• 비파괴검사학회지
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• 제34권5호
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• pp.377-383
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• 2014

위치 감응형 전극 네트워크(addressable conducting network, ACN)는 탄소섬유 복합재료와 전극 사이의 접촉저항을 통해 구조물의 손상 감지가 가능하다. 손상 감지를 위한 위치 감응형 전극 네트워크의 신뢰성을 향상시키기 위해서는 전극과 복합재료 사이의 접촉저항이 최소화되어야 한다. 본 연구에서는 은 나노 전극을 탄소섬유 복합재료 위에 인쇄전자기술을 이용하여 제작하였다. 은 전극이 형성된 복합재료는 은 나노 잉크의 소결온도와 복합재료의 표면거칠기에 따라 제작되었으며, 이에 따른 접촉저항을 측정하였다. 또한, 전자주사현미경(scanning electron microscope, SEM)을 통해 전극과 복합재료 사이의 계면을 관찰하였다. 본 연구를 통해, 은 나노 잉크의 소결온도가 $120^{\circ}C$, 복합재료의 표면거칠기가 0.230a일 때, $0.3664{\Omega}$의 최소 접촉저항을 나타냈다.

• JSTS:Journal of Semiconductor Technology and Science
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• 제14권2호
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• pp.153-162
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• 2014

We show that carbon nanotube sensors with gold particles on the single-walled carbon nanotube (SWNT) network operate as Schottky barrier transistors, in which transistor action occurs primarily by varying the resistance of Au-SWNT junction rather than the channel conductance modulation. Transistor characteristics are calculated for the statistically simplified geometries, and the sensing mechanisms are analyzed by comparing the simulation results of the MOSFET model and Schottky junction model with the experimental data. We demonstrated that the semiconductor MOSFET effect cannot explain the experimental phenomena such as the very low limit of detection (LOD) and the logarithmic dependence of sensitivity to the DNA concentration. By building an asymmetric concentric-electrode model which consists of serially-connected segments of CNTFETs and Schottky diodes, we found that for a proper explanation of the experimental data, the work function shifts should be ~ 0.1 eV for 100 pM DNA concentration and ~ 0.4 eV for $100{\mu}M$.

• 한국축산식품학회지
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• 제33권4호
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• pp.463-473
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• 2013

Through the development of efficient data collecting technologies like RFID, and inter-enterprise collaboration platforms such as web services, companies which participate in supply chains can acquire visibility over the whole supply chain, and can make decisions to optimize the overall supply chain networks and processes, based on the extracted knowledge from historical data collected by the visibility system. Although not currently active, the MeatWatch system has been developed, and is used in part for this purpose, in the imported beef distribution network in Korea. However, the imported beef distribution network is too complicated to analyze its various aspects using ordinary process analysis approaches. In this paper, we suggest a novel approach, called RFID-based supply chain process mining, to automatically discover and analyze the overall supply chain processes from the distributed RFID event data, without any prior knowledge. The proposed approach was implemented and validated, by using a case study of the imported beef distribution network in Korea. Specifically we demonstrated that the proposed approach can be successfully applied to discover supply chain networks from the distributed event data, to simplify the supply chain networks, and to analyze anomaly of the distribution networks. Such novel process mining functionalities can reinforce the capability of traceability services like MeatWatch in the future.

• 한국방사선학회논문지
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• 제18권1호
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• pp.21-26
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• 2024

You only look once v5 (YOLOv5)는 객체 검출 과정에 우수한 성능을 보이고 있는 딥러닝 모델 중 하나다. 그러므로 본 연구의 목적은 양전차방출단층촬영 팬텀 영상에서 다양한 하이퍼 파라미터에 따른 YOLOv5 모델의 성능을 평가했다. 데이터 세트는 500장의 QIN PET segmentation challenge로부터 제공되는 오픈 소스를 사용하였으며, LabelImg 소프트웨어를 사용하여 경계박스를 설정했다. 학습의 적용된 하이퍼파라미터는 최적화 함수 SDG, Adam, AdamW, 활성화 함수 SiLu, LeakyRelu, Mish, Hardwish와 YOLOv5 모델 크기에 따라 nano, small, large, xlarge다. 학습성능을 평가하기 위한 정량적 분석방법으로 Intersection of union (IOU)를 사용하였다. 결과적으로, AdmaW의 최적화 함수, Hardwish의 활성화 함수, nano 크기에서 우수한 객체 검출성능을 보였다. 결론적으로 핵의학 영상에서의 객체 검출 성능에 대한 YOLOV5 모델의 유용성을 확인하였다.

