Diana Costa

Bio: Diana Costa is an academic researcher from University College London. The author has contributed to research in topics: Hybrid logic & Computer science. The author has an hindex of 3, co-authored 8 publications receiving 26 citations. Previous affiliations of Diana Costa include University of Aveiro.

Paraconsistency in hybrid logic

Abstract: As in standard knowledge bases, hybrid knowledge bases (i.e., sets of information specified by hybrid formulas) may contain inconsistencies arising from different sources, namely from the many mechanisms used to collect relevant information. Being a fact, rather than a queer anomaly, inconsistency also needs to be addressed in the context of hybrid logic applications. This paper introduces a paraconsistent version of hybrid logic which is able to accommodate inconsistencies at local points without implying global failure. A main feature of the resulting logic, crucial to our approach, is the fact that every hybrid formula has an equivalent formula in negation normal form. The paper also provides a measure to quantify the inconsistency of a hybrid knowledge base, useful as a possible basis for comparing knowledge bases. Finally, the concepts of extrinsic and intrinsic inconsistency of a theory are discussed.

Reasoning over Permissions Regions in Concurrent Separation Logic

Abstract: We propose an extension of separation logic with fractional permissions, aimed at reasoning about concurrent programs that share arbitrary regions or data structures in memory. In existing formalisms, such reasoning typically either fails or is subject to stringent side conditions on formulas (notably precision) that significantly impair automation. We suggest two formal syntactic additions that collectively remove the need for such side conditions: first, the use of both “weak” and “strong” forms of separating conjunction, and second, the use of nominal labels from hybrid logic. We contend that our suggested alterations bring formal reasoning with fractional permissions in separation logic considerably closer to common pen-and-paper intuition, while imposing only a modest bureaucratic overhead.

Inconsistencies in health care knowledge

Abstract: In this paper we focus in health care knowledge, specified by hybrid formulas, representing flows of medical assistance in the care delivery process in a hospital. As in standard knowledgebases inconsistencies may arise. In fact, Medical Informatics is one field where the ability to reason with inconsistent information is crucial. Patients can receive different, and moreover contradictory, diagnoses from different physicians, and the same can happen with medical treatments: they can exhibit contradictory symptoms. We introduce a paraconsistent version of multimodal hybrid logic to help with this medical issue, specially through the diagnosis.

Effects of PCB-77 in adult zebrafish after exposure during early life stages

Abstract: Polychlorinated biphenyls (PCBs) are a class of industrial chemicals that cause endocrine changes, since they are able to bind to estrogen receptors and interfere with estrogen-regulated pr...

A Tableau System for Quasi-Hybrid Logic

Abstract: Hybrid logic is a valuable tool for specifying relational structures, at the same time that allows defining accessibility relations between states, it provides a way to nominate and make mention to what happens at each specific state. However, due to the many sources nowadays available, we may need to deal with contradictory information. This is the reason why we came with the idea of Quasi-hybrid logic, which is a paraconsistent version of hybrid logic capable of dealing with inconsistencies in the information, written as hybrid formulas. In [5] we have already developed a semantics for this paraconsistent logic. In this paper we go a step forward, namely we study its proof-theoretical aspects. We present a complete tableau system for Quasi-hybrid logic, by combining both tableaux for Quasi-classical and Hybrid logics.

Measuring consistency gain and information loss in stepwise inconsistency resolution

Abstract: Inconsistency is a usually undesirable feature of many kinds of data and knowledge. But altering the information in order to make it less inconsistent may result in the loss of information. In this paper we analyze this trade-off. We review some existing proposals and make new proposals for measures of inconsistency and information. We prove that in both cases the various measures are all pairwise incompatible. Then we introduce the concept of stepwise inconsistency resolution and show what happens in case an inconsistency resolution step applies a deletion, a weakening, or a splitting operation. © 2011 Springer-Verlag Berlin Heidelberg.

Phenotypic Switching Resulting From Developmental Plasticity: Fixed or Reversible?

