• Atmosphere
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• v.31 no.4
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• pp.445-459
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• 2021

This study uses a cloud-resolving storm simulator (CReSS) to understand the individual effect of determinant meteorological factors on snowfall characteristics in the Yeongdong region based on the rawinsonde soundings for two snowfall cases that occurred on 23 February (Episode 1) and 13 December (Episode 2) 2016; one has a single-layered cloud and the other has two-layered cloud structure. The observed cloud and precipitation (snow crystal) features were well represented by a CReSS model. The first ideal experiment with a decrease in low-level temperature for Episode 1 indicates that total precipitation amount was decreased by 19% (26~27% in graupel and 53~67% in snow) compared with the control experiment. In the ideal experiment that the upper-level wind direction was changed from westerly to easterly, although total precipitation was decreased for Episode 1, precipitation was intensified over the southwestern side (specifically in terrain experiment) of the sounding point (128.855°E, 37.805°N). In contrast, the precipitation for Episode 2 was increased by 2.3 times greater than the control experiment under terrain condition. The experimental results imply that the low-level temperature and upper-level dynamics could change the location and characteristics of precipitation in the Yeongdong region. However, the difference in precipitation between the single-layered experiment and control (two-layered) experiment for Episode 2 was negligible to attribute it to the effect of upper-level cloud. The current results could be used for the development of guidance of snowfall forecast in this region.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.2
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• pp.158-164
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• 2018

Wind power forecast is critical for efficient power system operation. However, wind power has high forecasting errors due to uncertainty caused by the climate change. These forecasting errors can have an adverse impact on the power system operation. In order to mitigate the issues caused by the wind power forecasting error, wind power curtailment and energy storage system (ESS) can be introduced in the power system. These methods can affect the economics of wind power resources. Therefore, it is necessary to evaluate the economics of the methods for mitigating the wind power forecasting error. This paper attempts to analyze the economics of wind power curtailment and ESS operation for mitigating wind power forecasting error. Numerical simulation results are presented to show the economic impact of wind power curtailment and ESS operation.

• Journal of Environmental Science International
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• v.21 no.4
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• pp.461-470
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• 2012

Agriculture is more influenced by environmental factors rather than other industries. Among the environmental factors, the meteorological conditions mainly impact the output of agricultural products. Hence, the purpose of this study is to analyze the impact of meteorological factors on the output of elemental agricultural products. As a first step, we obtained the data of the meteorological factors (i.e., precipitation, humidity, temperature, insolation, snowdrifts, wind velocity) and the output of the various agricultural products (i.e., grain, fruits and vegetables, root crops, green vegetables, seasoned vegetables, fruits, special crops) from the year 1990 to 2009 (20 years) of Seoul and the six metropolitan cities in Korea. Then, the analysis of the correlation between the agricultural product with the largest output and the meteorological factors of the place where the corresponding agricultural product is most produced, was carried out in order to determine the core meteorological factor that most impacts the output of agricultural product. The correlation analysis revealed that humidity, insolation and wind velocity have been the crucial meteorological factors to influence the output of the agricultural products. From the result, we can induce that the meteorological forecast information about the vital meteorological factors, i.e., humidity, insolation and wind velocity, facilitates the optimized cultivation plan to maximize the output of agricultural products.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.2 no.2
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• pp.1-10
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• 1982

Presently, most of rail stations are situated on the surface of dowl1town and thus result in heavy traffic congestion and inefficient use of land. This paper analyzes the impact of alternative locations of station On urban traffic patterns by simulating transportation systems, of Busan city. Since location of station has long-term effects on land use and transportation, 20 years forecast of land use change, trip generation, trip distribution, modal split and network assignment was performed for each alternative, and aggregate Impacts On passenger-km and passenger-hour were computed. The result indicated that Bujeon is the most desirable location of station in terms of traffic movement, compared to the alternative locations of Sasang and existing station. Relocation of rail station, however, should be decided with broader analysis including other aspects, such as urban development, environment, construction and operating costs, etc.

• The Journal of Asian Finance, Economics and Business
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• v.7 no.9
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• pp.219-228
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• 2020

The study investigates the impact of inflation rate on economic growth to find the best-fit model for economic growth in Vietnam. The study applied Vector Autoregressive (VAR), cointegration models, and unit root test for the time-series data from 1996 to 2018 to test the inflation impact on the economic growth in the short and long term. The study showed that the two variables are stationary at lag first difference I(1) with 1%, 5% and 10%; trace test indicates two cointegrating equations at the 0.05 level, the INF does not granger cause GDP, the optimal lag I(1) and the variables are closely related as R2 is 72%. It finds that the VAR model's results are the basis to perform economic growth; besides, the inflation rate is positively related to economic growth. The results support the monetary policy. This study identifies issues for Government to consider: have a comprehensive solution among macroeconomic policies, monetary policy, fiscal policy and other policies to control and maintain the inflation and stimulate growth; set a priority goal for sustainable economic growth; not pursue economic growth by maintaining the inflation rate in the long term, but take appropriate measures to stabilize the inflation at the best-fitted VAR forecast model.

