• Journal of Korean Society of Forest Science
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• v.45 no.1
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• pp.11-25
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• 1979

There was much mass movement at many different mountain side of Peong Chang area in Kwangwon province by the influence of heavy rainfall through August/4 5, 1979. This study have done with the fact observed through the field survey and the information of the former researchers. The results are as follows; 1. Heavy rainfall area with more than 200mm per day and more than 60mm per hour as maximum rainfall during past 6 years, are distributed in the western side of the connecting line through Hoeng Seong, Weonju, Yeongdong, Muju, Namweon and Suncheon, and of the southern sea side of KeongsangNam-do. The heavy rain fan reason in the above area seems to be influenced by the mouktam range and moving direction of depression. 2. Peak point of heavy rainfall distribution always happen during the night time and seems to cause directly mass movement and serious damage. 3. Soil mass movement in Peongchang break out from the course sandy loam soil of granite group and the clay soil of lime stone and shale. Earth have moved along the surface of both bedrock or also the hardpan in case of the lime stone area. 4. Infiltration seems to be rapid on the both bedrock soil, the former is by the soil texture and the latter is by the crumb structure, high humus content and dense root system in surface soil. 5. Topographic pattern of mass movement spot is mostly the concave slope at the valley head or at the upper part of middle slope which run-off can easily come together from the surrounding slope. Soil profile of mass movement spot has wet soil in the lime stone area and loose or deep soil in the granite area. 6. Dominant slope degree of the soil mass movement site has steep slope, mostly, more than 25 degree and slope position that start mass movement is mostly in the range of the middle slope line to ridge line. 7. Vegetation status of soil mass movement area are mostly fire field agriculture area, it's abandoned grass land, young plantation made on the fire field poor forest of the erosion control site and non forest land composed mainly grass and shrubs. Very rare earth sliding can be found in the big tree stands but mostly from the thin soil site on the un-weatherd bed rock. 8. Dangerous condition of soil mass movement and land sliding seems to be estimated by the several environmental factors, namely, vegetation cover, slope degree, slope shape and position, bed rock and soil profile characteristics etc. 9. House break down are mostly happen on the following site, namely, colluvial cone and fan, talus, foot area of concave slope and small terrace or colluvial soil between valley and at the small river side Dangerous house from mass movement could be interpreted by the aerial photo with reference of the surrounding site condition of house and village in the mountain area 10. As a counter plan for the prevention of mass movement damage the technics of it's risk diagnosis and the field survey should be done, and the mass movement control of prevention should be started with the goverment support as soon as possible. The precautionary measures of house and village protection from mass movement damage should be made and executed and considered the protecting forest making around the house and village. 11. Dangerous or safety of house and village from mass movement and flood damage will be indentified and informed to the village people of mountain area through the forest extension work. 12. Clear cutting activity on the steep granite site, fire field making on the steep slope, house or village construction on the dangerous site and fuel collection in the eroded forest or the steep forest land should be surely prohibited When making the management plan the mass movement, soil erosion and flood problem will be concidered and also included the prevention method of disaster.

• Korean Journal of Soil Science and Fertilizer
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• v.10 no.3
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• pp.189-201
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• 1977

Some of basic aspects of soil potassium with special reference to soil physical properties were discussed. Data in the Official Soil Series Description(Korea) was analyzed according to soil type, land form, and soil texture to find soil potassium status which may explain different response to potassium application. Exchangeable potassium contents decreased with soil depth irrespective of soil type, land form and soil texture. Change in degree of potassium saturation within soil profile was not so clear as exchangeable potassium but the degree of potassium saturation of A horizon was highest among soil horizon. Soils of terrace and mountain foot slope showed high values both in exchangeable potassium and degree of potassium sauration and only these two soils were classified as soils having exchangeable potassium higher than 0.3 meq per 100g of soil and degree of potassium saturation higher than 5.0%. Exchangeable potassium of fine loamy and fine clayey soils is higher than 0.3 meq per 100g of soil but degree of potassium saturation is lower than 4.0%. Degree of potassium saturation of sandy soils exceeds 5.0% but exchangeable potassium is very low. Soils of rolling, hilly, unmatured and alpine land soils have lower exchangeable potassium and show lower degree of potassium saturation. The highest distribution of exchangeable potassium content irrespective of soil horizons was shown in the range of 0.1-0.2 meq per 100g of soil. The highest distribution of degree of potassium saturation was in the range of 2.0-3.0% in A horizon and 1.0-2.0% in B and C horizons. Of the soil series concerned in this analysis, 27.3% in A horizon, 11.1% in B horizon and 4.0% in C horizon had exchangeable potassium higher than 0.3 meq per 100g of soil and 18.0% in A horizon, 6.3% in B horizon, and 4.1% in C horizon showed degree of potassium saturation higher than 5.0%. The low response of potassium application only to soils in terrace and mountain foot slope may be resulted from the high exchangeable potassium content and high degree of potassium saturation. It is concluded that a great response of potassium application to soils is expected especially in dry season.

