8,994 research outputs found
Search based software engineering: Trends, techniques and applications
© ACM, 2012. This is the author's version of the work. It is posted here by permission of ACM for your personal use. Not for redistribution. The definitive version is available from the link below.In the past five years there has been a dramatic increase in work on Search-Based Software Engineering (SBSE), an approach to Software Engineering (SE) in which Search-Based Optimization (SBO) algorithms are used to address problems in SE. SBSE has been applied to problems throughout the SE lifecycle, from requirements and project planning to maintenance and reengineering. The approach is attractive because it offers a suite of adaptive automated and semiautomated solutions in situations typified by large complex problem spaces with multiple competing and conflicting objectives.
This article provides a review and classification of literature on SBSE. The work identifies research trends and relationships between the techniques applied and the applications to which they have been applied and highlights gaps in the literature and avenues for further research.EPSRC and E
Mixing multi-core CPUs and GPUs for scientific simulation software
Recent technological and economic developments have led to widespread availability of
multi-core CPUs and specialist accelerator processors such as graphical processing units
(GPUs). The accelerated computational performance possible from these devices can be very
high for some applications paradigms. Software languages and systems such as NVIDIA's
CUDA and Khronos consortium's open compute language (OpenCL) support a number of
individual parallel application programming paradigms. To scale up the performance of some
complex systems simulations, a hybrid of multi-core CPUs for coarse-grained parallelism and
very many core GPUs for data parallelism is necessary. We describe our use of hybrid applica-
tions using threading approaches and multi-core CPUs to control independent GPU devices.
We present speed-up data and discuss multi-threading software issues for the applications
level programmer and o er some suggested areas for language development and integration
between coarse-grained and ne-grained multi-thread systems. We discuss results from three
common simulation algorithmic areas including: partial di erential equations; graph cluster
metric calculations and random number generation. We report on programming experiences
and selected performance for these algorithms on: single and multiple GPUs; multi-core CPUs;
a CellBE; and using OpenCL. We discuss programmer usability issues and the outlook and
trends in multi-core programming for scienti c applications developers
Feature-based methodology for supporting architecture refactoring and maintenance of long-life software systems
Zusammenfassung
Langlebige Software-Systeme durchlaufen viele bedeutende Veraenderungen im Laufe ihres Lebenszyklus,
um der Weiterentwicklung der Problemdomaenen zu folgen. Normalerweise ist es schwierig eine
Software-Systemarchitektur den schnellen Weiterentwicklungen einer Problemdomaene anzupassen und
mit der Zeit wird der Unterschied zwischen der Problemdomaene und der Software-Systemarchitektur
zu groß, um weitere Softwareentwicklung sinnvoll fortzufuehren. Fristgerechte Refactorings der Systemarchitektur
sind notwendig, um dieses Problem zu vermeiden.
Aufgrund des verhaeltnismaeßig hohen Gefahrenpotenzials und des zeitlich stark verzoegerten Nutzens
von Refactorings, werden diese Maßnahmen normalerweise bis zum letztmoeglichen Zeitpunkt hinausgeschoben.
In der Regel ist das Management abgeneigt Architektur-Refactorings zu akzeptieren,
außer diese sind absolut notwendig. Die bevorzugte Vorgehensweise ist, neue Systemmerkmale ad hoc
hinzuzufuegen und nach dem Motto ”Aendere nie etwas an einem funktionierenden System!” vorzugehen.
Letztlich ist das Ergebnis ein Architekturzerfall (Architekturdrift). Die Notwendigkeit kleiner
Refactoring-Schritte fuehrt zur Notwendigkeit des Architektur-Reengineerings. Im Gegensatz zum
Refactoring, das eine normale Entwicklungstaetigkeit darstellt, ist Reengineering eine Form der Software-
”Revolution”. Reengineeringprojekte sind sehr riskant und kostspielig. Der Nutzen des Reengineerings
ist normalerweise nicht so hoch wie erwartet. Wenn nach dem Reengineering schließlich die erforderlichen
Architekturaenderungen statt.nden, kann dies zu spaet sein. Trotz der enormen in das Projekt
gesteckten Bemuehungen erfuellen die Resultate des Reengineerings normalerweise nicht die Erwartungen.
