• Title/Summary/Keyword: 구조적성능

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Development of Prussian Blue-laden Magnetic Janus Micro-adsorbents for Remediation of Cs+ Ions in Wastewater (프러시안 블루가 함입된 자성 야누스 미세 흡착제 개발 및 이를 이용한 폐수 내 세슘정화)

  • Ju-Eon Jung;Dong-Hyeon Kyoung;Sung-Min Kang
    • Korean Chemical Engineering Research
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    • v.62 no.2
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    • pp.181-190
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    • 2024
  • Here, we develop a centrifugal microfluidic reactor with simple, fast, and high-throughput manner for the generation of magnetic Janus micro-adsorbents (MAs). By using the multi-micronozzle consisting of two separate aligned needles and centrifugal tubes, we have synthesized highly monodispersed Prussian blue- and magnetic nanoparticle-laden micro-adsorbents (PB-MNP-MAs). The enhanced cesium (Cs+) adsorption was demonstrated by conducting the adsorption isotherm and kinetics experiment which can be contributed to the porous nature of the Ca-alginate networks with a high surface area of embedded PB nanoparticles, resulting to perform rapid adsorption activity within 10 min. After Cs+ adsorption process, the as-synthesized PB-MNP-MAs were successfully harvested by introducing the external magnetic fields. Therefore, we believe that our findings can be provided new direction towards the development of advanced functional adsorbents in biological and environmental fields.

Comparison of Residential Environment by Public Rental Housing Type: Focusing on Failing to Meet the Minimum Housing Standard (공공임대주택의 유형별 주거환경 비교 분석: 최저주거기준 미달을 중심으로)

  • DaEun Lee;JiYoung Oh
    • Land and Housing Review
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    • v.15 no.1
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    • pp.23-38
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    • 2024
  • This study examined the residential environment of public rental housing by type at a microscale, using ANOVA and multinominal logistic models, based on the minimum and specific housing standards. The key findings are as follows. First, it was confirmed that each type of public rental housing, as well as resident characteristics, varied in meeting the minimum and specific housing standards. Second, Happy House turned out to have the worst residential environments, as a high proportion of this type did not meet the minimum housing standard and the remaining specific standards, excluding facility standards. Third, among permanent rental, national rental, and purchase/jeonse rental housing types, permanent rental housing was poor by the minimum housing standards, and area and room standards, while purchase and jeonse rental housing types showed a high proportion of failure to meet structural, performance, and environmental standards. Fourth, it was confirmed that purchase/jeonse rentals had higher rental anxiety than other types of public rental housing. In particular, anxiety about rent increases and the loss of deposits was high. These findings suggest that public efforts are called for to improve the residential environment through tailored support, depending on the type of public rental housing.

Research Trends in Thermal Interface Materials for Flexible and Stretchable Electronic Device (유연신축성 전자 디바이스를 위한 열계면 소재 연구동향)

  • Young-Joo Park;Geon-Joo Jeong;Kwang-Seok Kim
    • Journal of the Microelectronics and Packaging Society
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    • v.31 no.1
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    • pp.7-15
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    • 2024
  • In the trend of the multi-functionalization, miniaturization, and increased power output trends of flexible and stretchable electronic devices, the development of materials or structures with superior heat transfer characteristics has become a pressing issue. Traditional thermal interface materials (TIM) fail to meet the heat dissipation requirements of flexible and stretchable electronic devices, which must endure rapid bending, twisting, and stretching. To address this challenge, there is a demand for the development of TIM that simultaneously possesses high thermal conductivity and stretchability. This paper examines the research trends of liquid metal, carbon, and ceramic-based stretchable thermal interface materials and explores effective strategies for enhancing their thermal and mechanical properties.

A Study for Implementation of Autonomous Maritime Radio Devices using LMX2571 (LMX2571을 활용한 자율해상무선기기 기술 구현에 관한 연구)

  • Chong-Lyong, Pag
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.30 no.2
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    • pp.217-225
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    • 2024
  • Even after the introduction of Global Maritime Distress and Safety System (GMDSS), many maritime accidents occur. A method of transmitting a rescue signal when a person falls into the water from a ship is currently being researched and developed in various ways, but no products have been developed that use frequencies allocated for maritime mobile service. Accordingly, in this study, we designed and produced a man-over-board (MOB) device by applying Group B AMRD technologies, which were adopted through the latest revision of the International Telecommunication Union (ITU). In addition, a receiver and user interface were built to verify the performance of the transmitter, and we confirmed that it can be used in conjunction with existing electronic charts. This MOB device satisfies the general and technical requirements of Group B AMRD using AIS technology and uses integrated components for miniaturization for easy portability in a maritime environment. We expect that it will achieve excellent AIS communication and be essential in rapid response and safety in emergency scenarios.

