Assisting software architects in architectural decision-making using Quark

Non-Functional Requirements (NFRs) and constraints are among the principal drivers of architectural decision-making. NFRs are improved or damaged by architectural decisions (ADs), while constraints directly include or exclude parts of the architecture (e.g., logical components or technologies). We may determine the impact of an AD, or which parts of the architecture are affected by a constraint, but at the end it is hard to know if we are respecting the NFRs and the imposed constraints with all the ADs made. In the usual approach, architects use their own experience to produce software architectures that comply with the NFRs and imposed constraints, but at the end, especially for crucial decisions, the architect has to deal with complex trade-offs between NFRs and juggle with possible incompatibilities raised by the imposed constraints. In this paper we present Quark, a method to assist software architects in architectural decision-making, and the conceptualization of the relationship between NFRs and ADs defined in Arteon, an ontology to represent and manage architectural knowledge. Finally, we provide an overview of the Quark and Arteon implementation, the ArchiTech tool.Peer ReviewedPostprint (published version

System engineering and evolution decision support, Final Progress Report (05/01/1998 - 09-30-2001)

The objective of our effort is to develop a scientific basis for system engineering automation and decision support. This objective addresses the long term goals of increasing the quality of service provided complex systems while reducing development risks, costs, and time. Our work focused on decision support for designing operations of complex modular systems that can include embedded software. Emphasis areas included engineering automation capabilities in the areas of design modifications, design records, reuse, and automatic generation of design representations such as real-time schedules and software.U.S. Army Research OfficeFunding number(s): DSAM 90387, DWAM 80013, DWAM 90215

Homomorphism between AOMRC and Hoare Model of Deterministic Reconfiguration Processes in Reconfigurable Computing Systems

In this paper, the notion of aspect-oriented modular reconfigurable computing (AOMRC) is introduced, CSP-based behaviors of AOMRC are approached by developing a model of AOMRC and constructing a Hoare model of deterministic reconfiguration processes. Then, under the theory of coalgebras, we build a homomorphism between AOMRC and a Hoare model of deterministic reconfiguration processes. In other words, since AOMRC and the Hoare model of deterministic reconfiguration processes are seen as coalgebras, their homomorphic relationship results in the behavioral equivalence between AOMRC being carried out by a transformations-based aspect and a Hoare model of deterministic reconfiguration processes

Engineering Automation for Reliable Software Interim Progress Report (10/01/2000 - 09/30/2001)

Prepared for: U.S. Army Research Office P.O. Box 12211 Research Triangle Park, NC 27709-2211The objective of our effort is to develop a scientific basis for producing reliable software that is also flexible and cost effective for the DoD distributed software domain. This objective addresses the long term goals of increasing the quality of service provided by complex systems while reducing development risks, costs, and time. Our work focuses on "wrap and glue" technology based on a domain specific distributed prototype model. The key to making the proposed approach reliable, flexible, and cost-effective is the automatic generation of glue and wrappers based on a designer's specification. The "wrap and glue" approach allows system designers to concentrate on the difficult interoperability problems and defines solutions in terms of deeper and more difficult interoperability issues, while freeing designers from implementation details. Specific research areas for the proposed effort include technology enabling rapid prototyping, inference for design checking, automatic program generation, distributed real-time scheduling, wrapper and glue technology, and reliability assessment and improvement. The proposed technology will be integrated with past research results to enable a quantum leap forward in the state of the art for rapid prototyping.U. S. Army Research Office P.O. Box 12211 Research Triangle Park, NC 27709-22110473-MA-SPApproved for public release; distribution is unlimited

Model-Driven Development of Aspect-Oriented Software Architectures

The work presented in this thesis of master is an approach that takes advantage of the Model-Driven Development approach for developing aspect-oriented software architectures. A complete MDD support for the PRISMA approach is defined by providing code generation, verification and reusability properties.Pérez Benedí, J. (2007). Model-Driven Development of Aspect-Oriented Software Architectures. http://hdl.handle.net/10251/12451Archivo delegad

System Engineering and Evolution Decision Support Interim Progress Report (01/01/2000-09/30/2000)

The objective of our effort is to develop a scientific basis for system engineering automation and decision support. This objective addresses the long term goals of increasing the quality of service provided complex systems while reducing development risks, costs, and time. Our work focused on decision support for designing operations of complex modular systems that can include embedded software. Emphasis areas included engineering automation capabilities in the areas of design modifications, design records, reuse, and automatic generation of design representations such as real-time schedules and software

A methodology for component-based system integration

Component-based software based on software architectures is emerging to be the next generation software development paradigm. The paradigm shifts the development focus from lines-of-codes to coarser-grained components and the interconnections among them. It consists of system architecture design, architecture description, component search and system integration from components to generate a software system. However, one of the bottlenecks in this paradigm is the integration of the individual components into the overall system. In this dissertation a methodology for component-based system integration is proposed. It is based on an architectural aggregation view, a component model, flowgraphs and cyclomatic complexity. We introduce this view, model, and new ways to compute cyclomatic complexity based on flowgraphs. The methodology makes use of Jackson diagram to represent the detailed design of a system and decomposes the system into components and aggregations. An aggregation is a set of components glued together by one connector, and is represented as a flowgraph. Then an aggregation flowgraph is decomposed into prime flowgraphs called prime connections. An Implementation Description Language (IDL) is introduced to represent the aggregations and components. Finally a system synthesis mechanism is proposed that is responsible for translating prime connections, embedding functional units into them, and composing aggregations and the integrated system from them

