Input-output conformance simulation (iocos) has been proposed by Gregorio-Rodr\'iguez, Llana and Mart\'inez-Torres as a simulation-based behavioural preorder underlying model-based testing. This relation is inspired by Tretmans' classic ioco relation, but has better worst-case complexity than ioco and supports stepwise refinement. The goal of this paper is to develop the theory of iocos by studying logical characterisations of this relation, rule formats for it and its compositionality. More specifically, this article presents characterisations of iocos in terms of modal logics and compares them with an existing logical characterisation for ioco proposed by Beohar and Mousavi. It also offers a characteristic-formula construction for iocos over finite processes in an extension of the proposed modal logics with greatest fixed points. A precongruence rule format for iocos and a rule format ensuring that operations take quiescence properly into account are also given. Both rule formats are based on the GSOS format by Bloom, Istrail and Meyer. The general modal decomposition methodology of Fokkink and van Glabbeek is used to show how to check the satisfaction of properties expressed in the logic for iocos in a compositional way for operations specified by rules in the precongruence rule format for iocos .

翻译：输入输出符合模拟（iocos）由Gregorio-Rodríguez、Llana和Martínez-Torres提出，是一种基于模拟的行为预序关系，用于模型驱动测试。该关系受Tretmans经典ioco关系启发，但相比ioco具有更优的最坏情况复杂性，并支持逐步精化。本文旨在通过研究iocos关系的逻辑表征、规则格式及其组合性来发展其理论体系。具体而言，本文首先从模态逻辑角度给出iocos的表征，并与Beohar和Mousavi提出的ioco现有逻辑表征进行对比；其次，针对有限进程构建了基于所提模态逻辑（扩展了最大不动点）的特征公式；随后提出了iocos的预同余规则格式，以及确保操作正确考虑静默态的规则格式。两种规则格式均基于Bloom、Istrail和Meyer的GSOS格式。最后，利用Fokkink和van Glabbeek的通用模态分解方法，展示了如何以组合方式验证由iocos预同余规则格式指定的操作是否满足相关逻辑性质。