• Journal of the Korean Society of Industry Convergence
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• v.25 no.4_2
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• pp.565-572
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• 2022

The white plume from the cooling tower can be generated by mixing between discharging hot and humid air and cold air outside. This causes various problems such as icing, traffic disturbances, and fire factors in the vicinity, moreover it can also damage the image of a company. Various methods can be used to prevent white plume, one of them is to install a heat exchanger at the outlet of the cooling tower so that the heat exchanger transfers as much heat as possible to lower the temperature. Therefore the air flow path in the cooling tower should be optimized. Installation of the filler can be used to make the air flow better, thus we investigate the effect of filler on the air flow using CFD method. The pressure and velocity profile in the cooling tower could be acquired by the calculations. The filler made the velocity of the air entering the heat exchanger uniform this was because high flow resistance of the filler suppresses the generation of eddy in the cooling tower. But the total air pressure drop increased about 2 times with filler because the pressure drop by the filler accounted for about 60% of the total pressure drop.

• Journal of Korea Multimedia Society
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• v.18 no.2
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• pp.189-198
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• 2015

Despite the fact that traffic engineering techniques have been comprehensively utilized in the past to enhance the performance of communication networks, the distinctive characteristics of Software Defined Networking (SDN) demand new traffic engineering techniques for better traffic control and management. Considering the behavior of traffic, large flows normally carry out transfers of large blocks of data and are naturally packet latency insensitive. However, small flows are often latency-sensitive. Without intelligent traffic engineering, these small flows may be blocked in the same queue behind megabytes of file transfer traffic. So it is very important to identify large flows for different applications. In the scope of this paper, we present an approach to detect large flows in real-time without even a short delay. After the detection of large flows, the next problem is how to control these large flows effectively and prevent network jam. In order to address this issue, we propose an approach in which when the controller is enabled, the large flow is mitigated the moment it hits the predefined threshold value in the control application. This real-time detection, marking, and controlling of large flows will assure an optimize usage of an overall network.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.30 no.4
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• pp.1-8
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• 2022

In this study, we propose trajectory-based arrival management using CDO (Continuos Descent Operations). The operational procedures with TBO (Trajectory-Based Operations) concept were established to allow aircraft and ground system to share the trajectories with each other in real time. The proposed operational concept was validated in the air traffic control simulation environment, which consists of controller working position, pseudo pilot system, air traffic generation system, and controllers' decision support system for arrival management using CDO. Simulation results compared with actual flight data indicate that proposed concept could improve the efficiency of traffic flow management in terms of total descending time and fuel consumption. And it was confirmed that if there is a system that can share and utilize the synchronized trajectory, it can be helpful to control arrival aircraft and apply CDO concept.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.22 no.4
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• pp.42-55
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• 2014

The purpose of this research was to identify expertise in ait traffic control by using cognitive skill analysis for novices and experts in routine and non-routine situations. The result of study was to understand expertise in air traffic control tasks in terms of what cognitive processes are responsible for the expert's high performance levels. The problem solving task was difficult for novices, but performed relatively automatically by experts in a routine situation. The difficulty could indicate the presence of controlled processing. Rather than rules and strategies, novices focused more on environmental factors, which merely increase cognitive load. In a non-routine situation, novices showed that they did not categorize the information consistently and alternative resources were not available for them. Experts, however, performed automatically a task by arranging and organizing information related to problem solving components in contexts without regard to a routine and non-routine situation. Especially experts developed a stable representation and directed alternative resources for air traffic flow and efficiency. Based on the results, cognitive processes of experts could be useful to understand expert performance and analyze the learning process, which imply the necessity of developing expertise systematically.

• 한국항공운항학회:학술대회논문집
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• 2006.05a
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• pp.25-31
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• 2006

• Asian Journal of Turfgrass Science
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• v.21 no.2
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• pp.127-135
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• 2007

Korea and Japan hosted the FIFA World Cup Soccer Game in 2002. Ten stadiums had been built and more than 30 soccer grounds for practice were renovated in Korea. Sport fields in both countries had problems on cool-season turfgrass growth and quality by summer decline during humid and warm climate especially followed by intensive uses. We measured the effects of air-flow system, which is designed to optimize rootzone soil gas and moisture levels to promote the growth and maintenance turfgrass. This experiment was carried out to verify the effects of the system on soil gas exchange, ground resilience, and turfgrass recovery in turfgrass rootzone. Within 1 or 2hr of operation of the system, rootzone soil gas ($CO_2$, $O_2$) levels returned to natural atmospheric levels completely Soil $CO_2$ levels began to decrease within the first 10 min of operation of the system. The levels were reduced from 1.3 to 0.06% after 30 min, and natural atmospheric levels within 1 hr. When the system was turned off, $CO_2$ levels increased to 0.36% and 0.7% after 5 and 20 hr, respectively. The application of the system did not affect the resilience of turf surface after traffic treatments. Higher traffic treatment resulted in higher surface resilience especially in zoysiagrass plots. Operation of the system had a significant beneficial impact on turf recovery by increased root dry wight and improved turf quality, as compared with the non-operated check plots.

• Journal of Advanced Navigation Technology
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• v.14 no.4
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• pp.489-494
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• 2010

According to the recent increase in air traffic more efficient air traffic control automation is required. Aeronautical traffic environment is different from the common traffic environment since it exist controller for control of aircraft And controller have to control jurisdiction hand-off by manual when aircraft move to the other sector. This paper proposes the automatic control jurisdiction hand-off algorithm for efficient air traffic flow management. It is sector distinction algorithm that aircraft move sector to the other sector it recognized sector and then give permission to authorized controller. As a simulation result, so unlilke simply manual control sector hand-off of existing algorithm. we confirmed that proposed algorithm in this paper can do air traffic control more efficiently by performing automatic aircraft. control sector hand-off.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.1197-1198
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• 2008

The purpose of the Air Traffic Control(ATC) system is to provide a safe, efficient flow of air traffic from origin to destination. Therefor, it is important to reduce the operational errors. Most of errors occurs from controllers. So, we suggest the human machine interface scheme for Air Traffic Control system.

• Proceedings of the Turfgrass Society of Korea Conference
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• 2002.02a
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• pp.22-25
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• 2002

• Journal of the Korean Regional Science Association
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• v.15 no.2
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• pp.39-73
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• 1999

An examination is made of container movements, air cargo/passengers and telecommunications traffic in Northeast Asia during 1995. A drawback to studying flows between major cities is that information on telecommunications traffic is only available between countries. Also container traffic data are restricted to individual ports. Consequently, most attention is paid to movements of passenger aircraft between major cities derived from analysing timetables, particularly as they can be related to regional development concepts applied in Europe such as the 'blue banana' and 'bunches of grapes' concepts. A 'peas in a pod' may be a more appropriate movements are examined again in 1998 to gauge the impact of the Asian crisis.