• Proceedings of the KIEE Conference
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• 2001.07c
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• pp.1921-1923
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• 2001

In this work, an array of resistance temperature detector(RTD) was fabricated inside the microchannel in order to investigate in-situ flow characteristics. A rectangular straight microchannel, integrated with RTD's for temperature sensing and a heat source for generating the temperature gradient along the channel. were fabricated with the dimension of $200{\mu}m(W){\times}{\mu}m(D){\times}$48mm(L), while RTD measured precise temperatures at the inside-channel wall. 4" $525{\pm}25{\mu}m$ thick P-type <100> Si wafer was used as a substrate. For the fabrication of RTDs. 5300$\AA$ thick Pt/Ti layer was sputtered on a Pyrex glass wafer. Finally, glass wafer was bonded with Si wafer by anodic bonding, therefore RTD was located inside the microchannel. The temperature distribution inside the fabricated microchannel was obtained from 4 point probe measurements and Dl water is used as a working fluid. Temperature distribution inside the microchannel was measured as a function of mass flow rate and heat flux. As a result, precise temperatures inside the microchannel could be obtained. In conclusion, this novel temperature distribution measurement system will be very useful to the accurate analysis of the flow characteristics in the microchannel.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.07b
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• pp.976-979
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• 2003

In this study, we formed the 2-dimensional holographic grating in order to mamufactured 2-dimensional photonic crystal in amorphous $As_{40}Ge_{10}Se_{15}S_{35}$ and $Ag/As_{40}Ge_{10}Se_{15}S_{35}$ thin film which have the excellent optical sensetivity using by He-Ne laser(632.8nm). The intensity of incident beam was 2.5mW and incident angle that $2{\theta}$ is $20^{\circ}$. We formed the holographic grating after had formed the 1-dimansional holographic grating and then rotate the sample. We confirmed that 2-dimensional holographic grating result of the figure of diffracted beam and AFM(Atomic Forced Microcopy) image.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.39 no.7
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• pp.16-25
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• 2002

This paper presents a methodology and application for extracting parasitic inductances in a multi-level interconnect semiconductor structure by a numerical technique. In order to calculate the parasitic inductances, the distrubution of electric potential and current density in the metal lines are calculated by finite element method (FEM). Thereafter, the magneto-static energy caused by the current density in metal lines was calculated. The result of simulation is compared with the result of Grover equation about analytic simple structures, and 4 bit ROM array with a dimension of $13{\times}10.25{\times}8.25{\mu}m^3$ was simulated to extract the parasitic inductnaces. In this calculation, 6,358 nodes with 31,941 tetrahedra were used in ULTRA 10 workstation. The total CPU time for the simulation was about 150 seconds, while the memory size of 20 MB was required.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.11
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• pp.1047-1053
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• 2011

In this paper, we proposed an HF-band wireless power transfer system with adaptive frequency control circuit for efficiency enhancement in a short range. In general, a wireless power transfer system shows an impedance mismatching due to a reflected impedance, because a coupling coefficient is varied with respect to separation distance between two resonating loop antennas. The proposed method can compensate this impedance mismatching by varying input frequency of a voltage-controlled oscillator adaptively with respect to separation distance. Therefore, transmission efficiency is enhanced in a short distance, where large impedance mismatch occurs. The adaptive frequency circuit consists of a directional coupler, a detector, and a loop filter. In order to demonstrate the performance of the proposed system, a wireless power transfer system with adaptive frequency control circuits is designed and implemented, which has a pair of loop antennas with a dimension of 30${\times}$30 $cm^2$. From measured results, the proposed system shows enhanced efficiency performance than the case without adaptive frequency control.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.7-12
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• 2003

When the wind turbine is used in cold regions, the mechanical properties and dimension stability of the blade will be changed. The proposal of this paper is to test the durability of the blade for wind turbine. It is necessary to select the most comfortable materials and fabrication processes for more stable wind turbine blade in cold regions. To select the most comfortable materials and processes, the static strength has to know through the tensile static tests at the severe condition as cold regions. First, the tensile static specimens made by RIM (Resin injection molding) process & vacuum bagging process with reinforcement materials and resin. Tensile static tests were carried out on three laminate lay-ups (carbon prepreg, carbon fiber dry fabric and glass fiber dry fabric) at different test temperature($24^{\circ}$, $-30^{\circ}$), determining properties such as the mechanical strength, stiffness and strain to failure. At different test temperature, in order to test the tensile strengths of these specimens used the low temperature chamber. Next, the results of this test were compared with each other. Finally, the most comfortable materials and fabrication processes can select based on these results. The results show the changes in the static behavior of three laminate lay-ups at different test temperatures. At low temperatures, the static strengths are higher than the ones at room temperature.

• The Journal of the Korea Contents Association
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• v.12 no.12
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• pp.597-604
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• 2012

In order to actualize the third dimension form, hologram is coming to attention because it has no restriction on viewing position and is capable of natural visual expression. Although hologram technology is the best method to embody 3D image without glasses, it is not commercialized due to several technological problems. Currently used hologram technology in concerts or exhibitions are images flashed on a 2-dimensional transparent screen by HD projectors which is similar to hologram technology, not truly same. In this research, we make 3D contents for Holographic projection and use these contents to present art that can interact with spectators. As a result of the exhibition, attendance showed satisfaction on inspection form, allowing spectators to move around the screen and view it both sides; moreover, they were enterprising to interact with the videos played according to their movements. Therefore, we are able to implement a sensible and spatio-temporal artwork along with interesting space production and represent a intimate and interactive space with the public.

