• Journal of the Korean Society of Visualization
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• v.16 no.2
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• pp.53-58
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• 2018

This paper presents an electromagnetically driven microrobot for the enhancement of mixing performance in high viscous liquid media such as blood and bone marrow. First, an electromagnetic system was fabricated, and the magnetic flux density generated from the system was compared with the theoretical value. Second, the reciprocating motion of the microrobot was demonstrated in microchannel using electromagnetic system. As a proof of concept, the mixing performance by the electromagnetically driven microrobot in high viscous liquid was investigated using safranin solution. As a result, it was completely mixed within 140 s with the reciprocating motion of the microrobot while it took 1680 s for natural diffusion. In addition, the mixing efficiency was quantitatively evaluated through a mixing index obtained by an image analysis. The proposed method provides not only wireless actuation of a microrobot with a simple design but also high mixing performance in variety of high viscous liquid media.

• Journal of the Korean Society of Visualization
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• v.20 no.2
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• pp.13-20
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• 2022

An effective capacitive deionization process termed membrane capacitive deionization (MCDI) is newly designed and experimentally tested for seawater desalination. By preventing co-ions to be expelled, MCDI can improve the ion removal performance, but there is a trade-off between blocking co-ion transfer and increasing contact resistance. The conventional MCDI uses 2D-shaped films which increase contact resistance and reduce desalination performance in the trade-off. In this paper, with the 3-D shape of Nafion coated activated carbon cloth, the mentioned problems are expected to be solved making the desalination performance better. We visualized ion concentration and fluid flows with half-MCDI cell that can measure only efficiency of cathode. We found the optimal number of coatings which have the better efficiency than CMX, commercial cation exchange membrane in fixed current conditions of 100uA.

• Journal of Fisheries and Marine Sciences Education
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• v.26 no.6
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• pp.1373-1379
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• 2014

The purpose of this research is to evaluate the performance of the Ventilation hood and to make better oil collection for improvement. In order to complete the purpose, the research range has limited a kitchen cooking utensil used in preparing food in vessels. Assessment was carried out with reference(ASTM F1704-09) to the specification. Evaluation items of ventilation hood were flow visualization, oil collection rate and noise levels. When filter angle was 40 degrees, oil collection rate was increased by 9%.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.42 no.7
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• pp.561-566
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• 2014

Our Korean traditional cultural inheritance Bangpae Kite has the stable rectangular shield shape decorated with artistic paint or poem and a good flight performance due to the central wind hole. In this paper, to analyse the wind hole effect to kite performance we performed the wind tunnel testing of the various design factor of kite model and air flow visualization passing through the wind hole. As the result of aerodynamic analysis, we knew that the wind hole of kite displays similar function of slot system for the wing high lift device. This fact demonstrates that our ancestor understood the function of slot system and applied effectively to the development of kite flight performance.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.05a
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• pp.484-488
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• 2007

In this paper, the measurement system using the microphone array developed for analyzing cabin noise of the vehicle and its applications are discussed. The sensor is a three dimensional microphone array, the microphones and cameras are equipped on the rigid sphere. The cameras are used for acoustic visualization. As applications, the experiments in both reverberation chamber and anechoic chamber are discussed. These results show that this system is very useful to evaluate or improve the vehicle sound insulation performance.

• 한국HCI학회:학술대회논문집
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• 2009.02a
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• pp.572-578
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• 2009

This paper introduce a structure of haptic collaboration system over high resolution tiled-display, and proposes a object based efficient display method for high resolution display in integrated system. in addition, a modeling of visualization system is defined to evaluate performance of the proposed method. Both haptic system and tiled-display system have requirements of computational power. A haptic device is unstable if haptic rendering rate is less than 1kHz. A requirement of tiled-display systems is frame rate of display. It requires update of 30 frame fer sec. If we use these systems independently, we can satisfy each requirements. However, if we integrate two systems, performance of entire system significantly decreases because of lack of resources. In this paper, therefore, we propose a segmentation-based display method for ultra high resolution display in integrated system. The proposed method reduces redundancy of display data by reducing a display rate of static objects. Finally, a modeling of visualization system is defined to evaluate performance of the proposed method.

• Journal of Digital Contents Society
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• v.18 no.8
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• pp.1621-1626
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• 2017

This study conducts data visualization of common climax patterns of Korean blockbuster films to analyze shots and evaluate scene (subplot unit) arrangement. For this purpose, a model of editing patterns is used to analyze how many climax patterns a film contains. Moreover, a system, which automatically collects shot images and classifies shot sizes of collected data, is designed to demonstrate that a single scene is composed based on a climax pattern. As a scene is a subplot and thus its arrangement cannot fully be analyzed only by climax patterns, dialogues of starring actors are also used to identify scenes, and the result is compared with data visualization results. It detects dialogues between particular actors and visualizes dialogue formation in a network form. Such network visualization enables the arrangement of main subplots to be analyzed, and the box office performance of a film can be explained by the density of subplots. The study of two types comparison analysis is expected to contribute to planning, plotting, and producing films.

• 한국HCI학회:학술대회논문집
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• 2009.02a
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• pp.84-89
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• 2009

Personal mobile devices such as mobile phone, PMP and MP3 player have advanced incredibly. Such advance in mobile technology ignites the research related to the life-log to understand the daily life of an user. Since life-log collected by mobile sensors can aid memory of the user, many researches have been conducted. This paper suggests a methodology for user-context recognition and visualization based on the outdoor location by GPS as well as indoor location by wireless-lan. When the GPS sensor does not work well in an indoor location, wireless-lan plays a major role in recognizing the location of an user so that the recognition of user-context become more accurate. In this paper, we have also developed the method for visualization of the life-log based on map and blog interfaces. In the experiments, subjects have collected real data with mobile devices and we have evaluated the performance of the proposed visualization and context recognition method based on the data.

• International Journal of Computer Science & Network Security
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• v.21 no.8
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• pp.35-42
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• 2021

In the current context of digitalization of education, the use of modern methods and techniques of data analysis and processing in order to improve students' school results has a very important role. In our paper, we aimed to perform a comparative study of the classification performances of AdaBoost, SVM, Naive Bayes, Neural Network and kNN algorithms to classify the results obtained at the Baccalaureate by students from a college in Suceava, during 2012-2019. To evaluate the results we used the metrics: AUC, CA, F₁, Precision and Recall. The AdaBoost algorithm achieves incredible performance for classifying the results into two categories: promoted / rejected. Next in terms of performance is Naive Bayes with a score of 0.999 for the AUC metric. The Neural Network and kNN algorithms obtain scores of 0.998 and 0.996 for AUC, respectively. SVM shows poorer performance with the score 0.987 for AUC. With the help of the HeatMap and DataTable visualization tools we identified possible correlations between classification results and some characteristics of data.

• Journal of the Korean Society of Visualization
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• v.21 no.2
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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.