Random Pitch Research Articles

Charged particle reflection in a magnetic mirror

We study the reflection of electrons in a magnetic field mirror. It is a field with a gradient from a lowest value B0 to a largest one Bm. With this purpose, Montecarlo simulations are made. We use a number of 5,000 particles with random pitch angles. The frequency distribution of these random values follows a Gaussian distribution centered at \theta = 0 and with standard deviation \sigma. Various values of \sigma and also different values of the B0 /Bm ratio are used in the simulations. The simulations show that \sigma has an important influence on the confinement of charged particles, for the different B0 /Bm ratios here studied. However, the percent of reflected particles differs from a B0 /Bm ratio to another in the whole range of \sigma, although for \sigma = 10 the differences between different ratios are small (<5%). The number of reflected particles increases very rapidly with \sigma, in the range of 10° to 40°. For the \sigma range from 20° to 40°, the percent of reflected particles is \leq 20% larger for B0 /Bm = 0.10 than for the 0.55 ratio.

The effect of slow wave sleep deprivation on mood in adolescents with depressive symptoms: A pilot study

BackgroundThere is an urgent need for safe, rapid-acting treatment strategies for adolescent depression. In depressed adults, slow wave sleep deprivation (SWSD) improved next-day mood without disrupting sleep duration, but SWSD has not been tested in adolescents. In a pilot study, the aim was to assess the effect of SWSD on sleep physiology and mood outcomes (depression, rumination, anhedonia) among adolescents with depressive symptoms. MethodsSixteen adolescents (17.44 ± 1.46 yr, 12 female) completed three nights of polysomnographic sleep recording: Baseline, SWSD, and Recovery nights. Acoustic stimulation (tones of random pitch, duration, and volume) suppressed slow wave sleep (SWS) in real-time during SWSD. After each night, depression, rumination, and anhedonia severity were assessed. ResultsSWSD successfully suppressed SWS, increased N2, and had minimal impact on Rapid Eye Movement (REM), nocturnal awakenings, and total sleep time. While SWSD did not improve depression or anhedonia severity overall, lower baseline non-REM alpha activity and greater SWS rebound during recovery sleep correlated with SWSD-related reduction in clinician-rated depression severity. Next-day rumination severity decreased after SWSD, with sustained improvements following recovery sleep. However, rumination improvement was not associated with SWS suppression, but rather reduction in total sleep time and REM in exploratory correlation models. LimitationsSmall sample size and large proportion of females. ConclusionSWSD did not improve depression in adolescents overall but a subset with low non-REM alpha activity and intact homeostatic sleep regulation may benefit from this approach. Findings from this pilot study also suggest that partial sleep deprivation may be a beneficial therapeutic strategy for rumination in adolescents.

Neural network-based regression for heat transfer and fluid flow over in-line cylinder arrays with random pitch distances at low Reynolds number

Finding an arrangement, leading to a higher heat transfer and lower pressure drop, is crucial in the design of heat exchangers. Previous studies have primarily focused on regular arrangements with uniform pitch distances, which lack applicability to general configurations. In this study, we proposed a new procedure of a flow-learned building block (FLBB) to predict heat transfer in an in-line cylinder array with random pitch distances using a neural network-based regression analysis with a systematic data generation process. As a first step, we demonstrated the FLBB’s capability to predict the heat transfer and pressure drop in in-line cylinder arrays with random pitch distances at low Reynolds numbers from 1 to 100 for air ( ). Subsequently, a high-order FLBB approach was proposed to address the spatial interdependency between neighbouring cylinders, particularly in scenarios where vortex shedding occurs in the wake of cylinders at increased Reynolds numbers. The high-order FLBB approach was then shown to successfully describe various flow and temperature patterns using cylinder arrays with random pitch distances. The proposed procedure exhibited remarkable efficiency, requiring only about 1 s. Furthermore, the FLBB was successfully extended to various flow regimes, even encompassing unseen Reynolds numbers from 1 to 100.

Application of adaptive fuzzy control to suppression vibration response of floating offshore wind turbine

Floating offshore wind turbine is a complex rigid-flexible coupling nonlinear system, and the accurate dynamic model is difficultly established. Therefore, the wind-wave interference cannot be improved by adopting the conventional control strategy. In order to solve this problem, an adaptive fuzzy controller (AFC) is used to suppress the dynamic response of floating wind turbine. Two correction factors are introduced to optimize the fuzzy rule, and the traditional fuzzy controller (FC) is firstly obtained. Since the balance positions change and structural parameter perturbation of the wind turbine, an AFC is designed and validated. Finally, the suppression vibration responses ability of floating offshore wind turbine by using the different control strategies is studied under the random wind-wave disturbance and blade pitch control system coupling effect. The simulation results show that the tracking ability of the AFC to the target value is obviously higher than that of the FC; Comparing with the passive control strategy, the suppression vibration effect on the power spectral density (PSD) of the platform pitch (PFPI) motion peak can increase by 39.06% by adopting the AFC.

