• Journal of Convergence for Information Technology
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• v.10 no.3
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• pp.115-125
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• 2020

Problem-Based Learning is the most commonly used teaching method in the field of education as the demand for talented people with creative problem-solving abilities has increased in recent society. In this study, we developed a tool that can simply and regularly measure the learning effects of applying Problem-Based Learning on the classroom. Twenty-two preliminary items for the development were constructed by gathering expert opinions about items collected in existing research of Problem-Based Learning effects measurement. Using this preliminary items, data were collected from 124 students who took the subject-based study. And the validity and reliability were verified through Rash analysis. 11 of 124 students and 1 of 22 items were found to nonconforming and excluded. In addition, the optimal scale for the configuration of this tool was found to be a four-point scale, and the reliability of separation on the subject and the item was found to be excellent. We hope that the assessment tools of Problem-Based Learning effectiveness developed in this study will be actively used to measure learning effectiveness and manage the quality of education.

• Journal of the Korean Institute of Landscape Architecture
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• v.45 no.6
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• pp.160-170
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• 2017

As a monumental building in the form of an arch, an archway has the characteristics of praise and honor. More and more historic, cultural and social connotations are given during the development of history. Four archways that are located on the middle route of the Red Gate Palace in the Mount Tai Scenic Area were chosen for research. Based on a literature review and field investigation with a visual analysis method, the physical attributes, spatial scale, perceptions and functions of the archways were discussed. The results were as follows: The archways in the research area are all made of stone. According to building location, they are classified into two types: Cultural archway and temple archway. Regarding functions, they are divided into symbolic archway, memorial archway and portal archway. From the point of view of form and scale, the Confucius Boarding Archway enjoys a higher standard than the other three. This reflects the importance of Confucian culture on Mount Tai. Regarding spatial scale, the archway becomes the focus in a restrictive linear space by an object-to-object and person-to-object comparison. Visitor experience of crossing the archways is strongly enhanced as it acts as entrance and exit, and it has the function of guiding sight since the arrangement of the archways further extend the line of sight. Couplets and inscriptions on the archways increase a sense of expectation for visitors on their way to the top of Mount Tai.

• Restorative Dentistry and Endodontics
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• v.34 no.3
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• pp.208-214
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• 2009

The purpose of this study was to compare the dye leakage of MTA (mineral trioxide aggregate) apical plug produced by two orthograde placement techniques (hand condensation technique and ultrasonically assisted hand condensation technique). To simulate straight canal, 60 transparent acrylic blocks with straight canal were fabricated. These transparent acrylic blocks were divided into 2 groups (Group C; hand condensation technique (HC) and Group U; ultrasonically assisted hand condensation technique (UAHC)) of 30 blocks with each MTA application method. Each group was divided into 2 subgroups (n=15) with different canal size of #70 (subgroup C70 and subgroup U70) and #120 (subgroup C120 and subgroup U120). After apical plug was created, a wet paper point was placed over the MTA plug and specimen was kept in a humid condition at room temperature to allow MTA to set. After 24 hours, remaining canal space was backfilled using Obtura II. All specimens were transferred to floral form socked by 0.2% rhodamine B solution and stored in 100% humidity at room temperature. After 48 hours, resin block specimens were washed and scanned using a scanner. The maximum length of micro leakage was measured from the scanned images of four surfaces of each resin block using Photoshop 6.0. Statistical analysis was performed with Mann-Whitney U test. Group U of UAHC had significantly lower leakage than Group C of HC in #70-size canal (subgroup U70) (p<0.05).

