Jing-ho Yan

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Meysam Alishahi

Shahrood University of Technology

Linfan Mao

Wolfgang Slany

Dr. V. K. Chaubey

North-Eastern Hill University, Hill Univ. Shillong-793022 (India)

Sukanto Bhattacharya

Deakin University

Florentin Smarandache

University of New Mexico

Maike Buchin

Andras Pluhar

Saleh Omran

South Valley University

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Papers by Jing-ho Yan

Equitable coloring of interval graphs and products of graphs

We confirm the equitable $\Delta$-coloring conjecture for interval graphs and establish the monot... more

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Quasi-threshold Graphs

by Jing-ho Yan and Gerard Chang

Discrete Applied Mathematics, 1996

Quasi-threshold graphs are defined recursively by the following rules: 1.(1) K1 is a quasi-thresh... more Quasi-threshold graphs are defined recursively by the following rules: 1.(1) K1 is a quasi-threshold graph,2.(2) adding a new vertex adjacent to all vertices of a quasi-threshold graph results in a quasi-threshold graph,3.(3) the disjoint union of two quasi-threshold graphs is a quasi-threshold graph. This paper gives some new equivalent definitions of a quasi-threshold graph. From them, linear time recognition algorithms

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On L(2, 1)-labelings of Cartesian products of paths and cycles

Discrete Mathematics, 2004

A k-L(2,1)-labeling of a graph G is a function f from the vertex set V(G) to {0,1,…,k} such that ... more A k-L(2,1)-labeling of a graph G is a function f from the vertex set V(G) to {0,1,…,k} such that |f(u)−f(v)|⩾1 if d(u,v)=2 and |f(u)−f(v)|⩾2 if d(u,v)=1. The L(2,1)-labeling problem is to find the L(2,1)-labeling number λ(G) of a graph G which is the minimum cardinality k such that G has a k-L(2,1)-labeling. In this paper, we study L(2,1)-labeling numbers of

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Seamless channel transition for slotted generalized fibonacci broadcasting

Multimedia Systems, 2007

In this paper, we present a scheme that possess seamless channel transition property and is suita... more In this paper, we present a scheme that possess seamless channel transition property and is suitable for heterogeneous receivers simultaneously. We first modify the BroadCatch (MBC) scheme [29] by allowing an arbitrary number of base channels defined in BroadCatch. We then propose a seamless channel transition enhancement on top of MBC so that service provider can be capable of adjusting the channel allocation policy to make the most benefit out of the available bandwidth. MBC is not only adaptive to receivers with heterogeneous bandwidth capacities but also with zero heterogeneous scalability when channel transition is performed. With zero heterogeneous scalability, new clients can benefit from newly added server channels without paying any extra cost.

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Signed degree sequences of signed graphs

Journal of Graph Theory, 1997

A signed bipartite graph is a bipartite graph in which each edge is assigned a positive or a nega... more

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Bandwidth sums of block graphs and cacti

Journal of Combinatorial Optimization, 2014

ABSTRACT A labeling of a graph G is an injective function f:V(G)→ℤ. The bandwidth sum of a graph ... more ABSTRACT A labeling of a graph G is an injective function f:V(G)→ℤ. The bandwidth sum of a graph G with respect to a labeling f is $B_{s}^{f}(G) = \sum_{uv \in E(G)} |f(u)-f(v)|$ and the bandwidth sum of G is $B_{s}(G) = \min\{B_{s}^{f}(G)\colon f\mbox{ is a labeling of }G\}$ . In this paper, we determine bandwidth sums for some block graphs and cacti.

The path-partition problem in block graphs

Information Processing Letters, 1994

We present a linear-time algorithm for the path-partition problem in block graphs.

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On Cycle Sequences

by Jing-ho Yan and Li-da Tong

Graphs and Combinatorics, 2001

ABSTRACT For each vertex upsilon in a graph G, the maximum length of a cycle which passes through... more ABSTRACT For each vertex upsilon in a graph G, the maximum length of a cycle which passes through D is called the cycle number of upsilon, denoted by c(upsilon). A sequence a(1),a(2),...,a(n) of nonnegative integers is called a cycle sequence of a graph G if the vertices of G can be labeled as upsilon (1),upsilon (2),...,upsilon (n) such that a(i) = c(upsilon (i)) for 1 less than or equal to i less than or equal to n. We give;some sufficient and necessary conditions for a sequence to be a cycle sequence. We can thereby derive a polynomial time procedure for recognizing cycle sequences.

The bandwidth sum of join and composition of graphs

Discrete Mathematics, 2005

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A note on the Gallai–Roy–Vitaver Theorem

by Jing-ho Yan and Li-da Tong

Discrete Mathematics, 2002

ABSTRACT The well-known theorem by Gallai-Roy-Vitaver says that every digraph G has a directed pa... more ABSTRACT The well-known theorem by Gallai-Roy-Vitaver says that every digraph G has a directed path with at least χ(G) vertices; hence this holds also for graphs. Li strengthened the digraph result by showing that the directed path can be constrained to start from any vertex that can reach all others. For a graph G given a proper χ(G)-coloring, he proved that the path can be required to start at any vertex and visit vertices of all colors. We give a shorter proof of this. He conjectured that the same holds for digraphs; we provide a strongly connected counterexample. We also give another extension of the Gallai-Roy-Vitaver Theorem on graphs.

Algorithmic aspects of the generalized clique-transversal problem on chordal graphs

Discrete Applied Mathematics, 1996

Suppose G=( V,E) is a graph in which each maximal clique Ci is associated with an integer ri, whe... more Suppose G=( V,E) is a graph in which each maximal clique Ci is associated with an integer ri, where 0 < ri < ICi 1. The generalized clique transversal problem is to determine the minimum cardinality of a subset D of V such that ID n Cij >ri for every maximal clique Ci of G. The problem includes the clique-transversal problem, the i, 1 clique-cover problem, and for perfect graphs, the maximum q-colorable subgraph problems as special cases. This paper gives complexity results for the problem on subclasses of chordal graphs, e.g., strongly chordal graphs, k-trees, split graphs, and undirected path graphs.

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The profile of the Cartesian product of graphs

Discrete Applied Mathematics, 2008

Given a graph G, a proper labeling f of G is a one-to-one function from

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k-Path Partitions in Trees

by Stephen Hedetniemi and Jing-ho Yan

Discrete Applied Mathematics, 1997

For a fixed positive integer k, the k-path partition problem is to partition the vertex set of a ... more For a fixed positive integer k, the k-path partition problem is to partition the vertex set of a graph into the smallest number of paths such that each path has at most k vertices. The 2-path partition problem is equivalent to the edge-cover problem. This paper presents a linear-time algorithm for the k-path partition problem in trees. The algorithm is

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Equitable coloring of interval graphs and products of graphs

We confirm the equitable $\Delta$-coloring conjecture for interval graphs and establish the monot... more

Download

Quasi-threshold Graphs

by Jing-ho Yan and Gerard Chang

Discrete Applied Mathematics, 1996

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On L(2, 1)-labelings of Cartesian products of paths and cycles

Discrete Mathematics, 2004