Neural signatures of temporal regularity and recurring patterns in random tonal sound sequences.

The auditory system is highly sensitive to recurring patterns in the acoustic input - even in otherwise unstructured material, such as white noise or random tonal sequences. Electroencephalography (EEG) research revealed a characteristic negative potential to periodically recurring auditory patterns - a response, which has been interpreted as memory trace-related and specific, rather than as a sign of periodicity-driven entrainment. Here, we aim to disentangle these two possible contributions by investigating the influence of a periodic sound sequence's inherent temporal regularity on event-related potentials. Participants were presented continuous sequences of short tones of random pitch, with some sequences containing a recurring pattern, and asked to indicate whether they heard a repetition. Patterns were either spaced equally across the random sequence (isochronous condition) or with a temporal jitter (jittered condition), which enabled us to differentiate between event-related potentials (and thus processing operations associated with a memory trace for a repeated pattern) and the periodic nature of the repetitions. A negative recurrence-related component could be observed independently of temporal regularity, was pattern-specific, and modulated by across trial repetition of the pattern. Critically, isochronous pattern repetition induced an additional early periodicity-related positive component, which started to build up already before the pattern onset and which was elicited undampedly even when the repeated pattern was occasionally not presented. This positive component likely reflects a sensory driven entrainment process that could be the foundation of a behavioural benefit in detecting temporally regular repetitions.

Synthesis of real world drone signals based on lab recordings

There is a great interest in the generation of plausible drone signals in various applications, e.g. for auralization purposes or the compilation of training data for detection algorithms. Here, a methodology is presented which synthesises realistic immission signals based on laboratory recordings and subsequent signal processing. The transformation of a lab drone signal into a virtual field microphone signal has to consider a constant pitch shift to adjust for the manoeuvre specific rotational speed and the corresponding frequency dependent emission strength correction, a random pitch shift variation to account for turbulence induced rotational speed variations in the field, Doppler frequency shift and time and frequency dependent amplitude adjustments according to the different propagation effects. By evaluation of lab and field measurements, the relevant synthesizer parameters were determined. It was found that for the investigated set of drone types, the vertical radiation characteristics can be successfully described by a generic frequency dependent directivity pattern. The proposed method is applied to different drone models with a total weight between 800 g and 3.4 kg and is discussed with respect to its abilities and limitations comparing both, recordings taken in the lab and the field.

Listeners perceive complex pitch-temporal structure in melodies.

In typical Western music, important pitches occur disproportionately often on important beats, referred to as the tonal-metric hierarchy (Prince & Schmuckler, 2014, Music Perception, 31, 254-270). We tested whether listeners are sensitive to this alignment of pitch and temporal structure. In Experiment 1, the stimuli were 200 artificial melodies with random pitch contours; all melodies had both a regular beat and a pitch class distribution that favored one musical key, but had either high or low agreement with the tonal-metric hierarchy. Thirty-two listeners rated the goodness of each melody, and another 41 listeners rated the melodies' metric clarity (how clear the beat was). The tonal-metric hierarchy did not affect either rating type, likely because the melodies may have only weakly (at best) established a musical key. In Experiment 2, we shuffled the pitches in 60 composed melodies (scrambling pitch contour, but not rhythm) to generate versions with high and low agreement with the tonal-metric hierarchy. Both ratings of goodness (N = 40) and metric clarity (N = 40) revealed strong evidence of the tonal-metric hierarchy influencing ratings; there was no effect of musical training. In Experiment 3, we phase-shifted, rather than shuffled, the pitches from the composed melodies, thus preserving pitch contour. Both rating types (goodness N = 43, metric clarity N = 32) replicated the results of Experiment 2. These findings establish the psychological reality of the tonal-metric hierarchy.

Perception of Musical Tension in Cochlear Implant Listeners.

