• Journal of Korean Society of Coastal and Ocean Engineers
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• v.29 no.5
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• pp.217-227
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• 2017

The object of this study is to estimate the net volume transport and the residual flow that changed by space and time at southern part of Yeomha channel, Gyeonggi Bay. The cross-section observation was conducted at the mid-part (Line2) and the southern end (Line1) of Yeomha channel for 13 hours during neap and spring-tides, respectively. The Lagrange flux is calculated as the sum of Eulerian flux and Stokes drift, and the residual flow is calculated by using least square method. It is necessary to unify the spatial area of the observed cross-section and average time during the tidal cycle. In order to unify the cross-sectional area containing such a large vertical tidal variation, it was necessary to convert into sigma coordinate system by horizontally and vertically for every hour. The converted sigma coordinate system is estimated to be 3~5% error when compared with the z-level coordinate system which shows that there is no problem for analyzing the data. As a result, the cross-sectional residual flow shows a southward flow pattern in both spring and neap tides at Line2, and also have characteristic of the spatial residual flow fluctuation: it northwards in the main line direction and southwards at the end of both side of the waterway. It was confirmed that the residual flow characteristics at Line2 were changed by the net pressure due to the sea level difference. The analysis of the net volume transport showed that it tends to southwards at $576m^3s^{-1}$, $67m^3s^{-1}$ in each spring tide and neap tide at Line2. On the other hand, in the control Line1, it has tendency to northwards at $359m^3s^{-1}$ and $248m^3s^{-1}$. Based on the difference between the two observation lines, it is estimated that net volume transport will be out flow about $935m^3s^{-1}$ at spring tide stage and about $315m^3s^{-1}$ at neap tide stage as the intertidal zone between Yeongjong Island and Ganghwa Island. In other words, the difference of pressure gradient and Stokes drift during spring and neap tide is main causes of variation for residual current and net volume transport.

• Journal of Internet Computing and Services
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• v.16 no.2
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• pp.49-55
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• 2015

According to the statistics of traffic accidents over recent 5 years, traffic accidents during the night times happened more than the day times. There are various causes to occur traffic accidents and the one of the major causes is inappropriate or missing street lights that make driver's sight confused and causes the traffic accidents. In this paper, with smartphones, we designed and implemented a lane luminance measurement application which stores the information of driver's location, driving, and lane luminance into database in real time to figure out the inappropriate street light facilities and the area that does not have any street lights. This application is implemented under Native C/C++ environment using android NDK and it improves the operation speed than code written in Java or other languages. To measure the luminance of road, the input image with RGB color space is converted to image with YCbCr color space and Y value returns the luminance of road. The application detects the road lane and calculates the road lane luminance into the database sever. Also this application receives the road video image using smart phone's camera and improves the computational cost by allocating the ROI(Region of interest) of input images. The ROI of image is converted to Grayscale image and then applied the canny edge detector to extract the outline of lanes. After that, we applied hough line transform method to achieve the candidated lane group. The both sides of lane is selected by lane detection algorithm that utilizes the gradient of candidated lanes. When the both lanes of road are detected, we set up a triangle area with a height 20 pixels down from intersection of lanes and the luminance of road is estimated from this triangle area. Y value is calculated from the extracted each R, G, B value of pixels in the triangle. The average Y value of pixels is ranged between from 0 to 100 value to inform a luminance of road and each pixel values are represented with color between black and green. We store car location using smartphone's GPS sensor into the database server after analyzing the road lane video image with luminance of road about 60 meters ahead by wireless communication every 10 minutes. We expect that those collected road luminance information can warn drivers about safe driving or effectively improve the renovation plans of road luminance management.

• Journal of Korean Society of Forest Science
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• v.27 no.1
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• pp.5-14
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• 1975

