• Restorative Dentistry and Endodontics
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• 제44권1호
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• pp.5.1-5.9
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• 2019

Objectives: The aim of this in vitro study was to evaluate the push-out bond strength of a novel calcium silicate-based root repair material-BIOfactor MTA to root canal dentin in comparison with white MTA-Angelus (Angelus) and Biodentine (Septodont). Materials and Methods: The coronal parts of 12 central incisors were removed and the roots were embedded in acrylic resin blocks. Midroot dentin of each sample was horizontally sectioned into 1.1 mm slices and 3 slices were obtained from each root. Three canal-like standardized holes having 1 mm in diameter were created parallel to the root canal on each dentin slice with a diamond bur. The holes were filled with MTA-Angelus, Biodentine, or BIOfactor MTA. Wet gauze was placed over the specimens and samples were stored in an incubator at $37^{\circ}C$ for 7 days to allow complete setting. Then samples were subjected to the push-out test method using a universal test machine with the loading speed of 1 mm/min. Data was statistically analyzed using Friedman test and post hoc Wilcoxon signed rank test with Bonferroni correction. Results: There were no significant differences among the push-out bond strength values of MTA-Angelus, Biodentine, and BIOfactor MTA (p > 0.017). Most of the specimens exhibited cohesive failure in all groups, with the highest rate found in Biodentine group. Conclusions: Based on the results of this study, MTA-Angelus, Biodentine, and BIOfactor MTA showed similar resistances to the push-out testing.

• 한국융합학회논문지
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• 제10권5호
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• pp.35-42
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• 2019

최근 사물인터넷과 다양한 웨어러블 기기들이 등장하면서 인터넷 기술은 보다 편리하게 정보를 얻고 업무를 수행하는데 기여하고 있으나 인터넷이 다양한 부분에 이용되면서 공격에 노출되는 Attack Surface 지점이 증가하고 있으며 개인정보 획득, 위조, 사이버 테러 등 부당한 이익을 취하기 위한 목적의 네트워크 침입 시도 또한 증가하고 있다. 본 논문에서는 네트워크에서 발생하는 트래픽에서 비정상적인 행동을 분류하기 위한 희소클래스의 분류 성능을 개선하는 특징선택을 제안한다. UNSW-NB15 데이터셋은 다른 클래스에 비해 상대적으로 적은 인스턴스를 가지는 희소클래스 불균형 문제가 발생하며 이를 제거하기 위해 언더샘플링 방법을 사용한다. 학습 알고리즘으로 SVM, k-NN 및 decision tree를 사용하고 훈련과 검증을 통하여 탐지 정확도와 RMSE가 우수한 조합의 서브셋들을 추출한다. 서브셋들은 래퍼 기반의 실험을 통해 재현률 98%이상의 유효성을 입증하였으며 DT_PSO 방법이 가장 우수한 성능을 보였다.

• 교육녹색환경연구
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• 제18권1호
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• pp.38-48
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• 2019

본 연구는 대학 연구실 사고 예방을 위해서 실험 전 이루어지는 형식적인 일상점검을 보다 실효성 있는 일상점검표를 제시하는데 목적이 있다. 이를 위해 현재 실시중인 일상점검표와 선행연구자료를 재구성하여, 이를 토대로 2차에 걸친 전문가 델파이 조사로 연구를 실시하였다. 그 결과 연구실 정리정돈 등 일반안전 4개, 기계 및 공구 조임부 이상여부 등 기계기구안전 3개, 전기분전반 주변 적재금지 등 전기안전 3개, 유해인자취급 및 관리대장 비치 등 화공안전 6개, 소화기 점검 등 소방안전 3개, 가스용기 점점 등 가스안전 5개, 손 소독기 관리상태 등 생물안전 1개, 기타 1개, 총 26개 항목을 일상점검표로 제시하였다. 관련 전문가들의 의견을 종합해 보면, 실질적인 일상점검을 위해서는 쉽고 간소화 된 일상점검표가 필요한 것으로 나타났다.

