一种新的在线调度算法竞争比分析方法——基于实例转换的方法

针对工件动态到达的在线调度模型提出了一种基于实例转换的竞争分析方法,该方法从问题的一个任意实例出发,逐步沿着性能比增加的方向修改工件的各种参数而得到结构更加简单特殊的实例,最后所导出的简单实例的性能比可以直接计算,且是算法竞争比的一个上界.该方法为在线调度算法的竞争比分析提供了一种新颖的、规律性的思路,以最小化总加权完工时间的单机在线调度问题为例,使用提出的分析方法为该问题一个已有的竞争分析结论提供了更加简洁明了的替代性证明.

A NOVEL WAY TO ANALYZE COMPETITIVE PERFORMANCE OF ONLINE ALGORITHMS-INSTANCE TRANSFORMATION BASED METHOD

A competitive analysis method for online algorithms is developed based on the idea of instance transformation. The method begins with an arbitrary instance, and transforms the instance along the direction of its performance ratio increasing, moreover the eventual instance after transformation shows a more special structure of which we can take advantage to analyze its performance ratio. This presented method is applied on a single machine online scheduling problem of minimizing the total weighted completion time. We give an alternative proof of an existing conclusion about the competitive performance.