• Journal of Korea Society of Industrial Information Systems
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• v.7 no.3
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• pp.54-61
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• 2002

A remote image transmission apparatus combines robot technology and image transmission there is safe problem or place that a person can not go. Recently, control apparatus that use wire and RF between web server and robot for remote control are developed. But there is problem that must install internet line and communication distance. Transmission distance problem call solve when using the equipment of RF, but price of RF router is problem that is very high cost. In this paper, we developed remote control system using the CDMA cellular phone communication network that can control image transmission and image transmission apparatus to solve these problem. Developed system could solve defects of methods that use existent RF and internet. And could transmit the most suitable image and voice under limited condition include current communication network.

• Environmental and Resource Economics Review
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• v.9 no.5
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• pp.925-945
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• 2000

This paper analyses the impact of energy-saving investment on Greenhouse gas emissions using a model of energy demand in Korea. SUR method was employed to estimate the demand equation. The econometric estimates provide information about the energy price divisia index, sector income, and energy saving-investment elasticities of energy demand. Except for energy price divisia, the elasticities of each variable are statistically significant. Also, the price and substitution elasticities of each energy price are similar to the results reported by the previous studies. The energy-saving investment is statistically significant and elasticities of each sector is inelastic. Using the coefficient of energy-saving investment and carbon transmission coefficient, the amount of reduction of energy demand and the reduction of carbon emissions can be estimated. The simulation is performed with the scenario that the energy-saving investment increase by 10~50%, keeping up with Equipment Investment Plan of 30% increase in energy-saving investment by 2000. The results show that the reduction of energy demand measured as 11.2% based upon 1995's level of the energy demand, in industrial sector. Accordingly, the carbon emissions will be reduced by 11.3% based upon 1995's level of the carbon emissions in industrial sector.

• Asia-Pacific Journal of Business
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• v.15 no.3
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• pp.385-397
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• 2024

Purpose - The purpose of this study was to analyze the dynamic relationship between oil prices and macroeconomic variables (gross domestic product, consumer price index, and interest rate). Long-run and short-run effects of oil prices on these macroeconomic variables are examined. Design/methodology/approach - The vector error correction model (VECM) is used to examine the short-run and long-term causality of oil prices, and a hierarchical Bayesian vector autoregressive model (HBVAR) is used to find the impulse of oil shock and the response of other variables. Findings - First, oil prices do not have short-term causality with macroeconomic variables, but they have long-term causality with interest rates and GDP. Second, the long-term stable relationship of oil prices and other macroeconomic variables is important to find out causality. Third, oil shock increases interest rates and decreases GDP and consumer price. Research implications or Originality - The significance of this study is a new attempt to analyze the dynamic relationship between oil prices and macroeconomic variables by linking VECM and HBVAR. Although VECM can analyze the long-term relationship and short-term dynamics between oil prices and macroeconomic variables, it was difficult to identify the transmission path of the oil price shock. HBVAR is confirmed to be flexible because it can bypass the process of selecting VAR or VECM through unit root test and cointegration analysis, and it is expected to reduce uncertainty of selecting hyperparameters.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.11B
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• pp.1207-1215
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• 2009

The FTTH is known as an optimal solution to provide broadband services like IPTV and the W-PON is a good alternative to implement the FTTH. It is firstly commercialized in Korea but not widely deployed because of it's high price. In this paper, we suggest a wavelength integration method to drop the price and enhance the utilization of the W-PON. The method makes one logical channel with multiple wavelengths when the W-PON system has to accommodate a signal of which transmission rate is greater than the rate of a single wavelength. Accordingly, the system can accommodate any signal rate. We introduce a frame structure, suggest synchronization and clock recovery methods, and finally show actual applications for the Ethernet and the G-PON.

• Proceedings of the KIEE Conference
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• 2005.07a
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• pp.855-857
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• 2005

Transmission congestion is one of the Key factor to local market power in competitive electricity markets. Financial transmission rights provide the financial protection to their holders by paying back the congestion cost. However, the market participants who have market power can exacerbate their market power. This paper analyzes the effect of exercising local market power with the rights on the market price. The proposed methodology was demonstrated with the Optimal Power Flow(OPF). Case study is fulfilled by GAMS simulation. The simulation are condusted in case of Nodal Pricing.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.49 no.5
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• pp.220-225
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• 2000

As a competition is introduced in the electricity supply industry, a congestion problem arises in the transmission network. The congestion causes the transmission cost to increase. One way to decrease the congestion cost is to control the transmission flow through the installation of TCSC(Thyrister Controlled Series Capacitor). This paper deals with the optimal site of the TCSC for reducing the congestion cost using a shadow price which is one of the economic signals for the systems. Test results show that the site of the TCSC is optimal to minimize the congestion cost by the proposed algorithm.

