Noise Effects in the Mode-Locked External Cavity Lasers

Effect of high level of spontaneous and carrier noise on mode-locked hybrid soliton pulse source and relative intensity noise is described. Transform limited pulses are not generated over a wide frequency range because of these noises.

A Study of Extra-auditory Effects of Noise

Paper mill workers (106) exposed to noise ranging from 80 to 96 dBA were assessed foralteration in clinical status. Neurobehavioral functions were examined with the help of aquestionnaire. The study did not reveal any changes attributable to noise in subjectsexposed to 86-90 dBA and )90 DBA noise in course of their occupations.

Noise-induced synchronous stochastic oscillations in small scale cultured heart-cell networks

This paper reports that the synchronous integer multiple oscillations of heart-cell networks or clusters are observed in the biology experiment. The behaviour of the integer multiple rhythm is a transition between super- and sub- threshold oscillations, the stochastic mechanism of the transition is identified. The similar synchronized oscillations are theoretically reproduced in the stochastic network composed of heterogeneous cells whose behaviours are chosen as excitable or oscillatory states near a Hopf bifurcation point. The parameter regions of coupling strength and noise density that the complex oscillatory rhythms can be simulated are identified. The results show that the rhythm results from a simple stochastic alternating process between super- and sub-threshold oscillations. Studies on single heart cells forming these clusters reveal excitable or oscillatory state nearby a Hopf bifurcation point underpinning the stochastic alternation. In discussion, the results are related to some abnormal heartbeat rhythms such as the sinus arrest.

STATISTIC PROPERTIES OF NOISE FIELD OF MOVING SOURCE IN SHALLOW WATER AND ITS EFFECTS ON SIGNAL PROCESSING FOR THE NOISE RANGING SONAR

In this paper the properties of space- time correlation function of the noise field of moving source in layered statistic inhomogeneous medium are studied and the effects of random fluctuating boundary are considered as well.It has been shown, theoretically and experimentally, multi-path propergating effects cause the dispersion of the correlation function and fluctuations of the medium refraction index and the boundary cause the fluctuation of it.The effect of the movement of the noise source on the output of real- time correlator is equivalent to a low- pass filter added the drift of space- time correlation function.These properties of the correlation function cause grave degradation of the signal processing gain of noise ranging sonar system.The fluctuating and the distortion of conrrelation function made it difficult to realize the noise ranging.So in this paper, a method of space correlation ranging by a linear array of four points with short separation and long span and a technigue of dual- correlation signal processing are presented. By this, the influences of previously mentioned factors are greatly overcomed.Futhermore, for the long period and great delay fluctuation of the dual- correlation function output caused by internal wave, a method of limited memory Quasi- Kalman filtering is developed and the effective accurate ranging and tracing of noise ranging sonar are able to be tralized finally.

Effects of traffic noise on pupils'behavior in classroom

Noise surveys in this country reported that a large number of classrooms in primary and secondary schools in the urban areas were disturbed by environmental noise, particularly by traffic noise. A series of psychological tests were conducted to identify pupils' behavior in a classroom under different noise levels within the range of 40 to 70 dBA. Statistical analysis results were obtained by using Relational Data Analysis System (RDAS) software. According to the t-test and single factor variance analysis of the results, significant differences of the pupils' behavior in the classroom have been observed when the percentile exceeded sound level either L50 exceeds 50 dBA or L10 exceeds 55 dBA, or the equivalent continuous sound level Leq exceeds 50 dBA. The same conclusion has been drawn from the average percentages of syllable articulation under different noise levels in a classroom which were the results of tests made in accordance with the procedure described in the National Standard. The maximum acceptable noise level in the classroom thus can be determined.

The Effect of Lateral Guiding Mechanism on Noise Characteristics in Semiconductor Lasers

A comparison between intensity noise spectra and also the line shapes of gain-guided, weakly-index-guided, and strongly-index-guided semiconductor lasers are made using numerical solution of Maxwell-Bloch equations including spontaneous emission noise.

Effect of cutting process on machine tool noise

Based on the principle of Statistical Energy Analysis (SEA) for non-conservatively coupled systems under general excitations, relationship between noise radiated from and excitations on coupled complex structures is studied, which lays a foundation for the determination of noise/vibration energy by evaluation of exciting forces, and from that the quantitative analysis of the effects of an excitation on sound power from a sub-structure can be done. With extending of the relationship to the study of cutting noise, regression analysis method for evaluating the effects of cutting process on machine tool noise is established. Results show that cutting process has generally negligible effects on machine tool noise, and there is no apparent difference between machine tool noise in cutting condition and in idle one.

Complimentary return-freight insurance serves the dark side: An innovative online return policy in China

E-commerce is a typical form of retail digitalization that introduces online uncertainty and product returns.To decrease the negative influence of online uncertainty,the largest Chinese e-commerce company,the Alibaba Group,invited an insurance company to develop return-freight insurance(RFI),a new kind of insurance,to compensate for consumers'losses in the event of online product returns.Complimentary RFl can increase consumer confidence in the retailer and attract more demand.Retailers who offer complimentary RFI demonstrate to consumers that their products and services are too good to incur excessive product returns.However,some low-quality online retailers can mimic competitors'behavior by offering complimentary RFI to consumers.This study aims to introduce an innovative online return policy based on RFI and to explore whether lowquality online retailers would use complimentary RFI as their return strategy to mislead consumers.Using signaling theory,we built a conceptual economic model that includes three exogenous pricing variables:RF,insurance premium,and compensation.These variables play different roles in the model because consumers cannot observe the insurance premium,but the compensation can be.The main finding of this study is that innovative complimentary RFI could be abused by low-type retailers when the premium and compensation are appropriate.Interestingly,compensation plays different roles for retailers with different product values:low-type retailers use complimentary RFI as a noise tool.When the product works for the consumer and the insurance profit is not too high,the compensation for the low-quality product should be larger than that for the highquality product,which is different from conventional wisdom.Although high-type online retailers may use complimentary RFl as a product quality signal,there is still a significant risk that nefarious elements will use it to create product quality noise.