• Title/Summary/Keyword: Over-fitting

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헴트 소자의 해석적 직류 모델 (AN ANALYTICAL DC MODEL FOR HEMTS)

  • 김영민
    • ETRI Journal
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    • 제11권2호
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    • pp.109-119
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    • 1989
  • Based on the 2-dimensional charge-control simulation[4], a purely analytical model for MODFET's is proposed. In this model, proper treatment of the diffusion effect in the 2-DEG transport due to the gradual channel opening along the 2-DEG channel was made to explain the enhanced mobility and increased thershold voltage. The channel thickness and gate capacitance are experssed as functions of gate vlotage including subthreshold characteristics of the MODFET's analytically. By introducing the finite channel opening and an effective channel-length modulation, the slope of the saturation region of the I-V curves was modeled. The smooth transition of the I-V curves from linear-to-saturation region of the I-V curves was possible using the continuous Troffimenkoff-type of field-dependent mobility. Furthermore, a correction factor f was introduced to account for the finite transtition section forming between the GCA and the saturated section. This factor removes the large discrepanicies in the saturation region fo the I-V curves presicted by existing 1-dimensional models. The fitting parameters chosen in our model were found to be predictable and vary over relatively small range of values.

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얼굴 표정 인식을 위한 Convolutional Neural Networks (Convolutional Neural Networks for Facial Expression Recognition)

  • 최인규;송혁;유지상
    • 한국방송∙미디어공학회:학술대회논문집
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    • 한국방송∙미디어공학회 2016년도 추계학술대회
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    • pp.17-18
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    • 2016
  • 본 논문에서는 딥러닝 기술 중의 하나인 CNN(Convolutional Neural Network) 기반의 얼굴 표정 인식 기법을 제안한다. 제안한 기법에서는 획득한 여섯 가지 주요 표정의 얼굴영상들을 학습 데이터로 이용할 때 분류 성능을 저해시키는 과적합(over-fitting) 문제를 해결하기 위해서 데이터 증대 기법(data augmentation)을 적용한다. 또한 기존의 CNN 구조에서 convolutional layer 및 node의 수를 변경하여 학습 파라미터 수를 대폭 감소시킬 수 있다. 실험 결과 제안하는 데이터 증대 기법 및 개선한 구조가 높은 얼굴 표정 분류 성능을 보여준다는 것을 확인하였다.

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화살 탄착점 측정을 위한 레이저 스캔 카메라 파라미터 보정 (Parameter Calibration of Laser Scan Camera for Measuring the Impact Point of Arrow)

  • 백경동;천성표;이인성;김성신
    • 한국생산제조학회지
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    • 제21권1호
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    • pp.76-84
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    • 2012
  • This paper presents the measurement system of arrow's point of impact using laser scan camera and describes the image calibration method. The calibration process of distorted image is primarily divided into explicit and implicit method. Explicit method focuses on direct optical property using physical camera and its parameter adjustment functionality, while implicit method relies on a calibration plate which assumed relations between image pixels and target positions. To find the relations of image and target position in implicit method, we proposed the performance criteria based polynomial theorem model that overcome some limitations of conventional image calibration model such as over-fitting problem. The proposed method can be verified with 2D position of arrow that were taken by SICK Ranger-D50 laser scan camera.

지하철 무선통신설비와 주파수 공용 전화방식의 연계방안에 관한 연구 (A Study about coordinate schemes of radio and TRS(Trunked Radio System) in subway)

  • 어용;김명수;이병송
    • 한국철도학회:학술대회논문집
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    • 한국철도학회 2003년도 추계학술대회 논문집(III)
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    • pp.210-215
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    • 2003
  • At present, communication network for subway is making use of the train radio system for main network and normally established a base station every three subway station. It is talk over the telephone between a locomotive and the traffic control for careful train service. Besides, mobile telephone equipment is using for service improve and convenience to passengers such as 011, 016, 017, 019 and what not. However, the train radio system has been occurring a various problems when a state of emergency because it is able to compose only one communication route each base station zone. We could have improving like this problems through induce the TRS(Trunked Radio System), though because have been able to compose multilateral communication route in case of linking with LCX(Leaked Coaxial) cable which is established. Therefore, we could be able to a fitting meet the emergency as train firing etc.. and efficient use of limited frequency resources.

