• The Korean Journal of Quaternary Research
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• v.21 no.1
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• pp.27-36
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• 2007

The severe damage of cultural heritages induced by natural hazards like heavy rain has been dramatically increased since 1990. The number of the repair works of stone heritage of 2005 was six times as many as those of 1986 year. Especially the ratio of the repair works of Gyeongsang Province and Jeolla Province stood 63% of those of all over the country. Since 1990, the typhoons usually struck the southern part of Korea and went northward. The heavy damage of stone heritages in two provinces was caused by them. We made a preliminary survey the stone heritages that exposed to the natural hazards on the basis of repair works of them and a field survey. The analysis results indicate that the natural hazards such as landslide and soil disaster of the stone heritages related to a sloping surface stood 58% of all kind of natural hazards. The reasons are caused by the 59 % of all the stone heritages distributed in a sloping surface resulted in natural hazards like landslide and soil disaster. The bases of stone heritages can be easily eroded by the surface water with high energy induced by heavy rainfall. Most of the stone heritages like Maebul were engraved on a natural rock wall(outcrop). But some of them engraved on rolling stones are very vulnerable in a change of a base condition caused by erosion and ground subsidence and they can be tilted or fell down. The distribution of the stone heritages vulnerable in natural hazard is related to that of the rainfall distribution compounded five typhoons after 1990. Most of them are included in level two on the rainfall distribution map except those of Taean peninsula and some of Gyeonggi Province. They seem to be rather related to the rainfall distribution of the Typhoon Olga.

• The Journal of Korean Society for Radiation Therapy
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• v.24 no.1
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• pp.39-43
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• 2012

Purpose: In hospital image-guided radiation therapy in patients with bladder cancer to enhance the reproducibility of the appropriate amount, depending on the patient's condition, and image-guided injection of saline system (On-Board Imager system, OBI, VARIAN, USA) three of the Cone-Beam CT dimensional matching (3D-3D matching) to be the treatment. In this study, the treatment of patients with bladder cancer at Cone-Beam CT image obtained through the analysis of the bones based matching and matching based on the bladder to learn about the differences, the bladder's volume change injected saline solution by looking at the bladder for the treatment of patients with a more appropriate image matching is to assess how the discussion. Materials and Methods: At our hospital from January 2009 to April 2010 admitted for radiation therapy patients, 7 patients with bladder cancer using a Folly catheter of residual urine in the bladder after removing the amount determined according to individual patient enough to inject saline CT-Sim was designed after the treatment plan. After that, using OBI before treatment to confirm position with Cone-Beam CT scan was physician in charge of matching was performed in all patients. CBCT images using a total of 45 bones, bladder, based on image matching and image matching based on the difference were analyzed. In addition, changes in bladder volume of Eclipse (version 8.0, VARIAN, USA) persuaded through. Results: Bones, one based image matching based on the bladder and re-matching the X axis is the difference between the average $3{\pm}2mm$, Y axis, $1.8{\pm}1.3mm$, Z-axis travel distance is $2.3{\pm}1.7mm$ and the overall $4.8{\pm}2.0mm$, respectively. The volume of the bladder compared to the baseline showed a difference of $4.03{\pm}3.97%$. Conclusion: Anatomical location and nature of the bladder due to internal movement of the bones, even after matching with the image of the bladder occurred in different locations. In addition, the volume of saline-filled bladder showed up the difference between the 4.03 percent, but matched in both images to be included in the planned volumes were able to confirm. Thus, after injection of saline into the bladder base by providing a more accurate image matching will be able to conduct therapy.

