• 전자공학회논문지A
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• 제33A권6호
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• pp.127-135
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• 1996

To increase the sensitivity and the selectivity of the sensors to TMA gas, the composition ratio and the growth conditions of the ZnO films are studied. Annealing of the ZnO films in the various time ranges and temperatures in the oxygen is carried out to enhance the stbility of the electrical resistance. Pt/Ti heater deposited on backside of the substrates in used to control the operating temperature of th esensor. The ZnO thin film sensors doped to 4.0 wt% $Al_{2}$O$_{3}$ 1.0wt.% TiO$_{2}$ and 0.2wt.% V$_{2}$O$_{5}$ exhibited a high sensitivity and an excellent selectivity for TMA gas. The sensors made with the thin films annealed at 700$^{\circ}$C for 60 minutes in the oxygen atmosphere had a good stability and linearity. The heater deposited in the ratio of 1 to 1 (Pt:Ti) had a good heating properties. The sensors fabricated using above conditions showed a good response to the actual gases of a mackerel at a step of deterioration after death.

• 동력기계공학회지
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• 제19권4호
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• pp.43-49
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• 2015

This study has been analyzed and investigated the possibility for the substitution of a heat source with the application of PTC(Positive Temperature Coefficient Heater) in a food drying machine. And this experiment was conducted to measure temperatures at the upper part of the vessel and the heat sink. And the structure has the many holes plane connected with the external air in the upper part of similar volumetric vessel, and attached to the PTC heater (3sets) of total consumption electricity of 120[W] in Al radiant heat structure and the small fan (2sets) in the suitable space of the lower part. Consequently, it was found that at the most conditions of food drying test with the seven holes(5mm) under the control temperature $62^{\circ}C$, the optimum drying condition formatted and the optimum time range especially appeared from 6,500 second to 7,000 second in case of drying test on banana sample.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2013년도 춘계학술대회
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• pp.904-907
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• 2013

최대전력관리장치는 사용 전력량이 목표 전력량을 초과하는 것으로 예측되면 연결된 부하장치를 차단하여 사용 전력량이 목표 전력량을 초과하지 않도록 제어하는 장치이다. 이러한 ON/OFF 방식을 전기로의 전력 관리에 적용하면 전력을 공급하는 인버터와 전기히터의 기동 및 정지동작이 반복적으로 수행되게 된다. 이는 인버터와 전기히터에 전기적 손상을 가중시켜 수명을 단축시킬 수 있다는 문제점이 있다. 또한 전력 관리에 의해 전력 공급이 차단되었을 때 복귀 시점까지 온도를 조절할 수 없다는 단점이 있다. 본 논문에서는 목표 전력량을 초과하지 않는 범위 내에서 지속적인 전력의 인가를 통해 인버터와 전기히터의 전기적 손상을 방지하고 전기로로 인가되는 전력량을 유기적으로 자동 조절하기 위해 전기로 원격 제어기를 사용한 전력관리 시스템을 개발한다.

• 소성∙가공
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• 제32권3호
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• pp.153-159
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• 2023

This paper presents the optimal design of a heating system using radiant heating elements for application in smart farms. Smart farming, an advanced agricultural technology, is based on artificial intelligence and the internet of things and promotes crop production. Temperature and humidity regulation is critical in smart farms, and thus, a heating system is essential. Radiant heating elements are devices that generate heat using electrical energy. Among other applications, radiant heating elements are used for environmental control and heating in smart farm greenhouses. The performance of these elements is directly related to their electrical energy consumption. Therefore, achieving a balance between efficient electrical energy consumption and maximum heating performance in smart farms is crucial for the optimal design of radiant heating elements. In this study, the size, electrical energy supply, heat generation efficiency, and heating performance of radiant heating elements used in these heating systems were investigated. The effects of the size and electrical energy supply of radiant heating elements on the heating performance were experimentally analyzed. As the radiant heating element size increased, the heat generation efficiency improved, but the electrical energy consumption also increased. In addition, increasing the electrical energy supply improved both the heat generation efficiency and heating performance of the radiant heating elements. Based on these results, a method for determining the optimal size and electrical energy supply of radiant heating elements was proposed, and it reduced the electrical energy consumption while maintaining an appropriate heating performance in smart farms. These research findings are expected to contribute to energy conservation and performance improvement in smart farming.

• 전자공학회논문지S
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• 제35S권10호
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• pp.77-84
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• 1998

기존의 테스트 핸들러는 단일 히터와 팬을 사용하여 항온조내의 IC 테스트점들 사이에 온도 편차가 발생한다. 본 논문에서는 온도 분포가 중간 부분과 가장자리 부분의 온도 오차가 심한 문제에 착안하여, 기존의 히터를 3등분하여 3지점의 온도를 각각 제어함으로써 측정점의 위치에 따라 온도 편차를 줄이는 방안을 제시하였으며, 온도 챔버의 파라미터의 식별과 식별된 모델에 기초하여 LQG 제어기를 설계하였다. 항온조의 온도를 일정하게 유지하기 위하여 RTD 센서와 VME 시스템을 이용하였다. 실험 결과 챔버의 위치에 따른 온도 편차를 50$^{\circ}C$ ${\cdot}$ 80$^{\circ}C$와 120$^{\circ}C$에서 기존의 ${\pm}1.5^{\circ}C$에서 ${\pm}0.35^{\circ}C$로 줄임으로써 그 성능을 개선하였다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1995년도 Proceedings of the Korea Automation Control Conference, 10th (KACC); Seoul, Korea; 23-25 Oct. 1995
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• pp.31-34
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• 1995

