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Water level is an important indicator of wetland hydrological regime. Detection of wetland water levels through interferometric synthetic aperture radar (InSAR) has outstanding advantage, including high spatial resolution, high accuracy, low cost, and high efficiency. We introduced prerequisites for the monitoring of wetland water levels with InSAR, discussed the types of InSAR techniques, the influencing factors for monitoring wetland water levels and their advantages and disadvantages. There are three prerequisites for effectively detecting wetland water levels with InSAR techniques: 1) the presence of emergent aquatic plants; 2) the main backscattering mechanism is double bounce scattering; and 3) the interferometric coherence exceeds a certain threshold. Current water level monitoring techniques have been developed from traditional InSAR techniques to advanced InSAR techniques, such as STBAS, MM, and DSI. These techniques evolve from detecting relative water level changes to estimate absolute water level and water depth time series. The influencing factors of InSAR techniques for monitoring wetland water levels include operating para-meters of the synthetic aperture radar (SAR) and characteristics of the wetlands themselves. Finally, we proposed the key directions for future research in this field: i) investigating the potential use of specific water level monitoring techniques in other regions with different backscattering and interferometric coherence characteristics; ii) developing new algorithms to integrate multi-sensor, multi-track, multi-band, multi-polarization, and multi-temporal InSAR repeat-pass observation; iii) considering alternative sources of SAR data; and (iv) strengthening research on "by-products" of wetland water level monitoring with InSAR, such as wetland hydrological connectivity, flow direction, and flow regime.

Objective: To compare the effect of impulse-radio ultrawideband（IR-UWB） radar technology and polysomnography（PSG） in sleep assessment. Method: A total of 79 OSA patients were randomly divided into two groups: 40 patients in group A received PSG and IR-UWB, and 39 patients in group B received micromovement sensitive mattress（MSM） and IR-UWB. Pearson correlation and ROC curve were used for statistics. Result: AHI PSG and AHI MSM were significantly correlated with AHI IR-UWB（ r =0.91, P ＝0.00; r =0.92, P ＝0.00）. Bland-Altman analysis showed that AHI IR-UWB value was highly consistent with AHI PSG value（95.00%）, and AHI IR-UWB value（97.44%）. The sensitivity and specificity of AHI IR-UWB compared with PSG were 70.40% and 89.90%, respectively. The area under ROC curve was 0.915. Conclusion: IR-UWB has a high diagnostic value for adult OSA in terms of minimum blood oxygen saturation, average blood oxygen saturation, average number of central sleep apnea, average number of complex sleep apnea, average heart rate, sleep efficiency, REM sleep duration, average AHI, etc. It is an economic and practical sleep evaluation tool., Competing Interests: The authors of this article and the planning committee members and staff have no relevant financial relationships with commercial interests to disclose., (Copyright© by the Editorial Department of Journal of Clinical Otorhinolaryngology Head and Neck Surgery.)

This paper introduces the theory of short-time FFFT? as well as the wavelet transform, and uses this theory to analyze the monitoring of weak signal of radar in strong-noise background. The corresponding basic-function and discrete algorithm are also given. Finally, the simulation result is provided by computer. [ABSTRACT FROM AUTHOR]

To non-contact alarm the sleep apnea under low physical and mental load condition a device was designed including the modules of minimized bio-radar, signal conditioning, control, alarm and power supply, which can realize the function of non-contat detection of the breathing signal, sleep apnea detection and alarm. Experimental results showed that the device can not only non-contact detection the breathing signal without any sensors or electrodes touching the human body, but also has the advantages of smal volume, low power consumption and low price, which may be widely used in monitor the patients with sleep apnea at home or in the hospital.

Non-contact vital sign detection technique provides an effective usage in health monitoring applications. A vital sign detector was designed based on microwave bio-radar technique. Using Doppler principle, continuous wave bioradar was designed for tiny body movement detection, short-time Fourier transform and interpolation algorithm were adopted for heart and respiration rate extraction, embedded system was used for system integration, real-time signal processing software was designed on it. Experiments were done by using simulation device and human body for research and performance evaluation. The result shows that the proposed prototype can be used for single target vital signs detection at the distance of 90 cm, and the heart rate result shows a 96% recognition rate.

Objective: To study the effects of radar radiation on sperm quality., Methods: A total of 348 infertile seamen were divided into 4 experimental groups according to their different lengths of exposure to radar radiation: Group 1 (n = 128) exposed for 12-36 months, Group 2 (n = 58) 37-72 m, Group 3 (n = 47) 73-108 m, Group 4 (n = 19) 109 m or more and Group 5 (n = 96) 48 m or more but free from the exposure for 6 months by then. Another 35 non-marine normal males were recruited as Control Group 1, and the first four experimental groups (n = 252) were taken as Control Group 2. Semen samples were collected from the subjects and analyzed statistically., Results: Compared with the normal control, sperm concentration, sperm motility and the percentage of grade a sperm were significantly lower (P < 0.01), and the percentages of grade d and abnormal sperm significantly higher (P < 0.01) in the experimental groups. In Group 5, obvious recovery was noted in sperm morphology (P < 0.01) and motility (P < 0.05), but significant differences were seen with the normal control group in sperm concentration (P < 0.05), sperm motility and the percentage of grade a and b sperm and that of abnormal sperm (P < 0. 01)., Conclusion: Radar radiation damages sperm quality, as shown in the reduction of sperm motility and elevation of sperm abnormality. Cease from the exposure may effect an easy recovery in sperm morphology.

