Srinandan Dasmahapatra

Identifying communities of practice through ontology network analysis

This article describes Ontocopi, a tool for identifying communities of practice by analyzing ontologies of relevant working domains. Ontocopi spots patterns in ontological formal relations, traversing the ontology from instance to instance via selected relations.

Ontology-based medical image annotation with description logics

The interpretation of medical evidence is normally presented in terms of a controlled, but diversely expressed specialist vocabulary and natural language phrases. Such informally expressed data require human intervention to ascertain its relevance in any specific case. In order to facilitate machine-based reasoning about the evidence gathered, additional interpretive semantics must be attached to the data; a shift from a merely data-intensive approach to a semantics-rich model of evidence. In this paper, we present a system to formally annotate medical images captured to aid the diagnosis and management of breast cancer, that enables a series of semantics-based operations to be performed. Our approach is grounded upon an imaging ontology specifying the domain knowledge and a description logic (DL) taxonomic inferential engine responsible for semantics-based reasoning and image retrieval.

HealthAgents: distributed multi-agent brain tumor diagnosis and prognosis

Abstract We present an agent-based distributed decision support system for the diagnosis and prognosis of brain tumors developed by the HealthAgents project. HealthAgents is a European Union funded research project, which aims to enhance the classification of brain tumors using such a decision support system based on intelligent agents to securely connect a network of clinical centers. The HealthAgents system is implementing novel pattern recognition discrimination methods, in order to analyze in vivo Magnetic Resonance Spectroscopy (MRS) and ex vivo/in vitro High Resolution Magic Angle Spinning Nuclear Magnetic Resonance (HR-MAS) and DNA micro-array data. HealthAgents intends not only to apply forefront agent technology to the biomedical field, but also develop the HealthAgents network, a globally distributed information and knowledge repository for brain tumor diagnosis and prognosis.

Managing Reference: Ensuring Referential Integrity of Ontologies for the Semantic Web

The diversity and distributed nature of the resources available in the semantic web poses significant challenges when these are used to help automatically build an ontology. One persistent and pervasive problem is that of the resolution or elimination of coreference that arises when more than one identifier is used to refer to the same resource. Tackling this problem is crucial for the referential integrity, and subsequently the quality of results, of any ontology-based knowledge service. We have built a coreference management service to be used alongside the population and maintenance of an ontology. An ontology based knowledge service that identifies communities of practice (CoPs) is also used to maintain the heuristics used in the coreference management system. This approach is currently being applied in a large scale experiment harvesting resources from various UK computer science departments with the aim of building a large, generic web-accessible ontology.

Quasi-Particles, Conformal Field Theory, and q-Series

We review recent results concerning the representation of conformal field theory characters in terms of fermionic quasi-particle excitations, and describe in detail their construction in the case of the integrable three-state Potts chain. These fermionic representations are q-series which are generalizations of the sums occurring in the Rogers-Ramanujan identities.

N-species stochastic models with boundaries and quadratic algebras

Stationary probability distributions for stochastic processes on linear chains with closed or open ends are obtained using the matrix product ansatz. The matrices are representations of some quadratic algebras. The algebras and the types of representations considered depend on the boundary conditions. In the language of quantum chains we obtain the ground state of N-state quantum chains with free boundary conditions or with non-diagonal boundary terms at one or both ends. In contrast to problems involving the Bethe ansatz, we do not have a general framework for arbitrary N, which when specialized, gives the known results for N = 2; in fact, the N = 2 and N>2 cases appear to be very different.

Semantic metrics

In the context of the Semantic Web, many ontology-related operations, e.g., ontology ranking, segmentation, alignment, articulation, reuse, evaluation, etc., can be boiled down to one fundamental operation: computing the similarity and/or dissimilarity among ontological entities, and in some cases among ontologies. In this paper, we review conventional metrics for computing distance and we propose a series of metrics conceived purposely for semantics rich entities. We give a formal account of semantic metrics drawn from a variety of research disciplines and enrich them with formalisation based on Description Logics. We argue that concept-based metrics can be aggregated to produce numeric distances at ontology-level. We speculate on the usability of our ideas in potential ontology engineering tasks.

Virasoro characters from bethe equations for the critical ferromagnetic three-state potts model

We obtain new fermionic sum representations for the Virasoro characters of the conformal field theory describing the ferromagnetic three-state Potts spin chain. These arise from the fermionic quasiparticle excitations derived from the Bethe equations for the eigenvalues of the Hamiltonian. In the conformal scaling limit, the Bethe equations provide a description of the spectrum in terms of one genuine quasiparticle and two “ghost” excitations with a limited microscopic momentum range. This description is reflected in the structure of the character formulas, and suggests a connection with the integrable perturbation of dimensions (2/3, 2/3)+ which breaks theS3 symmetry of the conformal field theory down toZ2.

A knowledgeable security model for distributed health information systems

Realising the vision of pervasive healthcare will generate new challenges to system security. Such challenges are fundamentally different from issues and problems that we face in centralised approaches as well as non-clinical scenarios. In this paper, we reflect upon our experiences in the HealthAgents project wherein a prototype system was developed and a novel approach employed that supports data transfer and decision making in human brain tumour diagnosis and treatment. While the decision making needs to rely on different clinical expertise, the HealthAgents system leveraged a domain ontology to align different sub-domain vocabularies and we have experimented with a process calculus to glue together distributed services. We examine the capability of the Lightweight Coordination Calculus (LCC), a process calculus based language, in meeting security challenges in pervasive settings, especially in the healthcare domain. The key difference in approach lies in making the representational abstraction reflect the relative autonomy of the various clinical specialisms involved in contributing to patient management. The scope within LCC of accommodating Boolean-valued constraints allows for flexible integration of heterogeneous sources in multiple formats, which are characteristic features of a pervasive healthcare environment.

Reflections on a medical ontology

In this paper we confront the divide between the ontologies developed from the requirement of comprehensive and general domain coverage and those devised to meet application-specific requirements. While the generalists typically attach philosophical sophistication to their approach, in supposed contrast to the narrow remit chosen by the application-bound knowledge engineers, we would like to indicate that the latter practice can often reflect a multi-faceted rationale, nuanced by the requirements of the domain. We demonstrate how the necessity of placing ontology-based systems with the work-practices of domain experts introduces unique demands on design rationales and enforces, often implicitly, a philosophical assessment of the necessary concepts and relations that balance the generality and specificity. Such demands are not addressed by generic approaches to modelling the reality of a domain. Indeed, we articulate the philosophical and practical considerations that we have taken into account when developing an application-specific ontology. We would certainly hope that our experiences can be of help to the development of ontologies in similar applications.