• Korean Journal of Agricultural Science
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• v.48 no.3
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• pp.515-526
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• 2021

The frequency of typhoons and torrential rainfalls has increased due to climate change, and the concurrent risk of breakage of dams and reservoirs has increased due to structural aging. To cope with the risk of dam breakage, a more accurate emergency action plan (EAP) must be established, and more advanced technology must be developed for the prediction of flooding. Hence, the present study proposes a method for establishing a more effective EAP by performing flood and inundation analyses using one- and two-dimensional models. The probable maximum flood (PMF) under the condition of probable maximum precipitation (PMP) was calculated for the target area, namely the Gyeong-cheon reservoir watershed. The breakage scenario of the Gyeong-cheon reservoir was then built up, and breakage simulations were conducted using the dam-break flood forecasting (DAMBRK) model. The results of the outflow analysis at the main locations were used as the basis for the one-dimensional (1D) and two-dimensional (2D) flood inundation analyses using the watershed modeling system (WMS) and the FLUvial Modeling ENgine (FLUMEN), respectively. The maximum inundation area between the Daehari-cheon confluence and the Naeseong-cheon location was compared for each model. The 1D flood inundation analysis gave an area of 21.3 km², and the 2D flood inundation analysis gave an area of 21.9 km². Although these results indicate an insignificant difference of 0.6 km² in the inundation area between the two models, it should be noted that one of the main locations (namely, the Yonggung-myeon Administrative and Welfare Center) was not inundated in the 1D (WMS) model but inundated in the 2D (FLUMEN) model.

• Proceedings of the Korea Water Resources Association Conference
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• 2015.05a
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• pp.14-14
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• 2015

공간보간기법은 미계측지역의 강수예측을 위해 통상적으로 사용되는 방법 중의 하나이다. 이 연구에서는 기상청에서 제공하고 있는 RCP 8.5 시나리오에 의한 남한상세 강수자료 중 지형이 복잡한 도서지역에서 제공되지 않는 데이터 누락격자에 대하여 최적의 공간보간기법을 선정하여 강수자료를 생성할 수 있도록 하였다. 적합한 보간기법을 선정하기 위해 데이터 누락지역에 대한 분석을 수행하였고, 최신 행정구역도에 맞추어 $1km{\times}1km$ 격자를 한반도 전체지역에 맞추어 생성된 격자를 사용하였다. ESRI사의 ArcGIS 프로그램을 이용하여 공간보간기법을 적용하였다. 사용된 보간법은 역거리가중치법(IDW), 정규크리깅(Ordinary Kriging), 보편크리깅(Universal Kriging), 스플라인(Spline)이며 가장 적합한 공간보간기법을 선정하기 위해 기후변화시나리오에 의한 데이터 중 해안선 주변 특정격자에서의 값을 누락시켜 공간보간기법을 통해 생성된 값과 기후변화 시나리오에 의한 값을 정량적으로 비교하였다. 공간보간기법의 적합도 평가를 위해 MAE(Mean Absolute Error), MSE(Mean Squared Error), PBIAS(Percent of BIAS), G(goodness of prediction) 분석을 수행하였고, 산점도 분석을 통해 실제값과 보간값의 오차율 평가를 병행하여 최적 공간보간기법을 결정하였다. 사용된 강수데이터는 RCP 8.5 시나리오에서 2015~2019년 중 강수가 높게 나타난 8월 자료를 이용하였다. 해안선 지역의 강수량 추정시 역거리 가중치법과 크리깅방법은 일부 지점에서 과다 추정되는 경향이 있고, 스플라인 방법이 전체적인 총 강수량이 기후변화시나리오에 의한 실제값과 유사한 것으로 나타났다. 실제값과 보간값의 교차검증을 수행한 결과 정규크리깅 기법이 가장 높은 정확도를 보였으며, 전체적으로 실제값과 유사한 범위내의 강수량이 생성되는 것으로 나타났다.

