Random Shot Research Articles

Urchar Bodaigh i bPoll Móna (‘A Random Shot’) and Other Irish Sayings

This article engages with various Irish phrases and sayings such as urchar bodaigh i bpoll móna (‘a random shot’) and demonstrates how particular terms have been lexicographically described by Dineen and Ó Donaill. Irish expressions have embodied terms with multiple meanings that contribute to the complexity of various expressions and how various terms can be paired together. Lexicographers note the widespread deployment of the words bod and bodach (and a range of related terms) to spawn, in various combinations, a swathe of terminology relating to aspects of the natural world and the firmament. The disparate and versatile lexical capacity of bod and bodach and their derivatives adumbrated in botanical, icthyological, ornithological, meteorological and astronomical nomenclature is quite striking, not least because of its sexual dimensions.

The effect of narrative coherence and visual salience on children’s and adults’ gaze while watching video

Low-level visual features (e.g., motion, contrast) predict eye gaze during video viewing. The current study investigated the effect of narrative coherence on the extent to which low-level visual salience predicts eye gaze. Eye movements were recorded as 4-year-olds (n = 20) and adults (n = 20) watched a cohesive versus random sequence of video shots from a 4.5-min full vignette from Sesame Street. Overall, visual salience was a stronger predictor of gaze in adults than in children, especially when viewing a random shot sequence. The impact of narrative coherence on children’s gaze was limited to the short period of time surrounding cuts to new video shots. The discussion considers potential direct effects of visual salience as well as incidental effects due to overlap between salient features and semantic content. The findings are also discussed in the context of developing video comprehension.

Ionization phase retrieval by angular streaking from random shots of XUV radiation

We demonstrate an accurate phase retrieval of extreme ultraviolet (XUV) atomic ionization by streaking the photoelectron in a circularly polarized infrared (IR) laser field. Our demonstration is based on a numerical solution of the time-dependent Schr\"odinger equation. We test this technique using the hydrogen atom ionized by isolated attosecond XUV pulses across a wide range of the photon energies. Importantly, the proposed method works in a random shot mode when the time delay between the ionizing and streaking XUV and IR pulses may vary from shot to shot. This is a significant advantage over the existing interferometric techniques which require a systematic and controllable scan of the XUV and IR delay in one set of measurements. Such a scan may not be possible to take because of the arrival time jitter inherent to the stochastic nature of self-amplified free-electron laser radiation.

The Effect of compound exercises using the (RANDOM SHOT) device and the electronc goal ln developing the speed of the motor response and the rapid ability of the two goal keepers youth football halls

The research problem shaped through the entry of complex exercises with the introduction of scientific devices as a Random Shot, and the electronic goal when applying goalkeepers exercises for the national football team for halls. Through the experience of the researchers in the field and academic field, and on students, researchers and personal interviews with football coaches, as well as their follow up on the training course. The two researches noticed that there was a variation in the movement response and ability of the goalkeepers' feet. This may be attributed to the lack of interest of trainers in training these two abilities. As well as, the lack of equipment and tools that accompany exercises which allow for diversity and change to occur, it is regarded as one of the important rules in training. Therefore, this study came to shed light on such exercises according to the scientific foundations that are related to the actual training components that are related to the characterized by physical and movement capabilities for the purpose of bringing about development in the level of these capabilities for goalkeepers by introducing training methods and assistive devices like the electronic goal and Random Shot. As well as, applying complex exercises accompanied by audio and visual effects to spread enthusiasm and move away from boredom and monotony for the trainees in an effort to develop the physical and movement side. An objective of research and monotony for the trainers were preparing compound exercises using Random Shot and electronic goal in developing the speed of the motor response and the rapid ability of the feet of the football goalkeepers for halls. As for imposing search, there are statistically significant differences between the results of the pre and post-tests of the kinetic response and rapid ability to the feet of the goalkeepers of the youth football team for halls. As for the research sample was deliberately chosen, consisted of four goalkeepers where the reconnaissance experiment was conducted on two goalkeepers within the research sample. After that, pretests were conducted for the research sample, and then, apply exercises using assistive devices where they were implemented in the main part of the training unit, with 24 units divided into 3 training units per week for a period of 2 months. After that, the posttests of the research sample were performed. Statistical methods were used to process the data. The two researchers concluded that combined exercises using devices helped effectively to develop the speed of movement response and the rapid ability of football goalkeepers feet for halls. One of the most important recommendations is the necessity of using modern training methods and the emphasis on the aspect of developing the speed of movement response and rapid ability of the goalkeeper, because it is one of the most physical characteristics on which the defensive and offensive duties of a goalkeeper depend

