Modelling languages are frequently extended to include new constructs to be used together with the original syntax. New constructs may be proposed by adding textual information, such as UML stereotypes, or by creating new graphical representations. Thus, these new symbols need to be expressive and proposed in a careful way to increase the extension’s adoption. A method to create symbols for the original constructs of a modelling language was proposed and has been used to create the symbols when a new modelling language is designed. We argue this method can be used to recommend new symbols for the extension’s constructs. However, it is necessary to make some adjustments since the new symbols will be used with the existing constructs of the modelling language original syntax. In this paper, we analyse the usage of this adapted method to propose symbols to mitigate the occurrence of overloaded symbols in the existing iStar extensions. We analysed the existing iStar extensions in an SLR and identified the occurrence of symbol overload among the existing constructs. We identified a set of fifteen overloaded symbols in existing iStar extensions. We used these concepts with symbol overload in a multi-stage experiment that involved users in the visual notation design process. The study involved 262 participants, and its results revealed that most of the new graphical representations were better than those proposed by the extensions, with regard to semantic transparency. Thus, the new representations can be used to mitigate this kind of conflict in iStar extensions. Our results suggest that next extension efforts should consider user-generated notation design techniques in order to increase the semantic transparency.

中文翻译：

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使用经验研究减轻iStar扩展中的符号过载

建模语言经常被扩展为包括与原始语法一起使用的新构造。通过添加文本信息（例如UML原型）或创建新的图形表示，可以提出新的构造。因此，这些新符号需要富有表现力，并应以谨慎的方式提出，以增加扩展名的采用率。提出了一种为建模语言的原始构造创建符号的方法，并已在设计新的建模语言时用于创建符号。我们认为此方法可用于为扩展的结构推荐新的符号。但是，由于新符号将与建模语言原始语法的现有构造一起使用，因此必须进行一些调整。在本文中，我们分析了这种改编方法的用法，以提出符号来减轻现有iStar扩展中过载符号的发生。我们分析了SLR中现有的iStar扩展，并确定了现有结构中符号重载的发生。我们在现有的iStar扩展中识别出15个重载符号集。在涉及用户的视觉符号设计过程的多阶段实验中，我们将这些概念与符号过载一起使用。这项研究涉及262名参与者，其结果表明，在语义透明性方面，大多数新的图形表示均优于扩展所提出的图形表示。因此，新的表示形式可用于减轻iStar扩展中的此类冲突。