• Title/Summary/Keyword: Ricci operators

Search Result 12, Processing Time 0.02 seconds

Implementation Options and Economics of Phased UMTS Deployment

  • Grillo, Davide;Montagna, Maurizio;Alfano, Franco;Colombo, Antonio;Ricci, Simone
    • Journal of Communications and Networks
    • /
    • v.4 no.4
    • /
    • pp.282-291
    • /
    • 2002
  • 3GPP (Third Generation Partnership Project) is defining UMTS (Universal Mobile Telecommunication System) releases which span the transition from GSM/UMTS coexistence to All-IP UMTS networks. The deployment of an UMTS network depends, in the first place, on the intended service offerings and the release an operator chooses to start service with. Other key decisions in-fluencing UMTS deployment relate to the timing of the functional enhancements and capacity increases along the economic life of the network. This paper gives an overview on the architectural and technical options for UMTS deployment. It also outlines the methodology underlying the business plan aimed at estimating the returns from investments in the UMTS infrastructure, thus helping to tune operators’ strategies for UMTS deployment.

Jacobi Operators with Respect to the Reeb Vector Fields on Real Hypersurfaces in a Nonflat Complex Space Form

  • Ki, U-Hang;Kim, Soo Jin;Kurihara, Hiroyuki
    • Kyungpook Mathematical Journal
    • /
    • v.56 no.2
    • /
    • pp.541-575
    • /
    • 2016
  • Let M be a real hypersurface of a complex space form with almost contact metric structure (${\phi}$, ${\xi}$, ${\eta}$, g). In this paper, we prove that if the structure Jacobi operator $R_{\xi}= R({\cdot},{\xi}){\xi}$ is ${\phi}{\nabla}_{\xi}{\xi}$-parallel and $R_{\xi}$ commute with the structure tensor ${\phi}$, then M is a homogeneous real hypersurface of Type A provided that $TrR_{\xi}$ is constant.