• 농업과학연구
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• 제47권4호
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• pp.717-726
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• 2020

The physical characteristics of the major varieties of perilla were analyzed to use as basic data for the design of a high-quality, high-efficiency perilla cleaner and stone separator. Because the size, thousand-grain weight, angle of repose, angle of friction, bulk density and terminal velocity of perilla have significant differences according to the perilla variety, the different of characteristics by variety should be considered for performance improvement of a perilla cleaner and stone separator. Therefore the cleaner and stone separator using a sieve could be improved by the application of a detachable sieve or by using equipment such as a 2 - 3 stage sieve and regulating the slope. Moreover, because differences in the terminal velocity occur due to the differences in the size and thousand-grain weight according to the perilla variety, a blower with an adjustable fan speed was considered for the design of the improved cleaner. Additionally, it was shown that the length of perilla has the greatest correlation based on a comparison of the coefficients of the other characteristics. Accordingly, the length of perilla could be used as a major factor for the fine adjustment and parts replacement of the device. These results can be used as basic data for a high-quality, high-efficiency perilla cleaner and stone separator. In the future, the development of the machine and follow-up studies based on the basic data are needed to determine the optimized operating conditions and mechanism of action.

• 한국컴퓨터정보학회논문지
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• 제26권2호
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• pp.1-9
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• 2021

본문에서는 순수 함수형 언어인 하스켈로 작성된 심볼릭 실행의 병렬화를 위한 상태 모나드 기반의 라이브러리에 결정적 병렬화를 적용하기 편리한 API를 설계/구현하고 멀티코어 컴퓨터에서 벤치마크를 통해 실제 성능을 향상을 확인해 본다. 일반적으로 순수 함수형 프로그램은 병렬화가 쉽다고 알려져 있으나 실제 구현에서 핵심 알고리듬 외적인 부분에서 의도치 않은 순차적 데이터 의존성의 발생으로 병렬화가 어려워질 수 있다. 심볼릭 실행 구현에서는 지금껏 사용했던 변수와 겹치지 않는 새 이름을 생성함으로써 서로 다른 범위의 이름이 같은 변수끼리 혼동하는 착오를 피하는 방식을 종종 활용한다. 그런데 이를 순차적 상태 관리로 구현한 경우가 많아 병렬화에 걸림돌이 된다. 이 논문에서는 하스켈의 범용적 이름 관리 라이브러리인 unbound-generics의 새 이름 생성 기능에 순차적 의존성을 회피할 수 있는 확장 기능을 제공함으로써 병렬적 심볼릭 실행 구현을 간소화하는 데 기여하였다. 우리가 구현한 병렬화 확장의 특징은 기존 unbound-generics 라이브러리의 내부 구현을 그대로 유지한 상태의 확장이라는 점으로, 기존에 unbound-generics로 작성된 순차적 심볼릭 실행기의 성능 저하 우려가 전혀 없다는 점이다. 따라서 병렬화가 필요한 부분에만 확장 기능을 적용하는 방식으로 활용하여 성능을 개선할 수 있다.

• International Journal of Computer Science & Network Security
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• 제22권10호
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• pp.257-261
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• 2022

Diseases of agricultural plants in recent years have spread greatly across the regions of the Kyrgyz Republic and pose a serious threat to the yield of many crops. The consequences of it can greatly affect the food security for an entire country. Due to force majeure, abnormal cases in climatic conditions, the annual incomes of many farmers and agricultural producers can be destroyed locally. Along with this, the rapid detection of plant diseases also remains difficult in many parts of the regions due to the lack of necessary infrastructure. In this case, it is possible to pave the way for the diagnosis of diseases with the help of the latest achievements due to the possibilities of feedback from the farmer - developer in the formation and updating of the database of sick and healthy plants with the help of advances in computer vision, developing on the basis of machine and deep learning. Currently, model training is increasingly used already on publicly available datasets, i.e. it has become popular to build new models already on trained models. The latter is called as transfer training and is developing very quickly. Using a publicly available data set from PlantVillage, which consists of 54,306 or NewPlantVillage with a data volumed with 87,356 images of sick and healthy plant leaves collected under controlled conditions, it is possible to build a deep convolutional neural network to identify 14 types of crops and 26 diseases. At the same time, the trained model can achieve an accuracy of more than 99% on a specially selected test set.

• 소성∙가공
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• 제31권1호
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• pp.17-22
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• 2022

