• Environmental Analysis Health and Toxicology
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• v.14 no.1_2
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• pp.65-73
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• 1999

Dioxins refer to a family of chemicals comprising 75 polychlorinated dibenzo-p-dioxin (PCDD) and 135 polychlorinated dibenzo-p-furan (PCDF) congeners, which may cause skin disorder, human immune system disruption, birth defects, severe hormonal imbalance, and cancer. The effects of exposure of dioxin-like compounds such as PCBs are mediated by binding to the aryl hydrocarbon receptor (AHR), which is a ligand-activated transcription factor. To grasp physicochemical factors affecting human toxicity of dioxins, six geometrical and topological indices, eleven thermodynamic variables, and quantum mechanical descriptors including ESP (electrostatic potential) were analyzed using QSAR and semi-empirical AM1 method. Planar dioxins with high lipophilicity and large surface tension show the probability that negative electrostatic potential in the lateral oxygen may make hydrogen bonding with DNA bases to be a carcinogen.

• Proceedings of the KSME Conference
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• 2004.04a
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• pp.733-738
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• 2004

This paper deals with feedback control of a hydraulic unit for direct yaw moment control, a method used to actively maintain the dynamic stability of an automobile. The uncertain parameters and complex structure naturally call for empirical modeling of the hydraulic unit, which readily results in a control-oriented model with high fidelity. The identified model is cross-validated against experimental data under various conditions, which helps to establish model uncertainty. Then, the $H_{\infty}$ optimization technique is employed to synthesize a controller with guaranteed robust stability and performance against the model uncertainty. The performance of the synthesized controller is verified using experimental results, which shows the viability of the proposed approach in a real-world application.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.04a
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• pp.133-138
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• 2000

MgO thin films were deposited using $Mg(tmhd)_2$ as a precursor dissolved in a solvent by electrostatic spray pyrolysis. When a pure tetra hydro furan was used as a solvent, a large number of particles appeared on the MgO thin film surface due to homogeneous nucleation. However, by adding 1-butyl alcohol or 1-octyl alcohol to THF, homogeneous nucleation was restricted and the number density of the large particles was also drastically reduced. X-ray diffraction analysis showed that the MgO films had a (100) preferred orientation regardless of the type of solvents used. Characterization using Fourier Transformed-Infrared and spectroscopic photometer revealed that the crystallized MgO thin films on the glass substrate had a high optical transmittance (> 85 %) in the visible range. Discharge characteristics of MgO thin films deposited by ESP method on an alternating-current plasma display panel were compared with a MgO thin film prepared by reactive radio-frequency planar magnetron sputtering.

• Proceedings of the SAREK Conference
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• 2006.06a
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• pp.311-318
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• 2006

CFD simulation is a tool very useful to predict the generation and absorption of the contaminant from the construction materials for the single room condition. However, there is a limit in multi-room simulation for analyzing air movement and contaminant concentration at the condition that the door of each room was closed. A lot of network simulation tool were developed which can used to analyze the mass transfer and contaminant concentration as results in the multi-room condition. However, existing network simulation method was not able to analyze the change of the heating and cooling load with the ventilation as though the change of the indoor air-pollution density was predictable. In this study, new approach to predict heating/cooling load and indoor contaminant concentration will be reviewed. New indoor contaminant concentration module reviewed in this study wad coupled with existing ESP-r network simulation method. The validity of new approach will be analysed for comparison the results of simulation and field measurement results.

• Convergence Security Journal
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• v.3 no.1
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• pp.73-84
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• 2003

The IPv4 that used to be generally used as a medium of computer communications in 1980s has reached its limits now. IPv6 (IP Version 6) is being prepared to solve the limitations of the IPv4. However, the biggest problem of IPv6 is that it is not compatible with the IPv4. To resolve the compatibility issue, Dual Stack, Tunneling and Header Converting methods have been proposed. The Header Converting method allows communications between the IPv4 and IPv6 networks with the converter. This method's strength is that it is easy to embody and the procedures for embodiment is simple. However, this method still contains the weaknesses that the existing IPv4 has. On the current document, the Header Converting method among the three methods is discussed to resolve the problems this method has. To solve the Header Converting method's weakness, the security problem between sections, the IP Header field values are converted to the relative field values and IPSec (IP Security) and ESP (Encapsulation Security Payload) are applied. The proposed "Encrypted Header Converting Method" that is encrypted in packet units has solved the weakness that the pre-existing Header Converting method used to have.d to have.

