• 한국정보과학회:학술대회논문집
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• 한국정보과학회 2004년도 가을 학술발표논문집 Vol.31 No.2 (2)
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• pp.586-588
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• 2004

가정 내의 가전기기들이 디지털화되고 있고, 이것들을 네트워크로 연결하여 원격지에서 제어하는 스마트 홈 관련 기술들이 현실화되고 있다. 이러한 환경에서의 컴퓨팅을 위해서는 응용 프로그램간의 호환성 뿐 아니라 데이터의 호환성, 그리고 이종의 프로토콜간의 연동이 필수적이다 따라서 이를 위한 소프트웨어가 바로 스마트 홈 미들웨어이다. OSGi(Open Service Gateway Initiative)(8)는 장비 연결 및 제어로 얻을 수 있는 유효한 서비스나 여러 미들웨어들 간의 통합을 위한 제반 환경 제공을 목표로 하는 비 표준화 단체로써 OSGi 프레임워크 환경에서 서비스들은 서비스 게이트웨이와 서비스 번들의 life-cycle을 따라 동적으로 전개된다. 본 저자들은 SMF(Service Management framework)(9)를 사용하여 OSGi를 기반으로 한 Smart Home Service Bundle에 관해서 연구하였다.

• International Journal of Reliability and Applications
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• 제5권1호
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• pp.15-24
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• 2004

Folder type electronic devices have hinge to support the rotational motion of folder. This hinge is stressed by the rotational inertia moment of folder at the maximum open limit position of folder. This stress is repeated whenever the folder is open, and it is a cause of hinge fracture. In this paper, the reliability evaluation for the hinge fracture in the folder type cellular phone is discussed. For this, the durability testing machine using crank-rocker mechanism is developed to evaluate the life cycle of the hinge, and the degradation after repetitions of opening and shutting is evaluated from the deformation around the hinge, where the deformation is measured by ESPI (electronic speckle pattern interferometer). Experimental results showed that ESPI was able to measure the deformation of hinge precisely, so we could monitor the change of deformation around the hinge as the repetition number of folder open is increased.

• International Journal of Automotive Technology
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• 제1권1호
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• pp.17-25
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• 2000

The electromechanical valve train (EMV) technology allows for a reduction in fuel consumption while operating under a stoichiometric air-fuel-ratio and preserves the ability to use conventional exhaust gas aftertreatment technology with a 3-way-catalyst. Compared with an engine with a camshaft-driven valve train, the variable valve timing concept makes possible an additional optimization of cold start, warm-up and transient operation. In contrast with the conventionally throttled engine, optimized control of load and in-cylinder gas movement can be used for each individual cylinder and engine cycle. A load control strategy using a "Late Intake Valve Open" (LIO) provides a reduction in start-up HC emissions of approximately 60%. Due to reduced wall-wetting, the LIO control strategy improves the transition from start to idle. "Late Exhaust Valve Open" (LEO) timing during the exhaust stroke leads to exhaust gas afterburning and, thereby, results in high exhaust gas temperatures and low HC emissions. Vehicle investigations have demonstrated an improved accuracy of the air-fuel-ratio during transient operation. Results in the New European Driving Cycle have confirmed a reduction in fuel consumption of more than 15％ while meeting EURO IV emission limits.

• 한국정밀공학회지
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• 제19권11호
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• pp.221-227
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• 2002

Tapping is a machining process that makes a female screw on parts to be assembly together. Recently, as the number of small and compact products increases the radius of tap as small as 1 mm is not unusual and more accurate tapping is needed. In complying with those needs, some high-speed tapping machines with synchronizing function have been developed. This paper describes the development of an ultra high-speed tapping machine up to 10,000rpm. The key factors in the tapping speed are the acceleration/deceleration and the synchronizing errors between spindle motor and fred motor. To minimize the acceleration/deceleration time, a low inertia spindle with a synchronous built-in servo motor was developed. To minimize the synchronizing errors, the tapping cycle algorithm was optimized on an open architecture CNC. The developed tapping machine has the acceleration/deceleration time of 0.13sec/10,000rpm for rigid tapping and the synchronizing error below 4.4%. The cycle time for tapping a female screw of M3 and depth 2 times diameter was 0.55sec.

• 한국추진공학회지
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• 제15권1호
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• pp.45-54
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• 2011

액체로켓엔진 시스템에 대한 동특성 예측 프로그램을 작성하였다. 이 프로그램을 통해 얻은 펌프 시동 시 압력 및 유량 변화 결과를 수류시험장치를 구축하여 실험적으로 검증하였다. 수류시험장치는 실제 개방형 액체로켓엔진 추진제 공급 계통에서 구성품의 형태와 배치위치, 가스발생기와 주연소실로 분기되는 유량비를 기준으로 모사되었다. 동특성 예측 프로그램의 작성을 위해 구성품별 동특성 모델링을 수행하고 엔진 시스템을 기준으로 각 모델링을 순차적으로 통합하였다. 예측 프로그램에 구성품의 동특성 파라미터를 측정 반영하였고 천이 작동 상태에서 엔진 시스템 내의 작동 파라미터 변화 결과를 실험적으로 측정하고 비교 분석하였다.

