• Korean Journal of Optics and Photonics
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• v.10 no.4
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• pp.279-282
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• 1999

We designed and fabricated a single polarizer mode bistable twisted nematic liquid crystal display by employing a wide-band λ/4 retardation film to enhance the dark state property. We theoretically and experimentally confirmed the necessity of a wide- band λ/4 retardation film in a single polarizer mode. We obtained brighter image than previous reflective BTN LCDs.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.5B
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• pp.405-412
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• 2006

In this paper, we present an efficient method for simulating massively virtual clients in an online game environment. Massively multi-player online games and other multi-user based networked applications are becoming more attractive to the gamer players. Such kind of technology has long been researched in the area called Networked Virtual Environments. In the game development process, a set of beta tests is used to ensure the stability of online game servers. A set of testing processes consumesa lot of development resources such as cost, time, and etc. The purpose of VENUS system is to provide an automated beta test environment to the game developers to efficiently test the online games to reduce development resources.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.19 no.6
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• pp.521-528
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• 1986

In this paper, proteolytic activity of the tissue extracts from the internal organs such as alimentary canal, pancreas, pyloric caeca, stomach, liver and spleen of mackerel, Scomber japonicus, and sardine, Sardinops melanosticta, was compared with each other under the optimum reaction condition. The proteinases distributed in alimentary canal, pancreas, pyloric caeca and spleen were active in alkaline pH range, but those in stomach were shown the activity in acid pH range, furthermore those in liver were exhibited the activity in acid, neutral and alkaline pH range. The proteinases distributed in the internal organs of both fish were stable at the heat treatment of $45^{\circ}C$ for 5 minutes. The proteinases from stomach and pyloric caeca of the two fish and those from pancreas of sardine were less stable than those from any other internal organs of both fish. Whereas the proteinases from spleen and neutral proteinases from liver were shown to be stable by the heat treatment at $55^{\circ}C$ for 5 minutes. The proteinases from pyloric caeca of both fish, and stomach, pancreas and spleen of mackerel were stable during the whole storage days at $5^{\circ}C$, but the other proteinases were slowly inactivated after 14 days of storage. The enzymes were seemed to be more stable in the storage at $-15^{\circ}C$ than at $5^{\circ}C$.

• Journal of Digital Convergence
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• v.19 no.2
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• pp.61-69
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• 2021

The military pension deficit is increasing due to an increase in the average life expectancy and pension option rate, and a significant reason for this is estimated to be a continued increase in the number of military pension recipients. In terms of the soundness of military pension finances, this paper uses the Markov chain model to validate the stability of the military group, suggesting the direction of future military pension system in terms of the ratio of pension receipts to employees, and verifying the feasibility of the method applied through verification. Through this paper, we have confirmed that the initial 45,270 military personnel converge to 43,141 after a certain period of time and reach a stable state, which is expected to help us to estimate the long term size of military pension recipients to confirm the direction of national financial support. Military man who are eligible for pensions for more than 20 years have a relatively low rate of turnover or retirement compared to ordinary private groups, making it easier to define their status and simplify state transition probabilities. Therefore, it is expected that the sustainability of the military pension will be confirmed from a long term perspective by viewing the military group as a system and applying it to the Markov chain model by checking the probability of transfer of status such as promotion, maintaining the current grade, and retirement during the period.

• Journal of the Korean Society of Food Science and Nutrition
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• v.13 no.1
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• pp.57-63
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• 1984

This study was designed to compare the quality characteristics of freeze and spray dried red ginseng extract powders(RGEPs) by drying methods, which have been required to maintain the stability for the quality. Chemical compositions, major ginsenoside contents and color intensities of these Products were compared by drying conditions. The moisture absorption rates and optical densities also were compared during storage under maltreatment conditions of a various relative humidities (75, 86and 92 RH) and two different temperatures (37 and $50^{\circ}C$). It was found that decreases of total major ginsenosides contents in freeze and spray dried RGEPs were 5.4 % to 6.7 % during storage for 6 months at $37^{\circ}C$, 75 % RH. When these products packaged with inner seal of Al-foil laminate paper (Al-foil; 9 ${\mu}m$) were stored for 6 months at $37^{\circ}C$, 75 % RH. the moisture absorption rates of freeze and spray dried RGEPs were ranged 42 % to 82 %, 8 % to 16 %, respectively. In storage for 6 months at $37^{\circ}C$, 86 % RH, spray dried RGEP was higher in brown pigment($400{\sim}490nm$) than freeze dried RGEP while freeze dried was higher in pyrazine (278 nm), HMF and furfural (285 nm) than spray dried RGEP. It was found that RGEPs showed a strong anti-oxidative activity by electron donating ability to DPPPH, but there was no significant difference between freeze and spray dried RGEPs.

• The Journal of the Korea Contents Association
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• v.12 no.9
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• pp.357-368
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• 2012

The purpose of this study is to empirically examine the impact of enterprise R&D investment on international trade in Korea under the new Normal Era. In order to test whether the time series data of trade variables are stationary or not, we put in operation unit root test and cointegration test. Based on VECM (Vector Error Correction Model), we also apply impulse response functions and variance decomposition to estimate the dynamic effects in the short-run and long-run. The results show that the relationship between enterprise R&D investment and international trade (export and import) exists in the long-run as well as in the short-run. The results of applying impulse response functions and variance decomposition also indicate that the impact of enterprise R&D investment on international trade is positive, and a significant portion of fluctuations in the trade variable is explained by enterprise R&D investment. Therefore, enterprise R&D investment must be continuously increased to improve economic growth with promoting trading competition power in Korea under the new Normal Era.

