• Journal of the Korean Society for Aviation and Aeronautics
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• v.21 no.2
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• pp.26-32
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• 2013

The rotorcraft makes lift and control forces by the rotor thrust. At the development phase of the rotorcraft, the operational limitations have to be established. And it shall be demonstrated to operate the rotorcraft safely within the limitations. This paper introduces establishment and evaluation results of operational rotor speed limitations for the medium class utility rotorcraft. And it shows the follow-up activities after design changes of rotor speed indicators and aural warning systems for implementing the rotor speed limitations.

• The Journal of Korea Robotics Society
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• v.13 no.3
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• pp.182-189
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• 2018

The purpose of this paper is to suggest the methodology for the establishment of operational concept for speed-up of defense robot and improvement direction of the defense acquisition system for the defense robot. In order to achieve this goal, the current defense acquisition system was analyzed into long-term planning, mid-term programming, and project execution stages. And I suggest the methodology for the establishment of operational concept for speed-up of defense robot and direction of development of the defense robot acquisition system considering the characteristics of the robot in terms of core technologies of robot, robot ecosystem and effectiveness-based-robot-design, respectively. Based on the methodology for establishment of the operational concept of defense robot and development direction of the defense acquisition system presented in this study, it will be possible to design efficiently the defense robot in the future.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.9
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• pp.1715-1720
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• 2011

Studies suggested an increase in the competitiveness and roles of mainline railways like speed and accessibility improvement, as a fundamental direction of the National Transport Network Plan. At this point, topics presented especially for strengthening the role of human and environment centered transportation: as to the greatly improved speed competitiveness, there are an operational speed above 180km/h ~ 200km/h and traveling within 2 ~ 3 hours among big cities. As to accessibility improvement, there are accessibility to main railway stations within 30 minutes, and the improvement of accessibility, safety, eco-friendliness, amenity etc. As a part of these suggestions, field specific plans were proposed for the establishment of expressed mainline railway network in Korea such as train's, civil structures, trolley lines etc. In this paper we analyzed the conventional lines and systems to figure out whether to change details in terms of H/W of signaling system. Additionally, we reviewed the compatibility or difference of signalling system depending on train's speed. With this result, we deduced the number of virtual blocks specific to the speed of 180km/h, 200km/h and 230km/h, which were showed for the speed improvement considering each variable like blocks, braking distance etc. In this way, we suggested the railway signal system establishment plan considering safety operation.

• Proceedings of the KSR Conference
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• 2007.11a
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• pp.377-385
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• 2007

The importance of maintenance of rail surface defects is increasing more according to the KTX operation. That is because during high speed operation of rolling stock, rail surface defects may cause shortened fatigue life of rail, acceleration of track degradation and reduced ride comfort. The paper was intended to study the establishment of rail grinding criteria of high-speed railway lines considering the KTX operation circumstances. For this, the specimens of UIC 60 rail on Kyeong-Bu high-speed operation lines were collected and they were analyzed for metallographic structure and tested for the hardness. By analyzing the test results to the factors affecting the RCF causing the defects of rail surface, the study suggested the rail grinding criteria of the domestic high speed railway lines. As the factors affecting RCF, passing tonnage, running speed and track condition are considered.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.18 no.3
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• pp.23-38
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• 2015