• Radiation Oncology Journal
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• v.25 no.4
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• pp.268-277
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• 2007

Purpose: Respiratory motion is a considerable inhibiting factor for precise treatment with stereotactic radiosurgery using the CyberKnife (CK). In this study, we developed a moving phantom to simulate three-dimensional breathing movement and investigated the distortion of dose profiles between the use of a moving phantom and a static phantom. Materials and Methods: The phantom consisted of four pieces of polyethylene; two sheets of Gafchromic film were inserted for dosimetry. Treatment was planned to deliver 30 Gy to virtual tumors of 20, 30, 40, and 50 mm diameters using 104 beams and a single center mode. A specially designed robot produced three-dimensional motion in the right-left, anterior-posterior, and craniocaudal directions of 5, 10 and 20 mm, respectively. Using the optical density of the films as a function of dose, the dose profiles of both static and moving phantoms were measured. Results: The prescribed isodose to cover the virtual tumors on the static phantom were 80% for 20 mm, 84% for 30 mm, 83% for 40 mm and 80% for 50 mm tumors. However, to compensate for the respiratory motion, the minimum isodose levels to cover the moving target were 70% for the $30{\sim}50$ mm diameter tumors and 60% for a 20 mm tumor. For the 20 mm tumor, the gaps between the isodose curves for the static and moving phantoms were 3.2, 3.3, 3.5 and 1.1 mm for the cranial, caudal, right, and left direction, respectively. In the case of the 30 mm tumor, the gaps were 3.9, 4.2, 2.8, 0 mm, respectively. In the case of the 40 mm tumor, the gaps were 4.0, 4.8, 1.1, and 0 mm, respectively. In the case of the 50 mm diameter tumor, the gaps were 3.9, 3.9, 0 and 0 mm, respectively. Conclusion: For a tumor of a 20 mm diameter, the 80% isodose curve can be planned to cover the tumor; a 60% isodose curve will have to be chosen due to the tumor motion. The gap between these 80% and 60% curves is 5 mm. In tumors with diameters of 30, 40 and 50 mm, the whole tumor will be covered if an isodose curve of about 70% is selected, equivalent of placing a respiratory margin of below 5 mm. It was confirmed that during CK treatment for a moving tumor, the range of distortion produced by motion was less than the range of motion itself.

• Korean Journal of Ecology and Environment
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• v.36 no.4 s.105
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• pp.455-462
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• 2003

This study evaluated the change of water quality and chlorophyll - a at the birth stage of a large reclaimed estuarine lake (Lake Hwaong) of which the dike was finally constructed in March, 2002. Physico -chemical parameters and chlorophyll - a were investigated along a longitudinal transect, including 3 in-lake sites and 1 out-lake site from June to November, 2002. Salinity at all in-lake sites was over 21 psu during the study period, indicating that lake is still in the seawater phase. Salinity was periodically diluted at times when precipitation was high, especially in August. Chemocline was established in July near the dam site, and correspondingly vertical profile of dissolved oxygen was very clear during that Period. Total nitrogen and phosphorus concentrations at all lake sites were in the eutrophic range, and they were especially high at the stream inlet site. Nutrients concentration was not much varied vertically but significantly varied temporally, and correlated significantly with precipitation and chlorophyll-a concentration, indicating that inflowing water from the watershed seemed not to improve lake water by dilution but cause eutrophication of the lake, and thereby stimulate phytoplankton development. Based on the analyses of nutrient ratio (N/P) and trophic state deviation, both phosphorus and nitrogen appeared to limit phytoplankton growth in the lake. Phosphorus limitation appeared to be probable at all in-lake sites with being most severe at the stream inlet site. Nitrogen limitation seemed to occur at both in-lake and out-lake sites. These results indicate that in Lake Hwaong experiencing the very early stage of a reclaiming lake, water quality and phytoplankton development appear to be affect-ed largely by salinity and hydrology and nutrients from the inflowing water. Lake biogeochemistry is still very unstable, and thus further long-term study is necessary to understand the effects of seawater to freshwater conversion on lake biology and water chemistry.

