• Journal of information and communication convergence engineering
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• 제8권1호
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• pp.59-63
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• 2010

The shortest path between two points inside a simple polygon P is a minimum-length path among all paths connecting them which don't pass by the exterior of P. A linear time algorithm for computing the shortest path in a general simple polygon requires triangulating a given polygon as preprocessing. The linear time triangulating is known to very complex to understand and implement it. It is also inefficient in case that the input without very large size is given because its time complexity has a big constant factor. Two points of a polygon P are said to be L-visible from each other if they can be joined by a simple chain of at most two rectilinear line segments contained in P completely. An L-visible polygon P is a polygon such that there is a point from which every point of P is L-visible. We present the customized optimal shortest path algorithm for an L-visible polygon. Our algorithm doesn't require triangulating as preprocessing and consists of simple procedures such as construction of convex hulls and operations for convex polygons, so it is easy to implement and runs very fast in linear time.

• 대한수학회논문집
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• 제35권1호
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• pp.1-12
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• 2020

A pathos block line cut-vertex graph of a tree T, written P BL_c(T), is a graph whose vertices are the blocks, cut-vertices, and paths of a pathos of T, with two vertices of P BL_c(T) adjacent whenever the corresponding blocks of T have a vertex in common or the edge lies on the corresponding path of the pathos or one corresponds to a block B_i of T and the other corresponds to a cut-vertex c_j of T such that c_j is in B_i; two distinct pathos vertices P_m and P_n of P BL_c(T) are adjacent whenever the corresponding paths of the pathos P_m(v_i, v_j) and P_n(v_k, v_l) have a common vertex. We study the properties of P BL_c(T) and present the characterization of graphs whose P BL_c(T) are planar; outerplanar; maximal outerplanar; minimally nonouterplanar; eulerian; and hamiltonian. We further show that for any tree T, the crossing number of P BL_c(T) can never be one.

• Kyungpook Mathematical Journal
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• 제46권3호
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• pp.445-448
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• 2006

Let N be a normal subgroup of a path-connected topological group (G, $t$). In this paper, the authors consider the existence of path-connectedness in refined topologies in order to address the property of maximal path-connectedness in topological groups. In particular, refinements on $t$ and refinements on the quotient topology on G/N are studied. The preservation of path-connectedness in extending topologies and translation topologies is also considered.

• 한국환경과학회지
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• 제27권11호
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• pp.1073-1081
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• 2018

In this study, an operational data set was analysed by establishing a path model to figure out the actual cause-effect relationship of a wastewater treatment plant (WWTP); in particular, for the effluent concentrations of T-N and T-P. To develop the path models, data sets of operational records including effluent concentrations and operational factors were obtained from a field scale WWTP of $680,000m^3$ of treatment capacity. The models showed that the relationship networks with the correlation coefficients between variables for objective expressions indicated the strength of each relationship. The suggested path models were verified according to whether the analyzation results matched known theories well, but sophisticated minute theoric relationships could not be cropped out distinctly. This indicates that only a few paths with strong theoric casual relationships were represented as measured data due to the high non-linearity of the mechanism of the removal process in a biological wastewater treatment.

• 전기학회논문지P
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• 제60권3호
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• pp.126-132
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• 2011

A conventional LDO(Low Dropout Regulator) uses one OPAMP and one signal path. This means that OPAMP's DC Gain and Bandwidth can't optimize simultaneously within usable power. This also appears that regulation property and settling time of LDO can't improve at the same time. Based on this idea, a proposed LDO uses two OPAMP and has two signal path. To improve regulation property, OPAMP where is used in the path which qualities DC gain on a large scale, bandwidth designed narrowly. To improve settling time, OPAMP where is used in the path which qualities DC gain small, bandwidth designed widely. A designed LDO used 0.5um 1P2M process and provided 200mA of output current. A line regulation and load regulation is 12.6mV/V, 0.25mV/mA, respectively. And measured settling time is 1.5us in 5V supply voltage.

