• 제목/요약/키워드: U-shaped network

검색결과 17건 처리시간 0.021초

Restoring Turbulent Images Based on an Adaptive Feature-fusion Multi-input-Multi-output Dense U-shaped Network

  • Haiqiang Qian;Leihong Zhang;Dawei Zhang;Kaimin Wang
    • Current Optics and Photonics
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    • 제8권3호
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    • pp.215-224
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    • 2024
  • In medium- and long-range optical imaging systems, atmospheric turbulence causes blurring and distortion of images, resulting in loss of image information. An image-restoration method based on an adaptive feature-fusion multi-input-multi-output (MIMO) dense U-shaped network (Unet) is proposed, to restore a single image degraded by atmospheric turbulence. The network's model is based on the MIMO-Unet framework and incorporates patch-embedding shallow-convolution modules. These modules help in extracting shallow features of images and facilitate the processing of the multi-input dense encoding modules that follow. The combination of these modules improves the model's ability to analyze and extract features effectively. An asymmetric feature-fusion module is utilized to combine encoded features at varying scales, facilitating the feature reconstruction of the subsequent multi-output decoding modules for restoration of turbulence-degraded images. Based on experimental results, the adaptive feature-fusion MIMO dense U-shaped network outperforms traditional restoration methods, CMFNet network models, and standard MIMO-Unet network models, in terms of image-quality restoration. It effectively minimizes geometric deformation and blurring of images.

U자형 구조의 피로특성에 대한 잔류응력의 영향 평가 (Evaluation of Residual Stress Effect about Fatigue Characteristic of U-shaped Structure)

  • 김상영;구재민;석창성;모진용
    • 한국정밀공학회지
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    • 제27권4호
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    • pp.79-86
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    • 2010
  • Mechanical structures with power sources experience repeated force produced by motors. In result, the life of the pipes reduces and ultimately, the pipes collapse. Such pipes are formed into several shapes and particularly, the U-shape pipe is damaged frequently. In most cases, the U-shape pipe is made with a straight pipe by complicated bending work. During this work process, plastic deformation of the pipe produces residual stress in the pipe. This residual stress significantly affects the fracture behavior of the pipe and induces the change of the stress ratio (min. stress/Max. stress = R). For this reason, residual stress has to be evaluated. In this paper, the residual stress of a U-shaped pipe was evaluated by FEM analysis. In addition, fatigue tests of the U-shaped pipe were performed by using a uniaxial fatigue testing machine. The results of the fatigue test were modified with the results of FEM (Finite Element Method) analysis for residual stress. The modified fatigue test results of the U-shaped pipe were compared with those of a straight pipe.

5GHz 대역에서 트리플 U-슬롯 모양의 마이크로스트립 안테나 설계 및 제작 (Fabrication and Measurement of Triple U-shaped slot Microstrip Antenna in 5GHz band)

  • 강문규;정유근;주정민;정계택;윤중한;곽경섭
    • 전기전자학회논문지
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    • 제8권1호
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    • pp.86-95
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    • 2004
  • 본 논문에서는 기존의 연구에서 이루어진 HiperLAN 대역의 무선 LAN용 U-슬롯 모양의 안테나에 HiperLAN 1/2 및 5GHz 대역의 ISM 밴드의 대역폭 범위까지 다룰 수 있는 안테나를 설계하고, 제작하였다. 기본 U-슬롯 모양의 구조에 두 개의 U-슬롯 모양을 추가하여 새로운 모델을 제안하였다. 접지면과 기판 사이에 공기층을 삽입하여 VSWR<1.5에서 충분한 대역을 얻을 수 있도록 하였고, 안테나의 이득은 $6.27{\sim}9.82dBi$를 얻었다. 방사 패턴은 주파수 대역에서 안정된 패턴을 얻었다.

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MEDU-Net+: a novel improved U-Net based on multi-scale encoder-decoder for medical image segmentation

  • Zhenzhen Yang;Xue Sun;Yongpeng, Yang;Xinyi Wu
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • 제18권7호
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    • pp.1706-1725
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    • 2024
  • The unique U-shaped structure of U-Net network makes it achieve good performance in image segmentation. This network is a lightweight network with a small number of parameters for small image segmentation datasets. However, when the medical image to be segmented contains a lot of detailed information, the segmentation results cannot fully meet the actual requirements. In order to achieve higher accuracy of medical image segmentation, a novel improved U-Net network architecture called multi-scale encoder-decoder U-Net+ (MEDU-Net+) is proposed in this paper. We design the GoogLeNet for achieving more information at the encoder of the proposed MEDU-Net+, and present the multi-scale feature extraction for fusing semantic information of different scales in the encoder and decoder. Meanwhile, we also introduce the layer-by-layer skip connection to connect the information of each layer, so that there is no need to encode the last layer and return the information. The proposed MEDU-Net+ divides the unknown depth network into each part of deconvolution layer to replace the direct connection of the encoder and decoder in U-Net. In addition, a new combined loss function is proposed to extract more edge information by combining the advantages of the generalized dice and the focal loss functions. Finally, we validate our proposed MEDU-Net+ MEDU-Net+ and other classic medical image segmentation networks on three medical image datasets. The experimental results show that our proposed MEDU-Net+ has prominent superior performance compared with other medical image segmentation networks.

