• Journal of the Korean Ceramic Society
• /
• v.51 no.6
• /
• pp.523-526
• /
• 2014

PZT($Pb(Zr_{0.53}Ti_{0.47})O_3$)/PVDF(poly vinylidene fluoride) nanofibers were prepared based on DMF (dimethylformamide) and acetone solvent by electrospinning. The optimum concentration of a PZT and PVDF composite solution for the formation of nanofibers was found by SEM (scanning electron microscopy) observations. XRD (X-ray diffraction) measurements indicated that the characteristics of PZT and PVDF coexisted. The effects of the PZT concentration on the tensile strength were investigated.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2011.10a
• /
• pp.659-661
• /
• 2011

In this paper, we propose a study of scheme to detect mobile object. In special zone needed detection, sensor network based system development can provide safety of pedestrian. Instead current CCTV, intelligent sensor network and service can provide reliability to guarantee safe zone. Base on pedestrian characteristic, if unusual situation is detected and it is included in previous agreed scenario, safety service can be provided.

• Journal of information and communication convergence engineering
• /
• v.17 no.1
• /
• pp.84-90
• /
• 2019

Applications of unmanned aerial vehicles (UAVs) in the military environment have become popular because they require minimum human contribution and can avoid accidents during missions. UAVs are employed in various missions such as reconnaissance, observation, aggression, and protection. Consequently, counter-measures, known as anti-drone technologies, have been developed as well. In order to protect against threats from anti-drone technologies and enhance the survivability of UAVs, this study proposes an evasive measure. The proposed bio-inspired evasive maneuver of a UAV mimics a dragonfly's irregular flight. The unpredictable UAV movement is able to confuse enemies and avoid threats, thereby enhancing the UAV's survivability. The proposed system has been implemented on a commercial UAV platform (AR Drone 2.0) and tested in a real environment. The experiment results demonstrate that the proposed flight pattern has larger displacement values compared to a regular flight maneuver, thus making the UAV's position is difficult to predict.

• Nuclear Engineering and Technology
• /
• v.54 no.2
• /
• pp.601-607
• /
• 2022

In recent years, monitoring of spent nuclear fuel inside dry cask storage has become an important area of national security. Muon tomography is a useful method for monitoring spent nuclear fuel because it uses high energy muons that penetrate deep into the target material and provides a 3-D structure of the inner materials. We designed a muon tomography system consisting of four 2-D position sensitive detector and characterized and optimized the system parameters. Each detector, measuring 200 × 200 cm², consists of a plastic scintillator, wavelength shifting (WLS) fibers and, SiPMs. The reconstructed image is obtained by extracting the intersection of the incoming and outgoing muon tracks using a Point-of-Closest-Approach (PoCA) algorithm. The Geant4 simulation was used to evaluate the performance of the muon tomography system and to optimize the design parameters including the pixel size of the muon detector, the field of view (FOV), and the distance between detectors. Based on the optimized design parameters, the spent fuel assemblies were modeled and the line profile was analyzed to conduct a feasibility study. Line profile analysis confirmed that muon tomography system can monitor nuclear spent fuel in dry storage container.

• Nuclear Engineering and Technology
• /
• v.54 no.6
• /
• pp.1982-1990
• /
• 2022

The purpose of this study was to verify the possibility of fuel rod pattern analysis in a fresh fuel assembly using the Yonsei single-photon emission computed tomography (YSECT) system. The YSECT system consisted of three main parts: four trapezoidal-shaped bismuth germanate scintillator-based 64-channel detectors, a semiconductor-based multi-channel data acquisition system, and a rotary stage. In order to assess the performance of the prototype YSECT, tomographic images were obtained for three representative fuel rod patterns in the 6 × 6 array using two representative image-reconstruction algorithms. The fuel-rod patterns were then assessed using an in-house fuel rod pattern analysis algorithm. In the experimental results, the single-directional projection images for those three fuel-rod patterns well discriminated each fuel-rod location, showing a Gaussian-peak-shaped projection for a single 10 mm-diameter fuel rod with 12.1 mm full-width at half maximum. Finally, we successfully verified the possibility of the fuel rod pattern analysis for all three patterns of fresh fuel rods with the tomographic images obtained by the rotational YSECT system.

