• 제목/요약/키워드: Concept drift

검색결과 78건 처리시간 0.026초

전진적 단계 알고리즘을 이용한 대용량 데이터와 순차적 배치 데이터의 분류 (Classification of large-scale data and data batch stream with forward stagewise algorithm)

  • 윤영주
    • Journal of the Korean Data and Information Science Society
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    • 제25권6호
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    • pp.1283-1291
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    • 2014
  • 본 논문에서는 대용량이거나 시간에 따라 순차적으로 들어오는 데이터의 분류를 위한 전진적 단계 알고리즘을 제안한다. Adaboost 알고리즘은 노이즈가 있는 데이터에 대하여 성능이 떨어지는 것으로 알려져 있다. 이를 해결하기 위한 한 가지 방법으로 전진적 단계 선형 회귀 방법을 사용한다. 대용량 데이터나 순차적 배치 데이터의 경우에도 이러한 상황을 극복하기 위해 전진적 단계 알고리즘 방법을 적용한 방법을 제안한다. 모의실험과 실제 자료 분석을 통해 제안된 알고리즘이 좋은 성능을 보임을 알 수 있었다.

『황제내경(黃帝內經)』의 침구법(鍼灸法) 연구 - 시간(時間) 개념을 중심으로 - (A Study on the Acupuncture & Moxibustion of Huangdineijing - focused on Concept of Time -)

  • 류정아
    • 대한한의학원전학회지
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    • 제29권3호
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    • pp.57-74
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    • 2016
  • Subject : Treatment of acupuncture & moxibustion in Huangdineijing Objectives : Discover the principles and substances of acupuncture & moxibustion treatment of Huangdineijing Methods : The author reviewed the Huangdineijing: Suwen, Lingshu to gain a realistic sense of the facts and the medical book's contents that deal with the practices of acupuncture & moxibustion treatment for clinical praxis. Conclusions : 1. The acupuncture & moxibustion of Huangdineijing can be defined as follows. A treatment for correcting of meridian's drift by proper selection of surgical site, using suitable implementation and appropriate manipulation skill from a correct judgement of meridian's flowing through sensing the pulse for diagnosis when the meridian's flowing which come and go constantly driven by the tidal order of defensive Qi tactually appeared hard or soft caused by diseases, thus bring out the soft & gradual 50 laps circulation of nutrient Qi moderately driven by defensive Qi. 2. Today's acupuncture & moxibustion treatments greatly differ from those of Huangdineijing in that we do not know the substance of that treatment which is correcting of meridian's drift and do not obligatorily carry out feeling of the pulse for diagnosis which is a measure & judgement of meridian's flowing against a preliminary treatment in parallel with treatment so reduce use and power of that treatment. 3. I could form a list of general principle from the substances of acupuncture & moxibustion of Huangdineijing like as the flowing or fate of meridian Qi(tidally going in order of defensive Qi and nutrient Qi), deficiency or excess of Meridian flowing, comparing diagnosis before and after treatment, bring out the soft & gradual Qi. That was imposing "the concept of time" on recognition and treatment to human body.

상, 하악 제1소구치 발치 후 하악치열의 생리적 치아이동에 관한 연구 (PHYSIOLOGIC DRIFT OF THE MANDIBULAR DENTITION FOLLOWING THE EXTRACTION OF FOUR FIRST PREMOLARS)