Hot stamping is widely used to manufacture structural parts to satisfy requirements of eco-friendly vehicles. Recently, hot forming technology using uncoated steel sheet is being studied to reduce cost and solve patent problems. In particular, research is focused on process technology capable of suppressing the generation of an oxide layer. To evaluate the oxide layer in the hot stamping process, Gleeble testing machine can be used to evaluate the oxide layer by controlling the temperature history and the atmosphere condition. At this time, since cooling by gas injection is impossible to protect the oxide layer on the surface of a specimen, research on a method for securing a quenching speed through natural cooling is required. This paper proposes a specimen shape design method to secure a target quenching speed through natural cooling when evaluating the oxide layer of an un-coated boron steel sheet by Gleeble test. For the evaluation of the oxide layer of the un-coated steel sheet through the Gleeble test, dog-bone and rectangular type specimens were used. In consideration of the hot stamping process, the temperature control conditions for the Gleeble test were set and the quenching speed according to the specimen shape design was measured. Finally, the quenching speed sensitivity according to shape parameter was analyzed through regression analysis. A quenching speed prediction equation was then constructed according to the shape of the specimen. The constructed quenching speed prediction equation can be used as a specimen design guideline to secure a target quenching speed when evaluating the oxide layer of an un-coated boron steel sheet by the Gleeble test.

• 한국산업융합학회 논문집
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• 제25권6_2호
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• pp.1111-1117
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• 2022

Recently, interest in the circular economy has emerged in the industry. As a result, interest in Re-manufacturing, which makes old equipment similar to new products, is growing. In the machine tool industry with many aging equipment, the Re-manufacturing industry is essential, and among them, research on the performance improvement of gear type oil pumps was conducted. The purpose was to achieve the target performance of flow rate and volume efficiency by changing the shape of the gear pump housing clearance and inlet/outlet, and Computational Fluid Analysis and Central Composite Design were conducted using ANSYS CFX 2022 R2 and MINITAB®. The level of each determined factor was determined. 20 design points were derived, and the Flow Rate at each design point was calculated, and the Theoretical Flow Rate was calculated to obtain Volumetric Efficiency. The optimal design point was obtained when the Flow Rate was 140 lpm and the Volumetric Efficiency was maximum, the optimal design point was obtained when both were maximum, and the Surface Plot for each factor was obtained to identify the tendency.

• 한국컴퓨터정보학회논문지
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• 제27권11호
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• pp.107-114
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• 2022

본 논문은 자율주행 학습이 가능한 택배 로봇을 제안한다. 제안하는 로봇은 지상 주차시설이 없는 공원형 아파트에서 활용 가능하도록 설계되었으며 지상 및 지하 경로가 복잡한 기존 아파트에 비해 공원형 아파트는 이동 경로가 정형화되어 있어 로봇의 안정적인 주행이 가능하여 학생들의 초기 교육 환경으로 적합하다. 택배 로봇은 경로학습을 위한 머신러닝 기술과 카메라와 라이다 센서를 이용한 자율주행을 통하여 택배 운반이 가능하도록 구성하였다. 또한, 수준별 학습이 가능하도록 제어 MCU를 3개로 분리하여 설계하였으며 자율주행, 장애물 인식 등의 동작 테스트를 통하여 학습용 택배 로봇으로 활용될 수 있음을 확인하였다. 향후 정밀한 실내 위치정보 인식 기술과 아파트의 공공기술 플랫폼과 연동하여 다양한 배송 서비스를 위한 교육용 배송 로봇으로 발전시키고자 한다.

• 대한치위생과학회지
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• 제5권1호
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• pp.13-19
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• 2022

Background: In this study, zirconia copings were fabricated by setting clinically acceptable inner values for prostheses using computer-aided design/computer-aided manufacturing (CAD/CAM). The processed copings were evaluated for the marginal and internal fit of each abutment shape with a CAD program using the silicone replica technique. Methods A total of 20 copings was produced by selecting models commonly used in clinical practice. After injecting the sample, the minimum thickness, internal adhesion interval, and distance to the margin line were set to 0.5, 0.05, and 1.00 mm using a dental CAD program, respectively. It was measured using a 2D section function in a three-way program of the silicon replication technology. Although the positions and number of measurements of the anterior and posterior regions differed, nine parts of each pre-tube were designated and measured by referring to a previous study to compare the two samples. Results As a result, the average margin of the mesial, distal, and buccal (labial) surfaces was 59.90 ㎛ in the anterior region and 60.40 ㎛ in the posterior region. The mean axial wall margin was 67.25 ㎛ in the anterior region and 69.25 ㎛ in the posterior region. In occlusion, the anterior teeth (77.70 ㎛), posterior teeth (77.60 ㎛), and both anterior and posterior regions were within the clinically acceptable range. Conclusion The edge and inner fit of zirconia coping manufactured using the CAD/CAM system showed clinically applicable results. To reduce errors and increase accuracy, materials and machine errors that affect the manufacture of prosthetics should be investigated. Based on our results, the completeness of prosthetics could increase if the inner value and characteristics of the material are adjusted when applied in clinical practice.