• Korean Journal of Construction Engineering and Management
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• v.21 no.6
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• pp.46-55
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• 2020

The maintenance cost for highway pavement is gradually increasing due to the continuous increase in road extension as well as increase in the number of old routes that have passed the public period. As a result, there is a need for a method of minimizing costs through preventative grievance Preventive maintenance requires the establishment of a strategic plan through accurate prediction old Highway pavement. herefore, in this study, the XGBoost among machine learning classification-based models was used to develop a highway pavement damage prediction model. First, we solved the imbalanced data issue through data sampling, then developed a predictive model using the XGBoost. This predictive model was evaluated through performance indicators such as accuracy and F1 score. As a result, the over-sampling method showed the best performance result. On the other hand, the main variables affecting road damage were calculated in the order of the number of years of service, ESAL, and the number of days below the minimum temperature -2 degrees Celsius. If the performance of the prediction model is improved through more data accumulation and detailed data pre-processing in the future, it is expected that more accurate prediction of maintenance-required sections will be possible. In addition, it is expected to be used as important basic information for estimating the highway pavement maintenance budget in the future.

• Journal of Korean Elementary Science Education
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• v.21 no.2
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• pp.213-226
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• 2002

The purpose of this research is to direct the 7th national primary science curriculum to be performed properly. The research is based on the questionnaire to investigate the primary teachers' appreciation of the curriculum. The questions are about the general aspect of the 7th curriculum and special treatises on science curriculum. Questionnaires were distributed to 1000 teachers, and 822 teachers answered them. According to the survey results the teachers' thoughts were as following: First, there must be enough time to develop a new curriculum. It is not desirable to change the old curriculum totally. There should be some continuity between the old and the new curriculum. Second, teachers appreciated that the learning resources and supplements were helpful, and interested students. Teachers thought that If equipment at class or school was not enough. Third, according to them the hierarchical structure of science curriculum was appropriate, but the contents need to be improved. Fourth, most teachers restructured the 7th science curriculum to adapt it to the class and school. They cooperated with one another in teaching science, and applied diverse teaching-learning methods according to the curricular contents and the grade levels. Teachers tried to evaluate all aspects of the students with various methods, but they felt it was hard. They were not active in developing evaluation tools as a team, and in objectifying the information about students. Fifth, teachers felt it was hard to implement the science curriculum according to different levels of the students. Based on the survey of teachers' thoughts, the following can be suggested for successful implementation and reorientation of the curriculum. First, teachers need learning opportunities to appreciate and adapt the 7th curriculum creatively. Second, they need guidances in implementing the different levels of the curriculum, and the information about the appropriate resources for it. Third, we need to control the relative difficulty of the curricular contents, and reduce the hours and quantity of the study. Fourth, we need to improve the school equipment and facilities. Networking and cooperation among education-related institutions are essential for better education. Fifth, it is desirable to develop concrete and diverse teaming models.

• Journal of Trauma and Injury
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• v.26 no.3
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• pp.243-247
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• 2013

Introduction: Surgical treatment of subclavian artery (SA) injury is challenging because approaching the lesion directly and clamping the proximal artery is difficult. This can be overcome by using an endovascular technique. Case 1: A 37-year-old male was drawn into the concrete mixer truck. He had a right SA injury with multiple traumatic injuries: an open fracture of the right leg with posterior tibial artery (PTA) injury, a right hemothorax, and fractures of the clavicle, scapula, ribs, cervical spine and nasal bone. The injury severity score (ISS) was 27. Computed tomography (CT) showed a 30-mm-length thrombotic occlusion in the right SA, which was 15 mm distal to the vertebral artery (VA). A self-expandable stent($8mm{\times}40mm$ in size) was deployed through the right femoral artery while preserving VA flow, and the radial pulse was palpable after deployment. Other operations were performed sequentially. He had a viable right arm during a 13-month follow-up period. Case 2: A 25-year-old male was admitted to our hospital due to a motorcycle accident. The ISS was 34 because of a hemothorax and open fractures of the mandible and the left hand. Intraoperative angiography was done through a right femoral artery puncture. Contrast extravasation of the SA was detected just outside the left rib cage. After balloon catheter had been inflated just proximal to the bleeding site, direct surgical exploration was performed through infraclavicular skin incision. The transected SA was identified, and an interposition graft was performed using a saphenous vein graft. Other operations were performed sequentially. He had a viable left arm during a 15-month follow-up period. Conclusion: The challenge of repairing an SA injury can be overcome by using an endovascular approach.

