فهرست مطالب
Journal of Algorithms and Computation
Volume:47 Issue: 1, Jun 2016
- تاریخ انتشار: 1395/03/12
- تعداد عناوین: 12
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Pages 1-10
Let G be a (p, q) graph. Let k be an integer with 2 ≤ k ≤ p and f from V (G) to the set {1, 2, . . . , k} be a map. For each edge uv, assign the label |f(u) − f(v)|. The function f is called a k-difference cordial labeling of G if |νf (i) − vf (j)| ≤ 1 and |ef (0) − ef (1)| ≤ 1 where vf (x) denotes the number of vertices labelled with x (x ∈ {1, 2 . . . , k}), ef (1) and ef (0) respectively denote the number of edges labelled with 1 and not labelled with 1. A graph with a k-difference cordial labeling is called a k-difference cordial graph. In this paper we investigate the 3-difference cordial labeling of wheel, helms, flower graph, sunflower graph, lotus inside a circle, closed helm, and double wheel.the formula is not displayed correctly!
Keywords: Path, cycle, Wheel, Star -
Pages 11-19
Many graph theoretical parameters have been used to describe the vulnerability of communication networks, including toughness, binding number, rate of disruption, neighbor-connectivity, integrity, mean integrity, edgeconnectivity vector, l-connectivity and tenacity. In this paper we discuss Integrity and its properties in vulnerability calculation. The integrity of a graph G, I(G), is defined to be min(| S | +m(G − S)) where S ⊂ V (G) and m(G − S) is the maximum order of the components of G − S. Similarly the edge-integrity of G is I′(G) := min(| S | +m(G − S)) where now S ⊆ E(G). Here and through the remaining sections, by an I-set (with respect to some prescribed graph G) we will mean a set S ⊂ V (G) for which I(G) =| S | +m(G − S). We define an I′-set similarly. In this paper we show a lower bound on the edgeintegrity of graphs and present an algorithm for its computation.the formula is not displayed correctly!
Keywords: Integrity parameter, toughness, neighborconnectivity, mean integrity, edge-connectivity vector, l-connectivity, tenacity -
Pages 21-26Avila and Molina [1] introduced the notion of generalized weak structures which naturally generalize minimal structures, generalized topologies and weak structures and the structures α(g),π(g),σ(g) and β (g). This work is a further investigation of generalized weak structures due to Avila and Molina. Further we introduce the structures ro(g) and rc(g) and study the properties of the structures ro(g), rc(g), and also further properties of α(g),π(g),σ(g) and β (g) due to [1].Keywords: Generalized weak structure, ro(g), rc(g), α (g), π(g), σ(g), β (g)
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Pages 27-36We consider online scheduling of jobs with speci c release time on m identical machines. Each job has a weight and a size; the goal is maximizing total weight of completed jobs. At release time of a job it must immediately be scheduled on a machine or it will be rejected. It is also allowed during execution of a job to preempt it; however, it will be lost and only weight of completed jobs contribute on pro t of the algorithm. In this paper we study D-benevolent instances which is a wide and standard class and we give a new algorithm, that admits (2m + 4)-competitive ratio. It is almost half of the previous known upper bound for this problem.Keywords: Online Algorithms Scheduling Identical Machine, Upper bound
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Pages 37-52
An H-magic labeling in a H-decomposable graph G is a bijection f : V (G) ∪ E(G) → {1, 2, ..., p + q} such that for every copy H in the decomposition, ΣνεV(H) f(v) + ΣeεE(H) f(e) is constant. f is said to be H-E-super magic if f(E(G)) = {1, 2, · · · , q}. A family of subgraphs H1,H2, · · · ,Hh of G is a mixed cycle-decomposition of G if every subgraph Hi is isomorphic to some cycle Ck, for k ≥ 3, E(Hi) ∩ E(Hj) = ∅ for i ≠ j and ∪hi=1E(Hi) = E(G). In this paper, we prove that K2m,2n is mixed cycle-E-super magic decomposable where m ≥ 2, n ≥ 3, with the help of the results found in [1].the formula is not displayed correctly!