• Journal of the Korean Society of Food Science and Nutrition
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• v.40 no.12
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• pp.1781-1786
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• 2011

This study was conducted to investigate the cause of microbiological contamination in yogurt and evaluate the effect of physicochemical treatment on the growth inhibition of Hanseniaspora uvarum isolated from yogurt. The yeast strain Hanseniaspora uvarum Y1 was subjected to heat and pH treatments. H. uvarum Y1 was killed at $70^{\circ}C$ and $80^{\circ}C$ after 15 min and survived in a wide pH range from pH 2 to 9. However, it did not survive under pH 1 and over pH 10. In a disk diffusion susceptibility test on H. uvarum Y1, a clear zone (5 mm) of growth inhibition was observed upon treatment with electrolyzed water. The effect of ozone gas on the growth of H. uvarum Y1 was evaluated by viable cell count. Initial cell numbers of $10^2$ and $10^3$ CFU/mL of H. uvarum Y1 were completely killed by treatment for 10 and 30 min, respectively. H. uvarum Y1 was also sterilized by microwave treatment for 1 min. When treated with gamma-irradiation, the rate of killing of H. uvarum Y1 was proportional to the irradiation dose. and complete killing occurred at a dose of 50 kGy.

• Journal of Intelligence and Information Systems
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• v.21 no.4
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• pp.1-16
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• 2015

Traffic accident is one of the major cause of death worldwide for the last several decades. According to the statistics of world health organization, approximately 1.24 million deaths occurred on the world's roads in 2010. In order to reduce future traffic accident, multipronged approaches have been adopted including traffic regulations, injury-reducing technologies, driving training program and so on. Records on traffic accidents are generated and maintained for this purpose. To make these records meaningful and effective, it is necessary to analyze relationship between traffic accident and related factors including vehicle design, road design, weather, driver behavior etc. Insight derived from these analysis can be used for accident prevention approaches. Traffic accident data mining is an activity to find useful knowledges about such relationship that is not well-known and user may interested in it. Many studies about mining accident data have been reported over the past two decades. Most of studies mainly focused on predict risk of accident using accident related factors. Supervised learning methods like decision tree, logistic regression, k-nearest neighbor, neural network are used for these prediction. However, derived prediction model from these algorithms are too complex to understand for human itself because the main purpose of these algorithms are prediction, not explanation of the data. Some of studies use unsupervised clustering algorithm to dividing the data into several groups, but derived group itself is still not easy to understand for human, so it is necessary to do some additional analytic works. Rule based learning methods are adequate when we want to derive comprehensive form of knowledge about the target domain. It derives a set of if-then rules that represent relationship between the target feature with other features. Rules are fairly easy for human to understand its meaning therefore it can help provide insight and comprehensible results for human. Association rule learning methods and subgroup discovery methods are representing rule based learning methods for descriptive task. These two algorithms have been used in a wide range of area from transaction analysis, accident data analysis, detection of statistically significant patient risk groups, discovering key person in social communities and so on. We use both the association rule learning method and the subgroup discovery method to discover useful patterns from a traffic accident dataset consisting of many features including profile of driver, location of accident, types of accident, information of vehicle, violation of regulation and so on. The association rule learning method, which is one of the unsupervised learning methods, searches for frequent item sets from the data and translates them into rules. In contrast, the subgroup discovery method is a kind of supervised learning method that discovers rules of user specified concepts satisfying certain degree of generality and unusualness. Depending on what aspect of the data we are focusing our attention to, we may combine different multiple relevant features of interest to make a synthetic target feature, and give it to the rule learning algorithms. After a set of rules is derived, some postprocessing steps are taken to make the ruleset more compact and easier to understand by removing some uninteresting or redundant rules. We conducted a set of experiments of mining our traffic accident data in both unsupervised mode and supervised mode for comparison of these rule based learning algorithms. Experiments with the traffic accident data reveals that the association rule learning, in its pure unsupervised mode, can discover some hidden relationship among the features. Under supervised learning setting with combinatorial target feature, however, the subgroup discovery method finds good rules much more easily than the association rule learning method that requires a lot of efforts to tune the parameters.

