• 제목/요약/키워드: projection operator

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SELF-ADJOINT INTERPOLATION ON Ax = y IN ALG$\cal{L}$

  • Kwak, Sung-Kon;Kang, Joo-Ho
    • Journal of applied mathematics & informatics
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    • 제29권3_4호
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    • pp.981-986
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    • 2011
  • Given vectors x and y in a Hilbert space $\cal{H}$, an interpolating operator is a bounded operator T such that Tx = y. An interpolating operator for n vectors satisfies the equations $Tx_i=y_i$, for i = 1, 2, ${\cdots}$, n. In this paper the following is proved : Let $\cal{L}$ be a subspace lattice on a Hilbert space $\cal{H}$. Let x and y be vectors in $\cal{H}$ and let $P_x$ be the projection onto sp(x). If $P_xE=EP_x$ for each $E{\in}\cal{L}$, then the following are equivalent. (1) There exists an operator A in Alg$\cal{L}$ such that Ax = y, Af = 0 for all f in $sp(x)^{\perp}$ and $A=A^*$. (2) sup $sup\;\{\frac{{\parallel}E^{\perp}y{\parallel}}{{\parallel}E^{\perp}x{\parallel}}\;:\;E\;{\in}\;{\cal{L}}\}$ < ${\infty}$, $y\;{\in}\;sp(x)$ and < x, y >=< y, x >.

Unbounded Scalar Operators on Banach Lattices

  • deLaubenfels, Ralph
    • 호남수학학술지
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    • 제8권1호
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    • pp.1-19
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    • 1986
  • We show that a (possibly unbounded) linear operator, T, is scalar on the real line (spectral operator of scalar type, with real spectrum) if and only if (iT) generates a uniformly bounded semigroup and $(1-iT)(1+iT)^{-1}$ is scalar on the unit circle. T is scalar on [0, $\infty$) if and only if T generates a uniformly bounded semigroup and $(1+T)^{-1}$ is scalar on [0,1). By analogy with these results, we define $C^0$-scalar, on the real line, or [0. $\infty$), for an unbounded operator. We show that a generator of a positive-definite group is $C^0$-scalar on the real line. and a generator of a completely monotone semigroup is $C^0$-scalar on [0, $\infty$). We give sufficient conditions for a closed operator, T, to generate a positive-definite group: the sequence < $\phi(T^{n}x)$ > $_{n=0}^{\infty}$ must equal the moments of a positive measure on the real line, for sufficiently many positive $\phi$ in $X^{*}$, x in X. If the measures are supported on [0, $\infty$), then T generates a completely monotone semigroup. On a reflexive Banach lattice, these conditions are also necessary, and are equivalent to T being scalar, with positive projection-valued measure. T generates a completely monotone semigroup if and only if T is positive and m-dispersive and generates a bounded holomorphic semigroup.

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EZW를 이용한 POCS 기반의 후처리 기법 (Post-processing Technique Based on POCS Using EZW)

  • 김효각;권구락;김윤;고성제
    • 대한전자공학회:학술대회논문집
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    • 대한전자공학회 2005년도 추계종합학술대회
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    • pp.427-430
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    • 2005
  • In this paper, we propose a new post-processing method, based on the theory of the projection onto convex sets (POCS) to reduce the blocking artifacts in decoded images. We propose a new smoothness constraint set (SCS) and its projection operator in the wavelet transform (WT) domain to remove unnecessary high-frequency components caused by blocking artifacts. We also propose a new method to find and preserve the original high frequency components of the image edge. Experimental results show that the proposed method can not only achieve a significantly enhanced subjective quality, but also have the PSNR improvement in the output image.

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On Negative Imperatives in Korean

  • Han, Chung-hye;Lee, Chung-min
    • 한국언어정보학회:학술대회논문집
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    • 한국언어정보학회 2002년도 Language, Information, and Computation Proceedings of The 16th Pacific Asia Conference
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    • pp.59-68
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    • 2002
  • In this paper, we address two questions concerning negative imperatives in Korean: (i) what is the morpho-syntactic nature of mal in negative imperatives\ulcorner; and (ii) why is it impossible to form negative imperatives with short negation an\ulcorner We will argue that the clause structure of imperatives include a projection of deontic modality and a projection of imperative operator encoding illocutionary force, and that oaf is a lexicalization of long negation and deontic modality. We then propose that a negative imperative with short negation is ruled out because such construction maps onto incoherent interpretation which can be spelled out as I direct you to bring about a negative state or a negative event.

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Numerical Simulation of Laminar Reacting Flows Using Unstructured Finite Volume Method With Adaptive Refinement

  • Kang, Sung-Mo;Kim, Hoo-Joong;Kim, Yong-Mo
    • 한국연소학회지
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    • 제6권2호
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    • pp.15-22
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    • 2001
  • A pressure-based, unstructured finite volume method has been applied to couple the chemical kinetics and fluid dynamics and to capture effectively and accurately the steep gradient flame field. The pressure-velocity coupling is handled by two methodologies including the pressure-correction algorithm and the projection scheme. A stiff, operator-split projection scheme for the detailed nonequilibrium chemistry has been employed to treat the stiff reaction source terms. The conservative form of the governing equations are integrated over a cell-centered control volume with collocated storage for all transport variables. Computations using detailed chemistry and variable transport properties were performed for two laminar reacting flows: a counterflow hydrogen-air diffusion flame and a lifted methane-air triple flame. Numerical results favorably agree with measurements in terms of the detailed flame structure.