• Nuclear Engineering and Technology
• /
• v.54 no.10
• /
• pp.3943-3948
• /
• 2022

Single-photon emission computed tomography is one of the reliable pin-by-pin verification techniques for spent-fuel assemblies. One of the challenges with this technique is to increase the total fuel assembly verification speed while maintaining high verification accuracy. The aim of the present study, therefore, was to develop an artificial intelligence (AI) algorithm-based tomographic image analysis technique for partial-defect verification of fuel assemblies. With the Monte Carlo (MC) simulation technique, a tomographic image dataset consisting of 511 fuel-rod patterns of a 3 × 3 fuel assembly was generated, and with these images, the VGG16, GoogLeNet, and ResNet models were trained. According to an evaluation of these models for different training dataset sizes, the ResNet model showed 100% pattern estimation accuracy. And, based on the different tomographic image qualities, all of the models showed almost 100% pattern estimation accuracy, even for low-quality images with unrecognizable fuel patterns. This study verified that an AI model can be effectively employed for accurate and fast partial-defect verification of fuel assemblies.

• Journal of the Korean Society of Industry Convergence
• /
• v.25 no.5
• /
• pp.783-789
• /
• 2022

In this study, STS316L rolled at five rolling degrees were treated with two types of subzero temperatures for 10, 30, and 60 minutes, respectively, and the dominant frequencies of elastic waves was investigated. The dominant frequency was higher as the subzero temperature was lower and the subzero treatment time was longer at each rolling degree. On the other hand, the dominant frequency was higher as the elongation decreased. In the time-frequency analysis for subzero temperature and time of the specimen with a rolling degree of 33%, the dominant frequency was higher at a subzero temperature of -196℃ than -50℃ regardless of subzero treatment time.

• Journal of information and communication convergence engineering
• /
• v.21 no.1
• /
• pp.75-81
• /
• 2023

Video platforms, including YouTube, have a structure in which the number of video views is directly related to the publisher's profits. Therefore, video publishers induce viewers by using provocative titles and thumbnails to garner more views. The conventional technique used to limit such harmful videos has low detection accuracy and relies on follow-up measures based on user reports. To address these problems, this study proposes a technique to improve the accuracy of filtering harmful media using thumbnails, titles, and audio data from videos. This study analyzed these three pieces of multimodal information; if the number of harmful determinations was greater than the set threshold, the video was deemed to be harmful, and its upload was restricted. The experimental results showed that the proposed multimodal information extraction technique used for harmfulvideo filtering achieved a 9% better performance than YouTube's Restricted Mode with regard to detection accuracy and a 41% better performance than the YouTube automation system.

• Proceedings of the Korean Society of Computer Information Conference
• /
• 2022.07a
• /
• pp.285-288
• /
• 2022

최근 코로나 확진자가 감소함에 따라 집합금지 명령이 해제되고 단계적 일상 회복이 진행되고 있다. 이에 맞춰 온라인 수업을 진행하던 학교들이 대면 수업으로 전환됨에 따라 학생들이 학교로 돌아오게 되었다. 하지만 학교에 처음 온 학생들은 학교 주변 상권에 대해 잘 모르는 경향이 있다. 본 논문에서는 이러한 학생들의 고민을 줄여주기 위하여 카테고리별로 맞춤 식당을 추천해주는 서비스 개발하였다. Kotlin을 활용한 안드로이드 애플리케이션 형태로 개발하였으며, 네이버 지도를 활용하여 식당의 위치를 알려주도록 하였다. 또한 Firebase를 활용한 게시판을 통해 소통의 창구를 마련하고 간단한 게임 등을 통해 학우들 간의 친밀도를 높일 수 있는 콘텐츠를 제공하였다.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.25 no.8
• /
• pp.657-663
• /
• 2012

The spherical mesoporous silica is synthesized and incorporated with CdSe/ZnS quantum dots(QDs) for preparing micro beads to detect toxic and bio-materials with high sensitivity. The spherical silica beads with the brunauer-emmett-telle(BET) average pore size of 15 nm were prepared with a ratio 1, 3, 5-trimethylbenzen, as a swelling agent, to the block-copolymer template surfactant of over 1 and under vigorous mixing condition. The surface of spherical mesoporous silica is modified using octadecylsilane for incorporating QDs. Based on photoluminescence(PL) spectra, the relative brightness of mesoporous silica beads incorporated with 10 nM of QDs is 79,000 times brighter than that of Rodamine 6 G.