• Proceedings of the Korea Information Processing Society Conference
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• 2017.11a
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• pp.1307-1310
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• 2017

이 논문에서는 다종 재배 환경을 고려한 이동형 스마트팜 모니터링 로봇을 제안한다. 기존 스마트 농장 연구는 각 구역마다 고정형 측정 장치를 이용하여 데이터를 수집한다. 또한 고정형 센서 기반 스마트 농장이므로 다종, 다수의 센서가 필요하다는 문제점이 있다. 이 논문에서 제안하는 것은 기존의 스마트 농장과는 달리 스마트팜 모니터링 로봇은 농장의 모든 구역을 이동을 하며 데이터를 측정, 수집한다. 그리고 수집한 데이터를 웹 페이지를 통해 시각화한다. 그 결과 제안한 시스템을 통해 자동으로 이동 및 측정을 하여 다종의 재배 환경에서도 안정적으로 정확한 측정이 가능하다는 장점이 있다.

• Journal of the Korean Ceramic Society
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• v.50 no.6
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• pp.466-469
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• 2013

Currently, piezoelectric ceramics are being applied in various fields, such as ultrasonic sensors, vibration devices, sound filters, and various energy conversion devices. Flexible piezoelectric ceramics are widely studied in an effort to mitigate the disadvantages of their brittle and inductile properties. Structural damage to piezoelectric fibers is much less than that to thin films when piezoelectric fibers are twisted or bent. Therefore, stretchable devices can be fabricated if piezoelectric fibers are obtained using an elongated substrate. In this study, sintering processes of PZT ($Pb(Zr_{0.53}Ti_{0.47})O_3$) fibers prepared by electrospinning were optimized through the TGA and XRD analyses. The crystal structure and microstructure of the piezoelectric fibers were investigated by XRD, FE-SEM and TEM.

• Nuclear Engineering and Technology
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• v.53 no.8
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• pp.2646-2651
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• 2021

A rectangular-shaped PET system with an adjustable gantry (AGPET) has been developed for imaging small animals. The AGPET system employs a new depth of interaction (DOI) method using a depth dependent reflector patterns and a new digital time pickoff method based on the pulse reconstruction method. To evaluate the performance of the AGPET, timing resolution, intrinsic spatial resolution and point source images were acquired. The timing resolution and intrinsic spatial resolution were measured using two detector modules and Na-22 gamma source. The PET images were acquired in two field of view (FOV) sizes, 30 mm and 90 mm, to demonstrate the characteristic of the AGPET. As a result of in the experiment results, the timing resolution was 0.9 ns using the pulse reconstruction method based on the bi-exponential model. The intrinsic spatial resolution was an average of 1.7 mm and the spatial resolution of PET images after DOI correction was 2.08 mm and 2.25 mm at the centers of 30 mm and 90 mm FOV, respectively. The results show that the proposed AGPET system provided higher sensitivity and resolution for small animal imaging.

• Nuclear Engineering and Technology
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• v.55 no.3
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• pp.1009-1014
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• 2023

Muon tomography is a useful method for monitoring special nuclear materials (SNMs) such as spent nuclear fuel inside dry cask storage. Multiple Coulomb scattering of muons can be used to provide information about the 3-dimensional structure and atomic number(Z) of the inner materials. Tomography using muons is less affected by the shielding material and less harmful to health than other measurement methods. We developed a muon detector for muon tomography, which consists of a plastic scintillator, 64 long wavelength-shifting (WLS) fibers attached to the top of the plastic scintillator, and silicon photomultipliers (SiPMs) connected to both ends of each WLS fiber. The muon detector can acquire X and Y positions simultaneously using a position determination algorithm. The design parameters of the muon detector were optimized using DETECT2000 and Geant4 simulations, and a muon detector prototype was built based on the results. Spatial resolution measurement was performed using simulations and experiments to evaluate the feasibility of the muon detector. The experimental results were in good agreement with the simulation results. The muon detector has been confirmed for use in a muon tomography system.

