• Korean Journal of Agricultural and Forest Meteorology
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• v.12 no.4
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• pp.217-224
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• 2010

This study was carried out to quantify potential effects of the surrounding ocean on the observed air temperature at coastal weather stations in the Korean Peninsula. Daily maximum and minimum temperature data for 2001-2009 were collected from 66 Korea Meteorological Administration (KMA) stations and the monthly averages were calculated for further analyses. Monthly data from 27 inland sites were used to generate a gridded temperature surface for the whole Peninsula based on an inverse distance weighting and the local temperature at the remaining 39 sites were estimated by recent techniques in geospatial climatology which are widely used in correction of small - scale climate controls like cold air drainage, urban heat island, topography as well as elevation. Deviations from the observed temperature were regarded as the 'apparent' sea effect and showed a quasi-logarithmic relationship with the distance of each site from the nearest coastline. Potential effects of the sea on daily temperature might exceed $6.0^{\circ}C$ cooling in summer and $6.5^{\circ}C$ warming in winter according to this relationship. We classified 25 sites within the 10 km distance from the nearest coastline into 'coastal sites' and the remaining 15 'fringe sites'. When the average deviations of the fringe sites ($0.5^{\circ}C$ for daily maximum and $1.0^{\circ}C$ for daily minimum temperature) were used as the 'noise' and subtracted from the 'apparent' sea effects of the coastal sites, maximum cooling effects of the sea were identified as $1.5^{\circ}C$ on the west coast and $3.0^{\circ}C$ on the east and the south coast in summer months. The warming effects of the sea in winter ranged from $1.0^{\circ}C$ on the west and $3.5^{\circ}C$ on the south and east coasts.

• Spatial Information Research
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• v.12 no.2
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• pp.193-209
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• 2004

The purpose of this study is to analyze the service area of emergency medical centers using GIS-based spatial analysis methods in Seoul, focusing on the behaviour of patients on the choosing of emergency centers. For this analysis, six emergency centers were selected to collect data for the information on the addresses of patients from September to November hi 2003. Analysis on the service area, which was carried out by measuring the distribution of patients in terms of distance from emergency medical centers, clearly reveals that the majority of patients was located within or adjacent districts at the emergency medical center. However, the size of the primary service area f3r six emergency medical centers was much different, implying that the decision to visit specific emergency medical center by patients was closely related to the size, perception, and preference of the emergency medical center. Based on the results of the spatial characteristics of emergency medical service area, this research tries to construct the surface map of the emergency medical service level supplied by 32 regional emergency medical centers located in Seoul. Considering the levels of infrastructure for emergency medical centers, the coverage for the degree of supply of emergency medical service by each emergency medical center was constructed in terms of a distance decaying in the distribution of patients from emergency medical center imposing different weights on distance bands. Spatial overlay utilizing map algebra function was performed in order to calculate total supply level of emergency service. The results clearly show that spatial inequality exists in the supply levels of the emergency medical service among local areas of Seoul.

• Journal of Korea Multimedia Society
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• v.5 no.4
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• pp.458-467
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• 2002

There has been proposed many simplification algorithms for effectively decreasing large-volumed polygonal surface data. These algorithms apply their own cost function for collapse to one of fundamental simplification unit, such as vertex, edge and triangle, and minimize the simplification error occurred in each simplification steps. Most of cost functions adopted in existing works use the error estimation method based on distance optimization. Unfortunately, it is hard to define the local characteristics of surface data using distance factor alone, which is basically scalar component. Therefore, the algorithms cannot preserve the characteristic features in surface areas with high curvature and, consequently, loss the detailed shape of original mesh in high simplification ratio. In this paper, we consider the vector component, such as surface orientation, as one of factors for cost function. The surface orientation is independent upon scalar component, distance value. This means that we can reconsider whether or not to preserve them as the amount of vector component, although they are elements with low scalar values. In addition, we develop a simplification algorithm based on half-edge collapse manner, which use the proposed cost function as the criterion for removing elements. In half-edge collapse, using one of endpoints in the edge represents a new vertex after collapse operation. The approach is memory efficient and effectively applicable to the rendering system requiring real-time transmission of large-volumed surface data.

• Journal of Advanced Navigation Technology
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• v.22 no.2
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• pp.49-56
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• 2018

As the energy generated by earthquake, tsunami, etc. propagates through the air and disturbs the electron density in the ionosphere, the perturbation can be detected by analyzing the ionospheric delay in satellite signal. The electron density in the ionosphere is affected by various factors such as solar activity, latitude, season, and local time. To distinguish from the anomaly, therefore, it is required to inspect the normal trend of the ionosphere. Also, as the perturbation magnitude diminishes by distance it is necessary to develop an appropriate algorithm to detect long-distance disturbances. In this paper, normal condition ionosphere trend is analyzed via IONEX data. We selected monitoring value that has no tendency and developed an algorithm to effectively detect the long-distance ionospheric disturbances by using the lasting characteristics of the disturbances. In the end, we concluded the $2^{nd}$ derivative of ionospheric delay would be proper monitoring value, and the false alarm with the developed algorithm turned out to be 1.4e-6 level. It was applied to 2011 Tohoku earthquake case and the ionospheric disturbance was successfully detected.