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.14-15
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• 2010

Recently there has been growing interest in topological insulators or the quantum spin Hall (QSH) phase, which are insulating materials with bulk band gaps but have metallic edge states that are formed topologically and robust against any non-magnetic impurity [1]. In a three-dimensional material, the two-dimensional surface states correspond to the edge states (topological metal) and their intriguing nature in terms of electronic and spin structures have been experimentally observed in bulk Bi1-xSbx single crystals [2,3,4]. However, if we want to know the transport properties of these topological metals, high purity samples as well as very low temperature will be needed because of the contribution from bulk states or impurity effects. In a recent report, it was also shown that an intriguing coupling between the surface and bulk states will occur [5]. A simple solution to this bothersome problem is to prepare a topological metal on an ultrathin film, in which the surface-to-bulk ratio is drastically increased. Therefore in the present study, we have investigated if there is a method to make an ultrathin Bi1-xSbx film on a semiconductor substrate. From reflection high-energy electron diffraction observation, it was found that single crystal Bi1-xSbx films (0${\sim}30\;{\AA}A$ can be prepared on Si(111)-$7{\times}7$. The transport properties of such films were characterized by in situ monolithic micro four-point probes [6]. The temperature dependence of the resistivity for the x=0.1 samples was insulating when the film thickness was $240\;{\AA}A$. However, it became metallic as the thickness was reduced down to $30\;{\AA}A$, indicating surface-state dominant electrical conduction. Figure 1 shows the Fermi surface of $40\;{\AA}A$ thick Bi0.92Sb0.08 (a) and Bi0.84Sb0.16 (b) films mapped by angle-resolved photoemission spectroscopy. The basic features of the electronic structure of these surface states were shown to be the same as those found on bulk surfaces, meaning that topological metals can be prepared at the surface of an ultrathin film. The details will be given in the presentation.

• Korean Journal of Remote Sensing
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• v.26 no.5
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• pp.593-603
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• 2010

Most spatial data acquisition systems employing a set of frame cameras may have suffered from their small fields of view and poor base-distance ratio. These limitations can be significantly reduced by employing an omni-directional camera that is capable of acquiring images in every direction. Bundle Block Adjustment (BBA) is one of the existing georeferencing methods to determine the exterior orientation parameters of two or more images. In this study, by extending the concept of the traditional BBA method, we attempt to develop a mathematical model of BBA for omni-directional images. The proposed mathematical model includes three main parts; observation equations based on the collinearity equations newly derived for omni-directional images, stochastic constraints imposed from GPS/INS data and GCPs. We also report the experimental results from the application of our proposed BBA to the real data obtained mainly in urban areas. With the different combinations of the constraints, we applied four different types of mathematical models. With the type where only GCPs are used as the constraints, the proposed BBA can provide the most accurate results, ${\pm}5cm$ of RMSE in the estimated ground point coordinates. In future, we plan to perform more sophisticated lens calibration for the omni-directional camera to improve the georeferencing accuracy of omni-directional images. These georeferenced omni-directional images can be effectively utilized for city modelling, particularly autonomous texture mapping for realistic street view.

• The Journal of the Korea Contents Association
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• v.18 no.12
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• pp.54-61
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• 2018

The study was to identify the clinical effects of school sandplay group counseling on the emotions and behavior of elementary school students for the first time in Korea. The method of survey is to consult 113 students in the 4th - 6th grade of ${\bigcirc}{\bigcirc}$ elementary school for 10 weeks from March to July 2015. The small group consisted of 10 to 16 children, with one principal counselor and three or four assistant counselors participating, with 40 minutes of treatment, and a total of 12 follow-up sessions, including the Baseline assessment and treatment sessions. It was conducted to 56 male(49.6%) and 57 female(50.4%) students with questionnaires for their sex and age, assessing KCYP results at the point of baseline and post-therapeutic condition. A comparison of the clinical and detailed assessment scale scores of KCYP before and after 12 weeks of Sandplay resulted in a significant effects in improved and reduced symptoms depression of elementary school students after the school sandplay group counseling. School sandplay group counseling is thought to help elementary school students emotional problems and self-esteem.

