• Journal of Korea Water Resources Association
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• v.53 no.spc1
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• pp.719-730
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• 2020

Recognizing a complexity of global water challenges, such as water shortage, water pollution, water-related disasters, and degradation of water environments, this study introduces the newly established concept and definition of water security and water security assessment framework based on the review of previous works on water security. In order to critically assess the situations of water security of each country, an water security assessment framework is employed highlighting the four core areas: 1) social equity; 2) economic efficiency; 3) environmental sustainability; and 4) resilience to water-related disasters. 28 Asian countries have been selected and evaluated for the level of water security, and as a consequence, Japan, Malaysia and South Korea demonstrate a high degree of water security whereas India, Pakistan and the Philippines show a relatively low level of water security. The significance of this study lies in clarifying weak areas in water security as well as suggesting the areas that should be improved for achieving sustainable water management.

• Journal of the Korea Organic Resources Recycling Association
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• v.9 no.3
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• pp.70-76
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• 2001

Proper design and improvement of the biofiltration process depend upon quantitative understanding of the kinetic behavior in the biofilter. This study was conducted to evaluate kinetics of biofiltration of gasoline vapor. Filling material of the biofilter was compost. Gas inlet concentration ranged from about $300mg/m^3$ to $7,000mg/m^3$. Gas velocities were 6m/hr and 15m/hr, respectively. At 6m/hr gas velocity, about 60% of gasoline TPH below $3,000mg/m^3$ was removed in the lower quarter part of the biofilter. First order kinetics described well the degradation rate of gasoline TPH with high correlation. First order kinetic removal constant at the gas velocity of 6m/hr was higher than that of 15m/hr from about $300mg/m^3$ to $7,000mg/m^3$. When the inlet concentration was over $3,000mg/m^3$, first order kinetic removal constant at the gas velocity of 6m/hr was over twice that at 15m/hr. In order to obtain over 80% of removal efficiency, gasoline vapor should be injected into the biofilter at concentration below about $2,000mg/m^3$, 100cm filling height and the gas velocity of 6m/hr.

• Journal of the Korea Organic Resources Recycling Association
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• v.2 no.1
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• pp.31-40
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• 1994

In the later part of 1980's, a great emphasis has been placed on the treatment issues of livestock wastes due to the continuous increase in consumption of livestock and meat products. Continued economic development for three decades has enhanced the nationally general level of life for the purpose of exit out of absolute poverty, thus accompanied with people's demand for a quality of environment beyond the traditional economic factors over times. Such an individual or collective demand for environment of life has been primarily focussed and argued on only rural environment in the early development periods. In perspective of clean water supply and security for urban area, however, it is more important to treat livestock wastes in the oriented-sustainable environment than in the conventional ways without working on environment degradation. Livestock wastes composed of the high-concentrated organic matter ought to be controlled and treated in sound ways, if not, which on one hand may result in pollution of underground water, surface water and a nasty smell, and on the other hand also may cause people to file a civil petition. Therefore on the research paper, reviewing occurrence of livestock waste and situation of treatment in details, through scrutinizing the government regulation and financing or subsidizing for it, author intends to find out the initiative of 'resourcefication' of treating of livestock wastes in the environmental soundness and efficiency

• Smart Media Journal
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• v.3 no.1
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• pp.52-62
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• 2014

Prevalence of common three-dimensional display progresses, increasing the demand for three-dimensional content. Starting from the year 2010 to meet increasing 2D to 3D conversion is insufficient to meet demand content was presented as an alternative. But, Convert 2D to 3D stereo effect only emphasizes content production as a three-dimensional visual fatigue and the degradation of the Quality problems are pointed out. In this study, opened in 2011 'Scenes Guan', the 13 selected Scene is made of the three-dimensional transform the content and the Quality of the transformation applied to the Depth-Map is a visual representation of three-dimensional fatigue and, the adequacy of whether the expert has group interviews and surveys were conducted. Many of the changes are applied to the motion picture of the three-dimensional configurations of Depth-Map conversion technology used in many ways before and after the analysis of the relationship of cascade configurations to create a depth map to the stage. Experiments, presented in this study is a three-dimensional configuration of Depth-Map transformation can lower the production of a three-dimensional visual fatigue and improve the results obtained for a reasonable place was more than half of the experiment accepted the expert group to show a positive reaction were. The results of this study with a rapid movement to convert 2D images into 3D images of applying Depth-map configuration cascade manner to reduce the visual fatigue, to increase the efficiency, and has a three-dimensional perception is the result derived.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.39 no.1
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• pp.20-33
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• 2002

Usage of ATM AAL2 packets becomes dominant to increase transmission efficiency of voice traffic in the backbone network. In case of voice service that uses AAL2 mechanism, if resources of network are enough, connection of new call is accepted. However, due to packets generated by the new call, transmission delay of packets from old calls can increase sharply. To control this behavior, in this paper we present an AAL2 buffer management scheme that allocates a virtual buffer to each call and after calculating its propagation delay variation(PDV), decides to drop packets coming from each call according to the PDV value. We show that this packet dropping algorithm can effectively prevent abrupt QoS degradation of old calls. To do this, we analyze AAL2 packet composition process to find a critical factor in the process that influences the end-to-end delay behavior and model the process by K-policy M/D/1 queueing system and MIN(K, Tc)-policy M/D/1 queueing system. From the mathematical model, we derive the probability generating function of AAL2 packets in the buffer and mean waiting time of packets in the AAL2 buffer. Analytical results show that the AAL2 packet dropping algorithm can provide stable AAL2 packetization delay and ATM cell generation time even if the number of voice sources increases dramatically. Finally we compare the analytical result to simulation data obtained by using the COMNET Ⅲ package.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.37 no.9
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• pp.15-22
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• 2000

