• Journal of the Korean Solar Energy Society
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• v.29 no.3
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• pp.1-11
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• 2009

Heliostat sun tracking accuracy could be the most important requirement in solar thermal power plant, since it determines the overall efficiency of power plant. This study presents the effect of geometrical errors on the heliostat sun tracking performance. The geometrical errors considered here are the mirror canting error, encoder reference error, heliostat position error. pivot offset and tilt error, gear backlash and mass unbalanced effect error. We first investigate the effect of each individual geometrical error on the sun tracking accuracy. Then, the sun tracking error caused by the combination of individual geometrical error is computed and analyzed. The results obtained using the solar ray tracing technique shows that the sun tracking error due to the geometrical error is varying almost randomly. It also shows that the mirror canting error is the most significant error source, while the encoder reference error and gear backlash are second and the third dominant source of errors.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.05a
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• pp.780-785
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• 2003

Recently the trends in information storage devices need small size, mobility, high capacity, and low power consumption etc. To satisfy those, the development of high performance actuator is an important issue. Compared with general linear actuator for optical disk drive, swingarm type rotary actuator is suitable to design in small form factor and has fast access time for random access. Swingarm actuator is designed considering the structural problem and the actuating force of VCM(Voice Coil Motor). The increase of mass caused by optical components makes vibration problems of swing-arm, therefore resonance frequency should be increased and inertia has to be reduced. ANSYS FEM tool is employed in optimizing swingarm. The VCM is designed using 3-D electro-magnetic analysis, and parameters of magnetic circuit are determined to matte large flux density. The large flux density enables to achieve low power consumption. VCM holder is designed to get the mass balance of total actuator and this balance reduces the magnitude of critical mode relative to pivot bearing, It is expected that swingarm type rotary actuator designed by this method is available to variable type of micro optical disk drives.

• Korean Institute of Interior Design Journal
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• v.23 no.1
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• pp.152-161
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• 2014

Beijing, the capital city of China, has gradually increased its amount of culture space and has also introduced a diverse range of cultural facilities to improve the satisfaction of its citizens lives. In particular are its art museums, which are a symbol of the urban culture and enrich the cultural life of its citizens and are also expected to play a role as a psychological pivot point. However, in comparison with the characteristics of various ethics, local, and the influence on the museums of China, studies which analyze the exterior of the art museums are not sufficient. This is because previous research has focused too heavily on the interior of the art museums. This paper aims to derive distinction through the analysis of the exterior of several art museums and present design factors and application methodology. This research looks at art museums in China and analyzes the current state of the art museums that have been developed based on the culture of Beijing. Through analyzing the case study of five art museums that have been selected in Beijing we can improve our understanding of Chinese culture space and derive distinct design factors. Distinct factors in the exterior of art museums include connection, culture, geographic features, public, and creation. This study is expected to contribute to that exterior of the art museum will be as a contact zone to form a spatial connection and a cultural symbol that can reflect Beijing's unique culture characteristics.

• Journal of Korean Institute of Industrial Engineers
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• v.26 no.3
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• pp.257-264
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• 2000

This research suggested a method by which the driver space can be designed to best accommodate the driver's anthropometric characteristics. Three-dimensional manikins and a variable seating buck were developed and used for this study. Manikins were designed with 18 links comprising the 95th percentile male and 5th percentile female data. The seating buck was built to create various driving environments using the distance and the height between the H-point(hip pivot) of the seat and the AHP(accelerator heel point), the angle of the back rest, the angle of the steering wheel, the vertical distance of the steering wheel, and the location of the T.G.S.(transmission gear shift) knob. Measurements of each variable were collected with a coordinate measuring machine by positioning the 3-D manikin under various combinations of the design factors of the seating buck, which was constructed based on mid-size domestic passenger cars. The data were then converted to the joint angles of the driver. The combination of the measurements for an optimal driving environment is suggested by applying sets of the joint angles at which the driver feels comfortable.

• Structural Engineering and Mechanics
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• v.17 no.5
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• pp.611-626
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• 2004

On the basis of a structural analysis of radial gate (i.e. Tainter gate), the current paper focuses on weight minimization according to the location of the arms on a radial gate. In spite of its economical significance, there are hardly any previous studies on the optimum design of radial gate. Accordingly, the present study identifies the optimum position of the support point for a radial gate that guarantees the minimum weight satisfying the strength constraint conditions. This study also identifies the optimum position for 2 or 3 radial arms with a convex cylindrical skin plate relative to a given radius of the skin plate curvature, pivot point, water depth, ice pressure, etc. These optimum designs are then compared with previously constructed radial gates. Local genetic and hybrid-type genetic algorithms are used as the optimum tools to reduce the computing time and enhance the accuracy. The results indicate that the weights of the optimized radial gates are appreciably lower than those of previously constructed gates.

