• International Journal of Computer Science & Network Security
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• 제22권5호
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• pp.55-60
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• 2022

Acceleration of the pace of life, increasing the amount of information, the emergence of "clip way of thinking" as a phenomenon has led to the problem of choosing forms of presentation of educational materials to students. One of the ways to solve this problem is to use the means of visualization of information flow, forasmuch as the thinking of modern youth is more effective in perceiving visual images than verbal means. The purpose of the research is to prove the effectiveness of the use of visualization in the process of teaching Ukrainian as a foreign language to students with clip way of thinking. The following methods have been used, namely: analysis, synthesis, comparison, systematization and generalization of scientific literature; testing and surveys; pedagogical experiment; quantitative and qualitative analysis of data, interpretation and generalization of the research results. The essence of visualization means has been revealed; the expediency of their use in the methodology of teaching foreign students the Ukrainian language has been substantiated. It has been proven that the role of Ukrainian teachers lies in taking into account all new trends in teaching, integrating computer perception of information by foreign students into teaching technology and using cognitive visualization in order to intensify the learning process.

• 한국가시화정보학회지
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• 제14권3호
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• pp.22-27
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• 2016

A sweeping jet actuator (SJA) is an instrument generating pulsing jets with no moving elements. Because of its simple design and high durability to shock and vibration, SJA has recently drawn increasing attention for the application to flow control such as aerodynamic control of a wing and thrust vectoring of a jet engine. However, experimental and numerical studies on SJA have been limited to internal flow structure of SJA. In this study, we investigated the flow structure and its variation in the outlet of SJA. We carried out the experiment to understand the flow structures using PIV (Particle Image Velocimetry). The flow structure varies with a degree of the outlet and volume flow rate. There is leaking process during half jetting cycle. The process of the main jet can occur because the jet moving time increased from one side to the other side.

• 한국마린엔지니어링학회:학술대회논문집
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• 한국마린엔지니어링학회 2011년도 후기공동학술대회 논문집
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• pp.61-61
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• 2011

Cavitation phenomena during the injection process of the conventional fuel injection pump for a medium-speed diesel engine can cause surface damage with material removal or round-off on the plunger and barrel port and may shorten their expected life time. An experiment of flow visualization was carried out to investigate the main cause of these cavitation damages and find the prevention method. Experimental results of flow visualization show that these damages are mainly affected by fountain-like cavitation and jet-type cavitation generated before and after the end of fuel delivery process and therefore the prevention method was designed to control these cavitation flows. From the visualization and endurance test, it was proved that this method can effectively prevent cavitation damages by controlling cavitation flows.

• 한국가시화정보학회지
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• 제19권2호
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• pp.48-55
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• 2021

In order to design a propeller with high efficiency and excellent cavitation performance, theoretical and experimental studies on the cavitation and noise characteristics according to the blade section shape are essential. In general, sheet cavitation, bubble cavitation, and cloud cavitation are the main causes of hull vibration and propeller surface erosion. However vortex cavitation, which has the greatest influence on the noise level because the fastest CIS in ship propeller, has been researched for a long time and studies have been conducted recently to control it. In this experiment, the development process of cavitation was measured by using three dimensional wings with two different wing section and wing tip shapes, and the noise level at that time was evaluated. In addition, we evaluated the relationship between cavitation inception and hydrodynamic force using three component load cell and we measured the velocity field of wing wake using LDV.

• 한국IT서비스학회지
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• 제21권2호
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• pp.85-95
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• 2022

This study analyzed the translation error factors of machine translation services such as Naver Papago and Google Translate through Self-Attention path visualization. Self-Attention is a key method of the Transformer and BERT NLP models and recently widely used in machine translation. We propose a method to explain translation error factors of machine translation algorithms by comparison the Self-Attention paths between ST(source text) and ST'(transformed ST) of which meaning is not changed, but the translation output is more accurate. Through this method, it is possible to gain explainability to analyze a machine translation algorithm's inside process, which is invisible like a black box. In our experiment, it was possible to explore the factors that caused translation errors by analyzing the difference in key word's attention path. The study used the XLM-RoBERTa multilingual NLP model provided by exBERT for Self-Attention visualization, and it was applied to two examples of Korean-Chinese and Korean-English translations.

