20 research outputs found
Upper bounds for the 2-hued chromatic number of graphs in terms of the independence number
A 2-hued coloring of a graph (also known as conditional -coloring
and dynamic coloring) is a coloring such that for every vertex of
degree at least , the neighbors of receive at least colors. The
smallest integer such that has a 2-hued coloring with colors, is
called the {\it 2-hued chromatic number} of and denoted by . In
this paper, we will show that if is a regular graph, then and if is a graph and
, then and in general case if is a graph, then .Comment: Dynamic chromatic number; conditional (k, 2)-coloring; 2-hued
chromatic number; 2-hued coloring; Independence number; Probabilistic metho
Sigma Partitioning: Complexity and Random Graphs
A of a graph is a partition of the vertices
into sets such that for every two adjacent vertices and
there is an index such that and have different numbers of
neighbors in . The of a graph , denoted by
, is the minimum number such that has a sigma partitioning
. Also, a of a graph is a
function , such that for every two adjacent
vertices and of , ( means that and are adjacent). The of , denoted by , is the minimum number such
that has a lucky labeling . It was
conjectured in [Inform. Process. Lett., 112(4):109--112, 2012] that it is -complete to decide whether for a given 3-regular
graph . In this work, we prove this conjecture. Among other results, we give
an upper bound of five for the sigma number of a uniformly random graph
Optimal Sensor Deception to Deviate from an Allowed Itinerary
In this work, we study a class of deception planning problems in which an
agent aims to alter a security monitoring system's sensor readings so as to
disguise its adversarial itinerary as an allowed itinerary in the environment.
The adversarial itinerary set and allowed itinerary set are captured by regular
languages. To deviate without being detected, we investigate whether there
exists a strategy for the agent to alter the sensor readings, with a minimal
cost, such that for any of those paths it takes, the system thinks the agent
took a path within the allowed itinerary. Our formulation assumes an offline
sensor alteration where the agent determines the sensor alteration strategy and
implement it, and then carry out any path in its deviation itinerary. We prove
that the problem of solving the optimal sensor alteration is NP-hard, by a
reduction from the directed multi-cut problem. Further, we present an exact
algorithm based on integer linear programming and demonstrate the correctness
and the efficacy of the algorithm in case studies
Modeling of Steam Distillation Mechanism during Steam Injection Process Using Artificial Intelligence
Steam distillation as one of the important mechanisms has a great role in oil recovery in thermal methods and so it is important to simulate this process experimentally and theoretically. In this work, the simulation of steam distillation is performed on sixteen sets of crude oil data found in the literature. Artificial intelligence (AI) tools such as artificial neural network (ANN) and also adaptive
neurofuzzy interference system (ANFIS) are used in this study as effective methods to simulate the distillate recoveries of these sets of data. Thirteen sets of data were used to train the models and three sets were used to test the models. The developed models are highly compatible with respect to input oil properties and can predict the distillate yield with minimum entry. For showing the performance of the proposed models, simulation of steam distillation is also done using modified Peng-Robinson equation of state. Comparison between the calculated distillates by ANFIS and neural network models and also equation of state-based method indicates that the errors of the ANFIS model for training data and test data sets are lower than those of other methods