• 대기
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• 제34권2호
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• pp.107-121
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• 2024

In this study, we empirically analyzed the impact of physical risks due to climate change on the soundness and operational performance of the financial industry by combining economics and climatology. Particularly, unlike previous studies, we employed the Seasonal-Trend decomposition using LOESS (STL) method to extract trends of climate-related risk variables and economic-financial variables, conducting a two-stage empirical analysis. In the first stage estimation, we found that the delinquency rate and the Bank for International Settlement (BIS) ratio of commercial banks have significant negative effects on the damage caused by natural disasters, frequency of heavy rainfall, average temperature, and number of typhoons. On the other hand, for insurance companies, the damage from natural disasters, frequency of heavy rainfall, frequency of heavy snowfall, and annual average temperature have significant negative effects on return on assets (ROA) and the risk-based capital ratio (RBC). In the second stage estimation, based on the first stage results, we predicted the soundness and operational performance indicators of commercial banks and insurance companies until 2035. According to the forecast results, the delinquency rate of commercial banks is expected to increase steadily until 2035 under assumption that recent years' trend continues until 2035. It indicates that banks' managerial risk can be seriously worsened from climate change. Also the BIS ratio is expected to decrease which also indicates weakening safety buffer against climate risks over time. Additionally, the ROA of insurance companies is expected to decrease, followed by an increase in the RBC, and then a subsequent decrease.

• 한국습지학회지
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• 제3권1호
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• pp.49-59
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• 2001

The objective of this study is to provide the results of frequency analysis for Dong-eup reservoir, in which the environmental and ecological roles in addition to the water supply and flood control capacity of the reservoir are increased rapidly. The suggested results are the frequency analysis of annual maximum rainfall data based on eight different rainfall duration data at Masan and Milyang raingauge stations. We also provide the probabilistic inflows from subbasins and evaluate the stage increases of the reservoir. As results, the 24-hour and 100-year return period rainfall is 291.8 mm and consequently inflows are 361.79 cms for Junam, 192.57 for Sannam and 408.28 for Dongpan reservoirs. The 24-hour and 100-year return period reservoir stages are expected as 5.08 m, 5.51 m and 6.89 m depending on the initial reservoir stage. The suggested results of frequency analysis of rainfalls, inflows and reservoir stages in this study will be useful for the scientific and systematic management of the reservoir.

• 전기학회논문지
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• 제67권4호
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• pp.554-560
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• 2018

Since Korea has a small land area, it is expected to construct the conductor return type with neutral wire in the case of ${\pm}500kV$ HVDC double bipole transmission line. Therefore, in order to apply ${\pm}500kV$ HVDC double bipole transmission line with neutral wire in Korea, it is necessary to develop technology for insulation and environmental designs. In this study, radio interference, audible noise, electric field and ion current density according to the polarity arrangement were compared and assessed in the ${\pm}500kV$ HVDC double bipole transmission line with the conductor return method. And the optimum configuration of HVDC double bipole transmission line was determined from the viewpoint of electrical environment.

• Management Science and Financial Engineering
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• 제10권1호
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• pp.25-41
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• 2004

There have been many studies to build a model that can help investors construct optimal portfolio. Most of the previous models, however, are based upon the path-breaking Markowitz model (1959) which is a quantitative model. One of the most important problems with that kind of quantitative model is that, in reality, most of the investors use not only quantitative, but also qualitative information when they select their optimal portfolio. Since collecting both types of information from the markets are time consuming and expensive, making a set of target assets smaller, without suffering heavy loss in the rate of return, would attract investors. To extract only desired assets among all available assets, we need knowledge that identifies investors' preference for the risk of the assets. This study suggests two-layer decision-making rules capable of identifying an investor's risk preference and an architecture applying them to a quantitative portfolio model based on risk and expected return. Our knowledge-based portfolio system is to build an investor's preference-oriented portfolio. The empirical tests using the data from Korean capital markets show the results that our model contributes significantly to the construction of a better portfolio in the perspective of an investor's benefit/cost ratio than that produced by the existing portfolio models.

• 한국음향학회지
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• 제18권4호
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• pp.11-16
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• 1999

본 논문에서는 CHUKOH사의 CGP-500 PTFE 기판상에(유전율 2.6, 두께 1.6mm(±0.08)) 접지판의 폭과 방사 패치의 폭이 동일한 850MHz 대의 QMSA(Quarter-Wavelength Microstrip Antenna)를 설계·제작하였다. 실험에 의하여 가장 양호한 급전점을 선정하여 프로브 급전한 다음, 방사 패치와 그라운드 판과의 간격 L₃을 단계적으로 5mm씩 잘라가면서 QMSA의 공진 주파수와 반사 손실을 측정하였다. 그 결과, 간격 L₃이 좁아질수록, 특히 10mm 이하에서는 예상과 달리 공진 주파수는 증가하고 반사 손실은 감소하는 것을 알 수 있었다.

