35009889
Tree Domination in Graphs
34040250
Connected domination critical graphs
Abstract A dominating set in a graph G is a connected dominating set of G if it induces a connected subgraph of G . The minimum number of vertices in a connected dominating set of G is called the connected domination number of G , and is denoted by γ c ( G ). The purpose of this paper is to initiate an investigation of those graphs which are critical in the following sense: for each υ, μ ϵ V (G) with υ not adjacent to u , γ c ( G + υ u ) c ( G ). Thus, G is k -γ c -critical if γ c ( G ) = k and for each edge e ∉ E ( G ), γ c ( G + e ) k . First we discuss whether some particular classes of graphs are γ c -critical. Then 2-γ c -critical graphs are characterized. Finally, the properties of the 3-γ c -critical graphs are studied.
28317923
Characterization of graphs with equal domination and connected domination numbers
Arumugam and Paulraj Joseph (Discrete Math 206 (1999) 45) have characterized trees, unicyclic graphs and cubic graphs with equal domination and connected domination numbers. In this paper, we extend their results and characterize the class of block graphs and cactus graphs for which the domination number is equal to the connected domination number.
428956
On a generalization of signed total dominating functions of graphs
36018188
A note on graphs with largest total k-domination number
21127516
On independent domination number of regular graphs
Abstract Let G be a simple graph. The independent domination number i ( G ) is the minimum cardinality among all maximal independent sets of G . Haviland (1995) conjectured that any connected regular graph G of order n and degree δ ⩽ n /2 satisfies i ( G ) ⩽ ⌈2 n /3 δ ⌉ δ /2. In this paper, we will settle the conjecture of Haviland in the negative by constructing counterexamples. Therefore a larger upper bound is expected. We will also show that a connected cubic graph G of order n ⩾ 8 satisfies i ( G ) ⩽ 2 n /5, providing a new upper bound for cubic graphs.
62228274
Norm-Based Agency for Designing Collaborative Information Systems
Information systems are organizations in which signs are created, processed and consumed. In order to fulfil the organizational goals and objec- tives, its members must understand their responsibilities and authorities, and must act co-operatively. The key to this organization and co-ordination lies in norms, which define responsibilities and authorities for each human agent, and estab- lish regularities of behaviour. In the context of co-operative work, where 'intelli- gent' software agents are involved, to understand the norms of behaviour of various human agents becomes critical. Software agents can perform some tasks autonomously on the user's behalf. Such delegation involves a set of complicated philosophical and legal issues. After discussion on delineation of various bound- aries of responsibility and authorities, this paper addresses norms and normative behaviour of human agents within an organization. It discusses the taxonomies of norms and a method of norm specification, with examples. Finally it presents an approach of norm-based agency for designing collaborative information systems and a case study of an insurance claim for illustration.
6235535
Articulation of Learners Requirements for Personalised Instructional Design in e-Learning Services
As e-Learning environments evolve, learners have become increasingly demanding on personalised learning which allows them to build their own knowledge pathway. This significant change in learning requirements imposes a new learning paradigm which ensures one-to-one learning with flexible mode of content configuration, and adaptive delivery and assessment. Although in the past years, Learning Management Systems (LMS) providers have upgraded system functionality to support instructional design for e-learning package, incorporating individual learners’ personal learning requirements in content design still remains challenging. To involve learners in the content design requires identification of their personal learning requirements. This paper presents a method for articulating individual learners’ learning requirements (e.g., learning styles, and prior knowledge), and representing them in a set of computable parameters in Learner’s Profile. These parameters will then be mapped onto instructional design strategies which determine a selection of suitable learning content and sequencing of content with adequate instruction in a learning package.
34683247
Two classes of perfect graphs
Abstract We present two classes of perfect graphs. The first class is defined through a construction used by Gallai in his investigation of comparability graphs; the second class contains those Berge graphs defined through a forbidden graph on five vertices.
32541131
A method for interactive articulation of information requirements for strategic decision support
Abstract Decision support for strategic management, an extension to the traditional decision support systems, has been seen as an important area of research where the theory, methods and technologies can bring in a great deal of benefit to the whole enterprise at the executive level. The work in the paper first of all examines two paradigms of information provision for strategic decision support. The information requirements for decision-making are studied to reveal that the level of detail, granularity, format of presentation, and broad range of information type are unique for the applications at the strategic level. The provision of relevant information involves articulation of requirements based on the decision problems described by the executive manager. Secondly, this paper presents the MITAIS approach that allows the user to describe a decision problem interactively and assists articulation of the problem into a presentation in a decision space, by prompting possible patterns of decision dimensions. It further assists a configuration of information requirements into an information space, which covers the information required for the identified problem. MITAIS comprises a set of techniques to support articulation of a decision problem into a decision space, configuration of information space and the mapping between these two spaces. A case study has been used throughout the paper to illustrate the method. A critical evaluation of the development of MITAIS has been carried out to assess the validity of the research. Finally, the paper is concluded with suggestions for future work.
15670300
Recognizing dart-free perfect graphs
A graph G is called a Berge graph if neither G nor its complement contains a chordless cycle whose length is odd and at least five; what we call a dart is the graph with vertices u,v,w,x,y and edges uv,vw,uy,vy,wy,xy; a graph is called dart-free if it has no induced subgraph isomorphic to the dart. We present a polynomial-time algorithm to recognize dart-free Berge graphs; this algorithm uses as a subroutine the polynomial-time algorithm for recognizing claw-free Berge graphs designed previously by Chvatal and Sbihi [J. Combin. Theory Ser. B, 44 (1988), pp. 154--176].