• Transactions of the Korean Society of Automotive Engineers
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• v.20 no.3
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• pp.52-57
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• 2012

Proper door effort is required for the safety of passenger and pedestrian while securing door operating convenience. 3D finite element analyses for a hybrid door checker were carried out to estimate door checker arm resistance force. And, from the estimated door checker arm resistance force and theoretically calculated self-closing force, door effort was predicted. The analysis results at checker arm peaks showed excellent correlation with the test results. Also, in order to reduce solving time, a modified model with simple spring element was investigated. Finally an equation to easily calculate checker arm resistance force from checker arm shape and spring constant was suggested and its usefulness in early design stage was discussed.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.11 no.3
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• pp.86-91
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• 2012

Door effort was calculated for a new door checker with torsion bar spring and integrated checker case by FE analysis. A hybrid checker arm which has peaks and valleys only on the upper surface was adopted to reduce noise in operation and make operation with more distinctive steps. The checker arm was modeled using shell elements to estimate both the longitudinal and the lateral resistance force by checker arm. By combining the checker arm resistance force obtained from analysis and the door self-closing force by the theoretical calculation, door effort was predicted to show the good correlation with test results. In addition the unrolling effect of roller model was investigated and a new roller type for more smooth rolling was studied.

• Transactions of the Korean Society of Automotive Engineers
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• v.11 no.3
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• pp.131-137
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• 2003

Proper door effort, required force to open or close a vehicle door, is an essential door design factor for the safety of passengers and pedestrians. Section shape of the door checker arm is the most influential design parameter for achieving a door effort design target. In this research. an analysis procedure to predict door effort using a simplified plane strain finite element model wes investigated for two passenger cars, for which mechanism of checker systems were: different. The variation of checker arm force to be required during moving on arm in opening and closing direction was estimated through analysis, and the result was transformed to the door effort with respect to door opening angle by considering door characteristics. Also, the self·closing force due to door weight was theoretically calculated and added to the door effort from checker arm force. Finally the estimated results of door effort were compared with test results.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2009.06a
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• pp.831-832
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• 2009

• JSTS:Journal of Semiconductor Technology and Science
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• v.2 no.2
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• pp.132-140
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• 2002

This paper presents an ARM-based SOC bus transaction verification IP and the usage experiences in SOC designs. The verification IP is an AMBA AHB protocol checker, which captures legal AHB transactions in FSM-style signal sequence checking routines. This checker can be considered as a reusable verification IP since it does not change unless the bus protocol changes. Our AHB protocol checker is designed to be scalable to any number of AHB masters and reusable for various AMBA-based SOC designs. The keys to the scalability and the reusability are Object-Oriented Programming (OOP), virtual port, and bind operation. This paper describes how OOP, virtual port, and bind features are used to implement AHB protocol checker. Using the AHB protocol checker, an AHB simulation monitor is constructed. The monitor checks the legal bus arbitration and detects the first cycle of an AHB transaction. Then it calls AHB protocol checker to check the expected AHB signal sequences. We integrate the AHB bus monitor into Verilog simulation environment to replace time-consuming visual waveform inspection, and it allows us to find design bugs quickly. This paper also discusses AMBA AHB bus transaction coverage metrics and AHB transaction coverage analysis. Test programs for five AHB masters of an SOC, four channel DMAs and a host interface unit are executed and transaction coverage for DMA verification is collected during simulation. These coverage results can be used to determine the weak point of test programs in terms of the number of bus transactions occurred and guide to improve the quality of the test programs. Also, the coverage results can be used to obtain bus utilization statistics since the bus cycles occupied by each AHB master can be obtained.

• Transactions of the Korean Society of Automotive Engineers
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• v.23 no.4
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• pp.396-401
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• 2015

A door checker holds a car door at several opening angles and limits the maximum door opening, so that the door does not bump against to passengers. Recently, the performance of door checker becomes more important as the feeling of door opening and closing effects on the quality of a car. However, some of door checkers make squealing noise when they are used for ages, which causes consumer's complaints as well as decreasing commercial value of the product. In this study, after various experiments for the noise, we concluded that the major reasons of the noise are acceleration of wearing and loss of lubricant due to impurities in working parts. Therefore, we developed a new mechanism of door checker which can resolve the major reasons of the noise. The developed mechanism is effective to prevent inflow of impurities and loss of lubricant by locating working parts in the case. We also proved that the developed mechanism does not make any noise after the test of 50,000 times of operations.

• Computational Structural Engineering : An International Journal
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• v.1 no.2
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• pp.89-96
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• 2001

A study on the topology optimization of a Hard-Disk-Driver(HDD) actuator arm is presented. The purpose of the present wert is to increase the natural frequency of tole first lateral mode of the HDD actuator arm under the constraint of total moment of inertia, so as to facilitate the position control of the high speed actuator arm. The first lateral mode is an important factor in the position control process. Thus the topology optimization for 2-D model of the HDD actuator arm is considered. A new objective function corresponding to multieigenvalue optimization is suggested to improve the solution of the eigenvalue optimization problem. The material density of the structure is treated as the design variable and the intermediate density is penalized. The effects of different element types and material property functions on the final topology are studied. When the problem is discretized using 8-node element of a uniform density, tole smoothly-varying density field is obtained without checker-board patterns incurred. AS a result of 7he study, an improved design of the HDD actuator arm is suggested. Dynamic characteristics of the suggested design are compared computationally with those of the old design. With the same amount of the moment of inertia, the natural frequency of the first lateral mode of the suggested design is subsequently increased over the existing one.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.7 s.178
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• pp.1801-1809
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• 2000

A study on the topology optimization of Hard-Disk-Driver(HDD) actuator arm in free vibration is presented. The purpose of this research is to increasse the natural frequency of the first lateral mode of the HDD actuator arm under the constraint of total moment of inertia, so as to facilitate the position control of high speed actuator am. The first lateral mode is an important factor in the position control process. Thus the topology optimization for 2-D model of the HDD actuator arm is considered. A new objective function corresponding to multieigenvalue optimization is suggested to improve the solution of the eigenvalue optimization problem. The material density of the structure is treated as the design variable and the intermediate density is penalized. The effects of different element types and material property functions on the final topology are studied. When the problem is discretized using 8-node element of a uniform density, the smoothly-varying density field is obtained without checker-board patterns incurred. As a result of the study an improved design of the HDD actuator arm is suggested. Dynamic characteristics of the suggested design are compared computationally with those of the old design. With the same amount of the moment of inertia, the natural frequency of the first lateral mode or the suggested design is subsequently increased over the existing one.

• Proceedings of the Korean Information Science Society Conference
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• 2004.10a
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• pp.553-555
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• 2004

SoC 분야에서 온 칩 버스는 전체 시스템의 성능을 결정하는 중요한 요소이다. 이에 따라 최근 ARM 사에서는 고성능 온 칩 버스 구조인 ML(Multi-Layer) AHB 버스를 제안하였다. ML AHB 버스는 저전력 임베디드 시스템에 적합한 버스 구조로써 현재 널리 사용되고 있다. 하지만, 고가이기 때문에 ADK(AMBA$^{TM}$ Design kit) 구매에 대한 부담이 적지 않다. 본 논문은 ML AHB의 버스 구조인 버스 매트릭스 구현 및 ADK에서 제공되지 않는 테스트 환경 즉, Protocol Checker 및 Performance Monitor Module 구현에 관한 것이다.