30994252
An extension of a theorem on cycles containing specified independent edges
We give an alternative proof of a conjecture due to Wang (J. Graph Theory 26 (1997) 105) in a stronger form. The main theorem states that for any integer k ≥ 2 if G is a graph of order n ≥ 4k - 1 and d(u) + d(υ) ≥ n + 2k - 2 for each pair of non-adjacent vertices u and υ of G, then, for any k independent edges e1,... ,ek of G, there exist k vertex-disjoint cycles C1,..., Ck in G such that (i) ei ∈ E(Ci) for all 1 ≤ i ≤ k, (ii) V(C1)∪ ... ∪V(Ck) = V(G), and (iii) #{i ≤ k||Ci| a > n - 4k + 2). It strengthens the conjecture of Wang, which was first proven by Egawa et al. (Graphs Combin. 16 (2000) 81).
43797306
On the Maximum Number of Independent Cycles in a Bipartite Graph
LetG=(V1, V2; E) be a bipartite graph with |V1|=|V2|=n?2k, wherekis a positive integer. Suppose that the minimum degree ofGis at leastk+1. We show that ifn>2k, thenGcontainskvertex-disjoint cycles. We also show that ifn=2k, thenGcontainsk?1 quadrilaterals and a path of order 4 such that all of them are vertex-disjoint. Moreover, the condition on degrees is sharp. We conjecture that whenn=2k,Gindeed containskvertex-disjoint quadrilaterals.
28783158
Directed Bipartite Graphs Containing Every Possible Pair of Directed Cycles
43159264
P2p-factorization of a complete bipartite graph
206077177
Pentagons and cycle coverings
Let G be a graph of order n ≥ 5k + 2, where k is a positive integer. Suppose that the minimum degree of G is at least (n + k)/2 . We show that G contains k pentagons and a path such that they are vertexdisjoint and cover all the vertices of G. Moreover, if n ≥ 5k + 7, then G contains k + 1 vertex-disjoint cycles covering all the vertices of G such that k of them are pentagons. © 2006 Wiley Periodicals, Inc. J Graph Theory 54: 194–208, 2007
39356858
Vertex-disjoint quadrilaterals in graphs
Let k be a positive integer and G a graph of order n. In (Discrete Math. 203 (1999) 229), we proved that if n=4k and @d(G)>=2k then G contains k-1 vertex-disjoint quadrilaterals. In this paper, we investigate vertex-disjoint quadrilaterals in G with n@?0(mod4), and we have found the best minimum degree condition @d(G)>=@?12n@? such that G contains @?14n@? vertex-disjoint quadrilaterals. As a result of our method, we have improved our previous result as follows: If n=4k and @d(G)>=2k-1 then G contains k-1 vertex-disjoint quadrilaterals.
40482370
Quantitative evaluation of the register stack engine and optimizations for future Itanium processors
This paper examines the efficiency of the register stack engine (RSE) in the canonical Itanium architecture, and introduces novel optimization techniques to enhance the RSE performance. To minimize spills and fills of the physical register file, optimizations are applied to reduce internal fragmentation in statically allocated register stack frames. Through the use of dynamic register usage (DRU) and dead register value information (DVI), the processor can dynamically guide allocation and deallocation of register frames. Consequently, a speculatively allocated register frame with a dynamically determined frame size can be much smaller than the statically determined frame size, thus achieving minimum spills and fills. Using the register stack engine (RSE) in the canonical Itanium architecture as the baseline reference, we thoroughly study and gauge the tradeoffs of the RSE and the proposed optimizations using a set of SPEC CPU2000 benchmarks built with different compiler optimizations. A combination of frame allocation policies using the most frequent frame size and deallocation policies using dead register information proves to be highly effective. On average, a 71% reduction in aggregate spills and fills can be achieved over the baseline reference.
7007458
An Algorithm for Identification of Reduced-Order Dynamic Models of Gas Turbines
Model based approaches show a lot of advantages for fault detection and condition monitoring. Particularly, it is true in employing reduced order models for real-time parameter identification and output prediction of gas turbines. Many algorithms have been developed, but most of them focus on one-step-ahead prediction models and involve complex computation. These algorithms are not acceptable for long-term prediction and real-time condition monitoring. In this paper, an improved gradient method (dynamic gradient descent) is proposed. The idea is to take account of the dependency of prediction errors and calculate the gradient information recursively. Not only low computation expense is achieved, but the non-Gaussian errors can also be overcome when this approach is applied to estimate parameters of a reduced order gas turbine model and to improve long-term prediction
29063745
A New Graph Approach to Minimizing Processor Fragmentation in Hypercube Multiprocessors
The authors propose a new approach for subcube and noncubic processor allocations for hypercube multiprocessors. The main idea is to represent available processors in the system by means of a prime cube graph (PC-graph). The PC-graph maintains the inter-relationships between free subcubes and hence reduces both internal and external processor fragmentations. Their simulation results show that the PC-graph approach outperforms the existing allocation strategies by 25% to 50% under certain load conditions. >
35232295
Implementing a scalable ASC processor
Previous papers (Walker et al. (2001); Wu et al. (2002)) have described our implementation of a small prototype processor and control unit for associative computing, called the ASC processor. That initial prototype was implemented on an Altera education board using an Altera FLEX 10K FPGA, and was limited to an unrealistic 4 processing elements (PE). This paper describes a more complete implementation - a scalable ASC processor that can scale up to 52 PE on an Altera APEX 20KE board, or further on larger FPGA. This paper also proposes extensions to support multiple control units and control parallelism.
424163
Reliable Observer-Based Control Against Sensor Failures for Systems With Time Delays in Both State and Input
For systems with both state and input time delays, a novel state and sensor fault observer is proposed in this paper to estimate system states and sensor faults simultaneously. In this design, a descriptor system approach and a linear matrix inequality technique are adopted, where the considered sensor fault may be in any form, even unbounded. Unbounded sensor faults will make the system fail unavoidably; it is indispensable to derive a reliable control scheme against sensor failures. Using the estimated state and sensor fault, a reliable observer-based controller is proposed, which makes the system work well no matter whether sensor faults occur or not. The present approaches are next extended to the case for systems with multiple time delays. Finally, a simulation example of the network of three cascaded reactors is used to illustrate the design procedure and demonstrate the efficiency of the present techniques.