Journal of Algorithms and ComputationJournal of Algorithms and Computation
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Feed provided by Journal of Algorithms and Computation. Click to visit.Sharp Upper bounds for Multiplicative Version of Degree Distance and Multiplicative Version of ...
https://jac.ut.ac.ir/article_7989_117.html
In $1994,$ degree distance of a graph was introduced by Dobrynin, Kochetova and Gutman. And Gutman proposed the Gutman index of a graph in $1994.$ In this paper, we introduce the concepts of multiplicative version of degree distance and the multiplicative version of Gutman index of a graph. We find the sharp upper bound for the multiplicative version of degree distance and multiplicative version of Gutman index of cartesian product of two connected graphs. And we compute the exact value for the cartesian product of two complete graphs. Using this result, we prove that our bound is tight. Also, we obtain the sharp upper bound for the multiplicative version of degree distance and the multiplicative version of Gutman index of strong product of connected and complete graphs. And we observe the exact value for the strong product of two complete graphs. From this, we prove that our bound is tight.Thu, 31 May 2018 19:30:00 +0100Improved label propagation algorithms with node attribute and link strength for community detection
https://jac.ut.ac.ir/article_68238_117.html
Community detection has a wide variety of applications in different fields such as data mining, social network analysis and so on. Label Propagation Algorithm (LPA) is a simple and fast community detection algorithm, but it has low accuracy. There have been presented some advanced versions of LPA in recent years such as CenLP and WILPAS. In this paper, we present improved versions of CenLP and WILPAS methods called CenLP+ and WILPAS+ respectively. Experiments and benchmarks demonstrate that while CenLP+ is as fast as CenLP, it outperforms CenLP on both synthetic and real-world networks. Moreover, while accuracy of WILPAS+ on synthetic networks comparable with that of WILPAS, on real-world networks, WILPAS+ excels WILPAS. In addition, whereas both presented methods CenLP+ and WILPAS+ show high accuracy on synthetic networks, on real-world networks they outperform remarkably all other tested label propagation based algorithms for community detection. Therefore, since CenLP+ and WILPAS+ are both fast and accurate, specially on real-world networks, they can efficiently reveal community structures of mega-scale social networks.Thu, 31 May 2018 19:30:00 +0100Tree Technology for Memory Confidentiality Integrity Protection
https://jac.ut.ac.ir/article_68338_117.html
PCIPunderline{ }Tree is a Parallelized memory Confidentiality and Integrity Protection technology (PCIP) method that pre-diffuses and encrypts the data stored in off-chip counter value for confidentiality and integrity protection of data, adding redundant checking data to the protection data block to ensure the integrity and confidentiality of the memory data. Then use the Simple Scalar tool to run 10 processors (SPEC2000) benchmark programs to simulation test. The result shows that the PCIPunderline{ }Tree method is greatly improved the running efficiency and the efficiency of encryption methods to compare with the Parallelized Encryption and Integrity Checking Engine (PE-ICE) method, at the same time, through the redundant data to check data integrity is better than using complex Hash algorithm to calculate the checking value and reduce system delay, reduce storage overhead chip, and ensure the real-time encryption and checking.Thu, 31 May 2018 19:30:00 +0100Improper Filter Reduction
https://jac.ut.ac.ir/article_68340_117.html
Combinatorial filters, which are discrete representations of estimationprocesses, have been the subject of increasing interest from the roboticscommunity in recent years.%This paper considers automatic reduction of combinatorial filters to a givensize, even if that reduction necessitates changes to the filter's behavior.%We introduce an algorithmic problem called emph{improper filter reduction}, in which the input is a combinatorial filter $F$ alongwith an integer $k$ representing the target size. The output is anothercombinatorial filter $F'$ with at most $k$ states, such that the differencein behavior between $F$ and $F'$ is minimal.We present two methods for measuring the distance between pairs of filters, describe dynamic programming algorithms for computing these distances, andshow that improper filter reduction is NP-hard under these methods.%We then describe two heuristic algorithms for improper filter reduction, onechanged{greedy sequential} approach, and one randomized global approach based on prior workon weighted improper graph coloring. We have implemented these algorithmsand analyze the results of three sets of experiments.Thu, 31 May 2018 19:30:00 +0100One Modulo Three Geometric Mean Graphs