• The Korean Journal of Applied Statistics
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• v.32 no.1
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• pp.69-81
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• 2019

We consider bivariate long range dependent (LRD) time series forecasting using a deep learning method. A long short-term memory (LSTM) network well-suited to time series data is applied to forecast bivariate time series; in addition, we compare the forecasting performance with bivariate fractional autoregressive integrated moving average (FARIMA) models. Out-of-sample forecasting errors are compared with various performance measures for functional MRI (fMRI) data and daily realized volatility data. The results show a subtle difference in the predicted values of the FIVARMA model and VARFIMA model. LSTM is computationally demanding due to hyper-parameter selection, but is more stable and the forecasting performance is competitively good to that of parametric long range dependent time series models.

• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2012.03a
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• pp.52-52
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• 2012

Poly(phenylene sulfide)(PPS)는 내열성 및 내화학성이 뛰어난 고분자 소재로, 대표적인 엔지니어링 플라스틱 중 하나이다. PPS는 벤젠 링에 황원자가 파라 치환 형태로 교대로 존재하는 결정성 고분자이며, 다른 대부분의 고성능 섬유고분자가 용융되지 않는 것과는 달리 용융되는 열가소성 소재이다. PPS는 높은 내약품성과 열에 대한 장기적인 안정성을 나타내고, 방염제 첨가 없이도 방염화가 가능하며, 전기 절연성이 뛰어나고, 형태안정성도 우수하다. 또한 $200^{\circ}C$ 이하에서는 어떤 용매에도 용해되지 않으며, $200^{\circ}C$ 이상에서도 몇 가지 방향족 화합물에만 제한된 범위 내에서 용해되는 우수한 내약품성을 나타낸다. PPS의 내열성을 더욱 우수하게 하기 위해 고분자 사슬을 가교할 수 있다. 가교에는 열처리 또는 감마선, 전자선, 자외선 조사를 이용할 수 있는데 열에 의한 가교는 균일한 열전달과 고온이 필요하며 감마선 및 전자선 조사는 설비의 고비용과 방사선 노출 위험으로 인해 비친환경적이다. 반면에 자외선 조사법은 다루기 쉽고 비용이 적게 들고 친환경적인 장점을 가진다. 본 연구에서는 PPS film의 열안정성을 향상시키기 위해 자외선 조사를 이용하여 PPS film의 광가교를 수행하였다.

• Proceedings of the Korea Water Resources Association Conference
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• 2015.05a
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• pp.155-155
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• 2015

태풍과 집중호우와 같은 극치사상은 치수적인 측면 뿐 아니라 안정적인 용수공급과 수자원의 확보, 수질 및 생물다양성 확보, 생태계의 안정성 및 복원력 향상 등에 매우 중요하나, 국외에 비해 국내연구는 매우 부족한 실정이다. 또한, 장기간의 수문 및 기상자료의 변동 및 경향, 예측 등의 많은 연구들로 인해 사실상 현실화가 된 기후변화 등의 이유로 극한 호우사상이 해를 거듭할수록 증가할 것으로 전망되고 있어 이에 대한 위험성이 대두되고 있는 실정이다. 한반도의 극치호우사상의 변화 및 양상을 보다 심도있게 평가하기 위해 한반도에 영향을 미치는 태풍 및 집중호 우을 분리하는 기법을 개발 및 적용하여 각 호우원인별 특성 변화 및 경향 분석을 수행하였으며, 한반도의 호우원인별 극치 호우사상에 영향을 미치는 해수면온도와 관련된 El Nino 패턴과 수문기상인자 등과의 상관성 분석을 수행하였다. 마지막으로 기후변화가 한반도 극치호우사상에 미치는 영향을 정량적으로 평가하고 비정상성빈도해석을 통해 미래확률강우량을 산정하였다. 본 연구의 분석결과는 향후, 미래 한반도 영향 태풍 및 집중호우의 강도 및 규모를 고려한 지역 맞춤형 치수정책 및 방재대책 수립에 대한 기초자료로 활용가능할 것으로 판단된다.

• Journal of the Korean Geotechnical Society
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• v.19 no.6
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• pp.189-206
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• 2003

During tunnel excavation in urban area a systematic monitoring is important for the purpose of determination of support type and quantity, as well as for the control of stability of both surface structures and the tunnel itself due to the frequently, and in many cases, abruptly changing ground condition. In Austria absolute displacement monitoring methods have replaced relative displacement measurements by geodetic methods to a large extent. Prompt detection of weak ground ahead of the tunnel face as well as better adjustment of excavation and support to the geotechnical conditions is possible with the help of the improved methods of data evaluation on sites. Deformation response of the ground to excavation starts ahead of the tunnel face, therefore, the deformation and state of the tunnel advance core is the key factor of the whole deformation process after excavation. In other words, the rigidity and state of the advance core play a determining role in the stability of both surface structures and the tunnel itself. This paper presents the results from detailed three-dimensional numerical studies, exploring vertical displacements, vector orientations and extrusions on tunnel face during the progressive advancement for the shallow tunnel in various geotechnical conditions.