• Journal of The Korean Association of Information Education
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• v.22 no.4
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• pp.501-508
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• 2018

Virtual reality contents can contribute to students' experience in teaching and learning activities, and teachers and students are increasingly interested in using virtual reality in educational settings. For this purpose, We have developed a curriculum designed to teach pre-service teachers Cospaces at the College of Education and analyzed the influence of learners on learning motivation. For the evaluation of this study, a pre- and post-questionnaire was conducted and analyzed. As a result, attention and confidence of learning motivation differ according to gender, and new technology and achievement affect learning motivation.

• The Korean Journal of Ecology
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• v.21 no.5_1
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• pp.449-456
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• 1998

This study was carried out to investigate the characteristics of acid deposition by stemflow, throughfall, rainfall and $SO_{2}$ in the industrial, urban and rural areas where were affected by the acid rain areas air pollution in Pinus thunbergii than Quercus spp. forest. As the stemflow pH in industrial and urban area were lowed that of rural area, the result industrial and urban, and correlation of negative ($r=-0.9415^{**}$) between pH and EC. The concentration of acid ion by stemflow, throughfall, rainfall were high $SO_{4}^{2-}$ ion at industrial areas, especially of $NO_{3}^{-}$ ion at urban areas. The concentration of basic ion all rain fall were high $Ca^{2+},\;Na^{+}$ ion at industrial areas, but there were high $Ca^{2+}$, $Na^{+}$ ion at urban areas. The concentration of $SO_{2}$ at survey areas were high $SO_{2}$ concentration at industrial and urban areas, but there was low at rural areas. There was correlation of negative ($r=-0.8007^{**}$ between pH and $SO_{2}$ concentration at survey areas. Soil acidity was also affected by stemflow and showed sigificantly low pH in industerial and urban areas.

• Journal of Korean Society for Quality Management
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• v.44 no.1
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• pp.77-94
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• 2016

Purpose: This paper reviews Type 1 Gage study, Gage R&R study, and procedure of ISO 22514-7 for assessing a measurement system, and discusses some relationships between the measurement capability indices. Methods: The gage capability index $C_g$ of Type 1 Gage study, precision-to-tolerance ratio PTR of Gage R&R study, and measurement performance ratio $Q_{MS}$ and $Q_{MP}$ of ISO 22514-7 are considered in this paper. Results: This paper derives the relationships between $C_g$ and $Q_{MS}$, PTR and $Q_{MP}$, and $Q_{MS}$ and $Q_{MP}$, respectively, and discusses the acceptance conditions for each procedures. Conclusion: The measurement capability analysis is the first step for the quality improvement of the manufacturing processes. Therefore the result of this study provides a helpful guidelines for assessing the measurement system, enabling proper evaluation of manufacturing processes.

• Journal of Chest Surgery
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• v.18 no.4
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• pp.844-848
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• 1985

Mediastinal tumors which are originated in mediastinum or probably metastasized from other organs have long fascinated the surgeon because of difficulty of diagnosis and treatment. This report is the analysis of the 26 cases of mediastinal tumors, experienced in the Department of the Thoracic and Cardiovascular Surgery, Chosun University Hospital from January 1978 to January 1985. The result are as follows; 1. The age distribution was 10 months to 68 years old and the average mean age was 34.7 years old. 2. Subjective symptom were as follows: Dyspnea [69.2%], Coughing [42.3%], Chest pain [30.8%], Back pain [15.4%] and Numbness of extremities [15.4%]. Objective signs were as follows: Decreased breathing sound [53.3%], Pleural effusion and hemothorax [34.6%], Palpable neck mass [34.6%], SVC Syndrome [19.4%] and Bloody sputum [15.4%]. But, there were no definitive symptoms in 2 cases. 3. The malignant tumors were 19 cases [73.1%]. 4. The germ cell tumors were 2 cases [7.7%], the neurogenic tumor were 3 cases [11.5%], lymphoma were 8 cases [30.8%], thymoma were 2 cases [7.7%], mesenchymal tumor was 1 case [3.8%], cyst was 1 case [3.8%] and carcinoma were 5 cases [19.2%] among the 23 cases, histologically analyzed. 5. The successful complete removal was done in 5 cases among 7 cases of benign tumors. In malignant cases, the surgical removal had been 7 cases and inoperable cases were treated to radiation and chemotherapy.

