• 한국문헌정보학회지
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• 제39권2호
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• pp.287-304
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• 2005

이 연구의 목적은 자동적으로 추출된 정보를 시각화 브라우저를 통해 표현하고 접근하는 방법에 대해 이용성평가를 수행하는 것이다. 특정 주제 분야에 국한되지 않는 정보추출시스템을 사용하여 신문기사에서 의미정보를 자동 추출하였고, 그 결과로 시각적으로 브라우저 할 수 있는 지식베이스를 구축하였다. 이 연구에 이용된 정보추출시스템은 신문기사의 텍스트정보로부터 다양한 자연언어처리 기술을 적용하여 개념-관계-개념의 형태로 표현되는 정보를 자동적으로 추출하였다. 지식베이스에 저장된 정보를 시각적으로 표현하는 시각화 브라우저를 구현하였는데, 이때 인터페이스 부분은 쌍곡면형 정보시각화 시스템의 하나인 PersonalBrain을 이용하여 개발하였다. PersonalBrain을 이용하면 표현하고자 하는 정보를 논리관계의 네트워크 형태로 연결할 수 있다. 지식베이스 정보의 시각화 접근방법에 대하여 15명의 이용자를 대상으로 질적 평가를 수행하였다. IS명의 연구대상자로 하여금 시각화 브라우저를 이용하도록 하고 관찰과 인터뷰를 통하여 이용성평가 데이터를 수집하였다. 내용분석결과, 이용자들은 정보추출결과의 시각화 브라우저 이용가능성에 대해 긍정적인 반응을 보인 동시에 몇 가지 이용성 관련 문제점을 지적하였다.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 2004년도 추계학술발표회 발표논문집
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• pp.229-230
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• 2004

• 한국자동차공학회논문집
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• 제6권3호
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• pp.1-10
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• 1998

In this paper, we investigated the improvement of characteristics of knock, emission and fuel consumption rate by optimizing the location and size of water transfer holes in cylinder head gasket without change of engine water jacket design itself. The cooling system was modified in the direction of reducing the metal temperature in the head and increasing the metal temperature in the block. The optimization of water transfer holes in cylinder head gasket was obtained by "flow visualization test". The water transfer holes were concentrated in front side of the engine in order to reduce thermal boundary layer in the water jacket of No. 2 and No. 3 combustion changer in the cylinder head, which would have a large knock intensity, and increase thermal boundary layer in the water jacket of the cylinder block. When the modified coolant flow pattern was applied as proposed in this paper, the knock characteristic was improved. The spark timing was advanced up to 2$^{\circ}$ in low and middle speed range at a full load. In addition, HC emission at MBT was reduced by 5.2%, and the fuel consumption rate was decreased up to 1% in the driving condition of 2400 rpm and 250 KPa. However, since this coolant flow pattern mentioned in this paper might deteriorate the performance of vehicle cooling system due to the coolant flow rate reduction, a properly optimized point should be obtained. obtained.

• 공학교육연구
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• 제18권4호
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• pp.34-44
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• 2015

Mathematical, spatial, and verbal abilities are important for future engineers to succeed in the STEM disciplines. The purpose of the study is to assess engineering students' spatial abilities and analyse the relationship with mathematical achievement, verbal achievement, and gender. On the mental rotation tests, 65% of male students demonstrated a substantial level of spatial abilities. But only 30% of female students exhibited spatial skills at the same level as their male colleagues. The correlations between mathematical - spatial - verbal abilities are found to be negligible. When spatial visualization ability was plotted according to the mathematical achievement level, there was no difference in the mean spatial abilities score. But when mathematical achievement score was plotted according to the spatial abilities, there was a noticeable difference. Regression analysis confirmed that female students' mathematical achievement increased as spatial abilities improved. This phenomenon was not observed for male students. It's because male students' spatial ability already contributed to their mathematics achievement. So spatial ability can be regarded as one factor for the gender differences in mathematics achievement. The gender gap on spatial abilities and math achievement is large among high achieving students. For example, there was a 4.3 to 1 male - female ratio and 3.4 to 1 male - female ratio among students scoring 99th percentile in spatial visualization test and scholastic aptitude test-math.

• Wind and Structures
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• 제18권5호
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• pp.511-528
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• 2014

The characteristics of wake galloping phenomenon for two parallel/unparallel circular cylinders were investigated via wind tunnel tests. The two cylinders were initially deployed in parallel and wake galloping phenomena were observed by varying the center-to-center distance. The effect of an unparallel arrangement of two cylinders was next investigated by fixing the spacing ratio of one side of the cylinders at 5.0D and the other side at 3.0D, in which D represents the diameter of the cylinder. For the unparallel disposition, the 5.0D side showed a small, limited vibration while the 3.0D side produced much larger amplitude of vibration, resulting in a rolling motion. However, the overall amplitude appeared to decrease in unparallel disposition when compared with the amplitude of the 3.0D - 3.0D parallel case. This represents the mitigation effect of wake galloping due to the unparallel disposition between two cylinders. Flow visualization tests with particle image velocimetry were conducted to identify flow fields between two cylinders. The test results demonstrate the existence of a complex interaction of the downstream cylinder with the shear layer generated by the upstream cylinder. When the spacing ratio was large enough, the shear layer was not observed and the downstream cylinder showed only limited random vibration.

