• 대기
• /
• 제31권2호
• /
• pp.157-170
• /
• 2021

To investigate the effect of snowfall on the traffic of general roads in Gangwon-do, case analysis was performed in Gangneung, Pyeongchang, and Chuncheon using ASOS (Automated Synoptic Observing System) snowfall data and VDS (Vehicle Detector System) traffic data. First, we analyzed how much the traffic volume and speed decrease in snowfall cases on regional roads compared to non-snow cases, and the characteristics of monthly reduction due to snowfall were investigated. In addition, Pearson correlation analysis and regression analysis were performed to quantitatively grasp the effect of snowfall on traffic volume and speed, and sensitivity tests for snowfall intensity and cumulative snowfall were performed. The results showed that the amount of snowfall caused decrease both in the traffic volume and speed from usual (non-snowfall) condition. However, the trend was different by region: The decrease rate in traffic volume was in the order of Gangneung (17~22%), Chuncheon (14~17%), and Pyeongchang (11~14%). The decrease rate in traffic speed was in the order of Chuncheon (9~10%), Gangneung (8~9%), Pyeongchang (5~6%). No significant results were found in the monthly decrease rate analysis. In all regions, traffic volume and speed showed a negative correlation with snowfall. It was confirmed that the greater the amount of traffic entering the road, the greater the slope of the trend line indicating the change in snowfall due to the traffic volume. As a result of the sensitivity test for snowfall intensity and cumulative snowfall, the snowfall information at intervals of 6-hours was the most significant.

• 대기
• /
• 제19권2호
• /
• pp.183-198
• /
• 2009

The purpose of this study is to summarize the tropical cyclone (TC) activity of 2008 over the western North Pacific including the verification of the official track and intensity forecast errors of these TCs. The TC activity - frequency, Normalized Typhoon Activity (NTA), and life span - was lower than 58-year (1951-2008) average. 22 tropical cyclones of tropical storm (TS) intensity or higher formed in the western North Pacific and the South China Sea in 2008. The total number is less than 58-year average frequency of 26.4. Out of 22 tropical cyclones, 11 TCs reached typhoon (TY) intensity, while the rest 11 TCs only reached severe tropical storm (STS) and tropical storm (TS) intensity - six STS and five TS storms. One typhoon KALMAEGI (0807) among them affected the Korea peninsula. However, no significant impact - casualty or property damage - was reported. On average of 22 TCs in 2008, the Korea Meteorological Administration (KMA) official track forecast error for 48 hours was 229 km. There was a big challenge for individual cyclones such as 0806 FENGSHEN and 0817 HIGOS presenting significant forecast error, with both intricate tracks and irregular moving speed. The tropical cyclone season in 2008 began in April with the formation of NEOGURI (0801). In May, four TCs formed in the western North Pacific in response to enhanced convective activity. On the other hand, the TC activity was very weak from June to August. It is found that the unusual anti-cyclonic circulation in the lower level and weak convection near the Philippines are dominant during summertime. The convection and atmospheric circulation in the western North Pacific contributed unfavorable condition for TC activity in the 2008 summertime. The 2008 TC activity has continued the below normal state since mid 1990s which is apparent the decadal variability in TC activity.

• 응용통계연구
• /
• 제35권4호
• /
• pp.553-568
• /
• 2022

가계동향조사는 가구에 대한 가계수지 실태를 파악하여 국민 소득·소비 수준과 그 변화의 측정 및 분석 등을 목적으로 하는 통계청의 대표적인 조사이다. 최근 여러 기관들에서 2017년과 2018년의 가계동향 지출부문에서 발생한 시계열 단절에 대한 문제를 인식하고, 이 기간에 대한 시계열 연계를 위한 관련 연구를 진행하고 있다. 본 연구에서는 2016년까지의 가계동향 조사 시계열 특성을 파악하고, 이를 반영하여 2017년과 2018년의 지출액에 대한 시계열을 연계하는 예측값을 도출한다. 본 연구에서는 각 지출 항목들의 시계열적 특성을 골고루 반영하는 동시에 특정 예측 모형의 영향을 줄이기 위하여 총 8개의 회귀모형, 시계열모형, 머신러닝 기법을 합성하여 사용하였다. 특히 본 연구의 주목할 만한 특징은, Top-down 또는 Bottom-up 방식이 아닌, 정보의 손실없이 가계동향조사의 계층 구조를 반영할 수 있는 optimal combination 기법을 사용하여 예측력을 향상시켰다는 점이다. 2017년부터 2019년 자료에 대한 가계동향 지출 부문의 연계 분석 결과, 본 연구가 제안하는 연계 방식이 시계열 단절성 회복 및 예측력 향상에 기여하며, 또한 optimal combination 기법에 의한 계층 조정 후의 예측값이 조사자료에 보다 근접한 결과를 보여줌을 확인하였다.

