• Journal of Korean Society of Coastal and Ocean Engineers
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• v.20 no.4
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• pp.333-341
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• 2008

A remote sensing technique to identify trajectories of breaking waves in the surf zone using oblique digital nearshore videos is proposed. The noise arising from white foam induced by wave breaking has hindered accurate remote sensing of wave properties in the surf zone. For this reason, this paper focuses on image processing to remove the noise and wave trajectory identification essential for wave property estimation. The nearshore video imagery sampled at 3 Hz are used, covering length scale(100 m). Original image sequences are processed through image frame differencing and directional low-pass image filtering to remove the noise characterized by high frequencies in the video imagery. The extraction of individual wave crest features is conducted using a Radon transform-based line detection algorithm in the processed cross-shore image timestacks having a two-dimensional space-time domain. The number of valid wave crest trajectories identified corresponds to about 2/3 of waves recorded by the in-situ sensors.

• Korean Journal of Remote Sensing
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• v.27 no.4
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• pp.403-410
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• 2011

Consistent observation with high temporal and spatial resolution is required for an efficient monitoring of coastal environments. Remote monitoring system installed on the ground is capable of simultaneous observation of wide coastal area and consistent observation with high frequency, which a small number of in-situ measurements cannot manage. This paper studies two typical ground based coastal monitoring system, marine radar and camera system. Marine radar can produce time series of frequency spectrum by integrating wave number spectrum calculated from spatial and temporal variation of waves in the radar image. The time averaged radar images of waves can analyze wave breaking zone, rip currents and location of littoral bars. Camera system can observe temporal variation of foam generation originated from coastal contamination as well as shoreline changes. By extracting the part of foams from rectified images, quantitative analysis of temporal foam variation can be done. By using the two above systems of different characteristics, synergetic benefit can be achieved.

• Proceedings of the Korean Fiber Society Conference
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• 1987.06a
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• pp.46-46
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• 1987

• Proceeding of EDISON Challenge
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• 2016.11a
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• pp.4-8
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• 2016

본 연구에서는 플라잉 디스크를 이용하여 회전 운동의 유무에 따른 공력특성의 변화를 비교 분석하였다. 회전 운동이 발생하면 표면에 비대칭적으로 압력이 분포하기 때문에 롤링 모멘트가 발생하고 마그너스 효과로 측력이 발생하고 피칭모멘트, 회전감쇠모멘트가 발생하고 롤 안정성이 증가한다.

• Korean Journal of Food Science and Technology
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• v.25 no.2
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• pp.109-117
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• 1993

To investigate the effects of sodium alginate, gum karaya and gum arabic on the foaming properties of sodium caseinate, surface tension, specific viscosity, turbidity, foaming ability and foam stability of the caseinate solution with added gums were examined. Surface tensions of the 5%(w/v) protein solutions containing gums at pH 7.0 and 8.0 were $43.7{\sim}44.7dyne/cm$ and $43.6{\sim}44.0 dyne/cm$, respectively. Specific viscosities of the solutions with 0.2 and 0.3% sodium alginates were 15.6 and 39.1 at pH 7.0 (control, 2.8), and 12.1 and 8.2 at pH 8.0 (control, 2.6), respectively. Turbidities were $69.5{\sim}74.0$ at pH 7.0 and $68.0{\sim}72.5$ at pH 8.0. The optimum conditions for foaming ability of the solutions were 0.1% conc. and 15 min whipping in addition of sodium alginates; 0.2% conc. and 20 min whipping in gum karaya; 0.1% conc. and 10 min whipping in gum arabic. For foam stability optimal concentrations were 0.3% in sodium alginate and gum karaya at pH 7.0 and 0.2% at pH 8.0. Addition of sodium alginates was most effective to increase foam stability of the solution, but was not effective to increase foaming ability. At same pH, surface tensions and turbidity of the solutions were related to foaming ability and specific viscosities were related to foam stability.

• Korean Journal of Food Science and Technology
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• v.24 no.5
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• pp.482-491
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• 1992

Experiments were conducted to elucidate the effects of pH change and sodium alginate, gum karaya and gum arabic on the foaming properties of soy protein isolate (SPI). The surface tensions of SPI solution (5%) adding to gums at pH 4.0 and 5.0, near the isoelectric point (pH 4.5) were higher than those at pH 7.0 and 8.0. Specific viscosity of the solutions adding to gums (0.1, 0.2 and 0.3%) at pH 7.0 and 8.0 were $3.6{\sim}51.8$ and $4.0{\sim}51.2$, respectively. In cases of addition of sodium alginates specific viscosity were predominantly increased, while those of gum arabic did not almost increase. Addition of gums reduced the overrun, but it stabilized the foams, especially those of sodium alginates (0.2%) increased the foam stability at pH 5.0, 7.0 and 8.0 by 57, 413 and 315%, respectively. Foaming ability, foam stability and heat stability of the foam were significantly (p<0.05) affected by changing pH. There was a tendency to increase the foaming ability according to the decrease of surface tension. Specific viscosity was also important in foam stability and heat stability.

