<p>It is not unusual that software systems are redeveloped when the systems environment changes or new requirements to functionality are found. The reason for this is that system evolution is usually not considered during the initial development of a system.</p><p>In this report we propose a development process focusing on modifiability in security-safety critical systems. The process is based on the standard IEC 61508 Functional safety of electrical/electronic/programmable electronic safety-related systems and the CORAS framework for model-based risk assessment. We focus on integrating modifiability as a non-functionality and extend the development process with an architecture and design phase. Modifiability is addressed using Architecture Tradeoff Analysis Method (ATAM) and Attribute Driven Design (ADD). An evaluation of this process is given by redeveloping a prototype for an already existing security-critical system using the approaches given by the process. The main result from the evaluation showed that we where able to obtain a higher level of modifiability than the original prototype, without compromising the functionality and safety level required.</p>

It is not unusual that software systems are redeveloped when the systems environment changes or new requirements to functionality are found. The reason for this is that system evolution is usually not considered during the initial development of a system. In this report we propose a development process focusing on modifiability in security-safety critical systems. The process is based on the standard IEC 61508 Functional safety of electrical/electronic/programmable electronic safety-related systems and the CORAS framework for model-based risk assessment. We focus on integrating modifiability as a non-functionality and extend the development process with an architecture and design phase. Modifiability is addressed using Architecture Tradeoff Analysis Method (ATAM) and Attribute Driven Design (ADD). An evaluation of this process is given by redeveloping a prototype for an already existing security-critical system using the approaches given by the process. The main result from the evaluation showed that we where able to obtain a higher level of modifiability than the original prototype, without compromising the functionality and safety level required.

[Truncated abstract] In this thesis, we introduce a mammogram analysis system developed for the automatic segmentation and analysis of mammograms. This original system has been designed to aid radiologists to detect breast cancer on mammograms. The system embodies attribute-driven segmentation in which the attributes of an image are extracted progressively in a step-by-step, hierarchical fashion. Global, low-level attributes obtained in the early stages are used to derive local, high-level attributes in later stages, leading to increasing refinement and accuracy in image segmentation and analysis. The proposed system can be characterized as: • a bootstrap engine driven by the attributes of the images; • a solid framework supporting the process of hierarchical segmentation; • a universal platform for the development and integration of segmentation and analysis techniques; and • an extensible database in which knowledge about the image is accumulated. Central to this system are three major components: 1. a series of applications for attribute acquisition; 2. a standard format for attribute normalization; and 3. a database for attribute storage and data exchange between applications. The first step of the automatic process is to segment the mammogram hierarchically into several distinctive regions that represent the anatomy of the breast. The adequacy and quality of the mammogram are then assessed using the anatomical features obtained from segmentation. Further image analysis, such as breast density classification and lesion detection, may then be carried out inside the breast region. Several domain-specific algorithms have therefore been developed for the attribute acquisition component in the system. These include: 1. automatic pectoral muscle segmentation; 2. adequacy assessment of positioning and exposure; and 3. contrast enhancement of mass lesions. An adaptive algorithm is described for automatic segmentation of the pectoral muscle on mammograms of mediolateral oblique (MLO) views

Den här uppsatsen behandlar skapandet och designen av en arkitektur över ett system för behandling av depression och andra psykiska sjukdomar via internet, kallat Melencolia. Ett av kraven för detta projekt är att skapa ett system som kan utökas i framtiden. Vi har härlett detta krav till begreppet modularitet och för att skapa en modulär arkitektur för Melencolia har vi undersökt vad begreppet innebär och härlett det till att vara ett kvalitetsdrag hos flera kvalitetsattribut däribland ”maintainability” och ”reusability”. Med hjälp av ”Attribute Driven Design” kan en arkitektur skapas som fokuserar kring en viss typ av kvalitetsattribut. Eftersom modularitet inte är ett kvalitetsattribut utan en kvalitetsegenskap har vi varit tvungna att ändra indata till denna metod, från kvalitetsattribut till kvalitetsegenskap. Vidare har vi härlett och lagt fram en ny metod för att mäta kvalitetsegenskaper i en mjukvaruarkikektur.Slutligen har vi använt vår metod för att mäta graden av modularitet i Melencolias arkitektur. / This thesis considers the problem of creating and designing an architecture for a software project that will result in a system for treatment of depression on the Internet. One of the requirements for this project, named by Melencolia, is to create a system which can be extended in the future. From this requirement we have derived the concept of modularity. In order to create a modular architecture we have concluded that modularity is a quality characteristic of multiple quality attributes such as "maintainability" and "reusability".We deploy Attribute-Driven Design (ADD) in this Melencolia project. By doing this, an architecture that is focused around modularity can be created. Since modularity is not a quality attribute, but rather a quality characteristic, we had to change the input to ADD from a quality attribute to a quality characteristic.Furthermore, we derive and propose a new method for quality characteristic evaluation of software architectures.Finally we apply our aforementioned method on the architecture of Melencolia and by doing this we get an indication on how well our proposed architecture satisfies modularity.