• The Transactions of the Korean Institute of Electrical Engineers P
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• v.52 no.2
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• pp.85-90
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• 2003

This paper has presented the efficient implementation of MPEG-4 simple profile video decoder, which is used as video compression standard in mobile video communication. We have used the ARM9 processor in implementing this MPEG-4 simple profile, which requires much processing power and low power implementation. At first we implemented with C-language under the PC environment with ADS(ARM Developer Suite) environment, and then we have tried to reduce a clock cycle for a power consumption optimization through conversion an assembly language for C-code partly. We have verified the processor is operated at 22.47MHz operation after optimization, but 148MHz before optimization.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.47-48
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• 2007

A CMP Process has many factors that affect result of a polished wafer. Dominant factors are velocity, pressure and temperature in process. A pad profile is also considered as affecting factor of CMP. Accoding to variation of a pad profile, the each pan of a wafer is differently pressured. It appears to affect the uniformity of a wafer. A pad profile varies as a swing arm conditioner which have been ordinarily used in industry. A swing arm conditioner has several sectors in its swing path. This study aims that a wafer get a good uniformity as swing arm conditioner's path on pad is analyzed and simulated. Through the simulation, tendency of pad profile after conditioning will be predicted and the result of simulation compared with the result of experiment. The optimized pad profile would be made by to vary swing arm's velocity on each sector. In order to maintain the optimized profile, conditioner design or swing arm's velocity should be changed and designed.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.21 no.11
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• pp.963-967
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• 2008

There are many factors to affect polishing performance normally in chemical mechanical polishing (CMP) process. One of the factors is a pad profile. A pad profile has not been considered as a significant factor. However, a pad profile is easily changed by conditioning process in CMP, and then changed pad profile affects polishing performance. Therefore, understanding how the pad profile is changed by conditioning process is very important. In this paper, through the simulation based on kinematic analysis, the variation of the pad profile was described in accordance with difference condition of conditioning process. A swing-arm type conditioner was applied in this simulation. A swing-arm type conditioner plays a role of generating asperities on pad surface. The conditions of conditioing process to get uniform removal were also investigated by comparing the simulation with the experiment.

• Journal of the Korean Society for Precision Engineering
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• v.12 no.12
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• pp.165-172
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• 1995

Many algorithms to enhance a speed performance of a robot have been studied, but it's rare to consider disign aspect of a robot arm for time optimal problem. In this paper, section demensions of a robot arm and a velocity profile of an end-effector were optimally designed to minimize the cycle time. Capacity of actuators, deflections of end-effector, and a fundamental natural frequency of the robot arm were constrained in optimal design. For a given path with a trapezoidal velocity profile, torques of each joint were calculated using the inverse kinematics and dynamics. For the SCARA type robot which is mainly used for assembly tasks, the time optimal design of each robot arm id presented with the above constraints.

• Journal of KIISE:Software and Applications
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• v.32 no.3
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• pp.227-235
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• 2005

In the embedded system domain, both memory requirement and energy consumption are great concerns. To save memory and energy, the 32 bit ARM processor supports the 16 bit Thumb instruction set. For a given program, the Thumb code is typically smaller than the ARM code. However, the limitations of the Thumb instruction set can often lead to generation of poorer quality code. To generate codes with smaller size but a little slower execution speed, Krishnaswarmy suggests a profiling guided selection algorithm at module level for generating mixed ARM and Thumb codes for application programs. The resulting codes of the algorithm give significant code size reductions with a little loss in performance. When the instruction set is selected at module level, some functions, which should be compiled in Thumb mode to reduce code size, are compiled to ARM code. It means we have additional code size reduction chance. In this paper, we propose a profile guided selection algorithm at function level for generating mixed ARM and Thumb codes for application programs so that the resulting codes give additional code size reductions without loss in performance compared to the module level algorithm. We can reduce 2.7％ code size additionally with no performance penalty

• Journal of the Korean Society for Precision Engineering
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• v.9 no.4
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• pp.136-146
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• 1992

