136,951 research outputs found
Anti-de-Sitter-Maxwell-Yang-Mills black holes thermodynamics from nonlocal observables point of view
In this paper, we analyze the thermodynamic properties of the Anti de Sitter
black hole in the Einstein-Maxwell-Yang-Mills-AdS gravity (EMYM) via many
approaches and in different thermodynamical ensembles (canonical/ grand
canonical). First, we give a concise overview of this phase structure in the
entropy-thermal diagram for fixed charges then we investigate this
thermodynamical structure in fixed potentials ensemble. The Next relevant step
is recalling the nonlocal observables such as holographic entanglement entropy
and two-point correlation function to show that both observables exhibit a Van
der Waals-like behavior in our numerical accuracy and just near the critical
line as the case of the thermal entropy for fixed charges by checking Maxwell's
equal area law and the critical exponent. In the light of the grand canonical
ensemble, we also find a newly phase structure for such a black hole where the
critical behavior disappears in the thermal picture as well as in the
holographic one.Comment: 23 pages, 9 figures, Advances in High Energy Physics accepted versio
Resource management in IP-based radio access networks
IP is being considered to be used in the Radio Access Network (RAN) of UMTS. It is of paramount importance to be able to provide good QoS guarantees to real time services in such an IP-based RAN. QoS in IP networks is most efficiently provided with Differentiated services (Diffserv). However, currently Diffserv mainly specifies Per Hop Behaviors (PHB). Proper mechanisms for admission control and resource reservation have not yet been defined. A new resource management concept in the IP-based RAN is needed to offer QoS guarantees to real time services. We investigate the current Diffserv mechanisms and contribute to development of a new resource management protocol. We focus on the load control algorithm [9], which is an attempt to solve the problem of admission control and resource reservation in IP-based networks. In this document we present some load control issues and propose to enhance the load control protocol with the Measurement Based Admission Control (MBAC) concept. With this enhancement the traffic load in the IP-based RAN can be estimated, since the ingress router in the network path can be notified by marking packets with the resource state information. With this knowledge, the ingress router can perform admission control to keep the IP-based RAN stable with a high utilization even in overload situations
High-directivity acoustic antenna
Acoustic antenna with unique electronic steering control is used to identify and define aerodynamic noise sources in free field, particularly in wind tunnel which is quite reverberant. Provision is made for high directivity as well as improved discrimination against unwanted background noise such as reverberation or echoes
Generalized coherent and intelligent states for exact solvable quantum systems
The so-called Gazeau-Klauder and Perelomov coherent states are introduced for
an arbitrary quantum system. We give also the general framework to construct
the generalized intelligent states which minimize the Robertson-Schr\"odinger
uncertainty relation. As illustration, the P\"oschl-Teller potentials of
trigonometric type will be chosen. We show the advantage of the analytical
representations of Gazeau-Klauder and Perelomov coherent states in obtaining
the generalized intelligent states in analytical way
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