We consider the problem of nonclairvoyantly scheduling jobs, which arrive over time and have varying sizes and degrees of parallelizability, with the objective of minimizing the maximum flow. We give essentially tight bounds on the achievable competitiveness. More specifically we show that the competitive ratio of every deterministic nonclairvoyant algorithm is high, namely Ω( √ n). But there i...

Batching jobs in a manufacturing system is a very common policy in most industries. Main reasons for batching are avoidance of setups and/or facilitation of material handling. Batch processing systems often consist of multiple machines of different types for the range and volumes of products that have to be handled. Building on earlier research in aircraft industry, where the process of hardeni...

This paper investigates the impact of a vendor managed inventory (VMI) strategy upon transportation operations in a supply chain. Specifically, the issue of batching to enable better use of transport vehicles is studied. A system dynamics methodology is used to develop difference equation models of three scenarios–– traditional, internal consolidation and VMI. The holistic nature of inventory m...

Order Batching and Picker Routing Problems arise in warehouses when articles have to be retrieved from their storage location in order to satisfy a given demand specified by customer orders. The Order Batching Problem includes the grouping of a given set of customer orders into feasible picking orders such that the total length of all picker tours is minimized. The problem of determining the se...

Batching has been studied extensively in the offline case, but applications such as manufacturing or TCP acknowledgment often require online solutions. We consider online batching problems, where the order of jobs to be batched is fixed and where we seek to minimize the sum of the completion times of the jobs. We present optimally competitive online algorithms for both s-batch and p-batch probl...

This research deals with a hybrid flow shop scheduling problem with parallel batching, machine eligibility, unrelated parallel machine, and different release dates to minimize the sum of the total weighted earliness and tardiness (ET) penalties. In parallel batching situation, it is supposed that number of machine in some stages are able to perform a certain number of jobs simultaneously. First...