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An Efficient Mode Selection Method of Macroblock in a GOB of H.263 Encoder
Hur,Taewon,Kim,Jeongwoo,Yi,Juneho,Lee,Keunyoung,Kim,Haesoo 성균관대학교 1998 학술회의지원논문목록집 Vol.1998 No.-
This research features efficient made selection of macroblock in a GOB (Group of Blacks) of H.263. We propose a novel method based on the Vitcrbi algorithm that is a minimum-cost search technique. In H.263 standard, mode selection strategics use prediction error or energy of macroblocks and do not consider the amount of biu generated. We consider bath prediction error and the amount of bitsgenerated. We apply a Lagrangian con function ta these strategies. In order to determine the Lagrange multiplier (frame-to-frame multiplier and macroblock-to-macroblock multiplier). we have considered a variety of potential approaches. The instantaneous rate of the encoder is controlled by these values. Experimental results show that PSNR gain of the proposed approach is greater than that of the H.263 test model, TMN5.
차량 서브프레임의 유한요소 모델의 개선 및 최적화에 대한 연구
허덕재(Deogjae Hur),이근수(Keunsoo Lee),홍석윤(Sukyoon Hong),박태원(Taewon Park) 한국자동차공학회 2002 한국 자동차공학회논문집 Vol.10 No.2
This paper describes an integrated approach process to carry out pre-test, model correlation and updating analysis on the sub-frame of a vehicle. In this study, it was found that the modal test could be more efficient when the exciting point was selected on the area with high driving point residue. Such area could be located with the aid of finite element modal analysis. The model correlation was appraised in conjunction with the modal parameters between modal test and finite elements analysis. Also. the finite element model updating was obtained the good resultant using the iteration method based on sensitivity analysis results that carried out the variation of natural frequencies and MAC for the material properties. Finally, optimization of vehicle subframe was carried out the analysis of core location and physical properties by tow steps.
허현무(Hyunmoo Hur),박준혁(Joonhyuk Park),유원희(Wonhee You),박태원(Taewon Park) 대한기계학회 2007 대한기계학회 춘추학술대회 Vol.2007 No.5
The critical speed of railway bogie related to the stability of the railway rolling-stock is important. Testing of the dynamic performance of bogie is conducted using a roller rig in a laboratory in place of field testing on track. This roller rig is composed of two rollers equivalent to track and used to test the dynamic characteristics of vehicle. But, the geometrical characteristics of the wheel/roller contact on the roller rig are different from those of the wheel/rail contact because the longitudinal radius of roller is not infinite compared with rail. This difference has influence on the wheelset behavior and the critical speed of bogie. Therefore in this paper, we have studied the behavior of wheelset and bogie on the roller rig for railway bogie testing with the purpose of developing the scaled roller rig. As an analysis results, it has been shown that the critical speed of bogie on the roller rig is slightly lower than that of bogie on track.
허현무(Hyunmoo Hur),박준혁(Joonhyuk Park),유원희(Wonhee You),박태원(Taewon Park) 대한기계학회 2007 대한기계학회 춘추학술대회 Vol.2007 No.10
The critical speed of railway bogie relating to the stability of the railway rolling-stock is important. The dynamic performance of bogie is tested on the roller rig in a laboratory in place of field testing on track. This roller rig is composed of two rollers equivalent to track and used to test the dynamic characteristics of vehicle. But, the test on the full scale roller rig caused many problems relating to test costs, test time. To overcome these problems, the scale roller rig is used for the convenience of test effectively. But the creep coefficient relating to creep force calculation have an effect on the stability of the scale bogie. In this paper, we have studied the scale model of roller rig and analyzed the stability of the scale bogie according to the creep coefficient calculation.
전동차 차륜 마모에 따른 차륜/레일 기하학적 접촉 특성 변화 분석
허현무(Hyunmoo Hur),박준혁(Joonhyuk Park),유원희(Wonhee You),박태원(Taewon Park) 대한기계학회 2008 대한기계학회 춘추학술대회 Vol.2008 No.11
In a railway vehicle, contact between wheel and rail is a peculiar characteristic and variations of wheel and rail profile influence on the dynamic characteristics of railway vehicle. Thus the variations of the wheel and rail profile are very important in railway dynamics. Recently a research relating to active steering to improve the curving performance of vehicle is progressing actively at home and abroad. In this field, a pre-study for the wheel/rail contact geometry is needed and especially the variation of the wheel/rail contact geometry with wheel wear is the key design parameter to develop the controller of the active steering bogie. In this paper, we have experimentally studied to analyze the variation of the wheel/rail contact geometry with wheel wear as a pre-study to develop the active steering bogie for electric multiple unit (EMU). For this, we have made an experiment with EMU operating in curving area. We have measured the wear profiles of the wheel of the test vehicle and analyzed the wheel/rail contact geometry with a mileage of the test vehicle. In experiment with test vehicle, we have got the useful data to design the steering controller of the wheelset.
Performance Evaluation of CFRP Reinforced Concrete Members Utilizing Fuzzy Technique
Lan Chung,Moo-Won Hur,Taewon Park 한국콘크리트학회 2019 International Journal of Concrete Structures and M Vol.13 No.2
Aging and structural deterioration under severe environments are major causes of damage in reinforced concrete (RC) structures, such as buildings and bridges. Degradations such as concrete cracks, corrosion of steel, and deformation of structural members can significantly degrade the structural performance and safety. Therefore, effective and easy-to-use methods are desired for repairing and strengthening such concrete structures. Various methods for the strengthening and rehabilitation of RC structures have been developed over the past several decades. Recently, FRP composite materials have emerged as a cost-effective alternative to conventional materials for repairing, strengthening, and retrofitting deteriorating/deficient concrete structures, by externally bonding FRP laminates to concrete structural members. The main purpose of this study is to investigate the effectiveness of the FRP retrofit for circular type concrete columns under the framework of the adaptive neuro-fuzzy inference system (ANFIS). Retrofit ratio, strength of existing concrete, thickness, number of layer, stiffness, ultimate strength of fiber, and size of specimens are used as input parameters to predict strength, strain, and stiffness of the post-yielding modulus. These proposed ANFIS models show reliable increased accuracy in predicting the constitutive properties of concrete retrofitted by FRP, compared to the constitutive models suggested by other researchers.