Thèse de doctorat : Università della Svizzera italiana, 2009 ; 2009INFO002.
Performance and high-availability are the crucial factors in the development of nowadays distributed database systems. Both of these challenges are commonly addressed by means of the same technique, database replication. The overall throughput of the system is increased by leveraging parallel computation on different sites, and in case of replica failures, availability is improved by...
|
Thèse de doctorat : Università della Svizzera italiana, 2009 ; 2009INFO003.
Approximation algorithms are motivated by the fact that for many important optimization problems we cannot hope to efficiently find an optimal solution (unless P=NP). Instead, we have to settle for second best — a solution that is close to being optimal. A natural question that arises is: how close to the optimal solution can one get with an efficient algorithm? The past two decades have...
|
Thèse de doctorat : Università della Svizzera italiana, 2009 ; 2009INFO001.
Wireless sensor networks (WSNs) are a fast developing research area with many new exciting applications arising, ranging from micro climate and environmental monitoring through health and structural monitoring to interplanetary communications. At the same time researchers have invested a lot of time and effort into developing high performance energy efficient and reliable communication protocols...
|
Thèse de doctorat : Università della Svizzera italiana, 2008 ; 2008INFO004.
Software changes. Any long-lived software system has maintenance costs dominating its initial development costs as it is adapted to new or changing requirements. Systems on which such continuous changes are performed inevitably decay, making each maintenance task harder. This problem is not new: The software evolution research community has been tackling it for more than two decades. However,...
|
Thèse de doctorat : Università della Svizzera italiana, 2008 ; 2008INFO003.
Credal networks are probabilistic graphical models that extend Bayesian nets to deal with imprecision in probability, and can actually be regarded as sets of Bayesian nets. Credal nets appear to be powerful means to represent and deal with many important and challenging problems in uncertain reasoning. The counterpart of having more freedom in the modeling phase is an increased inferential...
|
Middleware-based database replication protocols require few or no changes in the database engine. As a consequence, they are more portable and flexible than kernel-based protocols, but have coarser-grain information about transaction access data, resulting in reduced concurrency and increased aborts. This paper proposes conflict-aware load-balancing techniques to increase the concurrency and...
|
Thèse de doctorat : Università della Svizzera italiana, 2005 ; 2005COM004.
A common opinion in the Requirements Traceability field is that solution design, i.e. the design of the application solutions, may be derived directly from requirements refinement; according to current industrial practices and to some specific experiences, this dissertation proposes a different thesis: the design process is not a fully rational and explicit sequence of actions; designers keep...
|
Thèse de doctorat : Università della Svizzera italiana, 2006 ; 2006COM002.
Communication is virtually impossible when interlocutors lack the ability to negotiate meanings. The intended semantics of the language used by a sender should be perceived and mastered by its receiver/s. For this reason the sender should always vision and identify himself in the receiver in order to design the most clear and proper signs with respect to her/his knowledge. Web sites are complex...
|
In this paper, the system is viewed as a construction based on the actors’ cognitive and social interactions. The system is the result of multiple – actor sense making (Weick 1995), but at the same time it orients social sense making. In this process each actor’s point of view is a representation of both the system and the context perceived as pertinent by the actor. In other words, the...
|
Thèse de doctorat : Università della Svizzera italiana, 2003.
Lo sviluppo di applicazioni web necessita di strumenti efficaci per gestire alcuni aspetti essenziali del processo di analisi dei requisiti: l'identificazione di obiettivi di comunicazione strategici, la presenza di una varietà di profili utente e di stakeholders, le definizione di requisiti ipermediali (riguardanti navigazione, interazione, contenuto e presentazione), e il riuso dei requisiti...
|