Quantum Error Mitigation using Symmetry Expansion

Even with the recent rapid developments in quantum hardware, noise remains the biggest challenge for the practical applications of any near-term quantum devices. Full quantum error correction cannot be implemented in these devices due to their limited scale. Therefore instead of relying on engineered code symmetry, symmetry verification was developed which uses the inherent symmetry within the physical problem we try to solve. In this article, we develop a general framework named symmetry expansion which provides a wide spectrum of symmetry-based error mitigation schemes beyond symmetry verification, enabling us to achieve different balances between the estimation bias and the sampling cost of the scheme. We show that certain symmetry expansion schemes can achieve a smaller estimation bias than symmetry verification through cancellation between the biases due to the detectable and undetectable noise components. A practical way to search for such a small-bias scheme is introduced. By numerically simulating the Fermi-Hubbard model for energy estimation, the small-bias symmetry expansion we found can achieve an estimation bias 6 to 9 times below what is achievable by symmetry verification when the average number of circuit errors is between 1 to 2. The corresponding sampling cost for random shot noise reduction is just 2 to 6 times higher than symmetry verification. Beyond symmetries inherent to the physical problem, our formalism is also applicable to engineered symmetries. For example, the recent scheme for exponential error suppression using multiple noisy copies of the quantum device is just a special case of symmetry expansion using the permutation symmetry among the copies.

Full waveform inversion with random shot selection using adaptive gradient descent

Full waveform inversion (FWI) is a powerful yet computationally expensive technique that can yield subsurface models at high resolution. Randomly selected shots (mini-batches) can be used to approximate the misfit and the gradient of FWI, thereby reducing its computational cost. Here, we present a methodology to perform mini-batch FWI using the Adam algorithm, an adaptive optimization scheme based on stochastic gradient descent. It provides for stable model updates by smoothing the gradient across iterations and can also account for the curvature of the optimization landscape. We describe empirical criteria to choose the hyperparameters of the Adam algorithm and the optimal mini-batch size. The performance of the outlined scheme is illustrated on synthetic data from the Marmousi model and compared with conventional full-batch FWI. FWI with random shot selection and optimized by the Adam algorithm exhibits rapid convergence and yields superior results compared to conventional FWI implemented with the l-BFGS method.

Ultra-long-haul digital coherent PSK Y-00 quantum stream cipher transmission system.

A record-long 10,118-km fiber transmission with physical layer encryption is demonstrated utilizing a Y-00 cipher based on signal masking by quantum (shot) noise. The Y-00 cipher enables symmetric-key data encryption to ensure the security of the physical layer of optical communications. Irreducible secrecy without significant negative impact on transmission performance is achieved by the synergistic effect of combining seed-key-based high-order modulation and truly random shot noise inevitable in optical detection. This paper reports a comprehensive study of applying a phase-shift-keying (PSK) Y-00 cipher for ultra-long haul fiber transmission. Theoretical analysis shows that security-enhanced transmission over transoceanic-distance (>10,000 km) fiber is feasible when the quadrature PSK data signal is encrypted by converting to a PSK signal with 218 levels. Subsequently, 10,118-km standard single-mode fiber transmission of 48-Gbit/s line-rate dual-polarization PSK Y-00 cipher with 218 levels is experimentally demonstrated. An adequate signal quality above the Q-factor threshold of soft decision forward error correction is achieved together with sufficient signal masking by shot noise, yielding balanced transmission performance and high security in an ultra-long-haul PSK Y-00 cipher transmission system.

Shot peening effects on residual stresses redistribution of offshore wind monopile multi-pass weldments

In some industrial applications, welding is the only alternative to join different parts. However, the major problem in welded structures is the tensile residual stresses that are inevitably produced during welding process. Surface tensile stresses can threaten the performance of the weldments as they act as an accelerant in fatigue crack initiation and failure. Shot peening is a well-known method which can enhance weldments' fatigue performance and longevity by inducing surface compressive residual stresses in order to eliminate or limit tensile residual stresses.In this study, the effect of shot peening on redistribution of multi-pass welding residual stresses was numerically and experimentally investigated on very large components typical of welded joints used in offshore wind turbine monopiles. In experimental part of the study, the residual stresses were measured using the Incremental Centre Hole Drilling (ICHD) method before and after shot peening. Finite element studies were carried out using 3D welding models and random shot peening analyses. Moreover, extensive finite element analyses were conducted to study the effect of model dimensions and the number of passes on prediction of welding residual stresses. Interesting set of results obtained from both the numerical studies and the ICHD measurements were in good agreements and showed that shot peening can be advantageous even for large components with multi-pass welded joints. Additionally, reducing the number of weld passes in finite element models could considerably lower the computational time without affecting the accuracy of results at surface regions of the models.