• Journal of Intelligence and Information Systems
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• v.17 no.4
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• pp.241-254
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• 2011

Financial time-series forecasting is one of the most important issues because it is essential for the risk management of financial institutions. Therefore, researchers have tried to forecast financial time-series using various data mining techniques such as regression, artificial neural networks, decision trees, k-nearest neighbor etc. Recently, support vector machines (SVMs) are popularly applied to this research area because they have advantages that they don't require huge training data and have low possibility of overfitting. However, a user must determine several design factors by heuristics in order to use SVM. For example, the selection of appropriate kernel function and its parameters and proper feature subset selection are major design factors of SVM. Other than these factors, the proper selection of instance subset may also improve the forecasting performance of SVM by eliminating irrelevant and distorting training instances. Nonetheless, there have been few studies that have applied instance selection to SVM, especially in the domain of stock market prediction. Instance selection tries to choose proper instance subsets from original training data. It may be considered as a method of knowledge refinement and it maintains the instance-base. This study proposes the novel instance selection algorithm for SVMs. The proposed technique in this study uses genetic algorithm (GA) to optimize instance selection process with parameter optimization simultaneously. We call the model as ISVM (SVM with Instance selection) in this study. Experiments on stock market data are implemented using ISVM. In this study, the GA searches for optimal or near-optimal values of kernel parameters and relevant instances for SVMs. This study needs two sets of parameters in chromosomes in GA setting : The codes for kernel parameters and for instance selection. For the controlling parameters of the GA search, the population size is set at 50 organisms and the value of the crossover rate is set at 0.7 while the mutation rate is 0.1. As the stopping condition, 50 generations are permitted. The application data used in this study consists of technical indicators and the direction of change in the daily Korea stock price index (KOSPI). The total number of samples is 2218 trading days. We separate the whole data into three subsets as training, test, hold-out data set. The number of data in each subset is 1056, 581, 581 respectively. This study compares ISVM to several comparative models including logistic regression (logit), backpropagation neural networks (ANN), nearest neighbor (1-NN), conventional SVM (SVM) and SVM with the optimized parameters (PSVM). In especial, PSVM uses optimized kernel parameters by the genetic algorithm. The experimental results show that ISVM outperforms 1-NN by 15.32%, ANN by 6.89%, Logit and SVM by 5.34%, and PSVM by 4.82% for the holdout data. For ISVM, only 556 data from 1056 original training data are used to produce the result. In addition, the two-sample test for proportions is used to examine whether ISVM significantly outperforms other comparative models. The results indicate that ISVM outperforms ANN and 1-NN at the 1% statistical significance level. In addition, ISVM performs better than Logit, SVM and PSVM at the 5% statistical significance level.

• Journal of Korean Society of Forest Science
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• v.103 no.4
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• pp.622-629
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• 2014

This study aims to develop a standard diagnostic table for mountain ginseng so that the cultivators not only can check their current level of management with the table, but also can understand and address operational challenges better by themselves utilizing the table. The standard diagnostic table consists of 3 categories and 18 subcategories to diagnose the general status of forestry households, the indicators of management performance and the level of management. To develop the table, the study conducted a survey on the actual condition of management, targeting 81 forestry households throughout 15 municipalities including Mu-ju, Jeollabukdo, and Ham-yang, Gyeongsangnamdo, all of which are the chief producing districts of mountain ginseng. Then, the study calculated total scores by regions by aggregating the scores of 18 subcategories, in order to evaluate and compare the management level among regions based on the scores. According to the result, the average score of 81 forestry households was 57.2 point-58% of which surveyed belonged to the range of 40-60 point. Compared by regions, the average score of Jeollabukdo regions was 52.9 point, the lowest, and that of Gyeongsangnamdo regions was 61.4 point, the highest. It is remarkable that among the indicators of management base, the average score of 'mounding (the height of mound)' item was recorded rather low with 1.59 point, reflecting the fact that the cultivators tend to raise mountain ginseng with no additional mounds. As for the indicators of production skills, the average score of the pest control item was remarkably low with 1.28 point. Over 90% of cultivators answered that they do not usually forecast or survey the pest disease in advance. Meanwhile, it is also noticeable that the item of sowing and planting methods, and the item of seed were both rather high, recording 4.00 and 4.47 point respectively. As for the item of management and sales skill, however, the score was rather low with 2.20 point, meaning that the forestry households still have a low interest in the business management.

