• Journal of the korean academy of Pediatric Dentistry
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• v.35 no.1
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• pp.92-101
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• 2008

The purpose of this study was to investigate the dental caries prevalence and occlusion pattern of children with deciduous dentition in Chonnam seashore area. Two thousand two hundred seventy two kindergarten children ranged 3 to 5 years of age were examined. The obtained results were as follows : 1. The rate of children with caries experience(dmf rate) in deciduous teeth was 66.8% at 3 years of age, 77.7% at 4 years of age, and 83.5% at 5 years of age and showed no significant gender differences(p>0.05). 2. The mean number of decayed, missing, filled deciduous teeth(dmft index) was 3.62 at 3 years of age, 4.73 at 4 years of age, and 5.96 at 5 years of age and showed no significant gender differences(p>0.05). 3. Most of the caries-prevailed tooth was mandibular 2nd primary molar and showed 39.48% at 3 years of age, 49.73% at 4 years of age, and 63.85% at 5 years of age. 4. The caries-experienced teeth in order were as follows : mandibular 2nd primary molar with 52.34%, mandibular 1st primary molar with 45.61%, maxillary 2nd primary molar with 38.81%, and maxillary primary central incisor with 38.86%, respectively. 5. In sagittal primary molar relationship, Class 1 occlusion pattern was 53.26%, Class 2 pattern was 1.41% and Class 3 pattern was 30.02%, respectively. Right Class 2 and Left Class 3 pattern was not observed.

• English Language & Literature Teaching
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• v.17 no.2
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• pp.19-37
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• 2011

This study examines a Korean elementary school EFL teacher's practice of teacher-based assessment (TBA), a subject which has been little researched despite the authorities' strong call for its implementation. The classroom interactions for TBA were observed and audio-recorded in eight fifth-grade classes between March and June 2010. Additionally, the teacher and students were interviewed in a semi-structured way. The results showed that the teacher used three types of TBA: assessment of individual students on different topics, assessment of the entire class on the same topic, and assessment of individual students on the same topic. Due mainly to time constraints during class time and classroom management issues, the teacher preferred implementing the first two types of TBA. During the practice of the types, the teacher provided prompts or posed questions in ways that elicited responses which were short in length and easy. Although the third type of TBA was perceived by both the teacher and students as helping students enhance their EFL proficiency and was the most favored by the students, it was viewed by the teacher as having the potential of causing classroom management difficulties. Based on the findings, a number of implications are suggested.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.14 no.9
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• pp.3797-3822
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• 2020

The inspection of cracks on the surface of tunnel linings is a common method of evaluate the condition of the tunnel. In particular, determining the thickness and shape of a crack is important because it indicates the external forces applied to the tunnel and the current condition of the concrete structure. Recently, several automatic crack detection methods have been proposed to identify cracks using captured tunnel lining images. These methods apply an image-segmentation mechanism with well-annotated datasets. However, generating the ground truths requires many resources, and the small proportion of cracks in the images cause a class-imbalance problem. A weakly annotated dataset is generated to reduce resource consumption and avoid the class-imbalance problem. However, the use of the dataset results in a large number of false positives and requires post-processing for accurate crack detection. To overcome these issues, we propose a crack detection method using a ternary classifier. The proposed method significantly reduces the false positive rate, and the performance (as measured by the F1 score) is improved by 0.33 compared to previous methods. These results demonstrate the effectiveness of the proposed method.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.6
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• pp.2527-2545
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• 2016

Measuring the similarity of given samples is a key problem of recognition, clustering, retrieval and related applications. A number of works, e.g. kernel method and metric learning, have been contributed to this problem. The challenge of similarity learning is to find a similarity robust to intra-class variance and simultaneously selective to inter-class characteristic. We observed that, the similarity measure can be improved if the data distribution and hidden semantic information are exploited in a more sophisticated way. In this paper, we propose a similarity learning approach for retrieval and recognition. The approach, termed as LDA-FEK, derives free energy kernel (FEK) from Latent Dirichlet Allocation (LDA). First, it trains LDA and constructs kernel using the parameters and variables of the trained model. Then, the unknown kernel parameters are learned by a discriminative learning approach. The main contributions of the proposed method are twofold: (1) the method is computationally efficient and scalable since the parameters in kernel are determined in a staged way; (2) the method exploits data distribution and semantic level hidden information by means of LDA. To evaluate the performance of LDA-FEK, we apply it for image retrieval over two data sets and for text categorization on four popular data sets. The results show the competitive performance of our method.

• Journal of the Korean Institute of Educational Facilities
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• v.5 no.2
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• pp.57-66
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• 1998

The present, there are no evident standards about facilities of minimum-sized kindergarten and lower grades elementary school. So, there are many serious obstacles that related laws and regulations, planning for facilities and scales in this country. Accordingly, this study proposed the concept, type, and size of minimum-sized kindergarten and lower grades elementary school, in case big cities of high density. 1. The concept of minimum-sized kindergarten and lower grades elementary school is defined to the large scale school and class, that integration of children of kindergarten into lower grades elementary school. 2. The type of minimum-sized kindergarten and lower grades elementary school is classified into branch school type and detached school type. The former is located in the main elementary school, The latter is separated from the main elementary school. And each type is classified into singleness case and attached case. 3. The number of students per minimum-sized kindergarten and lower grades elementary school is hold from two hundred children to three hundred children in 12 classes, but suitability is from one hundred to two hundred children. And class sizes proposed $20{\sim}25$ children in minimum-sized kindergarten and $25{\sim}30$ children in lower grades elementary school.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.05a
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• pp.442-447
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• 2007

