• 한국군사과학기술학회지
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• 제21권6호
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• pp.767-775
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• 2018

To develop and check a Radar Processor Unit, checking the function and performance of the requirement is very important factor in developing Radar. General methods for verifying the Radar is simulation test, environment linkage test and field operation test, firstly, in case of requirement analysis phase, verify Radar algorithm and design by using mathematical method based simulation test method, and secondly, in case of unit test and integrated test phase, Test Equipment is set to simulate radar environment in the lab to verify radar function and performance. Lastly, field operation test phase is carried out to confirm the function and performance after it is mounted on the actual equipment. To successfully develop Radar Processor Unit, using the method of field operation test method after sufficient test cases are tested in radar environmental interlocking method in order to save cost and testing period and because of this reason, development of the Radar Processor Unit Test Equipment is becoming very important factor. In this paper, we introduce the concept of test equipment development and important factors in test equipment, which are target simulation, data processing and device interlocking.

• 한국안전학회지
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• 제33권5호
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• pp.120-126
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• 2018

The traffic accident types are largely classified into vehicle to vehicle accident, vehicle-to-person accident and single-vehicle. Especially, the single-vehicle accident types are severe when the vehicle crashed into road facilities such as bridge, piers, utility poles. The severity of single-vehicle accidents are ten times higher than that of all other accidents types. It is needed to consider to reduce accident severity. This study was conducted to develop crash worthy safety design facility to ensure the vehicle occupant safety. The simulation and the crash tests were conducted for assessment of the safety performance to check the criteria of CC2(Crash Cushion 2) level. THIV(Theoretical Head Impact Velocity) and PHD(Post-impact Head Deceleration) were used to assess occupant impact severity for crashes. The non-redirection collision test conditions for 900 kg and 1,300 kg-head on crash tests, 900 kg-1/4 offset crash tests, 1,300 kg-head on crash test with $15^{\circ}$angle were conducted. The simulation and experiment test result showed that THIV values were below 44 km/h criterion, PHD values were below the 20G. The development non-redirective crash cushion is expected to be used for the fixed object such as bridge piers for assuring occupant safety.

• 한국환경과학회지
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• 제22권9호
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• pp.1115-1129
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• 2013

The study area is located on the western coast, and the inner development construction has been ongoing since 2011. The purposes of current study are to effectively simulate and quantitatively predict a temporal and spatial distributions of water temperature and salinity due to the stages of inner development construction in saemangeum reclaimed area. The transient-state numerical modeling using EFDC model is done, and the numerical simulation results are validated reasonably by repetitive numerical model calibration procedures with respect to field measurements of water temperature and salinity. The spatial distributions of water temperature and salinity show similar trends before and after construction of the dikes. In spring season, the salinity has maximum value of 21 psu, while, in summer season, the salinity shows 7 psu in a whole modeling domain. Thus, it is clearly observed that salt water is replaced by freshwater. However, the salinity and temperature reach their initial conditions at the end of the year. The salinity after construction of the dikes is lower than that before construction of them at Mankyeong area. On the other hands, after construction of the dikes, the salinity after dredging operations is higher than that before dredging. Because drastical increasing of water volume in Saemangeum Lake leads to increasing of stagnation time at bottom layer, and salt water is easily intruded to the two estuaries. Therefore, it may be concluded that hydrodynamic characteristics on Saemangeum are dominated by either Mankyeong and Dongjin discharge or sluice gates in/out-flow amounts, and thus they must be properly considered when rigorous and reasonable predictions of water temperature and salinity according to the stages of inner development construction.

• Journal of Advanced Marine Engineering and Technology
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• 제39권4호
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• pp.468-472
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• 2015

최근 대두되는 선박배기가스 저감 등의 환경정책으로 인하여 에너지의 효율적 이용에 관심이 증가하고 있다. 본 논문에서는 함정의 에너지 효율 향상을 위하여 사용 부하에 따라 해수펌프를 제어하는 고효율 해수냉각시스템을 제안한다. 본 논문에서는 제안하는 시스템의 효과를 알아보기 위하여 추진 디젤기관의 냉각시스템을 모델링 하고 함정 운항특성을 고려한 시뮬레이션을 수행하였다. 시뮬레이션 결과 제안한 고효율 해수냉각시스템이 기존 해수냉각시스템에 비하여 약 53%의 에너지 절감효과가 있었다. 본 연구 결과는 향후 함정 추진 디젤기관의 해수냉각시스템의 성능 향상에 유용한 자료로 활용될 수 있다.

• 근관절건강학회지
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• 제31권1호
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• pp.22-30
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• 2024

Purpose: In-hospital cardiac arrest is rare, but often results in high mortality rates. Early and effective cardiopulmonary resuscitation (CPR) is crucial for survival and nurses are often the first responders. This study aimed to investigate how inter-professional attitudes and educational burdens affect self-efficacy related to CPR performance following team-based CPR simulation training. Methods: This retrospective observational study analyzed data from a satisfaction survey conducted after team-based CPR training sessions between January and November 2022. Of the 454 nurses surveyed, 238 were included in the study after excluding those with ambiguous responses. Multiple regression analysis was performed to assess factors influencing CPR self-efficacy. The factors examined included inter-professional attitudes and educational burden. Results: Higher levels of inter-professional attitudes, particularly regarding teamwork roles and responsibilities, lower educational burden, and a positive perception of CPR competence were all associated with improved CPR-related self-efficacy. Participants who reported higher engagement in teamwork, lower task load, and greater confidence in their CPR abilities demonstrated higher self-efficacy in performing CPR. Conclusion: Enhancing the competencies of nurses who may act as initial responders in CPR situations within or outside hospital settings can help save lives and support public health.

