• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.49 no.7
• /
• pp.557-564
• /
• 2021

This paper describes an automatic landing approach algorithm for fixed-wing UAVs using waypoint guidance. The proposed algorithm utilizes simple 2D Dubin's vehicle pre-simulations in planning the waypoints for landing approach. The remaining time to reach the runway is also estimated in the pre-simulation, and it is used for altitude control. The performance of the designed algorithm was verified by simulations and flight tests.

• Journal of Digital Convergence
• /
• v.18 no.8
• /
• pp.271-279
• /
• 2020

Simulation practice training is used in nursing education as an education method to improve the adaptability to the clinical field, but responds to unpredictable situations and negatively affects practice satisfaction. This study applied a team-based learning utilizing a pre-briefing inequality controls ago to investigate the effect of self-efficacy, simulation practice satisfaction and clinical performance of the nursing college in the simulation based nursing education and after quasi-experimental study. Data collection in the fourth grade and P University Nursing 72 peoples, the study period is from November 15 from October 14, 2019. As a result, the experimental group that applied team-based learning using pre-briefing showed higher self-efficacy, simulation practice satisfaction, and clinical performance than the control group. Therefore, applying team-based learning to the pre-briefing process can be an important learning strategy for simulation practice training, and suggests a follow-up study to confirm the effectiveness by standardizing the pre-briefing step later.

• Journal of Korea Entertainment Industry Association
• /
• v.14 no.7
• /
• pp.421-427
• /
• 2020

The aim of this study was to examine the impacts of pre-briefing using structured video simulations in the pre-hospital trauma care simulation-based education on simulation immersion, simulation confidence, and simulation satisfaction. For both the experimental group and the control group, orientations were conducted on the simulation environment. Subsequently, the experimental group watched a video of about 8 minutes, similar to the scenario situation, in which the goal and result of the training were presented. The control group, on the other hand, conducted a classical way of orientation related to the scenario during the same time period. In addition, the experimental group and the control group underwent simulation practice in the same situation for 12 minutes, and debriefing was performed for 40 minutes by the same research assistant. Afterwards, we measured the simulation immersion, confidence, and satisfaction of the participants. Data were analyzed using χ² and independent t-test using the SPSS 22.0 program. It was found that the experimental group that conducted the pre-briefing using video had higher immersion and confidence than the control group. On the other hand, satisfaction was not significantly different between the two groups. The results indicate that pre-briefing using structured video was an effective educational method to increase simulation immersion and simulation confidence.

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.41 no.2
• /
• pp.9-18
• /
• 2004

OFDM is a special case of multicarrier transmission, where a high-rate datastream is transmitted over a number of lower rate subcarriers. In this paper, the structure of ORM system is studied, and causes of inter carrier interference (ICI) are analyzed. Based on analysis, this paper shows a technique to prevent a distortion due to nonlinearity of high power amplifier. The proposed scheme is a predistorter(PD) for high power amplifier linearization in OFDM system. This is verified by comparing BER characteristics of OFDM system, between used PD and not used PD, and superiority is shown by comparing BER characteristics of OFDM system, between used the proposed PD and used some other PDs.

• Journal of the Korea Society for Simulation
• /
• v.20 no.3
• /
• pp.89-100
• /
• 2011

The MAGLEV (Magnetically Levitated Vehicle) system, which is under commercialization as a new transportation system in Korea, is operated by means of unmanned automatic control system. Therefore the plan of train operation should be carefully established and validated in advance. In general, when making the train operation plan, the statistically predicted traffic data is used. However, traffic wave can occur when real train service is operated, and the demand-driven simulation technology is required to review train operation plans and service qualities considering traffic wave. This paper presents a method and model to simulate the MAGLEV's operation considering continuous demand changes. For this purpose, we employed the discrete event model which is suitable for modeling the behavior of railway passenger transportation, and modeled the system hierarchically using DEVS (Discrete Event System Specification) formalism. In addition, through the implementation and experiment using DEVSim++ simulation environment, we tested the feasibility of the proposed model and it is also verified that our demand-driven simulation technology could be used for the prior review of the train operation plans and strategies.