• 인터넷정보학회논문지
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• 제25권1호
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• pp.177-188
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• 2024

기술이 발전함에 따라 인터넷 사용량은 더욱 증가하고 있으며, 이를 통해 네트워크 트래픽 및 통신량이 기하학적으로 증가하고 있다. 인터넷의 핵심 요소 중 하나인 네트워크 경로 선택 프로세스는 이에 따라 더욱 복잡하고 고도화되고 있으며, 이를 효과적으로 관리하고 분석하는 것이 중요하다. 또한 이를 직관적으로 이해할 수 있는 표현 및 가시화 방안이 필요하다. 이를 위해 본 연구에서는 네트워크 경로 선택 방법인 BGP를 사용하여 네트워크 데이터를 분석하고, 상황인식을 위한 사이버 공통작전상황도에 이를 적용하는 프레임워크를 설계한다. 그 후 정보들을 가시화하기 위해 필요한 작전상황도 가시화 요소들을 분석하고 간단한 가시화를 구현하는 실험을 진행한다. 실험에서 수집되고 전처리된 데이터를 기반으로 구현된 가시화 화면들을 통해 지휘관 또는 보안 담당자들이 네트워크 상황을 효과적으로 파악하고 명령 및 제어를 할 수 있도록 도움을 준다.

• 한국가시화정보학회:학술대회논문집
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• 한국가시화정보학회 2005년도 추계학술대회 논문집
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• pp.64-68
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• 2005

In this study, the smoke flows of the inner subway station were visualized through a numerical analysis and visualization experiment in the subway fire. A transparent acrylic model was designed and installed as 1:25th scale-down as the actual subway station by using geometrical similarity The properties of subway fire were reconstructed according to Densimetric Froude Similarity. The 47 to 53 ratio of the mixed air and Helium was inputted in the inner acrylic model to describe 1MW fire intensity with reference to the experiment paper. For the same time, the fire smoke from a smoke generator was inputted in the inner acrylic model with the mixture. At this time, the buoyancy effect of Helium gas went up the smoke to the acrylic model. When the sheet beam of Ar-lon laser was given out to the top and stair of subway model, the digital camcorder took the images of the scattered cluster of smoke particles when applying the smoke management system and PSD.

• 대한설비공학회지:설비저널
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• 제17권4호
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• pp.382-394
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• 1988

Dynamic characteristics of thermally-forced stratification process in a square enclosure with a linear temperature profile at the side walls have been investigated through flow visualization experiment and numerical analysis. The experiment was performed on air with the Rayleigh numbers of order $10^5$. A particle tracer method is used for the flow visualization and to obtain a sudden linear temperature profile at the side walls copper blocks which already have a linear temperature profile are come into contact with the thin copper plates of the test section. Immediately a meridional circulation is developed and heat transfer takes place from the wall to the interior region by circulation of fluid and finally a thermal stratification is achieved. In the numerical study, QUICK scheme for convective terms, SIMPLE algorithm for pressure correction, and the implicit method for the time marching are adopted for the integration of conservation equations. Comparison of flow visualization and numerical results shows that the developing flow patterns are very similar in dynamic nature even though there is a time lag due to the inevitable time delay in setting up a linear temperature profile. For high Rayleigh numbers, the oscillatory motion is likely to take place and stratified region is extended. However, initial temperature adjustment process is much slower than that for low Rayleigh numbers.

• 한국가시화정보학회지
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• 제20권3호
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• pp.102-108
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• 2022

In the fan module of the intercooling refrigerator, a drain hole structure was designed for stable drainage of defrost water. However, the airflow passing through the drain hole can disturb flow features around the evaporator. Since this backflow leads to an increase in flow loss, the accurate experimental and numerical analyses are important to understand the flow characteristics around the fan module. Considering the complex geometry around the fan module, three different turbulence models (Standard k-ε model, SST k-ω model, Reynolds stress model) were used in computational fluid dynamics (CFD) analysis. According to the quantitative and qualitative comparison results, the Standard k-ε model was most suitable for the research object. High-accuracy results well match with the experiment result and overcome the limitation of the experiment setup. The method used in this study can be applied to a similar research object with an orifice outflow driven by a rotating blade.

• 한국가시화정보학회지
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• 제9권4호
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• pp.47-53
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• 2011

A water driven ejector loop was designed and constructed for air absorption. The used ejector was horizontally installed in the loop and annular water jet at the throat entrained air through the circular pipe placed at the center of the ejector. Wide range of water flow rate was provided using two kinds of pumps in the loop. The tested range of water flow rate was 100${\ell}$ /min to 1,000 ${\ell}$/min. Two-phase flow inside the ejector loop was simulated by CFD analysis. Homogeneous particle model was used for void fraction prediction. Water and air flow rates and pressure drop through the ejector were automatically recorded by using the LabView based data acquisition system. Flow characteristics and air bubble velocity field downstream of the ejector were investigated by two-phase flow visualization and PIV measurement based on bubble shadow images. Overall performance of the two-phase ejector predicted by the CFD simulation agrees well with that of the experiment.