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채널 결합 기반 대용량 방송서비스를 위한 유효 대역폭 추정 알고리즘에 대한 연구
용기택(Kitak Yong),신현철(Hyunchul shin),이동열(Dongyul Lee),유웅식(Woongsik You),최동준(Dongjoon Choi),이채우(Chaewoo Lee) 大韓電子工學會 2012 電子工學會論文誌-TC (Telecommunications) Vol.49 No.3
현재 HFC(Hybrid Fiber Coaxial) 망에서 UHD(Ultra High Definition) 콘텐츠와 같은 대용량 방송콘텐츠 전송을 위한 대표적인 전송기술로, 다수의 채널을 결합시켜 논리적인 하나의 광대역 채널로 변경하여 데이터를 병렬 전송하는 방법이 대두되고있다. 하지만 채널 결합을 통해 콘텐츠를 전송하는 시스템의 경우 하나의 콘텐츠 전송을 위해서 다수의 채널을 결합하기 때문에 채널 자원의 부족이 예상된다. 따라서 결합된 채널을 효율적으로 사용할 수 있는 기술이 필요하다. 본 논문에서는 결합된 채널의 효율적인 대역폭 사용을 위하여 세 가지 방식의 VBR(Variable Bit Rate) 대역폭 추정 알고리즘을 분석하였다. 세 가지의 유효 대역폭 추정 방식은 Guerin이 제안한 가우시안 근사를 통한 유효 대역폭 추정, Lee가 제안한 비디오 프레임 특성을 기반으로 한 유효 대역폭 추정과 Nagarajan이 제안한 가우시안 트래픽을 기반으로 한 유효 대역폭 추정 알고리즘이다. 또한, 이들을 분석하여 대용량 방송 시스템으로의 적용가능성을 평가하였다. 성능 분석을 위한 시뮬레이션은 OPNET 시뮬레이터를 사용하였고, 성능 분석의 정확성을 위해 실제 HD 방송 트래픽을 분석하여 대용량 방송 트래픽을 생성하였다. A parallel transmitting system with channel bonding method have been proposed to transmit mass content such as UHD(Ultra High Definition) in HFC(Hybrid Fiber Coaxial) networks. However, this system may lead to channel resource problem because the system needs many channels to transmit mass content. In this paper, we analyze three effective bandwidth approximation algorithms to use the bonding channel efficiently. These algorithms are the effective bandwidth of Gaussian approximation method algorithm proposed by Guerin, the effective bandwidth based on statistics of video frames proposed by Lee and the effective bandwidth based on Gaussian traffic proposed by Nagarajan. We also evaluate compatibility of algorithms to the mass broadcasting service. OPNET simulator is used to evaluate the performance of the algorithms. For accuracy of simulation, we make mass source from real HD broadcasting stream.
이동열(Dongyul Lee),김송정(Songjung Kim),임현준(Hyunjune Yim) 한국자동차공학회 2005 한국자동차공학회 Symposium Vol.- No.-
All manufactured parts and tooling have unavoidable variations from their nominal shapes. During assembly, compliant parts are further deformed by relatively rigid assembly tooling. Lack of Knowledge regarding variations and deformations often results in expensive problems. Most current computer-aided design systems are based on ideally sized, ideally located and rigid geometry. This paper proposes a model for the assembly of compliant, non-ideal part. We start by defining tolerance analysis as the process simulation which is the variation of a product or a subassembly when given the tolerance of required parts. Analysis is then done by finite element analysis and using the material properties of the actual parts to be assembled. Using the result, the weld process is estimated.
점용접 되는 변형체의 오차 시뮬레이션을 통한 효과적인 용접 공정 설계
이동열(Dongyul Lee),소현철(Hunchul So),임현준(Hyunjune Yim) 한국자동차공학회 2005 한국자동차공학회 춘 추계 학술대회 논문집 Vol.2005 No.11_3
All manufactured parts and tooling have unavoidable variations from their nominal shapes. During assembly. compliant parts are further deformed by relatively rigid assembly tooling. Lack of Knowledge regarding variations and deformations often results in expensive problems. Most current computer-aided design systems are based on ideally sized, ideally located and rigid geometry. This paper proposes a model for the assembly of compliant, non-ideal part. We start by defining tolerance analysis as the process simulation which is the variation of a product or a subassembly when given the tolerance of required parts. Analysis is then done by finite element analysis and using the material properties of the actual parts to be assembled. Using the result. the weld process is estimated.
이동열(Dongyul Lee),이재열(Jaeyeol Lee),김국생(Kuksaeng Kim),임현준(Hyunjune Yim),이규봉(Gyu Bong Lee) 한국자동차공학회 2003 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
A methodology of analyzing dimensional variations of a subassembly has been developed. considering the effects of weld distortion and weld sequence. As an example, the tailgate of a sports utility vehicle has been considered. A complete thermo-elasto-plastic<br/> finite element analysis has been conducted to find the weld distortion. Using the results.<br/> tolerance analyses have been conducted to find the effects of different weld sequences. Variances of the measured dimensions on the subassembly have been found to be affected by the weld sequence. in spite of the small magnitudes of weld distortion.