• Asia Marketing Journal
• /
• 제15권3호
• /
• pp.53-77
• /
• 2013

As advertising and promotions are categorized as operating expenses, managers tend to reduce marketing budget to improve their short term profitability. Gauging the value and accountability of marketing spending is therefore considered as a major research priority in marketing. To respond this call, recent studies have documented that financial market reacts positively to a firm's marketing activity or marketing related outcomes such as brand equity and customer satisfaction. However, prior studies focus on the relation of marketing variable and financial market variables. This study suggests a channel about how marketing activity increases firm valuation. Specifically, we propose that a firm's marketing activity increases the level of the firm's product market information and thereby the dispersion in financial analysts' earnings forecasts decreases. With less uncertainty about the firm's future prospect, the firm's managers and shareholders have less information asymmetry, which reduces the firm's cost of capital and thereby increases the valuation of the firm. To our knowledge, this is the first paper to examine how informational benefits can mediate the effect of marketing activity on firm value. To test whether marketing activity contributes to increase in firm value by mitigating information asymmetry, this study employs a longitudinal data which contains 12,824 firm-year observations with 2,337 distinct firms from 1981 to 2006. Firm value is measured by Tobin's Q and one-year-ahead buy-and-hold abnormal return (BHAR). Following prior literature, dispersion in analysts' earnings forecasts is used as a proxy for the information gap between management and shareholders. For model specification, to identify mediating effect, the three-step regression approach is adopted. All models are estimated using Markov chain Monte Carlo (MCMC) methods to test the statistical significance of the mediating effect. The analysis shows that marketing intensity has a significant negative relationship with dispersion in analysts' earnings forecasts. After including the mediator variable about analyst dispersion, the effect of marketing intensity on firm value drops from 1.199 (p < .01) to 1.130 (p < .01) in Tobin's Q model and the same effect drops from .192 (p < .01) to .188 (p < .01) in BHAR model. The results suggest that analysts' forecast dispersion partially accounts for the positive effect of marketing on firm valuation. Additionally, the same analysis was conducted with an alternative dependent variable (forecast accuracy) and a marketing metric (advertising intensity). The analysis supports the robustness of the main results. In sum, the results provide empirical evidence that marketing activity can increase shareholder value by mitigating problem of information asymmetry in the capital market. The findings have important implications for managers. First, managers should be cognizant of the role of marketing activity in providing information to the financial market as well as to the consumer market. Thus, managers should take into account investors' reaction when they design marketing communication messages for reducing the cost of capital. Second, this study shows a channel on how marketing creates shareholder value and highlights the accountability of marketing. In addition to the direct impact of marketing on firm value, an indirect channel by reducing information asymmetry should be considered. Potentially, marketing managers can justify their spending from the perspective of increasing long-term shareholder value.

• 디지털융복합연구
• /
• 제10권6호
• /
• pp.205-211
• /
• 2012

허베이스피리트호 사고로 인해 원유 $12,547k{\ell}$가 해상에 유출되어 총 4만여 가구의 주민들이 피해를 입었으며, 태안군을 포함한 11개 시 군이 특별재난구역으로 선포되었다. 이러한 대형 유류오염사고는 자연환경파괴 뿐만 아니라 지역의 주변환경 변화에 중대한 영향을 주게 된다. 본 연구에서는 허베이스피리트호 유류오염사고 피해가 가장 큰 지역인 태안을 중심으로 유류오염사고가 피해지역 주변환경에 미치는 영향을 조사 분석하였다. 조사항목은 크게 인구변화, 지역경제변화, 주민건강영향, 지역사회갈등 등으로 구분하여 수행하였다. 이러한 분석결과는 향후 유류사고 발생시 피해지역에 미치는 직 간접적인 영향을 예측하고 정부의 효율적인 정책방안을 수립하는데 매우 중요한 요소로 활용될 수 있을 것이다.

