• KIPS Transactions on Software and Data Engineering
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• v.10 no.2
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• pp.45-56
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• 2021

In platoon driving, several autonomous vehicles communicate to exchange information with each other and drive in a single cluster. The platooning technology has various advantages such as increasing road traffic, reducing energy consumption and pollutant emission by driving in short distance between vehicles. However, the short distance makes it more difficult to cope with an emergency accident, and accordingly, it is difficult to ensure the safety of platoon driving, which must be secured. In particular, the unexpected situation, i.e., variability that may appear during driving can adversely affect the safety of platoon driving. Because such variability is difficult to predict and reproduce, preparing safety guards to prevent risks arising from variability is a challenging work. In this paper, we studied a simulation method to avoid the risk due to the variability that may occur while platoon driving. In order to simulate safe platoon driving, we develop diverse scenarios considering the variability, design and apply safety guards to handle the variability, and extends the detail functions of VENTOS, an open source platooning simulator. Based on the simulation results, we have confirmed that the risks caused form the variability can be removed, and safe platoon driving is possible. We believe that our simulation approach will contribute to research and development to ensure safety in platoon driving.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.24 no.10
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• pp.1331-1340
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• 2020

Object detection in maritime means that the captain detects floating objects that has a risk of colliding with the ship using the computer automatically and as accurately as human eyes. In conventional ships, the presence and distance of objects are determined through radar waves. However, it cannot identify the shape and type. In contrast, with the development of AI, cameras help accurately identify obstacles on the sea route with excellent performance in detecting or recognizing objects. The computer must calculate high-volume pixels to analyze digital images. However, the CPU is specialized for sequential processing; the processing speed is very slow, and smooth service support or security is not guaranteed. Accordingly, this study developed maritime object detection software and implemented it with FPGA to accelerate the processing of large-scale computations. Additionally, the system implementation was improved through embedded boards and FPGA interface, achieving 30 times faster performance than the existing algorithm and a three-times faster entire system.

• Journal of Korean Library and Information Science Society
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• v.52 no.2
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• pp.145-166
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• 2021

The study was aimed at verifying the effectiveness of Book-Coding reading education as a reader activity of older elementary school children at a time when high-dimensional thinking abilities were formed. To this end, 30 fifth-grade children of N Elementary School in N-si, Gyeonggi-do, comprised of 15 students from a reading education program using Book-Coding, and 15 students from a reading comprehension program, and applied the reading education program over a total of 12 sessions. The main results of the study are summarized as follows. First, when the effects of the convergence reading education program using Book-Coding on the logical thinking ability of the students in the upper grades in the elementary school were analyzed, all the six sub-factors of logical thinking ability, that is, conservation logic, proportional logic, variable controlling logic, probabilistic logic, correlational inference logic, and combinational logic, were proved to have statistically more meaningful difference than the group writing a book report. Second, the analysis result of the influence of the convergence reading education program using Book-Coding on the creativity of the students in the upper grades of the elementary school showed that all the 13 elements of curiosity, persistence, effectiveness, independence, adventurousness, openness, knowledge, imagination, originality, sensitivity, fluency, flexibility, and accuracy were statistically meaningfully different compared to the book report group. Third, when it was analyzed how the convergence reading education program using Book-Coding affected the creative personality of the elementary school students, all the six factors of curiosity, task commitment, independence, awareness of risk, and openness of thinking, and aesthetics were found out to have a statistically more meaningful difference than the group that wrote a book report.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.42 no.6
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• pp.825-836
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• 2022

Micropiles can be used to support additional load in extended building structures. However, their use brings about a risk of exceeding the bearing capacity of existing piles. In this study, pre-compression was applied to distribute the load of an existing building to micropiles, and an indoor loading test was performed to confirm the structural applicability of a wedge-type anchorage device designed to improve its capacity. According to the test results, the maximum strain of the anchorage device was 0.63 times that of the yield strain, and the amount of slip generated at the time of anchorage was 0.11 mm, satisfying structural standards. In addition, using MIDAS GTS, a geotechnical finite element analysis software, the effect of the size of the pre-compression, the thickness of the soil layer, and the ground conditions around the tip on the reaction force of the existing piles and micropiles were analyzed. From the numerical analysis, as the size of the pre-compression load increased, the reaction force of the existing pile decreased, resulting in a reduction rate of up to 36 %. In addition, as the soil layer increased by 5 m, the reduction rate decreased by 4 %, and when the ground condition at the tip of the micropile was weathered rock, the reduction rate increased by 14 % compared with that of weathered soil.