  • 전윤식
    • 대한치과교정학회지
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    • 제26권1호
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    • pp.33-41
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    • 1996
  • 소구치 발치 직후 일정기간 동안 고정식 장치를 이용한 치료를 의도적으로 연기함으로써 의외의 좋은 결과를 얻었다는 연구결과가 발표되었고 이러한 연구결과를 입증하는 임상경험을 교정의들도 가끔 하게 된다. 소구치 발치 후 하악치열의 생리적 치아이동현상을 연구한 논문에 의하면 이를 생리적 치아이동(driftodontics)이라 명명하였다. Driftodontics의 개념이 교정학 영역에서 조심스럽게 소개되고 있는 이유는 driftodontics의 성질과 이동되는 양에 대해서는 아직 조사가 미흡한 실정이며 이러한 치아이동을 이용하기 위한 지침서가 거의 소개되어있지 않기 때문이다. 따라서 본 연구의 대상은 제 I급 부정교합자 중 이전에 교정치료를 받은 경험이 없고, 상, 하악 치열궁에 crowding이 있어 상, 하악 제1소구치를 발치하기로 한 57명 (남자 16명, 여자 41명)을 대상으로 하였다. 연령에 따라 두 군으로 나누어 제1군은 26명으로, 평균연령은 13.5세(12.7-14.9세)였으며 제2군은 31명의 환자로 평균연령 21.3(18-22.1)세였다. 두 군 모두에서 소구치 발치 후 약7개월 정도의 driftodontics기간을 유지한 후 측모 두부방사선사진 및 석고모형 계측을 통하여 얻어진 결과는 다음과 같다. 1. 2군(18세-22세)에서는 주로 하악 전치 및 견치의 후방이동이 일어났으며 하악구치는 상대적으로 이동이 미약한 정도로 나타났다. 2. 1군(12세-15세)에서는 전치부 변화 비율이 2군에 비해 더욱 많이 일어났으며, 구치변화는 2군과 유사한 것으로 나타났지만 그 양은 조금 컸다. 3. 하악 전치부의 생리적 이동으로 불규칙지수(irregularity index)가 감소하고 crowding양이 감소하였다.

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OPTIMIZED NUMERICAL ANNULAR FLOW DRYOUT MODEL USING THE DRIFT-FLUX MODEL IN TUBE GEOMETRY

  • Chun, Ji-Han;Lee, Un-Chul
    • Nuclear Engineering and Technology
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    • 제40권5호
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    • pp.387-396
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    • 2008
  • Many experimental analyses for annular film dryouts, which is one of the Critical Heat Flux (CHF) mechanisms, have been performed because of their importance. Numerical approaches must also be developed in order to assess the results from experiments and to perform pre-tests before experiments. Various thermal-hydraulic codes, such as RELAP, COBRATF, MARS, etc., have been used in the assessment of the results of dryout experiments and in experimental pre-tests. These thermal-hydraulic codes are general tools intended for the analysis of various phenomena that could appear in nuclear power plants, and many models applying these codes are unnecessarily complex for the focused analysis of dryout phenomena alone. In this study, a numerical model was developed for annular film dryout using the drift-flux model from uniform heated tube geometry. Several candidates of models that strongly affect dryout, such as the entrainment model, deposition model, and the criterion for the dryout point model, were tested as candidates for inclusion in an optimized annular film dryout model. The optimized model was developed by adopting the best combination of these candidate models, as determined through comparison with experimental data. This optimized model showed reasonable results, which were better than those of MARS code.

감도해석기법을 이용한 전단벽 구조물의 최적변위제어 (Optimal Displacement Control of Shear Wall Structure using Sensitivity Analysis Technique)

  • 이한주;정성진;김호수
    • 한국전산구조공학회:학술대회논문집
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    • 한국전산구조공학회 2005년도 춘계 학술발표회 논문집
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    • pp.121-128
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    • 2005
  • This study presents an effective stiffness-based optimal technique to control quantitatively lateral drift for shear wall structures subject to lateral loads. To this end the displacement sensitivity depending on behavior characteristics of shear wall structures is established. Also, the approximation concept that can preserve the generality of the mathematical programming and can efficiently solve large scale problems is introduced. Resizing sections in the stiffness-based optimal design are assumed to be uniformly varying in size and the technique of member grouping is considered for the improvement of construction efficiency Two types of 11-story shear wall structures are presented to illustrate the features of the quantitative lateral drift control technique proposed in this study.

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Hyperbolicity Breaking Model and Drift-Flux Model for the Prediction of Flow Regime Transition after Inverted Annular Flow

  • Jeong, Hae-Yong;No, Hee-Cheon
    • 한국원자력학회:학술대회논문집
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    • 한국원자력학회 1995년도 추계학술발표회논문집(1)
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    • pp.456-461
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    • 1995
  • The concept of hyperbolicity breaking is applied to predict the flow regime transition from inverted annular flow (IAF) to agitated inverted annular flow (AIAF). The resultant correlation has the similar form to Takenaka's empirical one. To validate the proposed model, it is applied to predict Takenaka's experimental results using R-113 refrigerant with four different tube diameters of 3, 5, 7 and 10 mm. The proposed model gives accurate predictions for the tube diameters of 7 and 10 min. As the tube diameter decreases, the differences between the predictions and the experimental results increase slightly. The flow regime transition from AIAF to dispersed flow (DF) is described by the drift flux model.