The study was initiated with Kentucky bluegrass (KB, Poa pratensis L.) to investigate germination and early establishment characteristics of new cultivars for a practical application to turfgrass establishment such as parks, athletic field and golf course etc. Fifteen cultivars were evaluated in different experiments. An alternative condition for a KB germination test required by International Seed Testing Association (ISTA) was applied in Experiment I, consisting of 8-hr light at $25^{\circ}C$ and 16-hr dark at $15^{\circ}C$ (ISTA conditions). Experiment II was conducted under a room temperature condition of 5 to $25^{\circ}C$ (natural conditions). Seed germinating vigor, germination speed and germination peak time were measured in both experiments. Significant differences were observed in seed germinating vigor, germination speed and germination peak time. Seed germinating vigor was variable with different environments and cultivars. It was 75.25 to 89.50% under ISTA conditions and 75.75 to 90.25% under natural conditions. There were considerable variations in early germination characteristics among KB cultivars according to different environments. Early germination characteristics showed that all cultivars were 3 to 5 days faster in germination under ISTA conditions, when compared with natural conditions. The germination speed, measured as days to seed germination of 50% to 80%, was much faster with 'Midnight II', 'Excursion' and 'Midnight' under ISTA conditions. But it was faster with 'Midnight II', 'Excursion' and 'Odyssey' under natural conditions. Differences was also observed in germination peak time with cultivars and growing conditions. It ranged 5.94 to 14.88 days under ISTA conditions and 4.71 to 13.06 days under natural conditions. Regardless of the environment conditions, the shortest cultivars were 'Odyssey' and 'Midnight II'. The longest ones were 'Nuglade' under ISTA condition and 'Moonlight' under natural conditions. Considering germinating vigor, germination speed and germination peak time, 'Midnight II', 'Excursion', 'Midnight', and 'Odyssey' were regarded as excellent cultivars under ISTA conditions in terms of early establishment characteristics, while 'Midnight II', 'Excursion', 'Odyssey', and 'Courtyard' under natural conditions. These results suggest that an intensive germination test be needed prior to planting, for investigating the early germinating vigor, germination speed and germination peak time. Also, a proper cultivar selection and comprehensive site analysis for the growing environmental conditions should be done before turfgrass establishment such as golf course construction.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.1
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• pp.23-29
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• 2006

From a point of view of suggesting the method to avoid ship's collision, the speed of ships has to be considered sufficiently according to encounter angle of ships. But with respect to the establishment of Safe-Guard Ring of Ship Collision Avoidance Support Model in Close Quarters Situation that had been newly studied to avoid ship's collision, the ratio of own ship' speed to a target ship's speed was limited to about less than 1.7. Therefore in this paper, as doing a study concerned with the establishment of Safe-Guard Ring reflected the encounter angle and the speed of ships, we will propose the new model of ship collision avoidance for safe maneuver of ship's collision avoidance.

• Proceedings of the KSR Conference
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• 2009.05b
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• pp.517-524
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• 2009

This paper proposes a magnetic analysis model and design method of transformer for the high-speed EMU. It has a many part of the consideration in design because the transformer in high-speed train has the multiple output. Also the output characteristic, weight, and size of transformer is an important factor. This research proposes a design method of transformer in high-speed EMU. And it is easy to design by using the analysis model in design the transformer through the establishment of the magnetic analysis model.

• Weed & Turfgrass Science
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• v.6 no.4
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• pp.313-321
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• 2017

Wetting agent is designed to reduce the surface tension of the liquid and spread more easily across or penetrate into the soil against water repellency. The effect of wetting agent to seed germination is not clear. Using germination enhancer is one of the methods to increase the germination speed of turfgrass seeds and to shorten establishment period. The objective of the study was to evaluate germination enhancer and wetting agent for quick establishment of various Kentucky bluegrass cultivars. The germination enhancer was used at two levels of 0.3 and $0.6ml\;kg^{-1}$ as low and high, respectively. Two levels of wetting agent were of 0.46, and $0.92ml\;m^{-2}$ as low and high, respectively. Germination enhancer has no synergistic effect with wetting agent. When quick establishment is required, selection of cultivar would be more effective instead of using germination enhancer and wetting agent. Among Kentucky bluegrass cultivars, 'Award' had the greatest turfgrass coverage for establishment and the greatest turfgrass color and quality based on the result of the study. When quick establishment is required, selection of cultivar would be more effective instead of using germination enhancer and wetting agent.

• Proceedings of the KSR Conference
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• 2002.10a
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• pp.357-366
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• 2002

In this paper the cases on accidents/incidents and the reporting/responding procedures of high-speed rail operating countries will be reviewed and what these suggest us will be identified, and those countries' efforts to secure the prompt rescue system will be reviewed and the plan to secure the more customized rescue and rehabilitation system taking account into circumstances of our high-speed railway accident/incident will be presented.

• Proceedings of the KIEE Conference
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• summer
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• pp.1425-1428
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• 2004

Internal traffic system becomes fast with high-speed railway. Therefore, skill development for speed elevation is consisting in general railroad. New skill that is car report lake system is examined in railroad signal field. Therefore, examined establishment way and problem of car report lake system equipment. Examine equipment performance and studied method of most suitable that use.