• Journal of Biosystems Engineering
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• v.3 no.1
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• pp.47-63
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• 1978

This study was conducted to obtain a basic information necessary to assess present rice milling technology in Korea The profiles for milling plants was analyzed by survey work.For the private custom-work mills, which process about 80 percent of domestic rice consumption ,their actual milling test for the identical samples as used for filed mills was conducted. Two rice varieties Japonica and Tongil-type were associated with the experiments. The results are summarized as follows: 1. Analyses for private custom-work mills showed their general aspects as; about 91 percent of the mills belonged to an individual owner ship ; more than 93 percent of the mills was established earlier than 1950 ; about 80 percent of the mills was powered with electric motor; mills having less than two employees were about 75 percent; about 45 percent of the mills provided for warehouse in storing customers cereal grains. 2. The polishers installed in 1,255mills within the surveyed area (7 counties) have been supplied by 44 different domestic manufacturers ;in but about 60 percent of which was supplied by 6major manufacturers. The polishers could be classified into two categories in terms of principles of their polishing actions ;jet-pearler and friction types. About 51 percent of the mills was equipped with the former which has been recognized as giving greater milling recovery than the friction types. 3. Reason for owners of private mills to supplement new machines was due mainly to pgrading their mills to meet the requirements that established by the Government. However, about 60 percent of the mill owners intended to replace with new pearler by their own needs to meet with new high yielding varieties. 4. Processing systems of each previate rice mills surveyed could be classified into three categories, depending upon whether the systems posessed such components as precleaner and paddy separator or not. Only 36.7 percent of mills was installed with both precleanr ad paddy seperrator, 5.0 percent of mills did have neither percleaner nor paddy seperator, and rest of them equipped only one of the two. Hence,it is needed for about 63% of rice miils to be supplemented with these basic facilities to meet with the requirements for the standaized system. 5. Actual milling capacity measured at each field rice mills was shown a wide variation, having range from about 190 to 1,210 kg/hr. The percentages of mills classified according to daily milling capacity based on this hourly capacity were 24.3% for the capacity less than 3 M/T a day; 20.0% for 3-4 M/T; 15.6% for 4-5 M/T; 6.7% for 5-6 M/T; 22.3% for 6-7 M/T; and 11.0% for more than 7 M/T a day. 6. Actual amount of rice processed was about 310 M/T a year in average. About 42% of total milled rice was processed during October to Decembear, which formed a peak demand period for rice mills. The amount of rice milled during January to May was relatively small, but it had still a large amount compared to that during June to September. 7. Utilization rate of milling facility, i. e., percentage of the actual amount of milled rice to the capacity of rice mills, was about 18% on the year round average, about 41% in the peak demand season, and about 10% during June to September. Average number of operating days for mills surveyed was about 250 days a year, and about 21 days a month. 8. Moisture contents of paddy at the time of field mill tests were ranged 14.5% to 19.5% for both Japonica and Tong-i] varieties, majority of paddy grains having moisture level much higher than 1530. To aviod potential reduction of milling recovery while milling and deterioration of milled rice while storage due to these high grain mJisture contents, it may be very important for farmers holding rice to dry by an artificial drying method. 9. Milling recovery of JapJnica varieties in rice mills was 75.0% in average and it was widely ranged from 69.0% to 78.0 % according to mills. Potential increase in milJing recovery of Japonica variety with improvement of mill facilities was estimated to about 1.9%. On the other hand, milling recovery of Tong-il varieties in the field mill tests was 69.8% in average and it ranged from 62% to 77 %, which is much wider than that of Japonica varieties. It is noticed that the average milling recovery of Tong-il variety of 69.8% was much less than that of the Japonica-type. It was estimated th3.t up to about 5.0% of milling recovery for Tong-il variety could be improved by improving the present lo'.ver graded milling technology. 10. Head rice recoveries, as a factor of representing the quality of commercial goods, of Japonica and Tong-il varieties were 65.9% and 53.8% in average, and they were widely ranged from 52% to 73% and from 44% to 65% , respectively. It was assessed that head rice recovery of Japonica varieties can be improved up 3.3% and that of Tong-il varieties by 7.0% by improving mill components and systems.

• Journal of Bio-Environment Control
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• v.20 no.2
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• pp.93-100
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• 2011

Maintenance of adequate soil water potential during the period of crop growth is necessary to support optimum plant growth and yields. A better understanding of soil water movement within and below the rooting zone can facilitate optimal irrigation scheduling aimed at minimizing the adverse effects of water stress on crop growth and development and the leaching of water below the root zone which can have adverse environmental effects. The objective of this study was to evaluate the feasibility of using a portable irrigation controller with an Watermark sensor for the cultivation of drip-irrigated vegetable crops in a greenhouse. The control capability of the irrigation controller for a soil water potential of -20 kPa was evaluated under summer conditions by cultivating 45-day-old tomato plants grown in three differently textured soils (sandy loam, loam, and loamy sands). Water contents through each soil profile were continuously monitored using three Sentek probes, each consisting of three capacitance sensors at 10, 20, and 30 cm depths. Even though a repeatable cycling of soil water potential occurred for the potential treatment, the lower limit of the Watermark (about 0 kPa) obtained in this study presented a limitation of using the Watermark sensor for optimal irrigation of tomato plants where -20 kPa was used as a point for triggering irrigations. This problem might be related to the slow response time and inadequate soil-sensor interface of the Watermark sensor as compared to a porous and ceramic cup-based tensiometer with a sensitive pressure transducer. In addition, the irrigation time of 50 to 60 min at each of the irrigation operation gave a rapid drop of the potential to zero, resulting in over irrigation of tomatoes. There were differences in water content among the three different soil types under the variable rate irrigation, showing a range of water contents of 16 to 24%, 17 to 28%, and 24 to 32% for loamy sand, sandy loam, and loam soils, respectively. The greatest rate increase in water content was observed in the top of 10 cm depth of sandy loam soil within almost 60 min from the start of irrigation.