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어린이 통학버스의 로드 프로젝션 등화장치 표준 제정에 관한 연구 (A Study on the Establishment of a Standard for Road Projection Lighting Devices for School Buses)

  • 신판주;김재철;김현
    • 자동차안전학회지
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    • 제15권3호
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    • pp.43-52
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    • 2023
  • When a children's school bus stops on the road, the operator enables an amber flashing light (indicating stopping or slowing) or a red flashing light (indicating that children are getting on and off). Drivers of vehicles passing by the stopped school bus, as well as vehicles in adjacent lanes to the school bus must stop temporarily. However, many drivers are not aware of the laws and do not comply with them, so children are exposed to an increased risk of being hit, especially at night as the color recognition of the vehicle is significantly lower than during the day. In our experiments, messages and shapes using light were projected to the front and rear of a parked school bus, in addition to its red lights flashing.

PARALLEL SHRINKING PROJECTION METHOD FOR FIXED POINT AND GENERALIZED EQUILIBRIUM PROBLEMS ON HADAMARD MANIFOLD

  • Hammed Anuoluwapo Abass;Olawale Kazeem Oyewole
    • 대한수학회논문집
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    • 제39권2호
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    • pp.421-436
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    • 2024
  • In this article, we propose a shrinking projection algorithm for solving a finite family of generalized equilibrium problem which is also a fixed point of a nonexpansive mapping in the setting of Hadamard manifolds. Under some mild conditions, we prove that the sequence generated by the proposed algorithm converges to a common solution of a finite family of generalized equilibrium problem and fixed point problem of a nonexpansive mapping. Lastly, we present some numerical examples to illustrate the performance of our iterative method. Our results extends and improve many related results on generalized equilibrium problem from linear spaces to Hadamard manifolds. The result discuss in this article extends and complements many related results in the literature.

DERIVATIONS ON CR MANIFOLDS

  • Ryu, Jeong-Seog;Yi, Seung-Hun
    • 대한수학회논문집
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    • 제19권1호
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    • pp.135-141
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    • 2004
  • We studied the relation between the tangential Cauchy-Riemann operator ${\={\partial}}_b$ CR-manifolds and the derivation $d^{{\pi}^{0,\;1}}$ associated to the natural projection map ${\pi}^{0.1}\;:\;TM\;{\bigotimes}\;{\mathbb{C}}\;=\;T^{1,0}\;{\bigoplus}\;T^{0,\;1}\;{\rightarrow}\;T^{0,\;1}$. We found that these two differential operators agree only on the space of functions ${\Omega}^0(M),\;unless\;T^{1,\;0}$ is involutive as well. We showed that the difference is a derivation, which vanishes on ${\Omega}^0(M)$, and it is induced by the Nijenhuis tensor associated to ${\pi}^{0.1}$.

디지털 영상에서 부화소 정밀도의 실제 경계 추정 (Estimation of Real Boundary with Subpixel Accuracy in Digital Imagery)

  • 김태현;문영식;한창수
    • 한국정밀공학회지
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    • 제16권8호
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    • pp.16-22
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    • 1999
  • In this paper, an efficient algorithm for estimating real edge locations to subpixel values is described. Digital images are acquired by projection into image plane and sampling process. However, most of real edge locations are lost in this process, which causes low measurement accuracy. For accurate measurement, we propose an algorithm which estimates the real boundary between two adjacent pixels in digital imagery, with subpixel accuracy. We first define 1D edge operator based on the moment invariant. To extend it to 2D data, the edge orientation of each pixel is estimated by the LSE(Least Squares Error)line/circle fitting of a set of pixels around edge boundary. Then, using the pixels along the line perpendicular to the estimated edge orientation the real boundary is calculated with subpixel accuracy. Experimental results using real images show that the proposed method is robust in local noise, while maintaining low measurement error.

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상황인식에 대한 측정 및 차세대 원자로 운전원 성능 평가에서의 활용방법에 관한 이론 연구 (A Review on Measurement and Applications of Situation Awareness for an Evaluation of Korea Next Generation Reactor Operator Performance)

  • 이동하;이현철
    • 산업공학
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    • 제13권4호
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    • pp.751-758
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    • 2000
  • Situation awareness is defined as a person's perception of the elements of the environment within a volume of time and space, the comprehension of their meaning and the projection of their status in the near future. Situation awareness is important in attempting to evaluate human behavior in operating complex systems such as aircraft, air traffic control, and nuclear power plant systems. From the literatures this study reviews the relationship between situation awareness and numerous individual, system and environmental factors, and also reviews the methodologies for the empirical measurement of situation awareness applicable to Korea Next Generation Reactor (KNGR) design project. Attention, working memory, workload, stress, system complexity, and automation are presented as critical factors limiting operator's situation awareness. Mental models and goal-directed behavior are hypothesized as important mechanisms overcoming these limits. This study summarized hypothesized guidelines for interface design to improve situation awareness of reactor operators. Some of the guidelines should be tested in the KNGR evaluation experiments in the future.

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