• Journal of applied mathematics & informatics
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• 제17권1_2_3호
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• pp.1-23
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• 2005

The shortest-paths problem is a fundamental problem in graph theory and finds diverse applications in various fields. This is why shortest path algorithms have been designed more thoroughly than any other algorithm in graph theory. A large number of optimization problems are mathematically equivalent to the problem of finding shortest paths in a graph. The shortest-path between a pair of vertices is defined as the path with shortest length between the pair of vertices. The shortest path from one vertex to another often gives the best way to route a message between the vertices. This paper presents an $O(n^2)$ time sequential algorithm and an $O(n^2/p+logn)$ time parallel algorithm on EREW PRAM model for solving all pairs shortest paths problem on circular-arc graphs, where p and n represent respectively the number of processors and the number of vertices of the circular-arc graph.

• 한국정밀공학회지
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• 제24권8호통권197호
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• pp.50-57
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• 2007

In this paper, two types of novel planar Translational Parallel Manipulators (TPMs) by using parallelogram mechanism are conceived. One is made up of two Pa-P (Parallelogram-Prismatic) legs connecting the base to the moving platform. The other consists of two P-Pa legs, which is the kinematic inversion of the former. Since connecting links in a parallelogram mechanism are subject to only tensile/compressive load and all the heavy actuators are mounted at the base, the proposed manipulators can be applied for planar positioning/assembly tasks requiring high stiffness and high speed. The position, velocity, and statics are analyzed, and the design methodology using prescribed workspace and velocity transmission capability is presented. Finally, two types of prototype manipulators have been developed.

• International Journal of Reliability and Applications
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• 제8권2호
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• pp.137-151
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• 2007

Posbist reliability of typical systems is preliminarily discussed in Cai (1991). In this paper, we focus on the posbist reliability analysis of some typical systems in depth. First, the lifetime of the system is dealt as a fuzzy variable defined on the possibility space (U, ${\phi}$, $P_{oss}$) and the universe of discourse is expanded from (0, $+{\infty}$) to ($-{\infty},\;+{\infty}$). Then, a concrete possibility distribution function of the fuzzy variable is given, i.e., a Gaussian fuzzy variable. Finally, posbist reliability of typical systems (series, parallel, series-parallel, parallel-series, cold redundant system) is deduced. The expansion makes the proofs of some theorems straightforward and allows us to easily obtain the posbist reliability of typical systems. To illustrate the method a numerical example is given.

• 전기학회논문지P
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• 제57권3호
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• pp.323-327
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• 2008

We investigated the quench characteristics of a flux-lock type superconducting fault current limiter (SFCL) depending on the methods of the serial and parallel connections between the superconducting elements. The flux-lock type SFCL consists of two coils. The primary coil is wound in parallel to the secondary coil through an iron core, and the secondary coil is connected to the superconducting elements in series and parallel. In this paper, the analyses of voltage, current, and resistance of the superconducting elements connected in serial and parallel were performed to increase the power capacity of the flux-lock type SFCL. A part of the superconducting elements was not quenched in $2{\times}2$ serial connection between the elements and then the power burden of the quenched elements was increased. However the elements with $2{\times}2$ parallel connection was all quenched. This means that the power burden of each superconducting element can be reduced under the same conditions. We found that $2{\times}2$ parallel connection was more profitable for the current limiting effects and the increase of the power capacity.

• 한국운동역학회지
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• 제27권4호
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• pp.257-262
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• 2017

Objective: This study aimed to investigate the differences in skiing time and vertical ground reaction force (vGRF) between the basic parallel turn and short turn. Method: Eleven alpine ski instructors (age: $28.73{\pm}4.29yrs$, height: $172.36{\pm}6.30cm$, body mass: $71.45{\pm}9.16kg$, career: $11.09{\pm}2.70yrs$) participated in this study. Each skier was asked to perform a basic parallel turn and short turn on a $16^{\circ}$ groomed slope. A foot pressure measurement system was used to measure the skiing time and vGRF under the three plantar regions (forefoot, midfoot, rearfoot). Results: Skiing time decreased significantly in all three phases during the short turn (p<.05). In the initiation phase, the vGRF showed a greater decrease on the midfoot and rearfoot during the short turn (p<.05). In the steering phase 1, the vGRF showed a greater increase on the forefoot and decreased on the midfoot during the short turn (p<.05). In the steering phase 2, the vGRF showed a greater increase on the forefoot and rearfoot during the short turn (p<.05). Conclusion: Our findings proved that the skiing time and vGRF changed during the short turn. Consequently, we suggest that recreational skiers should decrease the skiing time of the steering phase compared to that of the initiation phase and increase the vGRF on the forefoot and rearfoot in the steering phase.

