• Title/Summary/Keyword: Operational Environment

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A Concept and Operational Assumptions of OS Security Enhancement System (운영체제보안시스템의 개념 및 운영 가정사항)

  • Tai-hoon Kim;Sang-ho Kim;Jae-sung Kim
    • Proceedings of the Korea Society for Simulation Conference
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    • 2003.11a
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    • pp.119-125
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    • 2003
  • Trusted operating systems (OS) provide the basic security mechanisms and services that allow a computer system to protect, distinguish, and separate classified data. This paper proposes a new concept of operating system security enhancement system which uses loadabel security kernel module (LSKM) or dynamic link library(DLL) and specific conditions for operational environment should be assumed.

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Operational Water Temperature Forecast for the Nakdong River Basin Using HSPF Watershed Model (HSPF 유역모델을 이용한 낙동강유역 실시간 수온 예측)

  • Shin, Chang Min;Na, Eun Hye;Kim, Duck Gil;Kim, Kyunghyun
    • Journal of Korean Society on Water Environment
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    • v.30 no.6
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    • pp.673-682
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    • 2014
  • A watershed model was constructed using Hydrological Simulation Program Fortran to predict the water temperature at major tributaries of Nakdong River basin, Korea. Water temperature is one of the most fundamental indices used to determine the nature of an aquatic environment. Most processes of an aquatic environment such as saturation level of dissolved oxygen, the decay rate of organic matter, the growth rate of phytoplankton and zooplankton are affected by temperature. The heat flux to major reservoirs and tributaries was analyzed to simulate water temperature accurately using HSPF model. The annual mean heat flux of solar radiation was estimated to $150{\sim}165W/m^2$, longwave radiation to $-48{\sim}-113W/m^2$, evaporative heat loss to $-39{\sim}-115W/m^2$, sensible heat flux to $-13{\sim}-22W/m^2$, precipitation heat flux to $2{\sim}4W/m^2$, bed heat flux to $-24{\sim}22W/m^2$ respectively. The model was calibrated at major reservoir and tributaries for a three-year period (2008 to 2010). The deviation values (Dv) of water temperature ranged from -6.0 to 3.7%, Nash-Sutcliffe efficiency(NSE) of 0.88 to 0.95, root mean square error(RMSE) of $1.7{\sim}2.8^{\circ}C$. The operational water temperature forecasting results presented in this study were in good agreement with measured data and had a similar accuracy with model calibration results.

A Study on the Operational Forecasting of the Nakdong River Flow with a Combined Watershed and Waterbody Model (실시간 낙동강 흐름 예측을 위한 유역 및 수체모델 결합 적용 연구)

  • Na, Eun Hye;Shin, Chang Min;Park, Lan Joo;Kim, Duck Gil;Kim, Kyunghyun
    • Journal of Korean Society on Water Environment
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    • v.30 no.1
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    • pp.16-24
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    • 2014
  • A combined watershed and receiving waterbody model was developed for operational water flow forecasting of the Nakdong river. The Hydrological Simulation Program Fortran (HSPF) was used for simulating the flow rates at major tributaries. To simulate the flow dynamics in the main stream, a three-dimensional hydrodynamic model, EFDC was used with the inputs derived from the HSPF simulation. The combined models were calibrated and verified using the data measured under different hydrometeological and hydraulic conditions. The model results were generally in good agreement with the field measurements in both calibration and verification. The 7-days forecasting performance of water flows in the Nakdong river was satisfying compared with model calibration results. The forecasting results suggested that the water flow forecasting errors were primarily attributed to the uncertainties of the models, numerical weather prediction, and water release at the hydraulic structures such as upstream dams and weirs. From the results, it is concluded that the combined watershed-waterbody model could successfully simulate the water flows in the Nakdong river. Also, it is suggested that integrating real-time data and information of dam/weir operation plans into model simulation would be essential to improve forecasting reliability.

A study on the mitigation model development for minimizing the incidents of disk unit in information system's operational risks (디스크 장애예방을 위한 피해저감모델 개발에 관한 연구 - 정보시스템 운영리스크의 관점에서 -)

  • Hwang, Myung-Soo;Lee, Young-Jai
    • The KIPS Transactions:PartD
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    • v.14D no.6
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    • pp.689-700
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    • 2007
  • Organizations and customers lose if business activities we discontinued by an incident of information systems under the current business environment because they pursue real time enterprise and on demand enterprise. The loss includes the intangible decline in brand image, customer separation, and the tangible loss such as decrease in business profits. Thus. it is necessary to have preparedness in advance and mitigation for minimization of a loss due to the business discontinuity and information system's operational risks. This paper suggests the mitigation model for minimizing the incidents of disk unit in information system's operational risks. The model will be represented by a network model which is composed of the three items as following: (1) causes, attributes, indicators of an operational risk, (2) a periodic time through an analysis of historical data, (3) an index or a regulation related to the examination of causes of an operational risk.

