Models are often used to represent various types of systems. This is especially true for software systems, where cooperating teams create models using a modeling language (e.g., UML). In cooperative modeling scenarios, it is useful to identify contributions and changes performed by individuals and teams. This paper presents a technique called CHECKSUM, which monitors the cooperative work done on models and maintains an immutable changelog. CHECKSUM uses its changelog to measure contributions based on points, time, and quality, and to enable the auditing of a model’s change-history. This paper also presents GEneric Meta-Model (GEMM). The latter unifies the underlying representation of different types of models that follow varying visualization patterns including box and line, container, and interleaving. GEMM enables CHECKSUM to support an extensible variety of model types. We developed a prototype tool that realizes CHECKSUM’s concepts and integrates it into two existing modeling tools. We conducted two studies to evaluate CHECKSUM from two perspectives: technical and user. The studies yielded positive results concerning various qualities including integrability into existing tools, effectiveness, efficiency, usability, and usefulness.

模型通常用于表示各种类型的系统。对于软件系统而言尤其如此，在软件系统中，合作团队使用建模语言（例如UML）创建模型。在协作建模方案中，识别个人和团队所做的贡献和更改非常有用。本文提出了一种称为CHECKSUM的技术，该技术监视在模型上完成的协作工作并维护不变的变更日志。CHECKSUM使用其变更日志来基于点，时间和质量来评估贡献，并能够审计模型的变更历史。本文还介绍了GEneric元模型（GEMM）。后者统一了遵循不同可视化模式（包括框和线，容器和交错）的不同类型模型的基础表示。GEMM使CHECKSUM支持广泛的模型类型。我们开发了一个原型工具，该工具实现了CHECKSUM的概念，并将其集成到两个现有的建模工具中。我们进行了两项研究，从技术和用户两个角度评估CHECKSUM。这些研究在各种质量方面取得了积极的成果，包括与现有工具的可集成性，有效性，效率，可用性和实用性。