• 통상정보연구
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• 제15권2호
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• pp.163-185
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• 2013

본 논문은 한국항공주식회사 분사기업과 비분사기업의 구별에 따른 한국 항공 중소기업들이 개방형혁신 특성을 개별사례를 중심으로 분석하고 있다. 한국항공주식회사 분사기업 여부에 따른 항공 중소기업들의 개방형 혁신 특성이 차이가 나는가? 그렇다면 구체적으로 어떠한 차이가 존재하는가? 하는 연구문제에 대한 답을 구하고 있다. 특히 한국 항공산업 클러스터의 대표지역인 사천지역의 항공 중소기업들에 대한 심층 인터뷰를 통해서 연구문제에 대한 답을 구한다.

• 한국주거학회논문집
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• 제13권5호
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• pp.51-58
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• 2002

The purpose of this study is to examine residents' perception and needs for storage according to the family life cycle. In order to achieve our goal, the questionnaire survey is used. We sample the questionnaire surveys of 250 apartment households in Seoul. The data collect by the questionnaire survey was analyzed by examining the frequency, percentage on the SPSS/PC+ Statistics package. The results of the study are obtained as follows: 1) In research on the actual storage condition, residents tend to feel constraint on storage of the season goods and the storage satisfaction on the service area is founded lowest. Therefore, it is needed more efficient space plan on the balcony storage and the interior storage for the season goods. 2) In research on the storage consciousness and attitude, residents tend to keep the goods of no use and prefer to arrange neatly rather than use conveniently. Therefore, it is needed more efficient space in the balcony for the storage of the goods of no use and the colsed furniture rather than the open furniture is suited for arrangement. 3) In research on the storage needs, needs for the built-in furniture in all family life cycle show highly and residents want to a space for the exclusive use of the storage. In a solution, we propose to equip with the interior storage and the exterior cooperative storage

• 설비공학논문집
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• 제26권11호
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• pp.504-511
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• 2014

The objective of this study is to theoretically analyze the performance of an open wet air-cycle refrigeration system, which nowadays is increasingly generating environmental concern. The temperature and relative humidity of the outside air are selected as the most important parameters. As the temperature and relative humidity of the outside air increase, the pressure ratio of the ACM compressor is determined to be nearly constant, the air temperature at the exit of the system increases, and the amount of condensed water, the cooling capacity, the COP, and the total entropy production rate increase overall. The effects of the effectiveness of the heat exchanger and the efficiency of the turbine on the performance are greater than that of the efficiency of the ACM compressor. Also, the performance of the wet air-cycle refrigeration system with two heat exchangers is enhanced, with a high COP and low total entropy production rate, compared to the system with a single heat exchanger.

• 한국표면공학회지
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• 제39권6호
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• pp.302-311
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• 2006

Nowadays the open-type lead-acid battery for vehicle use is being replaced with the sealed-type because it needs no maintenance and has a longer cycle life. Thus researches on this battery are being conducted very actively by many advanced battery companies. There is, however, a serious problem with the maintenance free(MF) battery that its cathode electrode has a limited cycle life due to a corrosion of grid. In this study, it was aimed to improve a corrosion resistance of the cathode grid which is commonly made of Pb-Ca alloy for a mechanical strength. For this purpose, various amounts of alloying elements such as Sn, Ag and Ba were added singly or together to the Pb-Ca alloys and investigated their corrosion behaviors. Batteries fabricated by using these alloys as cathode grids were subjected to life cycle test and their corrosion layers appeared at the interface between the grids and the active materials were carefully observed in order to clarify effects of alloying elements.

• Journal of Computing Science and Engineering
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• 제2권3호
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• pp.249-273
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• 2008

Epidemic protocols have two fundamental assumptions. One is the availability of a mechanism that provides each node with a set of log(N) (fanout) nodes to gossip with at each cycle. The other is that the network size N is known to all member nodes. While it may be trivial to support these assumptions in small systems, it is a challenge to realize them in large open dynamic systems, such as peer-to-peer (P2P) systems. Technically, since the most fundamental parameter of epidemic protocols is log(N), without knowing the system size, the protocols will be limited. Further, since the network churn, frequently observed in P2P systems, causes rapid membership changes, providing a different set of log(N) at each cycle is a difficult problem. In order to support the assumptions, the fanout nodes should be selected randomly and uniformly from the entire membership. This paper investigates one possible solution which addresses both problems; providing at each cycle a different set of log(N) nodes selected randomly and uniformly from the entire network under churn, and estimating the dynamic network size in the number of nodes. This solution improves the previously developed distributed algorithm called Shuffle to deal with churn, and utilizes the Shuffle infrastructure to estimate the dynamic network size. The effectiveness of the proposed solution is evaluated by simulation. According to the simulation results, the proposed algorithms successfully handle network churn in providing random log(N0 fanout nodes, and practically and accurately estimate the network size. Overall, this work provides insights in designing epidemic protocols for large scale open dynamic systems, where the protocols behave autonomically.