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단일계수적응을 통한 강건한 적응제어시의 설계및 안정성 해석 (Robust adaptive control by single parameter adaptation and the stability analysis)

  • 오준호
    • 대한기계학회논문집
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    • 제14권2호
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    • pp.331-338
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    • 1990
  • In adaptive control, the lack of persistent and rich excitation causes the estimated parameters to drift, which degrade the performance of the system and may introduces instability to the system in a stochastic environment. To solve the problem of the parameter drift, the concept of single parameter adaptation is presented. For the parameter identification, a priori error is directly used for adaptation error. The structure of the controller is based upon the minimum variance control technique. The stability and robustness analysis is carried out by the sector stability theorem for the second order system. The computer simulation is performed to justify the theoretical analysis for the various cases.

AVC 잉여슬라이스를 이용한 DMB 비디오 스트림의 오류내성부호화 (Error resilience video coding of DMB video stream using AVC redundant slice)

  • 홍성훈;백선혜;나남웅
    • 한국정보처리학회:학술대회논문집
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    • 한국정보처리학회 2004년도 춘계학술발표대회
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    • pp.707-710
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    • 2004
  • In the case of terrestrial DMB(Digital Multimedia Broadcasting) system that offers mobile multimedia broadcasting services, transmission error must be considered. Although DMB transmission system provides the error protection functions of convolution coding and Reed-Solomon (204,188,t=8) coding, additional error resilience video coding methods are needed to satisfy the requirement of BER lower than $10^{-8}$. In this thesis, we propose and evaluate effective error resilience coding schemes using the MPEG-4 redundant slice for MPEG-4 video services in the DMB environment. In this scheme, we analyze the drift error caused by transmission error based on the random noise concept and the redundant slice selection algorithm that selects the most influential slice in the view of the drift error increment.

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가구디자인 형태창출에 있어서 비정형에 관한 연구 (A Study on A-formal in Furniture Design Form Creation)

  • 김영호
    • 한국가구학회지
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    • 제26권4호
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    • pp.301-313
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    • 2015
  • This study purposes on continuing experimental research of furniture form creation focused on the importance and necessity for a-formal concept for designers to drift away from general acknowledgement and practice routine to design more radical forms for meeting various needs of late industrialized society, which have not been satisfied with formal and universal designs. This study covers presenting new points of view on research for designers to look for different solutions to widen their consideration in the process of furniture form development and to set up academic data base with the case studies of designers in anti-construction concept to define their experimental challenges for new design form creation, on the basis of overall research on the effects and roles of a-formal approach in the furniture design form creation.

학습된 머신러닝의 표류 현상에 관한 고찰 (A Study on Drift Phenomenon of Trained ML)

  • 신병춘;차윤석;김채윤;차병래
    • 스마트미디어저널
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    • 제11권7호
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    • pp.61-69
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    • 2022
  • 학습된 머신러닝은 시간 경과에 따른 학습 모델과 학습 데이터 측면의 표류 현상이 발생과 동시에 머신러닝의 성능이 퇴화하게 된다. 이를 해결하기 위한 방안으로 머신러닝의 재학습 시기를 결정하기 위한 ML 표류의 개념과 평가 방법을 제안하고자 한다. 딸기와 선명도에 따른 XAI 테스트 및 사과 이미지의 XAI 테스트를 진행하였다. 딸기의 경우 선명도 값에 따른 ML 모델의 XAI 분석의 변화는 미미하였으며 사과 이미지의 XAI의 경우 사과는 정상적으로 객체 분류 및 히트맵 영역을 표시하였으나 사과꽃 및 꽃봉오리의 경우 그 결과가 딸기나 사과에 비해 미미하였다. 이는 사과꽃 및 꽃봉오리의 학습 이미지 수가 부족하기에 발생한 것으로 예상되며 추후 더 많은 사과꽃 및 꽃봉오리 이미지를 학습하여 테스트할 계획이다.