• 한국ITS학회 논문지
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• 제6권3호
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• pp.101-110
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• 2007

본 논문에서는 UHF대역의 RFID 리더기용 원형편파 안테나를 설계 제작하였다. 그리고 설계 제작된 안테나의 성능분석을 통하여 Return Loss (S11)는 914 MHz에서 약 -45.529 dB로 상당히 적었으며, 안테나 이득은 약 6.09 dBi값을 얻었다. 또한 임피던스 매칭은 약 $50.48\;{\Omega}$이고, 사용 대역 중심 주파수인 911 MHz에서 축비는 1.2 dB로 설계되어 모든 RFID 리더기에 적용 가능함을 확인하였다. 따라서 RFID 리더기의 파라미터에서 가장 중요한 것 중 하나는 수신감도를 향상시켜서 원거리에서도 멀티태그를 인식하는데 있어서 원형편파 안테나의 이득을 높게 설계 제작함으로써 감도를 향상 시킬 것으로 기대 된다.

• 설비공학논문집
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• 제29권1호
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• pp.38-42
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• 2017

This study proposes an idea for energy saving in apartment machine rooms. A conventional district heating system is equipped with constant-flow pumps and bypass valves to regulate pump differential pressure. Each family unit is equipped with a constant-flow on/off valve. This leads to excessive hot water circulation and a high return temperature. To reduce energy loss, this study assumes that each family unit is renovated with a heating valve which regulates the return temperature at $35^{\circ}C$. The hot water supply pump is also replaced with a pump with an inverter to vary flow rate. Expected energy savings is then estimated from field test data. According to the results, pump electricity consumption was reduced by 6,100 kWh for a family unit building over about half a year. The supply temperature can also be lowered by $5^{\circ}C$, which can contribute to a production of electricity of 10.3 kWh/ton of hot water.

• 한국통신학회논문지
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• 제37권1C호
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• pp.17-23
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• 2012

RFID(Radio Frequency IDentification)는 바코드를 대체해 많은 분야에서 각광을 받고 있으나, 현재까지는 적용 범위가 유통관리, 판매 등의 한정된 산업 분야에서 주로 이용되어 왔다. 본 논문에서는 RFID 시스템을 실제 공정과정에 적용할 경우의 운영 방안 및 효과에 대한 연구 결과를 기술하였다. 아울러 RFID 시스템의 도입 전과 후의 비용 관점에서의 비교 분석 결과, RFID 시스템의 운용 이후 이에 투자되는 비용 상쇄는 물론 그 이상의 효과가 있음을 확인 하였다. 따라서 본 연구 결과는 바코드 시스템에서 RFID 시스템으로의 교체를 망설이는 많은 제조업체들의 의사결정에 크게 기여할 수 있을 것으로 기대된다.

• 산업경영시스템학회지
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• 제34권2호
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• pp.35-48
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• 2011

In this paper, we have studied the impact of adopting XBRL (eXtensible Business Reporting Language) on information asymmetry in capital markets with the additional research on the usefulness of XBRL data how to improve the quality of accounting information. From the Kosdaq XBRL service, the samples are selected including 38 adopted companies and the 30 non-adopted companies for the paired analysis. The daily stock return volatility (VOLA) as independent variable and other several controlling variables have been added for the regression analysis to measure the impact on information asymmetry in capital markets. he analytical result indicated that the asymmetry hypotheses that XBRL data will give a significant impact on the capital market and will reduce the volatility, which are expected in the hypotheses. This is the first analytical research on the capital market and its impacts to the capital market from adopting XBRL based accounting information. Additionally, the analysis showed the impacts on the reporting cycle of accounting information and its usefulness of accounting data itself.

• Journal of information and communication convergence engineering
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• 제13권2호
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• pp.81-85
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• 2015

A 94-GHz phased array antenna using a log-periodic antenna has been developed on a GaAs substrate. The developed phased array antenna comprises four log-periodic antennas, a phase shifter, and a Wilkinson power divider. This antenna was fabricated using the standard microwave monolithic integrated circuit (MMIC) process including an air bridge for unipolar circuit implementations on the same GaAs substrate. The total chip size of the fabricated phased array antenna is 4.8 mm × 4.5 mm. Measurement results showed that the fabricated phased array antenna had a very wide band performance from 80 GHz to 110 GHz with return loss characteristics better than -10 dB. In the center frequency of 94 GHz, the fabricated phased array antenna showed a return loss of -16 dB and a gain of 4.43 dBi. The developed antenna is expected to be widely applied in many applications at W-band frequency.