The line-of-sight multiple-input multiple-output (LOS-MIMO) has emerged as a potential solution for increasing spectral efficiency in dense urban microwave links, given limited spectrum resources. Phase variation and power attenuation may introduce uncertainty to the channel estimation, affecting channel capacity and the performance of interference cancellation by zero-forcing receivers. This paper investigates the impact of this uncertainty in the presence of rain. Commercial backhaul links (CMLs) in cellular networks are not only essential for data transmission but have also proven useful for rainfall monitoring. They are now emerging as a new opportunistic integrated sensing and communication (OISAC) application for weather sensing. This paper also studies the use of LOS-MIMO backhaul technology for rain rate estimation. The availability of multiple data streams allows the number of rain estimation values to increase linearly with the minimum number of transmit and receive antennas in the MIMO link, Additionally, the potential for LOS-MIMO microwave links to retrieve parameters related to rain drop size distribution based on measurement data is also explored. This new backhaul solution shows great potential to be used for near-ground environmental monitoring and weather prediction studies, particularly with the advent of the big data era.

Commercial microwave links (CMLs) are used to transmit information between base station towers in cellular networks. Opportunistic remote sensing of rainfall, using the signal level measurements from CMLs, has proven to be highly accurate in rain rate estimation. As traditional CML link has single antenna and polarization setup, its capability of retrieving other precipitation parameters is limited. The latest microwave technology line-of-sight multiple-input multiple-output (LoS MIMO) are equipped with multiple transmitters and receivers to increase capacity. In a 2x2 LOS-MIMO system, each of the two antennas employs a different polarization. In this study, we investigate the potential of using LOS-MIMO microwave link to retrieve parameters related to rain drop size distribution based on measurement data.

With high accuracy and stability of GPS radio occultation data in the stratosphere, COSMIC data is used to validate the Microwave Temperature Sounder (MWTS) channel 4 (57.29GHz, shorted for ch4) brightness temperature (TB) measures on FY3A/3B in 2011-2012. We also introduce AMSU-A TB observations on NOAA satellites to further investigate the TB differences and their possible causes. Finally, a correction method is proposed for MWTS ch4. The results show that the differences between observed (O) and simulated (M) TB of MWTS ch4 are more significant than the corresponding AMSU-A differences. The distributions of TB differences (O-M) between AMSU-A and MWTS are similar at high latitudes; at mid-latitudes and the tropics MWTS observations are significantly higher than not only the simulated TB, but also the AMSU-A observations, and in particular in the tropics, the TB measurements at MWTS ch4 are significantly higher than AMSU-A ch9 by 1-5 K, which suggests that the discrepancy is mainly due to the data quality of MWTS ch4 itself. Comparisons of the MWTS ch4 TB before and after using correction method show that the correction is most effective in the tropics and the mid-latitudes, especially in the tropic the significantly higher TB deviation of about 2-3 K was reduced to 0-1 K after the correction, and the corrected TB differences are reduced in all four latitude zones.

In this paper, real outdoor measurements were conducted to examine the performance of spatially separated 2×2 line-of-sight multiple-input multiple-output (LOS-MIMO) backhaul deployments at millimeter-wave frequency in city environment. The performance of the backhaul link transmission and received signal level are analyzed over a period in both sunny and rainy weather. We study the variations of signal propagation due to rain and compare the performance with theoretical rain model given by ITU. The impact of wet antenna attenuation and other uncertainties are analyzed based on the measurement data.

Cloud mask products are essential for the retrieval of aerosol and cloud properties as well as in understanding the impacts of clouds on the Earth's radiation budget and global climate change. This paper evaluates the Moderate Resolution Imaging Spectroradiometer (MODIS) cloud mask products through comparison with four years of ground-based radar data over Beijing. Different data collocation schemes are applied to analyze and thoroughly understand the differences between the MODIS and the radar. Comparison results show that the agreement of cloud mask between the MODIS and radar is 84%. There are 11% comparisons of which the MODIS is cloudy while radar is clear because of their different field of view. It is found that the missed thin clouds by MODIS account for 5% of the disagreement and discrepancies are mostly due to thin clouds.

