• Journal of the Korean Society of Propulsion Engineers
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• v.21 no.1
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• pp.104-111
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• 2017

A new explosive bellows, which has a diameter of 8.0 mm and a length of 25.4 mm, was developed for a warhead fuze. The new explosive bellows delivers a thrust of 4.5 kgf over a stroke of 25.4 mm. A new gas generator containing BP/MTV ignition charge was also developed and the output test equipment, which measures the length of spring compressed by the function of explosive bellows, was also devised. In order to find out that the new explosive bellows meets the design requirements, the sensitivity tests and output tests were conducted. The test results show that the new explosive bellows meets the requirements and can be applicable to a warhead fuze.

• Journal of Adhesion and Interface
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• v.12 no.3
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• pp.94-98
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• 2011

Ballistic property of Heracron/phenol composites was evaluated as a function of polyurethane (PU) type and their loadings. First, prepregs of phenol and polyurethane were prepared by spray coating on Heracron fabric and then they were utilized to prepare composite by varying their ratio. Next, they were consolidated at $150^{\circ}C$ for 25 min at $150kg/cm^2$ pressure and then ballistic property was measured with 1.1 g FSP (22 cal). V50 was evaluated interms of polyurethane type and ratio of phenol/PU prepreg.

• The Korean Journal of Archival Studies
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• no.4
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• pp.3-30
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• 2001

It is clearly stated in the current records law that presidential records should be collected and kept. Despite of the significance of this regulation it is also undeniable that there must be some preconditions for the enactment of this legal regulations. First, it needs the compatible device for promoting the production of presidential records. Second, it must be considered that presidential records should be selected and transferred from the Committee for taking over presidency. And last, we are confronted by the problem of establishing presidential archives. After all, from the starting point we should overcome a number of serious problems for the administration of the presidential records. In this article I tried to discuss these problems and to make some suggestions for the solution of these problems. In my opinion, revision of the records law is in some points necessary. Basic principle of management of presidential records must be discussed for the revision and enactment of 'presidential archives and presidential records law'. Just several problems concerning managing agency of presidential records are pointed out here. Presidential records have important historical values. The government must be responsible for the preservation and sound management of them. The citizenship also must support the reform of the records management. It means an open and public discussion on the reform of national records management system.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.47 no.6
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• pp.429-437
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• 2019

This paper deals with a ZEM (Zero-Effort-Miss) based guidance law for the interception of moving targets and characteristics of the guidance law according to time-to-go estimation methods. To derive the ZEM vector feedback guidance command, we introduce a polynomial function with unknown coefficient, and then we determine the coefficient to satisfy initial and terminal constraints. Since the directions of the guidance command and ZEM vectors are adjusted by the time-to-go, general time-to-go estimation methods are proposed, which can generate the vertical and horizontal guidance commands with respect to an arbitrary reference frame. By performing various numerical simulations, the performance and characteristics of the proposed methods are investigated.

• The Korean Journal of Archival Studies
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• no.51
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• pp.337-375
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• 2017

The Agency of Employment and Labor produces various records that are related to labor history subject while performing its functions such as labor supervision. Some valuable records were discarded even if they are worthy enough to be researched from a historical perspective. Thus, this article contributes to classifying the main subjects and the main agents of an action in view of macrohistory and microhistory. Some examples of the records that require prolonged preservation were also presented by each issue. Furthermore, this article proposes a dramatic improvement of the records schedule. It also presents other issues as the foundation of the valuation standard based on the subject including the conversion of the strategy of archival appraisal, and selection that combines the function and the subject.

