• 한국항공우주학회지
• /
• 제44권6호
• /
• pp.530-536
• /
• 2016

고-신뢰도 모델을 이용한 조종성 평가 시뮬레이션 환경은 비행제어시스템의 설계/평가에 필수적으로 요구된다. 한국항공우주산업(주)에서는 소형민수헬기 핵심기술 개발과 관련하여 자동비행조종장치 소프트웨어 개발과제를 수행 중에 있으며 제어법칙 설계를 위한 비행동역학 모델 및 해석을 위해 상용 도구인 FLIGHTLAB을 이용하고 있다. 본 연구에서는 기존에 개발된 레거시 시뮬레이터를 FLIGHTLAB 모델과 연동하고 이를 조종성 평가에 활용한 내용을 다루었다. 본 논문에서는 외부 연동을 위한 FLIGHTLAB 모델의 설정, 연동 프로그램 개발 및 연동 방안에 대한 내용을 수록하였다. 또한 본 논문에서는 레거시 시뮬레이터와의 연동을 통해 ADS-33E-PRF의 호버 및 pirouette MTE 기동비행을 수행하고 평가 결과를 수록하였다.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2007년도 제38회 하계학술대회
• /
• pp.584-585
• /
• 2007

In this paper describe the block simulator that simulate generator's contoler such as governor, exciter and stabilizer. To use legacy tool such as PSS/E for user defined model is very difficult. The simulation tool such as Matlab/Simulink is easy to simulate user defined model but integrate simulation and power system network analysis is unavailable. As a result this paper show that block simulator for contoler model verify. It is include block simulator design, implementation and verify to Matlab/Simulink.

• 경영과학
• /
• 제26권2호
• /
• pp.37-59
• /
• 2009

Electronic brainstorming (EBS) to improve the process and outcomes of group decision making is an artifact of Information Systems legacy. Despite three decades of research with EBS in an effort to become a key resource of organizational performance, its performance when compared to that of nominal is inconclusive because of the recent debate over its usefulness in terms of productivity. Subsequent researchers have directed our attention to the re-examination of cognitive stimulation, which is considered the major benefit in computer-based idea generation, to explain the performance singularity in computer-based groups. While both cognitive and motivational factors that moderate and mediate the group-interaction process remain unexplored, individual differences that are tightly linked to creative behavior have been largely ignored to account for the discrepancy in performance. Since simulations have been widely used in situations where an outcome does not meet the assumptions, the notion of a group simulator and detailed simulation mechanisms are introduced to examine the potential effects of individual differences on the performance of computer-based idea generation groups. In addition, two prior studies that empirically explored cognitive mechanisms with the group simulator are showcased along with six propositions to initiate future research.

• 한국정보컨버전스학회:학술대회논문집
• /
• 한국정보컨버전스학회 2008년도 International conference on information convergence
• /
• pp.199-204
• /
• 2008

Sensor nodes have various energy and computational constraints because of their inexpensive nature and ad-hoc method of deployment. Considerable research has been focused at overcoming these deficiencies through faster media accessing, more energy efficient routing, localization algorithms and system design. Our research attempts to provide a method of improvement MAC performance in these issues. We show that traditional carrier-sense multiple access(CSMA) protocols like IEEE 802.11 do not handle the first constraint adequately, and do not take advantage of the second property, leading to degraded latency and throughput as the network scales in size, We present more efficient method of a medium access for real-time wireless sensor networks. Proposed MAC protocol is a randomized CSMA protocol, but unlike previous legacy protocols, does not use a time-varying contention window from which a node randomly picks a transmission slot. To reduce the latency for the delivery of event reports, it carefully decides a fixed-size contention window, non-uniform probability distribution of transmitting in each slot within the window. We show that it can offer up to several times latency reduction compared to legacy of IEEE 802.11 as the size of the sensor network scales up to 256 nodes using widely used simulator ns-2. We, finally show that proposed MAC scheme comes close to meeting bounds on the best latency achievable by a decentralized CSMA-based MAC protocol for real-time wireless sensor networks which is sensitive to latency.

• 한국항해항만학회지
• /
• 제35권3호
• /
• pp.187-195
• /
• 2011

선박운항자의 인적사고 방지 및 운항 훈련을 위한 방안으로 선박 운항 시뮬레이터가 사용된다. 선박운항 시뮬레이터에서 실시간 3D 가시화 기술은 현실감 있는 직관적인 영상을 제공하여 피교육자에 인지력을 향상시켜 시뮬레이터의 교육 효과를 높이는 중요한 요소이다. 본 연구에서는 공개형 3D 그래픽 엔진을 기반으로 선박 운항 시뮬레이터용 실시간 3D 가시화 시스템을 설계하고 구현한 결과에 대해서 설명한다. 실시간 3D 가시화 시스템은 요소 기능, 기존 그래픽 데이터 활용, 타 시스템과의 연동 측면에서 도출된 운용 요구사항들을 만족하며 추가적인 기능의 확장이 용이한 구조로 설계되었다.

