• Structural Engineering and Mechanics
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• v.66 no.1
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• pp.75-84
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• 2018

This study presents the reliability-based analysis of nonlinear structures using the analytical fragility curves excited by random earthquake loads. The stochastic method of ground motion simulation is combined with the random vibration theory to compute structural failure probability. The formulation of structural failure probability using random vibration theory, based on only the frequency information of the excitation, provides an important basis for structural analysis in places where there is a lack of sufficient recorded ground motions. The importance of frequency content of ground motions on probability of structural failure is studied for different levels of the nonlinear behavior of structures. The set of simulated ground motion for this study is based on the results of probabilistic seismic hazard analysis. It is demonstrated that the scenario events identified by the seismic risk differ from those obtained by the disaggregation of seismic hazard. The validity of the presented procedure is evaluated by Monte-Carlo simulation.

• Journal of Korea Water Resources Association
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• v.49 no.4
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• pp.283-291
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• 2016

As the infrastructures and populations are the condensed in the mega city, urban flood management becomes very important due to the severe loss of lives and properties. For the more accurate calculation of runoff from the urban catchment, hourly or even minute rainfall data have been utilized. However, the time steps of the measured or forecasted data under climate change scenarios are longer than hourly, which causes the difficulty on the application. In this study, daily rainfall data was disaggregated into hourly using the stochastic method. Based on the historical hourly precipitation data, Gram Schmidt orthonormalization process and K-Nearest Neighbor Resampling (KNNR) method were applied to disaggregate daily precipitation into hourly. This method was originally developed to disaggregate yearly runoff data into monthly. Precipitation data has smaller probability density than runoff data, therefore, rainfall patterns considering the previous and next days were proposed as 7 different types. Disaggregated rainfall was resampled from the only same rainfall patterns to improve applicability. The proposed method was applied rainfall data observed at Seoul weather station where has 52 years hourly rainfall data and the disaggregated hourly data were compared to the measured data. The proposed method might be applied to disaggregate the climate change scenarios.

• Journal of The Korean Society of Agricultural Engineers
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• v.62 no.4
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• pp.33-43
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• 2020

In order to reduce damage from farmland inundation caused by recent climate change, it is necessary to predict the risk of farmland inundation accurately. Inundation modeling should be performed by considering multiple time distributions of possible rainfalls, as digital forecasts of Korea Meteorological Administration is provided on a six-hour basis. As building multiple inputs and creating inundation models take a lot of time, it is necessary to shorten the forecast time by building a data base (DB) of farmland inundation probability. Therefore, the objective of this study is to establish a DB of farmland inundation probability in accordance with forecasted rainfalls. In this study, historical data of the digital forecasts was collected and used for time division. Inundation modeling was performed 100 times for each rainfall event. Time disaggregation of forecasted rainfall was performed by applying the Multiplicative Random Cascade (MRC) model, which uses consistency of fractal characteristics to six-hour rainfall data. To analyze the inundation of farmland, the river level was simulated using the Hydrologic Engineering Center - River Analysis System (HEC-RAS). The level of farmland was calculated by applying a simulation technique based on the water balance equation. The inundation probability was calculated by extracting the number of inundation occurrences out of the total number of simulations, and the results were stored in the DB of farmland inundation probability. The results of this study can be used to quickly predict the risk of farmland inundation, and to prepare measures to reduce damage from inundation.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.21 no.3
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• pp.183-191
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• 2021

Non-intrusive load monitoring is a technology that can be used for predicting and classifying the type of appliances through real-time monitoring of user power consumption, and it has recently got interested as a means of energy-saving. In this paper, we propose a system for classifying appliances from user consumption data by combining GAF(Gramian angular field) technique that can be used for converting one-dimensional data to the two-dimensional matrix with convolutional neural networks. We use REDD(residential energy disaggregation dataset) that is the public appliances power data and confirm the classification accuracy of the GASF(Gramian angular summation field) and GADF(Gramian angular difference field). Simulation results show that both models showed 94% accuracy on appliances with binary-state(on/off) and that GASF showed 93.5% accuracy that is 3% higher than GADF on appliances with multi-state. In later studies, we plan to increase the dataset and optimize the model to improve accuracy and speed.

