5 research outputs found
AIUCD 2022 - Proceedings
L’undicesima edizione del Convegno Nazionale dell’AIUCD-Associazione di Informatica Umanistica ha per titolo Culture digitali. Intersezioni: filosofia, arti, media. Nel titolo è presente, in maniera esplicita, la richiesta di una riflessione, metodologica e teorica, sull’interrelazione tra tecnologie digitali, scienze dell’informazione, discipline filosofiche, mondo delle arti e cultural studies
Experimental Evaluation of Growing and Pruning Hyper Basis Function Neural Networks Trained with Extended Information Filter
In this paper we test Extended Information Filter (EIF) for sequential training of Hyper Basis Function Neural Networks with growing and pruning ability (HBF-GP). The HBF neuron allows different scaling of input dimensions to provide better generalization property when dealing with complex nonlinear problems in engineering practice. The main intuition behind HBF is in generalization of Gaussian type of neuron that applies Mahalanobis-like distance as a distance metrics between input training sample and prototype vector. We exploit concept of neuron’s significance and allow growing and pruning of HBF neurons during sequential learning process. From engineer’s perspective, EIF is attractive for training of neural networks because it allows a designer to have scarce initial knowledge of the system/problem. Extensive experimental study shows that HBF neural network trained with EIF achieves same prediction error and compactness of network topology when compared to EKF, but without the need to know initial state uncertainty, which is its main advantage over EKF
Bioinspired metaheuristic algorithms for global optimization
This paper presents concise comparison study of newly developed bioinspired algorithms for global optimization problems. Three different metaheuristic techniques, namely Accelerated Particle Swarm Optimization (APSO), Firefly Algorithm (FA), and Grey Wolf Optimizer (GWO) are investigated and implemented in Matlab environment. These methods are compared on four unimodal and multimodal nonlinear functions in order to find global optimum values. Computational results indicate that GWO outperforms other intelligent techniques, and that all aforementioned algorithms can be successfully used for optimization of continuous functions
Data Management Strategies for Relative Quality of Service in Virtualised Storage Systems
The amount of data managed by organisations continues to grow relentlessly.
Driven by the high costs of maintaining multiple local storage systems, there
is a well established trend towards storage consolidation using multi-tier Virtualised Storage Systems (VSSs). At the same time, storage infrastructures
are increasingly subject to stringent Quality of Service (QoS) demands.
Within a VSS, it is challenging to match desired QoS with delivered QoS,
considering the latter can vary dramatically both across and within tiers.
Manual efforts to achieve this match require extensive and ongoing human
intervention. Automated efforts are based on workload analysis, which ignores
the business importance of infrequently accessed data.
This thesis presents our design, implementation and evaluation of data
maintenance strategies in an enhanced version of the popular Linux Extended
3 Filesystem which features support for the elegant specification
of QoS metadata while maintaining compatibility with stock kernels. Users
and applications specify QoS requirements using a chmod-like interface. System
administrators are provided with a character device kernel interface
that allows for profiling of the QoS delivered by the underlying storage. We
propose a novel score-based metric, together with associated visualisation
resources, to evaluate the degree of QoS matching achieved by any given
data layout. We also design and implement new inode and datablock allocation
and migration strategies which exploit this metric in seeking to match
the QoS attributes set by users and/or applications on files and directories
with the QoS actually delivered by each of the filesystem’s block groups.
To create realistic test filesystems we have included QoS metadata support
in the Impressions benchmarking framework. The effectiveness of the
resulting data layout in terms of QoS matching is evaluated using a special
kernel module that is capable of inspecting detailed filesystem data on-the-fly.
We show that our implementations of the proposed inode and datablock
allocation strategies are capable of dramatically improving data placement
with respect to QoS requirements when compared to the default allocators
An Embedded Domain Specific Language to Model, Transform and Quality Assure Business Processes in Business-Driven Development
Business process models are produced by business analysts to graphically communicate the business requirements to IT specialists. As business processes are updated to meet the new demands in the competitive market, the underlying IT solution is adapted, to reflect precisely the current goals of the organisation. The models should then act as an abstract representation of the solution. It is essential to adapt to Business-Driven Development (BDD), whereby models are refined into the IT solution and implemented in a Service-Oriented Architecture. This means that models must be free from data and control-flow errors, such as deadlocks. If models are not quality assured at the modelling phase, errors would be discovered later and the entire BDD lifecycle would have to be repeated. Combining model transformations with quality assurance would help modellers to preserve the correctness of models and rapidly carry out modifications.
Although various modelling languages have been developed to assist modellers in the production of high quality business process models, none of them adopted a functional approach, based on higher-order logic. As BDD is being adopted by most organisations, the need for such a language is becoming more evident. Since specialized functionality is required, a general-purpose language is not really necessary. Instead, a domain-specific language which provides the right abstraction and captures precisely the semantics of the business process modelling domain, should be developed. The definitions of the models would be easy to comprehend and reason about, by anyone who is not necessarily an IT specialist. However, since languages are made up of domain independent and dependent linguistic components, it is more cost effective and feasible to embed the new language in a general-purpose language.
In this project we present a domain specific language embedded in the functional language, Haskell, to model, transform and quality assure business processes in Business-Driven Development. By adopting a functional approach, we developed a language: 1) with which various models can rapidly be produced in a concise and abstract manner, 2) allows users to focus on the required behaviour rather than its implementation, 3) ensures that all the required details, to generate the executable code, are specified, 4) the abstract representation can be interpreted, analysed and transformed in various ways, 5) quality assures models by carrying out three types of checks; by Haskell’s type checker, at construction-time through our embedded type system, and by specialised functions that analyse the components in the model.
By embedding our language in Haskell, the models, quality assurance checks and transformations are essentially functions which can easily be composed and defined. Connection patterns, defined in the language, play an important role to ensure that definitions are concise, readable and easy to comprehend. Different from other previous modelling tools, users are able to define their own parameterized models and transformations. By generating a directed graph for the models, various types of analysis can be carried out with greater ease. Moreover, quality assurance can be combined to model transformations by declaratively defining pre and post conditions for each transformation. These conditions as well as transformations can easily be composed of other previously defined checks or transformations.
With this language, we aim to capture the domain semantics of IBM’s WebSphere Business Modeler Advanced v6.0.2