Byungchun Chung

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The value of hysteresis has a significant effect on the handover performance measured in terms of the handover initiation delay and the number of handovers. To determine the hysteresis value effectively, a mobility correlation among users is utilized. In this letter, a grouping algorithm and an adaptive hysteresis algorithm based on the mobility correlation(More)
This paper describes a new accumulate-and-add multiplication algorithm. The method partitions one of the operands and re-combines the results of computations done with each of the partitions. The resulting design turns-out to be both compact and fast. When the operands’ bit-lengthm is 1024, the new algorithm requires only 0.194m+56 additions (on average),(More)
Zhu proposed a Synchro-Difference LKH scheme for secure multicast that appeared in IEEE Communications Letters, vol. 9, no. 5, pp. 477–479, May 2005, which is an enhancement of the well-known LKH scheme. In this letter, we show that Zhu’s scheme is insecure against collusion of two or more malicious adversaries by presenting two kinds of attack scenarios.
An improved base-f expansion method is proposed, in which the bit-length of coefficients is shorter and the number of coefficients is smaller than in Kobayashi’s expansion method. The proposed method meshes well with efficient multi-exponentiation algorithms. In addition, two efficient algorithms based on the proposed expansion method, named f-wNAF and(More)
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