Using pivots to explore heterogeneous collections: A case study in musicology

In order to provide a better e-research environment for musicologists, the musicSpace project has partnered with musicology’s leading data publishers, aggregated and enriched their data, and developed a richly featured exploratory search interface to access the combined dataset. There have been several significant challenges to developing this service, and intensive collaboration between musicologists (the domain experts) and computer scientists (who developed the enabling technologies) was required. One challenge was the actual aggregation of the data itself, as this was supplied adhering to a wide variety of different schemas and vocabularies. Although the domain experts expended much time and effort in analysing commonalities in the data, as data sources of increasing complexity were added earlier decisions regarding the design of the aggregated schema, particularly decisions made with reference to simpler data sources, were often revisited to take account of unanticipated metadata types. Additionally, in many domains a single source may be considered to be definitive for certain types of information. In musicology, this is essentially the case with the “works lists” of composers’ musical compositions given in Grove Music Online (http://www.oxfordmusiconline.com/public/book/omo_gmo), and so for musicSpace, we have mapped all sources to the works lists from Grove for the purposes of exploration, specifically to exploit the accuracy of its metadata in respect to dates of publication, catalogue numbers, and so on. Therefore, rather than mapping all fields from Grove to a central model, it would be far quicker (in terms of development time) to create a system to “pull-in” data from other sources that are mapped directly to the Grove works lists

musicSpace: integrating musicology's heterogeneous data sources

A significant barrier to the research endeavours of musicologists (and humanities scholars more generally) is the sheer amount of potentially relevant information that has accumulated over centuries. Whereas researchers once faced the daunting prospect of physically scouring through endless primary and secondary sources in order to answer the basic whats, wheres and whens of history, these sources and the data they contain are now increasingly available online. Yet the vast increase in the online availability of data, the heterogeneity of this data, the plethora of data providers, and, moreover, the inability of current search tools to manipulate metadata in useful and intelligent ways, means that extracting large tranches of basic factual information or running multi-part search queries is still enormously and needlessly time consuming. Accordingly, the musicSpace project is exploiting Semantic Web technologies (Berners-Lee et al., 2001) to develop a search interface that integrates access to musicology’s largest and most significant online resources. This will make previously intractable search queries tractable, thus allowing our users to spend their research time more efficiently and ultimately aiding the attainment of new knowledge. This brief paper gives an overview of our work

Discovery and exploration using musicSpace

Musicologists have to rely upon an extraordinarily heterogeneous body of primary and secondary research sources, even when conducting the most basic exploratory research. Although increasingly available online, data is nevertheless routinely catalogued or stored in numerous discrete databases according to media type (text, image, video, audio) and historical period (contemporary literature/sources, historical literature/sources), yet most musicological research cuts across these artificial divisions; researching Monteverdi’s madrigals, for example, could involve performing essentially the same search several times, because there are several relevant data sources (RISM, Grove, Naxos, RILM, BL Integrated Catalogue and BL Sound Archive). The musicSpace project seeks to integrate access to musicological data sources by providing a single search interface, thereby removing the need for search repetition and reducing inefficiency. The vast increase in on-hand data that comes with database integration both demands and allows for the development of far more sophisticated, intelligent and interactive user interfaces. Accordingly, musicSpace facilitates searching and encourages browsing by displaying search results and parameters using multiple panes, allowing instantaneous paradigmatic shifts in search focus, and employing a detailed subject ontology to enable the semi-automatic construction of complex searches. In this paper we present the musicSpace explorer interface and demonstrate its efficacy. We describe key technologies behind musicSpace to reflect on performance and scalability. In particular, however, we describe how we will be evaluating the system in use for research, and describe our longitudinal study to assess the impact of this integrated approach on artefact discovery and research query support

Quantum Entanglement and fixed point Hopf bifurcation

We present the qualitative differences in the phase transitions of the mono-mode Dicke model in its integrable and chaotic versions. We show that a first order phase transition occurs in the integrable case whereas a second order in the chaotic one. This difference is also reflected in the classical limit: for the integrable case the stable fixed point in phase space suffers a bifurcation of Hopf type whereas for the second one a pitchfork type bifurcation has been reported

