• Journal of the Korean Society of Safety
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• v.33 no.6
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• pp.1-7
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• 2018

The Continuous Ship Unloader (CSU) is an equipment that unloads freight from the ship docked in the port to the land. And the design target life time is designed to be 30 to 50 years, and it is classified as a semi-permanent large facility. However, cracks may occur due to structural defects, abnormal loads, and corrosion, and fatigue failure may occur before the design life is reached. In this study, we predicted the remaining life time of the main component of the CSU considering crack. And also proposed inspection cycle for maintenance of CSU based on the results of the remaining life time prediction. For this purpose, the structure, operational stresses of the CSU were analyzed and main members were selected. And tensile tests and fatigue crack propagation tests were performed with SM490YA and SM570TMC, which are used as main materials for CSU.

• The Journal of Korean Institute of Information Technology
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• v.17 no.9
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• pp.11-17
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• 2019

In recent years, damage and loss of life and property have been occurred frequently due to swelling waves in the East Sea. Swelling waves are not easy to predict because they are caused by various factors. In this research, we build a model for predicting the swelling waves occurrence in the East Coast of Korea using machine learning technique. We collect historical data of unloading interruption in the Pohang Port, and collect air pressure, wind speed, direction, water temperature data of the offshore Pohang Port. We select important variables for prediction, and test various machine learning prediction algorithms. As a result, tide level, water temperature, and air pressure were selected, and Random Forest model produced best performance. We confirm that Random Forest model shows best performance and it produces 88.86% of accuracy

• Journal of Korean Port Research
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• v.11 no.2
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• pp.273-280
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• 1997

Recently the importance of the cargo handling equipments in a port has been increasing to get strong competition from other ports. Many ports are making efforts to modernize their cargo handling equipments. The kernel technology of such equipments is the speed control of DC motor which is used as an essential part of them. In this paper, we discuss the speed control of a DC motor as a basic work for building cargo handling equipments in a port. DC Motors are still widely used in industrial fields, as driving power motor for electrical fields. DC drives, being easy to control, are widely used in many variable-speed and position control drive system. Traditional analog control circuits used in such applications have many disadvantages. Complex control schemes are difficult to implement with analog components. All these factor and invention of the microprocessor has made it possible to use digital control circuits, using microprocessing system. These digital circuits have been found to be reliable, flexible, and also immune to noise. In this paper it presents the speed control of a SCR DC motor driver which using dual converter by 80c196kc microprocessor. We developed a thyristor power amplifier which does not cause damage thyristor because it is designed to prevent triggering the two SCRs in the same arm simultaneously. And it was analyzed voltage and currents wave at reactive load.

• Journal of Hydrogen and New Energy
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• v.33 no.6
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• pp.827-837
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• 2022

If the hydrogen industry is activated, the introduction of C-type and pressurized liquefied hydrogen (LH2) tank suitable for small and medium-sized transp- ortation and storage will be given priority in the future. Therefore in this paper, the behavior for the LH2 property changes and boil-off gas (BOG) treatment of the C-type cargo tank through voyage of the LH2 carrier and pressurized tank of the LH2 receiving terminal were analyzed through computational simulations by making assumptions about the carrier operation and unloading conditions.

• Journal of Korean Port Research
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• v.1 no.1
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• pp.21-47
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• 1987

Nowaday all the countries of the world have studied the various problems caused in operating their own ports efficiently. Ship delay in the port is attributal to the inefficient operation in the navigation aids, the cargo handling, the storage and transfer facilities, and to the inefficient allocation of gangs or to a bad service for ships. Among these elements the allocation of gangs is the predominating factor in minimizing ship's turn round time. At present, in the case of Pusan Port. the labour union and stevedoring companies allocate gangs in every hatches of ships by a rule of thumb, just placing emphasis on minimizing ship's turn round time, without applying the principle of allocation during the cargo handling. Owing to this the efficiency of the cargo handling could not be expected to be maximized and this unsystematic operation result in supplying human resources of much unnecessary surplus gangs. Therefore in this paper the optimal size and allocation of gangs for minimizing the ship's turn round time is studied and formularized. For the determination of the priority for allocation the evaluation function, namely $F=PHi^{n}{\times}(W+H)$, can be obtained; where, PHI : Principal Hatch Index W : Total Cargo Weight represented in Gang-Shifts H : Total Number of Ship's hatches and also for the optimal size of gangs the average number of gang allocated per shift (Ng), namely Ng=W/PHI, is used. The proposed algorithm is applied to Pusan Port and its validity is verified.

