• 한국CDE학회논문집
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• 제21권3호
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• pp.224-233
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• 2016

We propose a new method to visualize 3D models for FDM (Fused Deposition. Modeling) printing that appearance of the printed results can be predicted more realistically as that the efficiency of the modeling-printing process can be improved. The layered nature of horizontal slicing and the vibratory nozzle movements of customer-level FDM 3D printers leaving the characteristic patterns of noisy stripes on the surfaces of printed objects make difficulties in prediction of printed result in company with the thermal contraction of filament material. First, our method analyses the G-codes generated by common slicers to obtain proper outlines and take advantages of a modified version of Perlin noise based texturing method for rendering efficiency and enough number of control parameters on the visual details. The results show improved rendering details of pre-visualization of FDM printing.

• 한국가시화정보학회지
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• 제19권3호
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• pp.115-122
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• 2021

Oral cancer surgery typically consists of resection of lesion, neck dissection and reconstruction, and it has an impact on the position of hyoid bone. Therefore, morphological change of airway can occur since the geometric parameter of airway is correlated with the hyoid bone. Airflow is affected by geometry of the airway. In this study, flow characteristics were compared between pre- and post-surgery models by both particle image velocimetry (PIV) and numerical simulation. 3D model of upper airway was reconstructed based on CT data. Velocity is accelerated by the reduced channel area, and vortex and recirculation region are observed in pre- and post-surgery models. For the post-surgery model, high pressure distribution is developed by significantly decreased hydraulic diameter, and the longitudinal flow stream is also interrupted.

• 동력기계공학회지
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• 제21권3호
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• pp.12-18
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• 2017

Diesel and gasoline engines will be used as main power system of automobiles. Recently, engine downsizing is widely applied to both gasoline and diesel engines in order to improve fuel economy and exhaust emissions. Engine downsizing means small engine combustion chamber with higher combustion pressure. Therefore, spray and combustion process should be investigated under these high pressure and temperature conditions. In this study, constant volume combustion chamber which enables easy optical access from six directions was developed. Combustion chamber was designed to resist maximum pressure of 15 MPa and maximum temperature of 2,000 K. Combustible pre-mixed mixture was introduced into combustion chamber and ignited by spark plugs. High pressure and temperature were implemented by combustion of pre-mixed mixture. Three initial conditions of different pressure and density were tested. High repeatability of combustion process was implemented which was proven by low standard deviation of combustion pressure.

• 한국방송∙미디어공학회:학술대회논문집
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• 한국방송공학회 1999년도 디지털 방송기술 워크샵
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• pp.117-138
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• 1999

.8-VSB Modulator for Digital Television . ERRI'S ATSC VSB EXCITER . Pre-Corrector . Field Test . Lab Test

• Journal of the Korean Data and Information Science Society
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• 제28권6호
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• pp.1301-1311
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• 2017

제조 빅데이터 시스템은 제조 전 공정에서 관련된 4M 데이터의 수집, 저장, 관리, 예측적 분석을 통해 선제적 제조 활동 개선이 가능한 의사결정을 지원하고 있다. 이러한 시스템에서 데이터의 효율적인 관리와 운영을 위해 데이터를 효과적으로 시각화하는 것이 무엇보다도 중요하다. 본 논문에서는 제조 빅데이터 시스템에서 데이터 수집, 분석 및 예측 결과를 효과적으로 보여 주기 위해 사용가능한 시각화 기법을 제시한다. 본 논문에서 제시된 시각화 기법을 통해 제조 현장에서 발생하는 문제를 보다 손쉽게 파악할 수 있었을 뿐만 아니라 이들 문제를 효과적으로 대응할 수 있어 매우 유용하게 사용될 수 있음을 확인하였다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제15권2호
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• pp.749-766
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• 2021

