16598523
Algorithmic Aspects of the Generalized Clique-transversal Problem on Chordal Graphs
Suppose G = (V, E) is a graph in which each maximal clique Ci is associated with an integer ri, where 0 ⩽ ri ⩽ ¦Ci¦. The generalized clique transversal problem is to determine the minimum cardinality of a subset D of V such that ¦D ∩ Ci¦ ⩾ 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.
36905463
Quasi-threshold Graphs
Abstract 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 follow. We also give linear time algorithms for the edge domination problem and the bandwidth problem in this class of graphs.
1812621
A Data Storage Mechanism for Peer-to-Peer Based Decentralised Workflow Systems
This paper proposes an innovative data storage mechanism for decentralised workflow systems. The research is based on a peer-to-peer workflow architecture in which various nodes communicate with each other directly to carry out workflow functions. In this approach, a process is partitioned into separate tasks, and then individual tasks are passed to appropriate nodes. To realise this approach, a data repository independent process notation is provided. Moreover, this paper also designs communication protocols to maintain data in a dynamic environment. The key distinction of this approach is to propose a “know what you should know” policy to reflect the nature of applications.
4917474
Effective Visualisation of Workflow Enactment
Although most existing teamwork management systems support user-friendly interface to some extent, few of them have take into consideration of the special requirements of workflow visualisation. This paper realises the unique features of visualisation for run-time workflow, i.e., workflow enactment and execution. We present a detailed discussion of the emerging problems against the general aesthetic criteria for drawing the workflow layout. In order to support most essential workflow enactment facilities, the following three mechanisms are provided. Firstly, Sugiyama algorithm has been systematically incorporated into our prototype to create well structured workflow layout initially. Secondly, when the workflow process dynamically changes, we can adjust workflow layout by our force-scan algorithm to retain the mental maps created earlier among team members. Thirdly, we have also applied the technique of the fisheye view to offer a context focus mechanism for workflow users and to utilise the screen size more effectively. With these visualisation techniques, a better atmosphere may be facilitated for teamwork.
6655534
Wing transmission for a micromechanical flying insect
Flapping wings provide unmatched manoeuvrability for flying microrobots. Recent advances in modelling insect aerodynamics show that adequate wing rotation at the end of the stroke is essential for generating adequate flight forces. We developed a thorax structure using four bar frames combined with an extensible fan-fold wing to provide adequate wing stroke and rotation. Flow measurements on a scale model of the beating wing show promising aerodynamics. Calculations using a simple resonant mechanical circuit model show that piezoelectric actuators can generate sufficient power, force and stroke to drive the wings at 150 Hz.
15557099
Enacting Business Processes in a Decentralised Environment with p2p-Based Workflow Support
Traditionally, workflow adopts a centralised client/server architecture to enact processes, which has exhibited many weaknesses. This paper combines concepts from workflow technology and peer-to-peer computing and presents an innovative approach to support decentralised process enactment. With this approach, both process instantiation and instance execution are carried out in a genuinely decentralised fashion, which reflects applications’ increasingly distributed nature better. In general, the process instance is created with relevant participants creating various task instances at different locations. In addition, instance execution is coordinated through direct communication among relevant workflow participants.
5296157
A Novel Scalable Algorithm for Supervised Subspace Learning
Subspace learning approaches aim to discover important statistical distribution on lower dimensions for high dimensional data. Methods such as principal component analysis (PCA) do not make use of the class information, and linear discriminant analysis (LDA) could not be performed efficiently in a scalable way. In this paper, we propose a novel highly scalable supervised subspace learning algorithm called as supervised Kampong measure (SKM). It assigns data points as close as possible to their corresponding class mean, simultaneously assigns data points to be as far as possible from the other class means in the transformed lower dimensional subspace. Theoretical derivation shows that our algorithm is not limited by the number of classes or the singularity problem faced by LDA. Furthermore, our algorithm can be executed in an incremental manner in which learning is done in an online fashion as data streams are received. Experimental results on several datasets, including a very large text data set RCV1, show the outstanding performance of our proposed algorithm on classification problems as compared to PCA, LDA and a popular feature selection approach, information gain (IG).