This paper aims to introduce a case of improving the performance of aged naval ships' Identification Friend or Foe(IFF) equipment from Mode 4 to Mode 5, thereby enhancing operational capabilities and overcoming integration limitations. Since 2019, South Korea has been conducting a project to replace IFF equipment across the entire military, categorized into naval ship, air force aircraft, surveillance and reconnaissance, and protection. Among these, three naval classes without combat systems required not only an upgrade of their IFF equipment from Mode 4 to Mode 5 but also an integration capability that would allow them to maintain the same fire control procedures by linking with existing naval gun fire control systems. To implement this integration function, the signal processing methods of the existing IFF equipment were analyzed, and based on this, the integration function was implemented in a signal converter module. This paper is expected to serve as an important resource for future performance upgrades of internal equipment in aged naval ships.

The research aimed to develop a high-efficiency plate-type heat exchanger for exhaust gas using computational fluid dynamics (CFD) thermal analysis based on the plate shape, and to identify the optimal shape. Following this, a water/air plate heat exchanger was manufactured, and its characteristics were studied experimentally. As the Re number increases on the gas (or air) side, the heat transfer rate increases significantly, whereas an increase in the Re number on the water side leads to a smaller increase in heat transfer. This is attributed to the larger convective heat resistance on the gas side, causing a substantial reduction in gas-side heat resistance as gas velocity increases, resulting in a considerable overall reduction in heat resistance. The fluid flow pressure drop showed similar results between the CFD calculations and experimental outcomes.

Despite the presence of the p-Channel MOSFET inrush current limiter circuit within the power supply unit of military radar, The internal MOSFET and DC-DC Converter has been damaged due to the high inrush current. In this paper, the cause of the high inrush current was identified by analyzing the p-Channel MOSFET inrush current limiter circuit. Based on the analysis, the high inrush current was reduced by about 60% by adjusting the time constant of the source-to-gate elements compared to before improvement.

In this paper, the EMP-related standards and test methods used by the civilian and military have been introduced. The incoming EMP signal for seven military RF antennas which are the first to face EMP threats among military weapon systems have been also measured and analyzed. Overall, as the applied signal strength increased, the strength of the EMP signal entering in the antenna also showed an upward trend. The highest level of entering was observed at the peak value of the applied EMP signal, 50 kV/m. And at the peak value, all antennas received threatening signals. In particular, antennas in low frequency bands such as AM and FM were getting high voltage signals as high as thousands of volts. This means that the weapon systems linked to the antennas could suffer severe damage. Therefore, based on this paper, systematic research for EMP threat should be conducted to identify EMP vulnerabilities of major weapons systems and to devise practical protective measures.

The demand for LNG Carrier and LNG fuel ships are increasing due to global carbon neutrality declaration and ship emissions regulation of IMO, domestic shipyards pay technology fees(about 5~10% of ship price per vessel) to GTT company in France for making LNG cargo hold. Localization of LNG cargo hold is needed to reduce technology fees and engage technological competitiveness, it is important to secure the critical technology like automation process development of insulation system process. Especially, the automation rate of membrane-type insulation system is very low due to interference caused by corrugation and difficulty in securing optimal variable welding condition. In this study, to solve this problem, automatic welding is performed using developed automatic welding equipment on STS304L steel which is used in flat and corner area of membrane-type LNG cargo hold's lap joint. After welding, Cross-sectional observations and Tensile strength tests were conducted to evaluate reliability of equipment and welding condition. As a result of the test, it was confirmed that the strength of the welded zone exceeded that of base material, and secured the optimal welding condition to apply automatic welding.

We have observed a phenomenon where the internal X capacitors of the input EMI filter experienced damage during operation. To solve the problem, we have analyzed the malfunction by identifying the characteristics and operating principles of EMI filter. Based on this analysis, we have derived improvement strategies and validated them through experiments. This paper help some people prevent the similar problem when developing the similar equipment and solve the similar problem of the similar equipment.

