• Journal of the Korean GEO-environmental Society
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• v.17 no.11
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• pp.23-33
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• 2016

This study evaluated the stability and deformation subsea foundation after implementation of the contaminant isolation method by covering the contaminated materials using Zeolite and sands under subsea condition. The appropriate contaminant adsorption materials used in this study was selected as Zeolite based on the existing research results due to its efficiency. Safety (or stability) was evaluated by calculation and to analyze deformation after completing the contaminant isolation method. The minimum safety factors from slope stability analyses results were 30.1 and 11.2 depending on subsea submerged conditions and the amount of the maximum primary consolidation settlement from consolidation analysis results was 209.2 mm. In addition, change of consolidation amount with increasing consolidation time was evaluated based on consolidation degree.

• The Korean Journal of Nuclear Medicine Technology
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• v.13 no.1
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• pp.116-119
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• 2009

Background: Preanalytical factors can affect reliability of hormone assay results. Adrenocorticotropic hormone (ACTH) in blood is considered highly unstable because of proteolytic degradation, so storage of blood samples on ice until analysis is recommended. In clinical practice, however, this procedure may present logistical problems because most samples for ACTH measurement must be shipped from the place of sample collection to the laboratory. Therefore, we studied the impact of time and temperature before plasma separation and analysis on the results of ACTH assays. Methods: A total number of 22 patients were enrolled in this study. We obtained 2 blood samples. ACTH concentrations were 35~126 pg/mL. ACTH concentrations were measured by immunoradiometric assay (IRMA) using commercial kits (CIS Biointernational, Gif-sur-Yvette, France). Results: ACTH levels showed a significant difference between the samples of $22^{\circ}C$ EDTA and $4^{\circ}C$ EDTA. Measured ACTH concentrations significantly decreased with time before freezing at $-20^{\circ}C$. ACTH levels showed no significant difference between the groups of after storage for 24 hr without centrifugation at $22^{\circ}C$ and $4^{\circ}C$. Conclusion: We recommend that blood samples be obtained on pre-chilled EDTA collection tubes. The shortest possible time between sample collection and processing is always the best laboratory practice.

• Proceedings of the Korean Society for Food Science of Animal Resources Conference
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• 2005.10a
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• pp.177-181
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• 2005

근원섬유 단백질에 카제인염을 첨가함으로써 유화안정성이나 보수력을 증진시킬 수 있으나 가제인염은 열에 안정성이 떨어지는 단점을 가지고 있다. TGase가 이러한 카제인염의 단점을 보완해주는지 알아보기 위해 열량분석기와 전기영동을 이용하여 단백질의 변화를 측정하였다. 열량분석기의 경우 근원섬유 단백질과 카제인 염 단백질의 상호교차결합을 TGase의 첨가유무에 따라 실시하였으며 그 결과 TGase의 첨가는 각 단백질 열량변화가 나타나는 온도를 변화시켰으며 배양시간을 증가할수록 각 단백질별 열량변화의 차이를 보였고 peak의 크기에도 차이를 보였다. 또한 전기영동의 경우 MFP, SC, MFP:SC의 1:1 혼합액을 각각을 TGase 첨가한 것과 하지 않은 것을 비교한 결과, TGase의 첨가는 고분자 polymer를 만들어줌으로써 두 단백질간의 상호작용에 촉매제로써 작용한다는 것을 확인하였다.

• Proceedings of the Korean Information Science Society Conference
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• 2006.10d
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• pp.50-55
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• 2006

저전력 연산능력과 무선통신 기능을 포함한 경량의 센서노드들로 구성된 무선 센서네트워크는 자연 환경의 모니터링에서 군사적인 목적에 이르기까지 다양한 어플리케이션을 창출 할 수 있다. 그러나, 다수의 저가 무선 노드를 배치해야 하는 센서네트워크의 특성상 안정성이 높은 고가의 부품을 사용할 수 없어, 이에 대한 보완 방안에 대한 연구가 활발히 진행 중이다. 특히, 무선 노드들 간의 시간동기화는 가용 무선 대역폭이 적은 무선 센서 네트워크에서 TDMA 스케줄링등의 기술을 구현하기 위한 필수적인 기반기술로서 네트워크 특성을 고려한 새로운 동기화 기법을 요구하고 있다. 본 논문에서는, 무선센서노드의 특성을 파악하고 시간 동기화 수행 시 발생할 수 있는 오차요인을 분석하여, 넓은 지역에 산발적으로 분포되는 무선 센서네트워크의 특성을 보완할 수 있는 새로운 시간동기화 기법을 제안한다.

• Journal of the Korean Institute of Intelligent Systems
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• v.16 no.2
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• pp.179-184
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• 2006

An intuitive understanding of the dynamic pattern generation in asymmetric networks may be considered an essential component in developing models for the dynamic information processing. It has been reported that the neural network with cyclic connections generates multiple limit cycles. The dynamics of discrete time network with cyclic connections has been investigated intensively. However, the dynamics of a cyclic connection neural network in continuous-time has not been well-known due to the considerable complexity involved in its calculation. In this paper, the dynamic behavior of a continuous-time cyclic connection neural network, in which each neuron is connected only to its nearest neurons with binary synaptic weights of ${\pm}1$, has been investigated. Furthermore, the dynamics and stability of the network have been analyzed using a piece-wise linear approximation.