• The Journal of the Acoustical Society of Korea
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• v.28 no.1E
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• pp.23-28
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• 2009

At the crossings of turnout systems, noise is generated by the impact of train on the connection points. However, rapid movement changes between rail and wheels on connection point are inevitable on existing turnout section which may cause safety concern as well as noise problem caused by repeated impact load by passing train. And given the turnout is a complicated system which combines various functions such as rolling stock, trackbed, signaling, communication and electrical system, it's very difficult to expect to improve the overall performance of the turnout in such a way of optimizing only particular part of such integrated system. Since the turnout is the only movable section among the integrated parts and has complicated structure that inevitably brings about quick and sudden movement, safety has been still put on the top of the list. This study was aimed at comparing and analyzing the noise data obtained around the turnout of existing railway, by categorizing them into tilting train, high speed train and traditional train, and by distance, speed and type of turnout. And based on the data measured, the forecast of noise level when tilting train accelerates around a turnout was conducted in the study.

• Journal of Environmental Impact Assessment
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• v.20 no.5
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• pp.765-777
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• 2011

According to the total pollution load management system, exact prediction and analysis of water quality and discharge has been required in order to allocate the amount of pollution load to each local government. In this study, QUAL2E model was used for comparison with other water quality models and improve the inadequate to forecast future water quality. And Various calibration and verification methods were applied to deal with existing uncertainties of parameter during modeling water quality. For user convenience, A GUI(Graphical User Interface) system named "QL2-XP" model is developed by object-oriented language for the user convenience and practical usage. Suggested GUI system consist of hydraulic analysis, water quality analysis, optimized model calibration processes, and postprocessing the simulation results. Therefore this model will be effectively utilized to manage practical and efficient water quality.

• Korean System Dynamics Review
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• v.13 no.2
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• pp.25-45
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• 2012

The purpose of this study is to estimate the effects of healthy city policies on residents' walking. In order to estimate promotion of walking rates by healthy cities policies, it developed System dynamics(SD)-based model which showed causal relationships among urban design, public health policies, and walking levels. SD technique is useful for future forecast and policy impact assessment. The spatial units of the SD-based system for policy impact assessment included 66 cities, counties, and communities in Seoul Metropolitan Area. The system simulation was planned to be run for 21 years from 2009 to 2030. For this study, 3 alternatives were proposed with combinations of length of bike lanes, number of bus routes, crime rates, self-reported good health status rates, and obesity rates. As a result of simulations, residents' participation rates for walking were increased from 1.00% to 9.98%. This study contributes to better understanding the benefits of healthy cities that are associated with individual walking. It further provided useful insights into planners' role in promoting health. The paper concluded with a discussion on future research opportunities and implications for public policies in urban and transportation and public health.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.43 no.4
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• pp.59-66
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• 2020

In this study, we consider the problem of forecasting the number of inbound foreigners visiting Korea. Forecasting tourism demand is an essential decision to plan related facilities and staffs, thus many studies have been carried out, mainly focusing on the number of inbound or outbound tourists. In order to forecast tourism demand, we use a seasonal ARIMA (SARIMA) model, as well as a SARIMAX model which additionally comprises an exogenous variable affecting the dependent variable, i.e., tourism demand. For constructing the forecasting model, we use a search procedure that can be used to determine the values of the orders of the SARIMA and SARIMAX. For the exogenous variable, we introduce factors that could cause the tourism demand reduction, such as the 9/11 attack, the SARS and MERS epidemic, and the deployment of THAAD. In this study, we propose a procedure, called Measuring Impact on Demand (MID), where the impact of each factor on tourism demand is measured and the value of the exogenous variable corresponding to the factor is determined based on the measurement. To show the performance of the proposed forecasting method, an empirical analysis was conducted where the monthly number of foreign visitors in 2019 were forecasted. It was shown that the proposed method can find more accurate forecasts than other benchmarks in terms of the mean absolute percentage error (MAPE).

• International conference on construction engineering and project management
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• 2005.10a
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• pp.1231-1236
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• 2005

Global construction projects manifest more risks than do other industries. Often, firms doing business in construction markets find these risks intimidating. To secure corresponding profits, many global contractors attempt to forecast the effects of risks and establish risk management strategies. However, one key problem with present-day risk management methods is that they are basically analytical or mathematical-oriented approaches which are not easy to adopt in real business. Based on preliminary investigations and evaluations of current tools, this research elicits more practical algorithms for risk checklist by constructing risk scenarios over the whole period of project execution. For the application of the algorithms, a "SE/RF" (Source-Event/Regular-Floating) checklist is suggested, which sorts out risk sources and their subsequent events, as well as dividing various risk factors into either regular or floating categories. In addition, the "PIS" (Probability-Impact-Significance) method is introduced, in place of traditional "PI" (Probability-Impact) methods, by adding the additional criterion of "risk significance" to determine the degree of risk exposure in a more realistic way. As a result, we draw the significant finding that the "PIS" method presents a closer evaluation regarding degree of risk exposure as compared to the level of expert judgments than those from traditional methods. Finally, we provide an integrated procedure for international project risk management with all of the research achievements being incorporated.