본 연구는 간호대학생의 월경곤란증 및 스트레스가 수면의 질에 미치는 영향을 파악하기 위한 조사연구이다. 연구 대상자는 간호대학 학생 248명을 대상으로 하였고, 자료수집은 2021년 4월 20일부터 5월 18일까지 수행하였다. 자료분석은 SPSS/WIN 24.0을 이용하여 기술통계, 상관관계 및 다중회귀분석을 사용하였다. 연구결과, 간호대학생의 수면의 질은 월경곤란증(r=.20, p<.001)및 스트레스(r=.24, p<.001)와 유의한 정적 상관관계를 보였다. 간호대학생의 수면의 질에 가장 영향력이 있는 요인은 학년(β=.20, p<.001), 스트레스(β=.19, p=.004), 월경곤란증(β=.15, p=.014)으로 나타났으며 모형의 설명력은 13.4% 이었다. 이에 간호대학생의 수면의 질을 향상시키기 위해서 학년에 따른 스트레스 관리 및 월경곤란증에 대한 평가와 정보제공이 포함된 수면 관련 교육 개발을 제안하는 바이다.

Four types of metal oxide semiconductor gas sensor arrays were used to observe the aroma and spoilage odor emitted during the ripening process of plum & banana fruits. All gas sensors showed a high correlation (R=0.82~0.90) with the olfactory. The TGS 2603 sensor showed a high correlation of 0.90 between the odor generated and sensory perception of smell in the process of ripening and decaying fruits. In addition, it showed a very high correlation of 0.91 with the decay rate of the plum sample, and the significance probability through one-way ANOVA was also less than 0.05, which confirmed it as an optimal gas sensor (TGS 2603). Principal component analysis was performed using all the data. The cumulative variability was 99.54%, which could be explained only by two principal components, and the first principal component was 95.11%, which was related to the freshness of the fruit. It was analyzed as fresh fruit in the negative(-) direction and decayed fruit in the positive(+) direction.

본 연구는 국내 및 외국인 기관투자자의 투자 기간이 기업의 배당정책과 어떠한 관계가 있는지를 분석하며, 특히 Yan and Zhang(2009)의 투자자 포트폴리오회전율 계산법을 사용하여 장기 및 단기 투자자를 구분한다. 주요 분석 결과들은 다음과 같다. 첫째, 기관투자자 전체 지분율 또는 국내 및 외국인 기관투자자 지분율은 배당성향 및 배당수익률과 유의한 관계가 나타나지 않았다. 둘째, 기관투자자의 투자 기간에 따라 장기 기관투자자 지분 율은 배당성향과 유의한 양(+)의 관계가 나타났다. 반면, 단기 기관투자자 지분율은 배당성향 및 배당수익률과 유의한 관계가 나타나지 않았다. 셋째, 장기 국내 기관투자자 지분율은 배당성향과 유의한 양(+)의 관계가 나타난 반면, 단기 외국인 기관투자자 지분율은 배당성향과 유의한 음(-)의 관계가 나타났다. 이에 따라 장기 국내 기관투자자는 경영자 모니터링 역할을 수행하면서 배당 수익을 투자 목표로 추구하지만, 단기 외국인 기관투자자는 주식의 단기적인 매매를 통한 자본이득을 추구한다고 해석할 수 있다. 넷째, 장기 국내 기관투자자와 기업지 배구조의 상호작용 변수는 유의한 음(-)의 관계가 나타났다. 이에 따라 지배구조가 양호한 기업은 경영자 모니터링이 효과적으로 이루어지므로, 장기 국내 기관투자자는 배당 수익 보다는 장기적인 기업가치의 증가에 초점을 맞추는 것으로 해석된다. 다섯째, 기업지배구조가 양호할수록 경영자 모니터링이 효과적이고 대리인비용이 낮은 가운데, 배당성향이 높은 것으로 나타났다. 또한, 수익성 및 영업 현금흐름 비율이 높을수록 여유 현금흐름으로 인해 배당성향이 높은 것으로 나타났다. 이와 대조적으로 기업의 자기자본수익률이 높을수록 배당성향은 낮아지는데, 수익성이 높은 경우 재투자에 현금흐름을 사용함에 따라 배당 지급은 줄어드는 것으로 해석된다. 또한, 기업 규모가 클수록 낮은 배당성향을 나타내서 규모가 큰 기업일수록 여유 현금을 배당 지급보다는 투자에 지출하는 경향이 있다고 볼 수 있다. 이러한 분석 결과들은 한국기업들이 장기 투자 기간을 가진 국내 및 외국인 기관투자 자를 주주로서 우대할 필요가 있음을 시사한다. 이를 위해 한국 기업들은 주주들의 주요 수익원으로 배당을 중요시하면서 배당성향과 배당수익률을 높이는 재무정책을 추구할 필요가 있다. 또한 기업지배구조를 개선하는 노력과 함께 자본적 지출, R&D 지출 등을 확대하면서 장기적인 기업가치를 증대시킬 수 있을 것이다.

