Tight bounds for NF-based bounded-space online bin packing algorithms

In Zheng et al. (J Comb Optim 30(2):360–369, 2015) modelled a surgery problem by the one-dimensional bin packing, and developed a semi-online algorithm to give an efficient feasible solution. In their algorithm they used a buffer to temporarily store items, having a possibility to lookahead in the list. Because of the considered practical problem they investigated the 2-parametric case, when the size of the items is at most 1/2. Using an NF-based online algorithm the authors proved an ACR of 13/9 = 1.44 … for any given buffer size not less than 1. They also gave a lower bound of 4/3 = 1.33 … for the bounded-space algorithms that use NF-based rules. Later, in Zhang et al. (J Comb Optim 33(2):530–542, 2017) an algorithm was given with an ACR of 1.4243, and the authors improved the lower bound to 1.4230. In this paper we present a tight lower bound of h∞ (r) for the r-parametric problem when the buffer capacity is 3. Since h∞ (2) = 1.42312 …, our result—as a special case—gives a tight bound for the algorithm-class given in 2017. To prove that the lower bound is tight, we present an NF-based online algorithm that considers the r-parametric problem, and uses a buffer with capacity of 3. We prove that this algorithm has an ACR that is equal to the lower bounds for arbitrary r. © Springer Science+Business Media, LLC 2017

Lower bound for 3-batched bin packing

Abstract In this paper we will consider a special relaxation of the well-known online bin packing problem. In a batched bin packing problem (BBPP)–defined by Gutin et al. (2005)–the elements come in batches and one batch is available for packing in a given time. If we have K ≥ 2 batches then we denote the problem by K -BBPP. In Gutin et al. (2005) the authors gave a 1.3871 … lower bound for the asymptotic competitive ratio (ACR) of any on-line 2 -BBBP algorithm. In this paper we investigate the 3-BBPP, and we give 1.51211 … lower bound for its ACR

Ládapakolások átpakolással

In contrast to on-line bin packing, semi-on-line bin-packing allows the algorithm to carry out extra operations, in addition to the packing of the actual element, in each step of the process. These extra operations might include at least one of the following operations: repacking, reordering or buffering. This paper defines and analyses a semi-on-line bin-packing problem, where repacking is allowed, but only for a restricted number of elements. We provide lower and upper bounds for the problem, and lower bounds for some special cases of the problem. The lower bounds also apply to some related problems