• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.25 no.2
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• pp.172-182
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• 2014

In this paper, is is presented the result of design and fabrication for X band T/R module using in active array radar. The high power RF circuit was fabricated using GaN element, so that high power and high efficiency was fulfilled comparing with the previous T/R module that have under 50 W output power for X band. Designed X band T/R module demonstrated 200 W(53 dBm) peak power, 20 us pulse width with 0.4 dB pulse droop and 20 % duty cycle. And it has characteristics of 26 dB receive gain and 4.5 dB noise figure. The structure was applied to prevent serious damage of receive path and GaN HPA by transmitting power during trasmit time of a pulse radar.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.11
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• pp.1667-1674
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• 2010

The fatigue life is estimated while determining the reliability of aircraft structures. In this study, the estimation of fatigue life was carried out on the basis of a cumulative damage theory; the working S-N curve and the equivalent stress on the engine support structure significantly affect the safety of the aircraft. The maximum stress observed was 1,080 MPa in the case of scissors link under crash load condition, and there was a 5% margin for the allowable stress corresponding to the temperature reduction factor. The maximum stress was 876 MPa, and the stress equation coefficient had a maximum value of 0.019 MPa/N in the case of scissors link under fatigue loads. In the results of the fatigue life analysis, the safety life in a fretting area of scissors link upper part was 416,667 flight hour, and other parts showed to infinite life. Therefore, it was demonstrated that the fatigue life requirement of aircraft engine support structure (scissors link, straight link) could be satisfied.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.4
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• pp.592-598
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• 2017

The purpose of this study is to suggest a new inspection period of ${\triangle}{\triangle}$ guided missiles by analyzing their reliability using field data. The ${\triangle}{\triangle}$ guided missile has an inspection period of five years which was determined using prediction data during its development process. However, from the analysis of its field data, it was shown that the inspection period could be extended to more than 18 years. Based on this result, a policy is proposed to reevaluate the inspection period by means of practical reliability tests.

• Journal of Korea Society of Industrial Information Systems
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• v.24 no.5
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• pp.105-113
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• 2019

Korean military uses 'Tactical information communication network' to exchange information between units. In this study, we developed a media processing board for multi-party voice and video telephony based on open source software. On the other hand, in order to apply open source software for weapon systems and parts that are mounted on weapon systems, appropriate review is required according to the weapon system software development and management manual of the Defense Acquisition Program Administration (DAPA). In this study, the analysis of the requirement items was performed and the appropriate countermeasures were proposed for the open software applied to the media processing board with respect to 'the guidelines for the application of weapon systems to open source software', an appendix to the DAPA's manual.

• Korean Journal of Culture and Social Issue
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• v.26 no.3
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• pp.329-349
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• 2020

Confirmation bias is well known to be the cause of widespread misjudgment in the field of forensic decision-making. In this study, we examined the psychological mechanisms by which confirmation bias affects intentionality judgment in serious injury and death cases that combine the moral characteristics of the perpetrator and victim differently. As a result, participants perceived the case as a more typical criminal case when both the perpetrator and victim were bad people, and gave higher intention to perpetrators' actions in these typical crimes. In particular, it was found that people with a high degree of confirmation bias highly judge the intention of the offenders in a consistent way with the stereotype of criminal cases. However, in serious criminal cases, the moderate effect of confirmation bias has disappeared and only the effect of crime typicality has existed. Finally, we discussed implications of this study and ways to reduce bias in intentionality judgment.

• Journal of Family Resource Management and Policy Review
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• v.26 no.1
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• pp.15-26
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• 2022

The first purpose of this paper was to investigate whether wives' income contributions affect the time spent on housework by dual-earner couples. The second purpose was to investigate period interaction effects on the effect of wives' income contributions. For this, Korean Time Use Survey data 2004-2019 was analyzed. The analysis target was dual-earner couple aged 20-59 years. The dependent variable was time spent on housework, and the analysis method was tobit regression. According to the results, there were three findings: First, there was a U-shaped relation between wives' income contributions and wives' housework time. Second, this relationship became stronger as time progressed. Third, although wives' income contributions positively affected husband housework time, husband housework time was actually zero before 2019. These results demonstrated that not economic perspective, but gender perspective, is more useful for understanding dual-earner couples' division of housework.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.3
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• pp.91-99
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• 2019

