Virtual Private Networks: Turning the Internet into Your Private Network

Scott, Charlie; Wolfe, Paul J.; Erwin, Mike

doi:10.1201/1079/43248.27.2.19990801/30263.5

Cited by 9 publications

(9 citation statements)

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“…The function f (r) can be any function which is normalized to unit value at the center of the spacetime distortion, and falls off rapidly at some finite radius, asymptotically approaching zero at large r. Alcubierre gave a particular example of such a function, 1 One might argue that the center of the warp bubble would be in the engineering area of the starship [7]; for our purposes, we shall define the center to be the 'bridge' of the starship.…”

Section: Typeset Using Revt E Xmentioning

confidence: 99%

Null geodesics in the Alcubierre warp-drive spacetime: the view from the bridge

Clark¹,

Hiscock²,

Larson³

1999

Class. Quantum Grav.

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The null geodesic equations in the Alcubierre warp drive spacetime are numerically integrated to determine the angular deflection and redshift of photons which propagate through the distortion of the "warp drive" bubble to reach an observer at the origin of the warp effect. We find that for a starship with an effective warp speed exceeding the speed of light, stars in the forward hemisphere will appear closer to the direction of motion than they would to an observer at rest. This aberration is qualitatively similar to that caused by special relativity. Behind the starship, a conical region forms from within which no signal can reach the starship, an effective "horizon". Conversely, there is also an horizon-like structure in a conical region in front of the starship, into which the starship cannot send a signal. These causal structures are somewhat analogous to the Mach cones associated with supersonic fluid flow. * e-mail: chadc@orion.physics.montana.edu † e-mail: hiscock@montana.edu ‡ e-mail: shane@orion.physics.montana.edu 1The existence of these structures suggests that the divergence of quantum vacuum energy when the starship effectively exceeds the speed of light, first discovered in two dimensions, will likely be present in four dimensions also, and prevent any warp-drive starship from ever exceeding the effective speed of light.Typeset using REVT E X 2 Alcubierre [1] has described a spacetime which has features reminiscent of the "warp drive" common in science fiction lore. The Alcubierre solution allows a "starship" to have an apparent speed relative to distant observers which is much greater than the speed of light, an effect caused by the spacetime expanding behind and contracting in front of the starship.In such a spacetime, passengers on the starship can travel arbitrarily large distances in small amounts of proper time; further, there is no time dilation effect between the starship and clocks outside the region affected by the warp drive.If a technology based on such a spacetime could be realized, space travel to distant points in our Universe could seem almost plausible. The Alcubierre warp drive spacetime has properties, however, which make it unlikely to be physical. As Alcubierre himself pointed out, in order to create the distortion of spacetime which produces the warp drive effect, "exotic" matter is required, which violates the weak, strong, and dominant energy conditions. Although quantized fields can locally violate the energy conditions, an analysis by Pfenning and Ford [2] has shown that the distribution of exotic matter needed to generate the warp 'bubble' around the starship appears quite implausible. Additional work has shown that any spacetime that permits apparent superluminal travel will inevitably violate the weak and averaged null energy conditions [3][4][5]. On the other hand, Van Den Broeck has recently shown how to significantly reduce the amount of negative energy density matter required for the warp drive to the order of grams [6].Even if one could somehow obtain the ...

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Section: Typeset Using Revt E Xmentioning

confidence: 99%

Null geodesics in the Alcubierre warp-drive spacetime: the view from the bridge

Clark¹,

Hiscock²,

Larson³

1999

Class. Quantum Grav.

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“…In the ProViT-project the problem is solved by the building up of virtual tunnels dynamically (similar to virtual private networks). 23 They wrap up all Multicast-Data-Packets into normal TCP/IP-Data-Packets for sending them over the Internet. To realize this approach following architecture was developed.…”

Section: Intentions Of the Nmsmentioning

confidence: 99%

Design Review in a Distributed Collaborative Virtual Environment

Cao

Gaertner

Guddat

et al. 2006

Int. J. Image Grap.

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Int. J. Image Grap. 2006.06:45-63. Downloaded from www.worldscientific.com by UNIVERSITY OF CALGARY on 02/06/15. For personal use only. 46 W. Cao et al.Virtual Reality leads Digital Product Development technology to a more effective and convenient way by presenting the product model in an immersive real 3D environment. Distributed VR even enables partners to discuss the design of the product independent of their locations. This paper introduces our work with a Digital Product Development System with Virtually Cooperating Teams Using High Bandwidth Networks -ProViT, which aims at building up immersive telepresence systems for design review across high-bandwidth networks. Video and audio streaming are integrated in the virtual environment to support immersive teleconference aspects of the distributed design review sessions. A network management system has been developed for the supervision, maintenance and processing of distributed setups, and network security.

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“…(5)) as follows: i ðh j Þ is computed incrementally using Eqs. (3), (4). We obtain b p i ðh j Þ as follows:…”

Section: Symptom Lossmentioning

confidence: 99%

Probabilistic fault diagnosis in communication systems through incremental hypothesis updating

Steinder

Sethi

2004

Computer Networks

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This paper presents a probabilistic event-driven fault localization technique, which uses a probabilistic symptomfault map as a fault propagation model. The technique isolates the most probable set of faults through incremental updating of a symptom-explanation hypothesis. At any time, it provides a set of alternative hypotheses, each of which is a complete explanation of the set of symptoms observed thus far. The hypotheses are ranked according to a measure of their goodness. The technique allows multiple simultaneous independent faults to be identified and incorporates both negative and positive symptoms in the analysis. As shown in a simulation study, the technique offers close-to-optimal accuracy and is resilient both to noise in the symptom data and to inaccuracies of the probabilistic fault propagation model.

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Virtual Private Networks: Turning the Internet into Your Private Network

Cited by 9 publications

References 0 publications

Null geodesics in the Alcubierre warp-drive spacetime: the view from the bridge

Null geodesics in the Alcubierre warp-drive spacetime: the view from the bridge

Design Review in a Distributed Collaborative Virtual Environment

Probabilistic fault diagnosis in communication systems through incremental hypothesis updating

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