• Journal of the Korean Institute of Intelligent Systems
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• v.18 no.3
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• pp.341-346
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• 2008

This paper is to develop a monitoring system with diagnosis for smart cargo sensors that is for management and maintenance of the liquid cargo ships. The main goal of the system is to achieve the total automation system of the cargo sensor. By this study, the active smart sensor for the liquid cargo ships is designed and developed that guarantees high-confidence, stability, and durability. The proposed system consists of a monitoring part of the steam pressure, high-level monitoring, over flowing monitoring, gas monitoring, and tank temperature monitoring. The signals transferred from each unit system are used for sensor diagnosis based on confidence and accuracy. Finally, in this study, the total supervisory monitoring system is developed to maintain and manage the cargo effectively based on fault diagnosis and prognosis of the each sensor system.

• Journal of Ocean Engineering and Technology
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• v.30 no.4
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• pp.243-252
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• 2016

Conventionally, the static angle of attack and static elevator tests are carried out separately to estimate hydrodynamic stability derivatives of underwater vehicles. However, it is difficult to verify the interaction between the angle of attack and elevator angle in such cases. In this study, we perform a static elevator with angle of attack test where both the angle of attack and elevator angle are varied simultaneously. The experimental results show that the angle of attack has an influence on the elevator control force and that this tendency is dependent on the sense in which the angle of attack and elevator angle are varied. We predict level flight performance using hydrodynamic derivatives estimated through this experiment. The predictions considering the effect of angle of attack show good agreement with trials conducted in the open sea.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.25 no.2
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• pp.314-319
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• 2021

Problems that satisfy various constraints while maintaining weight balance in ships or aircraft were studied. In addition, a study was conducted to solve the problem with a mathematical method under the condition that the shape and weight of the load are the same and the m×n (m and n are all odd) mesh structures. The problem is that the existing mathematical weight balancing method is not suitable for circular structures. In this paper, we studied the load stowing problem in a circular space where objects are loaded at the vertices of N equilateral polygons. Assuming that all N conformal polygons have an even number of angles, it was proved that a loading method that always maintains weight balance regardless of the variety of number of loads. By providing the structure and loading method of the drone loading ship, we showed that our method was appropriate.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.33 no.6
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• pp.367-373
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• 2021

In this study, deep learning model was set up to predict the wave heights inside a harbour. Various machine learning techniques were applied to the model in consideration of the transformation characteristics of offshore waves while propagating into the harbour. Pohang New Port was selected for model application, which had a serious problem of unloading due to swell and has lots of available wave data. Wave height, wave period, and wave direction at offshore sites and wave heights inside the harbour were used for the model input and output, respectively, and then the model was trained using deep learning method. By considering the correlation between the time series wave data of offshore and inside the harbour, the data set was separated into prevailing wave directions as a pre-processing method. As a result, It was confirmed that accuracy and stability of the model prediction are considerably increased.

• Journal of the Society of Naval Architects of Korea
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• v.59 no.5
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• pp.296-305
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• 2022

In order to investigate maneuvering characteristics of KCS in waves, captive model test in regular waves was conducted. Purpose of the test is measuring maneuvering hull forces when ship is maneuvering in waves. Model test was carried out using CPMC (Computerized Planar Motion Carriage) of ocean engineering basin in KRISO (Korea Research Institute of Ships and Ocean engineering). Total 6 degrees-of-freedom motion were fixed by two points supporting captive model test device, which is specially designed for this test. This system estimates 6 degrees-of-freedom forces and moments through 12 strain gauge signals. Mapping matrix from strain gauge signals to 6 degrees-of-freedom forces and moments was derived by a well-organized calibration test. Static drift test was conducted in calm sea and in regular waves with various wave conditions. Hydrodynamic coefficients related to drift angle were extracted for each wave conditions, and the effect of waves on course stability was analyzed.

• Journal of the Korea Society of Computer and Information
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• v.27 no.12
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• pp.121-129
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• 2022

the Naval Combat Management System(CMS) has been installed and used in various ships since its localization, and has been developed by continuously introducing the latest technology. Recently, surface ship CMS have applied server virtualization and desktop virtualization(Virtual Desktop Infra, VDI) technologies among virtualization technologies to increase system stability and limitations on the limited space and weight of ships. On the other hand, submarine CMS do not have virtualization technology applied, so there are limitations in space and weight limitations and CMS efficiency improvement. To this end, this paper proposes a next-generation submarine CMS using Docker-based server virtualization. Through performance analysis between the processor of the existing CMS and the processor to which Docker-based server virtualization was applied, it was confirmed that the method proposed in this paper is applicable to the next-generation submarine CMS.

• Strategy21
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• s.30
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• pp.63-98
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• 2012