5GHz대역 무선랜용 소형 광대역 안테나 설계 (The Design of Compact and wideband antenna for wireless LAN at 5GHz band)

  • 박경수;최성열;신필수;고영호
    • 대한전자공학회논문지TC
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    • 제41권6호
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    • pp.93-99
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    • 2004
  • 무선랜에 대한 수요의 급격한 증가로 HyperLAN(5.1-533GHz, 5.725-5.825GHz)이 전세계 적으로 무선랜을 위하여 새롭게 할당되고 있다. 또한 대부분의 이동통신기기는 크기가 작으므로 안테나의 크기는 효과적인 설계를 위해 매우 중요하다. 본 논문에서는 5GHz 무선랜을 위해 소형 광대역 안테나를 설계하였다. U슬롯 안테나는 간단한 구조이지만 $10-40\%$의 광대역을 가지고 있으며, 또한 좋은 방사특성을 가지고 있다. 그러나, 일반적으로 U슬롯 안테나의 크기는 크므로 PDA나 노트북과 같은 무선통신기기에 적용하기에 어려움이 있다. 제안된 안테나는 사각패치에 U형 슬롯을 이용하여 광대역 특성을 얻었고, 두 개의 유전체 기판과 스티로폼을 이용함으로써 소형화하였다. U슬롯 안테나의 설계를 위해 유한차분시간영역(FDTD) 법이 적용되었고 MPI 병렬화기법을 이용하여 FDTD법의 분석속도를 향상하였다.

글로벌 가치사슬에서 전방참여와 후방참여가 소득불평등에 미치는 영향 (Participation in GVCs and Income Inequality)

  • 이가은;최영준
    • 무역학회지
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    • 제44권2호
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    • pp.269-282
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    • 2019
  • This study analyzes the effects of participation in the global production network on the income inequality using panel data from 2005 to 2016 for 63 countries. In this study were used fixed effects model with autocorrelation, random effect model with autocorrelation and the GLS method. Results are as follows: First, the economic development level supports the Kuznets hypothesis. And then, the forward participation in global value chains increased income inequality, and the backward participation decreased income inequality. In order to derive more detailed estimation results, we analyzed OECD countries and non-OECD countries. First, OECD countries featured decreased, but increased beyond a certain level as a U-shaped curve, that did not support the Kuznets hypothesis. In contrast, non-OECD countries followed the Kuznets U-curve. Second, participation in the global production network showed that both OECD and non-OECD countries featured increased income inequality. In contrast, backward participation appears to mitigate income inequality both in OECD and non-OECD countries. Finally, the ratio of labor and capital is significant in mitigating income inequality in non-OECD countries in which they feature backward participation in production networks. This can be interpreted as developing economies participate in the global production network due to increased capital accumulation and increased the labor productivity.

네트워크 중심성과 성과에 관한 연구: 영화산업을 중심으로 (Relationship between Genre Centrality and Performance in the Motion Picture Industry)

  • 이원희;정동일
    • 한국콘텐츠학회논문지
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    • 제17권6호
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    • pp.153-168
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    • 2017
  • 영화 장르에 대한 기존 연구는 특정 장르와 영화 성과간의 유의성 검증에 집중하였다. 그러나 기존 연구는 대상 국가 및 시기에 따라 서로 다른 결과를 보여주고 있어 이론적, 실무적 시사점을 얻는 데 어려움이 있으며 주로 단일 장르와 성과 간의 관계에 집중했기 때문에, 최근 중요하게 부각되고 있는 복합 장르 문제를 이해하는 데 한계를 가지고 있다. 본 연구에서는 사회연결망 분석 방법과 복합 장르 자료를 활용하여 장르 간 네트워크를 구성하고 장르 중심성과 영화 성과와의 관계를 분석하였다. 연구 결과 장르 중심성과 영화 성과 간에는 역 U 형태의 관계가 있는 것으로 확인되었다. 이는 지나친 '탐색'과 지나친 '활용'보다는 이 둘 간의 직절한 균형이 필요하다는 이론적 주장을 지지하는 결과이다. 본 연구는 실무적 차원에서 영화 장르의 범위와 조합을 선택하는 데에도 유용하게 활용할 수 있을 것이다. 향후 연구에서 연구 대상을 확대하고 장르 간 연결에 대한 질적 분석을 수행한다면 연구의 신뢰성을 높일 수 있을 것으로 기대하며 영화산업의 성장과정과 연계한 장르 네트워크의 동적 연구로도 확장 가능할 것이다.

