Dublin City University

About: Dublin City University is a education organization based out in Dublin, Ireland. It is known for research contribution in the topics: Context (language use) & Machine translation. The organization has 5904 authors who have published 17178 publications receiving 389376 citations. The organization is also known as: National Institute for Higher Education, Dublin & DCU.

A multiswitchable poly(terthiophene) bearing a spiropyran functionality: understanding photo- and electrochemical control.

Abstract: An electroactive nitrospiropyran-substituted polyterthiophene, poly(2-(3,3′′-dimethylindoline-6′-nitrobenzospiropyranyl)ethyl 4,4′′-didecyloxy-2,2′:5′,2′′-terthiophene-3′-acetate), has been synthesized for the first time. The spiropyran, incorporated into the polymer backbone by covalent attachment to the alkoxyterthiophene monomer units, leads to multiple colored states as a result of both photochemical and electrochemical isomerization of the spiropyran moiety to merocyanine forms as well as electrochemical oxidation of the polyterthiophene backbone and the merocyanine substituents. While electrochemical polymerization of the terthiophene monomer can take place without oxidation of the spiropyran, increasing the oxidation potential leads to complex electrochemistry that clearly involves this substituent. To understand this complex behavior, the first detailed electrochemical study of the oxidation of the precursor spiropyran, 1-(2-hydroxyethyl)-3,3-dimethylindoline-6′-nitrobenzospiropyran, was undertake...

Sol-gel immobilised ruthenium(II) polypyridyl complexes as chemical transducers for optical pH sensing

Abstract: A range of fluorescent ruthenium(II) polypyridyl complexes have been employed in an optical sensor device for pH analysis. The dye materials were immobilised in a sol–gel glass matrix and characterised upon exposure to aqueous buffer solutions. Changes of below 0.1 pH units were detectable using these dye-doped glass films, and linear ranges as large as pH 3–9 were observed. Sol–gel immobilisation effectively enhanced the operating range of these materials compared to solution. Interference from fluorescence quenching due to molecular oxygen was found to place important restrictions on the nature of dyes suitable for this application.

Bank credit and trade credit: Evidence from SMEs over the financial crisis

Abstract: This article uses panel data to test the extent to which trade credit acted as a substitute for bank finance in Small and Medium-sized Enterprises (SMEs), in the aftermath of the financial crisis of 2008. It demonstrates that the reduction in the supply of funds to SMEs was compounded by the contraction of net trade credit within the sector. Nevertheless, trade credit played a vital role in the adjustment of the sector by easing the burden of the financial crisis for some SMEs. Thus, the relative importance of trade credit increased for financially “vulnerable” SMEs that were less liquid, highly dependent on short-term bank finance, and with greater levels of intangible assets, when entering the crisis. In terms of a redistribution effect, financially stronger firms extended relatively more trade credit, to financially vulnerable SMEs in the aftermath of the financial crisis. In addition, the analysis demonstrates that the financial position of SMEs entering the crisis was more important in determining th...

Exponential bounds for queues with Markovian arrivals

Abstract: Exponential bounds P(queue > b) < ~e -'rb are found for queues whose increments are described by Markov Additive Processes. This is done by application of maximal inequalities to exponential martingales for such processes. Through a thermodynamic approach the constant ,~ is shown to be the decay rate for an asymptotic lower bound for the queue length distribution. The class of arrival processes considered includes a wide variety of Markovian multiplexer models, and a general treatment of these is given, along with that of Markov modulated arrivals. Particular attention is paid to the calculation of the prefactor ~y. The problem of finding the queue length distribution in a queue with non- independent arrivals has attracted much attention recently due to applications in the design of multiplexers for the emergent asynchronous transfer mode (ATM) of data transmission in integrated services digital networks (ISDN). From the tech- nological point of view it is required to guarantee sufficiently good quality of service: loss probabilities must be appropriately small and waiting times sufficiently short. The problem is resistant to simple exact treatment due to the nature of the arrival process. It is a superposition of sources which are typically bursty, in the sense that their activity is highly correlated into bursts rather than occurring indepen- dently at different times; and periodic (when viewed at the short time scales of the multiplexer output) either due to their origin (e.g. periodic sampling of voice traf- fic) or their occupation of periodic slots allocated for transmission. The goal of ana- lysis is to provide mechanisms for design and performance prediction, and algorithms for allocation of resources during the operation of such devices. It is desirable that the results of such analysis be conservative in the sense that they should not overestimate the capacity of resources.