The effects of carrier transport and input power on the extinction ratio was theoretically analyzed in a 1.55${\mu}m$ InGaAsP/InGaAsP multiple-quantum-well(MQW) electroabsorption(EA) modulator. Poisson's equation, current continuity equations for electrons and holes, and optical field distribution were self-consistently solved by considering electric field dependent absorption coefficients. The field screening effect due to the carrier accumulation in heterointerface and the space-charge region occurred more seriously at the input side of modulator as input optical intensity increased. It was revealed that extinction ratio could be steeply degraded for modulator with the length of 200${\mu}m$ when an input power exceeds 10mW. A degradation of extinction ratio due to the field screening effect would be more significantly at high-performance devices such as a 1.55${\mu}m$DFB-LD/EA-modulator integrated source where optical coupling efficiency is almost complete or a very high-speed modulator with its length as short as a few tens ${\mu}m$.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.43 no.4 s.310
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• pp.74-86
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• 2006

This paper proposes a robust and computationally efficient algorithm for automatic video object segmentation. For implementing the spatio-temporal segmentation, which aims for efficient combination of the motion segmentation and the color segmentation, an SOM-based hierarchical clustering method in which the segmentation process is regarded as clustering of feature vectors is employed. As results, problems of high computational complexity which required for obtaining exact segmentation results in conventional video object segmentation methods, and the performance degradation due to noise are significantly reduced. A measure of motion vector reliability which employs MRF-based MAP estimation scheme has been introduced to minimize the influence from the motion estimation error. In addition, a noise elimination scheme based on the motion reliability histogram and a clustering validity index for automatically identifying the number of objects in the scene have been applied. A cross projection method for effective object tracking and a dynamic memory to maintain temporal coherency have been introduced as well. A set of experiments has been conducted over several video sequences to evaluate the proposed algorithm, and the efficiency in terms of computational complexity, robustness from noise, and higher segmentation accuracy of the proposed algorithm have been proved.

• Journal of the Institute of Electronics and Information Engineers
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• v.54 no.2
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• pp.28-37
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• 2017

Multipath TCP (MPTCP), which is a layer 4 protocol that can get the reliability and the efficiency of the transmission by using multipath transfer, was standardized by the IETF. MPTCP provides superior performance when compared to a single TCP when used in a homogeneous network with similar network characteristics. However, MPTCP degrades performance when used in heterogeneous networks with different network characteristics. In this paper, we propose 'Delay-alerted path-blocking scheduler'. It measures the delay of each path and blocks the path with a long delay to reduce the order of packets in the receive buffer. If the duplicated packet is sent to the blocked path to measure the delay and the congestion on the blocking path is reduced, the blocked path is unblocked. For performance analysis, the proposed scheduler was implemented in the Linux kernel and improved performance was obtained in the test bed. We also confirmed that the proposed scheduler reduces the degradation of MPTCP performance in real wireless networks with heterogeneous path characteristics.

• Korean Journal of Agricultural Science
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• v.22 no.1
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• pp.42-48
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• 1995

With the aim to investigation of decay resistance and optimum concentration in chrome-copper-arsenic(CCA) preservative treatment on the imported softwoods from Siberia and North america, preservative absorption after CCA impregnation, weight losses and degradation patterns by decay fungi were examined. The density and latewood rate of Siberia softwoods(Spruce and Larch) were higher than those of North america softwoods(Douglas-fir and Western hemlock), resulting in the decrease of the CCA preservative absorption in the Siberia softwoods. In the case of untreated softwoods, decay resistance against Coriolus versicolor was lower than against Tyromyces palustris. For CCA treated softwoods, preservative effectiveness increased with increase in concentration of CCA solution. When treated with 0.7% CCA solution, efficiency value was more than 80 and 90 for C. versicolor and T. palustris, respectively. From this results, in the CCA preservative treatment for imported softwoods, it can be concluded that optimum concentration of CCA solution is approximately 0.7%. The absorption of CCA preservative distributed in the range of 3.8 and $5.5kg/m^3$. After exposure to testing fungi, in the untreated softwoods, bore holes formed in the cell walls and bordered pits, moreover, bordered pit canals enlarged by the fungi. However, 0.5% CCA treated softwoods was almost no deterioration in the cell walls and bordered pits due to decay.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.6C
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• pp.544-561
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• 2002

In this paper, we propose a new hybrid type of the routing protocol (Virtual Cluster-based Routing Protocol: VCRP) for mobile ad-hoc networks, based on a virtual cluster, which is defined as a narrow-sense network to exchange the basic information related to the routing among the adjacent nodes. This particular approach combines advantage of proactive routing protocol (PRP), which immediately provides the route collecting the network-wide topological and metric information, with that of reactive routing protocol, which relies on the route query packet to collect the route information on its way to the destination without exchanging any information between nodes. Furthermore, it also provides the back-up route as a byproduct, along with the optimal route, which leads to the VCBRP (Virtual Cluster-based Routing Protocol with Backup Route) establishing the alternative route immediately after a network topology is changed due to degradation of link quality and terminal mobility, Our simulation studies have shown that the proposed routing protocols are robust against dynamics of network topology while improving the performances of packet transfer delay, link failure ratio, and throughput over those of the existing routing protocols without much compromising the control overhead efficiency.