• 한국콘텐츠학회논문지
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• 제1권1호
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• pp.68-73
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• 2001

웹 환경에서 사용자는 다른 어떠한 인터페이스 환경에서보다도 더 적극적이고 자유로운 인터랙션을 하고 있으며 따라서 웹 사이트 개발에 있어서 사용자 인터페이스 환경을 고려하는 것은 매우 중요하다. 본 연구에서는 웹 인터페이스 환경과 그 특징에 대해 살펴보고 현재 활용되고 있는 사용성 평가 기법들을 정리한 후, 이를 기반으로 웹에서의 사용자들의 다양한 반응과 양상을 효과적으로 시각화하고 분석/평가할 수 있는 도구를 개발하였다. 또한 개발된 시각화 도구를 한 인터넷 허브 사이트의 사용성 평가 과정에 적용해 보고 그 결과에 대해 논의함으로써 웹에서의 사용 감성의 시각화와 평가를 위한 실질적인 방법을 제안하고자한다.

• 한국소음진동공학회논문집
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• 제21권8호
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• pp.774-780
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• 2011

Recently, customers have been concerned about vehicle NVH depending on vehicle designing and manufacturing technologies development. In choosing vehicle, vehicle NVH is becoming the most important factor to customers. Especially, a seat is the final stage of vibration transfer path to passengers from all sources of vibration like engine, transmission and etc. And seat is the nearest component from driver's ear. For this reason, seat is the most important component that directly related to ride comfort for passengers. And driver can be influenced sensitively by BSR caused by seat. Thus, evaluating the vibration characteristics of vehicle seat and BSR caused by vehicle seat is necessary to reduce the seat BSR. The rattle noise occurred from seat has evaluated through sound source visualization and multi-dimensional spectral analysis - coherence function technique in this paper. Vibration characteristics of the seat has verified through modal test.

• 한국가시화정보학회지
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• 제10권3호
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• pp.16-20
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• 2012

In the past decades, extensive studies on convection heat transfer on internal flow have been conducted by using high specific surface area, by increasing heat transfer coefficient and swirl flow, and by improving the transport properties. In this study, we applied a tangential slot swirl generator to improve heat transfer in a horizontal circular copper tube. The Al-Mg particles (approximately $100{\mu}m$ to $130{\mu}m$) were employed for this experimental work. The copper tube was heated uniformly by winding a heating coil with a resistance of 9ohm per meter for heat transfer. Using Al-Mg particles, experiments were performed in the Reynolds number range of 5,000 to 13,130, with and without swirl. Experimental data transfers or comparisons between Nusselt numbers with and without swirl along the test tube and Reynolds numbers are presented. The Nusselt number is improved by increasing Reynolds numbers or swirl intensities along the test tube.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 춘계학술대회논문집B
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• pp.795-800
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• 2000

A CCFL(Counter Current Flow Limit) test have been performed in narrow annular gaps with large diameter, because it has been confirmed that the CCFL phenomena affected the critical power in hemispherical narrow gap geometries from the SONATA(Simulation Of Naturally Arrested Thermal Attack)-IV (In-Vessel)/VISU(Visualization)-II experiments. The objectives of the CCFL experiments are to investigate the small gap sizes(1, 2mm) effect on CCFL under the large diameter condition and to confirm the findings of the VISU-II study that global dryout in hemispherical narrow gaps was induced by the CCFL. The test section was made of acrylic resin to allow visual observation on the two-phase flow behaviors inside annular gaps. It was observed from visualization that a part of water supplied was accumulated in the upper plenum and a significant increase in the differential pressure across the gap was occurred, which was the definition of the CCFL occurrence in this experimental study. From the experimental results in annular gap with large diameter it can be known that an increase in the differential pressure was not big at small air flow-rates. When the CCFL was occurred, the differential pressure across gaps was increased significantly and a water accumulated in the upper plenum. The occurrence of CCFL was correlated using the Wallis parameter.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회B
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• pp.2434-2439
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• 2008

This paper was studied on the cavitation instability of a Solution Pump Inducer in an absorption chiller-heater. Inlet pressure of LiBr and rotational speed at nominal mode are 2,800 Pa and 3,500 rpm respectively. Due to the marginal operation of available NPSH, the cavitation performance of the inducer is critical for the stable operation without the deterioration of head performance. In the study, cavitation performance and its mode of instability was investigated experimentally. Water was used as the working fluid and the test inducer was scaled up as 1.75 times for detail measurements and flow visualization. Inlet pressure was controlled by a vacuum pump. This research focused on types of cavitation instability and phenomena to investigate the possibility of harmful damage due to cavitation instability. Casing wall pressure and instantaneous inlet pressure was measured to observe the unsteady flow characteristics. Through the visualization and spectrum analysis of pressure, the occurrence region and intensity of asymmetric cavitation and cavitation surge are analyzed in the test inducer.