• Journal of Korea Water Resources Association
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• v.45 no.4
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• pp.419-430
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• 2012

Due to the calculation difficulty on the hydraulic and hydrologic analysis for road drainage facilities design, these analysis techniques are not applicable. This study's result are development of minutely rainfall-intensity equation suitable for road drainage area, verification of rainfall-runoff model joining kinematic wave theory for road drainage area, computational model based GUI for road surface drainage facilities spacing and culvert's size decision and various road drainage channel design. Applicable test on the developed model is proceed, result that in case of road surface dranage facilities spacing is narrower 6~65% than present spacing calculation method, in other case of road cross dranage facilities size is bigger 6~140% than present size decision method.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.13 no.2
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• pp.46-54
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• 1999

In recent years, the electromagnetic enviroments are varied with the increase of power consumption and the spread of hoosehold electric appliances. Most of the interests to date have concentrated in the area of human health effects associated with exposure to power frequency electric and rmgretic fields, and thus the precise measurement and analysis are required. In this paper, the measurements and analysis of the extremdy low frequency(ElF) electric and magnetic fields produced by actual 22.9[kV] distribution lines were performed. The experiIrents have been carried rot by lateral rrofile, and the thooretical analyses were made by use of FIELDS program fer the sake of comparison with the experimental data. Electric and magnetic field intensity were strong under power distrib.rticn lines, and were inversely proportional to lateral distance. The pufiles of electric and magnetic fields were M and $\bigcap$ shapes, respectively. and the rreasured data were good in agreemnt with the thooretical results. Both the electric and magnetic field intensity were iocreased with increasing the measurement height.height.

• Physical Therapy Korea
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• v.18 no.3
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• pp.94-102
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• 2011

The purpose of this study was to review existing assessment tools for patients with low back pain and improve them through combination. A total of 314 patients with low back pain participated. Their condition was assessed using the Oswestry Disability Questionnaire (ODQ), the Quebec Back Pain Disability Scale (QBPD), and the Back Pain Functional Scale (BPFS). Rasch analysis was applied to identify inappropriate items, item difficulties, and the separation index. In this study, the 'sex life' item of the ODQ (10 items) and the 'sleeping' item of the BPFS (12 items) showed misfit statistics, whereas all items of the QBPD (20 items) were appropriate. After combining the ODQ, QBPD and BPFS, Rasch analysis was applied. The 'pain intensity', and the 'sex life' item of the ODQ and the 'throw a ball' item of QBPD showed misfit statistics. These 3 items were retained for further analysis. The remaining 42 combined ODQ-QBPD-BPFS items were arranged according to difficulty. For all subjects, the most difficult item was 'pain intensity', whereas the easiest was 'take food out of the refrigerator'. As the separation index of 42 combined ODQ-QBPD-BPFS was higher than that of the three questionnaires separately, difficulty of items varied with some need for rearrangement. The results of this study confirmed the possibility and need for a new back pain disability assessment tool, and produced one. Further study is needed to refine the questionnaire in consideration of psychosocial and occupational factors.

• Transactions of the Korean Society of Mechanical Engineers
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• v.16 no.7
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• pp.1373-1380
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• 1992

The local cyclic strain distribution near the crack tip has been investigated by the fine Dot Grid Strain Measurement Method, which had been suggested strain measurement method to resolve experimental difficulties by authors. It has been found that the magnitude of the local cyclic strain distribution(.DELTA..epsilon.$_{eq}$ )near a crack tip has been varied by the applied cyclic load level and material, but the shape of the local cyclic strain distribution near the crack tip has been experimentally scrarcely altered : that is .DELTA..epsilon.$_{eq}$ = .DELTA.A.f(.theta.). $r^{-1}$ . Consequently, the local cyclic strain field near the crack tip could be favorably characterized by a single parameter fatigue strain intensity factor .DELTA.A. In addition, with the viewpoint that .DELTA.A depends on material and load level, .DELTA.A has been applied to evaluate the fatigue crack propagation rate and usefulness of the result has been considered. As a result, it has been ascertained that .DELTA.A has been a useful parameter to evaluate the fatigue crack propagation rate.

• Korean Journal of Materials Research
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• v.4 no.4
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• pp.379-384
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• 1994

Room-temperature photoluminescent porous Si has been formed by etching Si wafer u-ith the solution of $HF:HNO_{3}: H_{2}O$=l : 5 : 10. We have observed photoluminescence(PL) spectra similar to those reported recently for porous-Si films formed by anodic etching with HF solutions. We have also investigated the dependence of PI, spectra on the etching time which was varied from 1 to 10 minutes. We found that 5-minute etching gave us the strongest PL intensity. We also found by atomic force microscopy( AFM) measurements that the surface fearure size became smaller for longer etching time and the average feature size of the etched Si wafer for 5-minute was about 1, 500~2, 000$\AA$. This indicates that the surface feature of the etched porous Si affects the PL intensity of the sample.