• Korean Journal of Soil Science and Fertilizer
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• v.2 no.1
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• pp.1-13
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• 1969

A total of 129 surface(upto 30 cm depth) soil samples were selected from the profile samples collected during reconnaissance soil survey in 1967, for the determination of phosphorus absorption co-efficient. The distribution range for each soil association has been established. The physicochemical factors affecting the phosphorus absorption coefficient have also been examined. The following general conclusions can be drown: 1. In general, the phosphorus absorption coefficient of the soil association of presently arable land are lower than the soils which are not in cultivation. 2. The higher the cation exchange capacity of soils, the higher is the phosphorus absorption coefficient. The factors governing phosphorus absorption coefficient in various soil associations are as follows: Parent Material Soil Association Governing Factor Fluvio marine Low Humic Gley Fluvio marine Alluvial Complex Narrow valley Siliceo mafic materials Red-yellow podzolic Redish Siliceo mafic materials Brown Lateritic Clay content Siliceous crystalline materials Lithosols C.E.C. & Clay content Alluvium Low Humic Alluvium Gley Alluvial Organic matter Siliceous crystalline materials Red-Yellow Podzolic Organic matter and clay content 4. The relation between phosphorus absorption coefficient determined by $(NH_4)_2HPO_4(y)$ and by the P 700 ppm $NaH_2PO_4(x)$ is $Y=2.716X+37(r=0.96^{**})$ which shows highly significant positive correlation and linear regression.

• Journal of Chest Surgery
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• v.30 no.7
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• pp.663-669
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• 1997

This is a report on the clinical outcome and hemodynamic profile of the ATSwcardiac valve prosthesis, which is a recently introduced pyrolytic carbon bileaflet prosthesis. We retrospectively reviewed the early outcome of 100 consecutive patients who underwent isolated cardiac valve replacement with the ATS(w prosthesis from October 1994 through June 1996 at our hospital. All patients were evaluated with Doppler echocardiography before discharge from the hospital. The mean age of the patients was 48.6 years(range: 2 to 74). A tota of 124 prosthesis were implanted; 71 mitral, 46 aortic, and 7 tricuspid. The two most frequently used sizes were 27 mm(40.8%) and 29 mm(35.2%) in the mitral position, and 23 mm(30.4%) and 21 mm(28.3%) in the aortic position. There was no early or late death. The total follow-up period was 950 patient-months with 99% follow-up rate. Serious late morbidity occurred in three patients; reoperation in two patients for late rupture of Sinus of Valsava in one and for endocarditis with prosthetic dehiscence in the other, and intracranial hemorrhage due to hypertension in one patient. There has been no thromboembolic complication or structural valval deterioration. In the mitral position, the average values of peak and mean transprosthetic pressure gradients and valve area calculated from pressure half time were 6.9$\pm$2.8 mmHg, 2.6$\pm$ 1.5 mmHg, and 2.7 $\pm$0.8 cm2 respectively. In the aortic position, the peak and mean pressure gradients'were 26.4 $\pm$ 15.9 mmHg and 14.2 $\pm$ 7.9 mmHg. For the mitra prostheses larger than 25-mm size, there was no significant difference among prosthetic sizes in terms of transprosthetic gradients, whereas there was a significant negative correlation between the prosthesis size and the transprosthetic gradients for the aortic valves. The peak and mean Pressere pradients were 52.2 $\pm$ 17.6 tmHg and 26.9$\pm$ 7.4 mmHg across the 19-mm aortic Prostheses, and 27.1 $\pm$ 11.9 mmHg and 13.3$\pm$6.6 mmHg across the 21-mm size. Above results can lead to the conclusion that the early clinical outcome of the ATS valve prosthesis is quite satisfactory, And the hemodynamic characteristics are comparable, if not better, with other bileaflet prostheses.