• 한국지역지리학회지
• /
• 제20권4호
• /
• pp.444-453
• /
• 2014

환경위험의 피해가 환경불평등과 사회불평등의 상호작용으로 인해 환경약자가 더 많이 피해를 받게 되는 환경 피해 불평등이 심화될 것으로 전망되고 있다. 본 연구는 서울시를 대상으로 미국 캘리포니아 환경보호청에서 개발한 환경보건 스크리닝 툴을 적용하여 통합적인 지역 규모의 누적영향을 평가하였다. 환경보건 취약지역을 스크리닝하기 위하여 환경노출과 건강영향의 환경부담, 민감집단과 사회경제적 요인의 인구특성에 따라 10개 지표를 선정하였다. 환경보건 스크리닝 툴을 통하여 2009~2011년 서울시 누적영향평가를 실시한 결과, 서울의 강서와 강남지역에서 위험요인이 높게 나타났며 강서지역은 환경부담과 인구특성 모두에서 위험요인이 높았고, 강남지역은 환경부담요인이 높은 것으로 나타났다. 연구결과는 민감 취약계층 등 환경약자를 고려한, 공정하고 효율적인 환경정책을 추진하기 위한 과학적인 근거를 제공할 수 있다.

• 한국해양공학회지
• /
• 제19권4호
• /
• pp.35-41
• /
• 2005

There has been increasing offshore oil exploration, drilling, and production activities, as well as a huge amount of petroleum being transported by tankers and pipelines through the ocean and costal environment. Assessment must be made of the potential risk of damage resulting from the exploration, development and transportation activities. This is achieved through predictive impact evaluations of the fate of hypothetical or real oil spills. VVhen an oil spill occurs, planning and execution of cleanup measures also require the capability to forecast the short-term and long-term behavior of the spilled oil. A great amount of effort has been spent by government agencies, oil industries, and researchers over the past decade to develop more realistic models for oil spills. Numerous oil spill models have been developed and applied, most of which attempt to predict the oil spill fate and behavior. For an actual contingency planning, the oil fate and behavior model should be combined with an oil spill incident model, an environmental impact and risk model and a contingency planning model. The purpose of this review study is to give an overview of existing oil spill models that deal with the physical, chemical, biological, and socia-economical aspects of the incident, fate, and environmental impact of oil spills. After reviewing the existing models, future research needs are suggested. In the study, available oil spill models are separated into oil spill incident, oil spill fate and behavior, environmental impact and risk, and contingency planning models. The processes of the oil spill fate and behavior are reviewed in detail and the characteristics of existing oil spill fate and behavior models are examined and classified so that an ideal model may be identified. Finally, future research needs are discussed.

• 한국항만경제학회지
• /
• 제32권2호
• /
• pp.25-37
• /
• 2016

1990년대 이후 한국 경제는 두 번의 금융위기(1997년 아시아 금융위기와 2008년 글로벌 금융위기)를 겪었다. 이들 금융위기는 한국 실물경제의 여러 지표에 영향을 끼쳤고 이로 인해 한국의 최대 수출입 관문인 부산항에서 처리되는 물동량 변화에도 영향을 주었다. 그러나 아시아 금융위기 당시 부산항의 총 컨테이너처리실적을 살펴보면 금융위기와 관련된 영향이 명백히 나타나고 있지 않다. 이 연구는 이들 금융위기가 부산항 물동량 변화에 끼친 영향을 분석하기 위해 ARIMA모형의 특수한 형태 중 하나인 개입모형을 이용하였다. 개입모형은 시계열 예측뿐만 아니라 특정 사건발생과 관련된 그 효과를 분석하기 위하여 사용되는 정량적 모형으로 이 연구에서는 개입효과의 추정에 중점을 두었다. 그 결과 부산항 물동량 변화에 두 번의 금융위기가 유의미한 영향을 미쳤다는 것을 보였다.

• 대기
• /
• 제31권4호
• /
• pp.445-459
• /
• 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.

• 전기학회논문지
• /
• 제67권2호
• /
• pp.158-164
• /
• 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.