In the past two decades, the use of ontologies has grown accompanied by a diversity in ontological representations and applications to more comprehensive domains. Knowledge engineers have found it expeditious to break down large (monolithic) ontologies to work with smaller fragments. Ontology modularization is the process of extracting a fragment, or "module", from an ontology, based on predefined requirements. Due to both the diversity in ontological representations and motivations for modularizing, the body of research on ontology modularization techniques has become extremely large and may be intimidating to the novice ontology researcher. The objective of the paper is to present a comprehensive, albeit high-level, review of ontology modularization techniques. A systematic literature review covering January 1st 2000 to July 31st 2020 was performed to find and classify papers on ontology modularization techniques. The techniques exhibiting certain properties with respect to several features were assessed, and the modularization techniques were classified with a multi-dimensional perspective. The classifications are intended to guide one to a suitable modularization process in accordance with the requirements. The limitations of ontology modularization techniques are highlighted in the conclusion, and characteristics of a desirable framework for an ontology representation that would be best-suited for modularization are presented.

Software Product Line deals with the development of product families for diverse market needs and includes feature model to describe the structure of the included products. Since feature model is lack of detailed specification of individual features, some behavior-oriented methods have been proposed to analyze the inner functionalities of features. But how these functions relate to the feature model remains a problem and a systematic approach is still needed to support the whole process of product family modeling. This paper provides a formal engineering approach to modeling product family where feature model evolves as individual features are formalized through informal, semi-formal and formal stages. For each stage, a set of evolvement rules are given to guide the refactoring of the feature model which will then serve as a basis for formal specifications of individual features. Such an iterative process repeats until achieving a feature model with consistent feature specifications. A case study is described to illustrate the effectiveness of our approach.

This paper formalizes the graphical modularization technique, View Traversal, for an ontology-based system represented using the Domain Information System (DIS). Our work is motivated by the need for autonomous agents, within an ontology-based system, to automatically create their own views of the ontology to address the problems of ontology evolution and data integration found in an enterprise setting. Through DIS, we explore specific ontologies that give Cartesian perspectives of the domain, which allows modularization to be a means for agents to extract views of specific combinations of data. The theory of ideals from Boolean algebra is used to formalize a module. Then, with the use of homomorphisms, the quantity of knowledge within the module can be measured. More specifically, through the first isomorphism theorem, we establish that the loss of information is quantified by the kernel of the homomorphism. This constitutes a foundational step towards theories related to reasoning on partial domain knowledge, and is important for applications where an agent needs to quickly extract a view that contains a specific set of knowledge.

Several organizations generate and store a wide range of information in what is commonly referred to as data stores. To access the information within these data stores, two main architectures are widely adopted. The first architecture gives access to information through a trusted server that enforces established confidentiality policies. The second one allows the information to be public but in its encrypted form. Then through a scheme for the distribution of cryptographic keys, each user is provided with the keys needed to decrypt only the part of the information she is authorized to access. This paper relates to the latter architecture. We introduce an algebraic framework that takes into consideration a new perspective in tackling the key-distribution problem. We use the proposed framework to analyze key-distribution schemes that are representative of the ones found in the literature. The framework enables the specification and the verification of key-distribution policies. We also point to several other applications related to measures ensuring information confidentiality.

Embedded systems such as automotive systems are very complex to specify. Since it is difficult to capture all their requirements or their design in one single model, approaches working with several system views are adopted. The main problem there is to keep these views coherent; the issue is known as view reconciliation. This paper proposes an algebraic solution. It uses sets of integration constraints that link (families of) system features in one view to other (families of) features in the same or a different view. Both, families and constraints, are formalised using a feature algebra. Besides presenting a constraint relation and its mathematical properties, the paper shows in several examples the suitability of this approach for a wide class of integration constraint formulations.

We give a formal relation-based definition of scenarios and we show how different scenarios can be integrated to obtain a more global view of user-system interactions. We restrict ourselves to the sequential case, meaning that we suppose that there is only one user (thus, the scenarios we wish to integrate cannot occur concurrently). Our view of scenarios is state-based, rather than event-based, like most of the other approaches, and can be grafted to the well-established specification language Z. Also, the end product of scenario integration, the specification of the functional aspects of the system, is given as a relation; this specification can be refined using independently developed methods. Our formal description is coupled with a diagram-based, transition-system like, presentation of scenarios, which is better suited to communication between clients and specifiers.