• Journal of Navigation and Port Research
• /
• v.36 no.1
• /
• pp.1-7
• /
• 2012

A concept of the "e-Navigation" was introduced in 2005 and implementation strategies are under way by IMO/IALA in the maritime safety area. Specially VTS is an important maritime traffic monitoring and aids to navigation system which is aims to improve safety, navigation efficiency and protect the marine environment. The demand of the inter-VTS networking has been increased and standardization is underway for realization of shore side collaboration for maritime safety in IALA. But there may be security problems in the inter-VTS networks if they have not proper security mechanism. The hacking of realtime ship position and sensitive maritime surveillance information caused a critical accident of vessel, human life and environment by terrorist. This paper aims to design of a secure inter-VTS network structure and related security protocol for secure sharing of sensitive maritime data.

• Journal of Navigation and Port Research
• /
• v.43 no.6
• /
• pp.395-402
• /
• 2019

The development and operation of the MASS (Maritime Autonomous Surface Ship) is being actively discussed for more efficient and safer maritime transportation solutions. The autonomous navigation technology has positive aspects such as the prevention of marine accidents, improvement of fuel efficiency of ships and cost reduction, and negative aspects such as job loss, task change, and security problems. It is expected that there will be new human element issues such as the situation awareness of remote operators, because the shore-based control will be conducted when fully autonomous ships are in operation. In this paper, we consider major human element issues that should be factored in the development and operation of MASS, and suggest a method of HRA (Human Reliability Analysis) for P IFs (Performance Influencing Factors) of the remote operators that are expected according to the shore-based control.

• Journal of Ocean Engineering and Technology
• /
• v.22 no.6
• /
• pp.88-94
• /
• 2008

The concentration of atmospheric carbon dioxide (CO2), which is one of the major greenhouse gases, continues to rise with the increase in fossil fuel consumption. In order to mitigate global warming the amount of CO2 discharge to the atmosphere must be reduced. Carbon dioxide capture and storage (CCS) technology is now regarded as one of the most promising options. To complete the carbon cycle in a CCS system, a huge amount of captured CO2 from major point sources such as power plantsshould be transported for storage into the marine or ground geological structures. Since 2005, we have developed technologies for marine geological storage of CO2,including possible storage site surveys and basic design of CO2 transport and storage process. In this paper, the design parameters which will be useful to construct on-shore and off-shore CO2 transport systems are deduced and analyzed. To carry out this parametric study, we suggested variations in thedesign parameters such as flow rate, diameter, temperature and pressure, based on a hypothetical scenario. We also studied the fluid flow behavior and thermal characteristics in a pipeline transport system.

• International Journal of Naval Architecture and Ocean Engineering
• /
• v.10 no.1
• /
• pp.95-102
• /
• 2018

This paper proposes a dual lifting and its cooperative control system with two different kinds of floating cranes. The Mega-erection and Giga-erection in the ship building are used to handle heavier and wider blocks and modules as ships and off-shore platforms are enlarged. However, there is no equipment to handle such Tera-blocks. In order to overcome the limit on performance of existing floating cranes, the dual lifting is proposed in this research. In the dual lifting, two floating cranes are well-coordinated to add up the lift capabilities of both cranes without any loss such that virtually a single crane is lifting, maneuvering and unloading. Two main constraints for the dual lifting are as follows: First, two barges of floating cranes should be constrained as a rigid body not to cause a relative motion between two barges and main hooks of the two cranes should be controlled as main hooks of a single crane. In order words, it is necessary to develop the cooperative control of two floating cranes in order to sustain a center of gravity of the module and minimize the tilting angle during the lifting and unloading by the two floating cranes. Two floating cranes are handled as a master-slave system. The master crane is able to gather information about all working conditions and make a decision to control the individual hook speed, which communicates the slave crane by TCP/IP. The developed control system has been embedded in the real floating crane systems and the dual lifting has been demonstrated five times at SHI shipyard in 2015. The moving angles of the lifting module are analyzed and verified to be suitable for hoisting control. It is verified that the dual lifting can be applied for many heavier and wider blocks and modules to shorten the construction time of ships and off-shore platforms.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.41 no.6
• /
• pp.681-688
• /
• 2016

Several VHF bands for the use in analog communications has been changed to those for the use in new maritime digital communications by WRC-12. ITU-R M. 1842-1 has been also standardized, recommending the characteristics of maritime digital communication systems. In addition, a Shipborne Ad-hoc Network (SANET) has been introduced by IMO in order to provide ships, which cannot be connected to a shore directly, with maritime digital data exchange services with the help of ad-hoc communication. In this paper, several functionalities of the SANET, including channel access, route determination to a shore, and data exchange, are verified via sea trials. It is expected that the SANET can be applicable to collecting and analyzing maritime information, facilitating the entry and departure of vessels, and the communication infrastructure of e-navigation.

