• 제목/요약/키워드: Selection Bias

검색결과 331건 처리시간 0.025초

Simulation of Domain Growth in Antiferroelctric Liquid Crystal Display

  • Jhun, Chul-Gyu;Ann, Sun-Mo;Moon, Sung-O;Lee, Gi-Dong;Yoon, Tae-Hoon;Kim, Jae-Chang
    • 한국정보디스플레이학회:학술대회논문집
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    • 한국정보디스플레이학회 2003년도 International Meeting on Information Display
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    • pp.581-584
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    • 2003
  • Most modeling about dynamic behavior of Antiferroelectric Liquid Crystal (AFLC) is limited to the hysteric characteristics of AFLC cells or thresholdless switching of frustrated AFLC cells. In this paper, domain growth of AFLC cells is modeled with extended bilayer model. When driving pulses that consist of a selection voltage, a bias voltage, and a reset voltage are applied to the AFLC cell, its dynamic behavior is simulated.

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비휘발성 단일트랜지스터 강유전체 메모리 회로 (Memory Circuit of Nonvolatile Single Transistor Ferroelectric Field Effect Transistor)

  • 양일석;유병곤;유인규;이원재
    • 대한전자공학회:학술대회논문집
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    • 대한전자공학회 2000년도 추계종합학술대회 논문집(2)
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    • pp.55-58
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    • 2000
  • This paper describes a single transistor type ferroelectric field effect transistor (1T FeFET) memory celt scheme which can select one unit memory cell and program/read it. To solve the selection problem of 1T FeEET memory cell array, the row direction common well is electrically isolated from different adjacent row direction column. So, we can control voltage of common well line. By applying bias voltage to Gate and Well, respectively, we can implant IT FeEET memory cell scheme which no interface problem and can bit operation. The results of HSPICE simulations showed the successful operations of the proposed cell scheme.

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THE GALAXY-BLACK HOLE CONNECTION IN THE LOCAL UNIVERSE

  • Schawinski, Kevin;Fellow, Einstein
    • 천문학논총
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    • 제25권3호
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    • pp.77-82
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    • 2010
  • Recent results from large surveys of the local universe show that the galaxy-black hole connection is linked to host morphology at a fundamental level and that there are two fundamentally different modes of black hole growth. The fraction of early-type galaxies with actively growing black holes, and therefore the AGN duty cycle, declines significantly with increasing black hole mass. Late-type galaxies exhibit the opposite trend: the fraction of actively growing black holes increases with black hole mass. Issues of AGN selection bias and prospects for near-future efforts with high redshift data are discussed.

A Single Transistor Type Ferroelectric Field-Effect-Transistor Cell Scheme

  • Yang, Yil-Suk;You, In-Kyu;Lee, Wong-Jae;Yu, Byoung-Gon;Cho, Kyong-Ik
    • 대한전자공학회:학술대회논문집
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    • 대한전자공학회 2000년도 ITC-CSCC -1
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    • pp.403-405
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    • 2000
  • This paper describes a single transistor type ferroelectric field effect transistor (1Tr FeFET) memory cell scheme, which select one unit memory cell and program/read it. The well voltage can be controlled by isolating the common row well lines. Through applying bias voltage to Gate and Well, respectively, we implement If FeFET memory cell scheme in which interference problem is not generated and the selection of each memory cell is possible. The results of HSPICE simulations showed the successful operations of the proposed cell scheme.

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PcMeter를 이용한 인터넷 접속을 측정 (Korean internet audience centric measurement : Internet index)

  • 이상경
    • 한국조사연구학회지:조사연구
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    • 제1권1호
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    • pp.125-134
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    • 2000
  • 인터넷 리서치의 과학성을 담보하기 위해서는 과학적 원칙과 절차를 지켜야 한다. 그 핵심은 표본추출에 있으며, 특히 자기선택오류를 범하지 않기 위한 방안이 모색되어야 한다. 먼저 인터넷센서스를 통해 네티즌의 분포와 변화상황를 주기적으로 체크하고 그에 준한 표본추출을 실시하여 패널을 구축한다. 구축된 패널에 PcMeter 를 장착케 하여 전송된 로그를 분석하여 제시하는 이를 인터넷 인덱스라한다.

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Fast Training of Structured SVM Using Fixed-Threshold Sequential Minimal Optimization

  • Lee, Chang-Ki;Jang, Myung-Gil
    • ETRI Journal
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    • 제31권2호
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    • pp.121-128
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    • 2009
  • In this paper, we describe a fixed-threshold sequential minimal optimization (FSMO) for structured SVM problems. FSMO is conceptually simple, easy to implement, and faster than the standard support vector machine (SVM) training algorithms for structured SVM problems. Because FSMO uses the fact that the formulation of structured SVM has no bias (that is, the threshold b is fixed at zero), FSMO breaks down the quadratic programming (QP) problems of structured SVM into a series of smallest QP problems, each involving only one variable. By involving only one variable, FSMO is advantageous in that each QP sub-problem does not need subset selection. For the various test sets, FSMO is as accurate as an existing structured SVM implementation (SVM-Struct) but is much faster on large data sets. The training time of FSMO empirically scales between O(n) and O($n^{1.2}$), while SVM-Struct scales between O($n^{1.5}$) and O($n^{1.8}$).

