• Spatial Information Research
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• 제15권4호
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• pp.385-395
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• 2007

컴퓨터의 사용과 인터넷이 발달로 인해 데이터의 사용과 공유가 매우 증가하고 있으며, 그에 따라 불법적인 데이터의 보급도 발생하고 있다. 본 연구에서는 이러한 불법적인 데이터의 복제 문제를 해결하기 위해 디지털 워터마킹 기법을 제안한다. 특히, GIS에서 많이 사용하고 있는 데이터인 벡터데이터에 워터마크를 삽입하고, 소유권을 주장할 수 있는 워터마킹 방법을 제안한다. 연구에서 제안한 방법은 벡터데이터의 좌표에 이진 연산을 이용하여 워터마크를 직접 삽입을 하고, 워터마크를 삽입하는 역과정을 통해 워터마크를 추출하는 것이다. 실험 결과를 통해 제안한 방법이 벡터데이터에 대한 다양한 공격에 대해 강인함을 알 수 있었다.

• 대한자기공명의과학회:학술대회논문집
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• 대한자기공명의과학회 2001년도 제6차 학술대회 초록집
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• pp.57-63
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• 2001

Tensor 하면 최근 3D로 white matter내의 섬유질을 멋있게 그려내는 diffusion tensor를 연상합니다. 하지만 여기서 다룰 tensor는 수학적 연산자(operator)입니다. NMR 혹은 MRI에서 스핀을 vector로 표시하고, 이 vector 스핀이 90도 rf pulse에 의해서 z축에서 x-y Plane으로 rotation되는 것을 vector diagram으로 나타냅니다. 그런데 이 vector notation으로는 스핀에 일어나는 여러 현상들을 수식적으로 모델 하는데 한계가 있습니다. 그래서 도입된 모델이 product operator와 tensor operator입니다 (1, 2, 3). 한 예로 우리가 다루는 proton NMR 신호가 single quantum인데 23Na 등에는 multiple quantum 신호가 생기게 되며 이는 vector로는 나타낼 수가 없으며 tensor로 분석이 가능합니다 (4, 5).

• 대한전기학회:학술대회논문집
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• 대한전기학회 1994년도 하계학술대회 논문집 A
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• pp.307-312
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• 1994

In this investigation the PFM(Pulse Frequency Modulation} will be used for optimizing PWM inverter pulse pattern. In traditional the pulse frequency of PWM is kept const. But modulated PWM's frequency in this study, the sinusoidal inverter's performance should be improved. The PWM pulsepatterns are definitely controlled so that the time-integral function of the voltage vectors in the space vector notation may show a circular locus. Further, performance index will be minimized because of minimizing distortion of output current. Finally, we will implement itusingsingle-chip microprocessor.

• Korean Journal of Mathematics
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• 제30권4호
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• pp.561-569
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• 2022

In this paper, we study the generalization of the Banach contraction principle in the vector space, involving four rational square terms in the inequality, by using the notation of bilinear functional. We also present an extension of Selberg's inequality to vector space.

• 한국통신학회논문지
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• 제15권7호
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• pp.628-637
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• 1990

본 연구에서는 고속의 병렬 알고리즘을 이용하여 실시간 디지털 신호를 처리할 수 있는 16x16 고속의 CMOS 승산기를 설계하였다. 설계된 병렬 승산기는 modified Booth's 알고리즘과 Ling's approach를 이용하여 4열의 가산기와 8개의 Booth 디코더로 구성하였으며, 2's complement의 데이터와 계수를 처리할 수 있도록 설계하였다. 또한 VLSI 구현에 적합하도록 modulrity하고 regularity하게 모든 회로를 설계하고 규칙적으로 내부 배열을하여 testavility가 용이하도록 설계하였다.