Full-system Emulator를 활용한 모바일 향 시스템의 메모리 접근 분석도구 및 응용
이동열(DongYul Lee),이승우(Seungwoo Lee),손영훈(Young Hoon Son),안정호(Jung Ho Ahn) 한국정보과학회 2013 정보과학회논문지 : 시스템 및 이론 Vol.40 No.2
컴퓨터 시스템의 성능을 결정함에 있어 메모리는 중요한 비중을 차지한다. 따라서 메모리 성능 분석에 활용할 수 있는 다양한 시뮬레이션 기법과 도구들이 존재한다. 메모리에 대한 성능을 측정하는 시뮬레이션 도구는 다수 존재하지만, 메모리의 성능을 개선시키기 위한 경향성을 분석하기 위한 수단은 제한적이다. 특히 모바일향 시스템에 널리 사용되고 있는 ARM instruction set architecture를 지원하는 fullsystem simulator는 학계에서도 gem5만이 개방되어 있어 연구를 위한 도구가 한정적이다. 본 논문에서는 ARM 아키텍처의 명령어로 구성된 프로그램을 호스트 컴퓨터에서 동작시킬 수 있는 full-system emulator와 functional simulator를 결합하여 모바일향 시스템의 메모리를 분석할 수 있는 도구를 제안한다. 메모리 분석도구의 검증을 위해 SPEC CPU2006 Integer 벤치마크를 이용하여 실험을 실시하고, 호스트 컴퓨터의 ISA로 구성된 프로그램을 실행시키는 Pin을 활용한 시뮬레이션 결과와 비교 검증하였다. 제안된 분석도구는 특정 응용프로그램 뿐 아니라 시스템 전체의 메모리 접근 경향성을 파악할 수 있으며 기존의 시뮬레이션 기반 도구에 비해 수행속도가 두 배 이상 향상되었다. 또한 모바일향 플랫폼에 널리 사용되고 있는 안드로이드에 대한 실험을 진행하여 제안한 메모리 분석도구를 활용하여 메모리 접근특징을 분석하였다. A memory system is a critical component that determines the entire performance of a computer system. There have been many proposals and implementations designed to be utilized for the performance analysis of memory systems. However, mobile systems are often analyzed and developed under a cross-platform environment, leading to fewer options to perform the memory-system analysis with. This paper proposes a memory-system analysis tool that combines a full-system emulator and a functional simulator to analyze the memory access behaviors of mobile systems that utilize the ARM instruction set architecture. We assess its applicability by conducting experiments that compare its results of the access behaviors extracted by a dynamic instrumentation tool called Pin using SPEC CPU2006 Integer benchmark programs. The proposed tool is capable of analyzing the application- and system-level memory access behaviors, while its analysis performance is more than twice faster than a state-of-the- art full-system simulator.
이동열(Dongyul Lee),이재열(Jeayeol Lee),임현준(Hyunjune Yim),지해성(Haesung Jee) 한국자동차공학회 2004 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
A general methodology for analyzing dimensional variations of subassembly has been developed, considering the effects of weld distortion. As an example, two plates of a fillet welded have been considered. A complete thermo-elasto-plastic finite element analysis has been conducted of find the weld distortion. Using the results, tolerance analyses have been conducted find the effects of weld distortion. Variances of the measured dimensions on the subassembly have been found to be effected weld distortion.
이동열(Dongyul Lee),김송정(Songjung Kim),임현준(Hyunjune Yim) 대한기계학회 2005 대한기계학회 춘추학술대회 Vol.2005 No.11
All manufactured parts and tooling have unavoidable variations from their nominal shapes. During assembly, compliant parts are further deformed by relatively rigid assembly tooling. Lack of Knowledge regarding variations and deformations often results in expensive problems. Most current computer-aided design systems are based on ideally sized, ideally located and rigid geometry. This paper proposes a model for the assembly of compliant, non-ideal part. We start by defining tolerance analysis as the process simulation which is the variation of a product or a subassembly when given the tolerance of required parts. Analysis is then done by finite element analysis and using the material properties of the actual parts to be assembled. Using the result, the weld process is estimated.
임현준,이동열,이재열,권기억,신종계,Yim Hyunjune,Lee Dongyul,Lee Jaeyeol,Kwon Ki Eak,Shin Jong-Gye 대한기계학회 2005 大韓機械學會論文集A Vol.29 No.10
A general and efficient methodology has been developed to analyze dimensional variations of an assembly, taking into account of weld distortion. Weld distortion is generally probabilistic because of the random nature of welding parameters such as the welding speed, maximum welding temperature, ambient temperature, etc. The methodology is illustrated through a very simple example of two perpendicular plates fillet-welded to each other. Two steps comprise the methodology: establishment of a weld-distortion database, and tolerance analysis using the database. To establish the database, thermo-elasto-plastic finite element analyses are conducted to compute the weld distortion for all combinations of discrete values of major welding parameters. In the second step of tolerance analysis, the weld distortion retrieved from the database is used in addition to the dimensional tolerances of the parts. As a result of such an analysis, sensitivities of the assembly's dimensional variations to the part tolerances and weld distortion are obtained, which can be help improve the dimensional quality of the assembly.