Despite the difficulties experienced by cochlear implant (CI) users in perceiving pitch and harmony, it is not uncommon to see CI users listening to music, or even playing an instrument. Listening to music is a complex process that relies not only on low-level percepts, such as pitch or timbre, but also on emotional reactions or the ability to perceive musical sequences as patterns of tension and release. CI users engaged in musical activities might experience some of these higher-level musical features. The goal of this study is to evaluate CI users' ability to perceive musical tension. Nine CI listeners (CIL) and nine normal-hearing listeners (NHL) were asked to rate musical tension on a continuous visual analog slider during music listening. The subjects listened to a 4 min recording of Mozart's Piano Sonata No. 4 (K282) performed by an experienced pianist. In addition to the original piece, four modified versions were also tested to identify which features might influence the responses to the music in the two groups. In each version, one musical feature of the piece was altered: tone pitch, intensity, rhythm, or tempo. Surprisingly, CIL and NHL rated overall musical tension in a very similar way in the original piece. However, the results from the different modifications revealed that while NHL ratings were strongly affected by music with random pitch tones (but preserved intensity and timing information), CIL ratings were not. Rating judgments of both groups were similarly affected by modifications of rhythm and tempo. Our study indicates that CI users can understand higher-level musical aspects as indexed by musical tension ratings. The results suggest that although most CI users have difficulties perceiving pitch, additional music cues, such as tempo and dynamics might contribute positively to their experience of music.

Using the random components of the jitter of speech pitch period to assess the state of the user of social-cyber-physical system

Socio-cyber-physical systems are focused on perceptual interaction with users and involve analyzing and translating his or her physiological and psycho-emotional state. An actual scientific problem is to determine the latter basing on the user's speech signal. In particular, it can be solved relying on investigating the jitter of the speech pitch period. In this paper we propose an algorithm that allows one to improve the noise immunity of determining the pitch period of speech signal and a method of jitter determination based on averaging the change of the pitch period relatively to the current value. We also propose an algorithm for separating periodic and random pitch jitter based on using the discrete Fourier transform on the sequence of the pitch periods with the presence of unknown values in the unvoiced speech frames. Simulation shows that the proposed approach of filling the unknown values of pitch period has better results compared to the existing methods based on interpolation of the nearest known values.

A putative electrophysiological biomarker of auditory sensory memory encoding is sensitive to pharmacological alterations of excitatory/inhibitory balance in male macaque monkeys.

The amplitude of the auditory evoked N1 component that can be derived from noninvasive electroencephalographic recordings increases as a function of time between subsequent tones. N1 amplitudes in individuals with schizophrenia saturate at a lower asymptote, thus giving rise to a reduced dynamic range. Reduced N1 dynamic range is a putative electrophysiological biomarker of altered sensory memory function in individuals with the disease. To date, it is not clear what determines N1 dynamic range and what causes reduced N1 dynamic range in individuals with schizophrenia. Here we test the hypothesis that reduced N1 dynamic range results from a shift in excitatory/inhibitory (E/I) balance toward an excitation-deficient or inhibition-dominant state. We recorded auditory-evoked potentials (AEPs) while 4 macaque monkeys passively listened to sequences of sounds of random pitch and stimulus-onset asynchrony (SOA). Three independent experiments tested the effect of the N-methyl-d-aspartate receptor channel blockers ketamine and MK-801 as well as the γ-aminobutyric acid (GABA) A receptor-positive allosteric modulator midazolam on the dynamic range of a putative monkey N1 homologue and 4 other AEP components. Ketamine, MK-801 and midazolam reduced peak N1 amplitudes for the longest SOAs. Other AEP components were also affected, but revealed distinct patterns of susceptibility for the glutamatergic and GABA-ergic drugs. Different patterns of susceptibility point toward differences in the circuitry maintaining E/I balance of individual components. The study used systemic pharmacological interventions that may have acted on targets outside of the auditory cortex. The N1 dynamic range may be a marker of altered E/I balance. Reduced N1 dynamic range in individuals with schizophrenia may indicate that the auditory cortex is in an excitation-deficient or inhibition-dominant state. This may be the result of an incomplete compensation for a primary deficit in excitatory drive.

