• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2023.05a
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• pp.61-62
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• 2023

There have been cases where the number of port workers has temporarily decreased due to COVID-19. To prevent the spread of COVID-19, a number of workers were quarantined, resulting in bottlenecks and waiting throughout the port operation process, increasing the congestion of terminals. As a result, problems such as a decrease in terminal operation efficiency occurred. However, it is understood that congestion centered on unloading equipment inside the terminal is not clearly calculated. Terminal congestion is thought to be a key factor directly related to the operational efficiency of the terminal. The congestion calculation method generally used in various fields measures congestion based on image-based data. Due to the nature of the loading and unloading equipment that moves according to the quantitative loading plan, it is unreasonable to apply the existing congestion calculation method. Therefore, this study presented a method of calculating terminal congestion using equipment waiting time and turnaround time, and verified the statistical significance of the congestion calculated using data from Terminal A of Busan Port.

• Journal of Korean Port Research
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• v.14 no.1
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• pp.27-35
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• 2000

In Pusan Harbour, new port development projects are implemented such as the Extended Terminal adjacent to the Gamman Terminal, Pusan New Port, the Navy $\bigcirc$$\bigcirc$ piers, etc. which will require new marine traffic environments in the Passage I of Pusan Harbour. Specially, the turning basin of the Extended Terminal adjacent to the Gamman Terminal has been designed to overlay the Passage I of Pusan Harbour, which will interrupt the inbound traffic flow and the results will be worried to decrease the efficiency of port operation. Therefore, this paper will be aimed to evaluate the traffic congestion in the Pusan Passage I due to the opening of new ports within Pusan Harbour in 2006 and 2011 by using computer simulation based the queueing theory.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 1999.10a
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• pp.91-99
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• 1999

In Pusan Harbour, new port development projects are implemented such as the Extended Terminal adjacent to the Gamman Terminal, Pusan New Port, the Nary $\infty$ piers, etc. which will require new marine traffic environments in the Passage I of Pusan Harbour Specially, the turning basin of the Extended Terminal adjacent to the Gamman Terminal gas been designed to overlay the Passage I of Pusan Harbour, Which will interrupt the inbound traffic flow and the results will be worried to decrease the efficiency of port operation. Therefore, this paper will be aimed to evaluate the traffic congestion in the Pusan Passage I due to the opening of new ports within Pusan Harbour in 2006 and 2011 by using computer simulation based the queueing theory.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2018.05a
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• pp.57-58
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• 2018

As interest in the Internet of Things increases, technologies are being studied to handle information exchanged between things using the Internet of Things. Specially, as container terminals are automated, the use of the Internet of Things in the terminals increases and varies. However, the use of the Internet of Things to enhance the efficiency of the container terminal operation is insufficient. Currently, the container terminal shows that the arrival pattern of the external truck is concentrated at a particular time. This resuls in gate congestion and affects the waiting times of the truck. The damage is caused by environmental pollution problems and social problems in neighboring port areas. Therefore, in this thesis, we will analyze the causes of the external truck's waiting time problems affecting the gate congestion at container terminals and study methods to mitigate congestion under Internet of Things environment.

• Journal of Navigation and Port Research
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• v.45 no.6
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• pp.314-324
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• 2021

Competition between ports around the world is intensifying to attract transshipment cargo. However, recently, there have been concerns about the departure of transshipment cargo volume at Busan Port, such as the lifting of the cabotage policy in China's shipping sector and the implementation of a safe fare system. In terms of operation, terminal congestion and vehicle waiting time are seriously occurring due to imbalance in the transshipment volume of each terminal and vehicles concentrated in a specific time period. In this paper, we propose a method of inter-terminal transportation (ITT) using buffer space to solve the problem caused by inefficient ITT systems and presented a mixed integer programming (MIP) for the problem. The effect of using the buffer space was analyzed for various work volumes and capacity fluctuation ranges by applying the terminal congestion pattern and ITT vehicle in/out pattern based on the Busan New Port data.