• Journal of Biosystems Engineering
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• v.22 no.4
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• pp.497-502
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• 1997

Automation facilities of greenhouses have been continuously developed. However, the conventional two-stage worm gear reducer reveals some problems, including low transmission efficiency. The worm gear reducer also have some difficulties in manufacturing and short life. Therefore, this study was performed to develop a planetary gear reducer, having a high Sear reduction ratio and high torque transmission efficiency. The planetary gear system consisted of a fixed ring gear and a 2-teeth differential ring gear turning slow, as the planetary pinion orbits fast around the fixed ring gear. The developed gear system can achieve a high speed reduction rate at one stage. The reducing system was employed to the greenhouse ventilation system. The reducer has the transmission efficiency of 70.5%, 2∼3 times longer life time, and twofold roll-up torque at an affordable price, comparing with conventional reducers. This reducer can be also applied to many industrial equipments, such as industrial crane, hoist, elevator and gondola etc.

• KIEE International Transactions on Power Engineering
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• v.11A no.4
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• pp.21-26
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• 2001

As competition is introduced in the electricity supply industry, congestion becomes a more important issue. Congestion in a transmission network occurs due to an operating condition that causes limit violations on the transmission capacities. Congestion leads to inefficient use of the system, or causes additional costs (Congestion cost). One way to reduce this inefficiency or congestion cost is to control the transmission flow through the installation of UPFC (Unified Power Flow Controller). This paper also deals with an optimal siting of the UPFC for reducing congestion cost by using shadow prices. A performance index for an optimal siting is defined as a combination of line flow sensitivities and shadow prices. The proposed algorithm is applied to the sample system with a condition, which is concerning the quadratic cost functions. Test results show that the siting of the UPFC is optimal to minimize the congestion cost by the proposed algorithm.

• Journal of Korea Multimedia Society
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• v.18 no.1
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• pp.25-34
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• 2015

Recently, in distribution market, demand for electronic shelf label system is increasing gradually to provide the accurate price immediately and detailed product information to consumers and reduce operation costs. Most of electronic shelf label system companies develop the full-graphic display device to display a wide variety of product information as well as the exact price. Our system had introduced Go-Back-N retransmission method in the early. However, we encountered performance problems that it delayed updating of the electronic shelf label system and exhausted the battery life time. Proposed adaptive image retransmission technique based on the selective scheme is that tags of electronic shelf label system recognize idle time of transmission cycle and require partial image retransmission to sever by itself. As a result, it can acquire much more opportunities of partial image retransmission within the same period and increase reception rate of full image for each tags. The experimental result shows that adaptive image retransmission technique's reception rate of full image for each tags is approximately 4% higher than existing previous works. And total battery life time increases 30 hours because tag reduce wake-up time as it receive only lost data instead of whole data.

• Management & Information Systems Review
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• v.32 no.4
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• pp.189-207
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• 2013

Using high-frequency data for 2 years, this study investigates intraday lead-lag relationship between stock index and stock index futures markets in Korea and China. We found that there are some differences in price discovery and volatility transmission between Korea and China after the stock index futures markets was introduced. Following Stoll-Whaley(1990) and Chan(1992), the multiple regression is estimated to examine the lead-lag patterns between the two markets by Newey-West's(1987) heteroskedasticity and autocorrelation consistent covariance matrix(HAC matrix). Empirical results of KOSPI 200 shows that the futures market leads the cash market and weak evidence that the cash market leads the futures market. New market information disseminates in the futures market before the stock market with index arbitrageurs then stepping in quickly to bring the cost-of-carry relation back into alignment. The regression tests for the conditional volatility which is estimated using EGARCH model do not show that there is a clear pattern of the futures market leading the stock market in terms of the volatility even though controlling nonsynchronous trading effects. This implies that information in price innovations that originate in the futures market is transmitted to the volatility of the cash market. Empirical results of CSI 300 shows that the cash market is found to play a more dominant role in the price discovery process after the Chinese index started a sharp decline immediately after the stock index futures were introduced. The new stock index futures markets does not function well in its price discovery performance at its infancy stage, apparently due to high barriers to entry into this emerging futures markets. Based on EGAECH model, the results uncover strong bi-directional dependence in the intraday volatility of both markets.