• Journal of Korean Tunnelling and Underground Space Association
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• v.2 no.3
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• pp.37-45
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• 2000

In recent years two reflection methods, i.e. GPR and seismic Impact-Echo, are usually performed to obtain the information about tunnel lining structures composed of concrete lining, shotcrete, water barrier, and voids at the back of lining. However, they do not lead to a desirable resolution sufficient for the inspection of tunnel safety, due to many problems of interest including primarily (1) inner thin layers of lining structure itself in comparison with the wavelength of source wavelets, (2) dominant unwanted surface wave arrivals, (3) inadequate measuring strategy. In this sense, seismic physical modeling is a useful tool, with the use of the full information about the known physical model, to handle such problems, especially to study problems of wave propagation in such fine structures that are not amenable to theory and field works as well. Thus, this paper deals with various results of seismic physical modeling to enable to show a possibility of detecting the inner layer boundaries of tunnel lining structures. To this end, a physical model analogous to a lining structure was built up, measured and processed in the same way as performed in regular reflection surveys. The evaluated seismic section gives a clear picture of the lining structure, that will open up more consistent direction of research into the development of an efficient measuring and processing technology.

• Journal of Korean Society of Environmental Engineers
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• v.31 no.11
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• pp.1033-1040
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• 2009

One thing to note in cyclone operation and design is to minimize the pressure drop with the enhancement of the efficiency of dust collection. This can be facilitated by the detailed resolution of complex fluid flow occurring inside a cyclone. To this end, the main objective of this study was to obtain the detailed fluid dynamics by the development of a reliable computation method and thereby to figure out the physics of dust collection mechanism for more extreme environment caused by high temperature and pressure condition. First of all, the computer program developed was evaluated against experimental result. That is, the numerical calculation predicts well the data of experimental pressure drop as a function of flow rate for the elevated pressure and temperature condition employed in this study. The increase of pressure and temperature generally affects significantly the collection efficiency of fine particle but the effect of pressure and temperature appears contrary each other. Therefore, the decrease of collection efficiency caused by the high operating temperature mainly due to the decrease of gaseous density can be remedied by increase of operating pressure. After the evaluation of the program, a series of parametric investigations are performed in terms of major cyclone design or operating parameters such as tangential velocity and vortex finder diameter for dusts of a certain range of particle diameters, etc. As expected, tangential velocity plays the most important effect on the collection efficiency. And the efficiency was not affected significantly by the change of the length of vortex finder but the diameter of vortex finder plays an important role for the enhancement of collection efficiency.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.10
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• pp.1081-1089
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• 2005

In order to examine the application feasibility of Orimulsion fuel in a commercial boiler using heavy fuel oil, a numerical and experimental research efforts have been made especially to figure out the fundamental combustion characteristics of this fuel in a small-scale boiler. One of the notable combustion features of Orimulsion fuel is the delayed appearance of flame location with the flame shape of rather broad distribution, which is found experimentally and confirmed by numerical calculation. This kind of flame characteristics is considered due to the high moisture content included inherently in the process of Orimulsion manufacture together with micro-explosion by the existence of fine water droplets. In order to investigate the effect on the combustion characteristics of Orimulsion, a series of parametric investigation have been made in terms of important design and operational variables such as injected amount of fuel, types of atomization fluid, and phonemenological radiation model employed in the calculation, etc. The delayed feature of peak flame can be alleviated by the adjustment of the flow rate of injected fuel and the generating features of CO, $SO_2$ and NO gases are also evaluated in the boiler. When the steam injection as atomizing fluid is used, the combustion process is stabilized with the reduced region of high flame temperature. In general, the calculation results are physically acceptable and consistent but some refinements of phenomenological models are necessary for the better resolution of pollutant formation. From the results of this small-scale Orimulsion boiler, it is believed that a number of useful information are obtained with the working computer program for the near future application of Orimulsion fuel to a conventional boiler.