• Journal of the Korea Convergence Society
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• v.10 no.8
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• pp.37-44
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• 2019

The purpose of this study is to determine the inhibiting factors of dying well for people who want to have a good death. The final respondents in this study were sampled using stratified proportional allocation using a stratified random sampling method, and 1,000 adults aged between 19 and 75 years were selected. The questionnaire used consisted of four items on general characteristics and 20 items related to the inhibiting factors of dying well scored on a 7-point Likert scale. Analysis was conducted using descriptive statistics, correlation analysis, and decision tree analysis. Results showed that, among the inhibiting factors of dying well, "degenerative diseases (such as dementia)" and "loss of control (mental / physical)" scored 5.502 and 5.268 points, respectively; the highest significant positive correlation was found between "bad marital relationship" and "bad relationship with children," followed by "did not receive death education" and "lack of medical policy promotion (dying well)" and "bad relationship with children" and "indifference of others." Considering these findings, it appears that the whole society will make efforts to improve the perception and practice of good death, and life and death education will be expanded if death education for dying well is organized and implemented.

• Journal of Wetlands Research
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• v.23 no.3
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• pp.252-259
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• 2021

Numerous valley waters originating from Mt. Mudeung and flowing into Gwangju Cheon flowed into the confluence-type sewage conduit, the Gwangju Cheon became dry and water quality deteriorated. In this study, a method to create a stream was studied by using the valley water of Mt. Mudeung in the Gwangju cheon that flows into the sewage treatment plant as a water source. Flow and water quality surveys were investigated at four points with meaningful flow quantity. As a result, it showed a flow quantity was 105~2,721 m³/day at each point. And the average water quality was BOD₅ 0.3~1.6 mg/L. If a stream with a flow quantity of 1,500 m³/day is created during the dry season and then flows into the Namgwang bridge of Gwangju cheon, it is predicted that there will be improvements in BOD 7.3%, COD 6.5%, T-P 5.8%, and T-N 5.2%. In addition, it was determined that the load on the flow quantity of the sewage treatment plant due to the inflow of valley water would be reduced, the cost of sewage treatment would be reduced, and it would be the basis for BGN construction by creating waterside amenity in the city.

• The Journal of the Convergence on Culture Technology
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• v.8 no.1
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• pp.469-481
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• 2022

This study is for increasing evacuation safety by analyzing RSET(the required safe escape time) through the arrangement of personnel by floor and by room while evacuating in a Girls' High School Dormitory. For this study, PAPS(Physical Activity Promotion System) results that have not been studied so far were analyzed and reflected in evacuation simulations on the premise that individual student's physical strength can affect evacuation. Based on the PAPS results, four scenarios were applied. In addition, evacuation simulation using the pathfinder program was conducted in two situations: the evacuation route was assigned or not. Scenario 4 was the fastest at 168.5 seconds of RSET in assigning evacuation routes among scenarios. As a result of this study, the arrangement of students focusing on improving their academic ability and student life guidance excluding student physical strength has problem. In order to solve this problem, it is effective to place C group students(low grade on PAPS) on low floors and A group students(high grade on PAPS) on high floors and to assign evacuation routes in each room. In the future, the following ways need to be more studied. A study on how to increase evacuation safety through practical evacuation training, the way of assessing evacuation safety reflecting the lifestyle and physical strength of girls, the evacuation route assignment according to the fire occurrence point, and the method to secure evacuation routes in the event of a fire near stairs or entrances should be conducted.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.35 no.2
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• pp.73-82
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• 2022

The study presents a three-dimensional approach to simulate the nonlinear behavior of a 72 m long Ultra High Performance Fiber Reinforced Concrete (UHPFRC) pre-stressed box girder for a pedestrian bridge in Busan, South Korea. The concrete damage plasticity (CDP) model is adopted to model the non-linear behavior of the UHPFRC material, in which the material properties are obtained from uniaxial compressive and tensile tests. The simulation model based on the proposed stress-strain curve is validated by the results of four-point bending model tests of a 50 m UHPFRC pre-stressed box girder. The results from the simulation models agree with the experimental observations and predict the flexural behavior of the 50 m UHPFRC pre-stressed box girder accurately. Afterward, the validated model is utilized to investigate the flexural behavior of the 72 m UHPFRC pre-stressed box girder. Here, the load-deflection curve, stress status of the girder at various load levels, and connection details is analyzed. The load-deflection curve is also compared with design load to demonstrate the great benefit of the slender UHPFRC box girder. The obtained results demonstrate the applicability of the nonlinear finite element method as an appropriate option to analyze the flexural behavior of pre-stressed long-span girders.