Management of the scrotal trauma caused by an air-compressed gun in a child: A case report

Children exposed to air gun pellets may also have a different clinical picture, from mild tissue damage to life-threatening injury. Although these weapons are known as toys, in recent years, there has been a significant increase in the muzzle velocity of these weapons with advances in gas technology. Air gun injuries are frequently presented in the head, neck and thorax region, but injuries in the genitourinary tract are rare in children. Here, we report a 12-year-old boy who was injured by a random shot with an air gun, due to the features of his diagnosis and treatment.

Effect of sequential video shot comprehensibility on attentional synchrony: A comparison of children and adults

To comprehend edited video, viewers must infer the meaning conveyed by successive video shots (i.e., continuous video segments separated by edit points, such as camera cuts). The central question here was whether comprehension-related top-down cognitive processes drive eye movements during sequential processing of video montage. Eye movements were recorded as 4 year olds and adults (n = 62) watched a video with the same constituent shots in either normal or random sequence. The key analyses compared eye movements to constituent shots when presented in normal order with those to the same shots presented in random order. The dependent variable was attentional synchrony or the extent to which viewers looked at the same location at the same time, indicating commonality of processing the video. This was calculated as the bivariate contour ellipse area within which points of gaze fell during each video frame. Results indicated that children were more scattered in their gaze locations than adults. Viewers became more similar to each other as normal vignettes unfolded over time; this was especially true in adults and possibly reflects a growing and shared understanding of the content. Conversely, adult attentional synchrony was reduced when watching random shot sequences. Thus, attentional synchrony during normal video viewing is driven not only by salient visual features, such as movement and areas of high contrast, but also, by the unfolding sequential comprehension of video montage, especially in adults. Differences between children and adults indicate that this top-down control of eye movements while watching video changes systematically over development.

Detection of small-amplitude periodic surface pressure fluctuation by pressure-sensitive paint measurements using frequency-domain methods

Image measurement using pressure-sensitive paint (PSP) is an effective tool for analyzing the unsteady pressure field on the surface of a body in a low-speed air flow, which is associated with wind noise. In this study, the surface pressure fluctuation due to the tonal trailing edge (TE) noise for a two-dimensional NACA 0012 airfoil was quantitatively detected using a porous anodized aluminum PSP (AA-PSP). The emission from the PSP upon illumination by a blue laser diode was captured using a 12-bit high-speed complementary metal-oxide-semiconductor (CMOS) camera. The intensities of the captured images were converted to pressures using a standard intensity-based method. Three image-processing methods based on the fast Fourier transform (FFT) were tested to determine their efficiency in improving the signal-to-noise ratio (SNR) of the unsteady PSP data. In addition to two fundamental FFT techniques (the full data and ensemble averaging FFTs), a technique using the coherent output power (COP), which involves the cross correlation between the PSP data and the signal measured using a pointwise sound-level meter, was tested. Preliminary tests indicated that random photon shot noise dominates the intensity fluctuations in the captured PSP emissions above 200 Hz. Pressure fluctuations associated with the TE noise, whose dominant frequency is approximately 940 Hz, were successfully measured by analyzing 40,960 sequential PSP images recorded at 10 kfps. Quantitative validation using the power spectrum indicates that the COP technique is the most effective method of identification of the pressure fluctuation directly related to TE noise. It is possible to distinguish power differences with a resolution of 10 Pa $$^2$$ (4 Pa in amplitude) when the COP was employed without use of another wind-off data. This resolution cannot be achieved by the ensemble averaging FFT because of an insufficient elimination of the background noise.

Multi-Aperture-Based Probabilistic Noise Reduction of Random Telegraph Signal Noise and Photon Shot Noise in Semi-Photon-Counting Complementary-Metal-Oxide-Semiconductor Image Sensor.

