• Title/Summary/Keyword: 역행

Search Result 410, Processing Time 0.027 seconds

긴급특집-과학기술행정체제 후진은 없다

  • Jeong, Geun-Mo;Kim, Si-Jung;Lee, Gwang-Yeong
    • The Science & Technology
    • /
    • v.22 no.8 s.243
    • /
    • pp.8-18
    • /
    • 1989
  • 행정개혁위원회가 과기처 행정체제를 축소 조정키로 성안, 이를 대통령에게 보고함에 따라 과총회원단체를 중심으로 과학기술계는 동위원회의 결정방향이 경쟁적으로 과학기술정책을 강화해 나가는 세계명국의 추세에 역행하는 처사로 인식, 성명서와 건의서를 계속 발표하고 있다. 이달 긴급 특집은 과학기술정책, 기초과학 및 과학기술 전문언론인의 시각에서 이 문제의 심각성을 다루었다.

  • PDF

Signal Detection Using Wavelet Transform in Fractional Brownian Motion (Fractional Brownian Motion 잡음환경 하에서 웨이브렛 변환을 이용한 신호의 검출)

  • 김명진
    • Proceedings of the Korea Institute of Convergence Signal Processing
    • /
    • 2000.08a
    • /
    • pp.21-24
    • /
    • 2000
  • Fractional Brownian motion(fBm)은 long-term persistence 특성을 가진 자연 현상, 1/f 잡음, 깊이가 낮은 해저에서의 배경음향잡음 등을 모델링하는데 많이 사용된다. 이 fBm은 nonstationary 유색잡음이다. 이러한 유색잡음 환경 하에서 신호를 검출하기 위한 한 방법은 Fredholm 적분방정식의 해를 구하는 것이다. 이 방정식을 이산화 하면 잡음의 공분산 행렬의 역행렬이 포함되어 계산량이 많다 본 논문에서는 fBm 잡음의 공분산 행렬을 웨이브렛 변환하여 얻어지는 행렬, 즉 fBm의 멀티스케일 성분들의 공분산행렬은 밴드화된 블록들로 근사화할 수 있다는 성질을 이용하여 적은 계산량으로 신호를 검출하는 알고리즘을 제안한다.

  • PDF

Efficient Implementation and Security Analysis of Privacy-Preserving Technique based on Random Substitutions (랜덤대치 기반 프라이버시 보호 기법의 효율적인 구현 및 안전성 분석)

  • An, Aron;Kang, Ju-Sung;Hong, Dowon
    • Proceedings of the Korea Information Processing Society Conference
    • /
    • 2007.11a
    • /
    • pp.1131-1134
    • /
    • 2007
  • 본 논문에서는 랜덤대치(random substitution) 기법에 대하여 심도 있는 분석을 실시한다. 랜덤대치 기법의 효율적인 구현을 위하여 데이터 재구축(reconstruction) 과정에서 필요로 하는 역행렬을 구하는 공식을 제시한다. 또한, 랜덤대치에 사용되는 다양한 파라미터들의 의미를 실험적으로 밝혀내며, 정확도와 프라이버시를 합리적으로 측정할 수 있는 새로운 측도(measure)들을 제안한다.

Adaptive Variable Weights Tuning in an Integrated Chassis Control for Lateral Stability Enhancement (횡방향 안정성 향상을 위한 통합 섀시 제어의 적응 가변 가중치 조절)

  • Yim, Seongjin;Kim, Wooil
    • Transactions of the Korean Society of Mechanical Engineers A
    • /
    • v.40 no.1
    • /
    • pp.103-111
    • /
    • 2016
  • This paper presents an adaptive variable weights tuning system for an integrated chassis control with electronic stability control (ESC) and active front steering (AFS) for lateral stability enhancement. After calculating the control yaw moment needed to stabilize a vehicle with a controller design method, it is distributed into the tire forces generated by ESC and AFS using weighted pseudo-inverse-based control allocation (WPCA). On a low friction road, lateral stability can deteriorate due to high vehicle speed. To cope with the problem, adaptive tuning rules on variable weights of the WPCA are proposed. To check the effectiveness of the proposed method, a simulation was performed on the vehicle simulation package, CarSim.

Development of Building 3D Spatial Information Extracting System using HSI Color Model (HSI 컬러모델을 활용한 건물의 3차원 공간정보 추출시스템 개발)

  • Choi, Yun Woong;Yook, Wan Man;Cho, Gi Sung
    • Journal of Korean Society for Geospatial Information Science
    • /
    • v.21 no.4
    • /
    • pp.151-159
    • /
    • 2013
  • The building information should be up-to-date information and propagated rapidly for urban modeling, terrain analysis, life information, navigational system, and location-based services(LBS), hence the most recent and updated data of the building information have been required of researchers. This paper presents the developed system to extract the 3-dimension spatial information from aerial orthoimage and LiDAR data of HSI color model. In particular, this paper presents the image processing algorithm to extract the outline of specific buildings and generate the building polygon from the image using HIS color model, recursive backtracking algorithm and the search maze algorithm. Also, this paper shows the effectivity of the HIS color model in the image segmentation.

