• Proceedings of the KIEE Conference
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• 1998.07g
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• pp.2480-2482
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• 1998

In this paper, the implementation of dual rate ADPCM using G.723 16Kbps and 40Kbps speech codec algorithm is handled. For small signals, the low rate 16Kbps coding algorithm shows the same SNR as the high rate 40Kbps coding algorithm, while the low rate 16Kbps coding algorithm shows the lower SNR than the high rate 40Kbps coding algorithm for large signal. To obtain the good trade-off between the data rate and synthesized speech quality, we applied low rate 16Kbps for the small signal and high rate 40Kbps for the large signal. Various threshold values determining the rate are tested for good trade off data rate and speech quality. Also the low pass filter effect of speech input and output devices is simulated at several cut-off frequencies. To simulation result shows the good speech quality at a low rate comparing with 16Kbps & 40Kbps.

• Journal of the Korean Society for Heat Treatment
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• v.25 no.1
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• pp.14-21
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• 2012

The effects of cutting condition and tempering temperature for the shape of cutting chip were investigated. For this purpose, a lead-free brass containing 1wt.% of Bi extruded at $750^{\circ}C$ in straight turning was used in this study. The cutting chip preferred was mainly found to be loose form of arc chips with curling discontinuity, and these were formed by shear fracture. However, some of fragmental element chip were found to be mixed when tempering temperature was as high as $500^{\circ}C$. The form and size of chip was more affected by feed rate than by tempering temperature and cutting rate. In addition, the cutting surface was observed to be formed more rough in the case of high feed rate and low cutting rate compared to low feed rate and high cutting rate.

• Nuclear Engineering and Technology
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• v.33 no.1
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• pp.83-92
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• 2001

The properties of off-gas generated from vitrification process of ion-exchange resin were characterized. Theoretical composition and flow rate of the off-gas were calculated based on chemical composition of resin and it＇s burning condition inside CCM. The calculated off-gas flow rate was 67.9Nm$^3$/h at the burning rate of 40kg/h. And the composition of off-gas was avaluated as $CO_2$(41.4%), steam(40.0%), $O_2$(13.3%), NO(3.6%), and SO$_2$(1.6%) in order. Then, actual flow rate and composition of off-gas were measured during pilot-scale demonstration tests and the results were compared with theoretical values. The actual flow rate of off-gas was about 1.6 times higher than theoretical one. The difference between theoretical and actual flow rates was caused by the in-leakage of air to the system, and the in-leakage rate was evaluated as 36.3Nm$^3$/h. Because of continuous change in the combustion parameters inside CCM, during demonstration tests, the concentration of toxic gases showed wide fluctuation. However, the concentration of CO, a barometer of incompleteness of combustion inside CCM, was stabilized soon. The result showed quasi-equilibrium state was achieved two hours after feeding of resin.

• ETRI Journal
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• v.30 no.2
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• pp.261-267
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• 2008

In this paper, we propose and demonstrate a cost-effective technique to upgrade the capacity of dense wavelength division multiplexing (DWDM) networks to a 40 Gb/s line rate using the existing 10 Gb/s-based infrastructure. To accommodate 40 Gb/s over the link optimized for 10 Gb/s, we propose applying a combination of super-FEC, carrier-suppressed return-to-zero, and pre-emphasis to the 40 Gb/s transponder. The transmission of 40 Gb/s DWDM channels over existing 10 Gb/s line-rate long-haul DWDM links, including $40{\times}40$ Gb/s transmission over KT's standard single-mode fiber optimized for 10 Gb/s achieves successful results. The proposed upgrading technique allows the Q-value margin for a 40 Gb/s line rate to be compatible with that of 10 Gb/s.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.6
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• pp.676-686
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• 2016

This study analyzed the long term relationship between the K-REITs' lending rate and interest rate variables based on ARDL (autoregressive distributed lag) and also examined the short term relationship based on the ARDL-ECM model. In the results of the empirical test, there is a co-integration relationship among the K-REITs' lending rate, 3 year government bond (rate), 3 year government bond (rate), corporation bond (rate) (AA-, 3year) and general fund loan rate. This means that the K-REITs' lending rate is related to the long term interest rate. The corporate general fund loan rate has a significant correlation with the K-REITs' lending rate in the long term relation and short term adjustment process. The establishment of a management plan by the REITs considering the trends in the corporate general fund loan rate in the decision making process for finance sector borrowings can be practically helpful for the K-REITs.

• Proceedings of the KIEE Conference
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• 2009.04b
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• pp.253-255
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• 2009

박막태양전지에서 빛을 처음 받아들이는 p-layer는 전체적인 태양전지 특성에 큰 영향을 준다. 본 논문에서는 p-layer의 gas flow rate를 가변하여 증착한 P-I-N cell을 통해 DIV를 측정하고 분석하였다. 더불어 gas flow rate에 따른 p-layer의 특성변화를 토대로 시뮬레이션을 진행하여 실제 소자와 비교하여 보았다. simulation da와 experimental data를 비교해보면 전체적으로 유사한 경향성을 보이며 saturation current는 큰 차이를 보이지 않았으나 ideality factor와 series resistance에서 real device가 비교적 큰 값을 나타내는 것을 볼 수 있었다. 본 연구는 simulation data를 기반으로 real device를 제작하는데 큰 도움이 될 것이다.