• Journal of the Mineralogical Society of Korea
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• v.20 no.3
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• pp.203-212
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• 2007

Mineral compositions of 89 Yellow Sea surface sediments collected at the second cruise in 2001, were determined using the high resolution X-ray diffractometer and Siroquant v.3.0 program. Yellow Sea surface sediments are composed of major minerals (quartz 57.8%, plagioclase 16.0% and alkali feldspar 10.0%), clay minerals, and calcite. Illite (8.7%) is the most abundant clay mineral, chlorite (2.6%) is the second, and kaolinite (0.6%) is few. however smectite is not detected. Quartz content is very high around the margin of the Yellow Sea, however is very low along the northwest to southeast direction extending from southeast of Sandong Peninsula to southwest of Jeju Island. It has similar distribution pattern with that of coarse sediment (sand). The coarse sediment, is mainly consisted of quartz, may be much supplied from the eastern part and southwestern part of the Yellow Sea. Illite distribution pattern is opposite to that of quartz. It is similar to those of clay and mud particles, therefore it can be suggested that fine sediment may be largely supplied from the northwestern part of the Yellow Sea. It is necessary to continue this kind of investigation, because it is difficult to interpret the sediment provenance of the Yellow Sea only from the result of this study.

• Tuberculosis and Respiratory Diseases
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• v.50 no.6
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• pp.732-739
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• 2001

Systemic lupus erythematosus frequently has thoracic involvement among connective tissue diseases. One of the pleuropulmonary manifestations is diffuse interstitial lung disease including nonspecific interstitial pneumonia(NSIP). NSIP is a newly classified disease among interstitial lung diseases. Systemic lupus erythematosus has a better prognosis than usual interstitial peumonia(UIP) and responds well to steroids. In this report, a 34 year-old woman who complained of a dry cough, and exertional dyspnea for 2 months is described. The chest X-ray showed fine reticular opacities and a mild honeycomb appearance in both basal lungs. High resolution computed tomography(HRCT) showed bilateral patchy areas of ground-glass attenuation and a mild honeycomb appearance in the subpleural of both the lower and the middle portion of the lung fields. An open lung biopsy showed prominent lymphocytic interstitial inflammation and fibrosis with small areas with a honeycomb appearance. This case was diagnosed as NSIP associated with systemic lupus erythematosus and was managed with oral steroids. Here we report a case of nonspecific interstitial pneumonia associated with systemic lupus erythematosus confirmed by HRCT and an open lung biopsy with a review of the relevant literature.

• The Bulletin of The Korean Astronomical Society
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• v.42 no.1
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• pp.40.3-41
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• 2017

Korea Astronomy and Space Science Institute The observation of particles and waves using a single satellite inherently suffers from space-time ambiguity. Recently, such ambiguity has often been resolved by multi-satellite observations; however, the inter-satellite distances were generally larger than 100 km. Hence, the ambiguity could be resolved only for large-scale (> 100 km) structures while numerous microscale phenomena have been observed at low altitude satellite orbits. In order to resolve those spatial and temporal variations of the microscale plasma structures on the topside ionosphere, SNIPE mission consisted of four (TBD) nanosatellites (~10 kg) will be launched into a polar orbit at an altitude of 700 km (TBD). Two pairs of satellites will be deployed on orbit and the distances between each satellite will be from 10 to 100 km controlled by a formation flying algorithm. The SNIPE mission is equipped with scientific payloads which can measure the following geophysical parameters: density/temperature of cold ionospheric electrons, energetic (~100 keV) electron flux, and magnetic field vectors. All the payloads will have high temporal resolution (~ 16 Hz (TBD)). This mission is planned to launch in 2020. The SNIPE mission aims to elucidate microscale (100 m-10 km) structures in the topside ionosphere (below altitude of 1,000 km), especially the fine-scale morphology of high-energy electron precipitation, cold plasma density/temperature, field-aligned currents, and electromagnetic waves. Hence, the mission will observe microscale structures of the following phenomena in geospace: high-latitude irregularities, such as polar-cap patches; field-aligned currents in the auroral oval; electro-magnetic ion cyclotron (EMIC) waves; hundreds keV electrons' precipitations, such as electron microbursts; subauroral plasma density troughs; and low-latitude plasma irregularities, such as ionospheric blobs and bubbles. We have developed a 6U nanosatellite bus system as the basic platform for the SNIPE mission. Three basic plasma instruments shall be installed on all of each spacecraft, Particle Detector (PD), Langmuir Probe (LP), and Scientific MAGnetometer (SMAG). In addition we now discuss with NASA and JAXA to collaborate with the other payload opportunities into SNIPE mission.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.3
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• pp.503-510
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• 2006