A Study on the Direction of Cyber Forces Development in the Korean military through Changes in Germany's Cyber Warfare Response Policy (독일의 사이버전 대응 정책변화를 통해 본 한국군 사이버전력 발전 방안에 관한 연구)

  • Sangjun Park;Taesan Kim;Jee-won Kim;Chan-gi Jung
    • Convergence Security Journal
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    • v.21 no.4
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    • pp.59-68
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    • 2021
  • The Future Battlefield includes the main areas of modern warfare, including the ground, sea, and air, as well as cyberspace and space. Cyberspace consists of computers, wired and wireless networks, and spans the ground, sea, air, and space domains. Cyber warfare takes place in cyberspace, so it is not easy for people without expertise in cyber to recognize the cyber situation. Therefore, training personnel with professional knowledge and skills in cyber is paramount in preparation for cyber warfare. In particular, the results of cyber warfare will vary greatly depending on the ability of cyber combatants to carry it out, the performance of cyber systems, and the proficiency of cyber warfare procedures. The South Korean military has power to respond to cyber warfare at various levels, centering on the Cyber Operations Command, but there is a limit to defending all the rapidly expanding cyberspace. In this paper, to overcome these limitations, we looked at the changes in Germany's cyber warfare response policy. Based on them, the organization structure, weapon system, and education and training system of future Korean military cyber forces are presented separately.

Privacy-Preserving Cryptographic API Misuse Detection Framework Using Homomorphic Encryption (동형 암호를 활용한 프라이버시 보장 암호화 API 오용 탐지 프레임워크)

  • Seungho Kim;Hyoungshick Kim
    • Journal of the Korea Institute of Information Security & Cryptology
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    • v.34 no.5
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    • pp.865-873
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    • 2024
  • In this study, we propose a privacy-preserving cryptographic API misuse detection framework utilizing homomorphic encryption. The proposed framework is designed to effectively detect cryptographic API misuse while maintaining data confidentiality. We employ a Convolutional Neural Network (CNN)-based detection model and optimize its structure to ensure high accuracy even in an encrypted environment. Specifically, to enable efficient homomorphic operations, we leverage depth-wise convolutional layers and a cubic activation function to secure non-linearity, enabling effective misuse detection on encrypted data. Experimental results show that the proposed model achieved a high F1-score of 0.978, and the total execution time for the homomorphically encrypted model was 11.20 seconds, demonstrating near real-time processing efficiency. These findings confirm that the model offers excellent security and accuracy even when operating in a homomorphic encryption environment.

An Experimental Study on Flexural Strength of SC Composite Beams Enforced by Unbonded Post Tension (비부착 포스트텐션 SC합성보의 휨내력에 관한 실험적 연구)

  • Kim, Heui Cheol;Ahn, Hyung Joon;Ryu, Soo Hyun
    • Journal of Korean Society of Steel Construction
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    • v.21 no.2
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    • pp.135-144
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    • 2009
  • This study aims to suggest an appropriate flexural reinforcement technique by evaluating the reinforcement capacity of specimens that underwent flexural reinforcement according to the post-tension method with the anchoring position of an unbonded tension member on the conventional SC composite beam and the applied tension level as variables. For the experiment, up to a predetermined yield load was applied to each type of specimen and then, unbounded post-tensioning was additionally conducted to examine its reinforcement capacity. The analysis of the said experiment showed that the post-reinforced SC composite beam was characterized by significantly improved yield stress and initial stiffness, compared with the pre-reinforced one and the experimental measurements/theoretical values of maximum stress ranged from 0.95 to 1.13 following reinforcement. There was little or no change depending on the maximum stress and tension in the specimen (D160, Class 240) whose neutral axis and upper part had anchoring devices mounted prior to reinforcement. Rather, the ductility decreased with the increasing tension. On the contrary, in the case of the other specimen (Class D120) whose neutral axis had anchoring devices mounted after reinforcement, both the maximum stress and ductility increased with increasing tension, which indicates that the latter tension reinforcement was reasonably appropriate and effective for the neutral axis reinforcement.