Determination of Weighting Factor in the Inverse Model for Estimating Surface Velocity from AVHRR/SST Data (AVHRR/SST로 부터 표층유속을 추정하기 위한 역행렬 모델에서 가중치의 설정)

  • Lee, Tae-Shin;Chung, Jong-Yul;Kang, Hyoun-Woo
    • 한국해양학회지
    • /
    • v.30 no.6
    • /
    • pp.543-549
    • /
    • 1995
  • The inverse method has been used to estimate a surface velocity field from sequential AVHRR/SST data. In the model, equation system was composed of heat equation and horizontal divergence minimization and the velocity field contained in the advective term of the heat equation, which was linearized in grid system, was estimated. A constraint was the minimization of horizontal divergence with weighting factor and introduced to compensate the null space(Menke, 1984) of the velocity solutions for the heat equation. The experiments were carried out to set up the range of weighting factor and the matrix equation was solved by SVD(Singular Value Decomposion). In the experiment, the scales of horizontal temperature gradient and divergence of synthetic velocity field were approximated to those of real field. The neglected diffusive effect and the horizontal variation of heat flux in the heat equation were regarded as random temperature errors. According to the result of experiments, the minimum of relative error was more desirable than the minimum of misfit as the criteria of setting up the weighting factor and the error of estimated velocity field became small when the weighting factor was order of $10^{-1}$

  • PDF

A Test of Hierarchical Model of Bilinguals Using Implicit and Explicit Memory Tasks (이중언어자의 위계모형 검증 : 암묵기억과제와 외현기억과제의 효과)

  • 김미라;정찬섭
    • Korean Journal of Cognitive Science
    • /
    • v.9 no.1
    • /
    • pp.47-60
    • /
    • 1998
  • The study was designed to investigate implicit and explicit memory effec representations of bilinguals. Hierarchical model of bilingual information processing word naming and translation tasks in the context of semantically categorized or rar Experiments 1 and 2, bilinguals first viewed stimulus words and performed naming or tr then implicit and explicit memory tasks. In experiment I, word recognition times(exp were significantly faster for semantic category condition than random category condi naming task and lexical decision taskOmplicit memory task)showed no difference in e experiment 2, naming task and exlicit memory task showed categorization effect but fOWE a and implcit memory task showed no categorization effect. These findings support the which posits that memory representations of bilinguals are composed of two independer a and one common conceptual store.

  • PDF

Cyclicality of Inter-Industry Wage Gaps and Segmented Labor Market Hypotheses (산업간 임금격차의 경기변동상 변화 패턴과 분단노동시장 가설)

  • Shin, Donggyun
    • Journal of Labour Economics
    • /
    • v.26 no.3
    • /
    • pp.77-114
    • /
    • 2003
  • Analyses of the special data sets constructed from the National Longitudinal Survey of Youth and the Panel Study of Income Dynamics reveal that, compared with an annual wage measure, survey week wages are significantly counter-cyclically biased due to selecting workers with strong labor market attachment. We also find that survey week wages are more counter-cyclically biased in high-wage industries than in low-wage industries, that is, inter-industry gaps of survey week wages are counter-cyclically biased. Unlike existing longitudinal studies, the current study concludes that real wages are much more procyclical in high-wage industries than in low-wage industries, which is attributed to our adoption of annual wages that is less subject to the selectivity bias. Our finding is consistent with the empirical regularity that real wages are much more procyclical for men than for women, as men are overrepresented in industries with greater real wage procyclicalities. Overall, current results do not support the predictions of segmented labor market theories for the cyclicality of real wages.

  • PDF

Improving the Performance of the Capon Algorithm by Nulling Elements of an Inverse Covariance Matrix (공분산 역행렬 원소 제거 기법을 이용한 Capon 알고리듬의 성능 개선)

  • Kim, Seong-Min;Kang, Dong-Hoon;Lee, Yong-Wook;Nah, Sun-Phil;Oh, Wang-Rok
    • Journal of the Institute of Electronics Engineers of Korea SP
    • /
    • v.48 no.5
    • /
    • pp.96-101
    • /
    • 2011
  • It is well known that the Capon algorithm offers better resolution compared to that of the FM (Fourier method) algorithm by minimizing the total output power while maintaining a constant gain in the look direction. Unfortunately, the DoA (Direction of Arrival) estimation performance of the Capon algorithm is drastically degraded when the SNR of received signal is low and thus, it cannot distinguish among signal sources which have similar incidence angles. In this paper, we propose a novel scheme enhancing the resolution of the Capon algorithm by ing all rows except the first row of an inverse covariance matrix.