• Computers and Concrete
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• v.21 no.6
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• pp.727-739
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• 2018

Crack is the most common typical feature of concrete deterioration, so routine monitoring and health assessment become essential for identifying failures and to set up an appropriate rehabilitation strategy in order to extend the service life of concrete structures. At present, image segmentation algorithms have been applied to crack analysis based on inspection images of concrete structures. The results of crack segmentation offering crack information, including length, width, and area is helpful to assist inspectors in surface inspection of concrete structures. This study proposed an algorithm of image segmentation enhancement, named morphological segmentation based on edge detection-II (MSED-II), to concrete crack segmentation. Several concrete pavement and building surfaces were imaged as the study materials. In addition, morphological operations followed by cross-curvature evaluation (CCE), an image segmentation technique of linear patterns, were also tested to evaluate their performance in concrete crack segmentation. The result indicates that MSED-II compared to CCE can lead to better quality of concrete crack segmentation. The least area, length, and width measurement errors of the concrete cracks are 5.68%, 0.23%, and 0.00%, respectively, that proves MSED-II effective for automatic measurement of concrete cracks.

• Atmosphere
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• v.29 no.1
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• pp.53-59
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• 2019

The quality of troposphere ozone in three reanalysis datasets is evaluated with longterm ozonesonde measurement at Pohang, South Korea. The Monitoring Atmospheric Composition and Climate (MACC), European Centre for Medium-Range Weather Forecasts Interim Reanalysis (ERAI) and Modern Era Retrospective-Analysis for Research and Applications version 2 (MERRA2) are particularly examined in terms of the vertical ozone structure, seasonality and long-term trend in the lower troposphere. It turns out that MACC shows the smallest biases in the ozone profile, and has realistic seasonality of lower-tropospheric ozone concentration with a maximum ozone mixing ratio in spring and early summer and minimum in winter. MERRA2 also shows reasonably small biases. However, ERAI exhibits significant biases with substantially lower ozone mixing ratio in most seasons, except in mid summer, than the observation. It even fails to reproduce the seasonal cycle of lower-tropospheric ozone concentration. This result suggests that great caution is needed when analyzing tropospheric ozone using ERAI data. It is further found that, although not statistically significant, all datasets consistently show a decreasing trend of 850-hPa ozone concentration since 2003 as in the observation.

• Journal of Korean Dental Science
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• v.13 no.2
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• pp.59-66
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• 2020

Purpose: The purpose of this study was to investigate the masseter muscle thickness before and after treatment using ultrasound sonography in patients with parafunctional habits. Materials and Methods: From September 2019 to March 2020, a total of 27 patients who visited the Department of Oral and Maxillofacial Surgery at Ewha Womans University Seoul Hospital were collected. The thickness of both masseter muscles was measured using a tablet ultrasound scanner. Statistical analysis was performed by using the IBM SPSS version 26.0 statistical package (IBM Corp) with significance level at 0.05. Result: According to the statistical results, the thickness of the masseter muscle was thicker on the right side than on the left, with no correlation with sex or age. The severity and duration of pain did not have a significant correlation with the thickness of the masseter muscle. Botulinum A toxin injection in the masseter muscle was the most effective way to reduce pain and reduce the thickness of the masseter muscle. Splint treatment also showed some effects in reducing the thickness of the masseter muscle. Conclusion: Based on the findings, it can be claimed that ultrasonography is simple, inexpensive and easily repeatable method to get real-time diagnosis and treatment results for masseter muscles.