• Journal of the Korean Society of Marine Environment & Safety
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• v.28 no.2
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• pp.385-393
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• 2022

Hydrogen has reduced greenhouse gas (GHG) emissions, the main cause of global warming, and is emerging as an eco-friendly energy source for ships. Hydrogen is a substance with a lower flammability limit (LFL) of 4 to 75% and a high risk of explosion. To be used for ships, it must be sufficiently safe against leaks. In this study, we analyzed the effect of changes in the area of the air inlet / vent port on the ventilation performance when hydrogen leaks occur in the hydrogen tank storage room. The area of the air inlet / vent port is 1A = 740 mm × 740 mm, and the size and position can be easily changed on the surface of the storage chamber. Using ANSYS CFX ver 18.1, which is a CFD commercial software, the area of the air inlet / vent port was changed to 1A, 2A, 3A, and 5A, and the hydrogen mole fraction in the storage chamber when the area changed was analyzed. Consequently, the increase in the area of the air inlet port further reduced the concentration of the leaked hydrogen as compared with that of the vent port, and improved the ventilation performance of at least 2A or more from the single air inlet port. As the area of the air inlet port increased, hydrogen was uniformly stratified at the upper part of the storage chamber, but was out of the LFL range. However, simply increasing the area of the vent port inadequately affected the ventilation performance.

• KIPS Transactions on Software and Data Engineering
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• v.11 no.8
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• pp.339-346
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• 2022

Recently, the resource depletion and climate change problem caused by the massive usage of fossil fuels for electric power generation has become a critical issue worldwide. According to this issue, interest in renewable energy resources that can replace fossil fuels is increasing. Especially, photovoltaic power has gaining much attention because there is no risk of resource exhaustion compared to other energy resources and there are low restrictions on installation of photovoltaic system. In order to use the power generated by the photovoltaic system efficiently, a more accurate photovoltaic power forecasting model is required. So far, even though many machine learning and deep learning-based photovoltaic power forecasting models have been proposed, they showed limited success in terms of interpretability. Deep learning-based forecasting models have the disadvantage of being difficult to explain how the forecasting results are derived. To solve this problem, many studies are being conducted on explainable artificial intelligence technique. The reliability of the model can be secured if it is possible to interpret how the model derives the results. Also, the model can be improved to increase the forecasting accuracy based on the analysis results. Therefore, in this paper, we propose an explainable photovoltaic power forecasting scheme based on BiLSTM (Bidirectional Long Short-Term Memory) and SHAP (SHapley Additive exPlanations).

• Explosives and Blasting
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• v.40 no.4
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• pp.15-26
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• 2022

With the recent increase in old and dangerous buildings, the demand for technology in the field of structure demolition is rapidly increasing. In particular, in the case of structures with severe deformation of damage, there is a risk of deterioration in stability and disaster due to changes in the load distribution characteristics in the structure, so rapid structure demolition technology that can be efficiently dismantled in a short period of time is drawing attention. However, structural deformation such as unauthorized extension or illegal remodeling occurs frequently in many old structures, which is not reflected in structural information such as building drawings, and acts as an obstacle in the demolition design process. In this study, as an effective way to overcome the discrepancy between the structural information of old structures and the actual structure, access to actual structures through 3D modeling was considered. 3D point cloud data inside and outside the building were obtained through LiDAR and drone photography for buildings scheduled to be blasting demolition, and precision matching between the two spatial data groups was performed using an open-source based spatial information construction system. The 3D structure model was completed by importing point cloud data matched with 3D modeling software to create structural drawings for each layer and forming each member along the structure slab, pillar, beam, and ceiling boundary. In addition, the modeling technique proposed in this study was verified by comparing it with the actual measurement value for selected structure member.