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이차 평활스플라인 (A Second Order Smoother)

  • 김종태
    • 응용통계연구
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    • 제11권2호
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    • pp.363-376
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    • 1998
  • 선형 평활스플라인 추정은 경계 편의의 영향력을 제거 하기위해 수정된 것이다. 제시된 추정량은 적합된 값들과 관련있는 평활 모수 선택 기준의 계산을 개선시킨 O(n) 얄고리즘을 사용하여 효과적으로 계산할 수 있게 하였다. 추정량의 점근적 성질들이 균일 계획의 경우에 대하여 연구되었다. 이 경우에 경계수정 선형 평활스플라인들의 평균 제곱 오차의 성질들은 표준 이차 커널 평활들에 대한 평균제곱오차들과 점근적 특성으로 비교하였다.

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Low-Power CMOS image sensor with multi-column-parallel SAR ADC

  • Hyun, Jang-Su;Kim, Hyeon-June
    • 센서학회지
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    • 제30권4호
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    • pp.223-228
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    • 2021
  • This work presents a low-power CMOS image sensor (CIS) with a multi-column-parallel (MCP) readout structure while focusing on improving its performance compared to previous works. A delta readout scheme that utilizes the image characteristics is optimized for the MCP readout structure. By simply alternating the MCP readout direction for each row selection, additional memory for the row-to-row delta readout is not required, resulting in a reduced area of occupation compared to the previous work. In addition, the bias current of a pre-amplifier in a successive approximate register (SAR) analog-to-digital converter (ADC) changes according to the operating period to improve the power efficiency. The prototype CIS chip was fabricated using a 0.18-㎛ CMOS process. A 160 × 120 pixel array with 4.4 ㎛ pitch was implemented with a 10-bit SAR ADC. The prototype CIS demonstrated a frame rate of 120 fps with a total power consumption of 1.92 mW.

자가소유가 복지인식에 미치는 영향 (The Effects of Homeownership on Welfare Perceptions)

  • 백종규
    • 한국산업융합학회 논문집
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    • 제25권6_3호
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    • pp.1261-1273
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    • 2022
  • Homeownership is much more than a financial calculation. It is a socio-psychological phenomenon. During the last decade studies of homeownership have demonstrated a positive link between homeownership and positive social outcomes including welfare perceptions and attitudes. This study compared welfare perceptions between homeowners and renters in Korean Welfare Panel Survey using data collected in 2019. The study analyzed six continuous outcomes of welfare perceptions. Six variables indicating welfare perceptions included: (1) welfare and work disincentives; (2) welfare recipients are lazy; (3) welfare selectivism; (4) national minimum; (5) free university education and; (6) free child care and kindergarten. This study acknowledged bias arising from selection on observables. To control these biases, this study employed analytical approaches including the treatment effect model. Results of this study confirmed that attainment of homeownership is not possible for everyone. Findings from this study have provided some evidence that homeowners and renters have different perceptions on welfare listed above. Finally, issues relating to homeownership and welfare perceptions were discussed. Implications for social work practice and research were further discussed.

농업부문 기후시나리오 활용의 주의점 (The Use and Abuse of Climate Scenarios in Agriculture)

  • 김진희;윤진일
    • 한국농림기상학회지
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    • 제18권3호
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    • pp.170-178
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    • 2016
  • 농업부문의 기후변화 적응은 농작물의 생육과 수량에 미치는 기후변화 영향의 정량평가로부터 시작된다. 이를 위한 조건으로서 작물모형 외에 과거-미래 간 이음새 없는 기후자료가 필요하지만, 기후시나리오에서 산출된 과거 기간의 자료는 실측 기후와 차이가 난다. 이것을 보정 없이 작물모형 구동에 사용한다면 농작물의 생육과 수량예측이 현실과 동떨어진 것이 되어 모의결과를 바탕으로 마련된 적응대책은 실효성이 낮아진다. 또한 동일한 기후시나리오를 사용자에 따라 서로 다른 시공간적 상세화 작업이나 기후모델의 편의보정을 위한 후처리 작업을 수행한다면 작물모형 구동결과는 달라질 수 있다. 농업부문에서 불확실성을 최소화한 영향평가결과를 도출하기 위해서는 먼저 최종 사용자의 목적에 적합한 공간적 및 시간적 규모를 설정하는 일이다. 나아가 과거기후의 재현성을 포함한 시나리오기후의 불확실성을 정확히 파악하여 영향평가결과의 불확실성을 정량적으로 제시할 수 있어야 한다. 이 논문에서는 기후시나리오의 농업분야 활용과정에서 발생할 수 있는 불확실성을 요인별로 추적하고, 이를 줄이기 위한 자료처리기법을 소개하며, 연구목적에 따른 최적 시나리오 자료를 추천함으로써 기후변화 적응을 위한 기초정보를 제공하고자 하였다.