• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.17 no.9
• /
• pp.2219-2226
• /
• 2013

Optical phase conjugation combining with dispersion management (DM) is promising technique to compensate for signal distortion due to group velocity dispersion (GVD) and nonlinear Kerr effects in optical communication systems. However the fixed residual dispersion per span (RDPS) usually used in the optical links with OPC and DM restricts the flexible link configuration. In this paper, OPC links combining DM of the randomly distributed RDPS is proposed for implementing the flexible optical transmission network. It is confirmed that the excellent compensation in the optical links with the randomly distributed RDPS is obtained, limiting the launch power of WDM channels to the relatively low. It is also confirmed that the relatively high launch power WDM channels are effectively transmitted through the optical links with the randomly distributed RDPS of averaged 50 - 100 ps/nm.

• Journal of Korean Society of Environmental Engineers
• /
• v.27 no.4
• /
• pp.438-444
• /
• 2005

This study is to install the flexible vertical in order to separate not only the time but also the space in the single reactor by opening and closing the flexible vertical, and to intensify the aerobic, anaerobic and anoxic reactions by reducing the time to activate the microorganism for nitrification, denitrification, release of organic phosphate and luxury uptake of ortho-phosphate. Eventually the result of this study obtained each 90.9%, 76.4% for the removal efficiency of total nitrogen and phosphate. Also, content rate of phosphate at excess sludge was higher $25{\sim}30%$ for SBR reactor with the flexible verticals than existing SBR process. It would be concluded that SBR reactor with flexible verticals is promising for nitrogen and phosphate removal conditions than conventional SBR processes.

• Journal of Advanced Navigation Technology
• /
• v.17 no.4
• /
• pp.413-420
• /
• 2013

The design rule depending on total transmission length is induced in the optical links with residual dispersion per span (RDPS) of the random distribution, which is adopted for implementing the flexible systems of wavelength division multiplexing (WDM) transmission with dispersion management (DM) and optical phase conjugation. DM parameters used for the analysis of the design rule are the effective net residual dispersion (NRD) and the effective launch power. It is confirmed that the flexible optical network configuration with the total transmission length lower than 1,000 km is possible, because the system performance difference between the randomly distribution and the uniform distribution of RDPS is small. And, in the optical links with the randomly distributed RDPS, the wide NRD can be applied for transmitting WDM channels of the relatively wide launch power.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.16 no.10
• /
• pp.2293-2302
• /
• 2012

New optical transmission links technique for compensating of the distorted wavelength division multiplexed (WDM) signals due to group velocity dispersion (GVD) and self phase modulation (SPM) in single mode fiber (SMF) are proposed. The proposed optical links have optical phase conjugator (OPC) placed at nearby WDM transmitter or receiver and repeater spans with artificial distribution of SMF length and residual dispersion per span (RDPS). It is confirmed that optimal link configuration expanding effective launching power range and effective net residual dispersion (NRD) by improving system performance is that having OPC closely placed at WDM receiver and the gradually descended distribution of SMF length and RDPS of each repeater spans, related with the gradually increased optical link length. And, it is also confirmed that NRD is controlled by postcompensation in optimal optical link with OPC closely placed at WDM receiver.

• Journal of Digital Convergence
• /
• v.12 no.2
• /
• pp.89-97
• /
• 2014

With regard to conventional theory, the rate of profit is determined by the interaction between the rate of surplus value and the organic composition of capital. And it declines with the capitalistic development through intensifying the organic composition of capital. According to the empirical test, the rate of profit and the rate of surplus value have been decreased. On the contrary, the organic composition of capital have increased during the period under study. The empirical results of the rate of profit in Korean economy appears to hold the principle of the law of the tendency of the rate of profit to fall. But the trend of the determinants is distinct from the conventional theory. Despite the distinctive empirical results, the law of the tendency of the rate of profit to fall is realized in Korean economy in objective period of time.