A probabilistic method to remove the random telegraph signal (RTS) noise and to increase the signal level is proposed, and was verified by simulation based on measured real sensor noise. Although semi-photon-counting-level (SPCL) ultra-low noise complementary-metal-oxide-semiconductor (CMOS) image sensors (CISs) with high conversion gain pixels have emerged, they still suffer from huge RTS noise, which is inherent to the CISs. The proposed method utilizes a multi-aperture (MA) camera that is composed of multiple sets of an SPCL CIS and a moderately fast and compact imaging lens to emulate a very fast single lens. Due to the redundancy of the MA camera, the RTS noise is removed by the maximum likelihood estimation where noise characteristics are modeled by the probability density distribution. In the proposed method, the photon shot noise is also relatively reduced because of the averaging effect, where the pixel values of all the multiple apertures are considered. An extremely low-light condition that the maximum number of electrons per aperture was the only 2 was simulated. PSNRs of a test image for simple averaging, selective averaging (our previous method), and the proposed method were 11.92 dB, 11.61 dB, and 13.14 dB, respectively. The selective averaging, which can remove RTS noise, was worse than the simple averaging because it ignores the pixels with RTS noise and photon shot noise was less improved. The simulation results showed that the proposed method provided the best noise reduction performance.

Measurement error analysis of Brillouin lidar system using F–P etalon and ICCD

Brillouin lidar system using Fabry–Pérot (F–P) etalon and Intensified Charge Coupled Device (ICCD) is capable of real time remote measuring of properties like temperature of seawater. The measurement accuracy is determined by two key parameters, Brillouin frequency shift and Brillouin linewidth. Three major errors, namely the laser frequency instability, the calibration error of F–P etalon and the random shot noise are discussed. Theoretical analysis combined with simulation results showed that the laser and F–P etalon will cause about 4MHz error to both Brillouin shift and linewidth, and random noise bring more error to linewidth than frequency shift. A comprehensive and comparative analysis of the overall errors under various conditions proved that colder ocean(10°C) is more accurately measured with Brillouin linewidth, and warmer ocean (30°C) is better measured with Brillouin shift.

Fundamental limitations to high-precision tests of the universality of free fall by dropping atoms

Tests of the universality of free fall and the weak equivalence principle probe the foundations of General Relativity. Evidence of a violation may lead to the discovery of a new force. The best torsion balance experiments have ruled it out to 10^-13. Cold-atom drop tests have reached 10^-7 and promise to do 7 to 10 orders of magnitude better, on the ground or in space. They are limited by the random shot noise, which depends on the number N of atoms in the clouds. As mass-dropping experiments in the non-uniform gravitational field of Earth, they are sensitive to the initial conditions. Random accelerations due to initial condition errors of the clouds are designed to be at the same level as shot noise, so that they can be reduced with the number of drops along with it. This sets the requirements for the initial position and velocity spreads of the clouds with given N. In the STE-QUEST space mission proposal aiming at 2x10^-15 they must be about a factor 8 above Heisenberg's principle limit, and the integration time required to reduce both errors is 3 years, with a mission duration of 5 years. Instead, offset errors at release between different atom clouds are systematic and give rise to a systematic effect which mimics a violation. Such offsets must be demonstrated to be as small as required in all drops, must be small by design and must be measured. For STE-QUEST to meet its goal they must be several orders of magnitude smaller than the size of each individual cloud, which in its turn must be at most 8 times larger than the uncertainty principle limit. Even if all technical problems are solved and the clouds are released with negligible systematic errors, still they must be measured. Then, Heisenberg's principle dictates that the measurement lasts as long as the experiment and the systematic nature of the effect requires many measurements for it to be ruled out as a source of violation.

Effect of initial surface finish on effectiveness of shot peening treatment using enhanced periodic cell model

In this paper, we investigate the effect of the initial surface finish of the target on shot peening effectiveness using realistic 3D finite element simulations. Specifically, a large number of random shot impingements were simulated using an enhanced periodic cell model. The target material which is made from TI-6Al-4V is assumed to be strain-rate sensitive and follows the kinematic hardening law. ABAQUS/PYTHON scripts were developed to average the peening residual stresses at each depth of the target, and to calculate the corresponding surface roughness. The simulation was validated by comparing the results with the published work in literature. The periodicity of the model was also examined and verified. The model is further used to investigate the effect of the initial surface roughness on the effectiveness of the shot-peening treatment. The evolutions of the residual stress, plastic strain and the surface morphology during the peening process have all been investigated and the results discussed. The work reveals that a rough surface finish can lead to major reduction in the effectiveness of the shot peening treatment in terms of the generation of the highly beneficial compressive residual stresses.

The Theoretical Analysis and Design of Coding BOTDR System With APD Detector

The signal-to-noise ratio and the coding gain of Brillouin optical time domain reflectometry system with APD detector are analyzed. In coding distributed optical fiber sensing system, there are a large number of multipath interferences (MPIs), which are proportional to the code length. The random shot noise caused by MPI will be generated before decoding and cannot be eliminated by decoding process. In addition, the shot noise power is proportional to the square of the code length; the thermal noise power increases linearly with the code length, then, the increase of the speed of the coding gain will be decreased with the increase of the code length. When the shot noise is much larger than the thermal noise, the coding gain will not be increased with the increase of the code length, but will maintain a constant value. This conclusion is in contradiction with the traditional conclusion. At the same time, the shot noise depends on the pulsewidth and power, but the thermal noise is independent on the pulsewidth and the power, so there exists an optimum code length for specific system.