Es kann passieren, dass sehr bald ein neues, kostspieliges Reengineering erforderlich wird.
In dieser Arbeit werden das Problem der Softwareevolution und der Zerfall von Softwarearchitekturen
behandelt. Eine Methode wird vorgestellt, welche die Softwareentwicklung in ihrer entscheidenden
Phase, dem Architekturrefactoring, unterstuetzt. Die Softwareentwicklung wird sowohl in technischer
als auch organisatorischer Hinsicht unterstuetzt. Diese Arbeit hat neue Techniken entwickelt,
welche die Reverse-Engineering-, Architecture-Recovery- und Architecture-Redesign-Taetigkeiten unterst
uetzen. Sie schlaegt auch Aenderungen des Softwareentwicklungsprozesses vor, die fristgerechte Architekturrefactorings
erzwingen koennen und damit die Notwendigkeit der Durchfuehrung eines Architektur-
Reengineerings vermeiden.
In dieser Arbeit wird die Merkmalmodellierung als Hauptinstrument verwendet. Merkmale werden
genutzt, um die Abstraktionsluecke zwischen den Anforderungen der Problemdomaene und der Systemarchitektur
zu fuellen. Merkmalmodelle werden auch als erster Grundriss fr die Wiederherstellung
der verlorenen Systemarchitektur genutzt. Merkmalbasierte Analysen fuehren zu diversen, nuetzlichen
Hinweisen fuer den erneuten Entwurf (das Re-Design) einer Architektur. Schließlich wird die Merkmalmodellierung
als Kommunikationsmittel zwischen unterschiedlichen Projektbeteiligten (Stakeholdern)
im Verlauf des Softwareengineering-Prozesses verwendet und auf dieser Grundlage wird ein neuer
Anforderungsde.nitionsprozess vorgeschlagen, der die erforderlichen Architekturrefactorings erzwingt.The long-life software systems withstand many significant changes throughout their life-cycle in order
to follow the evolution of the problem domains. Usually, the software system architecture can not
follow the rapid evolution of a problem domain and with time, the diversion of the architecture in
respect to the domain features becomes prohibiting for software evolution. For avoiding this problem,
periodical refactorings of the system architecture are required.
Usually, architecture refactorings are postponed until the very last moment, because of the relatively
high risk involved and the lack of short-term profit. As a rule, the management is unwilling to accept
architecture refactorings unless they become absolutely necessary. The preferred way of working is to
add new system features in an ad-hoc manner and to keep the rule ”Never touch a running system!”.
The final result is an architecture decay. The need of performing small refactoring activities turns into
need for architecture reengineering. In contrast to refactoring, which is a normal evolutionary activity,
reengineering is a kind of software ”revolution”. Reengineering projects are risky and expensive. The
effectiveness of reengineering is also usually not as high as expected. When finally after reengineering
the required architecture changes take place, it can be too late. Despite the enormous invested efforts,
the results of the reengineering usually do not satisfy the expectations. It might happen that very
soon a new expensive reengineering is required.
This thesis deals with the problem of software evolution and the decay of software architectures.
It presents a method, which assists software evolution in its crucial part, the architecture refactoring.
The assistance is performed for both technical and organizational aspects of the software evolution.
The thesis provides new techniques for supporting reverse engineering, architecture recovery and redesigning
activities. It also proposes changes to the software engineering process, which can force
timely architecture refactorings and thus avoid the need of performing architecture reengineering.
For the work in this thesis feature modeling is utilized as a main asset. Features are used to fill the
abstraction gap between domain requirements and system architecture. Feature models are also used
as an outline for recovering of lost system architectures. Through feature-based analyses a number of
useful hints and clues for architecture redesign are produced. Finally, feature modeling is used as a
communication between different stakeholders of the software engineering process and on this basis a
new requirements engineering process is proposed, which forces the needed architecture refactorings
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