Abstract: The prevalent view of developmental phenotypic switching holds that phenotype modifications occurring during critical windows of development are "irreversible" - that is, once produced by environmental perturbation, the consequent juvenile and/or adult phenotypes are indelibly modified. Certainly, many such changes appear to be non-reversible later in life. Yet, whether animals with switched phenotypes during early development are unable to return to a normal range of adult phenotypes, or whether they do not experience the specific environmental conditions necessary for them to switch back to the normal range of adult phenotypes, remains an open question. Moreover, developmental critical windows are typically brief, early periods punctuating a much longer period of overall development. This leaves open additional developmental time for reversal (correction) of a switched phenotype resulting from an adverse environment early in development. Such reversal could occur from right after the critical window "closes," all the way into adulthood. In fact, examples abound of the capacity to return to normal adult phenotypes following phenotypic changes enabled by earlier developmental plasticity. Such examples include cold tolerance in the fruit fly, developmental switching of mouth formation in a nematode, organization of the spinal cord of larval zebrafish, camouflage pigmentation formation in larval newts, respiratory chemosensitivity in frogs, temperature-metabolism relations in turtles, development of vascular smooth muscle and kidney tissue in mammals, hatching/birth weight in numerous vertebrates,. More extreme cases of actual reversal (not just correction) occur in invertebrates (e.g., hydrozoans, barnacles) that actually 'backtrack' along normal developmental trajectories from adults back to earlier developmental stages. While developmental phenotypic switching is often viewed as a permanent deviation from the normal range of developmental plans, the concept of developmental phenotypic switching should be expanded to include sufficient plasticity allowing subsequent correction resulting in the normal adult phenotype.

Four-valued modal logic: Kripke semantics and duality.

Abstract: Combining multi-valued and modal logics into a single system is a long-standing concern in mathematical logic and computer science, see for example [7] and the literature cited there. Recent work in this trend [15, 17, 14] develops modal expansions of many-valued systems that are also inconsistencytolerant, along the tradition initiated by Belnap with his “useful four-valued logic” [3]. Our contribution continues on this line, and the specific problem we address is that of defining and axiomatizing the least modal logic over the four-element Belnap lattice. The problem was inspired by [5], but our solution is quite different from (and in some respects more satisfactory than) that of [5] in that we make an extensive and profitable use of algebraic and topological techniques. In fact, our algebraic and topological analyses of the logic have, in our opinion, an independent interest and contribute to the appeal of our approach. Kripke frames provide a semantics for modal logics that is both flexible with regards to intended applications and interpretations, and highly intuitive. When the non-modal part is multi-valued, though, one may wonder whether the accessibility relation between worlds should remain two-valued or be allowed to assume the same range of truth values as the logic itself. Starting from the point of view of AI applications, [7] argues forcefully that multiple values are an appropriate and useful modeling device. This is the approach taken in [5] and here, too. Our aim is to study the least modal logic over the Belnap lattice, that is, the logic determined by the class of all Kripke frames where the accessibility relation as well as semantic valuations are four-valued.

Proceedings of the 2012 international conference on Process Support and Knowledge Representation in Health Care

Abstract: This book comprises thoroughly refereed and revised papers from the BPM'12 Joint Workshop on Process-Oriented Information Systems and Knowledge Representation in Health Care (ProHealth'12 / KR4HC'12), which was held in Tallinn, Estonia, in September 2012. Healthcare organizations are facing the challenge of delivering high quality services to their patients at affordable costs. These challenges become more prominent with the growth in the aging population with chronic diseases and the rise of healthcare costs. High degree of specialization of medical disciplines, huge amounts of medical knowledge and patient data to be consulted in order to provide evidence-based recommendations, and the need for personalized healthcare are prevalent trends in this information-intensive domain. The emerging situation necessitates computer-based support of healthcare process & knowledge management as well as clinical decision-making. The ProHealth'12 / KR4HC'12 workshop brought together researchers from two communities who have been addressing these challenges from two different perspectives. The knowledge-representation for healthcare community, which is part of the larger medical informatics community, has been focusing on knowledge representation and reasoning to support knowledge management and clinical decision-making. In turn, the process-oriented information systems in healthcare community, which is part of the larger business process management (BPM) community, has been studying ways to adopt BPM technology in order to provide effective solutions for healthcare process management. Adopting BPM technology in the healthcare sector is starting to address some of the unique characteristics of healthcare processes, including their high degree of flexibility, the integration with EMRs and shared semantics of healthcare domain concepts, and the need for tight cooperation and communication among medical care teams.