조직의 여유자원과 혁신간의 비선형관계에 관한 연구 : 네트워크 다양성 조절효과 (A Study on the Curvilinear Relationship Between Slack and Innovation : Focus on Moderating Effect of Network Diversity)

  • 강소라;한수진
    • Journal of Information Technology Applications and Management
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    • 제27권6호
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    • pp.181-196
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    • 2020
  • Based on the resource-based perspective, this study seeks to understand the relationship between the organizational slack and innovation, and to demonstrate that there exists a difference in the influence of the organizational slack according to the type of innovation by dividing the types of innovation into exploratory and exploitative innovations. They also want to understand the role that network diversity plays in the relationship between organizational slack and innovation. For this purpose, hypothesis and research models were presented based on resource-based perspectives and empirical analysis was conducted on 171 companies. The analysis confirmed that the impact of organizational slack on exploitative innovation is linear, not non-linear, as expected. In other words, the more resources available, the more productive the enterprise is, and the more resources available to the organization have a positive impact on the innovation. On the other hand, exploratory innovation represented an inverse U-shaped relationship between organizational slack and nonlinearity as expected. The control effect of network diversity was only seen in the relationship between organizational slack and exploratory innovation. Through this study, it provides implications such as the importance of network diversity, which is a relationship between companies, and the difference in the utilization of organizational slack according to the type of innovation.

Compact Mobile Quad-Band Slot Antenna Design for GPS L1, WiMAX, and WLAN Applications

  • Piao, Haiyan;Jin, Yunnan;Tak, Jinpil;Choi, Jaehoon
    • Journal of electromagnetic engineering and science
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    • 제17권2호
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    • pp.57-64
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    • 2017
  • In this paper, an asymmetric compact multiband slot antenna is proposed for global positioning system (GPS), worldwide interoperability for microwave access (WiMAX), and wireless area network (WLAN) applications. The top plane, a ground is composed of a rectangular slot with a trapezoidal-like stub, an inverted U-shaped slot at the right side of the rectangular slot, an inverted L-shaped slot at the left side of the rectangular slot, and three stubs. The proposed antenna is fed by an asymmetric cross-parasitic strip on the bottom plane. By properly designing the slots and stubs, four resonant frequency bands are achieved with -10 dB reflection coefficient bandwidths of 50 MHz, 400 MHz, 390 MHz, and 830 MHz in the 1.57 GHz GPS band, 2.4 GHz WLAN band, 3.5 GHz WiMAX band, and 5.5 GHz WLAN bands, respectively. The antenna has a total compact size of $13mm{\times}32mm{\times}0.8mm$. Simulated and measured results indicate that the proposed antenna has sufficient bandwidth and good radiation performance in each band.

암반 열물성과 지하공간 환경분석 연구 (A study on the relationship between the thermal properties of rock and the enviroment in underground spaces)

  • 이창우
    • 터널과지하공간
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    • 제6권4호
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    • pp.335-341
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    • 1996
  • This fundamental study analyzes the relationship between rock thermal properties and psychrometric properties in underground space and has a ultimate goal to develope technologies for predicting major environmental variables. The study is divided into 2 subjects (1) developement of a basic model for predicting temperature and humidity, (2) analysis of the validity of the model through application to a local underground storage space for military supplies. The basic model is built for the network of tunnel-shaped underground spaces. The model takes into account rock thermal properties and changes in moisture content in the air due to condensation/evaporation on the rock surface. Using lumped-parameter analytical method, heat flux from or to the surrounding rock is calculated and then the psychrometric properties(air quantity, pressure, temperature, humidity) are estimated through network simulation. The model can be utilized regardless of the tunnel type. The study site is a local storage space built in rock, mainly granite gneiss and quartz-porphyry. It is a U-shaped tunnel, 593.5m long and 6x6.5m wide. Relative humidity inside has to be strictly controlled under 55% to avoid erosion of a certain types of supplies stored in 6 chambers with the capacity of 300~1.000 ton. The thermal conductivity varies between 2.734 and 2.779W/m$^{\circ}C$ and the thermal diffusivity is in the range of 1.119 and $1.152{\times}10^{-6}\;m^2/s$ the specific heat between 910 and $920\;J/kg^{\circ}C$. Relative errors of the predicted values of dry/wet temperature and relative humidity are 0.8~3.0%, 0~7.5% and 0~7.0%, respectively. Apparent errors associated with the rock surface temperature seems to be partly due to the intrinsic limitations in the infrared thermometer used in this study.

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