Coverage Of State Space Research Articles

A novel negative selection algorithm with hyper-rectangle detectors based on full coverage of state space for anomaly detection

The traditional negative selection algorithm with a randomly generated hypersphere detector is unable to satisfy the development needs of continuous learning due to the inherent defects of the detector. This paper proposes a novel negative selection algorithm for hyper-rectangle detectors that overcomes the shortcomings of randomly generated hyper-sphere detectors and lays the foundation for a negative selection algorithm with continuous learning capability. It uses self-sample clusters of equal-sized hypercubes instead of self-samples for training. The hyper-rectangle detectors are generated by cutting the nonself-space along the boundary of the self-sample clusters. The state space is covered without overlapping each other by self-sample clusters and detectors. The anomaly detection performance of the proposed method was demonstrated using Iris data, vowel recognition data (Vowel), and Wisconsin Breast Cancer (BCW) data. The experimental results show that the proposed method outperforms other artificial immune algorithms and clustering algorithms under the same parameter conditions.

Automated Transient Input Stimuli Generation for Analog Circuits

We present an automated directed random input stimulus generation algorithm with high coverage for nonlinear analog circuits. Our methodology is able to generate input stimuli to meet two kinds of objectives: 1) to reach user-defined goal regions and 2) increased coverage of state space. The principal benefit of our approach is that it can provide directed input stimulus generation, as opposed to the randomly generated input stimulus by Monte Carlo-based methods. The methodology introduces multiobjective rapidly-exploring random trees (MORRTs), which add a bias and a feedback loop to the standard rapidly-exploring random trees algorithm. The biasing is provided by a statistical inference algorithm. Simultaneous biasing toward goal regions and coverage is possible in MORRT to a user-defined extent. Our methodology generates several input stimuli that are concentrated in the goals or relevant operating regions, while providing high coverage of the state space. We demonstrate the efficiency and scalability of our approach on high-dimensional analog case studies.

Crisis bifurcations in plane Poiseuille flow.

Many shear flows follow a route to turbulence that has striking similarities to bifurcation scenarios in low-dimensional dynamical systems. Among the bifurcations that appear, crisis bifurcations are important because they cause global transitions between open and closed attractors, or indicate drastic increases in the range of the state space that is covered by the dynamics. We here study exterior and interior crisis bifurcations in direct numerical simulations of transitional plane Poiseuille flow in a mirror-symmetric subspace. We trace the state space dynamics from the appearance of the first three-dimensional exact coherent structures to the transition from an attractor to a chaotic saddle in an exterior crisis. For intermediate Reynolds numbers, the attractor undergoes several interior crises, in which new states appear and intermittent behavior can be observed. The bifurcations contribute to increasing the complexity of the dynamics and to a more dense coverage of state space.

A coverage metric to evaluate tests for continuous-time dynamic systems

Abstract We present a test quality measure that allows for quantifying the completeness of black-box tests for continuous-time dynamic systems. The measure is based on a state space model of the system under test. The metric has been called the state space coverage. The classical coverage metrics, such as statement, branch, and path coverage, are not appropriate for dynamic systems because such systems are defined by differential equations and usually have an infinite number of states. The objective of the paper is to develop a necessary foundation for the metric as well as to present guidance on its application to software systems that incorporate dynamic behavior. The purpose of the proposed solution is to better assure the test engineer that a given test set is sufficient and to indicate where additional testing is required. An application example is presented to illustrate theoretical analysis and mathematical formulation.

8.3.2 Practical Approach to Increasing State Space Coverage for System Testing

This paper presents a practical solution to improving system level Verification and Validation (V&V) tests, those tests which exercise end‐to‐end functionality of a physical system, for complex hardware/software systems. The proposed method to improve system level testing is to increase the total number of system configurations that are tested in a way such that the state space coverage is explored in a systematic and evenly‐distributed fashion. We describe a method for adapting the combinatorial software test strategy known as t‐wise testing to complex hardware/software systems V&V testing. Practical requirements and potential test selection architecture are provided to demonstrate the utility of the proposed t‐wise testing method. Some methods for test selection and prioritization are outlined for instances when complete t‐wise testing is impractical.

A Pre-Injection Analysis for Identifying Fault-Injection Tests for Protocol Validation

Fault-injection (FI) based techniques for dependability assessment of distributed protocols face certain limitations in providing state-space coverage and also incur high operational cost. This is mainly due to lack of complete knowledge of fault-distribution at the protocol level which in turn limits the use of statistical approaches in deriving and estimating the number of test cases to inject. In practice, formal techniques have effectively being used in proving the correctness of dependable distributed protocols, and these techniques traditionally have not been directly associated with experimental validation techniques such as FI-based testing. There exists a gap between these two well-established approaches, viz. formal verification and FI-based validation techniques. If there exists an approach which utilizing a rich set of information pertaining to the protocol operation generated through formal verification process can provide guided-support to perform FI-based validation, then the overall effectiveness of such validation techniques can be greatly improved. With this viewpoint, in this paper, we propose a methodology which utilizes the theorem-proving technique as an underlying formal-engine, and is composed of two novel structured and graphical representation schemes (interactive user-interfaces) for (a) capturing/visualizing information generated over the formal verification process, (b) facilitating interactive analysis through the chosen formal-engine (any theorem-proving tool) and database, and (c) user-guided identification of influential parameters, those eventually used for generating test cases for FI-based testing. A case study of an on-line diagnosis protocol is used to illustrate and establish the viability of the proposed methodology.