Readout circuit is to convert signal occurred in a defector into suitable signal for image signal processing. In general, it has to possess functions of impedance matching with perception element, amplification, noise reduction and cell selection. It also should satisfies conditions of low-power, low-noise, linearity, uniformity, dynamic range, excellent frequency-response characteristic, and so on. The technical issues in developing image processing equipment for focal plane way (FPA) can be categorized as follow: First, ultraviolet (UV) my detector material and fine processing technology. Second, ReadOut IC (ROIC) design technology to process electric signal from detector. Last, package technology for hybrid bonding between detector and ROIC. ROIC enables intelligence and multi-function of image equipment. It is a core component for high value added commercialization ultimately. Especially, in development of high-resolution image equipment ROIC, it is necessary that high-integrated and low-power circuit design technology satisfied with design specifications such as detector characteristic, signal dynamic range, readout rate, noise characteristic, ceil pitch, power consumption and so on. In this paper, we implemented a $8\times8$ FPA prototype ROIC for reduction of period and cost. We tested unit block and overall functions of designed $8\times8$ FPA ROIC. Also, we manufactured ROIC control and image boards, and then were able to verify operation of ROIC by confirming detected image from PC's monitor through UART(Universal Asynchronous Receiver Transmitter) communication.

• Journal of the Korean Institute of Intelligent Systems
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• v.26 no.1
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• pp.1-8
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• 2016

The Korea Meteorological Administration has operated the Automatic Weather Stations, of the average 13 km horizontal resolution, to observe rainfall. However, an additional RADAR network also has been operated in all-weather conditions, because AWS network could not observed rainfall over the sea. In general, the rain rate is obtained by estimating the relationship between the radar reflectivity (Z) and the rainfall (R). But this empirical relationship needs to be optimized on the rainfall over the Korean peninsula. This study was carried out to optimize the Z-R relationship in the summer of 2014 using a parallel Micro Genetic Algorithm. The optimized Z-R relationship, $Z=120R^{1.56}$, using a micro genetic algorithm was different from the various Z-R relationships that have been previously used. However, the landscape of the fitness function found in this study looked like a flat plateau. So there was a limit to the fine estimation including the complex development and decay processes of precipitation between the ground and an altitude of 1.5km.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.38 no.2
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• pp.227-235
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• 2018

In this study, we developed a relational formula for observing high - resolution rainfall using vehicle rain sensor. The vehicle rain sensor consists of eight channels. Each channel generates a sensor signal by detecting the amount of rainfall on the windshield of the vehicle when rainfall occurs. The higher the rainfall, the lower the sensor signal is. Using these characteristics of the sensor signal generated by the rain sensor, we developed a relational expression. In order to generate specific rainfall, an artificial rainfall generator was constructed and the change of the sensor signal according to the variation of the rainfall amount in the artificial rainfall generator was analyzed. Among them, the optimal sensor channel which reflects various rainfall amounts through the sensitivity analysis was selected. The sensor signal was generated in 5 minutes using the selected channel and the representative values of the generated 5 - minute sensor signals were set as the average, 25th, 50th, and 75th quartiles. The calculated rainfall values were applied to the actual rainfall data using the constructed relational equation and the calculated rainfall amount was compared with the rainfall values observed at the rainfall station. Although the reliability of the relational expression was somewhat lower than that of the data of the verification result data, it was judged that the experimental data of the residual range was insufficient. The rainfall value was calculated by applying the developed relation to the actual rainfall, and compared with the rainfall value generated by the ground rainfall observation instrument observed at the same time to verify the reliability. As a result, the rain sensor showed a fine rainfall of less than 0.5 mm And the average observation error was 0.36mm.

• Journal of Veterinary Clinics
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• v.27 no.1
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• pp.88-92
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• 2010

An 11-year-old, spayed female, weighing 10 kg miniature Schnauzer was admitted for abdominal distension, anorexia, pollakiuria, and constipation. A large, homogeneous fat opacity mass was identified in the retroperitoneum and pelvic cavity on the abdominal survey radiography. The mass displaced the descending colon peripherally and ventrally, and the urinary bladder ventrally. On the abdominal ultrasonographic examination, the mass was uniformly hyperechoic with a coarse internal echo texture and had outer hyperechoic capsule, and it showed homogeneously same attenuation (-180 ~ -110 HU) as adjacent fat on the computed tomography. There was no evidence of invasion into the surrounding structures or organs. Cytological findings from fine needle aspirates were numerous sheets and clusters of adipocytes. The dog showed complete resolution of clinical signs after surgical resection of the mass. The mass was confirmed as simple lipoma through histopathological examination.