• Korean Journal of Social Welfare
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• v.53
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• pp.75-104
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• 2003

This study was performed to analyze the process and develop the pattern of school dropout in the context of the Korean educational systems. Participants were 30 adolescents experiencing dropout one more times and their age ranged from 16 to 23. A major category derived and analysed from a grounded theory method of Strauss and Corbin(1990). The qualitative analysis indicated that dropout is contradictory experiences in Korea. Because it is emancipation from various distress of school systems as well as loss of various benefit as students, Main causes of dropout were identity problems, school frustrations(failure in school achievements), environmental disadvantaged and delinquencies. Sometimes these various causes are emerged at the same time. Most important condition of context which was decided was whether dropout was voluntary and considered. After dropout from school, it was important if there were resources such as emotional and informative supports. Especially informative support was critical to adjust after dropout. Dropout experience was divided largely into 4 patterns such as type of 'searching the identity', 'being disorganized', 'escaping' and 'frustration'. In chronological analysis resulted in 4 stages including 'stage I. loss of motivation', 'stage II. escaping from school', 'stage III. trial and error', 'stage IV changing the meaning of dropout in the life.

• Tuberculosis and Respiratory Diseases
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• v.61 no.5
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• pp.479-483
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• 2006

Acute fibrinous and organizing pneumonia (AFOP) is a histological pattern consisting of prominent intra-alveolar fibrin and organizing pneumonia, with out hyaline membranes or prominent eosinophilia. The clinical manifestations of AFOP resemble those of acute lung injury such as acute interstitial pneumonia (AIP). However, the classic histological patterns of AFOP differ from diffuse alveolar damage (DAD), bronchiolitis obliterans with organizing pneumonia (BOOP) or acute eosinophilic pneumonia (AEP). The characteristic intra-alveolar fibrin ball and lack of classic hyaline membrane are the predominant histological features of AFOP. Although some reports suggest that its clinical course is less catastrophic than DAD, the clinical entity that distinguishes AFOP from DAD has not been established. We present a case of pathologically demonstrated AFOP in a 79-year-old man. The radiological findings of our case were similar to those of DAD, presented with diffuse bilateral lung infiltrations. However, despite the rapid development of respiratory failure, the patient had a better response and outcome to steroid therapy than what would be expected for DAD.

• Journal of the Korea institute for structural maintenance and inspection
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• v.24 no.3
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• pp.80-86
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• 2020

In the fabrication process of inverted multi-tee (IMT) slabs, concrete has to be poured twice due to its shape, which is a huge disadvantage as a precast member. To overcome this, a new technique for manufacturing IMT slabs using a slipform method has been recently developed. In this study, flexural and shear tests were carried out to investigate the structural performances of inverted multi-tee (IMT) slabs manufactured using slipform method. To this end, one flexural specimen and two shear specimens with topping concrete were fabricated, and their failure modes and crack patterns, and the slips that occurred between the precast slab and topping concrete were measured and analyzed in detail. In addition, the flexural and shear strengths of the specimens were evaluated by utilizing the structural design code, and a shear strength estimation method, which is suitable for composite IMT slabs with different concrete properties, was proposed for practical design. The IMT slab satisfied the nominal flexural strength calculated by the current design code, and the proposed method provided a good estimation of the shear strength of the specimens.

• Journal of the Korean Recycled Construction Resources Institute
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• v.7 no.3
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• pp.271-278
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• 2019

The corrosion of reinforcements embedded in concrete causes severe deterioration in reinforced concrete structures. As a countermeasure, epoxy coated reinforcements are used to prevent corrosion of reinforcements. When epoxy coated bars are used, the resistance of corrosion is excellent, but epoxy coating on the bars have a disadvantage of reduction in bond capacity comparing to that of normal bars. Therefore, it is necessary to confirm the bond performance of epoxy coated reinforcements through experimental and analytical methods. Bond behaviors of epoxy coated bars for various diameters of 13 and 19mm and thicknesses of cover concrete of 3 types(ratio of cover to bar diameter) are examined. As the diameters of the epoxy coated bars increase, the difference of bond strength between epoxy coated and uncoated bars also increases and damage patterns showed pull out failure. In addition, finite element analysis was performed based on the bond-slip relationship obtained by direct pullout test and compared with the flexural test results. It is considered that flexural member test is more useful than pullout test for simulating the behavior of actual structure.

