• Korean Journal of Agricultural Science
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• v.43 no.3
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• pp.481-495
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• 2016

Lily, which is one of Korea's main flower exports, is one of the most important agricultural product in the country. Korean lily farmers have difficulty earning more profit from producing lilies, because of the high cost of lily bulbs. Most lily bulbs used in Korea are imported from the Netherlands. Thus, the Korean government has kept trying to supply more and better Korean lily bulbs. However, many experts have questioned the efficiency and economic value of the Korean lily production system. The purpose of this paper is to analyze the economic value of the production of lily bulbs in Korea. Especially, this study evaluates the economic value of the production systems of Korean lily bulbs and compares the results from several cases. The results of the present study presents some useful findings, as follows: first, two Korean production areas (Gangneung and Jeju) show a positive economic value but one Korean production area (Taean) presents problems causing a negative economic value. Second, the Korean production area in Vietnam currently has trouble in the view of economic value but will likely overcome that problem. Third, the production area in the Netherlands shows the best economic value. Thus, Korean lily bulb producers need to benchmark that system.

• Journal of Digital Contents Society
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• v.18 no.5
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• pp.943-948
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• 2017

Currently, embedded systems designed for specific applications are used extensively in consumer electronics, smart phones, autonomous vehicles, robots, and plant control, etc. In addition, the importance of DRAM, which has a great influence on the performance of an embedded processor constituting an embedded system, has been increasing day by day, and research on DRAM has been actively conducted in industry and academia. Therefore, it is important to have a more accurate DRAM model in order to obtain reliable results when evaluating the performance of an embedded processor through simulation. In this paper, we developed an embedded processor simulator capable of interworking with a DRAM simulator. We also analyzed the influence of the DRAM model, which operates correctly on a cycle-by-cycle basis, on the performance of the embedded processor by using the MiBench embedded benchmark.

• ETRI Journal
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• v.38 no.5
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• pp.847-857
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• 2016

Broadcasting services such as multi/single channel HDTV and 3DTV/2DTV use a multi-channel encoder that changes the bitrate and composition of the video service depending on the time. However, this type of multi-channel encoder could cause a longer latency owing to the variable bitrate and relatively bigger size of the buffers, which results in the same delay as in 3DTV even for a conventional DTV service. On the other hand, systems built based on separate encoders, each of which is optimized for the target service, might not have such latency problems. Nevertheless, there might be a distortion problem in the image and sound at the time of a switchover between two encoders with different output bitrates and group of picture structures. This paper proposes a system that can realize a seamless video service conversion using two different video encoders optimized for each video service. An overall functional description of the video service change control server, which is a main control block for the proposed system, is also provided. The experiment results confirm the seamless switchover and reduced broadcasting latency of DTV services compared with a broadcasting system composed of a multi-channel encoder system.

• Journal of Ginseng Research
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• v.32 no.2
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• pp.89-98
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• 2008

There are increasing evidences in the literatures on the potential role of ginsenosides in treating cardiovascular diseases. In this article, current information about ginsenosides-mediated vascular relaxation are reviewed. From the published studies using isolated organs, cell culture systems and animal models, ginsenosides are shown to relax blood vessels and improve blood flow through diverse mechanisms, including nitric oxide release by activating eNOS phosphorylation via PI3K/Akt and/or ERK1/2 pathways in endothelial cells, induction of inducible nitric oxide synthase through activation of NF-${\kappa}$B, reducing the intracelluar Ca$^{2+}$ levels by activating Ca$^{2+}$-activated K$^{+}$ channels in vascular smooth muscle cells and reducing platelet aggregation by decreasing thromboxane A$_2$ formation and intracelluar Ca$^{2+}$in platelets. In addition, the relevant clinical trials regarding the effects of ginsenosides on the cardiovascular disease are summarized, particulary focusing on managing hypertension and improving thrombotic disorders. Finally, antagonistic effects of ginsenosides on the prostaglandin H$_2$ receptor and scavenging effects on the generation of oxygen-derived free radicals in spontaneously hypertensive rats (SHR) are discussed.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.38 no.1
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• pp.44-51
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• 2015

When manufacturing die casting mold, generally, the casting layout design should be considered based on the relations of injection system, casting condition, gate system, and cooling system. According to the various relations of the conditions, the location of product defects was differentiated. High-qualified products can be manufactured as those defects are controlled by the proper modifications of die casting mold with keeping the same conditions. In this research, Computer Aided Engineering (CAE) simulation was performed with the several layout designs in order to optimize the casting layout design of an automotive part (Housing). In order to apply them into the production die-casting mold, the simulation results were analyzed and compared carefully. With the filling process, internal porosities caused by air entrapments were predicted and also compared with the modification of the gate system and overflow. With the solidification analysis, internal porosities occurring during the solidification process were predicted and also compared with the modified gate system. The simulation results were also applied into the production die-casting mold in order to compare the results and verify them with the real casting samples.