Eroded sloping faces in hillsides including cut-bank slopes are liable to both surface erosion and land-slides and the key to control of these form of erosion lies with drainages of excessive run-off and dense vegetation establishment including surface mulching on the slopes. Micro-plots having $1.6m^2$ (1 metre in width and 1.6 metres in slope length, and 1:1.2 in gradient) of banking slopes on coarse sand soil are used to establish the order of magnititude of the difference in controlling of soil erosion and water runoff, and in rating of survival, performed on the repetetions of three-experiment plots consisted of such three levels as 90% (Dense), 70% (Moderate), and 50% Sparse of the density of the coarse straw-mat mulchings. The main results obtained may be summarized as follows: 1. The rates of surface runoff are calculated as 13.13% from the dense mulchings, 14.21% from the moderate mulchings, and 15.57% from the sparse mulchings respectively. 2. The total amounts of soil loss are measured as about 1.24 tons/ha. from the dense mulchings, about 1.33 tons/ha. from the moderate mulchings, and about 1.44 tons/ha. from the sparse mulchings respectively. The amounts of soil loss under these treatments are much lower than the standard of erosion in USDA (1939 Bennet). 3. Average numbers of germination by treatment are counted as 80 seedlings at the dense mulchings. 132 at the moderates and 121 at the sparse respectively. Large numbers of seedling are suppressed and died during the growing at the dense mulchings due to mainly mechanical obstruction. 4. Coarse straw-mat having about 70% of coverage density is the most suitable mulches in both soil erosion control and vegetation establishment. 5. The method of coarse straw-mat mulching is the most recommendable measure for establishing the vegetation cover with less soil erosion on the denuded gentle slopes in hillsides at present in Korea.

• Korean Journal of Environment and Ecology
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• v.23 no.5
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• pp.471-484
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• 2009

This study was carried out to classify vegetation structure on the deciduous forest at Namdeogyu area in Deogyusan National Park from May 2007 to September 2008 using the gradient analyses and phytosociological method. The vegetation was classified into Quercus mongolica community(Typical subcommunity, Rhododendron sehlippenbaehii-Q. mongolica subcommunity, Carex lanceolata-Q. mongolica subcommunity), Q. Serrata community(Typical subcommunity, Q. variabilis -Q. serrata subcommunity, Carpinus laxiflora - Q. serrata subcommunity), C. laxiflora community, Fraxinus mandshurica community and Corn us controversa community. Ecological characteristics such as species composition, layer structure, vegetation ratio, and the distribution of individual trees by DBH(diameter at breast height) were significantly different among communities. The order of important value of the forest community with DBH 2cm above plants was Q. mongolica(67.8), F. mandshurica(44.8), Q. serrata(27.5), Acer pseudo-sieboldianum(17.0), C. controversa(l5.9), F. sieboldiana(l1.5), R. schlippenbachii(11.0), C. cordata(11.0), Styrax obassia(10.9), Magnolia sieboldii(10.4) and C. laxiflora(9.8). Distribution of DBH of Q. mongolica had a formality distribution, suggesting a continuous domination of these species over the other species for the time being. In contrast, F. mandshurica appeared limited to the valley of the sheet and a higher frequency of young individuals, suggesting a continuous domination of these species the development of a climax forest terrain. Q. serrata had a higher frequency of young individuals and middle individuals, suggesting a continuous domination of these species over the other species for the time being in contrast. This study examined the correlation between each community and the environment according to DCCA ordination. The Q. mongolica community predominated in the highest elevation habitats which had many C.E.C and T-N. F. mandshurica community predominated in the highest elevation habitats which had many Moisture and EX-Cation. The Q. serrata community and C. laxiflora community mainly occurred in the low elevation habitats which had few C.E.C and T-N. The C. controversa community appeared on the park in the middle habitats.

• Tuberculosis and Respiratory Diseases
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• v.49 no.5
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• pp.576-584
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• 2000

Background : With the increase of cigarette consumption by women and the young, the incidence of lung cancer is expected to increase during the next three or four decades in Korea. The purpose of this study was to analyze the smoking habits in patients with lung cancer and to identify the gender differences in terms of their susceptibility to cigarette related carcinogens. Method : This investigation was a hospital-based case control study, which included the data of 178 case subjects (72 females, 106 males) with lung cancer and 218 control subjects (97 females, 121 males) with diseases unrelated to smoking. The information was obtained through a direct personal interview and a questionnaire related to personal smoking history. Results : The relative frequency of the squamous cell carcinoma was substantially higher in males than in females (61.3% in males, and 29.2% in females), while adenocarcinoma including bronchoalveolar cell carcinoma was higher in females(31.9% in females, 18.9% in males). Kreyberg I lung cancer was of relatively higher frequencies in males and smokers, while Kreyberg II lung cancer was higher in females and never smokers. The odds ratios (ORs) at each exposure level were consistently higher in females than males. For all cell types, the risk of lung cancer was increased with the quantity of smoked cigarettes, duration of smoking, and depth of inhalation. Odds ratio was distinctly higher in Kreyberg I lung cancer than in total lung cancer and a steeper gradient of risk with increased smoking was observed in females. Conclusion : The relative risk for lung cancer was consistently higher in females than in males at every level of exposure to cigarette smoke. This is believed to be due to the higher susceptibility of females to tobacco carcinogens, such as gender associated differences of carcinogen activation and/or the elimination of smoking related metabolites.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.23 no.8
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• pp.2052-2063
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• 1998