Northeast Asia has a multi-layered security structure within which major economic and military powers both confront one another and cooperate at the same time. Major regional powers maintain mutually cooperative activities in the economic sphere while competing one another in order to secure a dominant position in the politico-military arena. The multifarious threats, posed by the North Korea's nuclear development, territorial disputes, and maritime demarcation line issues demonstrate that Northeast Asia suffers more from military conflicts and strifes than any other region in the world. Specifically, major maritime security threats include North Korea's nuclear proliferation and missile launching problems as well as military provocations nearby the Northern Limit Line(NLL) as witnessed in the Cheonan naval ship and Yeonpyong incidents. The ROK Navy has been supplementing its firm military readiness posture in consideration of North Korea's threats on the NLL. It has performed superb roles in defending the nation and establishing the Navy advanced and best picked. It also has been conducive to defend the nation from external military threats and invasion, secure the sea lanes of communications, and establish regional stability and world peace. In order to effectively cope with the strategic environment and future warfares, the ROK Navy needs to shift its military structure to one that is more information and technology intensive. In addition, it should consolidate the ROK-US alliance and extend military cooperative measures with neighboring countries in the Asia-Pacific region. Evolved steadily for the last 60 years, the ROK-US alliance format has contributed to peace and security on the Korean peninsula and in the Northeast Asian region. In conclusion, this manuscript contends that the ROK Navy should strive for the establishment of the following: (1) Construction of Jeju Naval Base; (2) Strategic Navy Equipped with War Deterrence Capabilities; (3) Korean-type of System of Systems; (4) Structure, Budget and Human Resources of the Naval Forces Similar to the Advanced Countries; and (5) Strategic Maritime Alliance and Alignment System as well as Domestic Governance Network for the Naval Families.

• Korean Journal of Heritage: History & Science
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• v.55 no.4
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• pp.242-275
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• 2022

This study tries to reveal the structure of the "Kisun"(senior envoy ship) taken by senior envoys for the 10^th to 12^th visits to Japan from the perspective of professional shipbuilding engineering focusing on the theory of the ship in the travel logs of royal envoys to Japan (Sahaengrok) written by Joseon Tongsinsa that includes 12 visits to Japan for about 200 years from 1607 to 1811. The results of the study showed that the size of Kisun for the 10^th to 12^th envoy visits was 19 Pa (把) and a half in length and 6 Pa (把) and 2 Cheok (尺) in width. The height of the Sampan was found to be 2 Pa (把) and 1 Cheok (尺) based on records in Gyemisusarok and Jeungjeonggyorinji. The structure of Kisun was different for each visit but, it was found that Kisun was mainly composed of a main deck, bow (bow plate, stem plate), stern (stern plate), Sampan, Meonge (support), Garyong (support), Sinbang, Gungji, deck, two masts and sail, Gurejjak (mast support), Panok, stern Panok, Taru, dodger, anchor reel, stairs, rail, rudder, oar, and anchor. In addition, wood and iron nails were used together for connection. It was also found that the sail was made of herbage and cotton. This study found that Kisun, which was operated for the 10^th and 12^th envoy visits, was big in terms of length and height among the Joseon Tongsinsa fleet to show the authority and dignity of Joseon and that it had passages outside on the sides of the vessel and paddles were located between the sides and Panok structure and rails were installed on four sides on the Panok, improving stability and linear beauty. The walls of Panok were decorated with the royal Dancheong pattern and fancy murals. In addition, it was found that they wished for a safe voyage by drawing a demon face on the bow. Therefore, it was revealed that Kisun, which was taken by envoys as recorded in travel logs, was made by the state and equipped with structures and functions that enabled international voyages.

• Journal of Radiation Protection and Research
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• v.40 no.2
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• pp.79-86
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• 2015

$^3He$ gas has been used for neutron monitors as the neutron converter owing to its advantages such as high sensitivity, good ${\gamma}$-discrimination capability, and long-term stability. However, $^3He$ is becoming more difficult to obtain in last few years due to a global shortage of $^3He$ gas. Accordingly, the cost of a neutron monitor using $^3He$ gas as a neutron converter is becoming more expensive. Demand on a neutron monitor using an alternative neutron conversion material is widely increased. $^{10}B$ has many advantages among various $^3He$ alternative materials, as a neutron converter. In order to develop a neutron converter using $^{10}B$ (actually $B_4C$), we calculated the optimal thickness of a neutron converter with a Monte Carlo simulation using MCNP6. In addition, a neutron converter was fabricated by the Ar sputtering method and the neutron signal detection efficiencies were measured with respect to various thicknesses of fabricated a neutron converter. Also, we developed a 2-dimensional multi-wire proportional chamber (MWPC) for neutron beam profile monitoring using the fabricated a neutron converter, and performed experiments for neutron response of the neutron monitor at the 30 MW research reactor HANARO at the Korea Atomic Energy Research Institute. The 2-dimensional MWPC with boron ($B_4C$) neutron converter was proved to be useful for neutron beam monitoring, and can be applied to other types of neutron imaging.

• Journal of Navigation and Port Research
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• v.33 no.8
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• pp.549-554
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• 2009

Wind velocity and wind direction are very important in the viewpoint of ship's safety and stability of port structure. The characteristics of wind distribution in the coast of Busan are analyzed for 10 years from 1997 to 2006 using AWS(Automatic Weather System) data. The characteristics of wind distribution of Miryang, is not affected by the land and sea breeze are also examined to understand clearly the characteristics of wind distribution in the coast of Busan. The mean wind velocity in the coast of Busan is stronger than that of Miryang. The mean wind velocitie at Youngdo and Gadukdo stations of Busan are stronger about 2.0 times than those at IlGwang, Haeundae and Daeyeon stations. The correlation a states show that the variation tendencies of monthly mean wind velocitie in the coast of Busan are very similar. The maximum monthly mean velocitie in the coast of Busan are recorded in September. This re ult is closely related to the influence of typhoon. The maximum instantaneous wind velocitie are also strong at Youngdo and Gadukdo stations and the peaks of maximum instantaneous wind $velocit^9$ are observed mainly from August to September. In the coast of Busan, the SW'ly-NNE'ly wind are prevailing in the winter and the SW'ly and NE'ly wind are predomi snt in the spring. w that the vs of wind direction in the summer and athumn are similar with those in the spring and winter, respectively.