• Journal of Korean Society on Water Environment
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• v.27 no.3
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• pp.264-272
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• 2011

The objective of this study was to develop a model for predicting long-term runoff in a basin using the ensemble streamflow prediction (ESP) technique and review its reliability. To achieve the objective, this study improved not only the ESP technique based on the ensemble scenario analysis of historical rainfall data but also conventional ESP techniques used in conjunction with qualitative climate forecasting information, and analyzed and assessed their improvement effects. The model was applied to the Geum River basin. To undertake runoff forecasting, this study tried three cases (case 1: Climate Outlook + ESP, case 2: ESP probability through monthly measured discharge, case 3: Season ESP probability of case 2) according to techniques used to calculate ESP probabilities. As a result, the mean absolute error of runoff forecasts for case 1 proposed by this study was calculated as 295.8 MCM. This suggests that case 1 showed higher reliability in runoff forecasting than case 2 (324 MCM) and case 3 (473.1 MCM). In a discrepancy-ratio accuracy analysis, the Climate Outlook + ESP technique displayed 50.0%. This suggests that runoff forecasting using the Climate Outlook +ESP technique with the lowest absolute error was more reliable than other two cases.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.1
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• pp.313-320
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• 2021

This study develops a demand and supply model and price model for Miryang sesame leaf cultivation and predicts the optimal production level to maximize total profit for Miryang sesame leaf farms. We used time series data from 1996 to 2017, which are related to Miryang sesame leaf cultivation. For the analysis, we estimated the demand function and average cost function, calculated the optimal production level and price, and derived the optimal profit. In addition, we predicted the optimal production level, price, total revenue, total cost, and profit until the year 2030 through scenario analysis. The results show that the optimal production level until the year 2030 is between 10 and 12.5 thousand tons, while the production volume was 7 thousand tons in 2017, and total profit for Miryang sesame leaf farms is estimated at 13.3 to 21.3 billion Korean won in 2030. The producer group needs to maintain the optimal production level to maximize total profit for farmers, as suggested in this study.

• Journal of Biomedical Engineering Research
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• v.43 no.1
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• pp.27-34
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• 2022

Drunk driving defines a driver as unable to drive a vehicle safely due to drinking. To crack down on drunk driving, alcohol concentration evaluates through breathing and crack down on drinking using S-shaped courses. A method for assessing drunk driving without using BAC or BrAC is measurement via biosignal. Depending on the individual specificity of drinking, alcohol evaluation studies through various biosignals need to be conducted. In this study, we measure biosignals that are related to alcohol concentration, predict BrAC through SVM, and verify the effectiveness of the S-shaped course. Participants were 8 men who have a driving license. Subjects conducted a d2 test and a scenario evaluation of driving an S-shaped course when they attained BrAC's certain criteria. We utilized SVR to predict BrAC via biosignals. Statistical analysis used a one-way Anova test. Depending on the amount of drinking, there was a tendency to increase pupil size, HR, normLF, skin conductivity, body temperature, SE, and speed, while normHF tended to decrease. There was no apparent change in the respiratory rate and TN-E. The result of the D2 test tended to increase from 0.03% and decrease from 0.08%. Measured biosignals have enabled BrAC predictions using SVR models to obtain high Figs in primary and secondary cross-validations. In this study, we were able to predict BrAC through changes in biosignals and SVMs depending on alcohol concentration and verified the effectiveness of the S-shaped course drinking control method.

• Structural Engineering and Mechanics
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• v.78 no.3
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• pp.351-368
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• 2021

This paper, by applying a reliability-based framework, develops seismic vulnerability macrozonation maps for Tehran, the capital and one of the most earthquake-vulnerable city of Iran. Seismic performance assessment of 3-, 4- and 5-story steel moment resisting frames (SMRFs), designed according to ASCE/SEI 41-17 and Iranian Code of Practice for Seismic Resistant Design of Buildings (2800 Standard), is investigated in terms of overall maximum inter-story drift ratio (MIDR) and unit repair cost ratio which is hereafter known as "damage ratio". To this end, Tehran city is first meshed into a network of 66 points to numerically locate low- to mid-rise SMRFs. Active faults around Tehran are next modeled explicitly. Two different combination of faults, based on available seismological data, are then developed to explore the impact of choosing a proper seismic scenario. In addition, soil effect is exclusively addressed. After building analytical models, reliability methods in combination with structure-specific probabilistic models are applied to predict demand and damage ratio of structures in a cost-effective paradigm. Due to capability of proposed methodology incorporating both aleatory and epistemic uncertainties explicitly, this framework which is centered on the regional demand and damage ratio estimation via structure-specific characteristics can efficiently pave the way for decision makers to find the most vulnerable area in a regional scale. This technical basis can also be adapted to any other structures which the demand and/or damage ratio prediction models are developed.

