• Proceedings of the KIEE Conference
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• 2001.10a
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• pp.233-235
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• 2001

On the active filter converter for power factor correction is used inverter for a air-conditioner's power supply to meet IEC standard In the active filter topology for power factor correction, extra switch only control the input current indirectly to satisfied with the IEC standard for reducing the cost and size. In this paper, by dividing the input current into two different modes, the current conduction period can be widened and harmonics can largely be canceled between the two modes. Hence, the harmonics characteristics can be significantly improved, whereby the lower order harmonics, such as the fifth and seventh orders, are much reduced. The results are confirmed by theoretical and experimental implementations.

• Proceedings of the Korean Information Science Society Conference
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• 2000.10b
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• pp.269-271
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• 2000

본 논문에서는 원격지에서 인터넷을 이용하여 가정 내의 가전기기를 제어, 모니터링하는 원격제어 시스템을 설계하고 구현한다. 이때 효율적인 네트워크 이용을 위하여 원격 제어용 프로토콜을 자체적으로 설계하였으며, 이 프로토콜을 통해 지역적으로 멀리 떨어져 있는 가전기기를 제어와 동시에 실시간 모니터링을 할 수 있도록 자바(Java)환경의 소프트웨어를 구현하였다. 또한 본 논문에서는 인터넷을 통해 종류가 같은 가전제품 기기를 한 대 이상 제어 감시할 뿐만 아니라 가정 내에 있는 대부분의 가전기기를 원격 제어하는데 이 시스템을 사용할 수 있다는 가능성을 보였다.

• Proceedings of the Korea Information Processing Society Conference
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• 2022.11a
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• pp.794-796
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• 2022

본 논문은 에어컨 토출구 살균조명용 UV-LED 에 관한 연구이다. 서론에서는 에어컨 토출구에 증식하는 곰팡이의 문제점과 원인에 대해 조사 분석함으로써 연구의 목적을 설명하였다. 본론에서는 내부를 살균하며 동시에 무드조명의 역할을 수행함으로써 얻을 수 있는 장점과 작동방식에 대하여 설명하고, 가능성을 확인하기 위한 실험을 계획하였다. 실험계획과 실험결과에서는 이전 다른 실험과의 차이점과 실험계획을 설명하고, 실험결과에 대해 설명하며 이번 실험에서의 한계점 및 보안할 점도 함께 설명하였다. UV-LED 의 설치 위치를 예시를 들며 설명하였다. 결론에서는 본 논문에서 설명한 연구의 내용을 종합하고, 향후 연구의 진행방향과 추가적으로 필요한 실험 및 적절한 UV-LED 의 파장선택에 대해서 기술하였다.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.10 no.5
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• pp.287-291
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• 2010

In this paper, we designed and implemented mobile object automatic system based on senor networks for telematics. For developing this system, we gather the various sensing data through wireless communication method using zigbee sensor networks and analyze them in monitoring equipment. And we enable the driver to recognize the car state information on the whole by interfacing analyzed data to telematics unit. And, we implemented automatic controller that can control temperature and humidity in car automatically by actuating air conditioner based on the data that was monitored throughout temperature sensor, humidity sensor and brightness sensor based on sensor networks.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.22 no.6
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• pp.7-12
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• 2022

This paper introduces the implementation of the AWS IoT service and MQTT based smart home system. The smart home system implemented in this study can monitor temperature and humidity, and can manually adjust the air conditioner heating, and can check the visitors with the camera and remotely control the door lock. The implemented smart home system controls door locks, heating and air conditioners using Arduino, and manages the collected data and control information using the AWS IoT service. In this study, the Android app has been developed to allow users to control IoT devices remotely, and the MQTT protocol was used for data communication and control between the app and the AWS IoT server and Arduino. The implemented smart home system has been implemented based on AWS IoT service, which has scalability to add sensors and devices.

