• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2013년도 추계학술대회 논문집
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• pp.667-668
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• 2013

• 한국소음진동공학회논문집
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• 제24권11호
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• pp.907-918
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• 2014

In this study for the prediction of 3D underwater radiated noise pattern, a comparison between the proposed method(DHIE, Discrete Helmholtz Integral Equation) and the 3D underwater radiated noise calculation results using the measurement of near-field acoustic pressure data is performed. The near-field acoustic pressure in water is measured for the calculation of the far-field radiated noise pattern and the far-field acoustic power. Also the vibration field of the underwater structure is measured in simultaneously. Using the total far-field acoustic power and the vibration field on the surface of the structure, the proposed method(DHIE) can predict the underwater radiated noise pattern of the far-field The predicted results show the reasonable agreement within about 5dB comparing with the experiment result.

• 한국안전학회지
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• 제32권3호
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• pp.105-111
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• 2017

The number of natural disasters has risen dramatically such as earthquakes, typhoons and floods. However, the scope of disasters expand in today's society due to the rapidly changing environment. This study is to suggest improvements for disaster management system in defense field in order to reduce possible loss or damage from a huge disaster. Through two case studies from the United States and Japan, this research aims to support policy making of disaster management system in defense field.

• 한국컴퓨터정보학회논문지
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• 제23권10호
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• pp.173-180
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• 2018

In this paper, we analyzed key keywords and research themes in the field of defense research using keyword network analysis and tried to grasp the whole knowledge structure. To do this, we extracted data from 2,165 research data from defense related research institutes from 2010 to 2017 and applied the Pareto rule to the number of abstracts of words and the number of links between words, We extracted a total of 2,303 words based on the criterion and extracted 204 final key words through component analysis. By analyzing the centrality and cohesiveness through these key words, we confirmed the concept of core research in the defense field and derived a total of 7 large groups and 16 small groups of each group in the knowledge structure of the defense area.

• Journal of Magnetics
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• 제20권1호
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• pp.62-68
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• 2015

This paper presents an experimental technique to accurately separate a permanent magnetic field and an induced one from the total magnetic fields generated by a steel ship, through compensating for the Earth's magnetic field. To achieve this, an Earth's magnetic field simulator was constructed at a non-magnetic laboratory, and the field separation technique was developed, which consisted of five stages. The proposed method was tested with a scaled model ship, and its permanent and induced magnetic fields were successfully extracted from the magnetic field created by the ship. Finally, based on the separated permanent magnetic field data, the permanent magnetization distribution on the hull was predicted by solving an inverse problem. Accordingly, the permanent magnetic fields generated by the ship can easily be calculated at any depth of water.

• 품질경영학회지
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• 제46권3호
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• pp.497-508
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• 2018

Purpose: The purpose of this study is to research the revision efficiency of the referenced specifications/standards for raw and subsidiary materials in the field of national defense. Methods: Firstly, it was carried out to investigate the all of the Korean military drawings and establish the database for specifications/standards referenced in the field of national defense. Secondly, it was reviewed the validity of referenced specifications/standards of raw and subsidiary materials. Finally, proposal documents were made for invalid referenced specifications/standards of raw and subsidiary materials in order to suggest alternative specifications/standards. Results: All of the specifications/standards referenced in the Korean military drawings were 11,924 kinds and raw and subsidiary specifications/standards were 2,711 kinds. The proposal documents for revision of invalid referenced specifications/standards were suggested and approved by the military procurement standardization committee of DAPA (Defense Acquisition Program Administration). Therefore, the revision process of 472 kinds of referenced specifications/standards and 160,177 papers of the Korean military drawings were finished. Conclusion: Based on the results of this investigation, it could be significantly reduce to administrative costs and efforts through revision of referenced specifications/standards instead of conventional engineering change.

• 한국산업융합학회 논문집
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• 제23권2_2호
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• pp.225-232
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• 2020

In this paper, we introduce the results of investigating and overhauling bearing drawings in the defense field, and propose an effective bearing drawing management system. We identify the features and performance items that must be regulated in the bearing drawing. After reviewing the validity of the bearing drawings, we classify the incorrect drawings by factor. To achieve greater effect, standardized formats are needed to incorporate into the drawing in the early stage. We propose the introduction of a bearing drawing management system so that the developing bearing technology can be applied quickly to the defense sector. As other elementary parts of the machine have similar problems, we think this study will help develop improvement plans.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 제39회 하계학술대회
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• pp.876-878
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• 2008

The galvanic corrosion of a vessel, or systems fitted to minimize the ship's corrosion such as ICCP(Impressed Current Cathodic Protection) system and sacrificial anodes, can lead to significant electrical current flow in the sea. The presence of vessel's current sources associated with corrosion will give rise to detectable electric field surrounding the vessel and can put it at risk from mine threats. For this reason, it is necessary to design corrosion protection systems so that they don't only prevent a hull corrosion but also minimize the electric field signature. In this paper, we describe theoretical backgrounds of underwater electric field signature due to corrosion and corrosion protection system on naval vessels and analysis results of the electric field according to ICCP anode arrangement.

• 한국IT서비스학회지
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• 제20권6호
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• pp.151-162
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• 2021

Since 2012, the Navy has been conducting a defense experiment project to evaluate the possibility of military application by introducing new technologies related to excellent private informatization in the defense field. There are many projects that have spread because they are suitable for military use, but some have ended as experimental projects themselves because they do not meet the military's required performance. Continuous development is required as increasing the spread rate by successfully carrying out defense experiment projects is the basis for defense reform. This study analyzed the performance of major projects carried out by the Navy and presented considerations for the development of defense experiment projects to be carried out by the Navy in the future. The main achievements were derived in various ways in terms of project performance and system operation, and the considerations can be summarized in the field of raising business requirements, securing resources for system operation, determining the size of companies for project execution, and security measures. The research results can be used as data to determine the required defense experiment project and efficiently carry out the project.

• 한국소음진동공학회논문집
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• 제24권12호
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• pp.969-976
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• 2014

Nowadays, it is required for naval ships to estimate 3D underwater radiated noise pattern in all direction at peak frequencies of hull vibration for the reduction of being detected and doing the effective operation. For this purpose, the numerical method has to be developed to calculate 3D underwater radiated noise pattern with experimental data. It is very difficult to obtain the experimental data for the real ship. Alternative to get the experimental results is to use NAH(near-field acoustic holography) in acoustic tank with experimental model. Application of NAH in acoustic tank for the experimental model needs some investigation of reflection wave from the wall of the acoustic tank and unmeasured zone of the experimental model due to the supporting structure for it. In this study, the effect of reflection wave in the acoustic tank and unmeasured area of the experimental model when using the NAH was investigated with experiment and numerical model. From these, it is known for the error due to reflection wave can be reduced when the distance between the measurement plane and source is being shorten. Also, unmeasured area of the experimental model gives rise to some error in the estimation of the far-field acoustic pressure.