• Journal of the Korean Society of Radiology
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• v.8 no.7
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• pp.467-477
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• 2014

The purpose of this study is to offer data base for establishment of dental training x-ray generator based safety usage through surveying real radiation safety management state of radiation worker's in plan of operations that have dental training x-ray generators and use it. For it, comprehensive references were surveyed referring reports of current state of regulation technique development and domestic radiation safety evaluation and nuclear related legislation regarding radiation safety management of dental training x-ray generators. On the basis of it, questionnaires were filled in about respondent's general characteristic radiation safety manager's status current state of radiation safety management and the level of knowledge & consciousness. For the study, the survey was conducted to 224 people of radiation safety managers and university graduates training assistants and full-time professors who can treat dental training x-ray generators in education center. through this survey 95 questionnaires were used as analysis materials except the insufficient and omitted responses. As a method of analysis, the frequency and percentage were figured out with the general characteristics and safety manager's status. Chi-square test for frequency and correlation per question analysis and Pearson correlation analysis for crosslevel correlation were done with current state of radiation safety management and knowledge & consciousness level. As a result, running dental training x-ray generators was dealt with by 20's to 40's who have high education level over post undergraduate degree and major in dental hygienic. In addition, female have higher consciousness level for radiation safety management than male. It shows significal linear relation statistically(${\chi}^2$ >5, 0.1${\chi}^2$ >5, 0.3${\chi}^2$ >5, 0.3

• Korean Chemical Engineering Research
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• v.54 no.4
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• pp.533-542
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• 2016

We investigate fluidization characteristics of the mixture of rice husk, silica sand and rice husk ash as a preliminary study for valuable utilization of rice husk ash obtained from gasification of rice husk in a fluidized bed reactor. As experiment valuables, the blending ratio of rice husk and sand (rice husk: sand) is selected as 5:95, 10:90, 20:80 and 30:70 on a volume base. Rice husk ash was added with 6 vol% of rice husk for each experiment and air velocity to the reactor was 0~0.63 m/s. In both rice husk/sand and rice husk/sand/ash mixture, the minimum fluidization velocity (Umf) is observed as 0.19~0.21 m/s at feeding of 0~10 vol.% of rice husk and 0.30 m/s at feeding of 20 vol.% of rice husk. With increasing the amount of rice husk up to 30 vol.%, $U_{mf}$ can not measure due to segregation behavior. The mixing index for each experiment is determined using mixing index equation proposed by Brereton and Grace. The mixing index of the mixture of rice husk/sand and rice husk/sand/ash was 0.8~1 and 0.88~1, respectively. The optimum fluidization condition was found for the good mixing and separation of rice husk ash.

• Journal of Conservation Science
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• v.29 no.3
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• pp.287-296
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• 2013

Excavated iron objects are preserved in stable condition through processes of conservation treatment because they are found in the form of various corrosion products. However, the conservation treatment leads to re-corrosion over time and accordingly, iron objects can be severely damaged, and therefore fundamental measures need to be prepared to control it. In this study, the types and characteristics of corrosion products were scientifically analyzed according to the re-corrosion of iron artifacts. In addition, the stability of the corrosion products was evaluated by exposing the standard samples under the re-corrosion environment. Re-corrosion proceeded with weeping in reddish brown on the cracks of iron artifacts. Weeping was detected akagan$\acute{e}$ite had a low hydrogen ion concentration and high chloride ion. The selection of standard sample goethite, lepidocrocite, hematite, and magnetite, were evaluated corrosive by weeping. After the samples were immersed in HCl(pH 1), $H_2SO_4$(pH 1), $H_2O$(pH 6) solution, they had been maintained for 180 days in relative humidity of 20%, 50%, 80% to investiage the changes of chemical components. As a result of analysis, the changes of chemical components were not showed in goethite, lepidocrocite, and hematite. But magnetite was changed to lepidocrocite in solution including chloride ion($Cl^-$) and to goethite and lepidocrocite solution including sulfuric acid($SO{_4}^{2-}$). Results of the study, in the case of magnetite known as s stable corrosion compound, it was identified the corrosion of magnetite occurs by corrosive ions, which means weeping generated in the iron artifacts can corrode magnetite as well as base metal.

