A Model for Quality Optimization in Software Design Processes

The main objective of software engineers is to design and implement systems that implement all functional and non-functional requirements. Unfortunately, it is very difficult or even generally impossible to deliver a software system that satisfies all the requirements. Even more seriously, failures in fulfilling requirements are generally detected after the realization of software systems. This is because design decisions are mostly taken based on estimations, which can turn out to be wrong at a later stage in the design process. Switching to different design alternatives at a later stage can be very difficult since this may demand drastic changes in design and also may increase project time and costs. In this paper a model is proposed for modeling and tracing design processes with respect to the selected design alternatives. Based on the model, two algorithmic definitions of design strategies are given, which enable software engineers to optimize design decisions with respect to quality and resource constraints

Information Technology of Software Architecture Structural Synthesis of Information System

Information technology of information system software architecture structural synthesis is proposed. It is used for evolutionary models of the software lifecycle, which provides configuration and formation of software to control the realization and recovery of computing processes in parallel and distributed computing resources structures. The technology is applied in the framework of the software requirements analysis, design of architecture, design and integration of software. Method of combining vertices for multilevel graph model of software architecture and automata-based method of checking performance limitations to software are based on the advanced graph model of software architecture. These methods are proposed in the framework of information technology and allow forming a rational structure of the program, as well as checking for compliance with the functional and non-functional requirements of the end user.The essence of proposed information technology is in displaying of the customer's requirements in the current version of the graph model of program complex structure and providing a reconfiguration of the system modules. This process is based on the analysis and processing of the graph model, software module specifications, formation of software structure in accordance with the graph model, software verification and its compilation

On Model Based Synthesis of Embedded Control Software

Many Embedded Systems are indeed Software Based Control Systems (SBCSs), that is control systems whose controller consists of control software running on a microcontroller device. This motivates investigation on Formal Model Based Design approaches for control software. Given the formal model of a plant as a Discrete Time Linear Hybrid System and the implementation specifications (that is, number of bits in the Analog-to-Digital (AD) conversion) correct-by-construction control software can be automatically generated from System Level Formal Specifications of the closed loop system (that is, safety and liveness requirements), by computing a suitable finite abstraction of the plant. With respect to given implementation specifications, the automatically generated code implements a time optimal control strategy (in terms of set-up time), has a Worst Case Execution Time linear in the number of AD bits $b$, but unfortunately, its size grows exponentially with respect to $b$. In many embedded systems, there are severe restrictions on the computational resources (such as memory or computational power) available to microcontroller devices. This paper addresses model based synthesis of control software by trading system level non-functional requirements (such us optimal set-up time, ripple) with software non-functional requirements (its footprint). Our experimental results show the effectiveness of our approach: for the inverted pendulum benchmark, by using a quantization schema with 12 bits, the size of the small controller is less than 6% of the size of the time optimal one.Comment: Accepted for publication by EMSOFT 2012. arXiv admin note: substantial text overlap with arXiv:1107.5638,arXiv:1207.409

EVALUATION OF CAPTURING ARCHITECTURALLY SIGNIFICANT REQUIREMENTS METHODS

Every software development organization strives for customer satisfaction. It is universally accepted that the success of software development lies in the clear understanding of the client requirements. During requirement elicitation and analysis stage, the system analyst identifies the functional and non-functional requirements from the customer. Security, usability, reliability, performance, scalability and supportability are the significant quality attributes of a software system. These quality attributes are also referred as non-functional requirements. Only a few functional and quality attributes requirement help to identify and shape the software architecture. A software system's architecture is the set of prime design decisions made about the system. If the requirement influences the architectural design decision then, it is referred as Architecturally Significant Requirement (ASR). Identifying and specifying all the possible ASR are important tasks in the requirement elicitation and analysis stage.In this research, general problems that are faced while capturing and specifying ASR in requirement elicitation and analysis is studied. Among the different requirement elicitation techniques, use case diagram has been identified and enhanced to solve the problem of capturing and specifying ASR during the requirement elicitation and analysis phase Â&nbsp

Old Wine in New Skins? Revisiting the Software Architecture for IP Network Stacks on Constrained IoT Devices

In this paper, we argue that existing concepts for the design and implementation of network stacks for constrained devices do not comply with the requirements of current and upcoming Internet of Things (IoT) use cases. The IoT requires not only a lightweight but also a modular network stack, based on standards. We discuss functional and non-functional requirements for the software architecture of the network stack on constrained IoT devices. Then, revisiting concepts from the early Internet as well as current implementations, we propose a future-proof alternative to existing IoT network stack architectures, and provide an initial evaluation of this proposal based on its implementation running on top of state-of-the-art IoT operating system and hardware.Comment: 6 pages, 2 figures and table

The convenience for a notation to express non-functional characteristics of software components

Software systems are characterised both by their functionality (what the system does) and by their non-functionality (how does the system behave with respect to some observable attributes like performance, reusability, reliability, etc.). Both aspects are relevant to software development. However, non-functional issues have received little attention compared to functional ones. In this position paper we highlight the role of non-functionality, and we claim for a notation to deal with them. We enumerate some design principles for such a notation, and then we make a proposal, which allows to de ne non-functional attributes of software, non-functional behaviour of components with respect to these attributes, and also non-functional requirements over implementations.Peer ReviewedPostprint (author's final draft