Tachyonic Inflation in a Warped String Background

We analyze observational constraints on the parameter space of tachyonic inflation with a Gaussian potential and discuss some predictions of this scenario. As was shown by Kofman and Linde, it is extremely problematic to achieve the required range of parameters in conventional string compactifications. We investigate if the situation can be improved in more general compactifications with a warped metric and varying dilaton. The simplest examples are the warped throat geometries that arise in the vicinity of of a large number of space-filling D-branes. We find that the parameter range for inflation can be accommodated in the background of D6-branes wrapping a three-cycle in type IIA. We comment on the requirements that have to be met in order to realize this scenario in an explicit string compactification.Comment: Latex, JHEP class, 20 pages, 4 figures. v2: references added, small error in section 7 corrected, published versio

Inflationary Attractor from Tachyonic Matter

We study the complete evolution of a flat and homogeneous universe dominated by tachyonic matter. We demonstrate the attractor behaviour of the tachyonic inflation using the Hamilton-Jacobi formalism. We else obtain analytical approximations to the trajectories of the tachyon field in different regions. The numerical calculation shows that an initial non-vanishing momentum does not prevent the onset of inflation. The slow-rolling solution is an attractor.Comment: 4 pages, 2 figures, RevTe

Reversible Band Gap Engineering in Carbon Nanotubes by Radial Deformation

We present a systematic analysis of the effect of radial deformation on the atomic and electronic structure of zigzag and armchair single wall carbon nanotubes using the first principle plane wave method. The nanotubes were deformed by applying a radial strain, which distorts the circular cross section to an elliptical one. The atomic structure of the nanotubes under this strain are fully optimized, and the electronic structure is calculated self-consistently to determine the response of individual bands to the radial deformation. The band gap of the insulating tube is closed and eventually an insulator-metal transition sets in by the radial strain which is in the elastic range. Using this property a multiple quantum well structure with tunable and reversible electronic structure is formed on an individual nanotube and its band-lineup is determined from first-principles. The elastic energy due to the radial deformation and elastic constants are calculated and compared with classical theories.Comment: To be appear in Phys. Rev. B, Apr 15, 200

D-brane anti-D-brane effective action and brane interaction in open string channel

We construct the effective action of a $D_p$-brane-anti-$D_p$-brane system by making use of the non-abelian extension of tachyonic DBI action. We succeed the construction by restricting the Chan-Paton factors of two non-BPS $D_p$-branes in the action to the Chan-Paton factors of a $D_p\bar{D}_p$ system. For the special case that both branes are coincident, the action reduces to the one proposed by A. Sen. \\The effective $D_p\bar{D}_p$ potential indicates that when branes separation is larger than the string length scale, there are two minima in the tachyon direction. As branes move toward each other under the gravitational force, the tachyon tunneling from false to true vacuum may make a bubble formation followed by a classical evolution of the bubble. On the other hand, when branes separation is smaller than the string length scale, the potential shows one maximum and one minimum. In this case, a homogeneous tachyon rolling in real time makes an attractive potential for the branes distance. This classical force is speculated to be the effective force between the two branes.Comment: Latex, 14 pages, 1 figure, the version appears in JHE

Off-shell extension of S-matrix elements and tachyonic effective actions

We show that the on-shell S-matrix elements of four open string massless scalars, two scalars and two tachyons, and four open string tachyons in the super string theory can be written in a unique form. We then propose an off-shell extension for the S-matrix element of four scalars which is consistent, in the low energy limit, with the Dirac-Born-Infeld effective action. Using a similar off-shell extension for the S-matrix element of two scalars and two tachyons and for the S-matrix element of four tachyons, we show that they are fully consistent with the tachyonic DBI action.Comment: Latex, 17 pages, v3:a paragraph comparing off-shell and on- shell amplitudes added, reference adde