• Proceedings of the Korea Society of Design Studies Conference
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• 2001.10a
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• pp.30.1-30
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• 2001

• Transactions of the Korean Society of Mechanical Engineers A
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• v.28 no.7
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• pp.986-991
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• 2004

For volumetric error measurement and calibration for machine tools, manufacturing machine or coordinate measuring machine (CMM), are studied using a Ball-bar artifact. A design of the Ball-bar is suggested manufactured by Invar, which is a low thermal expansion material, and precision steel balls. The uncertainty for the artifact method is discussed. A method of the Ball-bar artifact for obtaining 3-D position errors in CMM is proposed. The method of error vector measurement is shown using the Ball-bar artifact. Finally, the volumetric error is calculated from the error vectors and it can be used for Pitch error compensation in conventional NC machine and 3-D position Error map for calibration of NC machine tools.

• Journal of Electrical Engineering and Technology
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• v.9 no.5
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• pp.1780-1787
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• 2014

Arterial oxygen saturation ($SpO_2$) monitoring for newborns requires special attention in neonatal intensive care units (NICUs). Newborns have very low photo-plethysmogram (PPG) amplitudes and their body movements are difficult to contain. Hardware design and its associated signal processing algorithms should be robust enough so that faulty measurements can be avoided. In this study, improved designs were implemented to deal with low perfusion, motion artifact, and the influence of ambient light. Dynamic range was increased by using different LED intensities and a feedback system. To minimize the effects of motion artifact and to discard other unqualified data, four additional algorithms were used, which were based on dual-trace detection, continuity of DC level, morphology of PPG, and simultaneity check of $SpO_2$. Our $SpO_2$ system was tested with newborns with normal respiration in the NICU. Our system provided fast, real-time responses and 100% artifact detection was accomplished under 84% of $SpO_2$.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2001.04a
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• pp.143-148
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• 2001

Volumetric error measurement and calibration of a coordinate measuring machine are studied by using a Ball-Bar artifact. Examples of the Ball-Bar design are shown using inbar materials and precision steel balls. Also, for the uncertainty error using the Ball-Bar is discussed. Method of Ball-Bar artifact and the analysis of the error vectors are proposed. Using the Ball-Bar data, we studied the method of volumetric errors ana]ysis of a coordinate measuring machine.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.12
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• pp.2899-2908
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• 2000

Methodology of volumetric error identification is presented to improve the accuracy of NC machine tools by using a reference artifact and a touch trigger probe. Homogeneous transformation matrix and kinematic chain are used for modeling the geometric and thermal errors of a three-axis vertical machining center. The reference artifact is designed and fabricated to identify the model parameters by machine tool metrology. Parameters in the error model are able to be identified and updated by direct measurement of the reference artifact on the machine tool under the actual conditions which include the thermal interactions of error sources. The proposed method can speed up and simplify volumetric error identification processes.

• Proceedings of the KOSOMBE Conference
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• v.1998 no.11
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• pp.279-280
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• 1998

A new algorithm is developed that can reduce the metal artifact on CT caused by pedicle screws. Metal artifact has been recognized as a major problem in precise reading of CT images. In particular, spine surgeons have been bothered with the artifact appearing on CT taken after pedicle screw insertion. To reduce the artifact, our new algorithm first finds the center line from CT images, and then overlays an exact size screw image on the CT. The exact screw is obtained from an actual design specifications of screw, and the CT images are processed to maximize bone margins while minimizing screw images through adjusting the window width and level. 실험 결과 단순한 Window W/L 조절로는 해결되지 않는군요. This algorithm provides spine surgeons with more accurate CT images and thus better interpretation of CT to ascertain the success or failure of pedicle screw insertion.

• Structural Engineering and Mechanics
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• v.78 no.3
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• pp.333-350
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• 2021

Motivated by the demand of seismic protection of museum collections and development of performance-based seismic design guidelines, this paper investigates the seismic fragility of sliding artifacts based on incremental dynamic analysis and three-dimensional finite element model of the artifact-showcase-museum system considering nonlinear behavior of the structure and contact interfaces. Different intensity measures (IMs) for seismic fragility assessment of sliding artifacts are compared. The fragility curves of the sliding artifacts in both freestanding and restrained showcases placed on different floors of a four-story reinforced concrete frame structure are developed. The seismic sliding fragility of the artifacts within a real-world museum subjected to bi-directional horizontal ground motions is also assessed using the proposed IM and engineering demand parameter. Results show that the peak floor acceleration including only values initiating sliding is an efficient IM. Moreover, the sliding fragility estimate for the artifact in the restrained showcase increases as the floor level goes higher, while it may not be true in the freestanding showcase. Furthermore, the artifact is more prone to sliding failure in the restrained showcase than the freestanding showcase. In addition, the artifact has slightly worse sliding performance subjected to bi-directional motions than major-component motions.

• Journal of Industrial Technology
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• v.26 no.A
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• pp.89-93
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• 2006

Pulse oximetry, which monitors non-invasively the oxygen saturation in blood, is influenced by patient's respiration, movement or a factor of an environment. Specially, it's difficult to measure a PPG (Photoplethsmography) signal from the moving patient because of the motion artifact. Accordingly, it is required to extract the pure PPG signal from the PPG signal to measure oxygen saturation. In this paper, we propose an adaptive noise canceller to improve the performance of motion artifact removal. Then we design a hardware system for real time monitoring of the oxygen saturation. The proposed algorithm estimates the slope of transition rate between two different wavelength signals.

• Archives of design research
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• v.19 no.4 s.66
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• pp.41-50
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• 2006

It is generally regarded a design system in post-industrial society, which products designed by in-house designers or design consultancy are manufactured in factory and distributed in market for the consumer. Although it is treated an old design system in traditional society, the traces of vernacular design has been remaining in the state of adopted to the periodical needs in these days, also proving the attribute of design culture to constitute human's material environment as well as existing design systems. There were discovered various design artifacts in daily surroundings vary from the established design in several manners, user modifications or manufactures in everyday lives formalized them. It was approached a case study that analyze the changes of artifact configuration and designer/user context and creation process of the non-professional design artifacts, Creativity Template Theory and ACM(Artifact Context Model) have been utilized for the analysis model. From the analysis result, It assume that the everyday artifacts may be ordinary but extra-ordinary including particular ideas and identity represented by everyday designers or users. Beside these characteristics induce the potentiality that reflect on creative motives for the designers or a complementary artifact generator filling up with drawbacks in established design system. The everyday design domain, various explorations and alternatives are made, is seems to be another design practice domain dissimilar to the one in the industry-based design. Moreover it provides an more easily accessability for the approaching user-friendly design, user customization because they conduct the reliable modeling of consumer and end-user. Finally, based on the exploratory study regarding interpretation of context and configuration in the everyday artifacts, new approach for the design process and design education through more detailed cognitive modeling of everyday designers will be a further study.

• Journal of Engineering Education Research
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• v.23 no.2
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• pp.3-13
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• 2020

Key objective of cornerstone design is that students are able to experience developing creative design concepts through team activities, but the objective is hard to achieve. Based on a study of research materials, this paper asserts that the possibilities of creative problem solving can be promoted in question-centering ideation model if design artifacts are represented in some forms that could invoke design thinking and then the solution space is appropriately established. In particular, design problem on which divergent questions are asked should be explored and defined so that it can be a linguistic artifact represented by various visual aids. It is recommended that curriculum is modified so that students can experience creative conceptual design.