• 한국시뮬레이션학회논문지
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• 제8권1호
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• pp.113-138
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• 1999

Driven by the explosive expansion and acceptance of the Internet and its multimedia front-end, the Web, a new generation of the modeling and simulation tools have come up with the name of Web-Based Simulation (WBS). Most of WBS libraries inherit its powerful advantages from Java. However, there are cases where explicit specification of models or interface objects is more desirable than the black-box programs. This paper presents an XML-based DEVS (Discrete Event System Specification) markup language for sharing simulation models on the Web. DEVS provides a system-theoretic formalism for the language while XML supports platform-independent data access. This paper focuses on the design of such a language.

• 한국추진공학회지
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• 제23권5호
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• pp.67-74
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• 2019

본 논문에서는 개방형 사이클 액체로켓엔진의 시동해석을 위해 개발된 해석 코드의 수학적 모델을 제시하였다. 추진제 공급 배관에서의 추진제 충진 과정을 포함하여 엔진을 구성하는 대부분의 요소를 고려하였다. 한국형발사체 시험발사체에 사용된 75톤급 엔진의 시동해석을 수행하였으며, 해석 결과와 실험 결과가 잘 일치함을 보임으로써 시동해석 코드의 타당성을 증명하였다.

• Journal of Positioning, Navigation, and Timing
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• 제4권4호
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• pp.173-180
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• 2015

In this study, an algorithm that detects a spoofing signal for a GPS L1 signal was proposed, and the performance was verified through RF spoofing signal simulation. The proposed algorithm determines the reception of a spoofing signal by detecting a correlation distortion of GPS L1 C/A code caused by the spoofing signal. To detect the correlation distortion, a detection criterion of a spoofing signal was derived from the relationship among the Early, Prompt, and Late tap correlation values of a receiver correlator; and a detection threshold was calculated from the false alarm probability of spoofing signal detection. In this study, an RF spoofing environment was built using the GSS 8000 simulator (Spirent). For the RF spoofing signal generated from the simulator, the RF spoofing environment was verified using the commercial receiver DL-V3 (Novatel Inc.). To verify the performance of the proposed algorithm, the RF signal was stored as IF band data using a USRP signal collector (NI) so that the data could be processed by a CNU software receiver (software defined radio). For the performance of the proposed algorithm, results were obtained using the correlation value of the software receiver, and the performance was verified through the detection of a spoofing signal and the detection time of a spoofing signal.

• International Journal of Aeronautical and Space Sciences
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• 제17권3호
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• pp.442-453
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• 2016

A significant source of vibration in helicopters is the main rotor system, and it is a technical challenge to reduce the vibration in order to ensure the comfort of crew and passengers. Several types of passive devices have been applied to conventional helicopters in order to reduce the vibration. In recent years, helicopter manufacturers have increasingly adopted active vibration control systems (AVCSs) due to their superior performance with lower weight compared with passive devices. AVCSs can also maintain their performance over aircraft configuration and flight condition changes. As part of the development of AVCS software for light civil helicopter (LCH) applications, a test bench is constructed and vibration control tests and simulations are performed in this study. The test bench, which represents the airframe, is excited using a pair of counter rotating force generators (CRFGs) and a multiple input single output (MISO) AVCS that consists of three accelerometer sensors and a pair of CRFGs; a filtered-x least mean square (LMS) algorithm is applied for the vibration reduction. First, the vibration control tests are performed with uniform sensor weights; then, the change in the control performance according to changes in the sensor weight is investigated and compared with the simulation results. It is found that the vibration control performance can be tuned through adjusting the weights of the three sensors, even if only one actuator is used.

• 대기
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• 제17권3호
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• pp.241-253
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• 2007

This paper investigates summer precipitation change in East Asia according to switching surface boundary condition over South Korea and Shantung. Simulations are carried out by ECHO-G/S for 20 years (1980-1999). Surface condition over both areas in ECHO-G/S is represented by ocean (OCN experiment). In OCN experiment, the summer precipitation is considerably underestimated around the Korean peninsula (the dry region) and overestimated over the eastern Tibetan Plateau (the wet region). It may be related that the lack of the heat sources from the unrealistically prescribed land-sea mask weakens northward expansion of rainband and the development of convective precipitation. Moreover the simulated rainband retreats before June in connection with the early genesis of summer monsoon circulation. The systematic bias of the summer precipitation over the dry and wet regions are reduced comparing with the OCN experiment when the land-sea masks over South Korea and Shantung are realistically considered as land (LND experiment). These improvements can be explained by the thermodynamical dissimilarity between land and ocean. Enhanced warming by switching the areas from sea to land has led to develop the thermal low over Yellow Sea with the cyclonic circulation. Thus, this cyclonic circulation supports moistures from the south to the dry region and blocks to the wet region. The heat transport from the land surface to atmosphere plays a key role in the developing convective precipitation in local scale and maintaining the precipitation and the rainband. Therefore, this results indicate that the design of the realistic land-sea distribution is required for the accurate simulation of the regional precipitation.