• 대한수학회논문집
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• 제27권4호
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• pp.665-668
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• 2012

For a given graph G we consider a set S(G) of all symmetric matrices A = [$a_{ij}$] whose nonzero entries are placed according to the location of the edges of the graph, i.e., for $i{\neq}j$, $a_{ij}{\neq}0$ if and only if vertex $i$ is adjacent to vertex $j$. The minimum rank mr(G) of the graph G is defined to be the smallest rank of a matrix in S(G). In general the computation of mr(G) is complicated, and so is that of the maximum multiplicity MaxMult(G) of an eigenvalue of a matrix in S(G) which is equal to $n$ - mr(G) where n is the number of vertices in G. However, for trees T, there is a recursive formula to compute MaxMult(T). In this note we show that this recursive formula for MaxMult(T) also computes the path cover number $p$(T) of the tree T. This gives an alternative proof of the interesting result, MaxMult(T) = $p$(T).

• 대한자원환경지질학회:학술대회논문집
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• 대한자원환경지질학회 2007년도 춘계 지질과학기술 공동학술대회
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• pp.143-145
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• 2007

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• 대한수학회보
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• 제46권3호
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• pp.521-534
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• 2009

In this paper we present new large-update primal-dual interior point algorithms for $P_*$ linear complementarity problems(LAPS) based on a class of kernel functions, ${\psi}(t)={\frac{t^{p+1}-1}{p+1}}+{\frac{1}{\sigma}}(e^{{\sigma}(1-t)}-1)$, p $\in$ [0, 1], ${\sigma}{\geq}1$. It is the first to use this class of kernel functions in the complexity analysis of interior point method(IPM) for $P_*$ LAPS. We showed that if a strictly feasible starting point is available, then new large-update primal-dual interior point algorithms for $P_*$ LAPS have $O((1+2+\kappa)n^{{\frac{1}{p+1}}}lognlog{\frac{n}{\varepsilon}})$ complexity bound. When p = 1, we have $O((1+2\kappa)\sqrt{n}lognlog\frac{n}{\varepsilon})$ complexity which is so far the best known complexity for large-update methods.

• 한국정보통신학회논문지
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• 제14권2호
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• pp.369-374
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• 2010

다각형 내부에 위치한 두 점 사이의 최단 경로는 다각형의 외부를 지나지 않는 경로 중에서 길이가 가장 짧은 경로를 말한다. 일반적인 단순 다각형에서 최단 경로를 구하는 선형 시간 알고리즘은 매우 복잡한 과정으로 알려진 삼각분할을 전처리과정으로 수행해야 한다. 따라서 이론적으로는 최적인 시간복잡도를 갖지만, 실제적으로는 구현이 어려울 뿐만 아니라 입력의 크기가 매우 크지 않은 한 수행 시간이 효율적이지 못하다. 본 논문에서는 다각형 내부의 모든 점들을 볼 수 있는 선분이 존재하는 다각형 부류인 선분가시 다각형의 내부에 위치한 두 점 사이의 최단 경로를 구하는 선형 시간 알고리즘을 제시한다. 이 알고리즘은 삼각 분할을 필요로 하지 않으며, 볼록 외피 구축 등 단순한 절차만으로 구성되어 있어 구현이 용이할 뿐만 아니라 수행 속도도 빠르다

• 한국농공학회지
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• 제38권2호
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• pp.133-144
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• 1996

To get accurate results, the realistic stress-strain relationships of soils are dependent on a number of factors such as soil types, density, stress levels and stress path. Such attempts are continuously being made by the developement of analytical models for soils incorporating all such factors. Isotropic compression-expansion test and a series of drained conventional triaxial tests with several stress path for Baekma river sand were performed to investigate parameters characteristics of Lade's single work hardening model dependant on the stress path. Using the computer program based on the regression analysis, the values of parameters for the model were determined. In conclusion, the parameters of Lade's model are little influenced by the stress paths. Though yield criterion parameters ( h, ${\alpha}$a) are much influenced by stress level and stress path, the parameters don't have influence on stress-strain behavior.