• 대한수학회지
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• 제41권1호
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• pp.1-20
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• 2004

Let A be a uniform algebra, and let $\phi$ be a self-map of the spectrum $M_A$ of A that induces a composition operator $C_{\phi}$, on A. It is shown that the image of $M_A$ under some iterate ${\phi}^n$ of \phi is hyperbolically bounded if and only if \phi has a finite number of attracting cycles to which the iterates of $\phi$ converge. On the other hand, the image of the spectrum of A under $\phi$ is not hyperbolically bounded if and only if there is a subspace of $A^{**}$ "almost" isometric to ${\ell}_{\infty}$ on which ${C_{\phi}}^{**}$ "almost" an isometry. A corollary of these characterizations is that if $C_{\phi}$ is weakly compact, and if the spectrum of A is connected, then $\phi$ has a unique fixed point, to which the iterates of $\phi$ converge. The corresponding theorem for compact composition operators was proved in 1980 by H. Kamowitz [17].

• 한국산업정보학회논문지
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• 제5권1호
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• pp.1-15
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• 2000

In this paper, an efficient system for finding answers to a given path algebra expression in a directed acylic graph is discussed more particulary, in a multimedia presentration graph. Path algebra expressions are formulated using revised versions of operators next and until of temporal logic, and the connected operator. To evaluate queries with path algebra expressions, the node code system is proposed. In the node code system, the nodes of a presentation graph are assigned binary codes (node codes) that are used to represent nodes and paths in a presentation graph. Using node codes makes it easy to find parent-child predecessor-sucessor relationships between nodes. A pair of node codes for connected nodes uniquely identifies a path, and allows efficient set-at-a-time evaluations of path algebra expressions. In this paper, the node code representation of nodes and paths in multimedia presentation graphs are provided. The efficient algorithms for the evaluation of queries with path algebra expressions are also provided.

• 한국전자통신학회논문지
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• 제10권7호
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• pp.813-818
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• 2015

사물 인터넷(IoT)은 물리적 객체나 전자 제품, 소프트웨어, 센서 및 제조업체, 운영자 또는 연결된 다른 장치와 데이터를 교환하여 더 큰 가치와 서비스를 달성 할 수 있도록 연결된 사물 네트워크를 말한다. 지금까지 계량 정보 분석과 미래 유망영역 탐지에 대한 연구는 키워드를 중심으로 수행해왔다. 본 논문에서는 문헌에서 키워드 매핑에 대한 동태적 분석을 통하여 최근에 관심 영역인 사물 인터넷에 대한 미래 유망 영역을 탐지하는 방법을 제시한다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 ITC-CSCC -1
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• pp.493-496
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• 2000

We study the problem of designing at minimum cost a two-connected network topology such that the shortest cycle to which each edge belongs does not exceed a given maximum number of hops. This problem is considered as part of network planning and arises in the design of backbone networks. We propose a genetic algorithm approach that uses a solution representation, in which the connectivity and ring constraints can be easily encoded. We also propose a crossover operator that ensures a generated solution is feasible. By doing so, the checking of constraints is avoided and no repair mechanism is required. We carry out experimental evaluations to investigate the solution representation issues and GA operators for the network design problem.

• East Asian mathematical journal
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• 제27권1호
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• pp.51-65
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• 2011

In the paper, we study questions on classical solvability of nonlocal problems for a third-order linear hyperbolic equation in a rectangular domain. The Riemann method is applied to the Goursat problem and solution is obtained in the integral form. Investigated problems are reduced to the uniquely solvable Volterra-type equation of second kind. Influence effects of coefficients at lowest derivatives on correctness of studied problems are detected.

• 대한수학회보
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• 제25권2호
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• pp.171-174
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• 1988

Let M be an n-dimensional compact connected and oriented Riemannian manifold isometrically immersed in an (n+2)-dimensional Euclidean space $R^{n+2}$. Moore [5] proved that if M is of positive curvature, then M is a homotopy sphere. This result is generalized by Baldin and Mercuri [2], Baik and Shin [1] to the case of non-negative curvature, which is stated as follows: If M of non-negative curvature, then M is either a homotopy sphere or diffeomorphic to a product of two spheres. In particular, if there is a point at which the curvature operator is positive, then M is homeomorphic to a sphere.e.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1998년도 하계종합학술대회논문집
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• pp.769-772
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• 1998

This paper present an efficient techniques for visual inspection of taped electronic parts, suitable for real time implementation. The main environments of developed system are IBM-compatible personal computer, frame grabber, digital input-output board. It is connected to the programmable logic controller unit of the taping machine in real time. Using a queuing structure, operator or extractor machine can remove easily the defect one from production line. Also, we design a new illumination system for sacquring shape and subface features of object. Therefore, it redue pre-processing step and processing time.

• 융합신호처리학회 학술대회논문집
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• 한국신호처리시스템학회 2003년도 하계학술대회 논문집
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• pp.161-164
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• 2003

This research presents the parallel control scheme of PID servo-driver for shaping of the curved glass. The designed system consists of a PC, main controller and 11 servo-drivers. Each elements are connected by using RS-232C and 8-bit bus communication. In order to guarantee the stability and the control performance, we use the LM629, a precision PID motion controller, and LMD18200, a H-bridge on the servo-drivers. PC calculates position values of 11 DC motors by using the pre-determined curvature value and offers the user interface environment operator.

• 대한수학회논문집
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• 제39권2호
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• pp.407-420
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• 2024

In this paper, we investigate some geometric properties of starlikeness connected with the hyperbolic cosine functions defined in the open unit disk. In particular, for the class of such starlike hyperbolic cosine functions, we determine the lower bounds of partial sums, Briot-Bouquet differential subordination associated with Bernardi integral operator, and bounds on some third Hankel determinants containing initial coefficients.

• 대한전자공학회논문지TE
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• 제39권3호
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• pp.65-70
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• 2002

본 논문에서는 이동하는 로봇을 제어하기 위한 웹 상에서의 시스템 구성을 논의한다. 즉, 웹에서의 제어 방법을 구체적으로 설명하고 실험한 결과를 나타내었다. 시스템은 서버 측에 있는 간단한 인터페이스를 엑세스하여 원격제어 한다. 이를 위해, 원격 사용자는 인터넷상에서 시스템을 원격으로 조절하기 위하여 www 브라우저가 설치된 범용 컴퓨터가 있어야 한다. 원격 사용자가 서버 측의 html파일을 구동하여 신호를 입력하면, 자바로 작성된 프로그램이 직렬포트에 연결된 기기를 구동한다. 원격제어 신호는 적외선 센서를 거쳐 라인트레이서에 전달되어 운행을 원격으로 제어한다. 웹에서의 시스템의 동작 확인을 위하여 시스템의 기기로는 라인트레이서를 사용하였다.