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직교 주파수 분할 다원 접속 시스템에서 실효 링크 계층 용량을 고려한 다중 사용자 자원 할당 기법
성시환,유명식,신요안,이원철,Sung Si-Hwan,Yoo Myung-Sik,Shin Yo-An,Lee Won-Cheol 한국통신학회 2006 韓國通信學會論文誌 Vol.31 No.6B
무선 네트워크 사용자가 폭발적으로 증가하구 서비스 종류들이 다양해짐에 따라 고 전송률 및 사용자의 QoS(Quality of Service) 보장에 대한 요구가 강화되고 있는 현실이다. 본 논문에서는 이를 위한 해결 방안으로 직교 주파수 분할 다원 접속 시스템 상에서 사용자 QoS 요구사항의 만족을 고려한 주파수 자원 할당 기법을 제안한다. 즉, 본 논문에서는 시간 분할 다원 접속 시스템에서 지연에 민감한 사용자의 QoS 만족을 위하여 송신 기지국과 각각의 사용자들 사이의 통계적인 채널 특성과 더불어 사용자마다의 실시간 큐잉 분석을 고려한 M-LWDF(Modified-Largest Weighted Delay First)를 기반 한 자원할당 기반의 RR(Round Robin) 및 K&H(Knopp&Humblet) 결합 스케줄링을 제안하며, 이를 통해 전체적인 시스템의 전송률 향상과 지연에 민감한 서비스를 요구하는 사용자의 QoS를 만족시킬 수 있다는 점을 확인한다. 또한 제안한 기법을 OFDMA (Orthogonal Frequency Division Multiple Access) 시스템에 적용하여 최적의 부 캐리어 할당을 통한 사용자 스케쥴링을 수행한다. 본 논문에서 제안된 기법의 성능을 분석하기 위하여 물리계층의 채널 특성으로부터 구해진 실효 링크 계층 용량을 고려하여 모의실험을 수행하였다. The explosive growth of wireless network users and the existence of various wireless services have demanded high rate throughput as well as user's QoS guarantees. Towards this, this paper proposes QoS-oriented subcarrier allocation scheme considering the QoS provisioning of multiple users, which is major requirement for wireless network design point of view. This paper introduces joint RR/K&H combined with M-LWDF(Modified Largest Weighted Delay First) scheme throughout observing statistical channel behavior and real time queuing analysis for appropriate resource allocation tightly connected to multiuser scheduling. Accordingly, the system throughput can be enhanced, and the QoS demanded for delay sensitive services can be satisfied. Furthermore, the proposed scheme is applied for OFDMA(Orthogonal Frequency Division Multiple Access) systems to allocate sub-carriers in optimal way. The simulation results verify plausible performances of proposed resource allocation scheme via showing superior effective capacity under time-varying physical-layer channel behaviors.
효율적인 비례 제어 솔레노이드 밸브 구동을 위한 이종주파수 펄스폭변조 제어 기법
성시환(Sihwan Sung),최성열(Sungyeol Choi),정현철(Hyuncheol Jung),김동규(Dongkyu Kim),김병곤(Byunggon Kim),정준채(Junchae Jung) 한국자동차공학회 2020 한국 자동차공학회논문집 Vol.28 No.11
Solenoid valve is generally used for controlling the enormous mechanical machine in an automobile. The use of the PWM-driven solenoid has become common due to the inefficiency of driving a solenoid using the traditional on/off method in terms of power usage and solenoid coil burnout. In this paper, we conduct modeling and mathematical analysis in regard to the instantaneous current of the PWM-controlled solenoid valve with slow decay and fast decay. Furthermore, we propose a heterogeneous PWM-controlled scheme, which is considered to be a trade-off of power dissipation, electromagnetic interference, and response time. The simulation results verify the plausible performances of the proposed heterogeneous PWM-controlled scheme by demonstrating the solenoid valve response time via current driven based on the real parameters of the continuous damping control system.
대역 확산 PWM 제어를 통한 CDC 댐퍼 솔레노이드 밸브 구동 시 EMI 성능 개선 연구
성시환(Sihwan Sung),정우진(Woojin Jung),강용진(Yongjin Kang),김병곤(Byunggon Kim),한상수(Sangsu Han) 한국자동차공학회 2017 한국자동차공학회 학술대회 및 전시회 Vol.2017 No.11
As more Electronic Control Units (ECU) are increased in the car, the electromagnetic noise from the many electronic units would be possible to interference to other electronic systems. All of the switching signals such as MCU, DC/DC clock and PWM signal for Motor/Solenoid valve control in ECU can be electromagnetic interference (EMI) noise. In this paper, we propose the CDC Solenoid Valve control scheme using a Spread Spectrum PWM Technique. Spread spectrum is a technique introduced for mitigating EMI problems in many class of circuits. With particular emphasis on solenoid valve control, we consider the most common and most efficient known spreading techniques, looking for spreading parameters that ensure the EMI reduction.
솔레노이드 밸브 전류 응답성 향상을 위한 이종의 PWM 제어 기법
성시환(Sihwan Sung),최성열(Sungyeol Choi),김병곤(Byunggon Kim),정준채(Junchae Jung) 한국자동차공학회 2019 한국자동차공학회 학술대회 및 전시회 Vol.2019 No.11
Generally, Solenoid valve is used to control enormous mechanical machine in automobile. At that time using of PWM driven solenoid has become common due to inefficient to drive a solenoid with traditional on/off method in terms of power usage and solenoid life caused by coil burden. In this paper, we conduct modeling and mathematical analysis in regards to the instant current of PWM controlled solenoid valve with slow decay and fast decay. Also we propose the heterogeneous PWM controlled scheme which is considered trade-off of power-dissipation, electromagnetic-interference and response-time performance. The simulation results verify plausible performances of proposed the heterogeneous PWM controlled scheme via showing response-time by current driven of solenoid valve based on real-parameters of continuous-damping-control system.
Thermal VIA 설계에 따른 PCB 방열 특성 분석
최성열(SeongyeolChoi),성시환(SihwanSung),정현철(DongkyuKim),김동규(DongkyuKim) 한국자동차공학회 2020 한국자동차공학회 학술대회 및 전시회 Vol.2020 No.11
As the development of autonomous vehicle progressed rapidly, more electronic control units are required by in restricted space of car, accordingly this reason why related unit has more complexity than previous structures. For smaller ECUs, various portion need to be reviewed. One of the items to be reviewed is thermal characteristic. This paper intend to direction of thermal design of PCB, based on simulation results of thermal VIA design of components.
하단부 Via Hole 최적화를 통한 IC의 솔더링 및 열 특성 향상에 관한 연구
최성욱(Seongwook Choi),성시환(Sihwan Sung) 한국자동차공학회 2023 한국자동차공학회 학술대회 및 전시회 Vol.2023 No.11
As automobiles become more electronic, the importance of in-vehicle electronic systems is increasing, and the demand for improved performance and enhanced stability of controllers is also increasing. Accordingly, the number of electrical components required for electronic control units (ECUs) is also increasing. This means that understanding and efficient management of electrical components directly affects the performance of automotive electronic systems. In the process of mounting electrical components on a PCB, the via hole specifications of the PCB must be considered in accordance with the soldering and thermal characteristics of the IC. These characteristics affect the functional aspects and heat generation of the IC, which is an important factor in determining the stability and reliability of the system. In this study, we propose a method to improve soldering quality and heat dissipation characteristics by optimizing the specifications of the via hole at the bottom of the IC. It is expected that this measure will contribute to improving the performance and strengthening the stability of automotive electronic systems.