• 한국정보과학회논문지:데이타베이스
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• 제33권7호
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• pp.715-726
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• 2006

웹 서비스는 인터넷 상에 분산되어 있는 이질적인 응용들 사이의 연동 및 통합을 위한 표준화된 수단을 제공한다. 본 논문에서는 계층적인 연동 관계가 존재하는 복합 웹 서비스들에 대해 서비스 결과로 전달되는 내포 데이타를 활용하여 웹 서비스들의 호출 및 복귀 작업을 서버 및 통신 비용에 따라 효과적으로 분산 수행함으로써 웹 서비스 시스템의 전체적인 성능을 향상시킬 수 있는 방안을 제시한다. 본 논문에서는 내포 결과를 이용한 적법한 웹 서비스 호출 실행 계획 및 이에 대한 비용 기반 최적화 문제를 정의하고, 최적 호출 실행 계획을 찾기 위한 휴리스틱 탐색 방법과 효율적으로 수행될 수 있는 그리디 알고리즘을 제안한다. 실험 결과, 제안한 그리디 알고리즘은 빠른 시간 내에 최적 해에 가까운 효율적인 호출 실행 계획을 생성하며, 복잡한 웹 서비스 연동 관계에 대해서 우수한 확장성을 보였다.

• Journal of Electrical Engineering and Technology
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• 제11권1호
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• pp.117-124
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• 2016

Solar photovoltaic pumping system is one of most important of renewable energy applications especially in rural areas. Besides, the control strategy for standalone solar pumping system based on induction motor and without DC/DC converter has been widely studied and discussed in the literature. This topology is of great concern due its economic issues, especially when a standard frequency converter (SFCs) with scalar control is used instead of a dedicated PV inverter. This paper proposes an external control module to generate SFCs frequency reference in order to ensure both maximum power point tracking (MPPT). We present method of modeling and control of photovoltaic pumping system based centrifugal pump controlled by new improved incremental conductance in order to optimize the price and operation of pumping system this MPPT algorithm have many advantages like can be eliminate proportional integral controller It is a low cost solution since it requires no additional power equipment. The induction motor driven pump that is powered by a solar array is controlled by the indirect field oriented control (IFOC). The effectiveness of the proposed approach is illustrated by simulations carried out under Matlab Software. The experimental results are compared with simulation results.

• KIEAE Journal
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• 제16권1호
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• pp.29-36
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• 2016

Purpose: The purpose of this study is to present basic data which would be applied on the early stage of the architectural design. And that determines the introduction of the atrium by comparing and analysing the environmental performance of atrium building. Method: The building forms are classified into low storied building, middle storied building and high storied building. This study compares and analyses energy performance of the standard building without atrium and the atrium building which has one-side, two-side, three-side, four-side, and linear atrium by measuring of annual heating and cooling load with EnergyPlus. Result: As a result of the analysis of the relative annual heating and cooling load by building type, it is shown that the fluctuation of cooling load in low storied building is large because heat storage in atrium affects building, and the fluctuation of heating load in high storied building is large owing to the effect of external wall area of atrium which makes heat loss. Especially, it indicated the largest annual heating and cooling load in four-side atrium of low storied building, and in one-side atrium of high storied building.

• 한국광학회지
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• 제15권2호
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• pp.177-182
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• 2004

우리는 외부공진분광법을 이용하여 $^{13}$C$_2$H$_2$ 분자의 회전-진동전이의 V$_1$＋V$_3$ 밴드 P(16)전이선의 포화흡수신호를 관측하고, 이 포화 흡수 스펙트럼을 이용하여 1550 nm 영역에서 반도체 레이저 주파수 안정화를 수행하였다. 측정된 포화흡수 스펙트럼의 크기는 선형 흡수에 대해서 약 7%이고, 선폭은 약 1.8 MHz로 측정되었다. 반도체 레이저 주파수를 $^{13}$C$_2$H$_2$ 분자P(16) 전이선에 안정화했을 때 안정화된 레이저의 상대주파수 흔들림은 게이트 시간 0.1 s에서 약 $\pm$20 KHz로 측정되었다.

• Smart Structures and Systems
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• 제17권5호
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• pp.753-771
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• 2016

This paper addresses the free and transient responses of a SDOF linear complex stiffness system by making use of the Hilbert transform and the convolution integral. Because the second-order differential equation of motion having the complex stiffness give rise to the conjugate complex eigen values, its time-domain analysis using the standard time integration scheme suffers from the numerical instability and divergence. In order to overcome this problem, the transient response of the linear complex stiffness system is obtained by the convolution integral of a green function which corresponds to the unit-impulse free vibration response of the complex system. The damped free vibration of the complex system is theoretically derived by making use of the state-space formulation and the Hilbert transform. The convolution integral is implemented by piecewise-linearly interpolating the external force and by superimposing the transient responses of discretized piecewise impulse forces. The numerical experiments are carried out to verify the proposed time-domain analysis method, and the correlation between the real and imaginary parts in the free and transient responses is also investigated.

• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2012년도 춘계학술발표대회 논문집
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• pp.337-344
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• 2012

Today, the number of super tall buildings are under construction or being planed in Middle East and Asian Countries. For example the burj Khalifa, the tallest building in the world, is completed in 2008 and the height of that is about 800m. Also, Lotte World Tower is under construction in Korea. External environmental conditions such as wind speed, air temperature, humidity and solar radiation around the super tall building differs according to the building height due to the vertical micro climate change. However, the meteorological information used for AC design of building is obtained typically from standard surface meterological station data(~2m above the ground). In this paper the effect of the building envelope on heating and cooling load in super tall building considering the meteorological changes with height was analyzed with simulation method. As results of this research, the guideline to select the building envelop alternatives for super tall building will be suggested in this paper.

• 한국통신학회논문지
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• 제27권1C호
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• pp.36-47
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• 2002

MGCP는 IETF에서 제안한 VoIP기술의 표준 프로토콜로서 다른 프로토콜과의 연동이 용이하도록 설계되었으며, 현재 다양한 이기종 시스템과 프로토콜로 구성되어 있는 망을 통합하기 위한 적절한 해결책으로 부각되고 있다. 본 논문에서는 MGCP 호 제어를 담당하는 외부 시스템(MGC)으로부터 VoIP 게이트웨이를 제어하기 위해 사용된다. 또한 MGCP기반의 다양한 게이트웨이 시스템에서 다양한 MGC에 대해 호환성을 향상시키기 위한 방법에 대해 소개한다. 특히 메시지의 흐름(call flow)이나 인코딩 방식과 같은 각 MGC에 종속적인 부분에 있어서 호환성을 지원하기 위해 고려되어야 할 사항과 이를 해결하기 위한 방법에 대해 소개하고 성능 평가를 하였다.

• Toxicological Research
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• 제33권3호
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• pp.191-203
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• 2017

Human eyes and skin are frequently exposed to chemicals accidentally or on purpose due to their external location. Therefore, chemicals are required to undergo the evaluation of the ocular and dermal irritancy for their safe handling and use before release into the market. Draize rabbit eye and skin irritation test developed in 1944, has been a gold standard test which was enlisted as OECD TG 404 and OECD TG 405 but it has been criticized with respect to animal welfare due to invasive and cruel procedure. To replace it, diverse alternatives have been developed: (i) For Draize eye irritation test, organotypic assay, in vitro cytotoxicity-based method, in chemico tests, in silico prediction model, and 3D reconstructed human cornealike epithelium (RhCE); (ii) For Draize skin irritation test, in vitro cytotoxicity-based cell model, and 3D reconstructed human epidermis models (RhE). Of these, RhCE and RhE models are getting spotlight as a promising alternative with a wide applicability domain covering cosmetics and personal care products. In this review, we overviewed the current alternatives to Draize test with a focus on 3D human epithelium models to provide an insight into advancing and widening their utility.

• 한국CDE학회논문집
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• 제13권5호
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• pp.372-381
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• 2008

We developed a design automation system to reduce the lead time and help engineers in designing a solid fuel, or a grain, for rocket missiles. First, we analyzed design activities and shapes of a grain, which resulted in the standard of design process and shape. We decided development process which consisted of two typical activities such as constructing master library and implementing design system. We constructed some master models for typical external shapes and core shapes of grains which were used in modeling the shape of a designing grain. Also we implemented a design automation program to use the master models according to the pre-defined design process. It can calculate some design parameters such as mass, mass center, volume and combustion area that are used in analyzing a proposed grain. Finally, we could reduce the design time dramatically and increase design quality by automating many routine and difficult works.

• Restorative Dentistry and Endodontics
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• 제16권1호
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• pp.151-157
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• 1991

The roles of temporary sealing materials used in endodontics are impotant Especially, its marginal sealing properties affect endodontic success and failure in endodontic treatment The purpose of this in vitro study was to compare and evaluate the marginal sealing properties of various temporary restorative materials used in endodontic access cavity by using electrochemical method. Standard endodontic access cavities were prepared in extracted human molar teeth and filled with Caviton, IRM, zinc oxide - eugenol cement. Each specimen was immersed in 1 % solution of KCl, and applied a potential of 9 V external power supply. Marginal microleakage and water sorption were measured for marginal sealing effect evaluation in comparison with each group. A comparative study of the obtained results have led to the following conclusions. 1. The Caviton group showed lower marginal microleakage value than the zinc oxide - eugenol cement and IRM group the 6 th day after. The IRM group showed lwoer marginal microleakage value than the zinc oxide - eugenol cement group from the 6 th day to the 12 th day. But there was no significant difference between zinc oxide - eugenol cement and IRM group after the 13 th day. 2. As time went by, marginal microleakage value was increased in Caviton, IRM and zine oxide - eugenol cement.