• Journal of the Korean Society of Safety
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• v.36 no.4
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• pp.88-98
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• 2021

Korean industry has achieved dramatic growth in a short time through continuous technical innovations. However, safety consciousness and management have not kept pace with industry growth. The characteristics of industrial accidents in socio-technical systems have become so complicated that it has been challenging for safety professionals to implement effective preventive measures because it is difficult to determine what is happening in the complex workplace. Thus far, they have focused on technical improvements and the requirements of OSH regulations to avoid legal responsibility. Accordingly, this study has used the systemic analysis method to explain the emergence of something unexpected in complex and multi-layered business structures, which is usually related to the variabilities of humans and organizations. This study chose a shipyard where a few fatal accidents had occurred because the shipbuilding industry includes numerous variabilities, including obtaining orders, manpower supply, procurement, etc. Systemic analysis progressed using FRAM based on two accident cases related to the truss platform used in LNG vessels. The outcome shows that each function within the system has its variabilities and has become coupled or dependent on other functions, increasing the possibility of accidents. This analysis method can provide OSH professionals with practical techniques for explaining what is happening in a complex socio-technical system and how to take proper measures.

• Asia-Pacific Journal of Business
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• v.11 no.1
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• pp.27-44
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• 2020

Purpose - This study examines the factors that influence the performance of contract farming by agricultural cooperatives from the agency theory and resource-based view of the firm. Design/methodology/approach - This study collected 1,090 data related to a sample of contract information between agricultural cooperatives and producers from national agricultural cooperatives federation. In order to examine the performance of contract farming, we use the multiple regression analysis. Findings - Incentives may reduce agency problems by increasing producers' motivation and discouraging their opportunistic behavior. Total asset size and education expenses function like resources that lessen the risks coming from environment uncertainty, and also facilitate the contract farming between producers and agricultural cooperatives. Research implications or Originality - By analyzing the factors that influence on the performance of contract farming between producers and agricultural cooperatives, we propose that incentives, and resources may improve the performance of contract farming between agricultural cooperatives and producers. Overall, the contract farming can co-create the economic efficiency and effectiveness while minimizing risks and uncertainty.

• Journal of the Korea Institute of Military Science and Technology
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• v.25 no.2
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• pp.151-159
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• 2022

In this paper, we implement a digital multi-beamformer using FPGA(Field Programmable Gate Array) which has advantages in parallel and real-time data processing. This is accomplished through the use of not only high-speed data communication but also multiple beam forming, which is currently required by MFR(Multi Function Radar). As a result, the beamformer can process 24 Gbps throughput in real-time and form 5 digital beams at the same time. It is also compared to the results of Matlab simulations. We demonstrate how an implemented beamformer can be used in an MFR system by using a digital array antenna.

• Journal of the Korean Society of Visualization
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• v.19 no.3
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• pp.92-98
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• 2021

Large Eddy Simulation (LES) has been popularly applied and used in the last several decades to simulate turbulent boundary layer in the numerical domain. A fully developed turbulent boundary layer has also been applied to predict the complicated wake flow behind bluff bodies. In this study we aimed to generate an artificial turbulent boundary layer, which is based on an exponential correlation function, and generates a series of realistic three-dimensional velocity data in two-dimensional inlet section which are correlated both in space and in time. The results suggest its excellent capability for high Reynolds number flows. To make an effective generation, a hexahedral mesh has been used and Cholesky decomposition was applied to possess suitable turbulent statistics such as the randomness and correlation of turbulent flow. As a result, the flow characteristics in the domain and fluctuating pressure near the wall are very close to those of fully developed turbulent boundary layers.

• Journal of the Korea Institute of Military Science and Technology
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• v.27 no.3
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• pp.364-374
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• 2024

Today, risks created by uncertainty must be managed for successful project execution. From this perspective, applying a risk management process is very important for successful defense systems test works. This paper describes 'the implentation of risk management process for test work' carried out by DTERI's process improvement activities. In this study, the concept of risk management process, and details of the risk management process are examined through PMBOK and ISO/IEC/IEEE 15288, CMMI. After that, we defined 'Standard Process for Risk Management' of defence systems test works. And, we describe 'Risk Management Function' of DTERI's Project Management System(PMS) and the risk management process of DTERI. Finally, the effectiveness of the risk management standard process is verified through quantitative analysis.