The automated chemical analysis shop floor are developed for the environmental pollution problems in our chemical analysis center. This shop floor have the several equipments include weight, pour, dry, heater, boiler, mixture, spectroscopy etc. And the material handling components are made up by the stored stack, conveyore, turntables, robot etc. Computer simulation has been an important tool for these complete design problem. We have designed the arangement of chemical equipments and material flow systems by using the simulator "AutoModII". "AutoMoII" is one of the advanced simulator, CAD-like drawing tools with a powerful, engineering oriented language to model control logic and material flow. The result is the modeling of the chemical analysis system in accurate, three dimensional detail. We could designed the set able layout and scheduling system by using the AutoMoII simulator. AutoMoII simulator.

• 전기학회논문지
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• 제56권11호
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• pp.1921-1924
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• 2007

In order to measure the superconducting transition temperature, the critical current and the alternating current(AC) loss on short samples of high temperature superconductor, a cryocooler cooled cryostat has been designed and built. Two closed-cycle coolers provide cooling with an ultimate sample temperature below 16K. Temperature regulation is provided by 50W of electrical heater that opposes the cooling power from the cold heads. Temperature control feedback is by means of a cernox temperature sensor co-located with the heaters on the second stage of the cold head. Additional temperature sensors are located on the sample mount(B1), on the CVI cold head(B2) and on the Dakin cold head(B3). AC losses on the sample high temperature superconductor were measured at 30K so that the developed device performance was evaluated. In this paper, the design, fabrication and test results on the cryocooler cooled cryostat are presented.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• 제5B권2호
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• pp.181-188
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• 2005

In this paper, a DC smoothing filterless soft switching pulse modulated high frequency AC power conversion circuit connected to utility. frequency AC power source is proposed for consumer induction heating hot water producer, steamer and super heated steamer. The operating principle of DC link filterless utility frequency AC-high frequency AC (HF AC) power conversion circuit defined as high frequency cycloinverter is described, which can operate under a principle of ZVS/AVT and power regulation based on alternate asymmetrical PWM in synchronization with the utility frequency single phase AC positive or negative half wave voltage. The dual mode modulation control scheme based on high frequency PWM and commercial frequency AC voltage PDM for the proposed high frequency cycloinverter are discussed to enlarge its soft switching commutation operating range for wide HF AC power regulation. This high frequency cycloinverter is developed for high frequency IH Dual Packs Heater (DPH) type boiler used in consumer and industrial fluid pipeline systems. Based on the experiment and simulation results, this high frequency cycloinverter is proved to be suitable for the consumer use IH-DPH boiler and hot water producers. The cycloinverter power regulation and power conversion efficiency characteristics are evaluated and discussed.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 심포지엄 논문집 정보 및 제어부문
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• pp.223-224
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• 2008

초초임계압 화력발전 제어계통 설계와 관련하여 보일러 제어시스템의 기본 요건인 제어전략을 구현하기 위해 현재 표준화력 500MW 제어시스템과 제어로직을 기반으로 1000MW급에서 필요로 하는 새로운 구조의 제어에 요구되는 제어전략에 대해 각종 제어 운전 모드의 구성과 각 운전 모드에서의 제어전략을 개발하고 있다. 최신제어시스템에서 중요하게 취급되는 자동 플랜트 제어(Automatic Plant Control, APE)의 각종 제어전략 구성에 중점을 두고 있으며 Unit Master Control, Boiler Master Control, Turbine blaster Control, Throttle Pressure Control, Fuel/Air Master Control, Forced Draft Fan Control, Induced Draft Fan Control, Primary Air Fan, Feed Water Master Control, Super Heater/Reheater Steam Temp Control 등의 제어전략을 논하고, 실제 프로세스 응단특성 파악을 위해 국내 신규발전소를 방문하여 수집한 프로세스 응답시험 결과와 특성을 분석하고 USC에 적용하기위한 보일러 제어전략에 대해 논하고자 한다.

• Smart Structures and Systems
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• 제17권1호
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• pp.135-147
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• 2016

This paper describes a smart structural system, which uses smart materials for real-time monitoring and active control of bolted-joints in steel structures. The goal of this research is to reduce the possibility of failure and the cost of maintenance of steel structures such as bridges, electricity pylons, steel lattice towers and so on. The concept of the smart structural system combines impedance based health monitoring techniques with a shape memory alloy (SMA) washer to restore the tension of the loosened bolt. The impedance-based structural health monitoring (SHM) techniques were used to detect loosened bolts in bolted-joints. By comparing electrical impedance signatures measured from a potentially damage structure with baseline data obtained from the pristine structure, the bolt loosening damage could be detected. An outlier analysis, using generalized extreme value (GEV) distribution, providing optimal decision boundaries, has been carried out for more systematic damage detection. Once the loosening damage was detected in the bolted joint, the external heater, which was bonded to the SMA washer, actuated the washer. Then, the heated SMA washer expanded axially and adjusted the bolt tension to restore the lost torque. Additionally, temperature variation due to the heater was compensated by applying the effective frequency shift (EFS) algorithm to improve the performance of the diagnostic results. An experimental study was conducted by integrating the piezoelectric material based structural health monitoring and the SMA-based active control function on a bolted joint, after which the performance of the smart 'self-monitoring and self-healing bolted joint system' was demonstrated.