• The Journal of Asian Finance, Economics and Business
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• v.7 no.12
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• pp.665-675
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• 2020

The aim of this article is to investigate the relationship between insurance and economic growth at aggregate and disaggregate level for the period 1982-2018. Very few studies have been carried out in this field, with contradictory results and using an aggregate data while, according to different authors, an aggregate data might provide spurious results. The author used Ordinary Least Squares Regressions (OLS) and Granger Causality tests to explore the strength and direction of the relationship between insurance and economic growth at an aggregate level. To check the relationship at disaggregate level life insurance, marine insurance, and property insurance are regressed on trade openness and investment, respectively. Non-life insurance at an aggregate level plays a positive and significant role in promoting economic growth, but life insurance has an insignificant impact on the Pakistan economy. On the other hand, non-life insurances at a disaggregated level such as marine insurance negatively affect a vital part of economic growth, i.e., trade. At the same time, property insurance has a significant and positive role in boosting investment. Life, marine, and property insurance Granger cause economic growth, trade, and investment in a single direction. Nevertheless, is a bi-directional relationship between economic growth and non-life insurance.

• Journal of Food Hygiene and Safety
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• v.10 no.2
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• pp.73-79
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• 1995

Incidents of seafood and massive fish kills have been rapidly increasing in both frequency and geographical distribution and the socioeconomic impacts brought by those incidents. However, the biological origins of those marine toxins have not been well clarified. Most of the marine organisms investigated are filter-feeder, which accumulate toxins from their food and/or their symbiotic microalgae. We have examined the action on rabbit platelets of marine toxins isolated from cultured dinoflagellates and sponge collected at Okinawa. Maitotoxin (MTX) is a water-soluble toxin isolated from the cultured dinoflagellate Gambierdiscus toxicus which causes a seafood poisoning in tropical regions. Zooxanthellatoxin A (ZT-A) was isolated from exteracts of cultured symbiotic dinoflagellate Symbiodinium sp. (socalled zooxanthella) from flatworms of the genus Amphiscolops collected at Okinawan marine sponge Theonella sp. MTX caused a disaggregation and a dissolution of large aggregates. ZT-A caused a dissolution of small aggregates followed by a increment of light tranmission. TZ-A caused an initial and transient shape change followed by a sustained aggregation and a increment of large aggregates. In conclusion, marine toxins exert unique patterns on the light trasmission and the size of aggregates in rabbit platelets by their concentrations and kinds

• Toxicological Research
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• v.14 no.3
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• pp.333-339
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• 1998

Sambutoxin, a newly purified mycotoxin in Koea, caused hemorrhage in the stomach and intestine of rats. To elucidate the mechanism of hemorrhage, effects of sambutoxin on rabbit platelet aggregation were investigated. First of all, the effects of sambutoxin on the platelet aggregation response and ATP release from platelet by various appregating factors were investigated. And then the role of $Ca^{2+}$ on the platelet aggregation was investigated by flow cytometer. Finally, morphological effect of sambutoxin on platelet ultrastructure was examined by transmission electron microscope. Sambutoxin inhibited aggregation induced by ADP, collagen, thrombin, and arachidonic acid and decreased platelet activating factor-induced disaggregation time in a dose dependent manner. Sambutoxin also decreased thrombin and arachidonic acid-induced ATP release, but increased all factors induced $Ca^{2+}$ release. Sambutoxin showed severe ultrastructural changes of platelet such as appearance of disorganization debri of cellular organelle in intercellular space. Our results indicate that sambutoxin inhibitis rabbit platelet aggregation, and it may be party due to the decrease of ATP release. However, it is not clear whether the antiaggregating effect of sambutoxin is related to $Ca^{2+}$ increase.

