenomenon and ceramic filter. The power stage is half-bridge series resonant converter. Design procedure and experimental verification are presented.