• 한국인터넷방송통신학회논문지
• /
• 제20권4호
• /
• pp.87-92
• /
• 2020

GPGPU(General-Purpose GPU)는 수만 단위의 스레드들을 병렬적으로 수행하여 성능을 최대화시킬 수 있지만, 실질적으로는 스레드들을 그룹화하여 스레드블록(Thread Block) 단위로 작업을 정의하고 GPGPU 하드웨어 자원의 할당 단위로 활용한다. 이러한 역할을 담당하는 스레드블록 스케줄러는 GPGPU내에 하드웨어적으로 구현되어 있으며, 스레드블록들을 하드웨어 자원들에게 라운드로빈 방식으로 할당한다. 그런데, 라운드로빈 정책은 단순 순차 할당 방식으로서 GPGPU 하드웨어 자원의 활용도에 최적화되어 있지 않다. 본 논문에서는 다양한 스레드블록 스케줄링 방식의 성능을 정량적으로 분석할 수 있는 스레드블록 스케줄러 모델을 제안하고, 구현된 시뮬레이터의 성능 결과를 통해 기존 GPGPU의 스레드블록 스케줄링 방식이 작업 부하가 높은 경우에는 적합하지 않음을 보이고자 한다.

• Journal of Positioning, Navigation, and Timing
• /
• 제8권4호
• /
• pp.139-152
• /
• 2019

The design of new navigation signals is a key factor in building new satellite navigation systems and/or modernizing existing legacy systems. Navigation signal design involves selecting candidate groups and evaluating and analyzing their signal performances. This process can be easily performed through software simulation especially at the beginning of the development phase. The analytical signal performance analysis software introduced in this study is implemented based on equations between the signal design parameters of Radio Navigation Satellite Service (RNSS) and the navigation signal figures-of-merit (FoMs). Therefore, this study briefly summarizes the RNSS signal design parameters and FoMs before introducing the developed software. After that, we explain the operating sequence of the implemented software including the Graphical User Interface (GUI), and calculate the FoMs of an example scenario to verify the feasibility of the software operations.

• Journal of information and communication convergence engineering
• /
• 제4권4호
• /
• pp.141-146
• /
• 2006

In these days, wireless data services are becoming ubiquitous in our daily life because they offers several fundamental benefits including user mobility, rapid installation, flexibility, and scalability. Moreover, the requests for various multimedia services and the Quality of Service (QoS) support have been one of key issues in wireless data communications. Therefore the research relative to Medium Access Control (MAC) has been progressing rapidly. Especially a number of QoS-aware MAC schemes have been introduced to extend the legacy IEEE 802.11 MAC protocol which has not guaranteed any service differentiation. However, none of those schemes fulfill both QoS features and channel efficiency although these support the service differentiation based on priority. Therefore this paper studies a novel MAC scheme, referred to as Enhanced Distributed Coordination Function with Network Adaptation (EDCF-NA), for enhancements of both QoS and medium efficiency. It uses a smart factor denoted by ACK rate and Network Load Threshold (TH). In this paper, we study how the value of TH has effect on MAC performance and how the use of optimal TH pair improves the overall MAC performance in terms of the QoS, channel utilization, collision rate, and fairness. In addition, we evaluate and compare both the performance of EDCF-NA depending on several pairs of TH and the achievement of various MAC protocols through simulations by using Network Simulator-2 (NS-2).

• 한국콘텐츠학회:학술대회논문집
• /
• 한국콘텐츠학회 2007년도 추계 종합학술대회 논문집
• /
• pp.611-614
• /
• 2007

IEEE 802.11e의 EDCF(Enhanced Distributed Coordination Function)는 무선 랜에서의 QoS(Quality of Service)를 지원하기 위해 표준화되었다. EDCF는 경쟁 기반 채널 접근 방식으로 기존의 DCF(Distributed Coordination Function)를 강화한 매체 접근 프로토콜로서 차별화된 AC(Access Category)를 가지고 있다. 본 논문에서는 IEEE 802.11e 네트워크에서 QoS에 영향을 미치는 파라미터인 AIFS(Arbitration Inter Frame Space), CWmax(Max Contention Window) 값을 변화함으로써 각 파라미터가 네트워크 성능에 미치는 영향을 평가하였다. 시뮬레이션 수행은 NS-2 (Network Simulator-2)를 이용하였으며, 성능 파라미터의 변화에 따른 네트워크 성능의 변화를 검증하였다.

• 전기학회논문지
• /
• 제65권5호
• /
• pp.811-818
• /
• 2016

This paper suggests a structure of power control system in floating wave-offshore wind hybrid power generation system. We have developed an unified SCADA(Supervisory Control and Data Acquisition) system which can be used to monitor and control PCS(Power Conversion System) based on IEC61850. The SCADA system is essential to perform the algorithm like proportional distribution and data acquisition, monitoring, active power, reactive power control in hybrid power generation system. IEC61850 is an international standard for electrical substation automation systems. It was made to compensate the limitations of the legacy industrial protocols such as Modbus. In order to test the proposed SCADA system and algorithm, we have developed the wind-wave simulator based Modbus. We have designed a protocol conversion device based on real-time Linux for the communication between Modbus and IEC61850. In this study, SCADA system consists of four 3MW class wind turbines and twenty-four 100kW class wave force generator.