• The Journal of Korean Physical Therapy
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• v.26 no.2
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• pp.82-89
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• 2014

Purpose: This study was conducted in order to develop an instrument for the Korean Osteoarthritis Impact Measurement scale (KAIMS) in hip and knee osteoarthritis patients. Methods: A sample of 426 subjects was recruited in Ulsan metropolitan city (six hospitals and clinics) and Andong city (five hospitals and clinics) from June 2010 to May 2011. Item internal consistency and item discriminant validity were analyzed on the item-level, and floor (%) and ceiling (%) effect were analyzed on the scale-level. Exploratory factor analysis was performed for construction of items in the KAIMS instrument; confirmative factor analysis was also performed to test the fit of the model. Results: In 426 respondents, age was 64.3 years. The reliability for r coefficient 0.90 (mobility) and 0.89 (pain and stiffness) (Cronbach's alpha 0.95, 0.95 respectively) was high in the test-retest, and there was no significant difference in paired t-test (p>0.05). Item internal consistency (${\alpha}=0.92$, ${\alpha}=0.87$ respectively) was also high. It was constructed of two factors (mobility, pain and stiffness dimension) and nine items in explanatory factor analysis; results of confirmatory factor analysis also indicated that the dimensional structure model was fitted well in the test of model fit (${\chi}^2=83.83$, df=26, p=0.000; RMR=0.05; GFI=0.96; AGFI=0.83). Conclusion: In conclusion, the results of this study showed that the KAIMS that was developed was a reliable and valid instrument for measurement of osteoarthritis (OA) patients. We recommend further research for additional development of the instrument on OA in Korea.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.11 no.1
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• pp.12-19
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• 2000

Background and Objectives : Dysphonia may be secondary to many different type of benign vocal cord lesions such as vocal polyp, vocal nodule, Reinke's edema, and intracordal cyst. Diagnosis and treatment of intracordal cysts are more difficult than other benign vocal cord lesions. But postoperative voice analysis of intracordal cyst have rarely been reported in the literature. The purpose of this study is to analyze aerodynamic and acoustic results and videostroboscopic findings before and after laryngomicrosurgery. Materials and Methods : We reviewed the pre and post-operative voice analysis results and videostroboscopic findings of 15 surgically treated patients of intracordal cysts at Severance hospital from Jun. 1997 to Nov. 1999 retrospectively. They were diagnosed with videostroboscopic findings, surgical findings, and pathologic reports. Their pre and post-operative speech were analyzed with MDVP(Multi Dimension Voice Analysis Program) of CSL(Computerized Speech Lab) and Aerophone II. Their pre and post-operative mucosal wave of true vocal cord was analyzed with videostroboscopy. In order to compare this results with normal group, 10 of normal persons were evaluated with same methods. Results : After the operation, mucosal wave of true vocal cord was improved in all patients. Postoperative acoustic and aerodynamic results were improved in almost parameters, but they did not reach the normal value. Conclusions : Videostroboscopy was essential in diagnosing intracordal cysts. By comparing the acoustic and aerodynamic results and video-stroboscopic findings before and after the laryngomicrosurgery, postoperative vocal function was defined more accurately and objectively. Almost parameters may be useful in assessing the quantitative changes in vocal quality before and after the laryngomicrosurgery.

• Journal of the Korean Society of Propulsion Engineers
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• v.1 no.2
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• pp.91-102
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• 1997

In order to evaluate the effects of aging on the ignition performance, pyrotechnic igniters were separated from twelve-year-old, fifteen-year-old, and sixteen-year-old live rocket motors. The characteristic values of the ignition material were measured, and the firing tests of the igniters were performed. The moisture content, the outer dimension, the crush strength, the thermal decomposition characteristics, and the heat of formation the B/$KNO_3$ ignition pellet were measured. The crush strength was increased and the heat of formation was reduced as aged, but no change was detected for other characteristic values. The burning test results of the igniter pellet in the closed bomb and the inert motor showed that the burning rate of the ignition pellet was increased by 10%, and the integration of pressure $P_t$ of the p-t curve was reduced by 15% for aged samples. It was inferred that the burning rate was increased as the crack was appeared in the pellet and $P_t$ could be proportionally decreased with the heat of explosion.

• Journal of the Korean Society of Marine Environment & Safety
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• v.22 no.5
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• pp.576-582
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• 2016

To cope with international regulations, such as Energy Efficiency Design Index (EEDI), Ship Energy Efficiency Management Plan (SEEMP) and so forth, and to enforce limitations on $CO_2$ emissions, green-ship technology to lower fuel consumption has been actively researched, and the development of an energy-saving device (ESD) is being pursued. In order to design an ESD for small and medium-sized domestic vessels, an analysis on flow characteristics has been performed in the present study. Through a model test and numerical analyses, the characteristics of flow around the stern bilge and bulb have been compared to improve wake quality and resistance performance. As a result of these comparisons and analyses, a vertical plate has been adopted,, as a new ESD. Design criteria for the proposed ESD are also suggested. By applying this new ESD, it is expected that the total resistance and average nominal wake can be reduced by 3.04 % and 18.8 %, respectively.