• 대한의용생체공학회:의공학회지
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• 제8권2호
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• pp.171-176
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• 1987

Wiener filtering method was applied to the dual energy imaging procedure in digital radiography(D.R.). A linear scanning photodiode arrays with 1024 elements(0.6mm H 1.3mm pixel size) were used to obtain chest images in 0.7 sec. For high energy image acquisition, X-ray tube was set at 140KVp, 100mA with a rare-earth phosphor screen. Low energy image was obtained with X-ray tube setting at 70KVp, 150mA. These measured dual energy images are represented in the vector matrix notation as a linear discrete model including the additive random noise. Then, the object images are restored in the minimum mean square error sense using Wiener filtering method in the transformed domain. These restored high and low energy images are used for computation of the basis image decomposition. Then the basis images are linearly combined to produce bone or tissue selective images. Using this process, we could improve the signal to noise ratio characteristics in the material selective images.

• 소음진동
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• 제9권5호
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• pp.922-927
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• 1999

The objective of this paper is to obtain the contribution of each source to the spectrum of pressure, when there are multiple incoherent sources in near-field acoustic holography. For this objective, we have to obtain signals very coherent to the input signals of the sources. To obtain the very coherent signals, many people have measured pressure signals in the vincinity of the sources. However, it is sometimes difficult to locate microphones near to the sources so that the signals are very coherent to the input signals. This paper proposed a method to obtain the very coherent signals by near-field acoustic holography. Therefore, the proposed method does not require the measurement of pressure near to each source. Simulation results for two incoherent monopole sources showed the possibility of the proposed method.

• 대한수학회논문집
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• 제33권1호
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• pp.179-196
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• 2018

In this paper we extend the two q-additions with powers in the umbrae, define a q-multinomial-coefficient, which implies a vector version of the q-binomial theorem, and an arbitrary complex power of a JHC power series is shown to be equivalent to a special case of the first q-Lauricella function. We then present several q-analogues of hypergeometric integral formulas from the two books by Exton and the paper by Choi and Rathie. We also find multiple q-analogues of hypergeometric integral formulas from the recent paper by Kim. Finally, we prove several multiple q-hypergeometric integral formulas emanating from a paper by Koschmieder, which are special cases of more general formulas by Exton.

• 한국소음진동공학회논문집
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• 제15권5호
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• pp.527-535
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• 2005

This paper explains a general coupling system in terms of the system parameters. impedance of a cavity or mobility of a structure. To easily access the mechanism of the structural-acoustic coupled system, a simple expression is derived. A general coupled equation is also derived of a general coupled problem constituted a flexible structure and an opening boundary in terms of vector and matrix notation, and is analyzed the coupling phenomena using the understanding acquired simple coupled system. The paper shows that the general coupled equation is expanded version of the simple coupled equation by some limiting checks. The paper also shows that the degree of coupling is proportioned to a stiffness of the acoustic system and a modal coupling coefficient, but is in inverse proportion to a mass of the structural system and the difference of the excitation frequency and resonant frequency of the acoustic or structural system.

• 로봇학회논문지
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• 제18권1호
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• pp.37-47
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• 2023

This paper introduced how to construct Denavit-Hartenberg (DH) parameters from the Unified Robot Description Format (URDF). URDF is convenient for describing a robot even though the robot is very complex. On the other hand, DH convention is not an easy notation for many novices who want to describe a robot. Therefore, most vendors provide URDF and users prefer to use URDF to describe a robot. However, some controllers or algorithms are based on DH parameters to perform kinematics, dynamics, control, etc. To connect URDF and DH parameters, we present a three-step approach to construct DH parameters from URDF. The first step is to define the joint axis for constructing DH parameters. The second step is constructing DH parameters to define joint character. The final step is constructing DH parameters to define the coordinate frame of the child link. This approach is based on intuitive vector calculation and guarantees the uniqueness of DH parameters. To verify our approach, we applied our approach to a simple one-link robot, a manipulator with 6 DOF, and a quadruped robot with 3 DOF per leg. We verified that our approach worked well based on forward kinematic results.