• Journal of Korea Entertainment Industry Association
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• v.13 no.1
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• pp.25-34
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• 2019

The purpose of this study is to develop a mobile app for mental health self care of university student. User centered design is a research design that applies the subject's needs assessment, analysis, design, development, evaluation, modification and supplement to suit the subjects. In order to manage the mental health of university students, they consisted of four main areas of mental health problems: drinking, sleeping, depression, and stress. It is designed to enable self test content, analysis and notification of inspection results, and management plan for current status of each area. Based on this, I developed an Android based mental health self-care Application. The subject can enter his or her mental health status data to explain the normal or risk level for each result, and the subject can then select the appropriate intervention method that he or she can perform. In addition, we developed a mental health self care calendar that can display the present status of each of the four areas on a day by day basis, and the current status can be expressed in an integrated manner through animations and status bars. The purpose of this study was to develop a mental health self-care app that can be improved by continuous and improved programs.

• The Journal of Internal Korean Medicine
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• v.43 no.6
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• pp.1045-1062
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• 2022

Objectives: The aim of this study was to analyze the latest clinical studies on Korean medicine treatment of idiopathic thrombocytopenic purpura (ITP) in the Chinese National Knowledge Infrastructure (CNKI) database. Methods: We searched the last 6 years of clinical studies discussing Oriental medicine-based treatments for ITP in the CNKI database. A meta-analysis of 13 RCTs was performed by synthesizing the outcomes, including the measured platelet count and total effective rate. The quality of the studies was assessed using Cochrane's risk of bias (RoB) tool. RevMan 5.4.1 software was used for data analysis. Results: Of the 15 selected studies, 1 was a non-randomized controlled trial (nRCT), 2 were case series, and 12 were randomized controlled trials (RCTs). Treatments in all studies included oral herbal medicine. The most frequently used herbal decoction was the Liangxue Jiedu prescription (凉血解毒方), and the most commonly used herb was Agrimonia pilosa (仙鶴草), Astragali Radix (黃芪), Fossilia Glycyrrhizae Radix et Rhizoma (甘草), and Rehmannia glutinosa Liboschitz ex Steudel (地黃). The meta-analysis showed significantly better improvement in platelet counts and total effective rate for ITP in the treatment group than in the control group. Conclusion: Treatment with herbal medicine was effective in treating ITP. However, the significance of this conclusion is somewhat limited due to the low quality of the available studies. Multifaceted and scientifically designed clinical studies are required to develop treatments for ITP based on Korean medicine. The results of this study could be used as basic data for further ITP studies.

• Therapeutic Science for Rehabilitation
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• v.12 no.2
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• pp.55-68
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• 2023

Objective : This study aims to analyze the effects of visual perception intervention by systematically reviewing the studies that applied visual perception intervention to children with cerebral palsy. Methods : The databases used were PubMed, EMbase, Science Direct, ProQuest, Koreanstudies Information Service System (KISS), Research Information Sharing Service (RISS), and the National Assembly Library. The keywords used were cerebral palsy, CP, and visual perception. According to the PRISMA flowchart, 10 studies were selected from among studies published from January 1, 2012 to March 30, 2022. The quality level of the selected studies, the demographic characteristics of study participants, the effectiveness of interventions, area and strategies of intervention, assessment tools to measure the effectiveness of interventions, and risk of bias were analyzed. Results : All selected studies confirmed that visual perception intervention was effective in improving visual perception function. In addition, positive results were shown in upper extremity function, activities of daily living, posture control, goal achievement, and psychosocial areas as well as visual perception function. The eye-hand coordination area was intervened in all studies. Conclusion : In visual perception intervention, It is necessary to evaluate the visual perception function by area, and apply systematically graded customized interventions for each individual.