Orthogonal Variability Model Research Articles

A Product Line Systems Engineering Process for Variability Identification and Reduction

Software Product Line Engineering has attracted attention in the last two decades due to its promising capabilities to reduce costs and time to market through reuse of requirements and components. In practice, developing system level product lines in a large-scale company is not an easy task as there may be thousands of variants and multiple disciplines involved. The manual reuse of legacy system models at domain engineering to build reusable system libraries and configurations of variants to derive target products can be infeasible. To tackle this challenge, a Product Line Systems Engineering process is proposed. Specifically, the process extends research in the System Orthogonal Variability Model to support hierarchical variability modeling with formal definitions; utilizes Systems Engineering concepts and legacy system models to build the hierarchy for the variability model and to identify essential relations between variants; and finally, analyzes the identified relations to reduce the number of variation points. The process, which is automated by computational algorithms, is demonstrated through an illustrative example on generalized Rolls-Royce aircraft engine control systems. To evaluate the effectiveness of the process in the reduction of variation points, it is further applied to case studies in different engineering domains at different levels of complexity. Subject to system model availability, reduction of 14% to 40% in the number of variation points are demonstrated in the case studies.

Decision‐Driven Product Development

ABSTRACTProduct line engineering (PLE) is the engineering and management of a group of related products using a shared set of assets and a means of design and manufacturing. PLE can include systems, software, and assets and involves all aspects of engineering including electrical, electronic, mechanical, and chemical, just to name a few. Engineers normally consider PLE after the product has evolved and complexity becomes too much to manage. Leveraging PLE from the very beginning will identify cost savings and commonality and provide a natural means for product evolution. Orthogonal variability modeling (OVM) provides a natural decision set allowing engineers to perform trade‐offs for specific customers and guide system development along the most effective route. Using automotive examples, this paper will describe model‐based product line engineering (MB‐PLE), the process for creating product lines, and the benefits of this approach as applicable to the military ground vehicle domain. Finally, it will show how the adoption of MB‐PLE early in the development life cycle provides more benefits without the potential disruption and reengineering that can occur when engineers adopt it later in the life cycle.

Evaluating the Importance of Analyzability, Testability and Changeability Quality Attribute in Reference to Software Product Line Orthogonal Variability Model

In Software Engineering, quality evaluation is very difficult task because of complexity of software systems. For this purpose the evaluation of quality attributes is very important concept with reference to Software Product Line Orthogonal Variability Model. Identifying whether the Orthogonal Variability Model is easy to analyze, test and change will help to develop a successful product line. Three important sub characteristics of Maintainability i.e. Analyzability, Testability and Changeability play a greater role in development of successful product line. This paper is intended to study the role of Analyzability, Testability and Changeability quality attributes over Orthogonal Variability Models.

Decision‐Driven Product Development

AbstractProduct Line Engineering (PLE) is the engineering and management of a group of related products using a shared set of assets and a means of design and manufacturing. PLE can include system and software, assets and involves all aspects of engineering including electrical, electronic, mechanical, chemical, etc. PLE is normally considered after the product has evolved and complexity becomes too much to manage. Leveraging PLE from the very beginning will identify cost savings and commonality and provide a natural means for product evolution. Orthogonal Variability Modeling (OVM) provides a natural decision set allowing engineers to perform trade‐offs for specific customers and guide system development along the most effective route. Using automotive examples, this paper will describe Model‐based Product Line Engineering, the process for creating product lines, and the benefits of this approach as applicable to the military ground vehicle domain. Finally, it will show how the adoption of MB‐PLE early on in the development lifecycle provides more benefits without the potential disruption and re‐engineering that can be involved when it is adopted later on in the lifecycle.

Variability Change Management Using the Orthogonal Variability Model-Based Traceability

Variability is the ability of a software system or artifacts to be changed, customized, or configured for reuse in the product members of a software product line. As the amount of variability increases in software product lines the complexity of managing changes and evolutions of such variability becomes a main concern these days. In this context a high-degree of traceability can support the complexity of variability change management. However, in software product line establishing appropriate traceability is often difficult due to many-to-many relations in different levels of abstraction and across development given two separated and closely related development life cycles called domain and application. This paper proposes an approach tracing variability based on explicit variation points defined in orthogonal variability model and domain artifacts. And we validate the proposed approach through the Calculator product line. As the results of validation we found that our approach supports the defined variability change scenarios well, but has a disadvantage that many derived variation points are additionally defined and managed.

Variability Modeling for Customizable Saas Applications

Most of current Software-as-a-Service (SaaS) applications are developed as customizable service-oriented applications that serve a large number of tenants (users) by one application instance. The current rapid evolution of SaaS applications increases the demand to study the commonality and variability in software product lines that produce customizable SaaS applications. During runtime, Customizability is required to achieve different tenants' requirements. During the development process, defining and realizing commonalty and variability in SaaS applications' families is required to develop reusable, flexible, and customizable SaaS applications at lower costs, in shorter time, and with higher quality. In this paper, Orthogonal Variability Model (OVM) is used to model variability in a separated model, which is used to generate simple and understandable customization model. Additionally, Service oriented architecture Modeling Language (SoaML) is extended to define and realize commonalty and variability during the development of SaaS applications.