• Journal of the Korean Institute of Gas
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• v.26 no.4
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• pp.36-40
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• 2022

Recently, the biggest topic in the industry is the area of industrial safety and health management. Since city gas is flammable gas and has a high risk of fire and explosion, much effort is required to prevent serious industrial and citizenry disasters. As part of city gas safety management, this study attempted to quantitatively predict the scope and degree of damage in the event of an explosion accident caused by city gas leakage through the Consequence Analysis. As a result, there was a difference in the accident result value according to various leakage conditions such as pressure and weather conditions. Through this study, a scenario of explosion due to city gas leakage will be prepared when performing city gas safety management work and used to prepare more effective accident prevention and emergency action plans.

• Journal of Advanced Technology Convergence
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• v.2 no.3
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• pp.59-66
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• 2023

The most important thing in digital transformation is SW technology. However, many companies are having difficulty securing SW technology and manpower. In particular, it is reported that the shortage of SW manpower will increase further. The government is carrying out manpower training policies and many support projects to resolve SW manpower supply and demand policies, but accurate predictions of demand and supply of the software industry are essential for these policies to be effectively established. Therefore, this study developed a simulation using a system dynamics methodology that can perform dynamic structural analysis to resolve the supply and demand imbalance in the software industry. System dynamics is appropriate to find the cause and policy alternatives from a dynamic perspective on the imbalance in manpower supply and demand in the software industry. In detail, the U.S. Bureau of Labor Statistics (BLS) methodology was used to develop a prediction model for manpower demand and supply in the software industry, and scenario analysis was performed to derive policy implications.

• Journal of the Korea Society of Computer and Information
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• v.28 no.10
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• pp.267-275
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• 2023

The digital transformation of the shipbuilding, shipping, and logistics sectors is predicted to lead to the introduction of autonomous ships and changes in the way ships are operated. The co-existence of various operation forms, such as autonomous operation and remote operation, with the existing operation methods is expected to lead to the transformation of the ship operation process and the emergence of new stakeholders. This paper studies the future ship operation process according to the change in ship operation method, predicts the change in the operating environment of future ships, and derives functional requirements by major tasks and stakeholders. The Delphi technique is applied to construct a ship operation scenario from the planning stage of voyage and cargo transport to the stage of arrival at the final destination port and discharge of cargo, and to predict future work changes by task and actor. Seafarers' activities are expected to be minimised by remote and autonomous operation, and experts in each field are expected to have responsibilities and tasks in different aspects of ship operation.

• Steel and Composite Structures
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• v.49 no.5
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• pp.533-546
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• 2023

Cost-effective solutions provided by composite construction are gaining popularity which, in turn, promotes the appearance on the market of new types of composite sections that allow not only to take advantage of the synergy of steel and concrete working together at room temperature, but also to improve their behaviour at high temperatures. When combined with high performance materials, significant load-bearing capacities can be achieved even with reduced cross-sectional dimensions. Steel-reinforced concrete-filled steel tubular (SR-CFST) columns are one of these innovative composite sections, where an open steel profile is embedded into a CFST section. Besides the renowned benefits of these typologies at room temperature, the fire protection offered by the surrounding concrete to the inner steel profile, gives them an enhanced fire performance which delays its loss of mechanical capacity in a fire scenario. The experimental evidence on the fire behaviour of SR-CFST columns is still scarce, particularly when combined with high performance materials. However, it is being much needed for the development of specific design provisions that consider the use of the inner steel profile in CFST columns. In this work, a new experimental program on the thermo-mechanical behaviour of SR-CFST columns is presented to extend the available experimental database. Ten SR-CFST stub columns, with circular and square geometries, combining high strength steel and concrete were tested. It was seen that the circular specimens reached higher failure times than the square columns, with the failure time increasing both when high strength steel was used at the embedded steel profile and high strength concrete was used as infill. Finally, different proposals for the reduction coefficients of high performance materials were assessed in the prediction of the cross-sectional fire resistance of the SR-CFST columns.