• The Journal of Engineering Geology
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• v.28 no.4
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• pp.701-714
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• 2018

The purpose of this study is to show the possibility of 3-dimensional modeling of open-pit limestone mine by using a rotary-wing unmanned aerial vehicle, a drone, and to estimate the amount of mining before and after mining of limestone by explosive blasting. Analysis of the image duplication of the mine has shown that it is possible to achieve high image quality. Analysis of each axis error at the shooting position after analyzing the distortions through camera calibration was shown the allowable range. As a result of estimating the amount of mining before and after explosive blasting, it was possible to estimate the amount of mining of a wide range quickly and accurately in a relatively short time. In conclusion, it is considered that the drone of a rotary-wing unmanned aerial vehicle can be usefully used for the monitoring of open-pit limestone mines and the estimation of the amount of mining. Furthermore, it is expected that this method will be utilized for periodic monitoring of construction sites and road slopes as well as open-pit mines in the future.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.12
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• pp.451-461
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• 2018

This study investigated changes in the youth smoking rate and smoking cessation rates before and after a cigarette price increase in 2015. Specifically, the changes in smoking rate, smoking cessation attempt rate, selection rate and amount of smoking were investigated using primary data pertaining to Korean Youth Risk Behavior obtained from a web-based survey of youth general characteristics, mental health, subjective grade, drinking and smoking related characteristics before and after a cigarette price increase. To accomplish this, 800 middle school and high school students in 9th (2013), 10th (2014), 11th (2015) were surveyed. The current youth smoking rate was slightly decreased from 9.7% in 2013 to 9.2% in 2014, while the smoking rate in 2015 decreased significantly by 15.2% after the cigarette price increased to 7.8%. These results confirmed that increasing cigarette price is very effective at decreasing youth smoking rate, providing motivation to stop smoking and preventing smoking. The prevention of smoking and inducement to stop smoking during adolescence is very important because the majority of teenage smokers continue smoking into their adulthood. In addition to expanding a completely non-smoking area and a comprehensive ban on tobacco advertising, promotion and sponsorship should be urgently sought, and the effect can be maximized when the WHO FCTC faithfully implements the already-founded treaty.

• Journal of Dental Rehabilitation and Applied Science
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• v.36 no.4
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• pp.242-253
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• 2020

Purpose: The aim of this study was to compare the accuracy of dies fabricated using 3D printing system to conventional method and to evaluate overall volumetric changes by arranging the superimposed surfaces. Materials and Methods: A mandibular right first molar from a dental model was prepared, scanned and fabricated with composites of polyetherketoneketone (PEKK). Master dies were classified into 4 groups. For the conventional method, the impression was taken with polyvinylsiloxane and the impression was poured with Type IV dental stone. For the 3D printing, the standard die was scanned and converted into models using three different 3D printers. Each of four methods was used to make 10 specimens. Scanned files were superimposed with the standard die by using 3D surface matching software. For statistical analysis, Kruskal-Wallis test and Mann-Whitney U test were done (P < 0.05). Results: Compared to the standard model, the volumetric changes of dies fabricated by each method were significantly different except the models fabricated by conventional method and 3D printer of Stereolithography (P < 0.05). The conventional dies showed the lowest volumetric change than 3D printed dies (P < 0.05). 3D printed dies fabricated by Stereolithography showed the lowest volumetric change among the different 3D printers (P < 0.05). Conclusion: The conventional dies were more accurate than 3D printed dies, though 3D printed dies were within clinically acceptable range. Thus, 3D printed dies can be used for fabricating restorations.

• Food Science and Industry
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• v.55 no.1
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• pp.58-73
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• 2022

Due to the recent demand for low-calorie foods, consumers are looking for alternative sweeteners that can control blood sugar, low risk of tooth decay and low calories. Regulations for permitted sweeteners in food vary from every country, and it is important for the government and the food industry to monitor products containing these sweeteners to ensure global compliance. Therefore, rapid, precise, and accurate analysis for food matrices should be applied to quality control, market surveillance, monitoring, and evaluation of food additive intake in the food industry. To analyze sweeteners simultaneously, it is essential to develop an efficient and rapid analytical method and to perform appropriate pretreatment steps such as solvent extraction and purification. This study presented the recent analysis trends about the suitable extraction method for food matrices focusing on non-nutritive sweeteners. Additionally, techniques for multi-compounds analysis using HPLC and LC-MS/MS and non-destructive analysis techniques using FT-IR were comprehensively described.