Objective: To evaluate the effect of Long-term exposure to low intensity microwave radiation on male reproductivity., Methods: A total of 289 married male radar operators were included in the radar group and 148 married men unexposed to microwave radiation were enrolled as controls. Questionnaires were used and the intensity of microwave radiation in different working areas was detected., Results: The rate of sexual dysfunction was 43.6% in the radar group and 24.4% in the control group (P < 0.01). The natural pregnancy rate was 53.6% within 1 year of marriage and 46.4% after 1 year of marriage in the radar group, as compared with 81.1% and 18.9% in the control group (P < 0.01)., Conclusion: Long-term exposure to low intensity microwave radiation evidently increased the sexual dysfunction rate and decreased natural pregnancy rate in men.

To determine whether a living object is human being or animal by detecting the respiration signal using the life-detector based on radar to penetrate the building or debris. To fully utilize the nonstationary character of the respiration signal, short time Fourier transform (STFT) is employed to get the signal's time-frequency representation. Singular value decomposition (SVD) is then used in the spectrogram to extract feature vector for pattern identification. Human beings and animals can be identified from the respiration sensed by the life-detector based on radar. Experimental results show that the method based on STFT and SVD is stable and efficient to differ from the human being and animal.

This paper approached the feasibility of quantitatively monitoring Dendrolimus spp. damage by using NOAA/ AVHRR data. The damaged rate of needle leaf was used to represent Dendrolimus spp. harming degree, and < 30%, 30%-60% and > 60% of damaged rate was defined as low, medium and severe harming degree, respectively. The correlation equation of damaged rate and normalized vegetation index (NDVI) was established, based on the ground spectrum observation. The NDVI was 0.8823 when no damage occurred. A relative NDVI value of damaged to undamaged area was used to express the remote sensing index of low, medium and severe harming degree. The index was 1 for undamaged forest, and 0.78-1, 0.57-0.78 and < 0.57 for low, medium and severe harming degrees, respectively. The mixed pixels were separated by linear addable vertical vegetation index in the monitoring, and the quantitative monitoring and analysis was accomplished for years when the three damage degrees happened. It was shown that AVHRR data could be more available in quantitatively monitoring and analyzing serious damage, while low degree damage was difficult to distinguish by AVHRR data, due to the differences of surface properties and atmospheric influences, as well as the lower space resolution of NOAA/AVHRR. The damaged area estimated by AVHRR was 12.1%-14.3% lower than that by TM.

Objective: To investigate the relationship between microwave radiation and male reproductivity., Methods: After filling out questionnaire and body check, we carried out molecular epidemiological studies, using single cell gel electrophoresis (SCGE) and sperm automatic analysis among people working on radar., Results: Quality of semen and semi-clinical injury of sperm among the people working on radar had changed when radar electromagnetic wave frequency distance, intensity, lasting time and protection shield were changing. Dose-response relationship was noticed and the increase of sperm dysmorphia played a principal role. The results between exposed group and control group showed significant difference (P < 0.01)., Conclusion: People working on radar who suffered from non-ionization for long time and had bad radar shield protection would show semi-clinical injury on sperm and bad semen quality. However, it did not affect the male reproductive function. It was necessary to reinforce the protection of non-ionization and to improve male reproductive health care of people working on radar.

Objective: To evaluate the inflicted by radar electromagnetic radiation to the sperm DNA of radar operators., Methods: Sperm concentration, viability, motility, sperm abnormality were determined by routine sperm analysis and sperm chromatin structure assay (SCSA) in the highly exposed group(n = 88), lowly exposed group(n = 143) and control group(n = 39)., Results: Sperm motility, viability of the highly exposed group reduced compared with that of the lowly exposed group and control group, while sperm abnormality increased. The COMP alpha reduction of the highly exposed group indicated that the highly exposed group had a medium fertility potential. The multifactor variable analysis showed that daily working time was a dangerous factor in sperm abnormality and abstinence time was a dangerous factor in the parameter of SCSA., Conclusions: Radar radiation inflicts damage to male reproduction system and it is important to take protective measures.

A method for compressing the noises overlapping in the breath and heart signals of human beings, detected by the non-contact vital signs detecting system during the display of the waveforms in time domain, is discussed in this paper in detail. And what's more, the problem that the noise level is changed along with the increase of the gain of AD data-acquisition card and the display--gain of the software is solved by researching into the threshold of noise-level contraction in two types of circumstance in the lab, and the result of the breath and heart signal in the condition of lower noise is realized as well.

The paper introduces the design of hardware and software of non-contact detection system for breathing and heartbeat in human body with radar principles and technology. The detection technology is discussed. Under conditions of the illuminating power P < 1 mW and the distance S < 10 m, the non-contact breathing and heartbeat measurement, can be in different positions and with different clothing on the subject. The results show that the system with the technology has a high sensitivity, and is harmless to the health. It is a practicable non-contact detection technology for breathing and heartbeat of human body.

This paper reports serum vitamin A (VA) content of 28 radar operators, and the effects of supplementation VA were studied by means of observing change of serum VA level and objective dark adaptation time. The results indicated, with respect to serum VA content, 14.3% of radar operators had a deficient level (less than 10 micrograms%), whereas 57.2% of radar operators had a low level (less than 20 micrograms%). There were 39.3% of radar operators who had a low level on nineteenth day and 92.9% of radar operators who had a acceptable value on twenty-eighth day after oral VA supplementation VA of 3,000 IU, suggesting that supplementation VA of 3,000 IU to radar operators with VA malnutrition for about one month is necessary. A certain correlation between serum VA level and objective dark adaptation time was also observed.