• Journal of KIISE:Computing Practices and Letters
• /
• v.8 no.4
• /
• pp.376-388
• /
• 2002

Recently, although there are strong requirements to manage multimedia data, there are a few researches on efficient storage and retrieval of multimedia data. In this paper, we design an object storage engine which can store and retrieve various multimedia objects efficiently. For this, we design an object manager for storing a variety of multimedia data and an inverted file manager for indexing unformatted text objects. In addition, we implement the objects storage engine which can support concurrency control and recovery schemes of DBMS by integrating the object manager and the inverted file manager with the SHORE low-level storage system. Finally, we develope a TIROS(Thesis Information Retrieval using Object Storage engine) system in order to verify the usefulness of our object storage engine.

• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.7 no.1
• /
• pp.57-69
• /
• 1995

The development of a finite difference model for cross-shore sediment transport prediction in the surf tone due to the storm surge event is presented in this paper. Using the inhomogeneous diffusion equation with moving boundaries. the present numerical model is found to be robust and efficient and does not possess a number of restrictions imposed in Kriebel and Dean's(1985) numerical model. Our numerical model is validated through comparison with the analytical solution. the data of a large-scale experiment and the field data of Hurricane Eloise. The Present model if able to predict the averaged volumetric erosion rate of a beach due to the time-varying real storm surge hydrographs and satisfies the conservation of sediment between eroded volume in the onshore region and deposited volume in the offshore region. In addition. the present model is able to reasonably predict the recession of a beach with wide berm and dune. and can describe the change of a breaking point by the offshore deposition. From the sensitivity analysis or the present numerical model with various input parameters, it is concluded that the present numerical model is able to analyze the beach change in a reliable manner including the effects of different sizes of sediments.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.43 no.4
• /
• pp.190-197
• /
• 2020

Recently there was an incident that military radars, coastal CCTVs and other surveillance equipment captured a small rubber boat smuggling a group of illegal immigrants into South Korea, but guards on duty failed to notice it until after they reached the shore and fled. After that, the detection of such vessels before it reach to the Korean shore has emerged as an important issue to be solved. In the fields of marine navigation, Automatic Identification System (AIS) is widely equipped in vessels, and the vessels incessantly transmits its position information. In this paper, we propose a method of automatically identifying abnormally behaving vessels with AIS using convolutional autoencoder (CAE). Vessel anomaly detection can be referred to as the process of detecting its trajectory that significantly deviated from the majority of the trajectories. In this method, the normal vessel trajectory is gridded as an image, and CAE are trained with images from historical normal vessel trajectories to reconstruct the input image. Features of normal trajectories are captured into weights in CAE. As a result, images of the trajectories of abnormal behaving vessels are poorly reconstructed and end up with large reconstruction errors. We show how correctly the model detects simulated abnormal trajectories shifted a few pixel from normal trajectories. Since the proposed model identifies abnormally behaving ships using actual AIS data, it is expected to contribute to the strengthening of security level when it is applied to various maritime surveillance systems.

• Journal of the Korean Institute of Navigation
• /
• v.2 no.1
• /
• pp.15-34
• /
• 1978

This paper deals with the study of the effective reflecting area of the land targets for the improvement of the map of the Radar Simulator, through the analysis of the pictures on P.P.I Scope. It is very important to anticipate the effective refiecting area of land marks, either forinterpretation of radar scope or for simulating accurately the radar scope, but has seldom been studied theoretically or experimentarily, especially on the stand point of simulating the radar scope. Most of the maps of Radar Simulator in use are made without consideration of the effective reflecting area of land marks, so that the P.P.I. Scope of the Radar Simulator may show much different pictures from the actual shore line and other targets. This paper has derived the following conclusiions by experimental procedures. 1. The effective area of the land target greatly varies according to the gradient of the contours, roughness and material of the land surfaces, so that simulator maps of uniformly coated land taret practically used now many be effectively improved by varying the intensity of the land marks proposed in this paper. 2. The intensity of the land targets on the P.P.I. is also related much to the distance from the radar, so that the precalculation of this effect may results in a much simulated P.P.I. picture improved. 3. If the ambient condition is constant, the intensity of the picture increases as the height of the targets is increased.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.7 no.3
• /
• pp.423-436
• /
• 2003

Submarine optical fiber cable construction consists of marine survey, PLGR(Pre Lay Grapnel Run), shore-end-work, laying order. PLGR is the work process which removes the oceanic contaminations(ropes, wires, nets etc.) in the route before laying the submarine optical cable. This PLGR is work to ease the cable lay safely in seabed, improve the performance of Plough and ROV((Remotely-Operated Vehicle) laying work, and protect laying equipment. This paper presents the optimization algorithm implementation of KP(Kilometer Post) and XTE(Cross Track Error) to manage marine survey and PLGR work efficiently. In this paper, we composes overall PLGR work, and proposed optimization algorithm of KP and XTE. For the validity evaluation of this paper, KP and XTE decision algorithm are implemented and tested.