A very abnormal vibration was occurred at the LP(low pressure) turbine continuously during the pre-operation for a 550MW class USC(ultra super critical) steam turbine. This vibration was initiated at the rotating speed of about 3,450rpm and then the vibration amplitude was highly increased the number by $2{\sim}3$ times with the increase of the rotating speed to the rated speed(3,600rpm). In this paper, this abnormal vibration named spike vibration. This spike vibration was caused by the rubbing between the rotating bucket tip seal and the Lower Half of spill strip. Also, this paper presents the mechanism of the spike vibration and the proper method to eliminate this abnormal vibration problem. This result would be good practice to find the solution of similar high vibration in the USC steam turbines for power plant as well as industrial rotating machineries.

• Steel and Composite Structures
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• v.26 no.4
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• pp.439-452
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• 2018

This paper presents experimental and numerical study on buckling behaviors and hysteretic performance of Class 1 H-shaped steel beam subjected to cyclic pure bending within the scope of ultra-low cycle fatigue (ULCF). A loading device was designed to achieve the pure bending loading condition and 4 H-shaped specimens with a small width-to-thickness ratio were tested under 4 different loading histories. The emphasis of this work is on the impacts induced by local buckling and subsequent ductile fracture. The experimental and numerical results indicate that the specimen failure is mainly induced by elasto-plastic local buckling, and is closely correlated with the plastic straining history. Compared with monotonic loading, the elasto-plastic local buckling can occur at a much smaller displacement amplitude due to a number of preceding plastic reversals with relative small strain amplitudes, which is mainly correlated with decreasing tangent modulus of the material under cyclic straining. Ductile fracture is found to be a secondary factor leading to deterioration of the load-carrying capacity. In addition, a new ULCF life evaluation method is proposed for the specimens using the concept of energy decomposition, where the cumulative plastic energy is classified into two categories as isotropic hardening and kinematic hardening correlated. A linear correlation between the two energies is found and formulated, which compares well with the experimental results.

• Journal of Advanced Navigation Technology
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• v.15 no.6
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• pp.1126-1131
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• 2011

As the recent paradigm of education changes to become learner-centered, there is an increasing interest in project based class as one of new teaching models. Universities are accepting this change and aiming at fostering human resources of next generations, who are able to create creative changes, and studies are being actively conducted to that end. This study suggested a learner-centered teaching model which minimizes intervention of teachers in conducting projects of main text contents in designed subjects. This study suggested support system for the suggested model project-based class, team organization method, various interaction methods of learners, and team work monitoring method of teachers. And the suggestions were designed and realized through project management applications using smart phones which are being used by a rapidly growing number of people recently.

• Journal of Chest Surgery
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• v.26 no.3
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• pp.191-195
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• 1993

Among 25 consecutive cases having undergone mitral valve surgery between March 1991 and June 1992 in Gill General Hospital, 11 patients[44%] who had undergone mitral valve reconstruction using prosthetic rings is evaluated and presented. Patients` mean age is 43 + 19 years[range:16-72], and they are consisted with 4 males and 7 females. Mitral valve insufficiency is due to degenerative disease in 6 cases[55%] and rheumatic disease in 5 patients[45%]. Carpentier`s functional classification I is 2 cases, II is 6 cases, and III is 2 cases. Surgical techniques include prosthetic ring annuloplasty[11 patients, 100%], chorda shortening[6, 55%], leaflet mobilization[4,36%], new chorda formation[2, 18%], chorda transposition[1, 9%] commissurotomy[3, 27%], and papillary muscle splitting[3, 27%]. Average number of mitral anatomic lesions per patient are 2.7 and we used average 2.8 procedures upon mitral valve apparatus per patient. There were no surgical mortality and no late valve related admission during the mean follow up period of 17 months. The mean functional class[NYHA] is 2.81 preoperatively and improved to 1.10 postoperatively. Doppler echocardiography showed much improvement from grade II MR [1 case], grade III MR [1 case] and 9 cases of grade IV MR to 6 cases of patients showed no MR, only trace MR in 4 cases, and grade I MR was found only in one patient with NYHA functional class II postoperatively. The postoperative mean mitral valve area is $2.10+0.28cm^2$. We conclude that mitral reconstruction is a predictable and stable operation.

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
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• v.14 no.1
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• pp.8-15
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• 2018

The purpose of this study was to analyze the energy consumption according to the HVAC systems in 122 elementary schools. To do this, we classified schools according to the HVAC systems. Selected schools were classified to the following groups by the HVAC equipments: EHP, EHP and GHP together and GHP. In addition we divided schools by the number of classes. The main results are as follow: 1) Annual average energy consumption at schools was about 300~900(kWh/students), $30{\sim}50(kWh/m^2)$, 9,000~29,000((kWh/class) 2) The smaller schools, the higher the energy consumption per class; energy usage of 10~19 classes's schools were approximately 3 times higher than 40 classes's schools. 3) Schools where the EHP was installed had the lowest energy costs and energy usage. The difference in energy costs was lower than the difference in energy usage because of the fuel price and the ratio of energy sources.