• Proceedings of the Korea Multimedia Society Conference
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• 2001.06a
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• pp.219-222
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• 2001

본 연구의 내용은 실시간 서비스 트래픽, 즉 보장형 서비스를 위한 스케줄링 알고리즘들에 대한 성능분석에 대한 연구이다. 특히 실시간 데이터 전송의 경우, 작은 지연 시간을 요구하면서 안정된 QoS를 요구하고 있다. 기존에 알려진 FQ, WFQ, WF2Q, Virtual Clock 스케줄링 알고리즘들을 사용해서 대기 큐의 수학적 모델이 아닌 시뮬레이션 도구를 사용해서, 지연에 민감한 보장형 서비스 트래픽에 대한 시간 복잡도, 공정성, 처리율 측면으로 성능을 분석하였다.

• Proceedings of the Korea Water Resources Association Conference
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• 2016.05a
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• pp.528-528
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• 2016

신뢰성 있는 수문순환모의를 위해서 다양한 수문모형이 사용되고 있다. 그 중 대표적인 수문모형인 강우-유출 모형은 유역에 발생한 강우에 반응하는 유출특성을 평가하는데 이용된다. 강우-유출 과정은 강우량, 유출량, 도달시간 및 토양수분 등과 연관된 매개변수들의 최적화 과정을 통해서 추정된다. 하지만 동일한 강우사상이라도 다양한 매개변수들로 인하여 상당히 다른 유출패턴을 나타내기 때문에 수문순환 과정을 정확히 모의하기 위해서 강우-유출 분석시 불확실성 분석이 필수적으로 요구된다. 불확실성 분석은 통계학에서도 쉽지 않은 연구내용으로서 가장 진보된 불확실성 분석기법인 Bayesian 기법은 매개변수의 추정과 불확실성 분석을 동시에 수행할 수 있는 방법으로 매개변수들은 사후분포(posterior distribution)로 귀결되며 최종적으로 확률분포형의 형태를 가진다. 본 연구에서는 국내외적으로 널리 사용되는 단기유출 모형 HEC-1 모형에 Bayesian 기법을 연계하여 대상유역의 도달시간, 저류상수 및 CN No. 최적화 및 불확실성 평가를 수행하였다. 연구결과 Bayesian 기법을 통한 매개변수 최적화 결과는 안정적인 수렴결과를 확인하였으며, 확률강우량을 입력자료로 사용하여 산정된 빈도별 홍수수분곡선의 불확실성 분석을 통하여 향후 수공구조물의 위험도 분석 및 수자원계획 수립시 유용한 자료로 사용될 것으로 판단된다.

• Journal of Environmental Policy
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• v.12 no.4
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• pp.93-117
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• 2013

We analyze the optimal hedge ratio and hedge effectiveness with different periodic times between spot and futures on EUA and CER based on EU-ETS. The Main finding are as follows. The first, hedging model which considers the time-varying variance is not more accurate than non-time-varying hedging models. The second, optimal hedge ratios are different even though hedge effectiveness is similar for the hedging purpose. The third, hedge effectiveness has uncertainty if hedge period is short. In case of EUA it needs to over 6 weeks and CER needs to over 7 weeks. The fourth, cross hedge with CER futures is not suitable for profit ratios.

• Korean Journal of Food Science and Technology
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• v.37 no.2
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• pp.178-182
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• 2005

Basic optimal extraction condition and stability data were determined for prediction of usefulness of olive leaf as functional food material. Solid contents of olive leaf extracts increased with increasing extraction temperature and ethanol content, and was the highest (38%) under $85^{\circ}C$, 80% ethanol, and 5 hr treatment conditions, Total phenol contents and electron-donating abilities of olive leaf extracts also increased with Increasing ethanol content, and were the highest under $25^{\circ}C$, 80% ethanol, and 1 hr treatment conditions, then slightly decreased during storage at $25,\;55,\;and\;85^{\circ}C$. Olive leaf extract showed high stability under acidic storage condition, while low under alkalic condition.

• Korean Journal of Materials Research
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• v.10 no.6
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• pp.403-408
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• 2000

The Al-Cr-Zr composite metal powders were prepared by mechanical alloying and consolidated by vacuum hot pressing. The microstructural characteristics and the thermal stability of the MA Al-Cr-Zr alloys were evaluated by means of microhardness measurement, XRD and TEM in order to develop high temperature, high strength aluminum alloys. The mechanical alloying was conducted in attritor with 300rpm for 20 hours. The density of the vacuum hot pressed Al-Cr-Zr alloy reached at 97% of theoretical one. After exposing at $300^{\circ}C$ for 100 hours, there is almost no variation in hardness change of the MA alloys. Even after exposing at $ 500^{\circ}C$ for 100 hours, the hardness of the alloy was decreased within 6% of the initial value. The fine stable $Al_3Zr\;and\; Al_{13}Cr_2$ intermetallics were formed at the stage of consolidation and heat treatment in aluminum matrix. The good thermal stability of the MA Al-Cr-Zr alloy can ab attributed to the role of the dispersoids, inhibiting grain growth of nanocrystalline, and the final grain size after heat treatment was less than 150nm.