• Journal of Korea Spatial Information System Society
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• v.12 no.1
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• pp.95-99
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• 2010

Spatial information systems have developed in order to provide users with customized land information in u-City environments. The spatial information systems can detect spatial information for users anytime anywhere. Information which is analyzed by data mining techniques can be offered for other users. Therefore, we propose open map API-based prototype which utilizes frequent pattern mining technique. Proposed prototype can mine interesting trip routes and unknown attractions in location data of geophoto. Also, proposed prototype is the first attempt which analyzes spatial patterns can be represented on a map which is selected by users. Our prototype can be applied to the smart phone like mobile devices.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.1 no.1
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• pp.71-80
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• 1989

In this paper, the concept of the infinite element is applied to the linear wave diffraction and radiation problems. The hydrodynamic pressure forces are assumed to be inertially dominated, and viscous effects are neglected. The near field region surrounding the solid body is modelled using the conventional finite elements, and the far field region is represented using the infinite elements .In order to represent the scattered wave potentials in the far field region more accurately, the infinite elements are developed using special shape functions derived from the asymptotic expressions for the analytical eigenseries solution of the scattered waves. The system matrices of the infinite elements are constructed by performing the integration in the infinite direction analytically to achieve computational efficiency. Numerical analyses are carried out for vertical axisymmetric bodies to validate the infinite elements developed here. Comparisons with the results by other available numerical solution methods show that the present method using the infinite elements gives fairly good results. Numerical experiments are per-formed to determine the suitable location of the infinite elements and the appropriate size of the finite elements which directly affect accuracy and efficiency of the solution.

• Journal of Korea Spatial Information System Society
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• v.10 no.1
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• pp.41-49
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• 2008

This paper presents a data analysis method for the taxi telematics system which generates a greate deal of location history data. By the record consist of the basic GPS receiver-generated fields, device-added fields such as taxi operation status, and framework-attached fields such as matched link Identifier and position ratio in a link, each taxi can be represented by a state diagram. The transition and the state definition enable us to efficiently extract such information as pick-up time, pick-up distance, dispatch time, and dispatch distance. The analysis result can help to verify the efficiency of a specific taxi dispatch algorithm, while the analysis framework can invite a new challenging service including future traffic estimation, trajectory clustering, and so on.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.13 no.2
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• pp.24-41
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• 2010

Distributional characteristics of vascular plants and plants selection for revegetation in bare ground of lakeside was investigated in nine artificial lakes. The vascular plants were composed of 64 families, 194 genera, 268 species, 3 subspecies, 30 varieties, 3 forma, totaling 304 taxa. Dominant species of nine investigated areas were represented as Ambrosia trifida, Calystegia hederacea, Matricaria matricariodes, Xanthium italicum. Dominant species of three parts based on the location of artificial lakes were as follows:Ambrosia trifida, Bidens tripartita, Calystegia hederacea, Equisetum arvense, Setaria viridis, Spergula arvensis, Torilis japonica in northern part (Lake Paro and Soyang); Calystegia hederacea, Matricaria matricariodes, Rumex crispus, Xanthium italicum in middle part (Lake Chungju, Daecheong, Andong and Imha); and Ambrosia artemisiifolia, Bidens frondosa, Chenopodium glaucum, Miscanthus sinensis var. purpurascens, Persicaria pubescens, Setaria viridis in southern part(Lake Juam, Hapcheon and Jinyang). Among the 304 taxa, Korean endemic, endangered and rare plants were not investigated. The naturalized plants were 46 taxa, and life form was Th-$R_5-D_4$-e type. Above the results, Calystegia hederacea, Equisetum arvense, Xanthium italicum, Matricaria matricariodes, and Spergula arvensis were considered with proper species for revegetation in bare ground of lakeside in artificial lakes.