Various full-scale radio location systems have been developed since ground-based radio navigation systems appeared during World War II, and more recently global positioning systems (GPS) have been widely used as a representative location system. In addition, radio location systems based on cellular systems are intensively being studied as cellular services become more and more popular. However, these studies have been focused mainly on macrocellular systems of which based stations are mutually synchronized. There has been no study about systems of which based stations are asynchronous. In this paper, we proposed two radio location algorithms in microcellular CDMA systems of which base stations are asychronous. The one is to estimate the position of a personal station at the center of rectangular shaped area which approximates the realistic common area. The other, as a method based on road map, is to first find candidate positions, the centers of roads pseudo-range-distant from the base station which the personal station belongs to and then is to estimate the position by monitoring the pilot signal strengths of neighboring base stations. We compare these two algorithms with three wide-spread algorithms through computer simulations and investigate interference effect on measuring pseudo ranges. The proposed algorithms require no recursive calculations and yield smaller position error than the existing algorithms because of less affection of non-line-of-signt propagation in microcellular environments.

• Korean Journal of Environment and Ecology
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• v.24 no.6
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• pp.708-722
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• 2010

This study was carried out to classify vegetation structure of the Hyangjeokbong in the Deogyusan National Park using the gradient analysis and phytosociological method. The vegetation was classified into Quercus mongolica community(Rhododendron schlippenbachii subcommunity, typical subcommunity), Q. serrata community, Q. variabillis community, Pinus densiflora community, Cornus controversa community, Fraxinus mandshurica community and Taxus cuspidata community. Ecological characteristics such as species composition, layer structure, vegetation ratio, and the distribution of individual trees by DBH(diameter at breast height) were significantly different among communities. The order of important value of the forest community with DBH 2cm above plants was Q. mongolica(81.2), F. mandshurica, Q. serrata, P. densiflora, Acer pseudosieboldianum, Q. variabillis, Rhododendron schlippenbachii, C. controversa, T. cuspidata. Distribution of DBH of Q. mongolica and Q. serrata had suggesting a continuous domination of these species over the other species for the time being. In contrast, F. mandshurica appeared limited to the valley of the sheet and a higher frequency of young individuals, suggesting a continuous domination of these species the development of a climax forest terrain. P. densiflora and T. cuspidata had suggesting a continuous domination of these species over the other species for the time being in maintain. Q. variabilis and C. controversa had a formality distribution, suggesting a continuous domination of these species over the other species for the time being. This study examined the correlation between each community and the environment according to DCCA ordination. The Q. mongolica community and T. cuspidata community predominated in the highest elevation habitats which had few moisture, Ca and in the low pH. The Q. serrata community mainly occurred in the low elevation habitats which had many moisture. P. densiflora community predominated in the middle elevation and south-facing slope habitats which had few moisture, Ca and in the low pH. F. mandshurica community predominated in the low elevation habitats which had many moisture, Ca and pH.

• Journal of Chest Surgery
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• v.34 no.10
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• pp.754-762
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• 2001

Background: To evaluate the efficacy of arterial switch operation for transposition of great arteries, serial echocardiographic studies were performed in 8 patients who underwent the surgery between 1989 and 1998 at Dept. of Thoracic & Cardiovascular Surgery, Yeungnam University Hospital in Daegu City, Korea. Material and Method: Follow-up period ranged from 6 months to 11 years(average of 4.1 years). Body weight ranged from 2.6kg to 4.8kg, with average of 3.6kg. 5 of 8 patients were preoperatively diagnosed as TGA+VSD, and 3 as TGA+IVS. LV function was evaluated by the measurement of LV shortening fraction, LVSTI, and LVEF. RVSTI was also measured. Postoperative function of valve and growth of great vessels were analyzed by the measurement of PSPGV, valvular regurgitation, LA/AO ratio, root dimension of aorta and pulmonary artery, comparing with the age matched controls, respectively. Result: LVEF had an average of 65.0+9.03% which is tended to increase serially. LVAOPG had an average of 15.9mmHg. RVPAPG, 27.5mmHg. From the measurement of aortic root dimension of 6 patients at end-systole, aortic root growth was assumed to increase more than the mean value of normal growth. PA root dimension at end-systole showed a similar growth progress when compared with age matched normal controls. Postoperative pulmonic valve regurgitation was noted in 5 of total 8 patients, in which 1 patient who showed grade 2 and 4 showed below grade 1. AR, in 6 patients and all grade 1 Except 1 patient, all the valvular regurgitations were below grade 1, which was presumed to be clinically insignificant.