• Proceedings of the Korea Society for Simulation Conference
• /
• 1998.10a
• /
• pp.66-70
• /
• 1998

제조환경 정보의 급속한 변화는 변화에 유연(flexible)하게 대처할 수 있는 제조관리 시스템 개발을 요구하게 되었으며 이를 위한 방법으로 객체지향 개발방법론을 이용한 제조관리 시스템이 구축되어 시스템 구성요소들의 재사용성, 확장성, 유연성을 높일 수 있게 되었다. 그러나 개발된 객체지향 제조관리 시스템은 과거 데이터와 불확실한 데이터를 바탕으로 개발된 시스템이므로 시스템의 타당성 및 효율성의 검증을 위한 방법으로 객체지향 시뮬레이터를 개발하였다. 객체지향 시뮬레이터는 개발된 제조관리 시스템이 현장에 구축되었을 때 발생될 수 있는 문제점을 사전에 검출할 수 있을 뿐만 아니라 시스템의 성능을 사전에 측정할 수 있어 제조관리 시스템의 개발비용을 단축할 수 있게 된다. 본 연구에서는 가상공장의 특성을 구현한 가상공장(virtual factory) 콤포넌트, 제조관리 시스템과의 인터페이스를 담당하는 커넥터(connector) 콤포넌트, 제조시스템의 구성환경을 모델링하는 컨피규레이션(configuration) 콤포넌트, 시뮬레이션의 시간전진을 담당하는 시계(clock) 콤포넌트 등으로 이루어진 객체지향 시뮬레이션의 프레임워크(framework)를 제시하고, 제조관리 시스템과 연계된 시뮬레이션을 통해 제조관리 시스템의 검증, 평가 방안으로 이용하였다.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.4 no.4
• /
• pp.329-333
• /
• 2003

In this paper we analyze the performance of the low latency pre-registration handoff method of mobile IP by computer simulation. Packet losses and delays are evaluated in terms of system utilization. Foreign agents that participate in the handoff process can be modeled as queues representing input and output ports. Therefore, we propose an analytical model of pre-registration handoff by using open queueing network model. Simulation results are shown for validating analytical estimates.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.12 no.3
• /
• pp.427-432
• /
• 2017

This study describes the design and implementation of SHF band Downconverter Digital Satellite Communication. The SHF band Downconverter unit consists of PLDRO and Frequency converter. In Frequency converter, microstrip BPF and LPF designed through the pre EM simulation are implemented to minimize the unwanted spurious in Frequency converter. Through the pre-simulation analysis of space environment, the possibility of and minimized about the malfunction of equipment and we designed a reliable SHF band Downconverter through simulation for a TID according to the vibration generated during the launch and space radiation environment, and compared pre-simulation of main performance results to test results about main performances of SHF band Downconverter after production.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.12 no.2
• /
• pp.261-266
• /
• 2017

This study describes the design and implementation of SHF band Upconverter Digital Satellite Communication. The SHF band Upconverter unit consists of PLDROand frequency converter. In frequency converter, microstripBPF and LPF designed through the pre EMsimulation are implemented to minimize the unwanted spurious in frequency converter. Through the pre-simulation analysis ofspace environment, the possibility of and minimized about the malfunction of equipment and we designed a reliable SHF band Upconverter through simulation for a TID according to the vibration generated during the launch and space radiation environment, and compared pre-simulation of main performance results to test results about main performances of SHF band Upconverter after production.

• Proceedings of the Korea Society for Simulation Conference
• /
• 1992.09a
• /
• pp.217-218
• /
• 1992

S사는 생산량 증대에 따른 물동량 증가에 대비하기 위하여 물류 시스템 개선안을 수립한 수 , 타다성을 검증하기 위해 시뮬레이션 기법을 채택하여 물류관점에서 현행 시스템 및 개선안에 대한 진단을 실시하였다. 컴퓨터 시뮬레이션 기법은 생산공정에 실질적인 물리적 변화를 가하지 않고도 "What-if" 라는 다양한 시나리오를 작성하고 이들에 대한 분석 및 평가를 통하여 그 가능성을 타진하며 최적안을 도출하는데 유용하게 이용되는 도구이다. 본 진단을 통하여 현행 시스템의 문제점을 정량적으로 파악하였다. 그리고, 물류 개선안에 대한 기대효과를 예측하고 발생가능한 문제점을 사전에 도출하여 시행착오를 최소화하는데 기여하고자 하였다.기여하고자 하였다.