Web services are becoming a major utility for accomplishing complex tasks over the Internet. In practice, the end-users usually search for Web service compositions that best meet the quality of service (QoS) requirements (i.e., QoS global constraints). Since the number of services is constantly increasing and their respective QoS is inherently uncertain (due to environmental conditions), the task of selecting optimal compositions becomes more challenging. To tackle this problem, we propose a heuristic based on majority judgment that allows for reducing the search space. In addition, we perform a constraint programming search to select the Top K compositions that fulfill the QoS global constraints. The experimental results demonstrate the high performance of our approach.

中文翻译：

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基于不确定服务质量的Web服务选择与组合

Web 服务正在成为通过 Internet 完成复杂任务的主要实用程序。在实践中，最终用户通常会搜索最能满足服务质量 (QoS) 要求（即 QoS 全局约束）的 Web 服务组合。由于服务的数量不断增加，并且它们各自的 QoS 本质上是不确定的（由于环境条件），选择最佳组合的任务变得更具挑战性。为了解决这个问题，我们提出了一种基于多数判断的启发式方法，可以减少搜索空间。此外，我们执行约束编程搜索以选择满足 QoS 全局约束的 Top K 组合。实验结果证明了我们方法的高性能。