• Journal of Chest Surgery
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• v.42 no.6
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• pp.696-703
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• 2009

Background: A Comprehensive Aortic Root and Valve Reconstruction (CARVAR) procedure is comprised of aortic root wall reconstruction and corrections of the leaflets for treating various aortic valve diseases. We evaluated our recent early clinical experience with the CARVAR procedure. Material and Method: From October 2007 to September 2008, 114 cases (66 males) of CARVAR procedures were performed, The mean patient age was 53 years (range: 14~84) The patients were divided into 4 groups: 1) the AAR group: aortic regurgitation with aortic root wall deformity such as annulo-aortic ectasia or ascending aortic aneurysm (n=18), 2) the IAR group: isolated AR with leaflet abnormality (n=42), 3) the IAS group: isolated aortic stenosis (n=51) and 4) the PAVR group: previous aortic valve replacement (n=3). Sinotubular junction (STJ) reduction was done in all the patients, leaflet correction was done in 10 of the AAR group patients and in all the patients of the other groups, annulus reduction was done in 14 of the MR group patients and in 6 of the IAR group patients. Aortic dissection was excluded from this analysis. Result: There was no mortality or follow-up death. The diameter of the aortic sinus decreased from $54.6{\pm}8.4$ mm to $38.3{\pm}3.8$ mm in the AAR group, the mean AR grade decreased from 3.2 to 0.2 in the IAR group, the mean aortic valve pressure gradient decreased from $47.1{\pm}24.4$ mmHg to $15.1{\pm}11.7$ mmHg in the IAS group and the mean AR grade decreased to 0 in the PAVR group. Balloon type coronary perfusion cannula-related coronary ostial stenosis developed in 4 patients and this was treated with OPCAB in three patients and with PTCA in one patient. Two patients developed postoperative infectious endocarditis. All the patients were discharged and followed up in a stable condition. Conclusion: The CARVAR procedure showed excellent short term results, but a good further follow up result is required to apply this procedure to most kinds of aortic valve diseases.

• Korean Journal of Soil Science and Fertilizer
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• v.39 no.5
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• pp.259-267
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• 2006

Hydraulic conductivity is the rate of water flux on hydraulic gradient. The van Genuchten Mualem (VGM) model is frequently used for describing unsaturated state of soils, that is composed with the function of soil water potential and soil water content and requests various parameters. This study is to get the value of VGM parameters used Rosetta computer program based on neural network analysis method and to calculate VGM parameters. VGM parameters included Ko(effective saturated hydraulic conductivity), ${\theta}r$(residual soil water content), ${\theta}s$(saturated soil water content), L, n and m. The unsaturated hydraulic conductivity at 10 kPa was calculated by using Rosetta program. Unsaturated hydraulic conductivities of 17 soil series at 1, 3, 5, 7 kPa were also obtained by applying saturated hydraulic conductivity by disk tension infiltrometer based on Gardner and Wooding's equation. Water flow at the water potential of 3 kPa was very low except Namgye, Hagog, Baegsan, Sangju, Seogcheon, Yesan soil series. Unsaturated hydraulic conductivity at 1 kPa showed the highest value for Samgag soil series and was in order of Yesan, Hwabong, Hagog and Baegsan soil series. Those of Gacheon, Seocheon and Ugog soil series were very low. When the value by VGM was compared with the value by disc tension infiltrometer, there was a tendency with exponential function to soils without gravel but there was no tendency to soils including gravel. Conclusively, it would be limited that VGM model for unsaturated hydraulic conductivity analysis applies to Korean agricultural land including gravel and having steep slope, shallow soil depth.