Keywords: H-decomposable graph, H-E-super magic labeling, mixed cycle-E-super magic decomposable graph -
Pages 53-62In this paper, we study the Generalized Bin Covering problem. For this problem an exact algorithm is introduced which can nd optimal solution for small scale instances. To nd a solution near optimal for large scale instances, a heuristic algorithm has been proposed. By computational experiments, the eciency of the heuristic algorithm is assessed.Keywords: Generalized Bin Covering Problem, heuristic algorithm, greedy algorithm
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Pages 63-78The Zarankiewicz number z(b; s) is the maximum size of a subgraph of Kb,b which does not contain Ks,s as a subgraph. The two-color bipartite Ramsey number b(s, t) is the smallest integer b such that any coloring of the edges of Kb,b with two colors contains a Ks,s in the rst color or a Kt,t in the second color.In this work, we design and exploit a computational method for bounding and computing Zarankiewicz numbers. Using it, we obtain several new values and bounds on z(b; s) for 3≤s≤6. Our approach and new knowledge about z(b; s) permit us to improve some of the results on bipartite Ramsey numbers obtained byKeywords: Zarankiewicz number, bipartite Ramsey number
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Pages 79-92In this paper we restrict every set splitting problem to the special case in which every set has just three elements. This restricted version is also NP-complete. Then, we introduce a general conversion from any set splitting problem to 3-set splitting. Then we introduce a randomize algorithm, and we use Markov chain model for run time complexity analysis of this algorithm. In the last section of this paper we introduce "Fast Split" algorithm.Keywords: NP-complete problem, set splitting problem, SAT problem, Markov chain
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Pages 93-99In this paper we proposed a Cellular Automaton based local algorithm to solve the autonomously sensor gathering problem in Mobile Wireless Sensor Networks (MWSN). In this problem initially the connected mobile sensors deployed in the network and goal is gather all sensors into one location. The sensors decide to move only based on their local information. Cellular Automaton (CA) as dynamical systems in which space and time are discrete and rules are local, is proper candidate to simulate and analyze the problem. Using CA presents a better understanding of the problem.Keywords: Mobile Wireless Sensor Network, Mobile Sensor Gathering, Cellular Automata, Local Algorithm
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Pages 101-117In this paper, a mathematical method is proposed to formulate a generalized ordering problem. This model is formed as a linear optimization model in which some variables are binary. The constraints of the problem have been analyzed with the emphasis on the assessment of their importance in the formulation. On the one hand, these constraints enforce conditions on an arbitrary subgraph and then give sufficient conditions for feasibility, on the other hand, they provide a natural way to generalize the applied aspects of the model without increasing the number of the binary variables.Keywords: linear programming, integer programming, minimum ordering
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Pages 119-125
The edge tenacity Te(G) of a graph G is de ned as:Te(G) = min {[|X|+τ(G-X)]/[ω(G-X)-1]|X ⊆ E(G) and ω(G-X) > 1} where the minimum is taken over every edge-cutset X that separates G into ω(G - X) components, and by τ(G - X) we denote the order of a largest component of G. The objective of this paper is to determine this quantity for split graphs. Let G = (Z; I; E) be a noncomplete connected split graph with minimum vertex degree δ(G) we prove that if δ(G)≥|E(G)|/[|V(G)|-1] then its edge-tenacity is |E(G)|/[|V(G)|-1] .the formula is not displayed correctly!
Keywords: Vertex degree, split graphs, edge tenacity -
Pages 127-135
The tenacity of a graph G, T(G), is de ned by T(G) = min{[|S|+τ(G-S)]/[ω(G-S)]}, where the minimum is taken over all vertex cutsets S of G. We de ne τ(G - S) to be the number of the vertices in the largest component of the graph G - S, and ω(G - S) be the number of components of G - S.In this paper a lower bound for the tenacity T(G) of a graph with genus γ(G) is obtained using the graph's connectivity κ(G). Then we show that such a bound for almost all toroidal graphs is best possible.the formula is not displayed correctly!
Keywords: genus, graph's connectivity, toroidal graphs