Browsing by Subject "Computer software--Development."

Now showing 1 - 3 of 3

Open Access
Analysis and design of scalable software as a service architecture
(2015) Özcan, Onur
Different from traditional enterprise applications that rely on the infrastructure and services provided and controlled within an enterprise, cloud computing is based on services that are hosted on providers over the Internet. Hereby, services are fully managed by the provider, whereas consumers can acquire the required amount of services on demand, use applications without installation and access their personal files through any computer with internet access. Recently, a growing interest in cloud computing can be observed thanks to the significant developments in virtualization and distributed computing, as well as improved access to high-speed Internet and the need for economical optimization of resources. An important category of cloud computing is the software as a service domain in which software applications are provided over the cloud. In general when describing SaaS, no specific application architecture is prescribed but rather the general components and structure is defined. Based on the provided reference SaaS architecture different application SaaS architectures can be derived each of which will typically perform differently with respect to different quality factors. An important quality factor in designing SaaS architectures is scalability. Scalability is the ability of a system to handle a growing amount of work in a capable manner or its ability to be enlarged to accommodate that growth. In this thesis we provide a systematic modeling and design approach for designing scalable SaaS architectures. To identify the aspects that impact the scalability of SaaS based systems we have conducted a systematic literature review in which we have identified and analyzed the relevant primary studies that discuss scalability of SaaS systems. Our study has yielded the aspects that need to be considered when designing scalable systems. Our research has continued in two subsequent directions. Firstly, we have defined a UML profile for supporting the modeling of scalable SaaS architectures. The profile has been defined in accordance with the existing practices on defining and documenting profiles. Secondly, we provide the socalled architecture design perspective for designing scalable SaaS systems. Architectural Perspectives are a collection of activities, tactics and guidelines to modify a set of existing views, to document and analyze quality properties. Architectural perspectives as such are basically guidelines that work on multiple views together. So far architecture perspectives have been defined for several quality factors such as for performance, reuse and security. However, an architecture perspective dedicated for designing scalable SaaS systems has not been defined explicitly. The architecture perspective that we have defined considers the scalability aspects derived from the systematic literature review as well as the architectural design tactics that represent important proved design rules and practices. Further, the architecture perspective adopts the UML profile for scalability that we have defined. The scalability perspective is illustrated for the design of a SaaS architecture for a real industrial case study.
Open Access
Architectural viewpoints for global software development
(2011) Yıldız, Buğra Mehmet
Current trends in software engineering show that large software projects have to operate with teams that are working in different locations. The reason behind this globalization of software development stems from clear business goals such as reducing cost of development, solving local IT skills shortage, and supporting outsourcing and offshoring. There is ample reason that these factors will be even stronger in the future, and as such we will face a further globalization of software development. To cope with these problems, the concept of Global Software Development (GSD) is introduced. GSD is a relatively new concept in software development that can be considered as the coordinated activity of software development that is not localized and central but geographically distributed. Designing a proper architecture of GSD is important to meet the requirements for the communication, coordination and control of distributed GSD teams. However, an analysis of the literature on GSD shows that research in this area has been generally focused on social issues focusing on some concerns such as intercultural communication problems and coordination. It is generally accepted that software architecture design plays a fundamental role in coping with the inherent difficulties of the development of large-scale and complex software. Unfortunately, in both GSD and software architecture design communities, the architecture design of GSD systems has not been explicitly addressed. This study aims to provide a contribution in this context by explicitly focusing on the architecture design of GSD. A common practice is to model and document different architectural views for describing the architecture according to the stakeholders’ concerns. Having multiple views helps to separate the concerns and as such support the modeling, understanding, communication and analysis of the software architecture for different stakeholders. Architectural views conform to viewpoints that represent the conventions for constructing and using a view. In this study, we propose seven architectural viewpoints which have been specifically defined for modeling GSD architecture. To define architecture viewpoints, we first describe a general GSD meta-model. The metamodel has been derived after a thorough analysis of the related GSD literature. The meta-model consists of six different parts which form the abstract syntax of the architectural viewpoints. After the meta-model derivation, we also suggest textual and visual concrete syntaxes for the meta-model in order to complete viewpoint definition. Supporting the architect in deriving architectural views based on the corresponding architectural viewpoints, we present a question framework. The question framework consists of six sets of questions related to the key concerns of a GSD project. Based on the answers given to the questions in this framework, the GSD application architecture can be derived by applying predefined design actions in the question framework. We have developed the tool called Global Architect which implements the question framework. Global Architect takes as input the answers to the provided questions and subsequently generates the textual architecture description of the required viewpoint. On its turn, the textual description is used to generate the visual presentation of the application architecture for the GSD project.
Open Access
Slicing approach to specification for testability in LOTOS
(1993) Ateş, Ahmet Feyzi
With the recent increase in the use of formal methods in specification of communication protocols, there is a need to base the conformance testing of protocol implementations on formal specifications. This brings in the problem of finding out special design issues to be used in the specification of such systems that facilitate test generation. This aspect is called Specification For Testability, and it is investigated in this study for the particular formal description technique LOTOS. Specification for testability is approached from the perspective of designing formal base protocol specifications, and then deriving functional specifications from base specifications in order to use in test generation. The method utilized for the derivation of functional specifications is Ccdled slicing. As inspired from previous work in software engineering, slices of protocol specifications are obtained systematically according to the hierarchically designed test suite structures, where each slice corresponds to a particular tunction of the protocol, and subsequent test generation is based on the obtained slices. The techni(|ues developed are demonstrated on the simple state-oriented specifications of INRES and ACSE protocols along with a real base specification of the OSI Transport Protocol written in the constraintoriented specification style. The results indicate that tests derived from functional specifications have some remarkable properties with respect to test case analysis and representation.