• Korea journal of population studies
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• v.16 no.2
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• pp.1-23
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• 1993

Korea fertility level has dropped since the 1960's and speed of decline has accelerated in the 1980's. In the resuls, the growth rate reached to less then 1 percent in 1990 and will be $\ulcorner$0 $\lrcorner$ percent growth in 2021. The total population will increase to 50, 586 thousand persons in 2021 then will decrease. With the rapid fertility decline the age structure of Korean population has changed : while the proportion of child population aged 0-14 is decreasing sharply, that of old-age population aged 65 and over is increasing. Because of the recent increase of sex ratio at birth, the sex structure among the young generation has been destorted; the sex ratio at age 0-4 was as high as high as 112.0 in 1990. The effects of these population phenomena on Korean society are the followings: 1) Old age dependency ratio is increasing rapidly and continuously and will be about 40.0 from the 2050's. 2) Because of the rapid decline of the number of births, the absolute number of the major labour force at age 25-34 will decrease after around 2000 and then from the 2010's become less than that in 1990. 3) Since the large fertility defferentials by womens's educational level have continued and the relation between the educational levels of mothers and children are very strong, level has dropped among higher educated women first when the average fertility level has declined in Korea, the average educational level of the children is may be expected to be relatively low and then the future productivity is will be also low, which causes the decline of 'quality of population. 4) When the high sex ratio at birth (over 110 since 1986) continues, number of brides will be short by over 20 percent from the 2010s, which will bring various kinds of social prblems. Therefore, the counter measures in concrete to relieve the heavy problems are recommended as follows: 1) The extention of the birth intervals, which helps to drop the population growth rate at the same level of number of children per women. 2) The positive supports for out-migrants, which helps to reduce the population size without any destortion of age-sex structure. 3) The defferent supports of family planning for the higher and lower classes, which helps to reduce the gaps between different ferility levels of the classes and to keep and improve the quality of population. 4)population education for both students and adults, which helps to minimize the gap between the private and public requirements.

• (The)Study of the Eastern Classic
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• no.68
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• pp.99-144
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• 2017

This paper focused on the narrative and theme of which is one of the different versions of when published in 1910's as a modern printing. Generally researchers regarded different version as a means of research for finding best version. But this paper aimed at the characteristics of different version . This version kept in mind for play(drama), so we could easily find the purpose of change for scenario. 'Yeon-jeong' in is 연정(演訂) in Korean words in Chinese characters. It is sure that this word means that the text considered play(drama). The narrative of also told us that this old novel aimed at the stage. Tendencies are classified four features, first, abundant situation description, second, frequent direct conversation, third, concrete description about direct conversation, fourth, showing poem and appeal for audience. The theme of has an interesting differences in comparison to the group of best version. When main character awakened, this novel showed the most important message. In the group of best version, he awakened to the cloud that he couldn't distinguish anything. But in this novel, cloud didn't appear, in other words, didn't change the scene. Instead, main character realize himself that he changed from Yang-so-yoo to Seong-jin. It is probable that change of process to conclusion aroused reader and audience's sympathy. To sum up, we could know that this novel kept in mind for play(drama).