Application of transfer matrix method to calculating the effect of multiple internal reflections on the small signal gain ripple of TWT

The low-signal-gain versus frequency slope is often a highly desirable property of traveling wave tube (TWT) used in a communication system. The gain ripple is usually caused by internal reflexions of forward and backward waves in the TWT. Random fabrication error may have a detrimental effect on the performance of TWT. The quartic equation including backward wave models the effect of reflection to analyze the effect of Gain ripple from many small circuit errors in a TWT operating under small-signal condition. We present a transfer matrix method (TMM) to correctly calculate the transmission and reflection of the wave incident respectively from left and right at a single isolated joint. The TMM, which links the input signal to output signal that includes the feedback signal from the reflections at multiple joints to the output end, can calculate the gain ripple of multiple internal reflections. Appling this method to several numerical examples, we look at how small signal gain is affected by a single isolated discontinuity and many small randomly distributed discontinuities. In particular, we investigate the effects of random perturbations of Pierce velocity detuning parameter b and Pierce gain parameter C on the small signal gain at different values of space charge 4QC. The computed result agrees with that from Chernin's model. We find that reflections may significantly increase the statistical effects on the gain. A further conclusion is that the standard deviation of gain, dgain, increases with b gradually, but the ratio of the backward wave power to the forward wave power at x=0 decreases with b when standard deviation of pierce velocity detuning parameter, b, is more than 1.5. In another example, the effects of two discontinuities of pitch distribution and many small random pitch errors on gain ripple are reported for a G-band TWT. We find that larger pitch error and longer distance for the discontinuities may produce a larger ripple in the small-signal-gain versus frequency. Many small discontinuities may produce a large gain ripple, and the gain ripple grows as the level of pitch error increases. These effects of random fabrication errors become increasingly important for very high frequencies, such as 1 THz, at which TWTs are currently being designed and built.

Effect of Electrode Shape and Current Source on Performance of Electrocoagulation

AbstractElectrocoagulation is a versatile technique used for treating various types of industrial effluent. The material of the construction and shape of the electrodes are crucial in the electrocoagulation process. The effect of the electrode shape on the performance of the electrocoagulation has been studied by performing experiments for the removal of the dye from the synthetic dye solution using punched electrodes and the results have been evaluated in terms of color removal efficiency. The effect of the number of holes, the diameter of the hole, and the configuration of the holes (square, triangular, and random pitch of the holes) on the color removal efficiency was investigated. An increase in the color removal efficiency was obtained using the punched electrode compared with the plane electrode. The effect of the current source (direct and alternating current) on the performance of the electrocoagulation was studied and no significant effect of the current source on the performance of the electroco...

Kalman-PD Control for Depth System of Autonomous Underwater Vehicle

A Kalman-PD depth controller was designed for depth system of AUV, and the controller was simulated on MATLAB/ SIMULINK. Performance of the controller was observed with actuator saturation, random pitch sensor noise and random fin disturbances. At the same time, response of a conventional PID controller for depth closed loop was also given for comparison. Results show that the Kalman-PD controller gives well performance in dealing with the noisy and disordered depth control system of AUV.

픽셀 배치가 자유로운 임베디드 LED 전광판 모듈 및 제어장치 설계

본 논문에서는 적색, 녹색, 청색의 세 가지 고휘도 LED를 하나의 소켓에 설치하여, 하나의 화소체 단위를 만들고, 이 화소체들의 조합과 다수 모듈들의 조합으로 문자, 그래픽, 동영상 등의 다양한 영상을 표출할 수 있는 풀컬러 전광판 모듈 및 제어장치를 개발하였다. LED 전광판 드라이버 모듈은 일정한 단위 면적에 RGB 픽셀을 조합한 도트에 드라이버 회로가 내장된다. 기존의 이러한 모듈형태는 특정 공간 및 설치 공간에 고정된 해상도를 구현하므로 가격이 높게 책정될 수 있다. 이러한 단점을 극복하기 위하여 임의의 피치 간격으로 배열이 자유로운 LED 드라이버 및 이에 따른 LED 픽셀 모듈을 개발하였다. 본 논문의 전광판 모듈은 기존 각각의 LED 모듈을 구동함에 있어서 병렬 방식의 데이터 처리 방식을 픽셀을 기준으로 그 위의 서브 모듈과 그 상위에 마스터 모듈의 개념을 도입하고 각각의 화소를 직병렬 통신 방식으로 개선함으로 인해서 처리할 수 있는 데이터의 속도를 초당 36프레임 이상으로 끌어올려서 상대적으로 데이터의 처리량이 많은 동화상의 경우에도 원활한 디스플레이를 할 수 있도록 하였다. 또한 기존 전광판의 깜박거림 현상이 개선되어 보다 선명한 영상이 제공되는 효과도 있다.