• Proceedings of the Korean Society of Computer Information Conference
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• 2022.07a
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• pp.225-228
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• 2022

본 논문에서는 의미적 유사도 기반의 장면 분할 방법을 제안한다. 이 방법은 의미적 접근을 통해 기존 연구에서 가졌던 한계를 극복하고 정확한 장면 분할이 가능할 것으로 기대한다. 의미적 유사도 비교를 Class 종류 비교, Class별 객체의 개수 비교, 샷 간의 Histogram비교, 객체의 관심영역(ROI) Histogram비교 총 4가지 규칙으로 정의했고 이때 도출된 4가지 유사도는 전처리를 거쳐 종합 유사도를 계산한다. 또한 의미적 접근을 통해 연속되는 Shot의 유사도를 비교하고 기준값에 따라 Shot을 묶어서 최종적으로 의미적 유사도(Semantic Similarity)에 기반한 장면의 경계(Scene Boundary) 분할 방법을 제시한다.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.31 no.6
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• pp.392-397
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• 2018

In this paper, the ZnS nanoparticles were synthesized according to the process conditions of hydrothermal synthesis. When the molar ratio of Zn to S was 1:1.2, it was confirmed that it had a cubic single phase and a high crystal phase. After the molar ratio is fixed, hydrothermal synthesis was conducted at $180^{\circ}C$ for 24, 36, 72 and 96 h in order to confirm the structural change with the change of hydrothermal synthesis times. As the hydrothermal synthesis times increased, the particle size increased. The hydrothermal synthesized particle size for 72 h was considered to be suitable for sintering. The ZnS ceramic had a density of 99.7% and an excellent transmittance of ~70% in the long-wavelength region.

• Journal of The Korean Society of Agricultural Engineers
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• v.64 no.1
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• pp.15-26
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• 2022

3D open-field farm model developed from UAV (Unmanned Aerial Vehicle) data could make crop monitoring easier, also could be an important dataset for various fields like remote sensing or precision agriculture. It is essential to separate crops from the non-crop area because labeling in a manual way is extremely laborious and not appropriate for continuous monitoring. We, therefore, made a 3D open-field farm model based on UAV images and developed a crop segmentation model using a supervised machine learning algorithm. We compared performances from various models using different data features like color or geographic coordinates, and two supervised learning algorithms which are SVM (Support Vector Machine) and KNN (K-Nearest Neighbors). The best approach was trained with 2-dimensional data, ExGR (Excess of Green minus Excess of Red) and z coordinate value, using KNN algorithm, whose accuracy, precision, recall, F1 score was 97.85, 96.51, 88.54, 92.35% respectively. Also, we compared our model performance with similar previous work. Our approach showed slightly better accuracy, and it detected the actual crop better than the previous approach, while it also classified actual non-crop points (e.g. weeds) as crops.

• Journal of the Korean Data and Information Science Society
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• v.16 no.4
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• pp.1013-1015
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• 2005

Liu[Fuzzy Optimization and Decision Making, 2(2003), 87-100] proved that convergence in credibility does not imply convergence a.s. and convergence in mean does not imply convergence a.s. by giving counter-examples. But these examples are not true. In this note, we prove that convergence in credibility implies convergence a.s. and convergence in mean implies convergence a.s.

• Journal of the Korean Society of Visualization
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• v.15 no.2
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• pp.3-9
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• 2017

• Journal of the Korean Society of Visualization
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• v.17 no.3
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• pp.19-23
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• 2019

The purpose of this research is to develop a facile measurement system for colorimetric analysis for zinc powder and size analyzer for zeolite particles in order to reduce the process time for their characteristic analysis. We present facile smartphone-based analysis methods to measure and estimate the size of zinc power by using colorimeteric method and the size of zeolite particles by using ImageJ program which is an open-source program. The results show a possibility of our methods to replace the previous professional analysis processes with them.