• Proceedings of the Korean Nuclear Society Conference
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• 1999.05a
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• pp.104-104
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• 1999

The local heat transfer coefficient is experimentally investigated for the reflux condensation in a countercurrent flow between the steam-air mixture and the condensate. A single vertical tube has a geometry which is a length of 2.4m, inner diameter of 16.56mm and outer diameter of 19.05mm and is made of stainless steel. Air is used as a noncondensible gas. The secondary side is installed in the form of coolant block around vertical tube and the heat by primary condensation is transferred to the coolant water. The local temperatures are measured at 15 locations in the vertical direction and each location has 3 measurement points in the radial direction, which are installed at the tube center, at the outer wall and at the coolant side. In three different pressures, the 27 sets of data are obtained in the range of inlet steam flow rate 1.348 -3.282kg/hr, of inlet air mass fraction 11.8 -55.0%. The local heat transfer coefficient increases as the increase of inlet steam flow rate and decreases as the decrease of inlet air mass fraction. As an increase of the system pressure, the active condensing region is contracted and the heat transfer capability in this region is magnified. The empirical correlation is developed represented with the 165 sets of local heat transfer data. As a result, the Jacob number and film Reynolds number are dominant parameters to govern the local heat transfer coefficient. The rms error is 17. 7% between the results by the experiment and by the correlation.

• Journal of the Society of Naval Architects of Korea
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• v.52 no.1
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• pp.88-95
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• 2015

For the frequency-domain spectral fatigue analysis, the probability density function of stress range needs to be estimated based on the stress spectrum only, which is a frequency domain representation of the response. The probability distribution of the stress range of the narrow-band spectrum is known to follow the Rayleigh distribution, however the PDF of wide-band spectrum is difficult to define with clarity due to the complicated fluctuation pattern of spectrum. In this paper, efforts have been made to figure out the links between the probability density function of stress range to the structural response of wide-band Gaussian random process. An artificial neural network scheme, known as one of the most powerful system identification methods, was used to identify the multivariate functional relationship between the idealized wide-band spectrums and resulting probability density functions. To achieve this, the spectrums were idealized as a superposition of two triangles with arbitrary location, height and width, targeting to comprise wide-band spectrum, and the probability density functions were represented by the linear combination of equally spaced Gaussian basis functions. To train the network under supervision, varieties of different wide-band spectrums were assumed and the converged probability density function of the stress range was derived using the rainflow counting method and all these data sets were fed into the three layer perceptron model. This nonlinear least square problem was solved using Levenberg-Marquardt algorithm with regularization term included. It was proven that the network trained using the given data set could reproduce the probability density function of arbitrary wide-band spectrum of two triangles with great success.

• Korean Journal of Bronchoesophagology
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• v.1 no.1
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• pp.116-121
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• 1995

The foreign bodies in the ENT field are very common disease. The kind of foreign bodies are closely related with our life style and was represented according to culture, habit, and economical status. We analyzed retrospectively 272 cases with foreign bodies in the upper aerodigestive tract and the external auditory canal which were diagnosed and managed at the Department of Otolaryngology Chungbuk National University from Jan. 1992 to Dec. 1994. We could divided 272 cases to the three groups; Group I was 212 cases(77.9%) that the patients had foreign bodies in the external auditory canal, nasal cavity, and pharynx which didn't need to be admitted, Group II was 57 cases(22%) that the patients had esophageal foreign bodies, and Group III was 3 cases(1.1%) that the patients had bronchial foreign bodies. The most prevalent age group was under 5 years old(32.3%). The overall ratio of male and female was 1.24 : 1, and the overall ratio of urban and rural ratio was 2.31 : 1. The ratio of esophageal foreign bodies and bronchial foreign bodies was 19 : 1. The incidence of sorts of foreign bodies in Group I was fish bone(41.07%), insect(25.9%), plastic bullet(8.0%), in order of frequency. The locations of foreign bodies in Group I was external auditory canal(36.8%), the tonsil(26.9%), nasal cavity(17.0%), tongue base(10.4%) in order of frequency. The incidence of sorts of foreign bodies in Group II was coin(49.1%), chicken bone(17.5%), fish bone(15.8%), in order of frequency. The main location of foreign bodies in Group II was the first narrowing(78.9%). In the Group III, the foreign bodies were corn, peanut, and apple. One patient who was arrived too late was died.