• Journal of the Korean Geotechnical Society
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• v.38 no.12
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• pp.67-78
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• 2022

In this study, the measurement results of the coastal deep soft ground buried in the upper part of the dredged clay were analyzed and compared with the current specification standards. Based on the results, a suitable proposal was suggested for the selection, installation, data arrangement, and analysis of each instrument used in the deep soft ground improvement construction. The pore water pressure meter has a range of 1.5 times or more of the expected measurement range, considering the field conditions of the soft ground. The groundwater level meter installed in the horizontal drainage layer checks the change in the groundwater level during the embanking as well as the performance of the catchment well and the horizontal drainage layer. Therefore, it is important to manage so that the groundwater level exists inside the horizontal drainage layer during embanking. It is enough to install the inclinometer in the gravel layer below the soft ground or weathered rock with an N value of 40 or more for the deep soft ground. It seems desirable to install a screw type for differential settlement meter. However, the screw type should not settle due to its own weight. Considering that it is a dredged landfill where subsidence occurs significantly, it is sufficient to manage the tolerance of leveling at about 10 mm (L is the one-way distance (km)).

• Journal of Digital Convergence
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• v.20 no.2
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• pp.325-338
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• 2022

This study was conducted to explore the acceptance behavior of undergraduate students toward telemedicine, which is temporarily allowed in the COVID-19. We applied social cognitive theory and technology acceptance model in order to reflect the convergence characteristics between medical service and digital technology of telemedicine. Based on these theoretical backgrounds, we investigated perception toward telemedicine and determinants of intention to accept telemedicine. To examine the research model and hypothesis, an online survey was conducted for college students who have not used telemedicine from September 8 to 10, 2021. A total of 184 data were collected, and multiple regression analysis was conducted using the SPSS 28.0 program. The results showed that health technology self-efficacy, usefulness and convenience benefits, social norm, and trust in telemedicine providers had positive effects on intention to accept telemedicine. This study is meaningful in that it selected undergraduate students, who are digital natives, as new targets for telemedicine, and presented the basic direction of strategies to target them.

• Proceedings of the Korea Water Resources Association Conference
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• 2023.05a
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• pp.297-297
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• 2023

최근 친수성, 경관, 생태계 보전 등을 위해 다양한 호안블록의 시공이 이루어지고 있어 호안블록의 수리적 안정성에 관한 관심이 증가하고 있다. 이러한 배경 하에 한국건설기술연구원 안동하천실험센터(이하 센터)에서는 2019년부터 실규모 수로를 이용하여 여러 건의 호안블록 실규모 수리검토 실험을 실시한 바 있다. 본 연구는 그간의 실험 결과를 종합적으로 고찰하고 수리 검토 실험의 현황과 한계점, 그리고 개선 방향을 제언하는데 그 목적이 있다. A1 수로(급경사수로, 하상경사 1/70)에서는 7건(21회), B1 수로(고유속수로, 하상경사 1/7)에서는 2건(6회)의 실험이 수행되었다. A1 수로 실험의 유량-소류력 관계는 1.0 m³/s에서 약 20 N/m²이며, 1.0 m³/s 증가당 약 11 N/m²이 증가하는 관계를 나타낸다. 7건의 실험 결과 30분 이상 지속된 최대 실험 유량은 6~7 m³/s 정도이며, 이는 A1 최대 공급 유량의 75 % 정도로서 안정적인 수준이라고 판단된다. 이 때의 최대 소류력은 75 N/m² 정도로 나타났다. B1 수로는 5 m/s 이상의 고유속 흐름을 발생시킬 수있으며, 2건의 실험 결과 0.5 m³/s에서 약 100 N/m², 최대 4.5 m³/s에서 330 N/m²까지 소류력을 제공하여 실험을 수행한 바 있다. 따라서 A1, B1 수로를 통해 제공할 수 있는 소류력 범위는 10~330 N/m²이지만, 75~100 N/m²는 실험에서 제공된 바 없었다. 한편, 토양유실의 경우 수준측량에 의해 측정되는데, 대부분의 실험에서 Clopper의 토양손실 지수(1.27 cm) 미만의 결과가 발생하였다. 이는 시험체에 따라 여건이 다르기는 하지만, 수리 검토 실험시 3회 실험을 기본으로 하고 있고 호안재료의 침식이 기준 이하로 유지되면서 최대한의 성능을 발휘할 수 있는 소류력 조건을 얻으려는 실험 목적에 부합하도록 조절된 것으로 볼 수 있다. 이러한 실험 결과를 토대로 고려해볼 수 있는 개선 방향은 다음과 같다. 강성 재료가 아닌 연성 또는 친환경적 호안재료의 허용 소류력 범위를 보다 넓게 평가하기 위해 A1 수로가 제공하는 최대 소류력을 높일 필요가 있다. 이를 위해 기본 3회의 실험 외에 추가로 호안블록이 파괴되거나 토양유실 임계치를 초과할 수 있는 실험을 수행함으로써 각 제품의 한계 성능을 평가하는 것이 필요할 것으로 보인다.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.50 no.4
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• pp.287-295
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• 2022