• Fashion & Textile Research Journal
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• v.11 no.4
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• pp.672-677
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• 2009

To reduce the dependence of wool dyeing on the temperature several solvents with different properties and structures were added to the dye bath of C. I. Acid Yellow 42. Nearly the same total solubility parameters(${\delta}_t$) of solvents as those of wool fiber and hydrophobic part of the dyestuff were needed to increase disaggregation of dye molecules, loosening the wool fiber and wickabilty of dyeing solution; besides, the large surface tension(${\gamma}$) value of the solvents and the well balanced values of the three-component Hansen solubility parameters such as dispersion(${\delta}_d$), polar(${\delta}_p$), and hydrogen(${\delta}_h$) bonding parameters were required. Among the added solvents dimethyl phthalate(DMP) and acetophenone(AP) were satisfied with these conditions and worked the most successfully in the low temperature wool dyeing. Their effectiveness proven by the dyeing rate and the activation energy ($E_a$) of the dyeing was in the order of DMP > AP > DBE > CH > M >NONE. In conclusion the total solubility parameters(${\delta}_t$), the three-component Hansen parameters and the surface tension(${\gamma}$) of DMP and AP could be the guidelines to select suitable solvents for low temperature wool dyeing.

• Journal of Mechanical Science and Technology
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• v.19 no.3
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• pp.887-893
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• 2005

The aggregability of red blood cells (RBCs) was determined by laser backscattering light analysis in a microfluidic channel. Available techniques for RBC aggregation often adopt a rotational Couette-flow using a bob-and-cup system for disaggregating RBCs, which causes the system to be complex and expensive. A disposable microfluidic channel and vibration generating mechanism were used in the proposed new detection system for RBC aggregation. Prior to measurement, RBC aggregates in a blood sample were completely disaggregated by the application of vibration-induced shear. With the present apparatus, the aggregation indexes of RBCs can be measured easily with small quantities of a blood sample. The measurements with the present aggregometer were compared with those of LORCA and the results showed a strong correlation between them. The aggregability of the defibrinogenated blood RBCs is markedly lower than that of the normal RBCs. The noble feature of this design is the vibration-induced disaggregation mechanism, which can incorporate the disposable element that holds the blood sample.

• Proceedings of the Korea Water Resources Association Conference
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• 2008.05a
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• pp.178-183
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• 2008

지구온난화로 인한 기후변화가 기정사실화 되면서 이러한 기후변화에 대비하기 위한 다양한 연구가 진행중이다. 수자원과 관련된 기후변화 연구를 살펴보면 초기에는 장기적 관점에서 기후변화가 유출에 미치는 영향에 대한 연구가 대부분을 이루고 있었으나 2003년을 기점으로 유럽을 중심으로 기후변화가 홍수량에 미치는 영향에 대한 연구가 시작되었다. 기후변화가 홍수에 미치는 영향을 평가하는데 가장 중요한 것은 수문시계열 자료의 해상도라고 할 수 있다. 이러한 시공간적 해상도 문제를 해결하기 위해서 세계 각국은 각국의 상황에 맞는 RCM을 개발하고 있으며 자국에 적합한 축소기법을 개발하고자 노력하고 있다. 따라서 본 연구에서는 고해상도 수문기상자료의 생성을 위하여 기후변화 모형으로부터 생성된 일 단위 강우자료를 시자료로 분해하기 위한 기법을 제시하고자한다. 지난 수십년 동안 강우나 기타 수문시계열 자료를 다양한 해상도의 자료로 변환하기 위한 연구가 진행되어왔다. 그러나 이러한 연구의 가장 큰 한계점은 대부분의 시계열 자료가 추계학적 특성을 가지고 있다고 가정한 후, 분석을 진행했다는 것이다. 이렇게 되면 강우발생에 따른 물리적 과정을 모형의 구조에 반영하는데 한계점을 드러내게 된다. 따라서 본 연구에서는 해상도를 변화시키는데 따른 강우의 운동역학적 특성을 고려하기 위하여 카오스를 기반으로 한 분해기법을 제시하고자 한다. 우선 카오스 분석을 통해서 지점 강우자료의 카오스 특성을 확인한 후, 현재까지 관측된 강우를 기반으로 $2CO_2$에서의 일 강우를 일 단위 보다 작은 단위로 분해하였다.