• Journal of Positioning, Navigation, and Timing
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• v.12 no.1
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• pp.75-81
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• 2023

In this study, we design an optimized Graphics Processing Unit (GPU)-based GNSS signal processing technique with the goal of designing and implementing a GNSS Software Defined Receiver (SDR) that can operate in real time all-in-view mode under multi-constellation and multi-frequency signal environment. In the proposed structure the correlators of the existing GNSS SDR are processed by the GPU. We designed a memory structure and processing method that can minimize memory access bottlenecks and optimize the GPU memory resource distribution. The designed GNSS SDR can select and operate only the desired GNSS or desired satellite signals by user input. Also, parameters such as the number of quantization bits, sampling rate, and number of signal tracking arms can be selected. The computing capability of the designed GPU-based GNSS SDR was evaluated and it was confirmed that up to 2400 channels can be processed in real time. As a result, the GPU-based GNSS SDR has sufficient performance to operate in real-time all-in-view mode. In future studies, it will be used for more diverse GNSS signal processing and will be applied to multipath effect analysis using more tracking arms.

• Journal of the Korean Society of Safety
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• v.30 no.1
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• pp.137-143
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• 2015

Fire fighter are exposed to the situations which are hard to predict due to continuous and accidental changes which hinder their fire fighting activity. As these threats of safety accident act as fear factors, they are doing insecure fire fighting activities. Therefore, as unclear and abnormal risks of working environment such as the riskiness of expansion of disaster, instability, obstacles of activities, abnormality, urgency, etc. increase, safety accidents are caused. This study analyzes the actual condition of safety and health and awareness of fire fighter who are exposed safety accidents during their fire fighting activities and utilize such result as the basis data to secure safety of fire fighter, keep efficient safety control and prevent accidents. The results of analysis are as follows. As rescue works among all fire-fighting works shows the highest emotional stabilization and the highest post-traumatic stress disorder is shown in fire sergeant level positions, and fire fighters whose working period is 10-15 years, reinforcing safety training to long-term workers is necessary. As the result of survey regarding safety awareness, the highest awareness level was shown in fire sergeant level positions, and fire fighters whose working period is over 20 years, and when it comes to operation of fire fighting equipments, fire-fighting workers and workers having 1-4 years of working period showed high safety awareness. The more serious injury in a fire fighter experienced as the first injury after working as a fire-fighter, the more cause-and-effect relationship was shown between personal physical condition and work, and it is shown as obstacles of fire fighting activities and affects to post-traumatic stress disorder. Moreover, as after-work off duty activities also affect to official disaster, systematic improvement of working environment is required. Occupational medical work compatibility evaluation considering the distinct characteristics of works to secure fire-fighter' health care together with fire-fighting capability is shown to be necessary.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2007.11a
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• pp.249-254
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• 2007

The main bodies of housing markets of today need to carry out a systematic and objective feasibility analysis even from the step of planning in order to succeed in a diverse and complex market environment. Therefore, it is meaningful to understand this housing market environment and propose a necessary model for the feasibility analysis of hosing business. In this vein, the aim of this study was to extract an actual and practical feasibility analysis factor and its importance for housing market, and then present and apply a feasibility analysis factor model to an on-site example, in order to verify the model's validity. For this, the investigator interviewed with and carried out a questionnaire survey of experts in housing development projects. Study findings are as follows:First, the feasibility analysis factor, derived in this study, could provide a ground to evaluate the feasibility of subject projects in the planning of development through an analysis index. Second, when feasibility is under the level of carrying out the projects, it is possible to reexamine the projects through extracting analysis factors of which points are under the standard and via a feedback process for improvable analysis factors. Therefore, the result of applying the feasibility analysis model of this study to actual housing development projects analytically shows that the model could provide a practical evaluation criterion to the person in charge of project development through an analysis index.