Radar actively detects cloud internal physical structure while a radiometer passively measures the integral radiation characteristics of cloud. This study used cloud products from CloudSat (active detection) and AQUA (passive detection) to study the relationships between the variations of radiation characteristics and the physical structure characteristics of cloud. It was found that variations of cloud radiation illustrated a monotonic change to the variations of physical structures when conditions had little change. This means two cloud profiles with close radiative properties may also have close physical structures. For cloudy profiles with unknown internal structures, their vertical structures could then be inferred from other cloudy profiles with similar spectral radiative properties.

Adaptation is one of the most important phenomena in biology. A young barn owl can adapt to imposed environmental changes, such as artificial visual distortion caused by wearing a prism. This adjustment process has been modeled mathematically and the model replicates the sensory map realignment of barn owl superior colliculus (SC) through axonogenesis and synaptogenesis. This allows the biological mechanism to be transferred to an artificial computing system and thereby imbue it with a new form of adaptability to the environment. The model is demonstrated in a real-time robot environment. Results of the experiments are compared with and without prism distortion of vision, and show improved adaptability for the robot. However, the computation speed of the embedded system in the robot is slow. A digital and analog mixed signal very-large-scale integration (VLSI) circuit has been fabricated to implement adaptive sensory pathway changes derived from the SC model at higher speed. VLSI experimental results are consistent with simulation results.

Visual and auditory map alignment in the superior colliculus (SC) of the barn owl is important for its accurate localization of prey. The visual map, and hence the alignment, may be purposefully disturbed in a juvenile barn owl by fitting it with ocular prisms, and it is found that it can adapt its auditory map to this mismatch after several weeks training. In our previous SC model, the axon growing process is instructed by an inhibitory network, the strength of which is adjusted using the neural structures involved in spatial localization. Based on this model, a mixed signal integrated circuit of the SC has been designed, and simulation results are consistent with those found by biological experiment. This new model makes possible artificial networks capable of eliminating the disparity between the visual and auditory maps.

We present a simple neuromorphic central pattern generators (CPG) circuit module, which is essentially a pair of coupled oscillators, to actuate a joint on a leg. This novel, reconfigurable CPG module is able to generate different motor patterns of different frequencies or duty cycles, simply by changing a few of circuit parameters. Three CPG modules, corresponding to three joints, can make an arthropod leg of three degrees of freedom (DOFs). With appropriate circuit parameter settings, and thus suitable phase lags among joints, the leg is expected to walk on a complex terrain with adaptive steps. The adaptation is associated with the circuit parameters mediated by external commands or sensory signals. Simulation results for the circuitry, designed using a 0.35 mum process, are reported.

To localize a seen object, the superior colliculus of the barn owl integrates the visual and auditory localization cues which are accessed from the sensory system of the brain. These cues are formed as visual and auditory maps, thus the alignment between visual and auditory maps is very important for accurate localization in prey behavior. Blindness or prism wearing may disturb this alignment. The juvenile barn owl could adapt its auditory map to this mismatch after several weeks training. Here we investigate this process by building a computational model of auditory and visual integration with map adjustment in the deep superior colliculus. The adaptation is based on activity dependent axon developing which is instructed by an inhibitory network. In the inhibitory network, the strength of the inhibition is adjusted by spike timing dependent plasticity(STDP). The simulation results are in line with the biological experiment and support the idea that the STDP is involved in the alignment of sensory maps. The system of the model provides a new mechanism capable of eliminating the disparity in visual and auditory map integration.

The visual and auditory map alignment in the Superior Colliculus (SC) of barn owl is important for its accurate localization for prey behavior. Prism learning or Blindness may interfere this alignment and cause loss of the capability of accurate prey. However, juvenile barn owl could recover its sensory map alignment by shifting its auditory map. The adaptation of this map alignment is believed based on activity dependent axon developing in Inferior Colliculus (IC). A model is built to explore this mechanism. In this model, axon growing process is instructed by an inhibitory network in SC while the strength of the inhibition adjusted by Spike Timing Dependent Plasticity (STDP). We test and analyze this mechanism by application of the neural structures involved in spatial localization in a robotic system.