• Journal of Korean Neurosurgical Society
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• v.62 no.1
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• pp.96-105
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• 2019

Objective : The aims in the management of thoracolumbar spinal fractures are not only to restore vertebral column stability, but also to obtain acceptable alignment of the thoracolumbar junction (T-L junction) to prevent complications. However, insufficient surgical correction of the thoracolumbar spine would be likely to cause late progression of abnormal kyphosis. Therefore, we identified the surgical factors that affected unfavorable radiologic outcomes of the thoracolumbar spine after surgery. Methods : This study was conducted in a single institution from January 2007 to December 2013. A total of 98 patients with unstable thoracolumbar spine fracture were included. In these patients, fixation was done through transpedicular screws with rods by three surgical patterns. We reviewed digital radiographs and analyzed the images preoperatively and postoperatively during follow-up visits to compare the change of the thoracolumbar Cobb angle with radiologic parameters and clinical outcomes. The unfavorable radiologic group was defined as the patients who were measured as having greater than 20 degrees of thoracolumbar Cobb angle on the last follow-up, or who underwent kyphotic progression of thoracolumbar Cobb angle greater than 10 degrees from the immediate postoperative state to final follow-up, or who had overt instrument failure with/without additional surgery. We assessed the risk factors that affected the unfavorable radiologic outcomes. Results : We had 43 patients with unfavorable radiologic outcomes, including 35 abnormal thoracolumbar alignments and 14 instrumental failures with/without additional surgery. The multivariate logistic regression test showed that immediate postoperative T-L junction Cobb angle less than 10.5 degrees was a statistically significant risk factor, as well as the presence of osteoporosis (p=0.017 and 0.049, respectively). Conclusion : Insufficient correction of thoracolumbar kyphosis was considered to be a major factor of an unfavorable radiological outcome. The spinal surgeon should consider that having a T-L junction Cobb angle larger than 10.5 degrees immediately after surgery could result in an unfavorable radiological outcome, which is related to a poor clinical outcome.

• Journal of Korean Society on Water Environment
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• v.36 no.6
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• pp.546-558
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• 2020

While industrialization has provided in abundance, the pollution it creates has caused untold damage to the environment, increasing the frequency and severity of natural disasters through changes in global climate patterns. The World Risk Forum's (WEF) World Risk Report presented the results of a survey of experts from around the world detailing the most influential risk factors over the next decade. Notably, the failure to respond to climate change ranked first and the global water crisis third. The extreme drought in the western Chungnam province was unexpected in 2016. At the time, the water level of Boryeong Dam was drastically decreased due to receiving less than half the average recorded rainfall in the region that year. The Boryeong Dam diversion pipeline has the capacity to solve the water shortage problem between these two regions by providing water from Geumgang to the western part of Chungnam, including Boryeong City. Current weather trends suggest drought is likely to continue in western Chungnam, which uses the Boryeong Dam as an intake source. This makes it necessary to operate Boryeong Dam diversion pipeline in an efficient and effective manner. SWAT is a watershed scale model developed to predict the impact of land management practices on water. The SWAT model was used in this study to evaluate the adequacy of the Boryeong Dam diversion pipeline operational plan by comparing it to present Boryeong Dam diversion pipeline operation. By investigating the number of days required to reach each reservoir stage, we determined that the number of days required to reach the boundary stage was less than that of the current operation. This determination accounts for the caveats that the Boryeong Dam waterway was not operated and only one pump will be operated from October to May of next year. As our results suggest, the most stable operation scenario is to operate two pumps at all times. This can be accomplished by operating two pumps from the caution stage to increase the number of pumps whenever the stage is raised. In addition to the stable operation of the Boryeong Dam pipeline, policy considerations are required with regard to imposing a water use charge on users of the Boryeong Dam region.

• Structural Engineering and Mechanics
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• v.83 no.4
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• pp.495-513
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• 2022