• Journal of the Korean Institute of Navigation
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• v.10 no.1
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• pp.81-100
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• 1986

Self-contained portable remote-indicating magnetic compass was designed and tested. Its sensing part consists of main scale disk of rotary encoder with photo-etched 180, oopaque slits and three pairs of light sources and detectors seperated by a transparent index scale, so that any angular deflection of main scale disk against the bowl may be detected optically. The outputs from the sensing part are transformed into digital ship's course indication by electronics unit which consists of operational amplifier, phase discriminator, up-down counter and counting starter circuit. The results from testign the above compass with turntable at variable rate of turn are as following : 1) The main scale disk deflection against the bowl can be detected without any disturbing influence to the freedom of its north-seeking function. 2) The digital indication resolution is found to be $\circ \pm$1 degree. 3) Misrepresenting indication can be avoided by ensuring dimension uniformity and arrangement accuracy of slits on main and index scale disks and by centering pivot in the encoder disk. 4) Indication resolution should be improved by modifying the signal processing and by doubling the number of slits on compass card. 5) Further study should be made on developing non-conductive compass liquid, analogue repeater driving system and more compact processing element.

• Journal of the Korean Institute of Oriental Medical Informatics
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• v.17 no.2
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• pp.16-72
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• 2011

Precious Mirror of Korean Medicine constitutes the basis of Korean orthodox medicine. In Korea it is regarded as the most influential medical work in existence and therefore been accorded first place among the medical works. Many books and reference works referred to Six Viscera and Five Bowels were quoted in Precious Mirror of Korean Medicine. This dissertation is to study quoted passages and reference books related to Six Bowels and Five Viscera in Precious Mirror of Korean Medicine. Based upon the medical works-Introduction to Medicine, Elementary Questions and Spiritual Pivot of Yellow Emperor's Canon of Internal Medicine, Difficult Classic, Compendium of Medicine, A-B Classic of acupuncture and Moxibustion Pulse Classic, Synopsis of Golden Chamber, Key to Therapeutics of Children's Diseases, A Complete Work of Ancient and Modern Medicine, and etc.-- all but few references the quotations are clearly traced to their origin. It is hoped that this preliminary study will serve as a starting point for further work on the text, with more specific attention to the method of quotations and its many linguistic problems.

• Journal of Sensor Science and Technology
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• v.21 no.2
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• pp.114-120
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• 2012

This paper describes the design, fabrication and testing of a micromachined resonant accelerometer consisting of a symmetrical pair of proof masses and double-ended tuning fork(DETF) oscillators. Under the external acceleration along the input axis, the proof mass applies forces to the oscillators, which causes a change in their resonant frequency. This frequency change is measured to indicate the applied acceleration. Pivot anchor and leverage mechanisms are adopted in the accelerometer to generate larger force from a proof mass under certain acceleration, which enables increasing its scale factor. Finite element method analyses have been conducted to design the accelerometer and a silicon on insulator(SOI) wafer with a substrate glass wafer was used for fabricating it. The fabricated accelerometer has a scale factor of 188 Hz/g, which is shown to be in agreement with analysis results.

• Archives of Craniofacial Surgery
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• v.20 no.5
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• pp.319-323
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• 2019

Cochlear implant extrusion, which is a common complication of cochlear implants, is generally repaired by a well visualized soft-tissue flap. A 61-year-old female patient with a medical history of schizophrenia who had a skin ulcer that caused cochlear implant extrusion, but that would be a stronger statement was referred to our department for removal of the implant and reconstruction of the resultant scalp defect. Accordingly, the broad defect was covered via rotation of a temporoparietal fascia flap (TPFF) using the superficial temporal artery, with the pedicle in the preauricular region as the pivot point. Coverage of TPFF was achieved with a split-thickness skin graft using the scalp as the donor site, which led to a quick recovery after the operation and satisfactory results in terms of aesthetics. This case suggests that a TPFF might be used as a flexible flap with low donor site morbidity for reconstructing cases of cochlear implant extrusion accompanied by a large full-layer scalp defect.

• Wind and Structures
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• v.1 no.1
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• pp.43-57
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• 1998

A three-degree-of-freedom base hinged assembly (BHA) for aeroelastic model tests of tall building was developed. The integral parts of a BHA, which consists of two perpendicular plane frames and a flexural pivot, enable this modeling technique to independently simulate building translational and torsional degree-of-freedom. A program of wind tunnel aeroelastic model tests of the CAARC standard tall building was conducted with emphasis on the effect of (a) torsional motion, (b) cross-wind/torsional frequency ratio and (c) the presence of an eccentricity between center of mass and center of stiffness on wind-induced response characteristics. The experimental results highlight the significant effect of coupled translational-torsional motion and the effect of eccentricity between center of mass and center of stiffness on the resultant rms acceleration responses in both along-wind and cross-wind directions especially at operating reduced wind velocities close to a critical value of 10. In addition, it was sound that the vortex shedding process remains the main excitation mechanism in cross-wind direction even in case of tall buildings with coupled translational-torsional motion and with eccentricity.