• 한국수자원학회:학술대회논문집
• /
• 한국수자원학회 2020년도 학술발표회
• /
• pp.183-183
• /
• 2020

Accurate quantitative precipitation estimation plays an important role in hydrological modelling and prediction. Instantaneous quantitative precipitation estimation (QPE) by utilizing the weather radar data is a great applicability for operational hydrology in a catchment. Previously, regression technique performed between reflectivity (Z) and rain intensity (R) is used commonly to obtain radar QPEs. A novel, recent approaching method which might be applied in hydrological area for QPE is Long Short-Term Memory (LSTM) Networks. LSTM networks is a development and evolution of Recurrent Neuron Networks (RNNs) method that overcomes the limited memory capacity of RNNs and allows learning of long-term input-output dependencies. The advantages of LSTM compare to RNN technique is proven by previous works. In this study, LSTM networks is used to estimate the quantitative precipitation from weather radar for an urban catchment in South Korea. Radar information and rain-gauge data are used to evaluate and verify the estimation. The estimation results figure out that LSTM approaching method shows the accuracy and outperformance compared to Z-R relationship method. This study gives us the high potential of LSTM and its applications in urban hydrology.

• Clinical and Experimental Pediatrics
• /
• 제61권5호
• /
• pp.150-155
• /
• 2018

Purpose: Infantile spasms, also known as West syndrome, is an age-specific epileptic seizure. Most patients with this condition also exhibit delayed development. This study aimed to determine the effect of long-term prenatal stress on susceptibility to infantile spasms. Methods: We subjected pregnant rats to acute or chronic immobilization stress. Resulting offspring received N-methyl-D-aspartic acid (15 mg/kg, intraperitoneally) on postnatal day 15, and their behaviors were observed 75 minutes after injection. The expression of KCC2 and GAD67 was also determined using immunohistochemistry. Results: Exposure to long-term prenatal stress increased the frequency of spasms and decreased the latency to onset of spasms compared with offspring exposed to short-term prenatal stress. Expression of KCC2 and GAD67 also decreased in the group exposed to long-term prenatal stress compared with the group exposed to short-term prenatal stress. Conclusion: Our study suggests that exposure to long-term prenatal stress results in increased susceptibility to seizures.

• 대한원격탐사학회지
• /
• 제36권4호
• /
• pp.515-525
• /
• 2020

This study investigates the potential of bidirectional long short-term memory (Bi-LSTM) for efficient modeling of temporal information in crop classification using multitemporal remote sensing images. Unlike unidirectional LSTM models that consider only either forward or backward states, Bi-LSTM could account for temporal dependency of time-series images in both forward and backward directions. This property of Bi-LSTM can be effectively applied to crop classification when it is difficult to obtain full time-series images covering the entire growth cycle of crops. The classification performance of the Bi-LSTM is compared with that of two unidirectional LSTM architectures (forward and backward) with respect to different input image combinations via a case study of crop classification in Anbadegi, Korea. When full time-series images were used as inputs for classification, the Bi-LSTM outperformed the other unidirectional LSTM architectures; however, the difference in classification accuracy from unidirectional LSTM was not substantial. On the contrary, when using multitemporal images that did not include useful information for the discrimination of crops, the Bi-LSTM could compensate for the information deficiency by including temporal information from both forward and backward states, thereby achieving the best classification accuracy, compared with the unidirectional LSTM. These case study results indicate the efficiency of the Bi-LSTM for crop classification, particularly when limited input images are available.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2004년도 추계학술대회 논문집 전력기술부문
• /
• pp.97-100
• /
• 2004

As the circumstance of the traditional system is changed according to power system deregulation, the simulation tool which should reflect market code providing market operating mechanism is needed to analyze an electricity market. This paper presents the development of Electricity Market Price Simulator for short term(EMPS) that is designed to imitate the Korean electricity market. The EMPS is developed in VB.NET and is composed if three functions that consist of calculating SMP for CBP market, MCP for TWBF market and LMP for LMP-market. To evidence the features and the performance of EMPS, a small two way bidding market with 12-bus system, one way bidding market for generator competition and LMP market with 5-bus system will be presented for the electricity market simulations using EMPS.

• STI Policy Review
• /
• 제9권1호
• /
• pp.55-76
• /
• 2018

This study analyzed the effect of the government R&D subsidy program on long-term firm survival. In order to estimate the average treatment effect for the treated group, we used the survival analysis and matching method by constituting a comprehensive dataset of more than 90,000 observations. The analysis results show that the government R&D subsidy has a negative impact on long-term firm survival. In particular, not only the subsidy does not have a statistically significant effect on firm survival in the relatively short-term, the survival probability of the subsidized firms is statistically significantly lower than the non-subsidized firms after six years. These results can be seen as weakening the justification of government R&D support. There may be problems in the subsidy policy itself and the process of selection of subsidy awardees; however, the more fundamental problem is that the subsidy policy is concluded as the one-time event. Admittedly, it would be difficult for the government to precisely manage the subsidized projects over a long term period. However, in the case of a project in which short-term performance is detected, it would be necessary to provide a step-by-step support to strengthen the firm's competitiveness through further support and continuous development of performance. Of course, mid- and long-term evaluations of subsidy support policy should be performed in parallel with such phased support.