• The Korean Journal of Financial Management
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• v.10 no.2
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• pp.53-81
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• 1993

본고에서는 부동산 가격의 상승과 기업가치의 관제를 이론적으로 규명하고 그에 관한 실증분석의 결과를 제시한다. 우선 이론적인 분석에서는 거품가격의 형성에 의하여 야기되는 부동산 가격상승 기대는 기업의 미래 성장기회에 대한 가치손실을 야기하므로 부동산 가격상승 기대에 따른 기업가치의 변화는 기업의 보유 부동산 가치의 상승에 미치지 못할 것으로 분석하였다. 또한 이러한 성장기회의 가치 상실은 부채에 의한 자금조달이 높을수록 더욱 커질 것으로 분석되었다. 이에 대한 실증분석의 결과, 우선 87-91년의 연도별 횡단면 분석에서는 기업의 부동산 보유 비율이 주식수익률에 큰 영향을 미치지 않는 것으로 나타났다. 그러나 부채비율의 과다에 따라 표본을 분류하여 분석을 하였을 때에는 고부채 기업일수록 부동산 보유 변수에 대한 회귀제수가 전반적으로 낮게 나타나 부채사용이 높을수록 성장기회 가치상실이 클 것이라는 이론적인 가설을 지지하였다. 이러한 결과는 기업의 규모별 분석에서는 관찰되지 않았다. 따라서 주식수익률의 부동산 보유 효과는 규모별 효과에 비하여 부채비율별 효과가 좀 더 뚜렷한 효과로 간주되었다.

• Proceedings of the Korea Inteligent Information System Society Conference
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• 2005.05a
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• pp.295-301
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• 2005

1995년부터 급격히 발전하기 시작한 전자상거래는 2000년 후반에 들면서 커다란 전환을 맞이하게 되었다. 인터넷 기업에 대한 거품이 제거되면서 주가가 폭락하였고, 전자상거래에서 과연 수익을 얻을 수 있는 모델은 무엇인지에 대한 의문이 제기되기 시작하였다. 이러한 시기에 최근 게임산업은 세계 미디어 시장에서 큰 비중을 자치하는 21세기형 산업으로 부상하고 있으며, 또한 많은 비즈니스 수익모델 중에서 수익을 제공할 수 있는 비즈니스 모델로 급부상하고 있다. 이에 본 연구에서는 온라인 게임 사용자들의 충성도에 영향을 주는 요인들에 대한 인과관계를 연구하고자 하였다. 특히 게임의 중독이 이러한 인과관계에 어떤 매개효과가 있는지를 검정해 보고자 하였다.

• Proceedings of the Korean Society of Computer Information Conference
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• 2022.01a
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• pp.345-348
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• 2022

본 논문에서는 유체 시뮬레이션(Fluid simulation)중 화염에서 표현되는 불똥 입자(Fire-flake particle)의 생성, 움직임과 삭제를 효율적으로 학습하고 표현할 수 있는 인공지능 기법에 대해 소개한다. 유체 시뮬레이션을 계산하기 위해서는 일반적으로 수치해석학과 같은 학문의 이해가 필요하며 불똥이나 거품과 같은 유체의 2차 효과(Secondary effect)는 기반유체(Underlying fluids)를 통해 추출되기 때문에 복잡하고 계산양이 많아진다. 이러한 문제를 완화하고자 본 논문에서는 인공신경망을 이용한 분류 모델 학습을 통해 격자 내에서 표현되어야 하는 불똥 입자의 생성을 학습하고, 다항 회귀 모델 학습을 통해 불똥 입자의 움직임을 예측한다. 또한, 불똥 입자가 삭제되어야하는 상태를 네트워크 학습을 통해 얻어내며, 수명(Lifespan) 임계값 조절하여 다양한 장면에서 불똥을 제어할 수 있다. 결과적으로 화염의 움직임을 기반으로 불똥의 움직임을 복잡한 수학식이나 디자이너에게 의존하지 않고 인공지능 학습을 통해 쉽게 제어하고 예측하는 결과를 보여준다.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.32 no.5
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• pp.542-549
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• 1999

The hydrothermal extracts were produced from fish head and their functional properties were investigated. The extracts exhibited an antioxidative effect and synergistic effect with $\alpha$-tocopherol by measuring peroxide values. The $5\%$ solution showed more antioxidative effect than $1\%$ solution. The extracts showed cryopropective effect, but the effect was less than sucrose. The solubility of the extracts was over $70\%$ in the all range of pH, and its lowest solubility was shown in pH 3.0. The extracts exhibited an emulsifying activity less than sugar ester (EAI=34.72) and little higher than or similiar to egg white (EAI= 14.69). The extracts showed a relatively high foam activity. The osmolality of the hydrothermal extracts at $1.0\%$ concentration were 23$\~$31 mOsmole which were much lower than 317 mOsmole at $1\%$ NaCl.