• Animal cells and systems
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• v.14 no.4
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• pp.291-296
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• 2010

Population ecological characteristics of growth and mortality play an important role in understanding the population dynamics of marine mammals. The instantaneous coefficients of natural and bycatch mortality were estimated for minke whales (Balaenoptera acutorostrata) in Korean waters using a population assessment model composed of bycatch and abundance data. The survivorship curve of this population was fitted to the data, and then the curve was revised using age-specific relative bycatchability coefficients ($q_t$). Instantaneous coefficients of natural and bycatch mortality of minke whales were estimated as 0.024/year and 0.076/year, respectively, and from this the survival rate was estimated as 0.905. This estimated survival rate was comparable to other cetaceans in other regions. The $q_t$ for this population ranged from 0.020 to 0.193. The revised survival rates were higher when the $q_t$ was taken into account. The mortality coefficient, survival rate, $q_t$ and survivorship curves had not previously been determined for minke whale in this area. This estimate could serve as fundamental information to assess the status of this population and for conservation and rational management.

• Journal of the Ergonomics Society of Korea
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• v.30 no.1
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• pp.29-39
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• 2011

Safety management paradigm which against human errors in aviation industry is now changing from the follow-up measures after accident in the past to systematic approach that a forecast the hazards and improve the working system of the group to prevent accidents. As human factors are based on the man's specific psychological traits, it takes much time and efforts to prepare the preventive measures. That's why aviation industry is interested in the accident-prevent measurements against human errors. In this thesis, therefore, we are going to introduce the efforts that aviation organizations have tried and recommend management systems and discuss the suggestive facts. At first, we discussed introduction of HFACS which is the systematic accidents-classification system related to human errors in the aviation organization and countermeasure in the aspects of management, technology/engineering, education training. We described about FOQA, LOSA, CRM/TEM, aviation safety information DB in the aspect of management, and explained safety technologies that prevent human errors or avoid technologically when emergency occurs in the aspect of technology/engineering. In the aspect of education training, we explained the application plan about safety programs(LOFT/Simulator use, CRM/TEM application etc).

• IEIE Transactions on Smart Processing and Computing
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• v.2 no.3
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• pp.148-159
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• 2013

An analysis of the throughput and stability region of random access systems is currently of interest in research and industry. This study evaluated the performance of a multiuser random access channel with a retransmission gain. The channel was composed of a media access control (MAC) determined by the transmission probabilities and a multiuser communication channel characterized by the packet reception probabilities as functions of the number of packet transmissions and the collision status. The analysis began with an illustrative two-user channel, and was extended to a general multiuser channel. For the two-user channel, a sufficient condition was derived, under which the maximum throughput was achieved with a control-free MAC. For the channel with retransmission gain, the maximum steady throughput was obtained in a closed form. The condition under which the random access channel can acquire retransmission gain was also obtained. The stability region of the general random access channel was derived. These results include those of the well-known orthogonal channel, collision channel and slotted Aloha channel with packet reception as a special instance. The analytical and numerical results showed that exploiting the retransmission gain can increase the throughput significantly and expand the stability region of the random access channel. The analytical results predicted the performance in the simulations quite well.

• Journal of the Earthquake Engineering Society of Korea
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• v.15 no.3
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• pp.45-55
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• 2011

In this study, the state of the art and characteristics of major Korean port structures were investigated and analyzed. Damage of port structures during earthquakes, evaluation systems of seismic damage and seismic designs have also been investigated. Based on the research, a methodology of seismic damage estimation was proposed considering geotechnical information and the characteristics of the fragility of port structures.

• Aerospace Engineering and Technology
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• v.12 no.1
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• pp.144-151
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• 2013

The KOrea Multi-Purpose SATellite-2 (KOMPSAT-2) is to provide 1.0 m Ground Sample Distance (GSD) panchromatic image and 4.0 m GSD multi-spectral image data for various applications. The KOMPSAT-2 system performs mission applications in the field of earth observations, covering land, sea, coastal zones, and Geographic Information Systems (GIS). The purpose of this document is to compute ground coordinate using satellite position, velocity and attitude data in KOMPSAT-2 and document for work-flow of location accuracy correction in KOMPSAT-2.