• (The)Study of the Eastern Classic
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• no.70
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• pp.157-183
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• 2018

Mokjae Lee Samhwan's "MaengHoEum" is the three poems of the Chinese quatrain of 5word 7poetry created according to the previous age. This poem is distinguished from the poem of the general "MaengHoHaeng" series because of it was created in the form of modern-style poetry of series, not a poetry of 5word or 7word or length phrase in a poem. The "MaengHoEum" of MokJae seems to have been built around 1801year when he was 73 years old. Therefore, his "MaengHoEum" can be called an allegory poetry or a society poetry and his poetry can be said that it was created under the criticism of the corrupt political power of the contemporary society, and the 'fierce tiger' which appeared in his poem refers to the factions of Noron Byek line which was the ruling power at that time. However, if you look at the "MaengHoEum" of MokJae, you will see a criticism of the real world, but the feeling is not intense or the description is not concrete. Although his poetry depicts the absurdity of the present reality, but he does not show positive criticism of reality or strong resistance. This characteristic, which can be seen in his poem "MaengHoEum", is the result of the study he pursued for the his life and is thought to be due to the weight of reality. The contradictions of the time of the Mokjae were never silent to him, but on the other hand he could not reveal his own struggle on the surface of the poem. Between his descendants, influenced by his actions, and the stinging gaze watching him, he had no choice but to end his feelings internally.

• The Journal of Internal Korean Medicine
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• v.28 no.1
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• pp.47-67
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• 2007

Objectives : This study was aimed to investigated the warning signs and its relationship with the other characteristics in acute stroke patients. Methods : 225 acute stroke patients were recruited at the Department of Cardiovascular and Neurologic Diseases (Stroke Center) of Kyung Hee University Oriental Hospital from October 2005 to September 2006. We evaluated their stroke type with brain MRI, their warning signs, and general characteristics such as age, sex, past history, risk factors, etc. Results : 225 subjects were included in the final analysis. In the subjects' general characteristics, the most common etiology of stroke was small vessel occlusion. In the assessment of the subjects' warning signs, the frequency of tension felt at the cervical area was highest followed by blepharospasm, sensory dysfunction (one side of numbness, tingling sensation, dead sensation), one side paralysis or weakness, etc. After analyzing etiology, cerebral hemorrhage had more facial spasm sign and hypertension than cerebral infarction. On the other hand, cerebral infarction had more diabetes and sensory dysfunction (one side of numbness, tingling sensation, dead sensation) than cerebral hemorrhage. Among stroke locations, subjects with their brain lesion in the cortex had more warning sings of motor dysfunction such as one side paralysis, or weakness. Multiple lesions showed a close relationship with smoking habit and were more common in males than in females. The under 65 years old group were more commonly associated with alcohol consumption, accidental mental stress and blepharospam than the over 65 years old group. In the group of under 65 years old, males more commonly had lesions in occipital lobe, alcohol consumption and smoking habit than females. Otherwise, females more commonly had vision dysfunction and blepharospasm than males. In the group of over 65 years old, males more commonly had cortex lesion than females. On the other hand, Females more commonly had accidental mental stress than males. Conclusions : We observed various warning signs and their distribution in acute stroke patients. The subjects' brainlesions and their etiology seemed to affect the features of the warning signs. Hypertension, diabetes and hyperlipidemia were also related to etiology of stroke and some habitual problems such as smoking and drinking seemed to reduce the age of stroke ictus. Although a concrete conclusion can hardly be drawn from this study, it reminds physicians of the importance of warning signs which appear among their patients.