• 대한전자공학회논문지SD
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• 제48권2호
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• pp.28-34
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• 2011

본 논문에서는 H.264/AVC 인코더를 위한 하드웨어 지향 알고리즘의 정화소 및 부화소 움직임 예측 코어를 제안한다. 정화소 움직임 엔진의 경우 참조블록은 병렬 처리 내의 연속된 현재 블록들에 공유되어 데이터 재사용율을 높이고 오프칩 대역폭을 줄인다. 부화소 움직임 엔진의 경우 두 단계의 순차적 보간 신호 생성 대신 불필요한 후보 위치들 대신 1/2과 1/4 화소정밀도 신호를 병렬 기법으로 생성하여 처리량을 두배로 높인다. 또한 제안하는 H.264 움직임 예측 코어는 Chartered $0.18{\mu}m$ CMOS 1P5M 공정의 MPW(Multi-Project Wafer)를 통해 칩으로 제작되었으며 높은 처리량으로 HDTV 720p 30fps를 실시간 지원한다.

• 전자공학회논문지SC
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• 제39권4호
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• pp.36-42
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• 2002

본 논문에서는 유한체 GF($P^m$)상에서 모든 항의 계수가 이 아닌 두 다항식의 승산 알고리즘을 제시하였다. 제시된 승산 알고리즘을 이용하여 모듈 구조의 병렬 입-출력 승산기를 구성하였다. 제시된 승산기는 $(m+1)^2$개의 동일한 셀로 구성되었으며, 각각의 셀은 1개의 mod(p) 가산 게이트와 1개의 mod(p) 승산 게이트로 구성되었다. 본 논문에서 제시된 승산기는 클럭이 필요하지 않고 m개의 mod(p) 가산 게이트 지연시간과 1개의 mod(p) 승산 게이트 소자 지연시간만을 필요로 한다. 또한, 제시된 승산기는 규칙성과 셀 배열에 의한 모듈성을 가지므로 VLSI 회로 실현에 적합할 것이다.

• 호남수학학술지
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• 제31권3호
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• pp.421-428
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• 2009

Given operators X and Y acting on a Hilbert space $\mathcal{H}$, an interpolating operator is a bounded operator A such that AX = Y. In this paper, we showed the following : Let $\mathcal{L}$ be a subspace lattice acting on a Hilbert space $\mathcal{H}$ and let $X_i$ and $Y_i$ be operators in B($\mathcal{H}$) for i = 1, 2, ${\cdots}$. Let $P_i$ be the projection onto $\overline{rangeX_i}$ for all i = 1, 2, ${\cdots}$. If $P_kE$ = $EP_k$ for some k in $\mathbb{N}$ and all E in $\mathcal{L}$, then the following are equivalent: (1) $sup\;\{{\frac{{\parallel}E^{\perp}({\sum}^n_{i=1}Y_if_i){\parallel}}{{\parallel}E^{\perp}({\sum}^n_{i=1}Y_if_i){\parallel}}:f{\in}H,n{\in}{\mathbb{N}},E{\in}\mathcal{L}}\}$ < ${\infty}$ range $\overline{rangeY_k}\;=\;\overline{rangeX_k}\;=\;\mathcal{H}$, and < $X_kf,\;X_kg$ >=< $Y_kf,\;Y_kg$ > for some k in $\mathbb{N}$ and for all f and g in $\mathcal{H}$. (2) There exists an operator A in Alg$\mathcal{L}$ such that $AX_i$ = $Y_i$ for i = 1, 2, ${\cdots}$ and AA$^*$ = I = A$^*$A.

• Journal of applied mathematics & informatics
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• 제33권3_4호
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• pp.417-424
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• 2015

In this paper the following is proved: Let L be a subspace lattice on a Hilbert space H and X and Y be operators acting on a Hilbert space H. If XE = EX for each E ${\in}$ L, then there exists an operator A in AlgL such that AX = Y if and only if sup $\left{\frac{\parallel{XEf}\parallel}{\parallel{YEf}\parallel}\;:\;f{\in}H,\;E{\in}L\right}$ = K < $\infty$ and YE=EYE. Let x and y be non-zero vectors in H. Let P_x be the orthogonal pro-jection on sp(x). If EP_x = P_xE for each E $\in$ L, then the following are equivalent. (1) There exists an operator A in AlgL such that Ax = y. (2) < f, Ey > y =< f, Ey > Ey for each E ${\in}$ L and f ${\in}$ H.

• 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 >.