• 한국가시화정보학회지
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• 제21권3호
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• pp.75-84
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• 2023

In this study, we conducted analysis of bubble dynamics and flow of liquid phase change material(PCM) using shadowgraphy and particle image velocimetry(PIV). Characteristics of internal flow varied depending on locations of injection when solid PCM was liquefied from heated vertical wall. When bubbles rose immediately, they exhibited elliptical shape and zigzag trajectory. In contrast, when bubbles rose after merging at the bottom of solid PCM, with equivalent diameter for the inter-wall distance of 0.64 or greater, they showed a jellyfish shape and strong rocking behavior. It was observed by the PIV that the small ellipse bubbles made most strong flow inside the liquid PCM. Furthermore, the flow velocity was highest in the case of front injection, as the directions of temperature gradients and bubble-driven flow were aligned. The results underscore the significant influence of injection location on various characteristics, including bubble size, shape, rising path of bubbles, and internal flow.

• 문화기술의 융합
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• 제7권3호
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• pp.303-310
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• 2021

거시적 데이터 변화를 단순한 형태로 유추 비교 및 분석하는 시각 정보 콘셉트 개발방법이 필요하다. 시각 정보 콘셉트의 개발에는 시각화 형태 선택, 수사학적 효과 선택 그리고 디지털 표현요소 선택 작업이 필요한데, 이 중에서, 사용자에게 시각 정보를 효과적으로 전달하기 위한 수사학적 효과 선택 방법의 예를 제시한다. 본 연구에서는 기간별 및 업종별 주가 분석을 위해서, 원관념과 비유되는 보조관념을 통하여 거시적 관점에서 데이터 비교 분석이 가능한 메타포 수사학을 선택했다. 갓털이 퍼져나가는 민들레를 메타포로 사용한 2차원 3단 형태 변화와 시간에 변화 따라서 형태와 색상이 변하는 코랄 작약 꽃송이를 메타포로 사용한 3차원의 3단 형태 변화 정보표현 방식을 제시한다. 이러한 수사학적 메타포를 사용하면, 거시적인 거래 변화와 업종별 주가 비교 분석이 가능하다.

• 한국가시화정보학회지
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• 제11권2호
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• pp.46-54
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• 2013

Study of the wave structure and shear layer in the vicinity of a wall mounted cavity is done by time averaged colour schlieren and time resolved instantaneous shadowgraph technique in an M=1.7 flowfield. Effect of change of cavity width on flow structure is investigated by using constant length to depth (L/D) ratio cavity models with varying length to width (L/W) ratio of 0.83 to 4. The time averaged shock wave structure was observed to change with change in cavity width. Dependence of the shock angle at the leading edge on the shear layer width is also evident from the images obtained. Unsteadiness in the flow field in terms of shear layer dynamics and quasi steady nature of shock waves was evident from the images obtained during instantaneous shadowgraph experiments. Apart from the leading and trailing edge shocks, several other waves and flow features were observed. These flow features and the associated physical phenomena are discussed in details and presented in the paper.

• ETRI Journal
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• 제30권6호
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• pp.757-764
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• 2008

In this paper, we present a design evaluation system with visualization and interaction of mobile devices using virtual-reality-based prototypes which can be used to easily change design parameters and simulate embedded software. To evaluate and predict affective-engineering-based design preferences for mobile devices under a virtual environment, we have developed a high quality visualization platform which creates images that look similar to real mobile devices in addition to real-time simulation of realistic motions and functions of mobile devices. To support a quantitative usability test scenario for external design shape, we also have built a system which consists of a mixed-reality-based testing platform for measuring hand load.

• 한국가시화정보학회지
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• 제8권2호
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• pp.31-39
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• 2010

Hysteresis is an effect by which the order of previous events influences the order of subsequent events. Hysteresis phenomenon of supersonic internal flows with shock waves has not yet been clarified satisfactorily. In the present study, experiments are carried out on internal flow in a supersonic nozzle to clarify the hysteresis phenomena for the shock waves. Flow visualization is carried out separately on the straight and divergent channels downstream of the nozzle throat section. Results obtained were compared with numerically simulated data. The results confirmed hysteresis phenomenon for shock wave in the Laval nozzle at a certain specific condition. The relationship between hysteresis phenomenon and the range of the rate of change of pressure ratio with time was shown experimentally. The existence of hysteretic behavior in the formation, both the location and strength, of shock wave in the straight part of the supersonic nozzle with a range of pressure ratio has also been confirmed numerically.

