• The Transactions of the Korean Institute of Electrical Engineers D
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• v.54 no.1
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• pp.33-39
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• 2005

In this paper, we propose a slider servo-mechanism driven by electro-magnetic actuator to improve straightness of linear motor stages. Based on axial-position dependent deterministic characteristics of the straightness error, a feedforward compensation control is appled to reduce the straightness error. In the consideration of uncertain properties of friction and its effects on positioning accuracy, a sliding mode control is applied. The effectiveness of the suggested mechanism and the control performances are illustrated along with some experimental results.

• Proceedings of the Korean Society Of Semiconductor Equipment Technology
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• 2007.06a
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• pp.11-14
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• 2007

An additive servo-system is developed to improve straightness of linear motor stages. For linear motor stages used in the field of high-precision linear motion process, high straightness accuracy is necessary as well as positioning accuracy in the longitudinal axis. In such cases, machining and assembling cost increases to improve the straightness accuracy. An electro-magnetic actuator which is relatively cost effective than any other conventional servo-systems is suggested to compensate the fixed straightness error. To overcome the compensation error due to modeling error and friction disturbance, a sliding mode control is addressed. The effectiveness of the suggested mechanism and the control are illustrated along with some experimental results.

• Proceedings of the Technology Innovation Conference
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• 2000.06a
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• pp.105-120
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• 2000

Rapid spread of Internet, there appear so many commercial wedsites. Websites are not only tools to advertise a company or a product, but also value-added products inself. So we need a systematic approach(planning, design, implementation) to develop a website. But existing reserches on website development have corvered only technological issues such as network and HCI(Human Computer Intercation). In this research a framework is proposed to develop a website systematically using database of existing websites. This framework is composed of several stages-target customer segmentation, determination of services on website, dtermination of business model, functinal positioning, and evaution.

• Journal of Ocean Engineering and Technology
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• v.25 no.4
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• pp.1-6
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• 2011

The installation of a topside structure can be categorized into the following stages: start, pre-lifting, lifting, lifted, rotating, positioning, lowering, mating, and end of installation. The transfer of the module onto the floating spar hull occurs in the last three stages, from lowering to the end. The coupled multi-body motions are calculated in both calm water and in irregular waves with a significant wave height (1.52m). The effects of the hydrodynamic interactions between the heavy lifting vessel and the spar hull during the lowering and mating stages are considered. The internal forces caused by the load transfer and ballasting are derived for the mating phases. The results of the internal forces for the calm water condition are compared with those in the irregular sea condition. Although the effect of the pitch motion on the relative vertical motion between the deck of the floating structure and the topside module is significant in the mating phases, the internal force induced pitch motion is too small to have this influence. However, the effect of the internal force on the wave-induced heave responses in the mating phases is noticeable in the irregular sea condition because transfer mass-induced draught changes for the floating structure are observed to have higher amplitudes than the external force induced responses. The impacts of the module on the spar hull in the mating phase are investigated.

• Journal of Ocean Engineering and Technology
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• v.25 no.4
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• pp.7-11
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• 2011

The installation phase for a topside module suggested can be divided into 9 stages, which include start, pre-lifting, lifting, lifted, rotating, positioning, lowering, mating, and end of installation. The transfer of the topside module from a transport barge to a crane vessel takes place in the first three stages, from start to lifting, while the transfer of the module onto a floating spar hull occurs in the last three stages, from lowering to the end. The coupled multi-body motions are calculated in both calm water and in irregular waves with significant wave height (1.52m), with suggested force equilibrium diagrams. The effects of the hydrodynamic interactions between the crane vessel and barge during the lifting stage have been considered. The internal forces caused by the load transfer and ballasting are derived for the lifting phases. The results of these internal forces for the calm water condition are compared with those in the irregular sea condition. Although the effect of pitch motion on the relative vertical motion between the deck of the floating structure and the topside module is significant in the lifting phases, the internal force induced pitch motion is too small to show its influence. However, the effect of the internal force on the wave-induced heave responses in the lifting phases is noticeable in the irregular sea condition because the transfer mass-induced draught changes in the floating structure are observed to have higher amplitudes than the external force induced responses.

• International Journal of Naval Architecture and Ocean Engineering
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• v.5 no.3
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• pp.431-453
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• 2013

The principal purpose of this paper is to present a novel two phases rational scenario applied in constructing an offshore monopod platform; in which the two phases are the all-ground horizontal construction phase and the post-construction phase. Concerning the all-ground construction phase, a brief investigation of its different stages, i.e., pre-fabrication, fabrication, pre-assembling, positioning, assembling, and surface finishing is introduced. The important practical aspects of such construction phase are investigated without going into the nitty-gritty of the details involved therein. Concerning the post-construction phase, a clear investigation of its sequential stages, i.e., lifting, moving and up-righting is introduced. A finite element model (FEM) of the monopod platform is created to perform the structural analysis necessary to decide the suspension points/devices and the handling scenario during the various stages of the post-construction phase on a rational wise. Such structural analysis is performed within the framework of the three dimensional quasi-static modeling and analysis aiming at simulating the realistic handling condition, and hence introducing a reliable physical interpretation of the numerical results. For the whole effort to be demonstrated efficiently, the results obtained are analyzed, the conclusions are presented, and few related recommendations are suggested.