• Environmental and Resource Economics Review
• /
• v.25 no.4
• /
• pp.517-543
• /
• 2016

This study aims to analyze economic impacts for changes in the oil cost of the anchovy boat seine fisheries in South Korea. As analytical approach, this study employs the exponential surplus production model to estimate the maximum sustainable yield and also utilizes the bioeconomic model to calculate changes in producer surplus of the anchovy boat seine fisheries under the open access responding to changes in the oil cost. As the result of analysis, increases in the oil cost due to prohibition of duty-free oil supply result in the negative impacts to the producer surplus of the anchovy boat seine fisheries in South Korea. However, increases in the oil cost of the anchovy boat seine fisheries lead voluntary exit to fishermen which can no more run their business. As a result, this study shows that fishing efforts of the anchovy boat seine fisheries reduce under the fishing efforts of the maximum sustainable yield ($F_{MSY}$) and stock of the anchovy increases.

• Journal of Energy Engineering
• /
• v.21 no.3
• /
• pp.301-308
• /
• 2012

This paper attempts to estimate the demand function for the transport LPG and to analyze long-run and short-run price and income elasticities. In addition, the paper measures consumer surplus and economic value ensuing from the transport LPG consumption by utilizing the estimated long-run price elasticity. The price and the income data are the monthly real transport LPG price and the monthly composite index adjusted by real transport LPG price from 2003 to 2012. Unit root test, co-integration test and error correction model are to take the procedure of estimation of demand curve. The demand for transport LPG is considered to be inelastic and the long-run demand is more elasticity than that of short-run. Price elasticity of demand estimate here is -0.422, and the estimated consumer surplus and economic value in 2010/03 are 966 and 1,781 billion won, respectively.

• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.27 no.2
• /
• pp.105-112
• /
• 2015

In this study, the erosional properties of deposit bed for the natural sediments are quantitatively estimated domestically for the first time using annular flume. Four erosion tests for Saemankeum sediments have been carried out on different consolidation time. Experimental results of erosional tests show that shear strength ${\tau}_s$ increases with the increases of consolidation time and bed depth. The erosion rate increases logarithmically with the increases of exceed shear strength ${\tau}_b-{\tau}_s$. But, the erosion rate decreases rapidly with the decreases of exceed shear strength under the $0.2N/m^2$. Experimental results of this study are found to be remarkably different in quantity as compared with those for results of previous study.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.34 no.10B
• /
• pp.1043-1049
• /
• 2009

Broadcast of sink node is used for network management, data collection by query and synchronization in wireless sensor networks. Simple flooding scheme induces the broadcast storm problem. The MPR based broadcast schemes reduce redundant retransmission of broadcast packets. MPR is a set of one hop neighbor nodes which have to relay broadcast message to cover all two hop neighbors. Though MPR can reduce redundant retransmission remarkably, it still suffers from energy waste problem caused by collision and duplicate packets reception. This paper proposes a new MPR based sink broadcast scheme using 3-channel. The proposed scheme reduces energy consumption by avoiding duplicate packet reception, while increases reliability by reducing collision probability remarkably. The results of analysis and simulation show that the proposed scheme is more efficient in energy consumption compared to the MPR based scheme. The result also shows that the proposed scheme reduces delivery latency by evading a contention with other relay nodes and improves reliability of broadcast message delivery by reducing collision probability.

• Journal of the Korean Data and Information Science Society
• /
• v.24 no.1
• /
• pp.1-12
• /
• 2013

In this paper, we introduce a continuous-time risk model where the surplus follows a diffusion process with positive drift while being subject to two types of claims. We assume that the sizes of both types of claims are exponentially distributed and that type I claims occur more frequently, however, their sizes are smaller than type II claims. We obtain the ruin probability that the level of the surplus becomes negative, by establishing an integro-differential equation for the ruin probability. We also obtain the ruin probabilities caused by each type of claim and the probability that the level of the surplus becomes negative naturally due to the diffusion process. Finally, we illustrate a numerical example to compare the impacts of two types of claim on the ruin probability of the surplus with that of the diffusion process in the risk model.