• IE interfaces
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• v.18 no.2
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• pp.205-220
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• 2005

This study presents a web log analysis model for e-CRM, which combines the on-line customer's purchasing pattern data and transaction data between companies in B2B environment of make-to-order company. With this study, the customer evaluation and the customer subdivision are available. We can forecast the estimate demands with periodical products sales records. Also, the purchasing rate per each product, the purchasing intention rate, and the purchasing rate per companies can be used as the basic data for the strategy for receiving the orders in future. These measures are used to evaluate the business strategy, the quality ability on products, the customer's demands, the benefits of customer and the customer's loyalty. And it is used to evaluate the customer's purchasing patterns, the response analysis, the customer's secession rate, the earning rate, and the customer's needs. With this, we can satisfy various customers' demands, therefore, we can multiply the company's benefits. And we presents case of the 'H' company, which has the make-to-order manufacture environment, in order to verify the effect of the proposal system.

• East Asian Journal of Business Economics (EAJBE)
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• v.6 no.3
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• pp.24-36
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• 2018

Purpose - From establishing China-Japan diplomatic relations in 1972, the relations between two states has improved a lot, from which makes the government and the people reap much benefit. Owing to this reason, this paper aims at exploiting the impact of exchange rate volatility of RMB on China's foreign direct investment to Japan. Research design and methodology - The quarterly time series data from 2003 to 2016 will be employed to conduct an empirical analysis under the vector error correction model. Meanwhile, a menu of estimated methods such the Johansen co-integration test and the Granger Causality test will be also used to explore the impact of exchange rate volatility of RMB on China's foreign direct investment to Japan. Results - The empirical analysis results exhibit that the real exchange rate has a positive effect on China's foreign direct investment to Japan in the long run. Conversely, the real exchange rate volatility of RMB, the trade openness and the real GDP have a negative effect on China's foreign direct investment to Japan in the long run. However, in the short run, the China's foreign direct investment to Japan, the real exchange rate, the trade openness and the real GDP in period have a negative effect on China's foreign direct investment to Japan in period. Oppositely, the real exchange rate volatility of RMB in period has a positive effect on China's foreign direct investment to Japan in period. Conclusions - From the empirical evidences in this paper provided, it can be concluded that an increase in the exchange rate volatility of RMB can result in a decrease in the China's foreign direct investment to Japan in the long run. However, an increase in the exchange rate volatility of RMB can lead to an increase in the China's foreign direct investment to Japan in the short run. Therefore, the China's government should have a best control of the real exchange rate volatility of RMB so as to improve China's foreign direct investment to Japan.

• Journal of the korean Society of Automotive Engineers
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• v.5 no.1
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• pp.32-44
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• 1983

In case of $K_{Imax}$ < $K_{Iscc}$, the corrosion fatigue of high strength steel in 0.1N $H_{2}$S $O_{4}$ solution and 3.5% salt water is as follows. 1. The fatigue life shortens in order of 3.5% salt water and 0.1N $H_{2}$S $o_{4}$ solution. 2. The fatigue crack growth rate in air is obtained as the following equation. (dc/dN)$_{atr}$=7.23*10$^{-6}$ (.DELTA. K)$^{2.23}$ 3. The corrosion fatigue crack growth rate in environment is divided into three regions, that is, First Region, Second Region and Third Region from the small cyclic stress intensity. 4. The formation rate of the active surface on metal is slower than the mechano-chemical reaction rate in First Region. The crack growth rate depends on time and the cyclic stress intensity and is expressed as the following equation. (dc/dN)$_{I}$=C(/DELTA. K)$^{\delta}$ 5. The formation rate of the active surface is faster than the mechano-chemical reaction rate in Second Region and the synergistic effect by stress and corrosion becomes slow. In case the fatigue load is large, we have the critical crack growth rate which is not related to the cyclic stress intensity. 6. The corrosion crack growth rate by the mechano-chemical reaction is the same in $H_{2}$S $O_{4}$ solution and salt water, so Hydrogen accelerates the crack growth. 7. The environment has no effect on the corrosion fatigue crack growth rate in Third Region. 8. In First Region and Second Region, dimple is observed on the fatigue fracture surface in 0.1N $H_{2}$S $O_{4}$ solution. 9. The striation is observed in any environment as in air in Third Region and its interval approximately coincide with the crack growth rate.ate.e.e.

• Proceedings of the KSME Conference
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• 2000.11a
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• pp.268-273
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• 2000

Mechanical properties of the materials used for transportations and industrial machinery under high strain rate loading conditions are required to provide appropriate safety assessment to these mechanical structures. The Split Hopkinson Pressure Bar(SHPB) technique, a special experimental apparatus, can be used to obtain the material behavior under high strain rate loading condition. In this paper, dynamic deformation behaviors of the aluminum alloys, Al2024-T4, Al6061-T6 and Al7075-T6, under high strain rate compressive and tensile loading are determined using SHPB technique.