• 드라이브 ㆍ 컨트롤
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• 제11권3호
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• pp.47-54
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• 2014

Clutches are an integral part of the automatic transmission for changing gears. Modern automatic transmissions make extensive use of wet multiple-disc clutches employing hydraulic actuation mechanism with electronic control. Although nowadays, highly advanced shifting algorithm implements the superior shift quality and transmission efficiency, its performance should be based on smooth, reliable engagement with a reasonably durable friction material as well as stable clutch piston dynamics. Particularly, clutch filling control is the crucial part of shifting process because only the open-loop control is available due to the lack of measurement. In this paper, the effect of clutch-fill control parameters on clutch piston dynamics is experimentally investigated by using clutch piston test equipment which enables the clutch piston to actuate similar to real shifting conditions. The experimental analysis results can be expected to be utilized for the calibration of proportional solenoid valve as reference current profile data in vehicle test.

• Tribology and Lubricants
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• 제21권5호
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• pp.227-235
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• 2005

This paper presents a tribological study on the failure cases of automatic transmission components in a passenger car. The automatic transmission system is composed of torque converter, clutch, brake, planetary gear, and valve body controlling oil pressure of an automatic transmission fluid. The most largest influence components in an automatic transmission are a torque converter and clutch plate in which are influenced by a wear and torque converting energy loss. The failure case study of an automatic transmission indicates that the tribological design and maintenance technologies should be considered as a key design concept. This means that the failure and power energy loss come from the friction, wear and a oil leakage of an automatic transmission, which is related to the oil seal and O-ring seal failures.

• 한국정보통신학회논문지
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• 제7권5호
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• pp.1026-1031
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• 2003

자동 급수펌프는 압력스위치에 의해 운전 및 정지를 하게 된다. 따라서 수량 증감에 따른 펌프의 빈번한 운전 및 정지로 인해 지속적인 정격 및 정압 운전이 불가능하다. 또한 빈번한 작동으로 인해 지속적으로 일정한 압력을 얻을 수 없으며, 펌프의 소손과 에너지의 낭비가 심한 단점을 가지고 있다. 본 논문에서는 이러한 단점을 해결하고자 급수밸브, 유량센서, 제어장치로 구성되는 정압 급수장치를 설계 제작하였다. 급수밸브는 유출되는 물의 양과 관계없이 항상 일정한 양의 물을 유입하여 펌프의 부하를 줄이는 역할을 한다. 유량센서는 적외선 다이오드를 사용하여 유출되는 물의 양의 측정하며, 제어장치는 8 비트 마이크로프로세서를 이용하여 설계하였으며, 특별한 제어 알고리듬에 의해 펌프의 운전과 정지를 제어하게 하였다. 본 논문에서 개발한 장치는 토출 압력이 일정하게 유지되고 펌프의 작동 및 정지 동작이 부드럽게 이루어지며, 펌프의 지속적인 정압운전이 가능하므로 기존의 단점을 보완하는 장치로 사료된다.

• 오토저널
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• 제14권4호
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• pp.79-89
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• 1992

The behavior of belt tension in OHC drive timing belt system was investigated analytically and experimentally for (1)fixed and (2)automatic tensioner. From the numerical results it was found that the automatic tensioner makes the belt tension larger than those of the fixed tensioner. When the initial belt tension decreased due to the belt elongation, the belt tension of the fixed tensioner could decrease to near zero while the belt tension for the automatic tensioner maintained above zero by the tensioner spring. The mean valve and the difference between the maximum and the minimum belt tension for the automatic tensioner increased compared with those of the fixed tensioner. Also, the numerical results for a hydraulic tensioner showed that the hydraulic tensioner has the good parts of both tensioners; i.e., thesmaller amplitude in belt tension and the higher mean tension. Experimental results for the automatic and fixed tensioner of the OHC timing belt system were in agreement with the theoretical results.

• 문화기술의 융합
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• 제5권3호
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• pp.351-357
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• 2019

이 연구는 습식, 건식, 준비작동식, 부압식, 일제살수식 등 각각의 스프링클러설비의 주요 구성요소인 알람체크밸브, 건식밸브, 준비작동식밸브, 일제개방밸브를 전자개방밸브로 대체하여 제조공정의 다양한 과정을 하나의 과정으로 단순화시켜서 단일 기계에서 규격화 된 하나의 제품을 동시에 생산할 수 있는 환경을 조성하여 제품의 가격경쟁력 향상, 제고유지 비용 절감 및 향후 새로이 개발되는 스프링클러설비에도 적응성이 용이하도록 하기 위한 것이다. 기존 스프링클러설비의 종류인 습식, 건식, 준비작동식, 부압식, 일제살수식 모두 1차측과 2차측 배관을 제어하기 위한 밸브만 교체하고 리타딩체임버, 자동식 공기압축기, 엑셀러레이터 또는 익져스터, 슈퍼바이조리패널, 진공펌프, 수동기동장치 등 그 밖의 구성요소는 그대로 사용하기 때문에 기존 스프링클러설비에 쉽게 적용할 수 있다는 장점이 있다. 향후 연구과제로 전자개방밸브를 적용한 스프링클러설비의 상용화를 위한 법적 및 제도적인 연구가 필요하다.

