• Proceedings of the Korea Information Processing Society Conference
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• 2021.11a
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• pp.1071-1074
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• 2021

본 논문은 펌웨어와 인공지능을 이용하여 지형의 사각지대를 이동하며 순찰 및 방범의 목적을 지닌 시스템을 소개하기 위함에 있다. 기존의 보안 시스템은 비상 상황 발생 시 인력이 직접 출동하여 상황을 해결함으로써 날로 증가하는 최저임금을 고려했을 때 이들의 인건비를 감당하기 어렵다는 단점이 있다. [1] 이러한 문제점을 해결하기 위해 앱 개발을 통해 RC카를 제어하는 아두이노와 연결하여 자율주행을 하게끔 하는 시스템을 개발했다. 또한, 라즈베리파이 웹캠을 부착해 실시간으로 현장을 촬영하여 사용자가 웹에만 접속하면 현장을 모두 감시할 수 있도록 시스템을 개발하였고, 단시간 푸리에 변환(STFT)을 통해 얻은 음성 데이터 변환맵을 인공지능 프로세서인 인텔리노에 학습 데이터로 학습시킨 후에 주변 환경에서 비명 소리만 감지할 수 있도록 시스템을 구현하였다. 본 논문에서는 이러한 시스템들이 기존의 인건비 증가에 대한 문제점을 해소할 수 있다고 생각하여 더욱 효율적으로 방범이 가능한 시스템을 소개한다.

• Applied Chemistry for Engineering
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• v.28 no.3
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• pp.313-317
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• 2017

With the continuous increase of energy demand, low-grade coal is regarded as one of new energy sources. However, due to the high water content, the utilization efficiency of low-grade coal is not good to be used in recent conversion plants. Therefore, it requires a drying process to lower the water content in low-grade coals. Although a variety of drying experiments were conducted, drying characteristics in accordance with the pressure change has not been progressed. In this study, the flash drying characteristics of low grade coal with high moisture content (21.5 wt%) were determined in a pressurized micro-riser. The effect of operation conditions such as pressure (1-40 bar), dryer temperature ($200-600^{\circ}C$), and tube length (2-6 m) on drying ratios were investigated.

• Korean Chemical Engineering Research
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• v.56 no.5
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• pp.631-640
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• 2018

The application of an oxy-combustion circulating fluidized bed combustor (Oxy-CFBC) for low grade coals has recently developed in the world to meet the continuous increase of energy demand and to achieve the reduction of greenhouse gases. Since demo plants for Oxy-CFBC have been developed, the combustion properties of Oxy-CFBC in various operation conditions, such as gas flow rates, combustion temperature, fuel, and so on, should be investigated to develop design criteria for a commercial Oxy-CFBC. In this study, a computational simulation tool for Oxy-CFBC was developed on the basis of the IEA-CFBC (International Energy Agency Circulating Fluidized Bed Combustor) model. Simulation was performed under various conditions such as reaction temperature ($800^{\circ}C{\sim}900^{\circ}C$), oxygen contents (21%~41%), coal feeding rate, Ca/S mole ratio (1.5~4.0), and so on. Simulation results show that the combustion furnace temperature is higher in oxy 1 than air fired. However, the temperature gradient tended to decrease with increasing oxy mixing percent. In case of $SO_x$, the higher the Ca/S mole ratio and oxy mixing percent, the higher the desulfurization efficiency.

• Korean Chemical Engineering Research
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• v.56 no.6
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• pp.856-863
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• 2018

In order to investigate the re-carbonation behaviors of limestones in an oxy-circulating fluidized bed combustor (Oxy-CFBC), the re-carbonation characteristics of domestic 4 different limestone samples were analyzed in a thermogravimetric analyzer (TGA-N1000) with the higher concentration of $CO_2$. Effect of reaction temperature ($600{\sim}900^{\circ}C$) and $CaCO_3$ content (77~95%) of limestones were determined and the mass change of the CaO was observed. Under the temperature of $800^{\circ}C$, the conversion rate increased with increasing reaction temperature. However, the conversion rate decreased with increasing reaction temperature over $800^{\circ}C$. In the case of $CaCO_3$ content, the conversion was remarkably different at $870^{\circ}C$. In addition, reaction rate equations for simulating the re-carbonation of limestone by using gas solid reaction models were proposed in this study.

