2037433
An upper bound for ramsey numbers
Let G″ be a graph obtained from G by deleting two vertices. It is shown that r(G, H) ⩽ A + B + 2 + 2 (A2 + AB + B2)3 where A = r(G″, H) and B = r(G,H″).
8083367
On Some Three-Color Ramsey Numbers
Abstract. In this paper we study three-color Ramsey numbers. Let Ki,j denote a complete i by j bipartite graph. We shall show that (i) for any connected graphs G1, G2 and G3, if r(G1, G2)≥s(G3), then r(G1, G2, G3)≥(r(G1, G2)−1)(χ(G3)−1)+s(G3), where s(G3) is the chromatic surplus of G3; (ii) (k+m−2)(n−1)+1≤r(K1,k, K1,m, Kn)≤ (k+m−1)(n−1)+1, and if k or m is odd, the second inequality becomes an equality; (iii) for any fixed m≥k≥2, there is a constant c such that r(Kk,m, Kk,m, Kn)≤c(n/logn), and r(C2m, C2m, Kn)≤c(n/logn)m/(m−1) for sufficiently large n.
206570728
On Book-Complete Graph Ramsey Numbers
It is shown that a graph of orderNand average degreedthat does not contain the bookBm=K1+K1, mas a subgraph has independence number at leastNf(d), wheref(x)~(logx/x)(x?∞). From this result we find that the book-complete graph Ramsey number satisfiesr(Bm, Kn)?mn2/log(n/e). It is also shown that for every treeTmwithmedges,r(K1+Tm,Kn)?(2m?1)n2/log(n/e).
34644814
The Independence Number of Graphs with a Forbidden Cycle and Ramsey Numbers
Let k ≥ 5 be a fixed integer and let m = ⌊(k − 1)/2⌋. It is shown that the independence number of a Ck-free graph is at least c1[∑ d(v)1/(m − 1)](m − 1)/m and that, for odd k, the Ramsey number r(Ck, Kn) is at most c2(nm + 1/log n)1/m, where c1 = c1(m) > 0 and c2 = c2(m) > 0.
1087466
Independence numbers of hypergraphs with sparse neighborhoods
Let H be a hypergraph with N vertices and average degree d. Suppose that the neighborhoods of H are sparse, then its independence number is at least cN(log d/d), where c > 0 is a constant. In particular, let integers r ≥ 3 and n ≥ 1 be fixed, and let H be r-uniform, triangle-free and linear, then its independence number is at least cN logn d/d for all sufficiently large d.
7038620
Practical inference control for data cubes
The fundamental problem for inference control in data cubes is how to efficiently calculate the lower and upper bounds for each cell value given the aggregations of cell values over multiple dimensions. In this paper, we provide the first practical solution for estimating exact bounds in two-dimensional irregular data cubes (i.e., data cubes in which certain cell values are known to a snooper). Our results imply that the exact bounds cannot be obtained by a direct application of the Frechet bounds in some cases. We then propose a new approach to improve the classic Frechet bounds for any high-dimensional data cube in the most general case. The proposed approach improves upon the Frechet bounds in the sense that it gives bounds that are at least as tight as those computed by Frechet, yet is simpler in terms of time complexity. Based on our solutions to the fundamental problem, we discuss two security applications, privacy protection of released data and fine-grained access control and auditing
17005291
Institution Morphisms for Relating OWL and Z
Checking for properties of Web ontologies is important for the development of reliable Semantic Web systems. Software specification and verification tools can be used to complement the Knowledge Representation tools in reasoning about Semantic Web. The key to this approach is to develop sound transformation techniques from Web ontology to software specifications so that the associated verification tools can be applied to check the transformed specification models. Our previous work has demonstrated a practical approach to translating Web ontologies to Z specifications. However, from a sound engineering point of view, the translation is lacking the theoretical work that can formally relate the respective underlying logical systems of OWL and Z. In this paper, we take the advantage that the logics underlying OWL and Z can be represented as institutions and we show that the institution comorphism provides a formal semantic foundation for the transformation from OWL to Z.
20878415
An approximation algorithm for the edge-dilation k-center problem,
We provide an approximation algorithm for selecting centers in a complete graph so as to minimize the maximum ratio of the distance between any two nodes via their respective centers to their true graph distance. Placing centers under such an objective function is important in designing efficient communication networks which rely on hubs for routing.
10776344
Robust Head Tracking Based on a Multi-State Particle Filter
This paper proposes a novel method for robust and automatic realtime head tracking by fusing face and head cues within a multi-state particle filter. Due to large appearance variability of human head, most existing head tracking methods use little object-specific prior knowledge, resulting in limited discriminant power. In contrast, face is a distinct pattern much easier to capture, which motivates us to incorporate a vector-boosted multi-view face detector (C. Huang, et al., 2005) to lend strong aid to general head observation cues including color and contour edge. To simultaneously and collaboratively perform temporal inference of both the face state and the head state, a Markov-network-based particle filter is constructed using sequential belief propagation Monte Carlo (G. Hua, et al., 2004). Our approach is tested on sequences used by previous researchers as well as on new data sets which includes many challenging real-world cases, and shows robustness against various unfavorable conditions
14562465
Bioinformatics on Embedded Systems: A Case Study of Computational Biology Applications on VLIW Architecture
Bioinformatics applications represent the increasingly important workloads. Their characteristics and implications on the underlying hardware design, however, are largely unknown. Currently, biological data processing ubiquitously relies on the high-end systems equipped with expensive, general-purpose processors. The future generation of bioinformatics requires the more flexible and cost-effective computing platforms to meet its rapidly growing market. The programmable, application-specific embedded systems appear to be an attractive solution in terms of easy of programming, design cost, power, portability and time-to-market. The first step towards such systems is to characterize bioinformatics applications on the target architecture. Such studies can help in understanding the design issues and the trade-offs in specializing hardware and software systems to meet the needs of bioinformatics market. This paper evaluates several representative bioinformatics tools on the VLIW based embedded systems. We investigate the basic characteristics of the benchmarks, impact of function units, the efficiency of VLIW execution, cache behavior and the impact of compiler optimizations. The architectural implications observed from this study can be applied to the design optimizations. To the best of our knowledge, this is one of the first such studies that have ever been attempted.