• Journal of Aquaculture
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• v.20 no.4
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• pp.270-277
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• 2007

White spot syndrome virus (WSSV) which is the most serious threat to cultured shrimp around the world has given enormous economic damages to shrimp culture industry every year since it was found from the shrimp ponds in the west coast of the South Korea in 1993. WSSV has strong infectivity as well as virulence and it can be rapidly transmitted among shrimps in ponds by cannibalism of infected ones. Polyculture of shrimps with carnivorous fish has been applied in commercial shrimp farms to suppress or delay the viral outbreak because the fish may selectively eat the moribund shrimps infected by virus. To determine the selective predatory effect of a carnivorous fish, river puffer Takifugu obscurus on white shrimp Litopenaeus vannamei, polyculture trials in laboratory scale of WSSV-infected and non-infected shrimps with river puffer were conducted in concrete round tanks of $28.26\;m^2$ in surface area as followings: 1) juvenile shrimps (B. W. 0.62 g) with 5 months old puffer (B. W. 11.60 g) cultured for 8 days, and 2) sub-adult shrimps (B. W. 6.84 g) with 16 months old puffer (B. W. 85.82 g) cultured for 5 days in order to know the effects according to size difference of cultured animals. In polyculture of juvenile shrimp with 5 months old puffer, survival rates of infected and non-infected shrimps were 46.0% and 89.1% respectively and in that of sub-adult shrimp with 16 months old puffer those were4% and 48% respectively. The results showed that puffer tends to selectively prey on virus infected shrimps among infected and non-infected ones in a limited space with although there is difference in predatory rate with age and density of animals. Regardless of different densities and ages of animals as well as health condition of shrimps, however, there were low differences in daily biomass of shrimp consumed per kg body weight of puffer. This finding suggests that puffer preys on healthy shrimps when moribund shrimps were not sufficient. Therefore, farmers should consider the total biomass of puffer as well as density and stocking time when they stock puffer into shrimp ponds for polyculture.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.10 no.1
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• pp.72-81
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• 2007

This study mainly aims at suggesting plans applicable to the outdoor of environment-friendly communities in Korea by leveraging more natural conditions and materials when creating an outdoor biotop for an environment-friendly community and generating material types and development techniques enabling a natural circulation system. To this end, materials used in the outdoor of environment-friendly communities and traditional residential areas in Korea and biotop materials found in natural areas were examined. First, when the case examples of environment-friendly communities were reviewed, biotop spaces and materials that may function as habitats were hardly found. Materials used in biotop were mainly man-made structures made of artificial or processed materials, such as concrete, stones, bricks, woods and steels. Meanwhile, the outdoor space of traditional Korean villages had stone walls, soil walls, rock piles and composite piles, which composed of natural materials such as rocks, soil and plants, that naturally formed porous spaces along with the introduction of plants and provided habitats for a variety of insects. In natural areas, naturally created biotop spaces, such as rock piles, log piles, old tree deployment, branch piles, hay stacks and defoliated leaves, were found. Meanwhile, when spaces and materials available for biotop creation were reviewed to create an environment-friendly residential complex, they were divided into fences and hedges, green spaces between parks and residential buildings, ponds and waterscape spaces, zones separating pedestrian walks and roadways, breast walls and slope boundary, plant box and pergola. For each space, materials used for creating biotops and that were found in traditional Korean residential areas and natural areas were applied and suggested.

• Particle and aerosol research
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• v.13 no.1
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• pp.1-10
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• 2017

Accurate prediction of size, shape and velocity of a bubble rising through a liquid pool is very important for predicting the particulate removal efficiency in pool scrubbing, for designing engineering safety features to prepare for severe accidents in nuclear power plants, and for predicting the emission of fission products from MCCI (molten core-concrete interaction) process during severe accidents. In this review article, previous studies on the determination of the size, shape and rising velocity of a bubble in liquid are reviewed. Various theoretical and parameterization formulas calculating the bubble size, shape and velocity from physical properties of liquid and gas flowrate are compared. Recent studies tend to suggest simple parameterizations that can easily determine the bubble shape and rising velocity without iteration, whereas iteration has to be performed to determine the bubble shape and velocity in old theories. The recent parameterizations show good agreement with measured data obtained from experiments conducted using different liquid materials with very diverse physical properties, proving themselves to be very useful tools for researchers in related fields.