Performance Evaluation of Component Detectors of Double-scattering Compton Camera (이중 산란형 컴프턴 카메라 구성 검출기 성능 평가)

  • Seo, Hee;Park, Jin-Hyung;Kim, Chan-Hyeong;Lee, Ju-Hahn;Lee, Chun-Sik;Lee, Jae-Sung
    • Journal of Radiation Protection and Research
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    • v.35 no.2
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    • pp.69-76
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    • 2010
  • Prototype double-scattering Compton camera, which consists of three gamma-ray detectors, that is, two double-sided silicon strip detectors (DSSDs) as scatterer detectors and a NaI(Tl) scintillation detector as an absorber detector, could provide high imaging resolution with a compact system. In the present study, the energy resolution and the timing resolution of component detectors were measured, and the parameters affecting the energy resolution of the DSSD were examined in terms of equivalent noise charge (ENC). The energy resolutions of the DSSD-1 and DSSD-2 were, in average, $25.2keV{\pm}0.8keV$ FWHM and $31.8keV{\pm}4.6keV$ FWHM at the 59.5 keV peak of $^{241}Am$, respectively. The timing resolutions of the DSSD and NaI(Tl) scintillation detector were 57.25 ns FWHM and 7.98 ns FWHM, respectively. In addition, the Compton image was obtained for a point-like $^{137}Cs$ gamma source with double-scattering Compton camera. From the present experiment, the imaging resolution of 8.4 mm FWHM (angular resolution of $8.1^{\circ}$ FWHM), and the imaging sensitivity of $1.5{\times}10^{-7}$ (intrinsic efficiency of $1.9{\times}10^{-6}$) were obtained.

Horizontal Behavior Characteristics of Umbrella-Type Micropile Applied in Soft Clay Ground subjected to Seismic Motion (연약점토지반에 적용한 우산형 마이크로파일의 지진시 수평거동 특성)

  • Kim, Soo-Bong;Son, Su-Won;Kim, Jin-Man
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.21 no.6
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    • pp.687-695
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    • 2020
  • Micropile is used to improve the stability of existing structures as well as solve various geotechnical problems, such as suppressing slope activity and shearing keys of retaining walls. The existing micropile method has a significantly less capacity to resist a horizontal force than a vertical force0355 Therefore, it is necessary to develop and study an umbrella-type micropile method with excellent seismic performance that can secure seismic performance economically while minimizing structures and ground disturbance areas in the limited space of existing structures. In this study, numerical analysis was performed on the umbrella-type micropile, in which the sloped pile and vertical pile were combined, and the horizontal behavior in soft clay ground during earthquakes was analyzed. Numerical analysis showed that umbrella-type micropile suppresses horizontal displacement in soft ground, and the effect of reducing the horizontal displacement was more pronounced when the embedded depth of the slope pile was 15 m or more. The embedded depth of the micropile and horizontal displacement suppression effect was proportional. Therefore, the umbrella-type micropile has an excellent effect of suppressing horizontal displacement during earthquakes on soft clay ground.

A Fast Motion Estimation Algorithm Based on Multi-Resolution Frame Structure (다 해상도 프레임 구조에 기반한 고속 움직임 추정 기법)

  • Song, Byung-Cheol;Ra, Jong-Beom
    • Journal of the Institute of Electronics Engineers of Korea SP
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    • v.37 no.5
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    • pp.54-63
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    • 2000
  • We present a multi-resolution block matching algorithm (BMA) for fast motion estimation At the coarsest level, a motion vector (MV) having minimum matching error is chosen via a full search, and a MV with minimum matching error is concurrently found among the MVs of the spatially adjacent blocks Here, to examine the spatial MVs accurately, we propose an efficient method for searching full resolution MV s without MV quantization even at the coarsest level The chosen two MV s are used as the initial search centers at the middle level At the middle level, the local search is performed within much smaller search area around each search center If the method used at the coarsest level is adopted here, the local searches can be done at integer-pel accuracy A MV having minimum matching error is selected within the local search areas, and then the final level search is performed around this initial search center Since the local searches are performed at integer-pel accuracy at the middle level, the local search at the finest level does not take an effect on the overall performance So we can skip the final level search without performance degradation, thereby the search speed increases Simulation results show that in comparison with full search BMA, the proposed BMA without the final level search achieves a speed-up factor over 200 with minor PSNR degradation of 02dB at most, under a normal MPEG2 coding environment Furthermore, our scheme IS also suitable for hardware implementation due to regular data-flow.

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