Due to the Semantic Web’s decentralised nature, ontology engineers rarely know all applications that leverage their ontology. Consequently, they are unaware of the full extent of possible consequences that changes might cause to the ontology. Our goal is to lessen the gap between ontology engineers and users by investigating ontology engineers’ understanding of ontology changes’ impact at editing time. Hence, this paper introduces the Protégé plugin ChImp which we use to reach our goal. We elicited requirements for ChImp through a questionnaire with ontology engineers. We then developed ChImp according to these requirements and it displays all changes of a given session and provides selected information on said changes and their effects. For each change, it computes a number of metrics on both the ontology and its materialisation. It displays those metrics on both the originally loaded ontology at the beginning of the editing session and the current state to help ontology engineers understand the impact of their changes.

We investigated the informativeness of materialisation impact measures, the meaning of severe impact, and also the usefulness of ChImp in an online user study with 36 ontology engineers. We asked the participants to solve two ontology engineering tasks – with and without ChImp (assigned in random order) – and answer in-depth questions about the applied changes as well as the materialisation impact measures. We found that ChImp increased the participants’ understanding of change effects and that they felt better informed. Answers also suggest that the proposed measures were useful and informative. We also learned that the participants consider different outcomes of changes severe, but most would define severity based on the amount of changes to the materialisation compared to its size. The participants also acknowledged the importance of quantifying the impact of changes and that the study will affect their approach of editing ontologies.

由于语义网的去中心化性质，本体工程师很少知道利用其本体的所有应用程序。因此，他们不知道变化可能对本体造成的全部后果。我们的目标是通过调查本体工程师对本体更改在编辑时的影响的理解来缩小本体工程师和用户之间的差距。因此，本文介绍了我们用来实现目标的 Protégé 插件 ChImp。我们通过对本体工程师的问卷调查得出了对 ChImp 的要求。然后，我们根据这些要求开发了 ChImp，它显示给定会话的所有更改，并提供有关所述更改及其影响的选定信息。对于每次更改，它都会计算一些关于本体及其具体化的指标。

我们在与 36 位本体工程师的在线用户研究中调查了物化影响措施的信息量、严重影响的含义以及 ChImp 的有用性。我们要求参与者解决两个本体工程任务——使用和不使用 ChImp（以随机顺序分配）——并回答有关应用更改以及物化影响措施的深入问题。我们发现 ChImp 增加了参与者对变化影响的理解，并且他们感觉自己更了解情况。答复还表明，提议的措施是有用的和信息丰富的。我们还了解到，参与者认为变化的不同结果是严重的，但大多数人会根据物化的变化量与其大小相比来定义严重性。