Missing Requirements Information and its Impact on Software Architectures: A Case Study

[Context & motivation] In the development of large, software-intensive systems, the system’s requirements are seldom, if ever, concluded upon prior to commencing with systems architecture. Research shows that, in order to manage development and domain complexities, instances of requirements engineering (RE) and systems architecting (SA) processes tend to inter-weave. [Question/problem] However, missing requirements information can cause one to create (or recreate) the needed information during different SA activities. While backtracking in the software development process is known to be costly, the costs associated with missing requirements in the SA process have not been investigated empirically. [Principal ideas/results] We thus conducted a case study where we investigated to what extent requirements or requirements attributes’ information found missing during the SA process and impact of those missing information on SA in terms of effort. The study involved five architecting teams that involve final year undergraduate and graduate students enrolled in the university course on SA, working on architecting a system falls under “banking” domain. Our result shows that, architects did find requirements and requirements attributes’ information missing while architecting. Among requirements information, architects found that, system functionality information, constraints information and system interaction (users/systems) information are missing in requirements at higher percentages. Within requirements’ attributes, architects found requirements priority, dependency and rationale missing at higher percentages. It is also found that, out of total time spent on architecting the system, effort given to recreate missing requirements information is higher for group3 (21.5%), group1 (18%), and group2 (17%) other than group4 (12.37%) and group5(10.18%). [Contribution] The anticipated benefits of the findings are, it can motivate researchers to venture into other areas of software engineering (such as coding, testing, maintenance, etc.) from the view point of missing requirements information and its impact on those areas. This knowledge could help software practitioners to decide what kind of information need to take care of, during RE process, that could possibly ease SA process and later development phases. To the best of my knowledge, this is the first work which focuses on, to what extent requirements and requirements’ attributes information found missing during SA; characteristics and impact of those requirements missing information on SA process in terms of effort

Combining Max-Min and Max-Max Approaches for Robust SoS Architecting

A System of Systems (SoS) architecting problem requires creating a selection of systems in order to provide a set of capabilities. SoS architecting finds many applications in military/defense projects. In this paper, we study a multi-objective SoS architecting problem, where the cost of the architecture is minimized while its performance is maximized. The cost of the architecture is the summation of the costs of the systems to be included in the SoS. Similarly, the performance of the architecture is defined as the sum of the performance of the capabilities, where the performance of a capability is the sum of the selected systems\u27 contributions towards its performance. Here, nevertheless, the performance of a system in providing a capability is not known with certainty. To model this uncertainty, we assume that the performance of a system for providing a capability has lower and upper bounds and subject to complete uncertainty, i.e., no information is available about the probability distribution of the performance values. To solve the resulting multi-objective SoS architecting problem with uncertainty, we propose and compare three robust approaches: max-min, max-max, and max-mid. We apply these methods on a military example and numerically compare the results of the different approaches

Interactive A3 Architecture Overviews ☆: Intuitive Functionalities for Effective Communication

The A3 Architecture Overviews introduced earlier provide a powerful communication medium in systems engineering and architecting. Intended originally for reverse architecting, they are now also applied for designing system architectures and for systems of systems. With the current development in user interaction and touch controlled interfaces, a new means of communicating in systems engineering opens: Interactive A3 Architecture Overviews. This paper gives an overview of the state of the art of A3 Architecture Overviews before we present an investigation into interactive possibilities and an evaluation of a demonstration using a proof of concept. The results of the demonstration with several experts are listed. The main conclusion is that Interactive A3 Architecture Overviews can convey more information, without impeding usability. We end with a proposal for further developmen

Function allocation theory for creative design

Function structure influences on systems architecture (or product architecture). This paper discusses a design method for creative design solutions that focuses on the allocation of functions. It first proposes a theory called “Function Allocation Theory” to allocate a function to an appropriate subsystem or component during the systems decomposition phase. By doing so, the complexity of design solutions can be reduced. The theory is applied to some examples including collaborative robots and robotics maintenance. Finally, the paper illustrates a case study of designing a reaction-free fastening system using this theory

Thinking Tracks for Integrated Systems Design

The paper investigates systems thinking and systems engineering. After a short literature review, the paper presents, as a means for systems thinking, twelve thinking tracks. The tracks can be used as creativity starter, checklist, and as means to investigate effects of design decisions taken early in the process. Tracks include thinking about time, risk and safety, and different types of life-cycles. The thinking tracks are based on literature, teaching experience and practice as a system designer. By using the tracks a more complete picture of the system under design, the issue to be solved, the context, stakeholders and the rest of the world is created

From Monolithic Systems to Microservices: An Assessment Framework

Context. Re-architecting monolithic systems with Microservices-based architecture is a common trend. Various companies are migrating to Microservices for different reasons. However, making such an important decision like re-architecting an entire system must be based on real facts and not only on gut feelings. Objective. The goal of this work is to propose an evidence-based decision support framework for companies that need to migrate to Microservices, based on the analysis of a set of characteristics and metrics they should collect before re-architecting their monolithic system. Method. We designed this study with a mixed-methods approach combining a Systematic Mapping Study with a survey done in the form of interviews with professionals to derive the assessment framework based on Grounded Theory. Results. We identified a set consisting of information and metrics that companies can use to decide whether to migrate to Microservices or not. The proposed assessment framework, based on the aforementioned metrics, could be useful for companies if they need to migrate to Microservices and do not want to run the risk of failing to consider some important information

On Integrating Student Empirical Software Engineering Studies with Research and Teaching Goals

Background: Many empirical software engineering studies use students as subjects and are conducted as part of university courses. Aim: We aim at reporting our experiences with using guidelines for integrating empirical studies with our research and teaching goals. Method: We document our experience from conducting three studies with graduate students in two software architecture courses. Results: Our results show some problems that we faced when following the guidelines and deviations we made from the original guidelines. Conclusions: Based on our results we propose recommendations for empirical software engineering studies that are integrated in university courses.

Communication: key factor in multidisciplinary system design

System design research often looks at ways to model the system that is developing. Many modelling techniques and model representations exist. Another aspect these models can be used for is to enable, facilitate and improve communication among the developers during the process. The young System Design Group at the faculty of Engineering Technology of the University of Twente, the Netherlands, aims at focusing on this communication aspect in system design.\ud In the paper, a few finished and running projects undertaken in close cooperation with industry are described concisely. From these projects three research themes are derived. These are: creation of high-level models, combining model representations and condense information. The paper ends with plans for future research

Semantic model-driven development of web service architectures.

Building service-based architectures has become a major area of interest since the advent of Web services. Modelling these architectures is a central activity. Model-driven development is a recent approach to developing software systems based on the idea of making models the central artefacts for design representation, analysis, and code generation. We propose an ontology-based engineering methodology for semantic model-driven composition and transformation of Web service architectures. Ontology technology as a logic-based knowledge representation and reasoning framework can provide answers to the needs of sharable and reusable semantic models and descriptions needed for service engineering. Based on modelling, composition and code generation techniques for service architectures, our approach provides a methodological framework for ontology-based semantic service architecture