• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.309-312
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• 2005

DTM (Diamond Turning Machine) is using for ultra precision manufacturing such as, plastic lens die or aspherical optics. This study is on a design of precision 2-axis stage for DTM. We designed and manufactured a back lash free stage using different weights and measured the positioning accuracy using Interferometer. Also, the 2-D moving accuracy is measured using the high magnification CCD technique. Then, the stage is tested with the machining of spherical and aspherical lens in a DTM with air bearing spindle. It was shown that the back lash free stage is effective for improving the positioning accuracy. Also, positioning control errors in motion control board were able to be found using the proposed stages system.

• Journal of the Korean Society for Precision Engineering
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• v.21 no.3
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• pp.147-154
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• 2004

This paper presents a procedure for analysis and design of a fine positioning stage, which has many applications in industries for machine tools, semiconductor, LCD and so forth. The stage considered here is based on a single module with 3 axes which is composed of flexures hinges, piezoelectric actuators and their peripherals. Through a series of analysis, the structural analysis model is simplified as a rigid body(the moving part) and springs(the flexures hinges). An experimental design procedure is applied to determine the dimension of flexures hinges. A sensitivity analysis on the notch positions is also performed to obtain a guideline of fabrication accuracy for the stage. An actual fine stage is made and verified through an experiment on the dynamic characteristics.

• Journal of Biosystems Engineering
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• v.42 no.2
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• pp.117-125
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• 2017

Purpose: Damage to pulse crops by wild birds is a serious problem. The damage is to such an extent that the rate of damage during the period between seeding and cotyledon stages reaches 54.6% on an average. In this study, a crop-position detection method was developed wherein infrared (IR) sensors were used to determine the cotyledon position under a vinyl mulch. Methods: IR sensors that helped measure the temperature were used to locate the cotyledons below the vinyl mulch. A single IR sensor module was installed at three locations of the crops (peanut, red lettuce, and crown daisy) in the cotyledon stage. The representative thermal response of a $16{\times}4$ pixel area was detected using this sensor in the case where the distance from the target was 25 cm. A spatial image was applied to the two-dimensional temperature distribution using a non-integral moving-average method. The collected data were first processed by taking the moving average via interpolation to determine the frame where the variance was the lowest for a resolution unit of 1.02 cm. Results: The temperature distribution was plotted corresponding to a distance of 10 cm between the crops. A clear leaf pattern of the crop was visually confirmed. However, the temperature distribution after the normalization was unclear. The image conversion and frequency-conversion graphs were obtained based on the moving average by averaging the points corresponding to a frequency of 40 Hz for 8 pixels. The most optimized resolutions at locations 1, 2, and 3 were found on 3.4, 4.1, and 5.6 Pixels, respectively. Conclusions: In this study, to solve the problem of damage caused by birds to crops in the cotyledon stage after seeding, the vinyl mulch is punched after seeding. The crops in the cotyledon stage could be accurately located using the proposed method. By conducting the experiments using the single IR sensor and a sliding mechanical device with the help of a non-integral interpolation method, the crops in the cotyledon stage could be precisely located.

• Journal of the Korean Society for Precision Engineering
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• v.22 no.9 s.174
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• pp.69-76
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• 2005

The laser interferometer system such as HP5529A is one of the most powerful equipment fur measurement of the straightness error in precision stages. The straightness measurement system, HP5529A is composed of a Wollaston prism and a reflector. In this system, the straightness error is defined as relative lateral motion change between the prism and the reflector and computed from optical path difference of two polarized laser beams between these optics. However, rotating motion of the prism or the reflector used as a moving optic causes unwanted straightness error. In this paper, a compensation method is proposed for removing the unwanted straightness error generated by rotating the moving optic and an experiment is carried out for theoretical verification. The result shows that the unwanted straightness error becomes very large when the reflector is used as the moving optic and the distance between the reflector and the prism is far. Therefore, the prism must be generally used as the moving optic instead of the reflector so as to reduce the measurement error. Nevertheless, the measurement error must be compensated because it's not a negligible error if a rotating angle of the prism is large. In case the reflector must be used as the moving optic, which is unavoidable when the squareness error is measured between two axes, this compensation method can be applied and produces a better result.

• Korean Institute of Interior Design Journal
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• v.14 no.6 s.53
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• pp.236-243
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• 2005

The pre-examination closely beforehand relation between the articles on exhibition and visitors, the visitors and exhibition space, the exhibition space and the articles on exhibition, and the acceptance of various requirements are the matters you should consider in the initial stage when planning the establishment of a museum. Especially, the clear guideline for the layout of exhibition to meet the intention of spectators considered based on the seeing behavior in the exhibition hall (i.e. they see the articles on exhibition in order passively under instructions of the museum or select them by themselves positively etc.), and the moving line of appreciation and the exhibition type seems to be not yet prepared sufficiently. This study can be defined as the study of fundamental background for the architectural guideline for the characteristics of visitor's behavior, the selected moving line in the exhibition hall, the layout against the forced moving line and the type of exhibition space. As a part of this study, we carried out the research and the study for how the movement of visitors and the characteristics of seeing behaviors according to the type of the moving line are shown, based on the type of moving line for seeing suggested by David Dean.

