Revealing the Tectonic Structure of the Bay of Iskenderun Using the Markov Random Fields Method

One of the important issues in Gravity and Magnetic prospecting is to separate regional and residual anomalies. Determination of this separation between them is also crucial. Markov Random Fields (MRF) method is used to distinguish these anomalies. The most important property of this method is to make use of stochastic characteristic in neighborhood and 2D view. MRF does not need any training before use. This method is first applied to magnetic anomaly map consisting of prisms. After application, MRF method gives satisfactory results. We use Iskenderun Bay magnetic anomaly map to determined off-shore fault lines. According to our results, we reveal fault lines along Iskenderun Bay.

PLANNING OF THE NUMBER OF TESTS WITH ZONAL ESTIMATES OF ARMAMENT AND MILITARY EQUIPMENT

Today, the problem of reducing the cost of resources and time during planning and conducting tests remains relevant. This problem is especially acute in qualified testing agencies, where testing prototypes at different stages of the life cycle is the main functional task. Automation of planning processes and optimization of testing processes will significantly reduce such costs and improve the overall quality of testing. The article considers the theoretical issues of forming quantitative plans for testing samples of armaments and military equipment (AME) in obtaining zonal estimates of stochastic parameters and characteristics. The need for zonal estimates arises to confirm the quality of the sample for a given stochastic characteristic in the range from the allowable probabilistic value to the maximum (minimum) possible. The authors propose an approach to obtaining zonal estimates of the parameters of the armament and military equipment test sample, which theoretically meet the requirements of a given accuracy and reliability. The approach is based on the use of a flexible test plan, which is terminated when statistical confirmation of the probabilistic value not worse than specified by the developer is obtained. Ensuring the quality of evaluation is carried out by virtue of the minimum required number of repetitions of the experiment and the balance of the number of successful to the total number of experiments. It is shown that a flexible test plan can significantly reduce the total number of experiments, which will to some extent reduce the resource and time costs of testing samples of armament and military equipment. For the practical application of the approach of obtaining zonal estimates of the AME sample quality, its formalization and algorithmics is required. It is assumed that the developed approach will be implemented in the form of a functional module as а part of the subsystem of automated planning and quality management of AME sample tests.

A Novel Microwave Staring Correlated Radar Imaging Method Based on Bi-Static Radar System

The stochastic characteristic of the radiation field of a mono-static microwave staring correlated imaging (MSCI) radar degenerates with the increase of the imaging distance, which results in degradation of the image quality. To address this issue, a novel MSCI method based on bi-static radar is proposed from two perspectives: site-deploying and waveform design. On the one hand, a new bi-static MSCI site-deploying scheme is proposed which adopts two transmitting stations with their azimuth angles relative to the center of the imaging region differing by 90 degrees. On the other hand, by using two transmitting arrays synchronously transmitting inner-and-inter pulse frequency hopping (IAIP-FH) signals, the radiation field of each station includes a few “frequency stripes” perpendicular to the radiation direction, and as a consequence, the “frequency stripes” of each radiation field are perpendicular to each other. As a result, the radiation field of the bi-static MSCI is the superposition of the two striped radiation fields, thus a latticed radiation field is constructed. Therefore, the targets in different latticed grids scatter independent fields, then, the images can be reconstructed using correlation process (CP) algorithms. The grid size of the latticed radiation field is determined by the inner-pulse frequency hopping (FH) interval of the IAIP-FH signals and the imaging geometry. Moreover, it is shown that the 3 dB beam width of the space correlation function of the radiation field does not change with the imaging distance, thus the stochastic characteristic of the radiation field is partly preserved when the imaging distance increases. Simulation results validate the analysis and show that the proposed method can obtain higher resolution images than the common mono-static MSCI method.

Nonlinear Stochastic Analysis for Lateral Vibration of Footbridge under Pedestrian Narrowband Excitation

During the lateral vibration of footbridge, the pedestrian lateral load shows two distinct features: one is the vibration-dependency; another is the narrowband randomness caused by the variability between two subsequent walking steps. In this case, the lateral vibration of footbridge is actually a complicated, nonlinear stochastic system. In this paper, a novel nonlinear stochastic model for lateral vibration of footbridge is proposed, in which a velocity-dependent load model developed from Nakamura model is adopted to represent the pedestrian-bridge interaction and the narrowband stochastic characteristic is considered. The amplitude and phase involved Itô equations are established using the multiscale method. Based on the maximal Lyapunov exponent derived from these equations, the critical condition for triggering a large lateral vibration can be obtained by solving the stability problem. The validity of the proposed method is confirmed, based on performing the case studies of two bridges. Meanwhile, through parameter analysis, the influences of several crucial parameters on the stability of vibration are discussed.