1,257 research outputs found
The CIFF Proof Procedure for Abductive Logic Programming with Constraints: Theory, Implementation and Experiments
We present the CIFF proof procedure for abductive logic programming with
constraints, and we prove its correctness. CIFF is an extension of the IFF
proof procedure for abductive logic programming, relaxing the original
restrictions over variable quantification (allowedness conditions) and
incorporating a constraint solver to deal with numerical constraints as in
constraint logic programming. Finally, we describe the CIFF system, comparing
it with state of the art abductive systems and answer set solvers and showing
how to use it to program some applications. (To appear in Theory and Practice
of Logic Programming - TPLP)
Influence of Extreme Weather and Climate Change on the Resilience of Power Systems: Impacts and Possible Mitigation Strategies
Integrated electrical and gas transmission network flexibility assessment in low-carbon multi-energy systems
Knowledge Representation with Multiple Logical Theories and Time
We present a knowledge representation framework where a collection of logic programs can be combined together by means of meta-level program composition operations. Each object-level program is composed of a collection of extended clauses, equipped with a time interval representing the time period in which they hold. The interaction between program composition operations and time yields a powerful knowledge representation language in which many applications can be naturally developed. The language is given a meta-level semantics which also provides an executable specification. Moreover, we define an abstract semantics by extending the immediate consequence operator from a single logic program to compositions of logic programs and taking into account time intervals. The operational, meta-level semantics is proven sound and complete with respect to the abstract bottom-up semantics. The approach is further extended in order to cope with the problem of reasoning over joined intervals of time. Three applications in the field of business regulations are shown
Deliverables 1.3 and 1.4 "Creation of non-validated computer-based models of monitored and generic LV networks ready to be used for planning studies"
Flexibility From Distributed Multienergy Systems
Multienergy systems (MES), in which multiple energy vectors are integrated and optimally operated, are key assets in low-carbon energy systems. Multienergy interactions of distributed energy resources via different energy networks generate the so-called distributed MES (DMES). While it is now well recognized that DMES can provide power system flexibility by shifting across different energy vectors, it is essential to have a systematic discussion on the main features of such flexibility. This article presents a comprehensive overview of DMES modeling and characterization of flexibility applications. The concept of ``multienergy node'' is introduced to extend the power node model, used for electrical flexibility, in the multienergy case. A general definition of DMES flexibility is given, and a general mathematical and graphical modeling framework, based on multidimensional maps, is formulated to describe the operational characteristics of individual MES and aggregate DMES, including the role of multienergy networks in enabling or constraining flexibility. Several tutorial examples are finally presented with illustrative case studies on current and future DMES practical applications
Modelling of integrated multi-energy systems : drivers, requirements, and opportunities
There is growing recognition that decarbonisation of existing uses of electricity is only ‘part of the story’ and that closer attention needs to be given to demand for energy in heating or cooling and in transport, and to all the energy vectors and infrastructures that supply the end-use demand. In this respect, concepts such as ‘multi-energy systems’ (MES) have been put forward and are gaining increasing momentum, with the aim of identifying how multiple energy systems that have been traditionally operated, planned and regulated in independent silos can be integrated to improve their collective technical, economic, and environmental performance. This paper addresses the need for modelling of MES which is capable of assessing interactions between different sectors and the energy vectors they are concerned with, so as to bring out the benefits and potential unforeseen or undesired drawbacks arising from energy systems integration. Drivers for MES modelling and the needs of different users of models are discussed, along with some of the practicalities of such modelling, including the choices to be made in respect of spatial and temporal dimensions, what these models might be used to quantify, and how they may be framed mathematically. Examples of existing MES models and tools and their capabilities, as well as of studies in which such models have been used in the authors’ own research, are provided to illustrate the general concepts discussed. Finally, challenges, opportunities and recommendations are summarised for the engagement of modellers in developing a new range of analytical capabilities that are needed to deal with the complexity of ME
Searching for Primordial Black Holes with the Einstein Telescope: impact of design and systematics
Primordial Black Holes (PBHs) have recently attracted much attention as they
may explain some of the LIGO/Virgo/KAGRA observations and significantly
contribute to the dark matter in our universe. The next generation of
Gravitational Wave (GW) detectors will have the unique opportunity to set
stringent bounds on this putative population of objects. Focusing on the
Einstein Telescope (ET), in this paper we analyse in detail the impact of
systematics and different detector designs on our future capability of
observing key quantities that would allow us to discover and/or constrain a
population of PBH mergers. We also perform a population analysis, with a mass
and redshift distribution compatible with the current observational bounds. Our
results indicate that ET alone can reach an exquisite level of accuracy on the
key observables considered, as well as detect up to tens of thousands of PBH
binaries per year, but for some key signatures (in particular high--redshift
sources) the cryogenic instrument optimised for low frequencies turns out to be
crucial, both for the number of observations and the error on the parameters
reconstruction. As far as the detector geometry is concerned, we find that a
network consisting of two separated L--shaped interferometers of 15 (20)~km arm
length, oriented at with respect to each other performs better
than a single triangular shaped instrument of 10 (15)~km arm length, for all
the metrics considered.Comment: 24 pages, 13 figure
Effects of nuclear re-interactions in quasi-elastic neutrino-nucleus scattering
The effects of nuclear re-interactions in the quasi-elastic neutrino-nucleus
scattering are investigated with a phenomenological model. We found that the
nuclear responses are lowered and their maxima are shifted towards higher
excitation energies. This is reflected on the total neutrino-nucleus cross
section in a general reduction of about 15% for neutrino energies above 300
MeV.Comment: 15 pages, 5 figures. Submitted to AstroParticle Physic
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