Reinjection Mechanism Research Articles

Relativistic electrons in photon fields: effects of triplet pair production on inverse Compton gamma-ray spectra

Pair production of a photon in the Coulomb field of an electron (often referred to as triplet pair production) despite the fact that it is a third-order QED process has a cross-section that exceeds the Compton cross-section for energies of collision ≥ 250 m e c 2 . The problem of ultrarelativistic electrons entering a photon field is re-examined by including triplet pair production as both an energy loss and re-injection mechanism for electrons. The steady state electron distribution and photon spectrum for monoenergetic and power-law electron injections are calculated and compared with the results obtains in the pure Compton case, i.e. by ignoring triplet pair production

Facenet: A connectionist model of face identification in context

Abstract The role of contexts in face identification constitutes a weak point of existing cognitive models of face recognition. A connectionist system (Face-net) based on a layered network has been specified and implemented to investigate the processes underlying identification. The architecture of the Face net system takes contextual information explicitly into account in the construction of identity representations, and is provided with a reinjection mechanism which gives it dynamic properties. The model proposes that three indicators are extracted in parallel in person identification from a face: familiarity feeling (feeling of deja-vu of the face stimulus), identity feeling (feeling that we know the person) and identity content (information about the person resulting from the integration of the contexts). Face net underwent an experimental procedure to study the structuring of identity representations in various learning conditions defined by the specificity and the variability of the encoding context...

Cliff: Sudden enhancement or enfeeblement of chaos in dissipative dynamical systems

We investigate cliff, which is a phenomenon such that the Lyapunov exponent ( L) has an infinite slope in the chaotic region as a parameter ( r) is varied. We show in the framework of 2-dimensional maps with a suitable reinjection mechanism that it is caused by pair annihilation of an unstable focus and a saddle at r = r′ c as follows: L(r)−L(r′' c)∝|r−r′ c| 3 4 while it does not happen in the case of unstable node-saddle collapse.