Effects of Multiple Internal Reflections on the Small-Signal Gain and Phase of a TWT

We formulate and solve a set of equations that model the effects of reflections from an arbitrary number of circuit discontinuities in a traveling-wave tube (TWT) operating under small-signal conditions. Applying this model to a case in which the discontinuities represent a series of small random pitch variations due to fabrication errors in a helix TWT, we find that reflections may significantly increase the statistical effects on the gain and output phase first reported in the work of Pengvanich In another example, we report on a study of the effects of many small pitch errors on gain ripple in a 220-GHz folded waveguide TWT.

Compressive Sensing Based on Deterministic Sparse Toeplitz Measurement Matrices with Random Pitch

Selecting an appropriate measurement matrix is one of the key points of compressive sensing.Due to randomly introducing zero elements into these matrices to form sparse Toeplitz matrices with random pitch,the number of random independent variables can be reduced to 1/2 and 1/16 less than that of original Toeplitz matrices,the number of nonzero elements can also be reduced significantly,which is conducive to data transmission and storage.Simulation results show that the reconstructions of sparse Toeplitz measurement matrices with random pitch are better than Gaussian and original Toeplitz matrices.Moreover,the time of reconstruction is only about 15% to 40% of the time of Gauss and general Toeplitz reconstruction.

随机间距稀疏三元Toeplitz矩阵相位掩模压缩成像

随机间距稀疏三元Toeplitz矩阵相位掩模压缩成像

Stochastic rocket dynamics under random nozzle side loads: Ornstein-Uhlenbeck boundary layer separation and its coarse grained connection to side loading and rocket response

A long-standing, though ill-understood problem in rocket dynamics, rocket response to random, altitude-dependent nozzle side-loads, is investigated. Side loads arise during low altitude flight due to random, asymmetric, shock-induced separation of in-nozzle boundary layers. In this paper, stochastic evolution of the in-nozzle boundary layer separation line, an essential feature underlying side load generation, is connected to random, altitude-dependent rotational and translational rocket response via a set of simple analytical models. Separation line motion, extant on a fast boundary layer time scale, is modeled as an Ornstein-Uhlenbeck process. Pitch and yaw responses, taking place on a long, rocket dynamics time scale, are shown to likewise evolve as OU processes. Stochastic, altitude-dependent rocket translational motion follows from linear, asymptotic versions of the full nonlinear equations of motion; the model is valid in the practical limit where random pitch, yaw, and roll rates all remain small. Computed altitudedependent rotational and translational velocity and displacement statistics are compared against those obtained using recently reported high fidelity simulations [Srivastava, Tkacik, and Keanini, J. Applied Phys., 108, 044911 (2010)]; in every case, reasonable agreement is observed. As an important prelude, evidence indicating the physical consistency of the model introduced in the above article is first presented: it is shown that the study's separation line model allows direct derivation of experimentally observed side load amplitude and direction densities. Finally, it is found that the analytical models proposed in this paper allow straightforward identification of practical approaches for: i) reducing pitch/yaw response to side loads, and ii) enhancing pitch/yaw damping once side loads cease.

Restraint of tool path ripple based on surface error distribution and process parameters in deterministic finishing

The influence from the regular tool path to micro fabrication errors in deterministic finishing is studied through the simulations and experiments. The random pitch tool path based on the surface error distribution and the process parameters is designed to reduce this residual error when adopting the regular path to achieve the corrective polish. A nucleated glass flat mirror is polished with this method on the experimental installation UPF700-7 developed by ourselves. The surface accuracy is improved from the initial λ/30(RMS, 90%aperture, λ = 632.8 nm) to the final λ/200 in 5 minutes and the medium-high spatial frequency errors induced by the regular path is restricted well at the same time. The accuracy of the simulation and the validity of the random pitch tool path are both proved through the experiments.

Reaction, Anticipation and Accent in a Gravitational Pitch Space: Commentary on Ammirante and Thompson

Ammirante and Thompson's intriguing article aims to enhance the ecological validity of their previous findings (Ammirante, Thompson, & Russo, in press) by using music-like melodic stimuli, rather than random pitch sequences. In line with this aim, I will briefly discuss three issues that may be taken into account in relating the motion-like qualities of melody to music and music-related behavior (finger tapping). First, I suggest how the authors' hypotheses may be examined within a context in which tapping is affected by expectancies for a specific melodic continuation. Second, I discuss how timing and velocity changes associated with melodic distance and contour may give rise to a prototypical joint accent structure, integrating melodic, agogic and dynamic accent. Finally, I note a possible confound of melodic direction and tonality in Ammirante and Thompson's stimuli, and suggest ways to examine the effects of these two dimensions separately.