• Journal of Biosystems Engineering
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• 제11권1호
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• pp.31-36
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• 1986

As a part of study on automatic control system for green houses, an automatic irrigation system was developed by using microcomputer. For the study, gypsum block was used as a sensing device of soil moisture and its data was designed to transfer to microcomputer through A/D converter. Also, software which be able to control the irrigation time and flow rate by the solenoid valve was developed. This system was tested by using practical data and the following results were summarized. 1. Since the gypsum was very accurate in addition with chiep and easy to manufacture, it turned out to be a very good device to detect the soil moisture in this system. 2. Also, solenoid valve was very excellent device for controlling the water flow rate since its control error is less then 1% when the irrigation time is over 100 seconds.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 1995년도 춘계학술대회 논문집
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• pp.34-39
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• 1995

To reduce the shock in shifting the clutches and the brakes in automatic transmission have to be connected smoothly and disconnected rapidly. It is PCSV(Pressure Control Solenoid Valve) that play this role of automatic transmission. In this paper there were two steps in the analysis of the PCSV. The first step was modeling the elctromagnet by the permeance method. The second step was modeling the hydraulic circuit by the pressure differential equation. In addition to this modeling a experiment was performed and the commercial package program was used in order to justify modeling. The result of modeling coincide with the result of experiment and commercial package program. As a result this modeling is usable in analysis of dynamic characteractic of the PCSV.

• 한국지열·수열에너지학회논문집
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• 제17권3호
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• pp.1-12
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• 2021

In this study, the effects of various operational conditions for floor radiant heating system were researched by experiments. Hot water supply set temperature, indoor air set temperature and supply water flowrate were considered as operational conditions. The control method for this system is On-Off control of automatic thermostatic valve. The purpose of this study is to evaluate indoor thermal control characteristics and energy performance, respectively. As a result, if lower supply water temperature is applied, the supply and return temperature difference is reduced and energy consumption of heat supply is also reduced.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 1995년도 특별강연 및 춘계학술발표 개요집
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• pp.118-122
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• 1995

The hydraulic or pneumatic valve spools become essential as the important components on the production of automatic hydraulic or pneumatic machinaries as mechanical industry is developed rapidly. The machining precision is asked for manufacturing the valve spools. They could be unstable in the quality by the conventional arc welding and they have a lot of technical problems in manufacturing because their shapes are generally small. By the Precision casting process such as lost wax process, the production cost will be increased. But by the friction welding technique, they will be able to be made without such problems. Furthermore, there is a few study on friction welding of such hydraulic valve spool steels and in-process real-time weld quality evaluation technique by acoustic emission. So that, the final purpose of this study is 1) the development of design and manufacturing technique of hydraulic or pneumatic valve spool by optimizing of friction welding, and 2) the development of in-process real-time weld quality evaluation technique by acoustic emission.

• 문화기술의 융합
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• 제5권3호
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• pp.125-130
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• 2019

2019년 하노이에서 열린 체 2차 북미회담은 공동 합의를 도출하지 못한 채 결렬되었다. 본 논문은 마틴과 화이트(2005)의 평가어 체계를 근간으로 총 8개의 사설들, 구체적으로는 4개의 주요 미국 언론들의 사설들과 4개의 한국 언론들의 사설들을 평가어들을 포함한 언어적 표현들을 중심으로 분석하였다. 분석 결과 뉴욕타임즈, USA투데이, 워싱턴 포스트, 월스트리트 저널의 사설들 중 월스트리트 저널을 제외한 3개의 언론들은 모두 회담 결렬의 원인을 트럼프 대통령 개인으로 귀속시키며 부정적 평가어로 입장을 전달함을 알 수 있었다. 그러나 4개의 신문 사설에서는 한반도의 비핵화나 평화에 대한 우려에 대한 내용을 담고 있지 않았다. 반면 한국의 언론들은 모두 회담 결렬의 원인보다는 향후 방향에 대해 중점을 두고 있었는데, 두 언론은 부정적 행위평가어를 이용하여 문제점과 우려를 제기했지만, 다른 두 언론은 한겨레신문과 경향신문은 향후 대응과 입장에 중심을 두었고 부정적 평가어보다는 당부와 조언의 언어적 자원을 활용하고 있음이 밝혀졌다. 이를 통해, 담론 소비에 있어 양국의 언론들은 각자의 입장을 전달하는 데 있어 부정적인 평가어를 선호한다는 점, 그리고 기대와 당부를 전달할 때는 평가어보다는 보조 용언과 같은 언어적 표현을 사용한다는 것을 알 수 있었다.