Browsing by Author "Kuo, YC"

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A laboratory study on the undrained strength of a silty sand from Central Western Taiwan
(2004-10-01)
Huang, YT
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Huang, AB
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Kuo, YC
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Tsai, MD
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土木工程學系
The sand deposit in Central Western Taiwan typically contained significant amounts of fines. The assessment of liquefaction potential using the simplified procedure often involved adjustment in field test results to account for the effects of fines. The available fines content (FC) adjustment methods are highly empirical and may lead to very different conclusions. The need and/or level of FC adjustment should be justified based on cyclic behavior of sand and its relationship with fines. This study made an attempt to provide that reference information for a silty sand commonly found in Central Western Taiwan. A series of isotropic consolidation, undrained monotonic and cyclic triaxial tests were conducted on reconstituted Mai Liao Sand (MLS) with various FCs and densities. Concurrent shear wave velocities were measured using bender elements in some of the cyclic triaxial tests. This paper describes the geological background, the laboratory tests and their implications in the assessment of liquefaction potential for MLS. (C) 2004 Published by Elsevier Ltd.
Packet-based scheduling algorithm for CIOQ switches with multiple traffic classes
(2005-07-18)
Lee, TH
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Kuo, YC
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傳播研究所
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Institute of Communication Studies
A packet-based least cushion first/most urgent first (PB-LCF/MUF) maximal matching algorithm is presented in this paper for combined input and output queued (CIOQ) switches with multiple traffic classes. The main benefit of using a CIOQ switch is to alleviate memory bandwidth requirement while providing quality of service (QoS) guarantee. It was proved that, with a speedup factor of 2, a CIOQ switch which adopts the LCF/MUF scheduling algorithm can exactly emulate an output queued (OQ) switch for any service discipline under fixed-length packets assumption. However, in current Internet environment, packets are transported with different lengths. Therefore, it is necessary to modify the LCF/MUF scheduling algorithm for variable-length packet traffic. For case of implementation, the proposed algorithm calculates approximate cushions and does not perform re-ordering at output ports. We found, via computer simulations, that the performance of a CIOQ switch with a speedup factor of 5 that adopts the proposed single-iteration PB-LCF/MUF algorithm is close to that of an OQ switch under the weighted round robin service discipline for offered traffic load up to 0.9. In addition, the packet departure order can be maintained under the single-iteration algorithm. (c) 2005 Elsevier B.V. All rights reserved.
Parallel matching algorithm for CIOQ switches with multiple traffic classes
(2003-10-01)
Lee, TH
;
Kuo, YC
;
傳播研究所
;
Institute of Communication Studies
It has recently been shown that a combined input and output queued (CIOQ) switch with a speed-up factor of 2 can exactly emulate an output-queued (OQ) switch. The main benefit of using a CIOQ switch is to reduce memory bandwidth requirement while providing quality of service (QoS) guarantee. The key component for exact emulation is a matching algorithm for bipartite graphs. For example, a CIOQ switch with a speed-up factor of 2, which adopts the least cushion first/most urgent first (LCF/MUF) matching algorithm, can exactly emulate an OQ switch with any arbitrary service discipline. However, the complexities of cushion calculation and cell reordering required at the output ports make the algorithm very difficult to be realised in a highspeed switch. The authors propose an approximate LCF/MUF algorithm and evaluate its performance for the weighted round-robin service discipline. For ease of implementation, the proposed algorithm calculates approximate cushions and does not perform reordering at the output ports. The trade-off is that it loses the property of exact emulation. It was found, via computer simulations, that the performance of a CIOQ switch with the proposed single-iteration matching algorithm is close to that of an OQ switch under uniform, nonuniform, and correlated input traffic models for offered load up to 0.9. In addition, the cell departure order can be maintained under the single-iteration algorithm.