This paper aims to study the fracture mechanism of rocks under the 'u'shape cutters considering the effects of crack (pre-existing crack) distances, crack spacing and crack inclination angles. The effects of loading rates on the rock fragmentation underneath these cutters have been also studied. For this purpose, nine experimental samples with dimensions of 5 cm×10 cm×10 cm consisting of the non-persistent cracks were prepared. The first three specimens' sets had one non-persistent crack (pre-existing crack) with a length of 2 cm and angularity of 0°, 45°, and 90°. The spacing between the crack and the "u" shape cutter was 2 cm. The second three specimens" set had one non-persistent crack with a length of 2 cm and angularity of 0°, 45°, and 90° but the spacing between pre-existing crack and the "u" shape cutter was 4 cm. The third three specimens'set has two non-persistent cracks with lengths of 2 cm and angularity of 0°, 45° and 90°. The spacing between the upper crack and the "u" shape cutter was 2 cm and the spacing between the lower crack and the upper crack was 2 cm. The samples were tested under a loading rate of 0.005 mm/s. concurrent with the experimental investigation. The numerical simulations were performed on the modeled samples with non-persistent cracks using PFC2D. These models were tested under three different loading rates of 0.005 mm/s, 0.01 mm/sec and 0.02 mm/sec. These results show that the crack number, crack spacing, crack angularity, and loading rate has important effects on the crack growth mechanism in the rocks underneath the "u" shape cutters. In addition, the failure modes and the fracture patterns in the experimental tests and numerical simulations are similar to one another showing the validity and accuracy of the current study.

• Journal of Korean Elementary Science Education
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• v.41 no.1
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• pp.14-29
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• 2022

The purpose of this study is to investigate the components of scientific attitude by some learning topics in the 3rd~6th grade science textbooks that the pre-service elementary school teachers judge to be teachable in class and the educational effects of this analysis activity for the pre-service teachers. The several results of this study are as follows: The pre-service teachers responded that, for all learning topics, they could teach diverse components of scientific attitude and the number of components expressed in their responses is more than the components specified in the teacher's guides. Among the components of scientific attitude, 'curiosity', 'open-mindedness', 'respect for evidence', and 'objectivity' showed relatively high possibility of teaching, while 'honesty', 'collaboration', 'positive acceptance of failure', 'critical mind' and 'suspension of judgment' showed relatively low possibility of teaching. The responses that pre-service teachers judged to be teachable also showed similar patterns in the number of components of scientific attitude and the rate of the components between the learning topics of the 3~4th grades and the learning topics of the 5~6th grades. In addition, this pre-service teachers' analysis activity on the components of scientific attitude by learning topics in science textbooks suggested educational effects such as 'the deep understanding of the components of scientific attitude', 'the understanding and applying the components of scientific attitude in the context of science class', and so on.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2022.05a
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• pp.165-167
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• 2022

The proportion of cat cats among companion animals has been increasing at an average annual rate of 25.4% since 2012. Cats have strong wildness compared to dogs, so they have a characteristic of hiding diseases well. Therefore, when the guardian finds out that the cat has a disease, the disease may have already worsened. Symptoms such as anorexia (eating avoidance), vomiting, diarrhea, polydipsia, and polyuria in cats are some of the symptoms that appear in cat diseases such as diabetes, hyperthyroidism, renal failure, and panleukopenia. It will be of great help in treating the cat's disease if the owner can recognize the cat's polydipsia (drinking a lot of water), polyuria (a large amount of urine), and frequent urination (urinating frequently) more quickly. In this paper, 1) Efficient version of DeepLabCut for posture prediction running on an artificial intelligence server, 2) yolov4 for object detection, and 3) LSTM are used for behavior prediction. Using artificial intelligence technology, it predicts the cat's next, polyuria and frequency of urination through the analysis of the cat's behavior pattern from the home CCTV video and the weight sensor of the water bowl. And, through analysis of cat behavior patterns, we propose an application that reports disease prediction and abnormal behavior to the guardian and delivers it to the guardian's mobile and the main server system.

• Journal of the Korean Geotechnical Society
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• v.24 no.5
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• pp.65-78
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• 2008

In case of cut-slopes or shallow-depth tunnels, sliding along with discontinuities or rotation could play a critical role in judging stability. Although numerical analysis is widely used to check the stability of these cut-slopes and shallow-depth tunnels in early design process, common analysis programs are based on continuum model. Performing continuum model analysis regarding discontinuities is possible by reducing overall strength of jointed rock mass. It is also possible by applying ubiquitous joint model to Mohr-Coulomb failure criteria. In numerical analysis of cut-slope, main geotechnical properties such as cohesion, friction angle and elastic modulus can be evaluated by empirical equations. This study tried to compare two main systems, RMR and GSI system by applying them to in-situ hazardous cut-slopes. In addition, this study applied ubiquitous joint model to simulation model with inputs derived by RMR and GSI system to compare with displacements obtained by in-situ monitoring. To sum up, numerical analysis mixed with GSI inputs and ubiquitous joint model proved to provide most reliable results which were similar to actual displacements and their patterns.