Cyber powers around the world are conducting cyber information-gathering activities in cyberspace, a global domain within the Internet-based information environment. Accordingly, it is imperative to obtain the latest information through the cyber intelligence preparation of the battlefield (IPB) process to prepare for future cyber operations. Research utilizing the cyber battlefield visualization method for effective cyber IPB and situation awareness aims to minimize uncertainty in the cyber battlefield and enable command control and determination by commanders. This paper designed architecture by classifying cyberspace into a physical, logical network layer and cyber persona layer to visualize the cyber battlefield using BGP archive data, which is comprised of BGP connection information data of routers around the world. To implement the architecture, BGP archive data was analyzed and pre-processed, and cyberspace was implemented in the form of a Di-Graph. Information products that can be obtained through visualization were classified for each layer of the cyberspace, and a visualization method was proposed for performing cyber IPB. Through this, we analyzed actual North Korea's BGP and OSINT data to implement North Korea's cyber battlefield centered on the Internet network in the form of a prototype. In the future, we will implement a prototype architecture based on Elastic Stack.

• 한국가시화정보학회지
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• 제2권2호
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• pp.45-51
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• 2004

Initial flame development and propagation were visualized under different fuel injection timings to relate the initial flame development to the engine stability in a port injection SI engine. Experiments were performed in an optical single cylinder engine modified from a production engine and images were captured through the quartz window mounted in the piston by an intensified CCD camera. Stratification state was controlled by varying injection timing. Under each injection condition, the flame images were captured at the pre-set crank angles. These were averaged and processed to characterize the flame. The flame stability was estimated by the weighted average of flame area, luminosity, and standard deviation of flame area. Results show that stratification state according to injection timing did not affect on the direction of flame propagation. The flame development and the initial flame stability are strongly dependent on the stratified conditions and the initial flame stability governs the engine stability and lean misfire limit.

• 한국가시화정보학회지
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• 제22권2호
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• pp.90-95
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• 2024

This study examined changes in airway airflow characteristics before and after extensive surgery for tongue cancer, which includes neck dissection and reconstruction. Pre- and post-operative CBCT scans were used to model 3D upper airways. Computational fluid dynamics (CFD) simulations analyzed airflow and pressure variations. Results showed a significant reduction in airway volume post-surgery, especially in the posterior tongue and epiglottis areas, leading to increased airflow velocity and complex vortex formations. Pressure drop analysis revealed that post-surgery, higher negative pressure is required for inhalation, indicating increased breathing effort. This suggests that the surgical removal of cancerous tissues and lymph nodes, along with reconstruction, alters airway geometry significantly, potentially impacting respiratory function. The findings highlight the clinical importance of assessing airway changes in tongue cancer surgery to anticipate and mitigate postoperative respiratory complications.

• 한국초등과학교육학회지:초등과학교육
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• 제36권1호
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• pp.73-84
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• 2017

Cultivating creativity is one of the goals in science education. Previous studies report that students use visualization while they solve the creative science problem and it looks helpful to make them think more. For this study three $6^{th}$ grade students were selected in the consideration of pre-test through the qualitative think-aloud method. The results show that even though students have many ideas in planning stage in problem solving, they appeared to visualize familiar and empirical ideas at first. So if teachers want to watch another creative ideas, they tended to give enough time to visualize many ideas. Students drew lines, circles, "X"marks to select or remove information during their problem solving works. They said these marks seem to be useful to understand question. However, removal marks sometimes turn out to block another chance to re-think. Also students did not have a chance to reflect what they did. It means that they lose the chance to do convergent thinking. The implications of this study include the importance of students' visualization works to facilitate their creative ideas and support their problem solving strategies. In this study, we discuss the meaningful messages for teachers who construct science classroom for creativity.

• 대한조선학회논문집
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• 제42권5호
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• pp.487-492
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• 2005

The structural intensity analysis, which calculates vibration energy flow from vibratory velocity and internal force of a structure, can give information on sources' power, dominant transmission path and sink of vibration energy. In this study, we present a system for structural intensity analysis and visualization to apply for anti-vibration design of ship structures. The system calculates structural intensity from the results of forced vibration analysis and visualize the intensity using a general purpose finite element analysis program MSC/Nastran and its pre- and post-processor program. To demonstrate the analysis and visualization capability of the presented system, we show and discuss the results of structural intensity analysis for a cross-stiffened plate and a 70,500 OW crude oil tanker