Supporting the grow-and-prune model for evolving software product lines

207 p.Software Product Lines (SPLs) aim at supporting the development of a whole family of software products through a systematic reuse of shared assets. To this end, SPL development is separated into two interrelated processes: (1) domain engineering (DE), where the scope and variability of the system is defined and reusable core-assets are developed; and (2) application engineering (AE), where products are derived by selecting core assets and resolving variability. Evolution in SPLs is considered to be more challenging than in traditional systems, as both core-assets and products need to co-evolve. The so-called grow-and-prune model has proven great flexibility to incrementally evolve an SPL by letting the products grow, and later prune the product functionalities deemed useful by refactoring and merging them back to the reusable SPL core-asset base. This Thesis aims at supporting the grow-and-prune model as for initiating and enacting the pruning. Initiating the pruning requires SPL engineers to conduct customization analysis, i.e. analyzing how products have changed the core-assets. Customization analysis aims at identifying interesting product customizations to be ported to the core-asset base. However, existing tools do not fulfill engineers needs to conduct this practice. To address this issue, this Thesis elaborates on the SPL engineers' needs when conducting customization analysis, and proposes a data-warehouse approach to help SPL engineers on the analysis. Once the interesting customizations have been identified, the pruning needs to be enacted. This means that product code needs to be ported to the core-asset realm, while products are upgraded with newer functionalities and bug-fixes available in newer core-asset releases. Herein, synchronizing both parties through sync paths is required. However, the state of-the-art tools are not tailored to SPL sync paths, and this hinders synchronizing core-assets and products. To address this issue, this Thesis proposes to leverage existing Version Control Systems (i.e. git/Github) to provide sync operations as first-class construct

Tight integration of cache, path and task-interference modeling for the analysis of hard real time systems

Traditional timing analysis for hard real-time systems is a two-step approach consisting of isolated per-task timing analysis and subsequent scheduling analysis which is conceptually entirely separated and is based only on execution time bounds of whole tasks. Today this model is outdated as it relies on technical assumptions that are not feasible on modern processor architectures any longer. The key limiting factor in this traditional model is the interfacing from micro-architectural analysis of individual tasks to scheduling analysis — in particular path analysis as the binding step between the two is a major obstacle. In this thesis, we contribute to traditional techniques that overcome this problem by means of by passing path analysis entirely, and propose a general path analysis and several derivatives to support improved interfacing. Specifically, we discuss, on the basis of a precise cache analysis, how existing metrics to bound cache-related preemption delay (CRPD) can be derived from cache representation without separate analyses, and suggest optimizations to further reduce analysis complexity and to increase accuracy. In addition, we propose two new estimation methods for CRPD based on the explicit elimination of infeasible task interference scenarios. The first one is conventional in that path analysis is ignored, the second one specifically relies on it. We formally define a general path analysis framework in accordance to the principles of program analysis — as opposed to most existing approaches that differ conceptually and therefore either increase complexity or entail inherent loss of information — and propose solutions for several problems specific to timing analysis in this context. First, we suggest new and efficient methods for loop identification. Based on this, we show how path analysis itself is applied to the traditional problem of per-task worst-case execution time bounds, define its generalization to sub-tasks, discuss several optimizations and present an efficient reference algorithm. We further propose analyses to solve related problems in this domain, such as the estimation of bounds on best-case execution times, latest execution times, maximum blocking times and execution frequencies. Finally, we then demonstrate the utility of this additional information in scheduling analysis by proposing a new CRPD bound

TOWARDS AUTOMATING POLICY- BASED MANAGEMENT SYSTEMS

The goal of distributed systems management is to provide reliable, secure and efficient utilization of the network, processors and devices that comprise those systems. The management system makes use of management agents to collect events and data from managed objects while policies provide information on how to modify the behaviour of a managed system. Systems as well as policies governing the behaviour of the system and its constituents can change dynamically. The aim of this work is to provide the services and algorithms needed to automatically identify and deploy management entities and be able to respond automatically to both changes to the system itself as well as to changes in the way the system is to be managed, i.e., changes to the set of management policies or sets of management agents. One significant challenge in the use of policy-based management systems is finding efficient mechanisms to address and simplify the gap between expressing and specifying policies and an actual configuration of a management system that realizes and makes use of policies. Little work has been done to define how the monitoring operations are to be configured and updated according to the policies. This Thesis proposes a general architecture for a policy-based management system for distributed systems which allows for expressing and automating the deployment of a wide range of management policies. The proposed solution is based on the matching between the management operations that are carried out by the management agents and the policies. The matching process relies on the attributes that the agents can monitor and the extracted attributes from the components of the policies. One major contribution of this Thesis is to build the policy model and services on existing management services found in commercial management systems. The work of this Thesis also focuses in finding87 strategies for selecting and configuring agents to be used to keep the time of a policy deployment low. The Thesis introduces the Policy-Management Agent Integrated Console (PMagic) prototype. The PMagic prototype has been implemented to provide a practical validation of the policy based management system model proposed. The approach, architecture and prototype have demonstrated that it is possible to create a more autonomic management system, particularly one that can instantiate agents to react to changes in sets of policies