• Journal of Korean Society of Water and Wastewater
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• v.19 no.4
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• pp.462-472
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• 2005

This study was carried out to suggest the plans for installation of rural sewage treatment facilities through the analysis of these facilities installed in Chungchongnam-do Province. About 5% of all installation was carried out by the department of wastewater and related environment problems and the other case was carried out by the department of construction or residence. In wastewater caused by 250 and 300 persons, facilities capacity do not exceed about $50m^3/d$, caused by 2,500 and 3,000 persons, $500m^3/d$. Advanced sewage treatment process were first needed in the discharge area where affected the water environment greatly. However, in carrying out the water quality pollutant of the total amount management system in the other areas, they should be driven only over the scale of pollutant quota object facilities standard. Rural sewage must be included in the special accounts according to the regulations of local government, and sewage treatment cost should be collected to manage. Installation type uses integrating joint treatment method in case the distance among villages is short or one treatment facility independently.

• Earthquakes and Structures
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• v.3 no.2
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• pp.169-180
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• 2012

The performance of pure friction isolation system with respect to the frequency bandwidth of excitation and the predominant frequency is investigated. A set of earthquake ground motions (artificial as well as recorded [with different combinations of magnitude-distance and local site geology]) is considered for investigating effectiveness of pure friction isolators. The results indicate the performance of pure friction base isolated system does not only depend upon coefficient of friction and mass ratio but the stick-slip behaviour depends upon the frequency content of the excitation as well. Slippage prevails if the excitation frequency lies in a suitable frequency range. This range widens with increasing mass ratio. For larger mass ratios, the sliding effect is more pronounced and the maximum acceleration response is further reduced in the neighbourhood of frequency ratio (${\omega}/{\omega}_n$) of unity. The pure friction isolation system is effective in the case of broadband excitations only and that too, in the acceleration sensitive range of periods. The pure friction system is not effective for protection against narrow band motions for which the system response is quasi-periodic.

• Journal of The Korean Society of Integrative Medicine
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• v.3 no.3
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• pp.43-47
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• 2015

Purpose : The aim of this study was to report a follow-up study on the prognosis following the arthrocentsis for the painful temporomandibular dysfunction not responsible to the conservative splint therapies. Arthrocentsis of TMJ is a simple precedure that can be performed in the out-patient clinic under the local anesthesia without any reported complications. Method : Seventy patients had been followed after the arthrocentsis for over 6 months. Maximum mouth opening, TMJ pain, TMJ noise, and their changes by time were examined and compared statistically. The effectiveness of the treatment was evaluated in terms of the postoperative range of maximal mouth opening (MMO) and the degree of postoperative pain score. Predictors which was analyzed were age, duration of painful locking, MMO, the degree of pain, preoperative clicking and the amounts of irrigation fluid. Result : The result of this study were as follow; 1) Mouth opening was improved from 32.6 mm to 42.4 mm in the maximum inter-incisal distance. 2) TMJ pain was decreased in 45.7%. 3) TMJ clicking and noise disappeared in 60.0%, but recurred in 40.0%. Conclusion : Amounts of irrigated solution recovered to normal MMO and the appeareance of perioperative clkicking may be predictors of the successful results of arthrocenetesis of ADD without reduction of TMJ.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.1036-1041
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• 2003

Non-destruction examinations are required in medical sciences and various engineering now. We wish to emulate the examinations in very simplified experiments. It is an educational program. We show a neural network analysis to predict the locations of a sound-source or a body irradiated by sound-waves in audio-region. The sound is an interest flux, and it enables to clear local-structures in a non-transparent space. However, the sound-propagation equations are not solved easily, therefore, we consider to adopt multi-layer neural-networks instead of the direct solutions. We used detected intensities and coordinates for input data and teaching data. A neural network learned them. The neural-network analysis decomposed the distance of 50cm. The resolution is rather rough; however, it is caused by the limitation of our equipments. Since there is no problem in the neural network processing, if we could revise experiments, then, progress of the resolution would be got. Thus, the proposed method functioned as an educational and simplified non-destruction examination.

• Structural Engineering and Mechanics
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• v.73 no.6
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• pp.651-666
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• 2020

In this study, the spatial variation mechanisms of large far-field earthquakes at engineering scales are first investigated with data from the 2008 Ms 8.0 Wenchuan earthquake. And a novel 'coherency cut-off frequency' is proposed to distinguish the spatial variations in ground motions in the low-frequency and high-frequency ranges. Then, a practical piecewise coherency model is developed to estimate and characterize the spatial variation in earthquake ground motions, including the effects of source-to-site distances, site conditions and neighboring topography on these variations. Four particular earthquake records from dense seismograph arrays are used to investigate values of the coherency cut-off frequency for different source-to-site distances. On the basis of this analysis, the model is established to simulate the spatial variations, whose parameters are suitable for both near- and far-field earthquake conditions. Simulations are conducted to validate the proposed model and method. The results show that compared to the existing models, the proposed model provides an effective method for simulating the spatial correlations of ground motions at local sites with known source-to-site distances.

• Journal of Advanced Marine Engineering and Technology
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• v.39 no.6
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• pp.609-613
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• 2015

In this study, the experiments are performed to investigate the local heat transfer and pressure drops of developed turbulent flows in the diverging square channels along the axial distance. The square divergent channels are manufactured with a fixed rib height (e) = 10 mm. Four different parallel angled ribs ($a=30^{\circ}$, $45^{\circ}$, $60^{\circ}$, and $90^{\circ}$) are placed on the channel's one-sided wall only. TThe measurement are conducted within the range of Reynolds numbers from 22,000 to 79,000. The results show that a rib angle-of-attack of $45^{\circ}$ produces the best heat-transfer performance.