• Korean Chemical Engineering Research
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• v.57 no.5
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• pp.687-694
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• 2019

In order to investigate the behavior of limestones which have been usually used for in-situ desulfurization reaction in circulating fluidized bed combustors, the attrition characteristics and calcination reactions of domestic limestones were analyzed in this study by using a thermogravimetric analyzer and an ASTM D5757-95 attrition tester. The average size distribution of limestones in circulating fluidized bed boilers have to be changed due to the attrition of particle-particle and particle-reactor wall and the calcination reaction. Domestic limestones might be used in commercial circulating fluidized bed boilers, but the attrition behaviors and particle size changes of limestones were varied. In calcination experiments at $850^{\circ}C$, the calcination reaction were varied with limestone samples. The calcination reaction time increased with an increase of particle size. Also, fine particles generated the attrition test of calcined limestone was 20% higher than those generated the attrition test of original limestone.

• Journal of Korean Academy of Dental Administration
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• v.7 no.1
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• pp.21-28
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• 2019

The purpose of this study was to investigate the association between wrong postures and pain during scaling and encourage dental hygienists and students to exercise scaling in a good position. After obtaining informed consent, 107 students (3rd and 4th grade students) who had an experience with scaling practice were enrolled. The questionnaire included three general items, four items related to the posture during scaling, and nine items related to pain management (total 16 items), for which the five-point Likert scale was used. Through the questionnaire, we examined the preference of posture during scaling, posture education during scaling, pain in each part during scaling, pain management, and pain management method. In the scaling exercise, 86.3% of the subjects were instructed on the correct posture, and 87.9% of the subjects perceived the possibility of inducing musculoskeletal disorders based on the scaling posture. The percentage of subjects who responded that they performed scaling in the correct posture was 33.6% and that of subjects who answered that they bowed or turned their head by more than 15° was 64.4%. Further, 45.7% of the subjects answered that they bent their shoulders, and 29.9% of the subjects answered that their postures were not parallel to the floor. Pain during scaling was still higher when they bent their head, they bent their waist, and they bent their wrist (p<0.05). During scaling, pain was most frequent in the fingers and hands (15%), followed by the neck (14%), shoulders (11.2%), waist (9.3%), and feet and legs (2.8%). The percentage of subjects who performed regular exercise (or stretching) to prevent pain was 29.9% and that of subjects who managed pain after scaling was 12.1%. Further, exercise (24.6%) and self-massage (20.3%) were highly used as the pain management methods, and the school practice was preferred to education media for pain management (79.4%). In the scaling practice, there was a training on pain management, but the frequency of practicing in the wrong posture was high. Moreover, pain increased upon practicing in an incorrect posture. Therefore, more in-depth and systematic education on the necessity and method of musculoskeletal disease management during scaling is required.

• Journal of the Korean Society of Earth Science Education
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• v.14 no.2
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• pp.136-145
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• 2021

The Gifted Education Program is re-constructured into core competency-based program in line with fourth industrial revolution, where talented people with comprehensive ability are required. Therefore, competency-based elementary science gifted education program which is provided from Gifted Education Database(GED) is developed in accordance with 2015 revised edition in science and 5 main core-abilities; scientific thinking ability, scientific investigation ability, scientific problem solving ability, scientific communication ability and scientific participation and lifelong learning ability. This research, which is provided from GED, is focused on earth science area among competency-based elementary science gifted education program and analyse quantitatively and qualitatively how science and core-ability is appeared in 3 programs developed in science area. This research can be another guideline when someone would like to use competency-based earth science gifted education program in gifted education. Also, the purpose of this research is to help suggesting a right direction for competency-based earth science gifted education program. The conclusion based on research problem is as follow; Firstly, in competency-based earth science gifted education program, influence rates of scientific communication ability and scientific thinking ability are highest, where influence rates of scientific investigation ability, scientific problem solving ability and scientific participation and lifelong learning ability are relatively low. Secondly, in competency-based earth science gifted education program, single activity may includes several core-abilities. Following research is quite meaningful in aspect of giving out the information to choose topic in core-ability when using competency-based earth science gifted education program in gifted education. Also by supplementing lowly-influenced ability in competency-based earth science gifted education program, it is expected for gifted students to build scientific core-ability.