• The Journal of the Korea institute of electronic communication sciences
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• v.9 no.2
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• pp.155-160
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• 2014

In this paper, an algorithm using RGB-depth camera is proposed to detect smoke in interrior. RGB-depth camera, the Kinect provides RGB color image and depth information. The Kinect sensor consists of an infra-red laser emitter, infra-red camera and an RGB camera. A specific pattern of speckles radiated from the laser source is projected onto the scene. This pattern is captured by the infra-red camera and is analyzed to get depth information. The distance of each speckle of the specific pattern is measured and the depth of object is estimated. As the depth of object is highly changed, the depth of object plain can not be determined by the Kinect. The depth of smoke can not be determined too because the density of smoke is changed with constant frequency and intensity of infra-red image is varied between each pixels. In this paper, a smoke detection algorithm using characteristics of the Kinect is proposed. The region that the depth information is not determined sets the candidate region of smoke. If the intensity of the candidate region of color image is larger than a threshold, the region is confirmed as smoke region. As results of simulations, it is shown that the proposed method is effective to detect smoke in interior.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.39 no.6
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• pp.485-496
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• 2015

The present study presents experimental results on the characteristics of emission spectra of kerosene/air swirl flames. The aviation fuel Jet A-1, which is used for the liquid rocket engines of the Korea Space Launch Vehicle, is used with three different swirlers to investigate the swirl strength effects. The emission spectra from the flames are measured with a spectrometer as the swirl strength and combustion air temperature are varied. Chemiluminescence intensities of $OH^*$, $CH^*$ and $C_2{^*}$ are identified from the spectra. The chemiluminescence intensities from the kerosene flames show sensitivity to the swirl strength and are affected by changes in the combustion air temperature. Among the three radicals of interest, $C_2{^*}$ show the most significant changes in chemiluminescence intensity with the swirl strength and equivalence ratio. The intensity ratios $I_{OH^*}/I_{CH^*}$ and $I_{C_2{^*}}/I_{CH^*}$ are adequate for indicating changes in the equivalence ratio with the air and fuel mass flow rates, respectively.

• Bulletin of the Korean Space Science Society
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• 1992.10a
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• pp.21-21
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• 1992

The X-ray binary pulsar Her X-1 was observed with Ginga on 1988 August 28 during the orbital phase of 0.76 to 0.85 at the main-on phase of the 35 day cycle. During the observations the X-ray intensity varied by a factor of five or more on a time scale as short as 30 sec, due mostly to the soft X-ray absorption in the pre-eclipse phase. From the studies of pulse profiles and energy spectra, we revealed that there exists in the dipphase an unpulsed component which is "3% of the intensity at the non-absorbed high-level. We suggest that scattering of the source continuum by the optically thin hot corona is responsible for the unpoised component. In the spectral analysis, we find that the high-state non-absorbed spectra can be fitted by a power-law without absorption, and the spectra observed in the different abgorption states by two components of a power-law with the same photon index. An iron-K emission line is required in to the cases of fitting. The estimated equivalent width of the iron line varies from 0.18 to 0.51 key according to the change in the absorption column density along the line of sight. We suggest that the fluorescent iron line arises in a cool and relatively small region, like the Alfvensur face, and may be partially intercepted by the optically thick gas cloud passing across the line of sight.1 Korea Astronomy Observatorya The Institute of Space and Astronautical Science in Japan3 Korea Advanced Institute of Science and Technology

• Polymer(Korea)
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• v.24 no.2
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• pp.245-251
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• 2000

A blend system prepared from epoxy(EP) and polyurethane (PU) was investigated in terms of the contact angle and mechanical properties. The contents of EP/PU were varied within 100/0~100/60 phr in the presence of 20 phr DDM (4,4'-diamino diphenyl methane) as a curing agent for epoxy resin. Contact angle measurements were performed employing a Rame-Hart contact angle goniometer. Deionized water and diiodomethane were chosen as the testing liquids. In this work, Owens-Wendt and Wu's models using a geometric mean were studied to analyze the surface free energy of blend system. For the mechanical and toughening properties of the casting specimens, the critical stress Intensity factor ($K_{IC}$) and impact test were performed. Especially, the impact test was carried out at room and cryogenic temperatures. As a result, specific or polar component of the surface free energy of the blend system was largely influenced on the addition of the PU resulting in increasing the impact strength for the excellent low- temperature performance.

• Proceedings of the KIEE Conference
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• 2001.07c
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• pp.1732-1734
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• 2001

The purpose of this experiment was to develope Triggered Vacuum Switch(TVS) and to improve understanding of the high current vacuum arc phenomena in the TVS. The TVS has an array of rods of alternate polarity in which a fixed gap spacing is maintained between the rods. The cross section of each rod has trapezoidal shape. Breakdown of the TVS produced high current vacuum arc plasma. A spectroscopic measurement was performed over 20 kA peak current in the center of electrodes, in the vicinity of cathode, and outside electrodes. The electrode material tested was Fe. Measured Fe spectrum range was from 200 nm to 900 nm. Measurement result showed that over 90 percent of the charge states were FeII and the others were FeI and FeIII. The electron temperature was determined from the relative line intensity ratio methode of FeII system by assuming the local thermal equilibrium(LTE). The electron temperature at the center of electrodes was measured as 1.5 eV at 26 kA peak current. The electron temperature varied with its peak current. Intensity of spectrums is the highest in the vicinity of the cathode. Further we will also present study result of the diode phenomena in the TVS.