Centrality and vulnerability in liner shipping networks: Revisiting the Northeast Asian port hierarchy

International audienceThis paper is essentially an empirical investigation in the network analysis of inter-port traffic flows. Based on a database of vessel movements, it applies conventional techniques of network analysis to the graph of Northeast Asian liner networks in 1996 and 2006. Such approach proves particularly helpful for analysing the changing position of major hub ports and for revealing their respective tributary areas within the region. Despite rapid traffic growth at Chinese ports during the period under study, the latter seem to remain polarized by established hubs such as Korean ports and Hong Kong. This research reveals the strong relation between local port policies and the evolution of shipping network desig

Port competition and network polarization at the East Asian maritime corridor

National audiencePort competition is often analyzed based on individual characteristics of seaports rather than inter-port connections. A maritime network perspective is applied to the circulation of liner vessels between East Asian ports in order to reveal their relative position in 1996 and 2006. Main results confirm the progress of secondary ports over their major competitors, reflecting the importance of local port policies. However, the overall structure of the regional network tends to remain polarized by few major hub ports resisting to internal and external threatsL'analyse de la concurrence portuaire se base souvent sur les caractéristiques individuelles des ports plutôt que sur les connections interportuaires. L'analyse réseau de la circulation des porte-conteneurs entre les ports d'Asie orientale permet de révéler leur position relative en 1996 et 2006. Les résultats confirment la montée de ports secondaires face à leurs concurrents principaux, reflétant par là l'importance des politiques portuaires locales. Cependant, la structure d'ensemble du réseau régional reste polarisée par quelques hubs majeurs parvenant à surmonter leurs difficultés internes et externe

On Hawking's Local Rigidity Theorems for Charged Black Holes

We show the existence of a Hawking vector field in a full neighborhood of a local, regular, bifurcate, non-expanding horizon embedded in a smooth Einstein-Maxwell space-time without assuming the underlying space-time is analytic. It extends one result of Friedrich, R\'{a}cz and Wald, which was limited to the interior of the black hole region. Moreover, we also show, in the presence of an additional Killing vector field $T$ which tangent to the horizon and not vanishing on the bifurcate sphere, then space-time must be locally axially symmetric without the analyticity assumption. This axial symmetry plays a fundamental role in the classification theory of stationary black holes.Comment: 20 page

An interpretation for the entropy of a black hole

We investigate the meaning of the entropy carried away by Hawking radiations from a black hole. We propose that the entropy for a black hole measures the uncertainty of the information about the black hole forming matter's precollapsed configurations, self-collapsed configurations, and inter-collapsed configurations. We find that gravitational wave or gravitational radiation alone cannot carry all information about the processes of black hole coalescence and collapse, while the total information locked in the hole could be carried away completely by Hawking radiation as tunneling

Reflection, radiation and interference for black holes

Black holes are capable of reflection: there is a finite probability for any particle that approaches the event horizon to bounce back. The albedo of the black hole depends on its temperature and the energy of the incoming particle. The reflection shares its physical origins with the Hawking process of radiation, both of them arise as consequences of the mixing of the incoming and outgoing waves that takes place on the event horizon.Comment: 10 pages, 1 figure, Revte

Comment about UV regularization of basic commutators in string theories

Recently proposed by Hwang, Marnelius and Saltsidis zeta regularization of basic commutators in string theories is generalized to the string models with non-trivial vacuums. It is shown that implementation of this regularization implies the cancellation of dangerous terms in the commutators between Virasoro generators, which break Jacobi identity.Comment: LaTeX, 9 pages, no figures, submitted to Physics Letters

Thermodynamics Inducing Massive Particles' Tunneling and Cosmic Censorship

By calculating the change of entropy, we prove that the first law of black hole thermodynamics leads to the tunneling probability of massive particles through the horizon, including the tunneling probability of massive charged particles from the Reissner-Nordstr\"om black hole and the Kerr-Newman black hole. Novelly, we find the trajectories of massive particles are close to that of massless particles near the horizon, although the trajectories of massive charged particles may be affected by electromagnetic forces. We show that Hawking radiation as massive particles tunneling does not lead to violation of the weak cosmic-censorship conjecture

Scattering of scalar particles by a black hole

The absorption cross section for scalar particle impact on a Schwarzschild black hole is found. The process is dominated by two physical phenomena. One of them is the well-known greybody factor that arises from the energy-dependent potential barrier outside the horizon that filters the incoming and outgoing waves. The other is related to the reflection of particles on the horizon (Kuchiev 2003). This latter effect strongly diminishes the cross section for low energies, forcing it to vanish in the infrared limit. It is argued that this is a general property, the absorption cross section vanishes in the infrared limit for scattering of particles of arbitrary spin.Comment: 7 pages, revtex, 1 figur