• Journal of the Korean Society of Food Science and Nutrition
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• v.39 no.12
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• pp.1893-1897
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• 2010

The total polyphenol contents and antioxidative activities of water and ethanol extracts from Synurus excelsus and Synurus palmatopinnatifidus var. palmatopinnatifidus were determined. Total polyphenol contents of ESE and ESP were 195.7 and 216.2 mg/g, and were higher than WSE (74.7 mg/g) and WSP (77.4 mg/g). The total flavonoid contents were also higher in ESE (176.6 mg/g) and ESP (148.8 mg/g) than WSE and WSP. DPPH radical scavenging activities of ESE and ESP (73.1 and 73.4%) were higher than WSE and WSP as like total polyphenol and flavonoid contents. Although the DPPH radical scavenging activities of the extracts were proportional to total polyphenol contents, there are no differences between water extracts and ethanol extracts of Synurus excelsus and Synurus palmatopinnatifidus on ABTS radical scavenging activities. Moreover, all the solvent extracts (ESE, ESP, WSE and WSP) had no SOD-like activity. These results suggest that consideration for adoption of method is necessary to evaluate antioxidative activity of extracts from plants including vegetables.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.9
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• pp.3869-3875
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• 2012

In this study, mathematical modeling and experimental analysis were executed in order to evaluate the valve dynamic characteristics when the hydraulic pressure applied. High pressure on the master cylinder effects on the valve dynamic characteristics have been analyzed. The pulsation pressure generated in hydraulic systems causes noise, vibration and odd effect to the system. To reduce the pulsation pressure, high frequency PWM control of 20KHz was attempted. Also, an analytic method is proposed for the resultant forces of electromagnetism and hydraulic pressure generated in the real vehicle electro stability program. Consequently, results of solenoid valve dynamic characteristics analysis derived in the study can be confirmed criteria for the optimal control of electronic stability program system.

• Journal of Korean Society on Water Environment
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• v.28 no.3
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• pp.359-366
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• 2012

Accurate predictions about the water quality of a river have great importance in identifying in-stream flow and water supply requirements and solving relevant environmental problems. In this study, the effect of water release from upstream dam on the downstream water quality has been investigated by applying a hydological model combined with QUAL2E to Geum River basin. The ESP (Ensemble Stream Prediction) method, which has been validated and verified by lots of researchers, was used to predict reservoir and tributary inflow. The input parameters for a combined model to predict both hydrological characteristics and water quality were identified and optimized. In order to verify the model performance, the simulated result at Gongju station, located at the downstream from Daecheong Dam, has been compared with measured data in 2008. As a result, it was found that the proposed model simulates well the values of BOD, T-N, and T-P with an acceptable reliability.

• Journal of Pharmaceutical Investigation
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• v.5 no.1
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• pp.41-48
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• 1975

Extrusion-Spheronization Processing (ESP) was applied to preparate sustained release spherical particles as a form of matrix spherical particle (MSP). dl-methylephedrine HCI (ME) was the drug chosen and several dissolution retardants and binders were selected to estimate a relatively good formulation on this purpose. The effect of physicochemical nature, concentration, and solvents of these dissolution retardants and binders on regularity in shape of MSP and in vitro release rate was investigated. The effect of Particle size of matrix particles was also evaluated. It is, therefore, concluded that this ESP would be a relatively good preparation method of sustained release MSP of ME which has the sustained action of about 5 and 8 hours by formulating of ethylcellulose and ethylcellulose-paraffin as a dissolution retardant, respectively, and then ethylcellulose solution of 80% EtOH is recommended as a binder.

• Proceedings of the Korea Water Resources Association Conference
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• 2020.06a
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• pp.153-153
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• 2020

우리나라에선 크고 작은 가뭄 피해가 자주 일어나고 있으며 최근엔 유래 없는 다년가뭄이 발생하면서 가뭄에 대한 경각심이 커지고 있다. 가뭄에 적절하게 대응하여 피해를 경감시키기 위해서는 신뢰도 높은 가뭄 예측이 선행되어야 한다. 이에 본 연구는 앙상블 예측과 베이즈이론(Bayes' theorem)을 수문학적 가뭄지수 중 하나인 SRI(Standardized Runoff Index)에 적용해 가뭄 확률 전망을 실시했으며 이를 EDP(Ensemble Drought Prediction)라고 칭하였다. 국내 8개 댐유역에서 EDP를 생성하고 개선하는 과정은 다음과 같이 진행된다. 우선 TANK모형을 활용한 1개월 선행 유량 예측(Ensemble Streamflow Prediction, ESP)의 결과를 SRI로 변환하여 EDP 확률분포를 생성한다. 그런 다음, EDP를 개선하기 위해 그 기초인 ESP에서 미흡한 토양수분 초기조건을 보완하고자 베이즈이론을 활용했다. APCC(APEC Climate Center)의 위성 관측 SMI(Soil Moisture Index) 자료로 SRI와의 회귀식을 구축, 이를 우도함수로 정의해 사전 EDP 분포를 업데이트한 EDP+ 확률분포를 생성했다. 그 결과, EDP와 EDP+ 모두 심도가 깊은 가뭄을 전망할수록 예측력이 기후학적 예측보다 좋지 않았다. 그럼에도 우도함수로 사용한 회귀식의 정확도가 높을수록 EDP+의 정확도도 향상되는 경향이 나타났으며, 이는 베이즈이론을 사용한다면 가뭄 확률 전망을 개선할 수 있다는 것을 의미하고 있다. 하지만, 확정 전망 정확도는 확률 전망 정확도와는 관계가 없었는데 이는 확정 전망과 확률 전망이 본질적으로 다르기 때문인 것으로 사료된다.