• Korean Journal of Microbiology
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• v.46 no.3
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• pp.255-261
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• 2010

The bacterial community structure associated with two marine sponges, Hyrtios sp. 604 and Callyspongia sp. 612 collected from the South Pacific Ocean were analyzed by 16S rDNA-denaturing gradient gel electrophoresis (DGGE). The phylogenetic analysis showed that the bacterial community associated with Hyrtios sp. 604 contained diverse bacterial groups such as Chloroflexi, Firmicutes, Cyanobacteria, Alphaproteobacteria, Gammaproteobacteria, Actinobacteria, and Acidobacteria. Callyspongia sp. 612 harbored Chloroflexi, Cyanobacteria, Alphaproteobacteria, and Gammaproteobacteria. Hyrtios sp. 604 belonging to genus Hyrtios known to produce natural products showed greater bacterial diversity than Callyspongia sp. 612. Phylum Actinobacteria was shown to be one of dominant bacterial groups in Hyrtios sp. 604. Although the same phyla of bacteria were found in both sponge species, the spongeassociated predominant bacterial groups differed between the two sponges with different chemical characteristics from the same geographical location. Uncultured bacteria represented over 90% of the bacteria diversity present in all bacterial communities of the sponges.

• Journal of Korean Society for Geospatial Information Science
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• v.18 no.4
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• pp.87-92
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• 2010

With recent localized heavy rain, the collapsing accident of the cut slopes occur repeatedly every year. The maintenance of the cut slopes is very crucial as the collapsing of cut slopes causes various calamities such as human causalities and sweeping away of the roads. By looking at the study of current situation of the cut slopes, designed for maintenance of cut slopes, the locations of the damaged districts are hard to figure out as they are represented through distance mark and longitude and latitude. In this paper has used NDGPS methods and VRS service through GPS signal corrections that are received by DGPS standard department to correctly analyze the exact location and the shape of the slope. The result of this analysis shows that both methods produce similar shape of the slope. Therefore, these two methods, NDGPS methods and VRS service, can be applied to other analysis of cut slopes in different areas.

• Journal of Gastric Cancer
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• v.17 no.4
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• pp.331-341
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• 2017

Purpose: This study aimed to evaluate the clinical significance of microscopic invasion to determine the adequate resection margin in early gastric cancer (EGC). Materials and Methods: A retrospective review was performed that included patients who underwent gastrectomy for clinical early gastric cancer (cEGC) at Seoul National University Hospital between January 2007 and December 2010. After subtracting the microscopic resection margin from the gross resection margin for each proximal or distal resection margin, microscopic invasion was represented by the larger value. Microscopic invasion and its risk factors were analyzed according to the clinicopathologic characteristics. Results: In total, 861 patients were enrolled in the study. Microscopic invasion of cEGC was $6.0{\pm}12.8mm$, and the proportion of patients with microscopic invasion ${\geq}0mm$ was 78.4%. In the risk group, tumor location, pT stage, and differentiation did not significantly discriminate the presence of microscopic invasion. The microscopic invasion of EGC-IIb was $13.9{\pm}16.8mm$, which was significantly greater than that of EGC-I. No linear correlation was observed between the overall tumor size and microscopic invasion (R=0.030). The independent risk factors for microscopic invasion ${\geq}20mm$ were EGC-IIb vs. EGC-I/IIa/IIc/III (odds ratio [OR], 3.103; 95% confidence interval [CI], 1.533-6.282; P=0.002) and male vs. female sex (OR, 1.655; 95% CI, 1.012-2.705; P=0.045). Conclusions: Male sex and EGC-IIb were independent risk factors for microscopic invasion ${\geq}20mm$. Examination of intraoperative frozen sections is highly recommended to avoid resection margin involvement, especially in cases of EGC-IIb.