This paper provides the end-point positioning of a single-link flexible robot arm by inverse dynamics. The system is composed of a flexible arm, the mobile ballscrew stage as an arm base, a DC servomotor as an actuator, and a computer. Actuator voltages required for the model of a flexible arm to follow a given tip trajectory are formulated on the basis of the Bermoullie-Euler beam theory and solved by applying the Laplace transform method, and computed by the numerical inversion method proposed by Weeks. The mobile stage as the arm base is shifted so that the end-point follows the desired trajectories. Then the trajectory of end-point is measured by the laser displacement sensor. Here, two kinds of functions are chosen for the given tip trajectories. One is what is called the bang-bang acceleration profile and the other is the Gaussian velocity profile.

• Journal of Mechanical Science and Technology
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• v.19 no.8
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• pp.1576-1581
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• 2005

Generally, the optical components are fabricated by grinding, lapping, and polishing. And, those processes take long time to obtain such a high surface quality. Therefore, in the case of large optical component, the on-machine inspection (OMI) is essential. Because, the work piece is fragile and difficult to set up for fabricating and measuring. This paper is concerned about a swing-arm method for measuring surface profile of large optical concave mirror. The measuring accuracy and uncertainty for suggested method are studied. The experimental results show that this method is useful specially in lapping process with the accuracy of $3\~5\;{\mu}m$. Those inspection data are provided for correcting the residual figuring error in lapping or polishing processes.

• Journal of KSNVE
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• v.9 no.3
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• pp.613-620
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• 1999

Brake judder{or cold judder) caused by the disc thickness variation(DTV) is investigated experimentally, This cold judder is often perceived by steering wheel vibration, brake pedal pulsation, and vehicle body vibration. In this paper, how the DTV profile affects the vibration characteristics of vehicle body is shown by order tracking analysis(OTA) and operational vibration analysis(OVA) The tri-axial vibrations are measured at the knuckle, lower rm, and the body side of the lower arm. Also, measured are the wheel speed and the detail DTV profile. The interpretations of OTA results in three directions of tested vehicle indicate the relative importance in the contribution of the run-out and the DTV to the judder vibration. Also, the OVA results show the prominent vibration amplitude of the lower arm in the direction of the vehicle movement. in which the second order of wheel speed is dominant. These results could be used to diagnose the judder problem and to establish the correction methods.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1996.10a
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• pp.197-202
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• 1996

The dynamic interaction between a translating flexible arm and a trapezoidal velocity profile of a cart to which the flexible arm is attached is presented. Vibration of the flexible arm due to translation is analytically solved, and the conditions for suppressing vibration is derived in terms of velocity profiles. To prove the validity of the solution and the conditions, numerical computation and experiments are camed out. Only a natural frequency of vibrating plant is needed to obtain the conditions for vibration reduction. With this results, a passive vibration regulator as an open loop control scheme can be designed and direct application to industrial plants such as overhead crane can be made.

• Tribology and Lubricants
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• v.40 no.2
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• pp.67-70
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• 2024

Chemical mechanical planarization (CMP) is an essential process for ensuring high integration when manufacturing semiconductor devices. CMP mainly requires the use of polyurethane-based polishing pads as an ultraprecise process to achieve mechanical material removal and the required chemical reactions. A diamond disk performs pad conditioning to remove processing residues on the pad surface and maintain sufficient surface roughness during CMP. However, the diamond grits attached to the disk cause uneven wear of the pad, leading to the poor uniformity of material removal during CMP. This study investigates the pad wear rate profile according to the swing motion of the conditioner during swing-arm-type CMP conditioning using deep learning. During conditioning, the motion of the swing arm is independently controlled in eight zones of the same pad radius. The experiment includes six swingmotion conditions to obtain actual data on the pad wear rate profile, and deep learning learns the pad wear rate profile obtained in the experiment. The absolute average error rate between the experimental values and learning results is 0.01%. This finding confirms that the experimental results can be well represented by learning. Pad wear rate profile prediction using the learning results reveals good agreement between the predicted and experimental values.