35,455 research outputs found
A Framework for Evaluating Model-Driven Self-adaptive Software Systems
In the last few years, Model Driven Development (MDD), Component-based
Software Development (CBSD), and context-oriented software have become
interesting alternatives for the design and construction of self-adaptive
software systems. In general, the ultimate goal of these technologies is to be
able to reduce development costs and effort, while improving the modularity,
flexibility, adaptability, and reliability of software systems. An analysis of
these technologies shows them all to include the principle of the separation of
concerns, and their further integration is a key factor to obtaining
high-quality and self-adaptable software systems. Each technology identifies
different concerns and deals with them separately in order to specify the
design of the self-adaptive applications, and, at the same time, support
software with adaptability and context-awareness. This research studies the
development methodologies that employ the principles of model-driven
development in building self-adaptive software systems. To this aim, this
article proposes an evaluation framework for analysing and evaluating the
features of model-driven approaches and their ability to support software with
self-adaptability and dependability in highly dynamic contextual environment.
Such evaluation framework can facilitate the software developers on selecting a
development methodology that suits their software requirements and reduces the
development effort of building self-adaptive software systems. This study
highlights the major drawbacks of the propped model-driven approaches in the
related works, and emphasise on considering the volatile aspects of
self-adaptive software in the analysis, design and implementation phases of the
development methodologies. In addition, we argue that the development
methodologies should leave the selection of modelling languages and modelling
tools to the software developers.Comment: model-driven architecture, COP, AOP, component composition,
self-adaptive application, context oriented software developmen
Context for goal-level product line derivation
Product line engineering aims at developing a family of products and facilitating the derivation of product variants from it. Context can be a main factor in determining what products to derive. Yet, there is gap in incorporating context with variability models. We advocate that, in the first place, variability originates from human intentions and choices even before software systems are constructed, and context influences variability at this intentional level before the functional one. Thus, we propose to analyze variability at an early phase of analysis adopting the intentional ontology of goal models, and studying how context can influence such variability. Below we present a classification of variation points on goal models, analyze their relation with context, and show the process of constructing and maintaining the models. Our approach is illustrated with an example of a smarthome for people with dementia problems. 1
A Reference Framework for Variability Management of Software Product Lines
Variability management (VM) in software product line engineering (SPLE) is
introduced as an abstraction that enables the reuse and customization of
assets. VM is a complex task involving the identification, representation, and
instantiation of variability for specific products, as well as the evolution of
variability itself. This work presents a comparison and contrast between
existing VM approaches using qualitative meta-synthesis to determine the
underlying perspectives, metaphors, and concepts of existing methods. A common
frame of reference for the VM was proposed as the result of this analysis.
Putting metaphors in the context of the dimensions in which variability occurs
and identifying its key concepts provides a better understanding of its
management and enables several analyses and evaluation opportunities. Finally,
the proposed framework was evaluated using a qualitative study approach. The
results of the evaluation phase suggest that the organizations in practice only
focus on one dimension. The presented frame of reference will help the
organization to cover this gap in practice.Comment: 24 page
Spectral variability of classical T Tauri stars accreting in an unstable regime
Classical T Tauri stars (CTTSs) are variable in different time-scales. One
type of variability is possibly connected with the accretion of matter through
the Rayleigh-Taylor instability that occurs at the interface between an
accretion disc and a stellar magnetosphere. In this regime, matter accretes in
several temporarily formed accretion streams or `tongues' which appear in
random locations, and produce stochastic photometric and line variability. We
use the results of global three-dimensional magnetohydrodynamic simulations of
matter flows in both stable and unstable accretion regimes to calculate
time-dependent hydrogen line profiles and study their variability behaviours.
In the stable regime, some hydrogen lines (e.g. H-beta, H-gamma, H-delta,
Pa-beta and Br-gamma) show a redshifted absorption component only during a
fraction of a stellar rotation period, and its occurrence is periodic. However,
in the unstable regime, the redshifted absorption component is present rather
persistently during a whole stellar rotation cycle, and its strength varies
non-periodically. In the stable regime, an ordered accretion funnel stream
passes across the line of sight to an observer only once per stellar rotation
period while in the unstable regime, several accreting streams/tongues, which
are formed randomly, pass across the line of sight to an observer. The latter
results in the quasi-stationarity appearance of the redshifted absorption
despite the strongly unstable nature of the accretion. In the unstable regime,
multiple hot spots form on the surface of the star, producing the stochastic
light curve with several peaks per rotation period. This study suggests a CTTS
that exhibits a stochastic light curve and a stochastic line variability, with
a rather persistent redshifted absorption component, may be accreting in the
unstable accretion regime.Comment: 20 pages, 11 figures, 1 table, accepted for publication in MNRA
Managing Process Variants in the Process Life Cycle
When designing process-aware information systems, often variants of the same process have to be specified. Each variant then constitutes an adjustment of a particular process to specific requirements building the process context. Current Business Process Management (BPM) tools do not adequately support the management of process variants. Usually, the variants have to be kept in separate process models. This leads to huge modeling and maintenance efforts. In particular, more fundamental process changes (e.g., changes of legal regulations) often require the adjustment of all process variants derived from the same process; i.e., the variants have to be adapted separately to meet the new requirements. This redundancy in modeling and adapting process variants is both time consuming and error-prone. This paper presents the Provop approach, which provides a more flexible solution for managing process variants in the process life cycle. In particular, process variants can be configured out of a basic process following an operational approach; i.e., a specific variant is derived from the basic process by applying a set of well-defined change operations to it. Provop provides full process life cycle support and allows for flexible process configuration resulting in a maintainable collection of process variants
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