• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회B
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• pp.3142-3147
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• 2008

A simple transient simulation of ground source heat pump system was carried out to investigate the effects of ground thermal conductivity on its performance. The TRNSYS code with a simple water to water heat pump model was used to compare the COP variation of the system. A new ground heat exchanger called by semi-closed loop was proposed and constructed in the real site. The effective thermal conductivity was measured using the test equipment developed by according to the line source model. The simulation results showed that highly efficient thermal conductivity of the grout material could increase the performance of the heat pump system very well. And the new ground heat exchanger showed the increased effective thermal conductivity as the penetration water flow rate(PWFR) was increased. Therefore, the performance improvement of the heat pump system using the proposed ground heat exchanger can be expected.

• 반도체디스플레이기술학회지
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• 제19권2호
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• pp.51-54
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• 2020

To develop gas-distinguishing sensor system, it is highly required to integrate multiple sensors for effective detection of a single targeted gas or mixture of gases. In addition, it is important to collect the reliable data from individual sensors into one integrated measuring device. Collecting the data of toxic gases on the spot should be done without inhalation. We suggest simple wirelessly running system for data collection that guarantees both reliability of data sources and safety. Here, we made a multi-gas measuring instrument(device) combined with Bluetooth module which provides a safe and precise big data accumulation system.

• 한국정보처리학회논문지
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• 제6권10호
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• pp.2642-2648
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• 1999

This paper describes a DAVIC based VoD service system that allows access via the Web, taking advantage of the wide availability of Web browsers. A simple access mechanism of a DAVIC based VoD system, using a Web browser is adopted on the proposed system. The client and VoD server are compliant with DAVIC, a user can access the VoD server simply by selecting the Web server's address via a Web browser. A menu enables the user to select VCR-like buttons, to establish an S2 control flow and to send the commands contained in the buttons to the VoD server. A simple implementation shows the feasibility of the proposed approach.

• Journal of Electrical Engineering and Technology
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• 제9권5호
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• pp.1582-1591
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• 2014

This paper presents a hybrid sensorless control for an interior permanent magnet synchronous motor (IPMSM) for zero-, low-, and high-speed regions. Many sensorless control methods such as an observer-based estimator have been introduced. However, most of the observer-based estimators have a disadvantage at start-up and in the low-speed region. To solve this problem, a simple strategy of using a hybrid system is proposed by integrating a high-frequency (HF) signal injection method and a full-order flux observer. In addition, an HF signal injection method with only a low pass filter (LPF) is proposed to simplify the hybrid system. The hybrid system achieves high-performance drive throughout the entire speed range. The effectiveness of the proposed hybrid technique is verified by experiments using an 11-kW IPMSM drive system.

• 한국정밀공학회지
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• 제16권9호
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• pp.166-171
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• 1999

An overhead crane system consists of trolley, girder, rope, object, trolley motor, girder motor, and hoist motor. An analytic model which derived from the modelling of the overhead crane system is nonlinear model which includes the swing and the twist angle of the object. this model consists of the equation of motion for motors and object. If the swing angle and the acceleration of Z for the object are small, this model becomes a simple nonlinear model which doesn't include the swing and the twist angle of the object. From the results of computer simulation, the characteristics of an actual overhead crane system could be predicted by the simple nonlinear model.

• Restorative Dentistry and Endodontics
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• 제48권1호
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• pp.7.1-7.10
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• 2023

Objectives: This study aimed to evaluate the surrounding and underlying shades' effect on the color adjustment potential (CAP) of a single-shade composite used in a thin layer. Materials and Methods: Cylinder specimens (1.0 mm thick) were built with the Vittra APS Unique composite, surrounded (dual specimens) or not (simple specimens) by a control composite (shade A1, A2, or A3). Simple specimens were also built only with the control composites. Each specimen's color was measured against white and black backgrounds or the simple control specimens with a spectrophotometer (CIELAB system). The whiteness index for dentistry (WI_D) and translucency parameters (TP₀₀) were calculated for simple specimens. Differences (ΔE₀₀) in color between the simple/dual specimens and the controls were calculated. The CAP was calculated based on the ratios between data from simple and dual specimens. Results: The Vittra APS Unique composite showed higher WID and TP₀₀ values than the controls. The highest values of ΔE₀₀ were observed among simple specimens. The color measurements of Vittra APS Unique (simple or dual) against the control specimens presented the lowest color differences. Only surrounding the single-shade composite with a shaded composite barely impacted the ΔE₀₀. The highest CAP values were obtained using a shaded composite under simple or dual specimens. Conclusions: The CAP of Vittra APS Unique was strongly affected by the underlying shade, while surrounding this composite with a shaded one barely affected its color adjustment.