Naval Ships have a number of requirements related to performance. Naval ship acquisition takes a long time from initial planning to delivery, and various products such as drawings and reports are created. In complex systems, such as naval ships, it is difficult to maintain the required traceability through these outputs. The basic design of the ship is an important step to determine the specifications, performance, and equipment of the ship. It is necessary to apply the systematic requirements management process. The basic design manages the requirements in accordance with the systems engineering-based technical review process, but the actual system architecture design process is not presented. The traceability between the requirements and the functional and physical architectures of components is unclear. This paper examined how to design the system architecture required for specification and system design, and the design results were verified using SE-based technical review process for requirements management. A step-by-step process for designing a submarine system architecture is presented and verified using the SE technical review. This facilitates the specification of the requirements and system architecture design, and supports traceability management and verification of the requirements. The proposed process can be applied in various ships including submarines.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.11
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• pp.96-104
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• 2018

Military vessels are complex weapon systems consisting of various integrated onboard equipment. Since their acquisition of military equipment takes a long period of time and a prototype ship is deployed and tested, vessel development has relied on its proprietary process. However, due to the growing complexity of onboard equipment technology, application of systems engineering (SE) process has become indispensable. Nonetheless, an effective design process complementing the existing design with the SE has not yet been developed. As such, we have studied an improved basic design process for submarines based on SE. To do so, we analyzed the processes for the basic design, technical review, and requirement management. Included reviews and requirements are SRR, SFR and PDR, and SSRS, SSS, and SSDD. By combining the results in the SE framework, we built an improved basic design process that can be applied in parallel with the SE-based technical review and requirement management. To assess the process, we applied our proposed model to the submarine development undergoing the basic design phase. It is possible to effectively manage the requirements, design artifacts and improve traceability, and also utilize them as test and evaluation materials. The SE-based basic design process is expected to be useful in other kinds of vessel design.

• Journal of Korea Technology Innovation Society
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• v.16 no.1
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• pp.252-278
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• 2013

Many countries implement an offset program as a method of the acquisition of modern military technology for enhancement of the domestic military strength. Offset agreements are made based on the value, not a monetary unit. The value should be above minimum threshold fixed by the related regulation. Hence, technology valuation model which is objective and reasonable is required vitally. At present, some defense related organizations such as DTaQ, ADD valuate the proposed technology by using their own method. However, due to the lack of differentiation of valuation analysis indicators for various technologies, existing offset valuation models are inadequate to consider whole characteristics of such technologies. In this paper, we developed four sets of offset valuation analysis indicators considering the characteristics of each technology, parts production, depot maintenance, military equipment performance upgrade, and R&D related technology, by using the Delphi method. Also, we structurized those indicators in each technology by using the factor analysis. Through applying developed indicators, it is expected that technology valuation in the offset program would be more credible and accurate. Ultimately, it gives greater bargaining power to negotiators in the procedure of the offset negotiation.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.10
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• pp.48-54
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• 2020

DMSMS (Diminishing Manufacturing Sources and Material Shortage) is increased by developing the scientific technique and downsizing the military part market. DMSMS affects the increase in total life cycle costs and serviceability. Therefore, advance control for parts is important to reduce the cost, and a database is needed to share information on the DMSMS. A task needs to be performed continuously by setting the major control item to management more efficiently. The purpose of this study was to deduce the major control item for the DMSMS management system. Thus, the pre-control item basis of the DAPA (Defense Acquisition Program Administration) Manual and the SD-22 Manual were first selected, and the results of the survey were analyzed by AHP (Analytic Hierarchy Process) method. Fifteen of the detailed items were stratified into three criteria (Impact, Probability, and cost of the DMSMS), and each weight for the items was calculated using a nine-point scale survey. The AHP survey was executed with 25 specialists in the DMSMS management field, and the score of consistency ratio over 0.1 was excluded. The model explained the results and suggested future directions for development.