Towards Informative Statistical Flow Inversion

This is the accepted version of 'Towards Informative Statistical Flow Inversion', archived originally at arXiv:0705.1939v1 [cs.NI] 14 May 2007.A problem which has recently attracted research attention is that of estimating the distribution of flow sizes in internet traffic. On high traffic links it is sometimes impossible to record every packet. Researchers have approached the problem of estimating flow lengths from sampled packet data in two separate ways. Firstly, different sampling methodologies can be tried to more accurately measure the desired system parameters. One such method is the sample-and-hold method where, if a packet is sampled, all subsequent packets in that flow are sampled. Secondly, statistical methods can be used to ``invert'' the sampled data and produce an estimate of flow lengths from a sample. In this paper we propose, implement and test two variants on the sample-and-hold method. In addition we show how the sample-and-hold method can be inverted to get an estimation of the genuine distribution of flow sizes. Experiments are carried out on real network traces to compare standard packet sampling with three variants of sample-and-hold. The methods are compared for their ability to reconstruct the genuine distribution of flow sizes in the traffic

ANALYSIS OF DOMAIN-SPECIFIC NUCLEAR ONTOLOGY USING MONTEREY PHOENIX BEHAVIOR MODELING

Current nuclear energy ontologies are known to lack a common vocabulary to formally verify nuclear energy data relationships for modeling system behaviors. Idaho National Laboratory (INL) developed the Data Integration Aggregated Model and Ontology for Nuclear Deployment (DIAMOND) ontology to provide a standard vocabulary and taxonomy for identifying data relationships in nuclear energy system models. This thesis conducted an analysis of DIAMOND using a Spent Fuel Pool (SFP) Monterey Phoenix (MP) behavior model. The SFP MP behavior modeling application demonstrated components of and interactions among a spent fuel cooling pool and its environment. The MP behavior model demonstrated a viable approach for analyzing nuclear reactor system behavior consistent with DIAMOND and the ability to generate the exhaustive set of nuclear reactor cooling pool behavior scenarios. The results supported the ability of DIAMOND definitions to be used to organize and structure knowledge about SFP’s normal and off-normal behaviors. The SPF example showed the application of assets, actions, and triggers from DIAMOND to events and relationships in MP. Assets and actions were represented as MP events, and triggers were represented as precedence relations between MP events. This thesis research verified the DIAMOND ontology was implemented correctly in the model from data representative of operationally realistic behavior and the modeling results validated the MP behavior model was well constrained.Idaho National LabCivilian, Department of the Air ForceApproved for public release. Distribution is unlimited

Scalable Peer-to-Peer Streaming for Live Entertainment Content

We present a system for streaming live entertainment content over the Internet originating from a single source to a scalable number of consumers without resorting to centralized or provider-provisioned resources. The system creates a peer-to-peer overlay network, which attempts to optimize use of existing capacity to ensure quality of service, delivering low startup delay and lag in playout of the live content. There are three main aspects of our solution: first, a swarming mechanism that constructs an overlay topology for minimizing propagation delays from the source to end consumers; second, a distributed overlay anycast system that uses a location-based search algorithm for peers to quickly find the closest peers in a given stream; and finally, a novel incentive mechanism that encourages peers to donate capacity even when the user is not actively consuming content

Long-lived states of oscillator chain with dynamical traps

A simple model of oscillator chain with dynamical traps and additive white noise is considered. Its dynamics was studied numerically. As demonstrated, when the trap effect is pronounced nonequilibrium phase transitions of a new type arise. Locally they manifest themselves via distortion of the particle arrangement symmetry. Depending on the system parameters the particle arrangement is characterized by the corresponding distributions taking either a bimodal form, or twoscale one, or unimodal onescale form which, however, deviates substantially from the Gaussian distribution. The individual particle velocities exhibit also a number of anomalies, in particular, their distribution can be extremely wide or take a quasi-cusp form. A large number of different cooperative structures and superstructures made of these formations are found in the visualized time patterns. Their evolution is, in some sense, independent of the individual particle dynamics, enabling us to regard them as dynamical phases.Comment: 8 pages, 5 figurs, TeX style of European Physical Journa

Evaluating and Optimising Models of Network Growth

Published versio