46,083 research outputs found
Odd-primary homotopy exponents of compact simple Lie groups
We note that a recent result of the second author yields upper bounds for
odd-primary homotopy exponents of compact simple Lie groups which are often
quite close to the lower bounds obtained from v_1-periodic homotopy theory.Comment: This is the version published by Geometry & Topology Monographs on 22
February 200
Practical applications of data mining in plant monitoring and diagnostics
Using available expert knowledge in conjunction with a structured process of data mining, characteristics observed in captured condition monitoring data, representing characteristics of plant operation may be understood, explained and quantified. Knowledge and understanding of satisfactory and unsatisfactory plant condition can be gained and made explicit from the analysis of data observations and subsequently used to form the basis of condition assessment and diagnostic rules/models implemented in decision support systems supporting plant maintenance. This paper proposes a data mining method for the analysis of condition monitoring data, and demonstrates this method in its discovery of useful knowledge from trip coil data captured from a population of in-service distribution circuit breakers and empirical UHF data captured from laboratory experiments simulating partial discharge defects typically found in HV transformers. This discovered knowledge then forms the basis of two separate decision support systems for the condition assessment/defect clasification of these respective plant items
Pressure Dependence of Energetic (160 keV) Focused Electron Beams Arising From Heated or Cooled (LiNbO3) Pyroelectric Crystals
A new effect, gas amplification of electron energy is reported here; namely
when a cylindrical pyroelectric crystal such as (LiNbO3) is contained in a
concentric cylindrical chamber and is heated and then allowed to cool in a
dilute gas the maximum energy of the resultant focused electron beam more than
doubles as the pressure increases from 0.05 to 4 mTorr for seven different
gases.Comment: 5 pages, 5 figures, pd
Exploiting multi-agent system technology within an autonomous regional active network management system
This paper describes the proposed application of multi-agent system (MAS) technology within AuRA-NMS, an autonomous regional network management system currently being developed in the UK through a partnership between several UK universities, distribution network operators (DNO) and a major equipment manufacturer. The paper begins by describing the challenges facing utilities and why those challenges have led the utilities, a major manufacturer and the UK government to invest in the development of a flexible and extensible active network management system. The requirements the utilities have for a network automation system they wish to deploy on their distribution networks are discussed in detail. With those requirements in mind the rationale behind the use of multi-agent systems (MAS) within AuRA-NMS is presented and the inherent research and design challenges highlighted including: the issues associated with robustness of distributed MAS platforms; the arbitration of different control functions; and the relationship between the ontological requirements of Foundation for Intelligent Physical Agent (FIPA) compliant multi-agent systems, legacy protocols and standards such as IEC 61850 and the common information model (CIM)
Securing a Quantum Key Distribution Network Using Secret Sharing
We present a simple new technique to secure quantum key distribution relay
networks using secret sharing. Previous techniques have relied on creating
distinct physical paths in order to create the shares. We show, however, how
this can be achieved on a single physical path by creating distinct logical
channels. The technique utilizes a random 'drop-out' scheme to ensure that an
attacker must compromise all of the relays on the channel in order to access
the key
Extending the Reach of QKD Using Relays
One of the obstacles to deployment of QKD solutions has been the distance
limitation. Solutions using relays have been proposed but these rely on
link-by-link key establishment. We present a new technique to extend the
distance of a quantum key distribution channel using an active relay. Each
relay acts as an intercept/resend device and allows the establishment of an
end-to-end key. It has been argued that such relays cannot be used to extend
the distance, but we show that with a suitable adaptation of the protocol the
effective key distribution distance can be increased
- …