Abstract: A system and methods for displaying data distribution information for time-series data is described. The methods include computing a condensed quantile function that may be used to generate approximate histograms for the time-series data, while decreasing the data storage requirements for generating a series of histograms for time-series data. The methods further include displaying the data distribution information using stack-bar histograms, many of which may be shown in a single display to permit a user to discern trends in the data distribution information. Methods for merging condensed quantile function tables are also described.

Abstract: A sub-system is provided to a discrete event simulator (DES) to expedite simulation execution by first detecting a non-quiescent steady-state condition in the simulated system, and when the steady-state condition is detected, the simulator determines a state, and subsequently simulates the system at a skip-ahead time using this determined state, or a predicted state based on the determined state. Convergence analysis is used to determine whether the system is at, or approaching, a steady-state condition. This convergence skip-ahead process achieves faster analysis by avoiding the computation that would conventionally be required to simulate the system behavior during the time interval that is skipped.

Abstract: A method and system for flow propagation analysis uses ‘tracers’ that are iteratively propagated through a simulated network between source and destination elements. These tracers are structured to contain traffic flow information from source to destination, and to reflect changes as the flow is affected by each element along the path from source to destination. The resultant flow information at the destination corresponds to the effective throughput from the source to the destination, and the flow information at the output of each intermediate element in the network corresponds to the potentially achievable throughput through that element for the given source-to-destination flow.

Abstract: A system and method for dynamically generating alarm thresholds for performance metrics, and for applying those thresholds to generate alarms is described. Statistical methods are used to generate one or more thresholds for metrics that may not fit a Gaussian or normal distribution, or that may exhibit cyclic behavior or persistent shifts in the values of the metrics. The statistical methods used to generate the thresholds may include statistical process control (SPC) methods, normalization methods, and heuristics.

Abstract: Methods and an apparatus for instrumenting object oriented software that do not require modification to existing source code or to executable files, nor do they require modification to any existing sequences of object resident instructions. Methods include the class interceptor, doppelganger and method hijacking software instrumentation techniques. The class interceptor technique intercepts and monitors the paths of execution associated with methods inherited by a target class. The class doppelganger technique intercepts and monitors the paths of execution entering a target class. The method hijacking technique creates and adds instrumented methods directly to a target class.

Abstract: A simulation system and method that combines the advantages of both analytical modeling and discrete-event simulation is disclosed. In a preferred embodiment of this invention, traffic on the network is modeled as a combination of background-traffic and explicit-traffic. The background-traffic is primarily processed in an analytical form, except in the “time-vicinity” of an explicit-event. Explicit-events are processed using discrete-event simulation, and the modeled effects are dependent upon the background-traffic. At each occasion that the background-traffic may affect the explicit-traffic, the background-traffic is particularized into events that are modeled at the lower detail level of the explicit-traffic.

Abstract: A method, an apparatus, and a computer-readable medium for performing a discrete-event simulation employs an event list comprising events. In the event list, one event is indicated as a head event, and each event is indicated as uncomputed, pre-computed, or in-computation. An uncomputed event is selected and transferred to one of at least one event pre-computation processes, which computes a computation for the selected uncomputed event. An uncomputed head event is executed, and a pre-computed head event is verified.