Evolution of efficient real-time non-linear image filters for FPGAs

Image processing represents a research field in which high-quality solutions have been obtained using various soft computing techniques. Evolutionary algorithms constitute a class of stochastic search methods that are applicable in both optimization and design tasks. In the area of circuit design Cartesian Genetic Programming has often been utilized in combination with an algorithm of Evolutionary Strategy. Digital image filters represent a specific class of circuits whose design can be performed by means of this approach. Switching filters are advanced non-linear filtering techniques in which the main idea is to detect and filter the noise pixels while keeping the uncorrupted pixels unchanged in order to increase the quality of the resulting image. The aim of this article is to present a robust design technique based on Cartesian Genetic Programming for the automatic synthesis of switching image filters intended for real-time processing applications. The robustness of the proposed evolutionary approach is evaluated using four design problems including the removal of salt and pepper noise, random shot noise, impulse burst noise and impulse burst noise combined with random shot noise. An extensive evaluation is performed in order to compare the properties of the evolved switching filters with the best conventional solutions. The evaluation has shown that the evolved switching filters exhibit a very good trade off between the quality of filtering and the implementation cost in field programmable gate arrays.

Shot noise systems with random relaxations

We explore a model of a random relaxation shot noise system in which (i) the shot inflow is a general Poisson point process, with possibly infinite Poissonian rates; and (ii) the exponential relaxations governing the shot decay are randomized. This system model is applicable to physical environments polluted by radioactive contamination of heterogeneous types. The statistics of random relaxation shot noise systems are analyzed quantitatively and comprehensively: stationary structure, correlation structure, process distribution, fractality and asymptotic fractality, and the display--both separately and simultaneously--of the Noah and Joseph effects. Results are obtained explicitly and in closed form, and facilitate the design of tractable shot noise systems with unique features.

Image reconstruction in optical tomography in the presence of coupling errors

Image reconstruction in optical tomography is a nonlinear and generally ill- posed inverse problem. Noise in the measured surface data can give rise to substantial artifacts in the recovered volume images of optical coefficients. Apart from random shot noise caused by the limited number of photons detected at the measurement site, another class of systematic noise is associated with losses specific to individual source and detector locations. A common cause for such losses in data acquisition systems based on fiber-optic light delivery is the imperfect coupling between the fiber tips and the skin of the patient because of air gaps or surface moisture. Thus the term coupling errors was coined for this type of data noise. However, source and detector specific errors can also occur in noncontact measurement systems not using fiber-optic delivery, for example, owing to local skin pigmentation, hair and hair follicles, or instrumentation calibration errors. Often it is not possible to quantify coupling effects in a way that allows us to remove them from the data or incorporate them into the light transport model. We present an alternative method of eliminating coupling errors by regarding the complex-valued coupling factors for each source and detector as unknowns in the reconstruction process and recovering them simultaneously with the images of absorption and scattering. Our method takes into account the possibility that coupling effects have an influence on both the amplitude and the phase shift of the measurements. Reconstructions from simulated and experimental phantom data are presented, which show that including the coupling coefficients in the reconstruction greatly improves the recovery of absorption and scattering images.

Cortical Activation While Watching Video Montage: An fMRI Study

Comprehending edited film or video that depicts visual action requires complex perceptual and cognitive activities to appreciate the flow of action through space and time across sequences of shots. We hypothesized that these complex events are associated with the coordinated activities of multiple brain areas that are not activated by random sequences of shots. Using functional magnetic resonance imaging (fMRI), a distributed cortical network was identified that is uniquely activated during viewing of normal video action sequences, but not by sequences of random video shots or by highly scrambled video image sequences. This cortical network includes extrastriate, inferotemporal, parietal, posterior cingulate, and frontal areas and are predominantly in the right hemisphere. Notably, though there was no activation of classical, left hemisphere language areas, there was activation in the right hemisphere homologues of left hemisphere language areas. In all anatomical areas but 1 in the identified network, there was nearby activation during the random shot sequences. This exception, activated only by normal, coherent shot sequences, was in the posterior cingulate (Brodmann area 31). The comprehension of edited visual action sequences that are typical of contemporary film and video formats appears to be based upon the coordinated activities of multiple brain areas that are bound together functionally in a high-level cognitive network.