• Journal of Institute of Control, Robotics and Systems
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• v.13 no.7
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• pp.624-630
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• 2007

The dynamic window approach(DWA) is a well known technique for reactive collision avoidance. It shows safe and efficient performance in real-world experiments. However, a robot can get stuck in local minima because no information about the connectivity of the free space is used to determine the motion. The global DWA can solve this problem of local minima by adding a navigation function. Even with the global DWA, it is still difficult for a robot to execute an abrupt change in its direction, for example, entering from the corridor to a doorway. This paper proposes a modified global DWA using the included angles of waypoints extracted from an optimal path. This scheme enables the robot to decelerate in advance before turning into the doorway. Therefore the robot can reach the goal position more safely and efficiently at high speeds.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1999.10a
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• pp.40-45
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• 1999

The demands for robotic and automatic system are continually increasing in manufacturing fields. There have been many studies to monitor and predict the system, but they have mainly focused upon measuring cutting force, and current of motor spindle, and upon using acoustic sensor, etc.In this study, time series sequence of cutting force was acquired by taking advantage of piezoelectric type tool dynamometer. Radial cutting force was obtained from it and was available for useful observation data. The parameter was estimated using PAA (parameter adaptation algorithm) from observation data. ARMA(auto regressive moving average) model was selected for system model and second order was decided according to parameter estimation. Uncorrelation test was also carried out to verify convergence of parameter.

• Proceedings of the KSR Conference
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• 2009.05a
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• pp.1191-1197
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• 2009

KTX decelerator is a device to fulfil a role of transmission of turning force to reduction device of an axle by serrate device. Currently, KTX decelerator's TBO(Time Between Overhaul) has 3 years cycle. As for the dissembly maintenance of a device, its maintenance is conducted every 1.4M kms. In this study, since opening of KTX, we analyzed reliability, maintainability, availability of KTX decelerator by researching historical records of maintenance of the decelerator, and based on above data, investigated whether its TBO cycle and maintenance works properly or not And we considered maintenance policies of KTX decelerator to improve efficiency in maintenance in the future.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.20 no.3
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• pp.350-356
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• 2011

In this paper, we proposed the automatic cutting mechanism of the perforation pipes in an automobile muffler. This cutting mechanism makes continuous work possible, because it performs the batch work via the sequential operation of loading, feeding, cutting, and discharging. The proposed cutting mechanism consists of the frame unit, escape unit, turning unit, feeding unit, vision system, clamping unit, spindle/cutting unit and cooling unit. And, these mechanisms have been modularized through mechanical, dynamical and structural optimized design using the SMO (SimDesigner Motion) analysis module. Also, the virtual prototype was carried out using the 3-D CAD program. The cutting process cycle is performed in the order of loading, vision processing, feeding, clamping, cutting and discharging. And the cycle time for cutting one piece was designed to be completed in four seconds.

• Korean Institute of Interior Design Journal
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• no.37
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• pp.48-54
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• 2003

This study investigates great potential of architectural representation drawings for architects as well as designers to realize their design concept into visual forms. In 1988, an exhibition called "Deconstruction in Architecture" at Modern Art Museum, New York, was an important turning point in design representation. The study examines design drawings of architects of deconstructivism to analyze new attitudes toward building forms and programs in contemporary architecture. The study found in the drawings that initially, collages in many different types are often utilized to express simultaneous time and space. Secondly, section drawings become more important to explain ambiguous and complex floor system than before. Thirdly, cinematic montages are utilized to express indeterminate or loose programs. Fourthly, diagrams are utilized to visualize initial conditions and clues of design solution. The study concludes that design drawings are not only representation media admitting of changes and progress but also tools of design creation. creation.

• Journal of the Korean Society for Precision Engineering
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• v.5 no.1
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• pp.71-77
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• 1988

This study applies dynamic deformation analysis to the rake face stress distribution of cemented carbide cut-off tools by turning, using a finite element method. The results are following: 1. The dynamic loaded state of a cut-off tool was very changeable for the first 0.6 seconds. Reaching the normal state, it became in active. 2. Chipping was influnced not only by the magnitude of stress but also by the abrupt change of tensile and compressive stresses. 3. The distribution chat of principal stress by dynamic load and the direction of resultant vector were almost constant regardless of load time.

• Journal of the Korean Society for Precision Engineering
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• v.7 no.2
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• pp.47-57
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• 1990

In-process recognition of the cutting states is one of the very important technologies to increase the reliability of mordern machining process. In this study, practical methods which use the dynamic component of the cutting force are proposed to recognize cutting states (i.e. chip formation, tool wear, surface roughness) in turning process. The signal processing method developed in this study is efficient to measure the maximum amplitude of the dynamic component of cutting force which is closely related to the chip breaking (cut-off frequency : 80-500 Hz) and the approximately natural frequency of cutting tool (5, 000-8, 000 Hz). It can be clarified that the monitoring of the maximum apmlitude in the dynamic component of the cutting force enables the state of chip formation which chips can be easily hancled and the inferiority state of the machined surface to be recognized. The microcomputer in-process tool wear monitor- ing system introduced in this paper can detect the determination of the time to change cutting tool.

• Journal of Drive and Control
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• v.16 no.2
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• pp.36-42
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• 2019

The ESP (Electronic Stability Program) is an active control system that controls the posture of the vehicle by sensing the unstable state of the vehicle during braking, driving, or turning. The system works if the vehicle becomes unstable and it is very dangerous to develop it in the actual vehicle. For this reason, many studies have been carried out on the method of developing with simulation such as SIL / EIL. Some advanced companies have already applied it to the product development process. In this study, ESP hydraulic system and braking device model were constructed using SimulationX to build ESP SIL / EIL model. The hydraulic system model was constructed using the actual design parameters and the performance of the hydraulic model was verified by comparing with the actual vehicle test.

• Food Science and Industry
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• v.55 no.1
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• pp.74-94
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• 2022

With the discovery of metabolic mechanisms of alcohol fermentation and acetic acid fermentation in the 1800s and 1900s, the history of traditional vinegar became a turning point for changing to the history of science and technology. Since then, innovation in vinegar production has occurred, and the era of full-scale mass industrialization has opened. The most modern method, submerged fermentation, has improved the vinegar production process to produce much higher quality vinegar and provide vinegar with high productivity and quality uniformity. Innovative research for vinegar production is underway as various approaches have been developed to increase fermentation efficiency, reduce costs, and shorten fermentation time due to the trend of combining existing technologies and advanced technologies. Now that the development of the vinegar industry is currently focused on vinegar engineering, multidisciplinary approaches in various fields such as microbiology, chemistry, food technology, process engineering, and molecular biology are needed.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2022.06a
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• pp.31-32
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• 2022

In Early vessels did not provide an exact equation for preventig the capsizing vessels. On land, many vehicle rollover prevention technologies using the steady-state Conrning Equations were developed, which showed better performance than the exiting method at sea. For better performance, It is proposed to improve safety mangement when turning vessel using the Ackerman geometic model-based Cornering Equations in this paper.