• 한국멀티미디어학회논문지
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• 제12권9호
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• pp.1342-1350
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• 2009

현재까지 디지털 디스플레이 시스템은 단순영상의 시연용, 감상용, 전시용 시스템이 대부분이며 음악과 움직이는 풍경으로 인해 색다른 영상작품으로 재해석되어 보여 질 수 있으며 사용자의 감수성을 자극한다는 장점을 가지고 있지만 개발된 시스템의 활용범위가 작고, 쉽게 흥미를 잃을 수 있는 시기성을 가진다는 단점이 있어 지속적인 사용자의 인터랙션을 유도할 수 있는 시스템이 필요하다. 따라서 본 논문에서 제안한 RSS기반 디지털 병풍 시스템은 사용자의 단순 감상용으로 활용하던 기존의 8폭 병풍의 한계를 극복하여 사용자가 직접 참여하고 체험할 수 있는 환경을 제공하고 필요한 정보를 효과적으로 획득 할 수 있는 인터랙티브 미디어 시스템으로써 의 활용을 목적으로 구현되었다. 본 시스템은 블로그나 사이트를 직접 방문하지 않아도 새로 등록된 글을 수집해 읽을 수 있는 RSS의 주된 기능을 적용하여 실시간으로 필요한 정보를 사용자의 의도에 맞게 전달 할 수 있어 평상시에는 관상용으로 콘텐츠를 감상할 수 있고, 필요에 따라 광고나 전시용으로 활용이 가능하며, 공공장소의 정보전달시스템으로도 사용가능한 장점을 가지고 있다.

• 대한방사선기술학회지:방사선기술과학
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• 제28권1호
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• pp.19-24
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• 2005

방사선사를 위한 교육 및 영상 정보에 대한 정확한 판단에 유용한 주석-기반 방사선 의료영상 검색 시스템을 설계 및 구현하고, 방사선 의료영상에 대한 단순 속성정보, 부가적인 정보인 텍스트 설명정보로부터 추출한 중요 키워드에 대한 효율적인 검색을 위해 $B^+$-트리와 역화일 기법을 이용한 색인기법을 제안하고자 한다. 윈도우즈 XP에서 Delphi를 이용하여 구현하였으며, 방사선사는 방사선 의료영상에 대한 속성 정보, 부가적인 설명정보, 이미지 정보를 저장하도록 하고, 구축된 영상 데이터베이스로부터 속성정보와 텍스트 키워드 정보를 이용하여 검색 가능하도록 하였다. 임상방사선사가 단순속성정보 및 텍스트 설명정보를 찾아냄으로써 임상현장에서의 체계적인 교육뿐 만 아니라 지식을 구조화함으로써 교육시간의 단축과 방사선 의료영상에 대해 정확한 판단을 내릴 수 있다. 구현되어진 방사선 의료영상검색 시스템은 차후에 일반촬영, 특수조영영상을 포함한 통합화상시스템으로의 확장이 요구되며, 아울러 웹을 통한 서비스를 구축함으로써 의사결정시스템으로 발전 할 수 있는 기반기술로 기대된다.

• Structural Engineering and Mechanics
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• 제52권2호
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• pp.275-290
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• 2014

In this paper, Simple Adaptive Control (SAC) method is used to mitigate the detrimental effects of earthquakes on MR-damper equipped structures. Acceleration Feedback (AF) is utilized since measuring the acceleration response of structures is known to be reliable and inexpensive. The SAC is simple, fast and as an adaptive control scheme, is immune against the effects of plant and environmental uncertainties. In the present study, in order to translate the desired control force into an applicable MR damper command voltage, a neural network inverse model is trained, validated and used through the simulations. The effectiveness of the proposed AF-based SAC control system is compared with optimal H2/LQG controllers through numerical investigation of a three-story model building. The results indicate that the SAC controller is substantially effective and reliable in both undamaged and damaged structural states, specifically in reducing acceleration responses of seismically excited buildings.

• Journal of the Korean Statistical Society
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• 제28권3호
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• pp.337-346
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• 1999

Simple correspondence analysis is a technique for giving a joint display of points representing both the rows and columns of an n$\times$p two-way contigency table. In simple correspondence analysis, the singular value decomposition is the main algebraic tool. But, Choi and Huh(1996) pointed out the singular value decomposition is not robust. Instead, they developed a robust singular value decomposition and provided applications in principal component analysis and biplots. In this article, by using the analogous procedures of Choi and Huh(1996), we derive a robust version of simple correspondence analysis.