A Systems Approach to Product Line Requirements Reuse

Product line engineering has become the main method for achieving systematic software reuse. Embracing requirements in a product line's asset base enhances the effectiveness of reuse as engineers can work on the abstractions closer to the domain's initial concepts. Conventional proactive approaches to product line engineering cause excessive overhead when codifying the assets. In this paper, we propose a systems-oriented approach to extracting functional requirements profiles. The validated extraction constructs are amenable to semantic case analysis and orthogonal variability modeling, so as to uncover the variation structure and constraints. To evaluate our approach, we present an experiment to quantify the extraction overhead and effectiveness and a case study to assess our approach's usefulness. The results show that our automatic support offers an order-of-magnitude saving over the manual extraction effort without significantly compromising quality and that our approach receives a positive adoption rate by systems engineers.

Feature Modeling and Variability Modeling Syntactic Notation Comparison and Mapping

Feature Model (FM) became an important role in Software Product Line Engineering (SPLE) field. Many approaches have been introduced since the original FM came up with Feature Oriented Domain Analysis (FODA) introduced by Kang in 1990. The main purpose of FM is used for commonality and variability analysis in domain engineering, to optimize the reusable aspect of software features or components. Cardinality-based Feature Model (CBFM) is one extension of original FM, which integrates several notations of other extensions. In CBFM, feature model defined as hierarchy of feature, with each of feature has a cardinality. The other notation to express variability within SPLE is Orthogonal Variability Model (OVM). At the other hand, OMG as standard organization makes an effort to build standard generic language to express the commonality and variability in SPL field, by initiate Common Variability Language (CVL). This paper reports the comparison and mapping of FODA, CBFM and OVM to CVL where need to be explored first to define meta model mapping of these several approaches. Furthermore, the comparison and mapping of those approaches are discussed in term of R3ST (read as “REST”) software feature model as the case study.

소프트웨어 프로덕트라인 가변성 기술 기법: OVDL

소프트웨어 프로덕트라인에서 가변성은 프로덕트라인의 멤버제품들을 차별화하는 특성으로, 가변성의 기술은 의미가 명확하고 선택이 용이하도록 가시화되어야 하며 관리하기 용이하여야 한다. 가변성 기술은 크게 개발 모델에 통합하는 방법과 개발 모델과는 독립적으로 기술하는 방법으로 나눌 수 있다. OVDL (Orthogonal Variability Description Language)은 독립적 가변성 기술 방법이면서 타 방법들의 가지는 의미의 모호성을 개선하기 위하여 제안된 가변성 표현 언어이다. 이 논문은 독립적 가변성 기술 방법의 기반을 제공한 OVM (Orthogonal Variability Model)으로 기술된 IWF (Inter-Working Function) 프로덕트라인의 가변성이 OVDL로 번역될 수 있는지 확인하는 방식으로 OVDL의 가변성 기술 역량을 검증한다. Variability of the software product line that differentiates member products within a product line must be described with precise meaning and visualized so as easy to select. Moreover, it should be easy to manage. Variability description approaches can largely be divided into two approaches, integrated variability description approach and orthogonal variability description approach. Orthogonal Variability Description Language (OVDL) was developed for clear and precise description of variability without ambiguity. This paper validates the variability description capability of OVDL by translating the variability models of Inter-Working Function (IWF) product line described by using Orthogonal Variability Model (OVM) notations into variability descriptions in OVDL.

A Petri Net approach for representing Orthogonal Variability Models

The software product line (SPL) paradigm is used for developing software system products from a set of reusable artifacts, known as platform. The Orthogonal Variability Modeling (OVM) is a technique for representing and managing the variability and composition of those artifacts for deriving products in the SPL. Nevertheless, OVM does not support the formal analysis of the models. For example, the detection of dead artifacts (i.e., artifcats that cannot be included in any product) is an exhaustive activity which implies the verification of relationships between artifacs, artifacts parents, and so on. In this work, we introduce a Petri nets approach for representing and analyzing OVM models. The proposed net is built from elemental topologies that represents OVM concepts and relationships. Finally, we simulate the net and study their properties in order to avoid the product feasibility problems.

Quality-aware analysis in product line engineering with the orthogonal variability model

Software product line engineering is about producing a set of similar products in a certain domain. A variability model documents the variability amongst products in a product line. The specification of variability can be extended with quality information, such as measurable quality attributes (e.g., CPU and memory consumption) and constraints on these attributes (e.g., memory consumption should be in a range of values). However, the wrong use of constraints may cause anomalies in the specification which must be detected (e.g., the model could represent no products). Furthermore, based on such quality information, it is possible to carry out quality-aware analyses, i.e., the product line engineer may want to verify whether it is possible to build a product that satisfies a desired quality. The challenge for quality-aware specification and analysis is threefold. First, there should be a way to specify quality information in variability models. Second, it should be possible to detect anomalies in the variability specification associated with quality information. Third, there should be mechanisms to verify the variability model to extract useful information, such as the possibility to build a product that fulfils certain quality conditions (e.g., is there any product that requires less than 512 MB of memory?). In this article, we present an approach for quality-aware analysis in software product lines using the orthogonal variability model (OVM) to represent variability. We propose to map variability represented in the OVM associated with quality information to a constraint satisfaction problem and to use an off-the-shelf constraint programming solver to automatically perform the verification task. To illustrate our approach, we use a product line in the automotive domain which is an example that was created in a national project by a leading car company. We have developed a prototype tool named FaMa-OVM, which works as a proof of concepts. We were able to identify void models, dead and false optional elements, and check whether the product line example satisfies quality conditions.