29 research outputs found
Multi-Criteria Optimal Planning for Energy Policies in CLP
In the policy making process a number of disparate and diverse issues such as
economic development, environmental aspects, as well as the social acceptance
of the policy, need to be considered. A single person might not have all the
required expertises, and decision support systems featuring optimization
components can help to assess policies. Leveraging on previous work on
Strategic Environmental Assessment, we developed a fully-fledged system that is
able to provide optimal plans with respect to a given objective, to perform
multi-objective optimization and provide sets of Pareto optimal plans, and to
visually compare them. Each plan is environmentally assessed and its footprint
is evaluated. The heart of the system is an application developed in a popular
Constraint Logic Programming system on the Reals sort. It has been equipped
with a web service module that can be queried through standard interfaces, and
an intuitive graphic user interface.Comment: Accepted at ICLP2014 Conference as Technical Communication, due to
appear in Theory and Practice of Logic Programming (TPLP
Monitoring Complex Processes to Verify System Conformance: A Declarative Rule-Based Framework
Over the last 60 years, computers and software have favoured incredible advancements in every field.
Nowadays, however, these systems are so complicated that it is difficult – if not challenging – to understand whether they meet some requirement or are able to show some desired behaviour or property.
This dissertation introduces a Just-In-Time (JIT) a posteriori approach to perform the conformance check to identify any deviation from the desired behaviour as soon as possible, and possibly apply some corrections.
The declarative framework that implements our approach – entirely developed on the promising open source forward-chaining Production Rule System (PRS) named Drools – consists of three components:
1. a monitoring module based on a novel, efficient implementation of Event Calculus (EC),
2. a general purpose hybrid reasoning module (the first of its genre) merging temporal, semantic, fuzzy and rule-based reasoning,
3. a logic formalism based on the concept of expectations introducing Event-Condition-Expectation rules (ECE-rules) to assess the global conformance of a system.
The framework is also accompanied by an optional module that provides Probabilistic Inductive Logic Programming (PILP).
By shifting the conformance check from after execution to just in time, this approach combines the advantages of many a posteriori and a priori methods proposed in literature.
Quite remarkably, if the corrective actions are explicitly given, the reactive nature of this methodology allows to reconcile any deviations from the desired behaviour as soon as it is detected. In conclusion, the proposed methodology brings some advancements to solve the problem of the conformance checking, helping to fill the gap between humans and the increasingly complex technology.Negli ultimi 60 anni, i computer e i programmi hanno favorito incredibili avanzamenti in ogni campo.
Oggigiorno, purtroppo, questi sistemi sono così complicati che è difficile – se non impossibile – capire se soddisfano qualche requisito o mostrano un comportamento o una proprietà desiderati.
Questa tesi introduce un approccio a posteriori Just-In-Time (JIT) per effettuare il controllo di conformità ed identificare appena possibile ogni deviazione dal comportamento desiderato, ed eventualmente applicare qualche correzione.
Il framework dichiarativo che implementa il nostro approccio – interamente sviluppato su una promettente piattaforma open source di Production Rule System (PRS) chiamata Drools – si compone di tre elementi:
1. un modulo per il monitoraggio basato su una nuova implementazione efficiente di Event Calculus (EC),
2. un modulo generale per il ragionamento ibrido (il primo del suo genere) che supporta ragionamento temporale, semantico, fuzzy e a regole,
3. un formalismo logico basato sul concetto di aspettativa che introduce le Event-Condition-Expectation rules (ECE-rules) per valutare la conformità globale di un sistema.
Il framework è anche accompagnato da un modulo opzionale che fornisce Probabilistic Inductive Logic Programming (PILP).
Spostando il controllo di conformità da dopo l’esecuzione ad appena in tempo, questo approccio combina i vantaggi di molti metodi a posteriori e a priori proposti in letteratura.
Si noti che, se le azioni correttive sono fornite esplicitamente, la natura reattiva di questo metodo consente di conciliare le deviazioni dal comportamento desiderato non appena questo viene rilevato.
In conclusione, la metodologia proposta introduce alcuni avanzamenti per risolvere il problema del controllo di conformità, contribuendo a colmare il divario tra l’uomo e la tecnologia, sempre più complessa
Hints for a general understanding of the epitaxial rules for van der Waals epitaxy from Ge-Sb-Te alloys
In this study, a generalized guideline is identified to predict the interaction between two-dimensional (2D) layered materials and substrate surfaces. Additionally, the van der Waals (vdW) heterostructures commensurability, the phase formation and the strain relaxation are identified during interface growth. To achieve such a general overview, the case of Ge-Sb-Te (GST) alloys on InAs(111) is studied. In this system, low-lattice mismatch conditions are fulfilled to avoid relaxation due to formation of misfit dislocations and allow to correctly identify vdW epitaxy. At the same time, the substrate can be efficiently prepared into self- and un-passivated surfaces to clarify the role of the surface interaction. Furthermore, the GST epilayer exhibits two different highly ordered 2D structures and a three-dimensional disordered structure, allowing to directly infer the nature of the epitaxy. This study opens the way for the design and mastering of vdW epitaxial growth of 2D heterostructures as well as hybrid 2D and non-layered materials
Interband characterization and electronic transport control of nanoscaled GeTe/SbTe superlattices
The extraordinary electronic and optical properties of the
crystal-to-amorphous transition in phase-change materials led to important
developments in memory applications. A promising outlook is offered by
nanoscaling such phase-change structures. Following this research line, we
study the interband optical transmission spectra of nanoscaled
GeTe/SbTe chalcogenide superlattice films. We determine, for films with
varying stacking sequence and growth methods, the density and scattering time
of the free electrons, and the characteristics of the valence-to-conduction
transition. It is found that the free electron density decreases with
increasing GeTe content, for sub-layer thickness below 3 nm. A simple
band model analysis suggests that GeTe and SbTe layers mix, forming a
standard GeSbTe alloy buffer layer. We show that it is possible to control the
electronic transport properties of the films by properly choosing the
deposition layer thickness and we derive a model for arbitrary film stacks
Citric acid aerospace stainless steel passivation: a green approach
Passivation is a common treatment to maximize the corrosion resistance of stainless steel. Nitric acid is generally used and involves several ecological problems, citric acid could be a promising and environmentally
friendly alternative to nitric acid. In this work citric acid has been extracted from lemon waste using and eco-
friendly procedure. The stainless steel samples have been treated in both nitric and citric acid (commercial
and extracted) and corrosion test have been performed. The results show how citric acid can be used as
substitute of nitric acid in passivation treatment
The Evolution of Compact Binary Star Systems
We review the formation and evolution of compact binary stars consisting of
white dwarfs (WDs), neutron stars (NSs), and black holes (BHs). Binary NSs and
BHs are thought to be the primary astrophysical sources of gravitational waves
(GWs) within the frequency band of ground-based detectors, while compact
binaries of WDs are important sources of GWs at lower frequencies to be covered
by space interferometers (LISA). Major uncertainties in the current
understanding of properties of NSs and BHs most relevant to the GW studies are
discussed, including the treatment of the natal kicks which compact stellar
remnants acquire during the core collapse of massive stars and the common
envelope phase of binary evolution. We discuss the coalescence rates of binary
NSs and BHs and prospects for their detections, the formation and evolution of
binary WDs and their observational manifestations. Special attention is given
to AM CVn-stars -- compact binaries in which the Roche lobe is filled by
another WD or a low-mass partially degenerate helium-star, as these stars are
thought to be the best LISA verification binary GW sources.Comment: 105 pages, 18 figure