• Fashion & Textile Research Journal
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• v.13 no.3
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• pp.390-397
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• 2011

This study investigates the influences of shopping enjoyment and risk reduction on customers' attitude and the behavioral intention in the Internet shopping mall using a moving virtual model. For this study, we produced a moving virtual model to present a fashion product. The virtual model walks for about one minute on the stage. After respondents viewed it, they completed a questionnaire. The questionnaire consists of online shopping enjoyment, risk reduction, customers' attitude and behavioral intention. Respondents are limited to females aged in their 20s and 30s, who have experienced Internet shopping and are highly interested in fashion products. 411 samples were used for the final analysis. Cronbach's alpha, factor analysis, and multiple regression analysis were conducted. The results are as follows. Online shopping enjoyment and risk reduction influenced the behavioral intention directly as well as through the attitude. However, the size of the influence indicated that online shopping enjoyment is larger than risk reduction. Therefore, Internet malls should utilize the moving virtual model to provide customers with enjoyment and risk reduction, which will increase customers' favorable attitudes and the behavioral intention such as purchase intention and word of mouth.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.1380-1383
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• 2004

The scanning type XY stage is frequently used these days as precision positioning system in equipment for semiconductor or display element. It is requested higher velocity and more precise accuracy for higher productivity and measuring performance. The position accuracy of general stage is primarily affected by the geometric errors caused by parasitic motion of stage, misalignments such as perpendicular error, and thermal expansion of structure. In the case of scanning type stage, H type frame is usually used as base stage which is driven by two actuators such as linear motor. In the point view of scanning process, the stage is used in moving motion. Therefore, dynamic variation is added as significant position error source with other parasitic motion error. Because the scanning axis is driven by two actuators with two position detectors, 2 dimensional position errors have different characteristic compared to general tacked type XY stage. In this study 2D position error of scanning stage is analyzed by 1D heterodyne interferometer calibrator, which can measure 1D linear position error, straightness error, yaw error and pitch error, and perpendicular error. The 2D position error is evaluated by diagonal measurement (ISO230-6). The yaw error and perpendicular error are compensated on the base stage of scanning axis. And, the horizontal straightness error is compensated by cross axis compensation. And, dynamic motion error in scanning motion is analyzed.

• Journal of the Korea Safety Management & Science
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• v.22 no.1
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• pp.45-50
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• 2020

The number of elevators in Korea has surpassed 700,000 units in 2019, which is the 8th in the world by number of installed units and 3rd in the world by new units. The word 'lift' is a representative word, and the category includes elevators, escalators, dumb waiters, and moving walks. Those who live in the city will experience using elevators once or twice a day, and these elevators are becoming an indispensable means of transportation when using high-rise apartments or subways. However, such a convenient elevator also has a lot of risks that threaten the safety of the user and actually cause many accidents every year. In particular, escalators (including moving walks), which account for as little as 5% of all elevators, account for 70% of all elevator accidents. According to Heinrich's chain of thought theory, accidents are caused by a combination of factors, which are divided into five stages: Stage 1: Genetic Factors and Social Environment, Stage 2: Individual Defects, Stage 3: Unsafe behavior and Unsafe conditions, Stage 4: Accident, Stage 5: Injury. Heinrich said that three of these five phases, unsafe behavior and unsafe conditions, require safety management and efforts to prevent accidents. In escalator accidents, the analysis of accident cases that have occurred so far will be related to unsafe behaviors and unsafe conditions, and the effective management of these causes of accidents will enable safer and more convenient use of escalators. This study analyzed accident cases of elevator users, focusing on escalator accidents over the last 10 years (2010 ~ 2019), and safety management to prevent safety accidents of elevator users by analyzing the behavior of actual users and questionnaires of experts in related fields. The method was studied.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.14 no.3
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• pp.23-31
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• 2005

The purpose of this study is to design a disturbance observer for a micro-stepping stage to eliminate the disturbances from cables, friction, mass unbalance of the moving part, etc. The disturbance observer is designed for air-floating X-Y precision micro-stepping X-Y stage which widely used in stepper machine or semiconductor manufacturing systems. The micro-stepping X-Y stage has a weak point of the variation of characteristics with position locations, which caused by various disturbances. In this study, it will be described that a simple and high throughput disturbance observer algorithm improves the dynamic error and settling time of the micro-stepping stage.

• International Journal of Control, Automation, and Systems
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• v.4 no.1
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• pp.1-9
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• 2006

This paper presents the modeling and multivariable feedback control of a novel high-precision multi-dimensional positioning stage. This integrated 6-degree-of-freedom. (DOF) motion stage is levitated by three aerostatic bearings and actuated by 3 three-phase synchronous permanent-magnet planar motors (SPMPMs). It can generate all 6-DOF motions with only a single moving part. With the DQ decomposition theory, this positioning stage is modeled as a multi-input multi-output (MIMO) electromechanical system with six inputs (currents) and six outputs (displacements). To achieve high-precision positioning capability, discrete-time integrator-augmented linear-quadratic-regulator (LQR) and reduced-order linearquadratic-Gaussian (LQG) control methodologies are applied. Digital multivariable controllers are designed and implemented on the positioning system, and experimental results are also presented in this paper to demonstrate the stage's dynamic performance.