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영상처리 기술을 활용한 가상 피팅기와 머신 러닝 기술을 기반으로 한 옷 추천 서비스 (Apparel recommendation service based on image recognition over virtual fitting machine)

  • 김남훈;김동균;정재진;차재성;김웅섭
    • 한국정보처리학회:학술대회논문집
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    • 한국정보처리학회 2018년도 추계학술발표대회
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    • pp.786-789
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    • 2018
  • 우리는 가상 현실 환경에서 사람이 직접 옷을 입지 않은 상황에서 미리 피팅 상황을 확인할 수 있는 시스템을 구현하였다. 이를 위하여 우리는 시스템을 이용한 카메라 촬영과 결과를 출력하는 기능, 그리고 영상처리에서 사람 얼굴 인지, 및 그에 대한 내용을 기반으로 옷을 오버레이하는 기능을 구현하였다. 추가 기능으로는 사람 손동작 인지를 통한 커맨드 제어, 딥러닝을 이용하여 사람의 얼굴에 어울리는 옷을 추천해주는 추천 서비스를 구현하였다.

다중격자 다중차원 기법을 응용한 캠과 종동물의 비정상 상태의 유막특성 연구 (Study on the Transient EHL Fluid Film for the Dynamic Contact Behaviors between Cam and Follower with Multigrid Multilevel Method)

  • 장시열
    • Tribology and Lubricants
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    • 제20권3호
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    • pp.132-139
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    • 2004
  • Many researches about the contacts between cam and follower have investigated EHL film thickness either without dynamic loading effect or only with curve fitting formula such as Dowson-Hamrock's, because including squeeze film effect makes it hard to obtain convergence and stability of computation. Therefore, inaccurate information about minimum film thickness without dynamic loading condition causes inappropriate design of cam profiles and wrong selection of cam and follower materials. In this work, computation tools both for kinematics and dynamics of valve train system of push-rod type and for fluid film thickness with elastic deformation on the basis of dynamic loading condition with multigrid multi-level method is developed. The computational results of minimum film thickness with the respects of both static and dynamic loading conditions are compared for the contact of flat follower over the entire cycle.

새로운 파괴예측 모델을 이용한 상수도 관의 최적 교체 (Optimal Pipe Replacement Analysis with a New Pipe Break Prediction Model)

  • 박수완
    • 상하수도학회지
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    • 제16권6호
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    • pp.710-716
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    • 2002
  • A General Pipe Break Prediction Model that incorporates linear and exponential models in its form is developed. The model is capable of fitting pipe break trends that have linear, exponential or in between of linear and exponential trend by using a weighting factor. The weighting factor is adjusted to obtain a best model that minimizes the sum of squared errors of the model. The model essentially plots a best curve (or a line) passing through "cumulative number of pipe breaks" versus "break times since installation of a pipe" data points. Therefore, it prevents over-predicting future number of pipe breaks compared to the conventional exponential model. The optimal replacement time equation is derived by using the Threshold Break Rate equation by Loganathan et al. (2002).

A Study on Comparison of Upper Body Shapes and Types of Chinese Adult Women in Beijing and Shanghai - Focused on a Time-Series Analysis by Region and between Regions -

  • Sohn, Hee-Soon;Chang, Hee-Kyung
    • 패션비즈니스
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    • 제12권3호
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    • pp.72-86
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    • 2008
  • This study was aimed at providing some information about Chinese adult women's body measurements and standard body types to the Korean apparel businesses who have advanced into the Chinese apparel markets, while endeavoring to localize their businesses, and thereby, conducing to development and production of women's apparel well fitting the Chinese consumers in terms of measurements and shapes. To this end, the researchers sampled the Chinese adult women in Beijing and Shanghai aged between 19 and 20 and therewith, surveyed their upper body measurements and changes over time and thereupon, determined their standard body types.

Red Shift of the Raman (FBCARS) Excitation Profile of Iodine from the Absorption Spectrum(I)

  • Lee, Mu-Sang;Carreira, L.A.
    • Bulletin of the Korean Chemical Society
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    • 제7권1호
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    • pp.59-62
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    • 1986
  • Folded Box coherent anti-Stokes Raman spectroscopy (FBCARS) spectra of the fundamental symmetric stretch(213 $cm^{-1}$) and the first overtone(421 $cm^{-1}$) of $I_2$ have been recorded over the pump wavelength range from 495 nm to 580 nm. The lineshapes were fitted using the least squares method and the A and C term of CARS were calculated. From the fitting of A and C terms, the real(R) and imaginary(I) term intensity of CARS were calculated using harmonic oscillator program. The calculated CARS excitation profile of $I_2$ with R and I term data was about 270 $cm^{-1}$ red shifted from the absorption spectrum.