681079
Coronoid Systems with Perfect Matchings
Abstract A hexagonal system is a finite 2-connected plane graph in which every interior face is bounded by a regular hexagon. A coronoid system is obtained from a hexagonal system by deleting some interior vertices and/or interior edges such that a unique interior face which is bounded by a polygon with more than six edges emerges, and each edge on the outer perimeter belongs to a hexagon. In this paper, a necessary and sufficient condition is given for a coronoid system to have perfect matchings. Moreover, a criterion is established for those coronoid systems with perfect matchings that possess some edges which do not belong to any perfect matching.
30935891
K-coverable polyhex graphs
38715917
Perfect Matchings of Generalized Polyomino Graphs
3158206
Live updating operating systems using virtualization
Many critical IT infrastructures require non-disruptive operations. However, the operating systems thereon are far from perfect that patches and upgrades are frequently applied, in order to close vulnerabilities, add new features and enhance performance. To mitigate the loss of availability, such operating systems need to provide features such as live update through which patches and upgrades can be applied without having to stop and reboot the operating system. Unfortunately, most current live updating approaches cannot be easily applied to existing operating systems: some are tightly bound to specific design approaches (e.g. object-oriented); others can only be used under particular circumstances (e.g. quiescence states).In this paper, we propose using virtualization to provide the live update capability. The proposed approach allows a broad range of patches and upgrades to be applied at any time without the requirement of a quiescence state. Moreover, such approach shares good portability for its OS-transparency and is suitable for inclusion in general virtualization systems. We present a working prototype, LUCOS, which supports live update capability on Linux running on Xen virtual machine monitor. To demonstrate the applicability of our approach, we use real-life kernel patches from Linux kernel 2.6.10 to Linux kernel 2.6.11, and apply some of those kernel patches on the fly. Performance measurements show that our implementation incurs negligible performance overhead: a less than 1% performance degradation compared to a Xen-Linux. The time to apply a patch is also very minimal.
41515158
Error resilience for block loss with overlapped motion compensation
A new error resilience algorithm for recovering the lost blocks or motion vectors is presented. It combines the overlapped motion compensation and the side match criterion to make the effect of lost blocks subjectively imperceptible. The side match criterion takes advantage of the spatial contiguity and interpixel correlation of image to select the best-fit replacement among the motion vectors of spatially contiguous candidate blocks. Particularly, to mask the blocking artifacts, we incorporate an overlapping technique to create a subjectively closer approximation to the true error-free image.
32766485
Accelerating convergence in the Fermat-Weber location problem
This paper presents a simple procedure for accelerating convergence in a generalized Fermat-Weber problem with l"p distances. The main idea is to multiply the predetermined step size of the Weiszfeld algorithm by a factor which is a function of the parameter p. The form of this function is derived from the local convergence properties of the iterative sequence. Computational results are obtained which demonstrate that the total number of iterations to meet a given stopping criterion will be reduced substantially by the new step size, with the most dramatic results being observed for values of p close to 1.
30314810
Non-Associative Parallel Prefix Computation
Abstract Associativity of a binary operation allows many applications that are not possible with a non-associative binary operation. We propose a method to transform a binary expression into an associative one and present two related applications.
10137544
Diagnosing Java Programs with Static Abstractions of Data Structures
Model-based software debugging helps users to find program errors and thus to reduce the overall costs for software development. In this paper, we extend our previous work to diagnose common data structure errors. The proposed logical program model derives from a collection of indexed object relations, which capture the underlying data structures at the abstraction level of objects. A case study suggests that the counterexample with the diagnoses can help the user to understand the nature of program errors and thus speed up error correction.