• The Korean Journal of Pesticide Science
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• v.16 no.4
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• pp.294-301
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• 2012

In order to use in the classification of minor crop for the mutual application of safe use guideline, it was compared a green onion with a scallion on the residue property of insecticide bifenthrin and chlorfenapyr. After pesticides were applied 2 times with 1 week interval in that day of harvest, 3 days, 7 days, 10 days and 14 days before harvest, vegetables were harvested, and the residue of pesticides was investigated. Base on the residue in that day of harvest, the deposit of spray solution in vegetables was calculated. The deposit of spray solution of bifenthrin was 123.0 mL/kg in a green onion, and 74 mL/kg in a scallion. In case of chlorfenapyr, it was calculated 126.5 mL/kg in a green onion, and 70.0 mL/kg in a scallion. When the amount of the deposit of both pesticides was compared a green onion with a scallion, it was higher in a green onion. On the other hand, it was estimated the predicted dissipation curve of pesticides in a green onion and a scallion during cultivation. The dissipation curve of bifenthrin was y = 1.0334 $e^{-0.0602x}$ ($R^2$= 0.8606) in a green onion, and y = 0.7693 $e^{-0.1823x}$ ($R^2$= 0.9756) in a scallion. In case of chlorfenapyr, it was y = 2.2603 $e^{-0.0519x}$ ($R^2$= 0.9043) in a green onion, and y = 1.2940 $e^{-0.1051x}$ ($R^2$ = 0.9782) in a scallion. The half-life of bifenthrin was 11.51 days in a green onion, and 3.80 days in a scallion, respectively. Also, it was estimated half-life in chlorfenapyr, it was 13.35 days in a green onion, and 6.59 days in a scallion, respectively. The half-life of both pesticides in a green onion was longer than in a scallion. When both vegetables were compared with the residue property, the deposit of spray solution and half-life of dissipation in a green onion were more than those in a scallion.

• International Journal of Highway Engineering
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• v.11 no.3
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• pp.97-109
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• 2009

One of the main causes of asphalt rutting is high temperature of the pavement. Nevertheless, there has been few research on lowering the pavement temperature for reducing rutting. This study investigated the performance characteristics of moisture-retaining porous asphalt pavement, which is known to have a temperature reducing effect. The purpose of this study is to quantify the temperature reducing effect of moisture-retaining porous asphalt pavement and its effect of reducing rutting through Accelerated Pavement Testing(APT). Additionally, the possibility of reducing the thickness of the pavement in comparison to general dense grade pavement by analyzing structural layer coefficient of moisture retaining pavement. A total of three test sections consisting of two moisture-retaining porous asphalt pavement sections and one general dense-grade porous asphalt pavement section were constructed for this study. Heating and spraying of water were carried out in a regular cycle. The loading condition was 8.2 ton of wheel load, the tire pressure of $7.03kgf/cm^2$, and the contact area of $610cm^2$. The result of this experiment revealed that the temperature reducing effect of the pavement was about $6.6{\sim}7.9^{\circ}C$(average of $7.4^{\circ}C$) for the middle layer and $7.9{\sim}9.8^{\circ}C$(average of $8.8^{\circ}C$) for surface course, resulting in a rutting reduction of 26% at the pavement surface. Additionally, the structural layer coefficient of moisture retaining pavement measured from a laboratory test was 0.173, about 1.2 times that of general dense grade pavement. The general dense-grade porous asphalt pavement test section exhibited rutting at all layers of surface course, middle layer, and base layer, while the test sections of moisture-retaining porous asphalt pavement manifested rutting mostly at surface course only.