• Journal of Hydrogen and New Energy
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• v.30 no.4
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• pp.369-375
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• 2019

Air conditioners adopting high energy efficiency and low global warming potential (GWP) refrigerant are being developed globally. In case of commercial air conditioner, R32 with lower GWP than R410A is attracting industrial attentions. In this study, the performance of water-to-water geothermal heat pump adopting R32 is compared with that of the heat pump using R410A. By using R32 instead of R410A, heating capacity and COP in heating standard condition can be increased by 8.8% and 6.3% respectively. Also, cooling capacity and COP in cooling standard condition can be increased by 5.3% and 3.1% respectively by using R32. But in case of using R32, systemic improvements are required to decrease discharge temperature of compressor since discharge temperature rises abnormally in heating operations.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.4
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• pp.212-218
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• 2013

In this paper, a linear motor piston amplitude estimator using phase lag filter has been implemented. In order to control the cooling capability of a refrigerator or an air conditioner in which liner compressors are applied, the piston speed should be controlled. The piston speed control can be obtained by adjusting the frequency or the stroke of linear motors. The dynamic performance of linear compressors depends on how accurately the stroke or the piston amplitude is estimated. A linear motor piston amplitude estimator using phase lag filter is proposed and the superior performance of our estimator is verified via some simulation studies.

• Proceedings of the KIEE Conference
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• 1993.11a
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• pp.19-22
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• 1993

Demand side management (DSM) is the planning and implementation of those utility designed to influence customer use of electricity in ways that will produce desired changes in the utility's load shape. It is conspicuous that the peak load control of DSM is efficiently adopted. In this paper, the package type air conditioner(A/C) mounted radio controlled switch. During the summer of 1990 KEPCO conducted tests in Seoul areas to determine the economic feasibility of interrupting A/C units for short periods of time during peak load periods. These tests were performed between July 30 and September 20 and were limited to the hours of between 1 and 6 p.m. These tests indicated that each A/C contributes approximately 4.5kW to the system peak and can be switched off 10 minutes out of each 1/2 hour without causing the customer any discomfort. Switching each A/C off for 10 minutes out of each 1/2 hour results in a peak load demand reduction of one kW per unit.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.50 no.5
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• pp.238-245
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• 2001

During an AC motor's start-up accelerating period, a large amount of current is required to reach to the rating speed. This is called in-rush current. This peak in-rush current can be more than about several times the operating or steady-state current in the full load rating of the motor. In-rush current is present in both and electronic ballasts. The main area of concern is the tripping of circuit breaker and fuses which can affect electrical system components From this, we can see that the electrical power controllers will be rather concerned, since they have to supply the actual current necessary to start the motor. This paper presents a new method to reducing in-rush current and energy saving of the single-phase induction motor used in air-conditioner. It can be obtained that proposed system is low cost and small size as compared with other controller. Experiments are focused on a capacitor starting single-phase induction motor. The optimal power saving and in-rush current limiting by phase angle control are verified by experimental results. Also, auxiliary winding was controlled by electronic starting switch.

• Journal of Advanced Marine Engineering and Technology
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• v.32 no.5
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• pp.717-723
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• 2008

The purpose of this study is to measure and analyze the indoor thermal conditions of a 8,500GT class chemical carrier which was launched on July 2007. The measurement was operated from 4th June to 4th June 2007, just before handing over to Owner. Followings are the results of this study. (1)The temperature variations of supply air were related to the outdoor temperature variations, but the humidity was stable at $65{\sim}80%$. (2)The temperature variations at the representative position of bridge, restaurant, crew's cabin showed gentle slopes. but that of conference room was very steepy. The humidities of bridge and restaurant were unstable because of outdoor-contact and cooking, respectively. (4)The temperature and humidity of ECR(Engine Control Room) which was designed to supply heating and cooling by PAC(Package Air Conditioner) were directly affected by the operating conditions of PAC. (5)The measured supply air volume from dampers of bridge, crew's cabin and conference room were satisfied with the design supply air volume. (5)For the improvement of the indoor thermal conditions, the temperature of crew's cabin and restaurant and the humidity of conference room, and the temperature and humidity of bridge should be controlled, respectively.