• Journal of Information Science Theory and Practice
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• 제7권2호
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• pp.32-39
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• 2019

A convolutional neural network (CNN) has been widely used in facial expression recognition (FER) because it can automatically learn discriminative appearance features from an expression image. To make full use of its discriminating capability, this paper suggests a simple but effective method for CNN based FER. Specifically, instead of an original expression image that contains facial appearance only, the expression image with facial geometry visualization is used as input to CNN. In this way, geometric and appearance features could be simultaneously learned, making CNN more discriminative for FER. A simple CNN extension is also presented in this paper, aiming to utilize geometric expression change derived from an expression image sequence. Experimental results on two public datasets (CK+ and MMI) show that CNN using facial geometry visualization clearly outperforms the conventional CNN using facial appearance only.

• 한국정보통신학회논문지
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• 제26권1호
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• pp.146-152
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• 2022

라즈베리 파이나 아두이노를 이용하여 온도, 습도, 기울기, 압력 센서 등에서 수집한 정보는 자동 항온, 항습 시스템 등에 활용되고 있다. 또 농축산업에 활용하여 원격에서 스마트폰만으로 시스템을 제어함으로써 농축산업 종사자들이 편리하게 활용하기도 한다. 일반적으로 온도, 습도는 꺾은선 그래프 등으로 표현하여 변화를 실시간으로 감시하는 역할을 수행하기도 한다. 온도를 시각적으로 표현하는 기술은 최근 코로나19의 발열 검사를 위해 적외선 기기를 이용해 직관적으로 활용되기도 한다. 본 논문에서는 라즈베리 파이와 DHT11 센서에서 수집된 정보를 직관적인 시각화를 통해 공간상의 온도변화를 예측하고 즉각적인 대응이 가능하도록 제안한다. 이를 위해 온도, 습도를 효과적으로 시각화하기 위해 알고리즘을 만들었고, 일부 센서에 결함이 발생하는 경우에도 데이터 표현이 가능하다.

• 대한지리학회:학술대회논문집
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• 대한지리학회 2004년도 추계학술대회
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• pp.60-60
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• 2004

• 인터넷정보학회논문지
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• 제22권3호
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• pp.59-66
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• 2021

이 연구에서는 소프트웨어 개발 과정에서 소프트웨어 시스템의 품질을 높이기 위해 요구사항에 대한 추적성 관리 및 변경 관리를 체계적으로 수행하는 요구사항 모니터링 방법을 제안한다. 이를 위해 산출물 간 연관 관계를 정의하기 위한 추적 매트릭스와 개별산출물들에 대한 변경 관리를 체계적으로 수행하기 위한 산출물 변경 이력 관리 모델을 제시한다. 또한 특정 산출물이 변경될 때 연관된 산출물에 변경이 파급되는 상황을 쉽게 파악할 수 있도록 하는 시각적 대시보드도 제안한다.

• 한국가시화정보학회지
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• 제21권2호
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• pp.34-45
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• 2023

When lithium-ion batteries operate out of the proper temperature range, their performance can be significantly degraded and safety issues such as thermal runaway can occur. Therefore, battery thermal management systems are widely researched to maintain the temperature of Li-ion battery cells within the proper temperature range during the charging and discharging process. This study investigates the cooling performance and isothermal maintenance of cooling materials by measuring the surface temperature of a battery cell with or without cooling materials, such as silicone oil, thermal adhesive, and phase change materials during discharge process of battery by the experimental and numerical analysis. As a result of the experiment, the battery pack filled with phase change material showed a temperature reduction of 47.4 ℃ compared to the case of natural convection. It proves the advanced utility of the cooling unit using phase change material that is suitable for use in battery thermal management systems.