http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
802.16 BWA 시스템에서 UGS 알고리즘의 유휴 대역을 이용한 효율적인 상향링크 알고리즘
이재길(Jaekil Lee),윤희용(Hee Yong Youn) 한국정보과학회 2005 한국정보과학회 학술발표논문집 Vol.32 No.2
무선 통신망은 유선 통신망에 비하여 대역이 한정적이기 때문에 효율적인 대역의 이용은 매우 중요하다. 그러나 802.16 BWA 시스템의 UGS 알고리즘은 보낼 데이터가 없어도 일정한 간격으로 고정 대역을 단말에 계속 할당하기 때문에 대역의 낭비가 심하다. 본 논문에서는 VAD가 가능한 단말에서 UGS 알고리즘을 이용할 때, 보낼 패킷이 없는 경우에는 그 유휴 대역을 이용하여 우선순위가 낮은 nrtPS나, BE 알고리즘을 이용하는 패킷을 대신 전송하는 방법을 제시함으로써, 802.16 BWA 시스템에서 효율적인 상향링크 스케줄링을 구현한다.
순간중심을 이용한 평면 3 자유도 자동차 모델의 롤 운동 해석
이재길(Jaekil Lee),심재경(Jaekyung Shim) 한국자동차공학회 2006 한국 자동차공학회논문집 Vol.14 No.4
In this paper, a planar car model with 3 degrees of freedom was analyzed using the concept of the roll center. To avoid ambiguity, force components which require experimental data were excluded. Only kinematic approach was used to find the position and orientation of the vehicle body and the position of the roll center. The roll center was found by the pole with infinitesimal movement and Kennedy-Aronhold theorem. Centrodes, which are the loci of instantaneous centers of planar motion, were constructed with analyzed results to show characteristics of vehicle body motion. To verify the presented analysis method in this paper, the locus of the roll center and the motion of a 3 D.O.F. planar car model were compared with those of the 1 D.O.F. model.
순간중심을 이용한 평면 3 자유도 자동차 모델의 롤 운동 해석
이재길(Jaekil Lee),심재경(Jaekyung Shim) 한국자동차공학회 2005 한국자동차공학회 춘 추계 학술대회 논문집 Vol.2005 No.11_2
In this paper, a planar car model with 3 degrees of freedom was analyzed using the concept of the roll center. To avoid ambiguity, force components which require experimental data were excluded. Only kinematic approach was used to find the position and orientation of the vehicle body and the position of the roll center. The roll center was found by the pole with infinitesimal movement and Kennedy-Aronhold theorem. Centrodes, which are the loci of instantaneous centers of planar motion, were constructed with analyzed results to show characteristics of vehicle body motion. To verify the presented analysis method in this paper, the locus of the roll center and motion of the 3 D.O.F planar car model were compared with those of the 1 D.O.F model.
이재길(JaeKil Lee),김선평(SeonPyung Kim),오영호(YoungHo Oh) 한국자동차공학회 2010 한국자동차공학회 부문종합 학술대회 Vol.2010 No.5
A new method that can accurately calculate kingpin axes of all suspension types is proposed. Methods using instant axis theory are widely used to determine the kingpin axis of a suspension system. In these methods, since a suspension system has two degrees of freedom, it is commonly used to find a kingpin axis during steer motion by constraining other motion such as bump-rebound motion. Constraining the motion, however, deteriorates the accuracy of the results. In this study, four constraint wrenches that come from suspension links and the definition of a kingpin axis are used to extract the position of the kingpin axis without any extra assumption. To solve four linear equations from wrench axes and one quadratic equation from kingpin axis definition, singular value decomposition method is used. Using numerical examples that consist of McPherson strut, double wishbone, and multi-link suspension systems, accuracy and versatility of the proposed method is shown.
한계 선회 가속시 스티어링 복원성 원리 분석과 보상 로직 개발
이한승(Hanseung Lee),정대석(Daesuk Jung),이재길(Jaekil Lee) 한국자동차공학회 2017 한국자동차공학회 학술대회 및 전시회 Vol.2017 No.11
This paper describes steering returnability by analyzing forces applied to kingpin axis in limit cornering condition. The steering returnability is related to force applied to kingpin axis. These forces could be classified by its source: Tire force and Steering force. The tire force is the force generated from tire such as longitudinal, lateral, vertical force, and self-aligning torque. The steering force consists of friction force and assist force. These forces are vectorized by suspension geometry and calculated with respect to kingpin axis. The simulation results are correlated with measurement data and verifies that steering returnability is formulated by tire forces and steering forces. This study proposes new steering control logic at limit driving condition This logic is verified by simulation model to check performance and confirmed in various test conditions for robustness..
박미란(Miran Park),심재경(Jaekyung Shim),이재길(Jaekil Lee),권진욱(Jin Wook Kwon),임득재(Deukjae Im) 한국자동차공학회 2011 한국자동차공학회 부문종합 학술대회 Vol.2011 No.5
In this paper, the compliance screw axes of multi-link, double wishbone, and McPherson type suspensions are found by using the analytical method using screw theory. The compliance screw axis is obtained by the linear combination of the twist axes which are obtained by releasing the constraint wrench that acts through each link. Static analysis is performed to find the coefficients of the linear combination. The compliance screw axes of the multi-link, double wishbone, and McPherson suspension are compared with the kinematic steering axes of the systems.
김현중(Hyunjoong Kim),심재경(Jaekyung Shim),이재길(Jaekil Lee) 한국자동차공학회 2006 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
In this paper, type synthesis of variable valve lift mechanisms for automotive engines is performed using graph theory. In general, variable valve lift mechanisms can be classified into two groups: The first group is a system consists of two one-degree-of-freedom mechanisms with a switch, and the other group is a mechanism with two degrees of freedom. In this study, graphs of variable valve lift mechanisms in both groups with up to five links and two independent loops are enumerated and some feasible mechanisms are drawn.
SPMD를 이용한 half-car 모델의 롤 운동 해석
박시준(Sijun Park),심재경(Jaekyung Shim),임득재(Deukjae Im),이재길(Jaekil Lee) 한국자동차공학회 2009 한국자동차공학회 학술대회 및 전시회 Vol.2009 No.11
In this paper, I suggest a method of estimate half-car model’s roll capacity using the measured trace of kinematic roll center that is an instant center of velocity from a data of wheel motion, on fixed ground, with SPMD. The trace of roll center found out from proposed method, drew on the coordinate of reference fixed on the surface which called fixed centrode, and the trace of wheel drawn on the moving coordinate reference that fixed on a car body is called moving centrode. These are able to be seized the vehicle’s kinematical roll characteristic except compliance effects by bush of suspension system under the shape of fixed and moving centrodes. We verify availability of this paper with comparison between the roll center when suspension system geometry is given and another roll center using SPMD data which is proposed in this paper. Also, I compare with roll center which is measured from SPMD