Structures of domestic nuclear power plants are designed to perform elastic behavior against beyond design earthquakes, but studies on the nonlinear behavior of structures have been insufficient since the beyond design earthquake. Accordingly, it is judged that it will be necessary to develop an evaluation method that considers the nonlinear behavioral characteristics to check the safety margin for a standard nuclear power plant structure. It is confirmed that the restoring force characteristics for each member level can be identified through the calculation formula, and the lateral stiffness for each story can also be easily calculated by JEAC 4601. In addition, as a result of applying the evaluation method of JEAC 4601 as a nonlinear restoring force model of the nuclear power plant, a certain degree of safety margin can be identified.

The purpose of this study was to derive practical improvement measures for the food traceability system that could improve food reliability and secure food safety. To this, in our survey May-June, 2019, 567 adult males and females were analyzed for recognition and experience of the food traceability system, measures to improve the system, and intention to make additional payments to improve the system. In the case of a food safety accident, 2.54 of 5 points were given on if the food was recalled or not. Approximately 77.4 percent of the respondents had never seen indication of a food traceability system, and approximately 93.8 percent had no access to, or experience with, using the system. Most respondents said that the food traceability system should be applied to items that need to be applied. As the volume of data that is recorded and managed by the government is recognized as high, improvement is needed. Finally, it was analyzed that the company intends to pay an additional 1.34% on average to expand its food traceability system. A more sophisticated cost analysis is needed to apply the improvements proposed to complement the plans that are acceptable to consumers and the industry.

미국 특허법 제272조는 선박을 위시한 국제운송수단에 대하여 특허권의 효력을 배제함으로써 국제 상거래의 위축을 방지하는 목적이 있다. 이는 산업재 산권 보호를 위한 파리협약 제5조의3을 국내법화한 것으로 세계 각국 특허법 역시 비슷한 내용을 규정하고 있음에도 미국 특허법 제272조의 해석이 중요한 이유는 미국이 각국의 특허법 해석과 국제 상거래에 미치는 영향이 크기 때문 이다. 미국은 연방대법원의 Brown 판결로 국제운송수단 특허권 제한법리가 이미 있었고 제272조 신설 이후에는 National Steel Car 사건 등 그 적용이 문제된 여러 재판례가 있다. 이를 통해 미국 특허법 제272조의 5가지 요건 즉, (1) 선박 (vessel), 항공기(aircraft), 차량(vehicle), (2) 상호주의, (3) 일시성 또는 우발성, (4) 운송수단의 필요에만 발명의 사용(전용성), (5) 미국에서 판매 청약 또는 판매되거나 판매될 것의 제조에 사용되거나 미국에서 수출되지 않을 것 등의 구체적 해석론을 제시할 수 있다.