• Journal of Korean Society for Quality Management
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• v.43 no.4
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• pp.521-532
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• 2015

Purpose: The purpose of this study is to compare two multivariate cumulative sum (MCUSUM) charts designed for spatio-temporal surveillance in terms of not only temporal detection performance but also spatial detection performance. Method: Experiments under various configurations are designed and performed to test two CUSUM charts, namely SMCUSUM and RMCUSUM. In addition to average run length(ARL), two measures of spatial identification accuracy are reported and compared. Results: The RMCUSUM chart provides higher level of spatial identification accuracy while two charts show comparable performance in terms of ARL. Conclusion: The RMCUSUM chart has more flexibility, robustness, and spatial identification accuracy when compared to those of the SMCUSUM chart. We recommend to use the RMCUSUM chart if control limit calibration is not an urgent task.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2010.04a
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• pp.69-71
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• 2010

In this paper, we focus on the accuracy estimation of laser scanning mobile mapping system using Lynx Mobile Mapper. For this, we surveyed checkpoints(181 points) in study areas. A method to estimate the accuracy of laser scanning mobile mapping system based on the measurement range, interval of control points and gps signal environments. As a result, to ensure reliable measurement results, we must be made a plan considering Measure range(60m or under) and operation. The estimation results showed the need for improving accuracy using control points about 150m interval according to environment error source.

• Journal of the Korean Society for Precision Engineering
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• v.22 no.6 s.171
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• pp.7-14
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• 2005

• Korean Journal of Community Nutrition
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• v.12 no.3
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• pp.247-258
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• 2007

This study was conducted to investigate weight control status and associated factors among health-related major female college students. The subjects consisted of 41 nutrition and 78 physical exercise major female college students. Nutrient intakes, biochemical index, nutrition knowledge (recognition and accuracy), interest of weight control, body satisfaction, self-recognition of health condition, self-evaluated body weight were studied. About 73% of nutrition and 79% of physical exercise major female students were in the normal range of BMI ($18.5{\sim}23$) and 2% of nutrition and 1% of physical exercise major female students were underweight, 10% of nutrition and 6% of physical exercise major female students were obese. There were no significant differences in height and weight by major but %body fat and WHR in physical exercise majors were significantly lower than nutrition major students (respectively p<0.01, p<0.05). Overall, nutrition intakes of subjects were not shown to be appropriate, especially Ca/P of subjects was shown $0.54{\sim}0.64$, fat% out of energy of subjects was shown $24.7{\sim}29.0$ and Na intake was shown above 2000mg. Recognition and accuracy of nutrition were higher than those of physical exercise majors (p<0.001). There were no significant differences in self-recognition of health condition, self-evaluated body weight, satisfaction of body shape by major and weight control attempt. But interest of weight control of attempter was higher than that of no-attempter in nutrition (p<0.05) and physical exercise major students (p<0.01). Significantly negative correlation was found in satisfaction of body and BMI, body fat mass, %bodyfat, WHR. And significantly positive correlation was found in interest of weight control and BMI, %bodyfat, WHR. It was noticeable to see that interest of weight control was positively correlated to accuracy and accuracy was negatively correlated to blood cholesterol level. Therefore, proper nutrition education for female college students is needed in order to improve their weight control-related health.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.36 no.6
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• pp.565-572
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• 2018

Recently, UAVs (Unmanned Aerial Vehicles) or drones have gained popularity for the engineering surveying and mapping because they enable the rapid data acquisition and processing as well as their operation cost is low. The applicable fields become much wider including the topographic monitoring, agriculture, and forestry. It is reported that the high geospatial accuracy is achievable with the drone photogrammetry for many applications. However most studies reported the best achievable mapping results using well-distributed ground control points though some studies investigated the impact of control points on the accuracy. In this study, we focused on the drone mapping of corridors such as roads and pipelines. The distribution and the number of control points along the corridor were diversified for the accuracy assessment. In addition, the effects of the camera self-calibration and the number of the image strips were also studied. The experimental results showed that the biased distribution of ground control points has more negative impact on the accuracy compared to the density of points. The prior camera calibration was favored than the on-the-fly self-calibration that may produce poor positional accuracy for the case of less or biased control points. In addition, increasing the number of strips along the corridor was not helpful to increase the positional accuracy.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2002.04a
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• pp.521-527
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• 2002

This paper presents a dynamic modeling and a robust PID controller design process for the wire bonder head assembly. For the modeling elements, the system is divided into electrical system, magnetic system, and mechanical system. Each system is modeled by using the bond graph method. The PID controller is used for high speed/high accuracy position control of the wire bonder assembly. The Taguchi method is used to evaluate the more robust PID gain combinations than conventional one. This study makes use of an L18 array with three parameters varied on three levels. Computer simulations and experimental results show that the designed PID controller provides more improved signal to noise ratio and reduced sensitivity than the conventional PID controller.

• Journal of the Korean Society for Precision Engineering
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• v.23 no.1 s.178
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• pp.201-208
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• 2006

Recently, there are many studies for the micro-machining using Piezo actuator. However, because of its step-by-step motion, it is nearly impossible to increase the machining accuracy for a circular path. To increase the accuracy, it is well known that it is necessary the finer and synchronous movement for x-y axes. Therefore, this paper proposes an adaptive control for finer movement of the actuator, and realizes a synchronous control for the x-y axes. The experimental results show that the machining accuracy is remarkably improved.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2000.10a
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• pp.83-89
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• 2000

This paper presents a dynamic modeling and a sliding mode controller for the high-speed / high-accuracy position control system. Selected target system is the wire bonder head assembly which is used in semiconductor assembly process. This system is a reciprocating one around the pivot point that consists of VCM(voice coil motor) as a actuator and transducer horn as a bonding tool. For the modeling elements, the system is divided into electrical circuit, magnetic circuit and mechanical system. Each system is modeled by using the bond graph method and united into the full system. Two major aims are considered in the design of the controller. The first one is that the horn must track the given reference trajectory. The second one is that the controller must be realizable by using the DSP board. Computer simulation and experimental results show that the designed sliding mode controller provides better performance than the PID controller.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2005.05a
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• pp.446-452
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• 2005

Recently, there are many studies for the micro-machining using Piezo actuator. However, because of its step by step motion, it is nearly impossible to increase the machining accuracy for a circular path. To increase the accuracy, it is well known that it is necessary the finer and synchronous movement for x-y axes. Therefore, this paper proposes a voltage control for finer movement of the actuator, and realizes a synchronous control for the x-y axes. The experimental results show that the machining accuracy is remarkably improved.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1999.05a
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• pp.123-127
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• 1999

This paper suggests the establishment of high-accuracy and high-efficiency machining method of scroll shape workpiece by using the feed control method. The cutting paths for machining the inside and outside surfaces of the scroll-shape workpiece are calculated, and the calculation method of the cutting chip areas based on the coordinate of the base circle is shown. A feed control method is proposed for a constant cutting area and cutting force. By machining test of scroll shape workpiece, The machined accuracy of wrap, tool wear, and surface roughness are evaluated. By this method, Reduction of the machining time and large increase of the efficiency can be expected.