• Genomics & Informatics
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• 제5권3호
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• pp.133-136
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• 2007

The Gene Set network viewer (GSnet) visualizes the functional enrichment of a given gene set with a protein interaction network and is implemented as a plug-in for the Cytoscape platform. The functional enrichment of a given gene set is calculated using a hypergeometric test based on the Gene Ontology annotation. The protein interaction network is estimated using public data. Set operations allow a complex protein interaction network to be decomposed into a functionally-enriched module of interest. GSnet provides a new framework for gene set analysis by integrating a priori knowledge of a biological network with functional enrichment analysis.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 제37회 하계학술대회 논문집 D
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• pp.1783-1784
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• 2006

A laser interferometer is the unique measurement device that can measure the range up to a few meters with sub-nano resolution and this characteristic makes it as the important sensing device for the emerging nano-mechatronics technologies. The laser interferometer, however, is very sensitive to the environments such as temperature, humidity, sound noises, vibrations and air turbulences and these factors result in a few hundred nano meter errors. There have been many efforts to reduce these environmental errors. The output of the laser interferometer is assumed to be the sum of a real displacement and a Markov process noise. The purpose of this paper is to develop Kalman filter algorithms to reduce the laser interferometer measurement errors by exploiting the information of displacements in position-servo systems.

• 한국세라믹학회지
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• 제39권4호
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• pp.336-340
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• 2002

Pure and nano-sized $TiO_2$ and $CaTiO_3$ powders were fabricated by a polymeric steric entrapment route and planetary milling process. An ethylene glycol was used as a polymeric carrier for the preparation of organic-inorganic precursors. Titanium isopropoxide and calcium nitrate were dissolved in liquid-type ethylene glycol without any precipitation. At the optimum amount of the polymer, the metal cations were dispersed in solution and a homogeneous polymeric network was formed. The dried precursor ceramic gels were turned to porous powders through calcination process. The porous powders were crystallized at low temperatures and the crystalline powders were planetary milled to nano size.

• 한국정보통신학회논문지
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• 제26권5호
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• pp.668-674
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• 2022

시각 정보를 이용한 기계 학습 기술은 주변 상황 인지, 결함 감지, 보안 그리고 사용자 분석과 같이 산업, 서비스 분야에서 활용성이 높아졌다. 그 중 CCTV 영상 분석을 통한 사용자 분석은 시각 정보를 잘 활용하는 실용적인 부분이라고 할 수 있다. 또한 이러한 임베디드 환경에서의 실용성을 높이기 위한 신경 회로망 경량화에 대한 연구가 지속되고 있다. 본 논문에서는 디스플레이형 자판기인 키오스크에서 활용할 수 있는 사람 및 얼굴 검출과 사용자의 나이 및 성별 분류 시스템을 제안한다. 제안하는 모델은 MobileNet, YOLOv2, 생략 연결을 기반으로 설계되었으며, 검출과 분류 망을 개별적으로 학습한 뒤 결합한 2-stage 구조를 띈다. 또한 주의 집중 기법을 사용하여 시스템의 성능을 향상시키고자 하였다. 제안하는 시스템에 대한 구동과 성능 평가는 소형 그래픽 처리 유닛인 Nvidia Jetson Nano에서 진행하였다.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2006년도 추계학술대회
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• pp.443-446
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• 2006

Carbon-supported Platinum (Pt) is the potential electro-catalyst material for anodic and cathodic reactions in fuel cell. Catalytic activity of the metal strongly depends on the particle shape, size and distribution of the metal in the porous supportive network. Conventional preparation techniques based on wet impregnation and chemical reduction of the metal precursors often do not provide adequate control of particle size and shape. We have proposed a novel route for preparing nano sized Pt colloidal particles in solution by oxidation of ethylene glycol. These Pt nano particles were deposited on large surface area carbon support. The process of nano Pt colloid formation involves the oxidation of solvent ethylene glycol to mainly glycolic acid and the presence of its anion glycolate depends on the solution pH. In the process of colloidal Pt formation glycolate actsas stabilizer for the Pt colloidal particle and prevents the agglomeration of colloidal Pt particles. These mono disperse Pt particles in carbon support are found uniformly distributed in nearly spherical shape and the size distribution was narrow for both supported and unsupported metals. The average diameter of the Pt nano particle was controlled in the range off to 3 nm by optimizing reaction parameters. Transmission electron microscopy, CV and RRDE experiments were used to compliment the results.

• BMB Reports
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• 제44권1호
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• pp.1-10
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• 2011

Inter-cellular communication via diffusible small molecules is a defining character not only of multicellular forms of life but also of single-celled organisms. A large number of bacterial genes are regulated by the change of chemical milieu mediated by the local population density of its own species or others. The cell density-dependent "autoinducer" molecules regulate the expression of those genes involved in genetic competence, biofilm formation and persistence, virulence, sporulation, bioluminescence, antibiotic production, and many others. Recent innovations in recombinant DNA technology and micro-/nano-fluidics systems render the genetic circuitry responsible for cell-to-cell communication feasible to and malleable via synthetic biological approaches. Here we review the current understanding of the molecular biology of bacterial intercellular communication and the novel experimental protocols and platforms used to investigate this phenomenon. A particular emphasis is given to the genetic regulatory circuits that provide the standard building blocks which constitute the syntax of the biochemical communication network. Thus, this review gives focus to the engineering principles necessary for rewiring bacterial chemo-communication for various applications, ranging from population-level gene expression control to the study of host-pathogen interactions.