• 한국수자원학회논문집
• /
• 제49권1호
• /
• pp.41-49
• /
• 2016

본 연구에서는 일강수량의 누적 패턴을 고려하여 새로운 가뭄지수(RADI)를 개발하였다. RADI는 누적 강수량의 장기간의 평균과 특정 기간에 관측된 누적 강수량을 비교하여 일단위로 가뭄지수를 간단히 산정할 수 있도록 개발되었다. 우리나라의 대표적인 가뭄기간 동안의 RADI의 시 공간적 변동성과 재현 주기를 살펴봄으로써 장 단기 가뭄의 감시에 대한 RADI의 적용성을 평가하였다. SPI의 경우, 장 단기 가뭄을 표현하기 위해서는 여러 가지 지속기간을 가지는 SPI를 사용해야 하지만, RADI는 하나의 지수로 단기 및 장기가뭄을 표현하고 모니터링 할 수 있다. RADI의 전국 평균값을 살펴본 결과, 우리나라에서 20년 주기로 가뭄이 발생하고 있다는 사실을 확인하였다. 또한 RADI의 발생확률 및 통계 분석을 통해 5단계의 가뭄 등급을 제안하였으며, 이는 가뭄 예보와 대응을 위한 기준으로 활용될 수 있을 것으로 판단된다.

• 한국대기환경학회:학술대회논문집
• /
• 한국대기환경학회 2005년도 추계학술대회 논문집
• /
• pp.391-393
• /
• 2005

• 한국방재학회:학술대회논문집
• /
• 한국방재학회 2009년도 정기 학술발표대회
• /
• pp.140.1-140.1
• /
• 2009

• The Journal of Asian Finance, Economics and Business
• /
• 제7권12호
• /
• pp.21-31
• /
• 2020

This study investigates the dynamic effects of economic development, international cooperation, electricity consumption, and political risk on the escalation of CO₂ emission in Vietnam. We adopted autoregressive distributed lag model and Granger causality method to examine the interaction between CO₂ and various economic and political factors, including foreign direct investment, trade openness, economic growth, manufacture, electricity consumption, and political risk in Vietnam since the economic revolution in 1986. The findings reflect opposite influence between these factors and the level of CO₂ in the intermediate and long-term durations. Accordingly, foreign direct investment and CO₂ emission have a bidirectional relationship, in which foreign direct investment accelerates short-term CO₂ emission, but reduces it in the long run through an interactive mechanism. Moreover, economic development increases the volume of CO₂ emission in both short and long run. There was also evidence that political risk has a negative effect on the environment. Overall, the findings confirm lasting negative environmental effects of economic growth, trade liberalization, and increased electricity consumption. These factors, with Granger causality, mutually affect the escalation of CO₂ in Vietnam. In order to control the level of CO₂, more efforts are required to improve administrative transparency, attract high-quality foreign investment, and decouple the environment from economic development.

• 한국수정란이식학회지
• /
• 제29권2호
• /
• pp.133-139
• /
• 2014

$K^+$ channels are involved in the regulation of a variety of physiological functions, including proliferation, apoptosis and differentiation, in mammalian cells. Our previous study demonstrated that the blockage of $K^+$ channels inhibits mouse early embryonic development. This study was designed to identify the effect of $K^+$ channels during bovine embryonic development. $K^+$ channel blockers (tetraethylammonium (TEA), $BaCl_2$, quinine, ruthenium red and fluoxetine) were added to the culture medium during in vitro fertilization (IVF) for 6 h to first identify the short-term effect of these chemicals. Among $K^+$ channel blockers, fluoxetine, which is used as a selective serotonin reuptake inhibitor, significantly increased the blastocyst formation rate by approximately 6% when compared to control. During the in vitro maturation (IVM) of immature oocytes and the in vitro culture (IVC) of embryos, the oocytes and embryos were exposed to fluoxetine for either a short-term (6 h) or a long-term (24 h) to compare the embryonic development in response to exposure time. The 6 h exposure to fluoxetine during IVM did not affect the blastocyst formation rate, but the rate of blastocyst formation was reduced after the 24 h exposure. On the other hand, embryonic development increased approximately 10% in both groups of embryos exposed to fluoxetine for 6 and 24 h during IVC. Taken together, fluoxetine treatment during IVF and IVC, but not IVM, enhances bovine embryonic development. These results suggest that fluoxetine-modulated signals in oocytes and embryos could be an important factor towards enhancing bovine embryonic development.