• Proceedings of the Korean Society of Medical Physics Conference
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• 2002.09a
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• pp.324-327
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• 2002

For a next generation PET that realizes high sensitivity and high resolution, we proposed a design of a depth of interaction detector. A unit of the detector is constructed of four stages rectangular blocks of 2 by 2 Gd$_2$SiO$\sub$5/: Ce (GSO) crystal array optically coupled to position sensitive photomultiplier tube (PS-PMT). The 256ch flat panel PS-PMT is under development by Hamamatsu Photonics K.K., JAPAN. It has large cathode area, 51.7 by 51.7 mm$^2$, and the ratio of the effective area to external size is about 90%. The feature will contribute high packing fraction, accordingly high sensitivity. The 256 anodes are arranged in 16 by 16 at intervals of 3.0 mm. So as to evaluate the detector capability for identifying crystal of interaction, we got positioning image histograms with coupling a 16 by 5 array of GSO crystals, 2.9 by 2.9 by 7.5 mm$^3$, to the PS-PMT by irradiating a gamma ray uniformly from a point source. Flat panel PS-PMT is a new promising device for PET. We need to evaluate it if its performance is sufficiency. The performance was compared to the one with a 16ch PS-PMT.

• Journal of the Korean Society for Precision Engineering
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• v.25 no.12
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• pp.132-138
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• 2008

Recently, mastering processes for high density optical disc such as Blu-ray disc rely on electron beams, which are operable in only vacuum. In the mastering process, one of the most important tasks is to design precision stages for providing precise positioning of the works with respect to the source in a high vacuum environment. In this paper, we have developed a precision rotation table usable in the electron beam mastering. The rotation table adopted air bearings for a high positioning repeatability and velocity stability. The air leakage from the air bearings has been minimized by employing the differential exhaust scheme using three steps of air drain. The design parameters such as diameters of exhaust lines, seal lengths, and pumping speeds were decided according to the optimization method using genetic algorithm. The performance on the vacuum level of the rotation table was evaluated experimentally and theoretically. The results indicate that a vacuum level of $10^{-4}$ Pa is achieved with operation of air bearings in a vacuum chamber, which is sufficient for the electron beam mastering.

• Journal of the Korean association of regional geographers
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• v.11 no.5
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• pp.405-425
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• 2005

Transition from mass tourism to post tourism is closely related with developing various types of cultural tourism. This study attempts to construct a conceptual framework of the development of cultural tourism through identifying the existing development stages of cultural tourism sites from birth to full development. This study clarifies that there exists an organic system among tourism, cultural activities and the production of cultural artifacts. It also found that development of cultural tourism sites goes through the following three stages: positioning and building place image, hard branding, and constructing local system. This study analyzes several key elements for respective of stages, which proved helpful in understanding the development mechanism of cultural tourism sites. It also tries to analyze tourism from an integrated, geographical perspective. The analysis gives us an understanding to the relations between tourism and various aspects of regional society and economy, thus contributing to the development of a system that will lead to active interchanges among those factors. Most of the theoretical background of this study: place identity, place image, activity space, local system and network are based on the concepts and ideas of human geography.

• Journal of Korean Academy of Nursing
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• v.32 no.6
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• pp.832-843
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• 2002

The aim of this study was to describe women's embarrassability and embarrassment during cervical screening. Method: The subjects of this study were 82 women who had a cervical screening at a National University Hospital. The data were collected through personal interview using a questionnaire from February 4, 2001 to February 22, 2002. The questionnaire consisted of embarrassability scale, embarrassment Scale, and demographic data. Result: 1) The mean scores of situational embarrassability was 82.6 and that of dispositional embarrassability was 106.7. 2) The mean scores of subject's embarrassment was 54.3 and 48.7 in 10 stages of cervical screening. The following three situations of 10 stages of cervical screening were highly ranked as to be embarrassing: 'during the examination', 'waiting for a doctor', and 'climbing up the exam chair and positioning her thigh for a exam'. 3) There was a positive correlation between dispositional embarrassability and embarrassment of 10 stages of cervical screening. 4) There were significant differences in situational embarrassability of subjects according to education and the locations of service. There were significant differences in dispositional embarrassability of subjects with regard to frequencies of pregnancy. 5) There were significant differences in embarrassment of subjects during cervical screening with respect to age, age at the time of first smear and gender of the examiner. Conclusion: The finding of this study indicates that women experienced a high level of embarrassment during cervical screening, assuming a need for nursing intervention reduces women's embarrassment. Also, there is a positive correlation between embarrassability and embarrassment of cervical screening, suggesting a need for further research identifying the effect of nursing intervention on embarrassment according to embarrassability.