Operational Water Quality Forecast for the Nakdong River Basin Using HSPF Watershed Model (HSPF 유역모델을 이용한 낙동강유역 수질 예측)

  • Shin, Chang Min;Kim, Kyunghyun
    • Journal of Korean Society on Water Environment
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    • v.32 no.6
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    • pp.570-581
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    • 2016
  • A watershed model was constructed using the Hydrological Simulation Program Fortran to predict the water quality, especially chlorophyll-a concentraion, at major tributaries of the Nakdong River basin, Korea. The BOD export loads for each land use in HSPF model were estimated at $1.47{\sim}8.64kg/km^2/day$; these values were similar to the domestic monitoring export loads. The T-N and T-P export loads were estimated at $0.618{\sim}3.942kg/km^2/day$ and $0.047{\sim}0.246kg/km^2/day$, slightly less than the domestic monitoring data but within the range of foreign literature values. The model was calibrated at major tributaries for a three-year period (2008 to 2010). The deviation values ranged from -31.5~1.6% of chlorophyll-a, -24.0~2.2% of T-N, and -5.7~34.8% of T-P. The root mean square error (RMSE) ranged from 4.3~44.4 ug/L for chlorophyll-a, -0.6~1.5 mg/L for T-N, and 0.04~0.18 mg/L for T-P, which indicates good calibration results. The operational water quality forecasting results for chlorophyll-a presented in this study were in good agreement with measured data and had an accuracy similar with model calibration results.

Development of the Korea Ocean Prediction System

  • Suk, Moon-Sik;Chang, Kyung-Il;Nam, Soo-Yong;Park, Sung-Hyea
    • Ocean and Polar Research
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    • v.23 no.2
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    • pp.181-188
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    • 2001
  • We describe here the Korea ocean prediction system that closely resembles operational numerical weather prediction systems. This prediction system will be served for real-time forecasts. The core of the system is a three-dimensional primitive equation numerical circulation model, based on ${\sigma}$-coordinate. Remotely sensed multi-channel sea surface temperature (MCSST) is imposed at the surface. Residual subsurface temperature is assimilated through the relationship between vertical temperature structure function and residual of sea surface height (RSSH) using an optimal interpolation scheme. A unified grid system, named as [K-E-Y], that covers the entire seas around Korea is used. We present and compare hindcasting results during 1990-1999 from a model forced by MCSST without incorporating RSSH data assimilation and the one with both MCSST and RSSH assimilated. The data assimilation is applied only in the East Sea, hence the comparison focuses principally on the mesoscale features prevalent in the East Sea. It is shown that the model with the data assimilation exhibits considerable skill in simulating both the permanent and transient mesoscale features in the East Sea.

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Development of Verification Environment for Flight Safety Critical Software using NEXUS (NEXUS를 이용한 비행안전 필수 소프트웨어 검증환경 개발)

  • Yoon, Hyung-Sik;Han, Jong-Pyo
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.40 no.6
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    • pp.548-554
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    • 2012
  • Verification and validation of operational software of the flight control computer, which is flight safety critical, is very important to prove correctness and faultness of the software. To verify the real-time softare requirement on operational software of flight control computer, real-time software internal parameter and variable monitoring technics on hardware-in-the-loop environment, similar to on-flight environment, is required. This paper describes flight safety critical software validation and verificiation environment using standard debugging interface, NEXUS 5001.

Optimization of Operational Conditions of Existing BNR Process with Various C/N Ratio using Simulation Method (시뮬레이션 기법을 이용한 기존 BNR공정의 C/N비 변화에 따른 운전조건 최적화)

  • Rho, Hae-Yeon;Gil, Kyung-Ik
    • Journal of Korean Society on Water Environment
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    • v.23 no.3
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    • pp.367-370
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    • 2007
  • Numerous sets of simulation were conducted in order to find out the optimum operational conditions of the existing BNR process using GPS-X program. The model of ASM3 and modified Bio-P module were applied for simulations. From the result of this study, effluent quality was closely related with the step feeding rate and influent C/N ratio. The effluent TN concentration seemed to be significantly affected by step feeding rate at the low C/N condition. But at the high C/N condition, the effluent concentration of TP rather than that of TN was affected by the control of step feeding rate.

Operational Condition and Temperature Study for Ethylbenzene Treating Biofilter

  • Son, Hun-Keun;Bradley A. Striebig
    • Journal of Environmental Health Sciences
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    • v.29 no.4
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    • pp.4-9
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    • 2003
  • Biofiltration can effectively remove both organic and inorganic air pollution compounds from both industrial and public sources. However, for the optimal biofiltration performance, it is necessary to gain a better understanding of the inner environment and destruction mechanisms within a biofilter. The effects of operational factors on removal efficiency was studied. Generally, removal efficiency decreases as the loading rate increases. Temperature, as one of the key factors that affect biofiltration design and performance, was also investigated. Conceptually, the biofilter reactor of this paper was divided into five different consecutive stages. The more ethylbenzene COD degraded at each stage, the higher the temperature increases observed compared to the temperatures of the previous stages. It was observed that for every 1 kg of ethylbenzene COD degraded per cubic meter of biofilter media, there was generally a 0.41$^{\circ}C$ increase in the temperature of that stage.

Photocatalytic Degradation of Atrazine and PCP using TiO2 (TiO2 광촉매를 이용한 Atrazine과 PCP의 분해)

  • Park, Jae-Hong;An, Sang-Woo;Chang, Soon-Woong
    • Journal of Korean Society on Water Environment
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    • v.20 no.6
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    • pp.577-582
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    • 2004
  • The photocatalytic degradation of atrazine and PCP, a endocrine disruptors, has been investigated over $TiO_2$ photocatalysts under ultraviolet (UV) light irradiation. The effect of operational parameters, i.e., pH, light intensity and persulphate concentration on the degradation rate of aqueous solution of atrazine and PCP has been examined. The results presented in this work demonstrate that, as pH and the light intensity increased, the photocatalytic reaction rates were enhanced. Individual use of $TiO_2$-persulphate was far more effective than using only $TiO_2$ in atrazine and PCP removal. Based on the overall experimental results, the photocatalytic oxidation of atrazine and PCP with the coated $TiO_2$ photocatalyst is found to be very effective under the operational conditions delineated in this study.