• The Journal of Korea Robotics Society
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• v.19 no.1
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• pp.79-91
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• 2024

Large warehouses are building automation systems to increase efficiency. However, small warehouses, military bases, and local stores are unable to introduce automated logistics systems due to lack of space and budget, and are handling tasks manually, failing to improve efficiency. To solve this problem, this study designed small loading and unloading equipment that can be mounted on transportation vehicles. The equipment can be controlled remotely and is automatically controlled from the point where pallets loaded with cargo are visible using real-time video from an attached camera. Cargo recognition and control command generation for automatic control are achieved through a newly designed deep learning model. This model is designed to be optimized for loading and unloading equipment and mission environments based on the YOLOv3 structure. The trained model recognized 10 types of palettes with different shapes and colors with an average accuracy of 100% and estimated the state with an accuracy of 99.47%. In addition, control commands were created to insert forks into pallets without failure in 14 scenarios assuming actual loading and unloading situations.

• The Korean Journal of Air & Space Law and Policy
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• v.32 no.1
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• pp.177-200
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• 2017

This writer have thus far reviewed the civil and criminal obligations of the directors of a parent company that sponsored financially troubled affiliates. What was discussed here applies to logistics companies in the same manner. Hanjin Shipping cannot expect its parent company, Korean Air to prop it up financially. If such financial aid is offered without any collateral, under Korean criminal law, the directors of the parent company bears the burden of civil and criminal responsibility. One way to get around this is to secure fairness in terms of the process and the content of aid. Fairness in terms of process refers to the board of directors making public all information and approving such aid. Fairness in terms of content refers to impartial transactions that block out any possibilities of the chairman of the corporate group acting in his private interest. In the case of Korean Air bailing out Hanjin, the meeting of board of directors were held five times and a thorough review was conducted on the risks involved in the loans being repaid or not. After the review, measures to guard against undesirable scenarios were established before finally deciding on bailing out Hanjin. As such, there are no issues. In terms of the fairness of content, too, there were practically no room for the majority shareholder or controlling shareholder to pocket profits at the expense of the company. This is because the continued aid offered to a financially troubled company (i.e. Hanjin Shipping) was a posing a burden to even the controlling shareholder. This writer argues that the concept of the interest of the entire corporate group needs to be recognized. That is, it must be recognized that the relationship of control and being controlled between parent company and affiliate company, or between affiliate companies serves a practical benefit to the ongoing concern and growth of the group and is therefore just. Moreover, the corporate group and its affiliates, as well as their directors and management must recognize that they have an obligation to prioritize the interests of the corporate group ahead of the interests of the company that they are directly associated with. As such, even if Korean Air offered a loan to Hanjin Shipping without collateral, the act cannot be treated as an offense to law, nor can the directors be accused of damages that they bear the responsibility of compensating under civil law.

• Journal of Navigation and Port Research
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• v.31 no.3 s.119
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• pp.247-252
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• 2007

The container crane is one of the most important equipments at container terminal. If its working time in cycle could be reduced then container terminal efficiency and service level can be increased. So there are many i1forts to reduce working time of container cranes. It means how to design the controller with good performance which has small overshoot and swing motion of container crane. We, in this paper, present a state feedback controller based on LQ theory incorporating a RCGA which means real-coded genetic algorithm RCGA can search state feedback gains under given objective function. A set of simulation works are carried out in order to prove the control effectiveness of the proposed methods.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2004.11a
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• pp.281-286
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• 2004

It's important to operate the yard for improving to the productivity in container terminal effectively. Because the automated container terminal(ACT) has storage yard of automation and horizon, it's character is different from conventional terminal. As the automation yard in ACT is operated by the automated equipments, it needs to an efficient storage plan which is connected the automated equipment, the external truck, the shipment etc.. Hut the traditional method of storage plan is the space assignment problem. The efficiency of yard decreases and it is brought about increase of shipment time, because real-time automated equipments and present yard status is not reflected in. In order to solve this problems, we propose the algorithm for real-time storage location of container considering shipment plan, yard status and the state of ATC.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2004.11a
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• pp.311-316
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• 2004

LMTT (Linear Motor-based Transfer Technology) is a horizontal transfer system for the yard automation. which has been proposed to take the place qf AGV (Automated Guided Vehicle) in the maritime container terminal. the system is based on PMLSM (Permanent Magnetic Linear Synchronous Motor) that consists of stator modules on the rail and shuttle mr. It is desirable to reduce the weight of LMTT in order to control the electronic devices with minimum energy. In this research structural optimization for a mover of shuttle mr is performed to minimize the weight satisfying design criteria the objective function is set up as weight. On the contrary, design variable is considered as transverse, longitudinal and wheel beam's thickness and shape variable determining the dimension toward high direction and the constraints are the stresses.