As low altitude long-range artillery threat has been strengthened, the development of anti-artillery interception system to protect assets against its attacks will be kicked off. We view the defense of long-range artillery attacks as a typical dynamic weapon target assignment (DWTA) problem. DWTA is a sequential decision process in which decision making under future uncertain attacks affects the subsequent decision processes and its results. These are typical characteristics of Markov decision process (MDP) model. We formulate the problem as a MDP model to examine the assignment policy for the defender. The proximity of the capital of South Korea to North Korea border limits the computation time for its solution to a few second. Within the allowed time interval, it is impossible to compute the exact optimal solution. We apply approximate dynamic programming (ADP) approach to check if ADP approach solve the MDP model within processing time limit. We employ Shoot-Shoot-Look policy as a baseline strategy and compare it with ADP approach for three scenarios. Simulation results show that ADP approach provide better solution than the baseline strategy.

• Korea Trade Review
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• v.43 no.4
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• pp.111-130
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• 2018

In December 2015, the Paris Agreement was adopted to cope with global warming caused by greenhouse gas emission and to prevent the average temperature of the Earth from rising. Renewable energy sources have become important to address environmental problems such as rising sea levels, depletion of forests and fine dust. In order to grow renewable energy, government support is needed. However, excessive government support for the renewable energy industry could pose problems that include undermining fair competition and raising costs. The WTO already has heard cases involving renewable energy subsidies. This article focuses on subsidies and countervailing tariffs as well as examines WTO disputes related to renewable subsidies, and also analyze legal issues that are problematic in granting subsidies for the development of new renewable energy industries. In WTO dispute involving renewable energy subsidies, legal issues are SCM Agreement article 2 Specificity, article 3 (b) import substitution subsidy and GATT article 20. This paper proposes improvement measures such as the reintroduction of article 8 Non-Actionable Subsidies or special provisions on energy subsidy. In addition, it is necessary to clarify the interpretation of Article 3 of the subsidy agreement. However, excessive government subsidies can lead to trade friction, so the WTO rules should be improved in line with the WTO goals of environmental protection, equity in free trade, and sustainable development.

• Journal of Intelligence and Information Systems
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• v.29 no.2
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• pp.23-34
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• 2023

Wearable technology for military applications has received considerable attention as a means of personal status check and monitoring. Among many, an implementation to recognize specific motion states of a human is promising in that allows active management of troops by immediately collecting the operational status and movement status of individual soldiers. In this study, as an extension of military wearable application research, a new ankle wearable device is proposed that can glean the information of a soldier on the battlefield on which action he/she takes in which environment. Presuming a virtual situation, the soldier's upper limbs are easily exposed to uncertainties about circumstances. Therefore, a sensing module is attached to the ankle of the soldier that may always interact with the ground. The obtained data comprises 3-axis accelerations and 3-axis rotational velocities, which cannot be interpreted by hand-made algorithms. In this study, to discern the behavioral characteristics of a human using these dynamic data, a data-driven model is introduced; four features extracted from sliced data (minimum, maximum, mean, and standard deviation) are utilized as an input of the model to learn and classify eight primary military movements (Sitting, Standing, Walking, Running, Ascending, Descending, Low Crawl, and High Crawl). As a result, the proposed device could recognize a movement status of a solider with 95.16% accuracy in an arbitrary test situation. This research is meaningful since an effective way of motion recognition has been introduced that can be furtherly extended to various military applications by incorporating wearable technology and artificial intelligence.