https://jac.ut.ac.ir/article_68342_117.html
A graph $G$ is said to be one modulo three geometric mean graph if there is an injective function $phi$ from the vertex set of $G$ to the set ${a mid 1leq a leq 3q-2} $ and either $aequiv 0(mod 3) $ or $ aequiv 1(mod 3)}$ where $q$ is the number of edges of $G$ and $phi$ induces a bijection $phi^{*}$ form the edge set of $G$ to ${a mid 1leq aleq 3q-2 $ and $ aequiv 1(mod3)}$ given by $phi^{*}(uv)=leftlceil sqrt{phi(u)phi(v)}rightrceil$ or $leftlfloor sqrt{phi(u)phi(v)}rightrfloor$ and the function $phi$ is called one modulo three geometric mean labeling of $G$. In this paper, we establish that some families of graphs admit one modulo three geometric mean labeling.Thu, 31 May 2018 19:30:00 +0100Vulnerability in Networks - A Survey
https://jac.ut.ac.ir/article_68367_117.html
The analysis of vulnerability in networks generally involves some questionsabout how the underlying graph is connected. One is naturally interestedin studying the types of disruption in the network that maybe causedby failures of certain links or nodes. In terms of a graph, the concept ofconnectedness is used in different forms to study many of the measuresof vulnerability. When certain vertices or edges of a connected graphare deleted, one wants to know whether the remaining graph is stillconnected, and if so, what its vertex - or edge - connectivity is. If on theother hand, the graph is disconnected, the determination of the number ofits components or their orders is useful. Our purpose here is to describeand analyses the current status of the vulnerability measures, identify itsmore interesting variants, and suggest a most suitable measure ofvulnerability.Thu, 31 May 2018 19:30:00 +0100Pointed Conflict-Free Colouring of Digraphs
https://jac.ut.ac.ir/article_68425_117.html
In a pointed conflict-free partial (PCFP) colouring of a digraph, each vertex has at least one in-neighbour with unique colour. In this paper, it is proved that PCFP $k$-colourability of digraphs is NP-complete, for any $k >0$. Nevertheless for paths and cycles, one can in linear time find a PCFP colouring with a minimum number of colours and for a given tree, one can find a PCFP 2-colouring. In this paper a bipartite digraph whose arcs start from the same part is called a one-way bipartite digraph. It is proved every one-way bipartite planar digraph has a PCFP 6-colouring, every one-way bipartite planar digraph whose each vertex has in-degree zero or greater than one, has a PCFP 5-colouring and every one-way bipartite planar digraph whose each vertex has in-degree zero or greater than two, has a PCFP 2-colouring. Two simple algorithms are proposed for finding a PCFP colouring of a given digraph such that the number of colours used is not more than the maximum out-degree of the vertices. For a digraph with a given PCFP colouring, it is shown how to recolour the vertices after vertex or arc insertion or deletion to obtain a PCFP colouring for the new digraph.Thu, 31 May 2018 19:30:00 +0100Defining the Tipping Point Based on Conditionally Convergent Series: Explaining the Indeterminacy
https://jac.ut.ac.ir/article_68630_117.html
Tipping Point refers to the moment when an adaption or infection sustains itself in network without further external inputs. Until now, studies have mainly focused on the occurrence of the Tipping Point and what it leads to rather than what precedes it. This paper explores the situation leading to the Tipping Point during a process of diffusion in networks. The core of the debate is to manifest that the process can be introduced as an example of conditionally convergent series and that determining the tipping points’ occurrence is conditional to the arrangement of the series based on Reimann Rearrangement Theorem. Accordingly, the occurrence of curve does not follow a general formulation. That is called indeterminacy since that the predictions about tipping points for any diffusion over the network may include a variety of right answers, although such indeterminacy neither means there is no tipping point nor many.Thu, 31 May 2018 19:30:00 +0100$k$-Total prime cordial labeling of graphs
https://jac.ut.ac.ir/article_68651_117.html
In this paper we introduce a new graph labeling method called $k$-Total prime cordial. Let $G$ be a $(p,q)$ graph. Let $f:V(G)to{1,2, ldots, k}$ be a map where $k in mathbb{N}$ and $k>1$. For each edge $uv$, assign the label $gcd(f(u),f(v))$. $f$ is called $k$-Total prime cordial labeling of $G$ if $left|t_{f}(i)-t_{f}(j)right|leq 1$, $i,j in {1,2, ldots, k}$ where $t_{f}(x)$ denotes the total number of vertices and the edges labeled with $x$. We investigate k-total prime cordial labeling of some graphs and study the 4-total prime cordial labeling of path, cycle, complete graph etc.Thu, 31 May 2018 19:30:00 +0100