• Journal of Navigation and Port Research
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• v.46 no.4
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• pp.344-350
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• 2022

Due to the increase in container cargo volume, the congestion of container terminals is increasing and the waiting time of gate in-out trucks has significantly lengthened at container yards and gates, resulting in severe inefficiency in gate in-out truck operations as well as port operations. To resolve this problem, the Busan Port Authority and terminal operator provide services such VBS, terminal congestion information, and expected operation processing time information. However, the visible effect remains insufficient, as it may differ from actual waiting time.. Thus, as basic data to resolve this problem, this study presents deep learning based average gate in-out truck waiting time prediction models, using container gate in-out information at Busan New Port. As a result of verifying the predictive rate through comparison with the actual average waiting time, it was confirmed that the proposed predictive models showed high predictive rate.

• Journal of Information Processing Systems
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• v.2 no.1
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• pp.34-38
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• 2006

In the wireless network, TCP performs poorly because it was originally designed for wired networks and does not take into consideration wireless characteristics such as mobility, high-loss probability, and hidden-terminal problems. In particular, in the wireless multi-hop networks, a large congestion window increases the probability of contention and packet losses, and TCP performance is degraded severely as a result. So, it is necessary to limit the TCP congestion window size in order keep the probability of contention loss in the system to a minimum. In this paper, we propose a new scheme for determining the maximum congestion window size based on the measured bandwidth and Round-Trip-Time (RTT). Using ns-2 simulation, we show that the proposed scheme reduces the probability of packet contention and improves TCP performance.

• Journal of Navigation and Port Research
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• v.46 no.3
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• pp.236-242
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• 2022

Busan Port is operated separately by a number of terminal operators, resulting in a large number of ITT (Inter-Terminal Transportation) volumes. The occurrence of ITT volume causes various problems such as additional transportation cost, empty truck trips, truck delays and terminal congestion, weakening Busan Port's competitiveness. Among them, the empty truck trip problem is a representative factor, that exacerbates the cost problem of the ITT operation at Busan Port. But the ITT backhaul rate at Busan Port remains low. To strengthen the transhipment competitiveness of Busan Port, it is necessary to increase the ITT backhaul rate. In this paper, to improve ITT backhaul rate, we present a mathematical model for maximizing backhaul transport using buffer space. And we analyzed the improving effects of backhaul transport using buffer space through experiments based on actual operating data.

• International Journal of Internet, Broadcasting and Communication
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• v.15 no.1
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• pp.1-7
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• 2023

TCP is considered a major candidate transport protocol even for constrained IoT networks due to its ability to integrate into the existing network infrastructures. Since TCP implementations such as uIP TCP often allow only a single TCP segment per connection to be unacknowledged at any given time due to resource constraints, the congestion control relies only on RTO management. In our previous work, to address the problem that uIP TCP performs poorly particularly when a radio duty cycling mechanism is enabled and the hidden terminal problem is severe, we proposed a RTO scheme for uIP TCP and validated the performance through Cooja simulation. In this study, we investigate the effect of other factors that were not considered in our previous work. More specifically, the effect of traffic intensity, the degree of the hidden terminal problem, and RDC is investigated by varying the offered load and the transmission range, and the RDC channel check rate. Simulation results imply that we need to further investigate how to improve TCP performance when the radio duty cycling mechanism is used.

• Korean Journal of Veterinary Research
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• v.18 no.1
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• pp.9-13
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• 1978

Nitrate poisoning was observed in Holstein calves raising for beef purpose in a dairy-farm of Gyeongbug province. The results observed were summarized as follows: 1. These calves had been fed mainly cornstalk, and a qualitative reaction by "dephenylamine blue test" for nitrate was positive in the serum of the affected calves and in the cornstalk provided. 2. In the clinical signs, the affected calves were suddenly recumbent without premonition and then dyspnea, followed by death. Death also occurred after inappetence, depression, dyspnea, cyanosis of mucous membrane, and terminal anoxic convulsions were observed. 3. In the macroscopical findings, the blood was dark brown (chocolate in color) and more or less poor coagulative. Petechiae of epicardium, severe cloudy swelling of liver, cloudy swelling and hemorrhage of kidney, congestion and hemorrhage of spleen, congestion and edema of lung, and congestion af abomasum and small intestine were observed in these cases. 4. Microscopical changes observed in these cases were peripheral congestion of lobules, centrilobular necrosis and sinusoidal dilatation in liver, hydropic degeneration of hepatic cells, hemorrhage and edema of kidney, necrosis of convoluted-tubular epithelium, and dilatation of Bowman's space and convoluted tubule. There were also congestion and hemorrhage of spleen, hemorrhage and edema of lung, cloudy swelling of myocardium, and congestion and hemorrhage of various organs.