• Korean Security Journal
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• no.2
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• pp.259-289
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• 1999

The Security Industry has dynamic working conditions. So this study intends to find the advisable direction for the reduction of accidents. To achieve the aim, the investigation of documents and the examinations of actual proofs have been done to figure the theoretical background and to see the basic knowledge of security industry. The questionnaire was composed of two question sheets to search real data and actual proofs, with making targets of pure security organization and personnel. The one consists of 9 questions to find the scale and extent of security organizations and the population and character of security personnel, and the other 25 questions in 3 major areas to analyze the causes, the frequency rates, the factors, and the condition of accidents. The period of survey was July 15th to October 15th in 1997 by mail/telephone/interview. The questionnaires were efficiently returned from 102 different organizations including the public security groups of Seoul Metropolitan Police Bureau and so on, with the information of 8,222 persons having worked for Korean Security Industry in 1996. So being based on the reality, some meaningful facts were found, and were compared with the national statistics of the Government. This study is made up of 5 chapters : in the 1st chapter the motivation, the object, the method, the direction and the limitation of the approach were presented ,in the 2nd chapter the theoretical background were inferred ; in the 3rd chapter the collected data of accidents in Korean Security Industry were analyzed and explained on the base of the questionnaires , in the 4th chapter the advisable facts connected with preventing accidents were mentioned ; in the last the conclusion were stated. With the replies of 102 different organizations including the information of 8,222 persons in 1996, the main facts found or analyzed through this study are as follows. Firstly, accident is an unpredictable and occasional event. It occurs to man and/or thing, but the frequency rate of accidents in Korean Government and other Institutes has been calculated and evaluated only in the point of the accident related with man. Secondly, the factors of accidents are firstly relevant to the way preventing accidents in Security Industry in Korea. However the frequency rate is academically calculated and evaluated by at once man(population) and hour(time). But the Government has done the rate only by man(population). This can be improper and inaccurate rates. Thirdly, the confused concept of security is used in Korean Government, academic society, corporation and so on. Therefore the detailed formation of the concept is needed for the development of Security Industry in Korea. Fourthly, security organizations can be classified into 'public security(public law enforcement)' and 'private security' according to its identification, and furthermore 'private security' can be divided into 'facilities-guard service', 'body-guard service', and 'patrol service' according to its major role. Fifthly, in the viewpoint of the number of both organization and population,'facilities-guard service' is centered in Korean 'private security'. According to the analyzed results of the questionnaires in this study, the frequency rate of accidents of Korean Security Industry is 0.43(%) totally in 1996 : 'facilities-guard service' 0.54(%), 'body-guard service' 0.12(%), and 'patrol service' 0.21(%) in 'private security', and 'public security' 0.20(%). With regard to the accident frequency rate of organization and population, 'facilities-guard service' is the highest. The accident frequency rate of population in 'facilities-guard service' organization ranges dispersively from 0.20(%) to 11.11(%). Sixthly, the accidented rate of workers having serviced for under one year is 57.6(%). This can mean that the main factor of accidents in Korean Security Industry is the lack of role-understanding and training/education. And another factor can be found on the time of accident occurrence. Many accidents have been occurred on the relaxed points like as just after lunch and morning rush-hour. Lastly, the major advisable facts related to preventing accidents are as follows : The workers who are over fifty years old in 'facilities-guard service' organization need to be educated for preventing accidents ; It is desirable that the training and education to prevent accidents should be practiced in the time of pre-service ; As the style of accidents and the age of the accidented are not same according to major service area('public security' and 'private security' : 'facilities-guard service', 'body-guard service', and 'patrol service'), the plans to prevent accidents must be different and various. However fracture and bruise are general accidents in Korean Security Industry ; Workers must care about traffic accident and violent fall ; It seems that the grouped working with other two persons will reduce accident occurrence possibility rather than individually single working.