Using the MPM93 model, the L-band of atmospheric radiation parameters and salinity meter observation brightness temperature under different weather conditions are numerically simulated based on the microwave radiation transfer equation, and using the maximum likelihood estimation algorithm to the inversion of sea surface salinity, which research the influence of different weather conditions on the sea surface salinity retrieval value. The simulation results show that the atmospheric radiation parameters of cloud, fog and haze which considered the effects of suspended droplets are almost the same as those in clear sky, and the influence of them can be neglected. However, the influence of rainfall on atmospheric radiation parameters can’t be neglected, and the error of salinity retrieval increases obviously with the increase of rainfall rate. When the rainfall rate is fixed, the salinity inversion error decreases with the increase of sea surface temperature, and the salinity retrieval error is smaller under low salinity value. Besides, the salinity retrieval error changes decrease after increasing with the increase of sea level atmosphere temperature. Furthermore, the influence of sea surface windspeed, sea level pressure and sea level vapor density on salinity retrieval error are very small.

A digital decimation filter applied to audio Sigma-Delta ADC is designed. The filter adopts the design of multi-stage and multi-rate down sampling structure, in-band ripple of decimation filter is less than 0.06 dB overall, bandwidth is 21.6 kHz, minimum working frequency is 10 MHz. Through the innovation of filter hardware architecture design, it effectively reduces the filter circuit area and power consumption. Chip test results show that the SNR is above 87.2 dB when processing PDM signals is at the down sampling rate of 64, 4 order Sigma-Delta modulation. Designed in SMIC’s 0.13 μm CMOS process, the decimation filter area is 0.146 mm². Filter area is reduced by 58%, and power consumption is reduced by over 60% compared with the same type decimation filters.

The authors present a time-to-digital converter based on multi-stage amplification structure. This structure consists of coarse stage and fine stage. Coarse stage utilizes delay line to get the residue which is less than a buffer’s delay. A small area and low power residue selecting logic is designed. In the fine stage, 2× time amplifier and half judger is utilized to generate 4 binary codes from MSB to LSB. Simulation in SMIC 65 nm process shows that the new structure has a high conversion speed up to 470 MS/s and power consumption is 1.3 mW at 100 MHz with the resolution of 1.44 ps and range of 736 ps. An accurate gain robust to PVT variation can be achieved with the calibration of the time amplifier, so a good integral nonlinearity is obtained.

Based on the traditional hardware implementations of Kalman filter, the authors derive and simplify the filtering formulas according to the filtering model and matrix operations, and then design underlying FPU (float point unit) needed by the filtering formulas according to the “bottom-up” design thinking, to implement the complete Kalman filter system. The Kalman filter designed by this method not only gets rid of dependence on third-party platforms and increase the portability and application areas of filtering system, but the filtering speed improves significantly than traditional matrix operation method. For a constant acceleration filtering model, this paper provides detailed data comparison between formula derivation method and traditional matrix operation method, the Kalman filter designed by this method maintains the accuracy of the previous level and achieves the computing speed 2.1 times, compared with the traditional matrix operation method.

A low noise amplifier (LNA) for Beidou navigation system was designed through the standard GaAs pHEMT technology. This circuit had the operating frequency of 2.45 GHz and noise figure of 0.55 dB. ESD protection circuit was added through the input and output matching network. Finally ADS2011 was used to simulate the design. According to the comparison of the circuit with ESD protection and that without ESD protection, the conclusion can be drawn that the circuit with ESD protection will induce some decline of the performance, such as the gain drawn from 16 dB down to 15 dB, but the noise has no change; with the ESD protection, the circuit can be greatly improved in overall performance and robustness, and the circuit has good resistance to electrostatic interference.

The authors present the mechanism of spatial data active updating derived by GECA (geographical event-condition-action) rules to improve the level of spatial data updating automatization. Modeling and expressing spatio-temporal variations process of geographical feature is the key of active updating. The geographical event is as a concept entity for describing dynamic changes and dynamic processing of geographical feature. The authors propose a geographical event model for spatial data active updating emphatically based on conceptual model and predication expression, and design the database logical expression frame and the detection and storage flow for geographical event. Proved by the example for settlement places and roads, this kind of model can describe the dynamic spatio-temporal changes of entity in the process of data updating effectively also with the function of history retrospect. At last, the active updating example is presented, the result indicate that the mechanism can improve the efficiency of updating.

Kirzhnits method is extended in the gradient expansion of the Dirac density matrix of a many electron system to the two dimension case. The zeroth-order and second-order expansion for the Dirac density matrix in two dimensions is derived. From it, the expansion for the density and kinetic energy are further derived. The results show that, in contrast to the case of the three dimensions, to the second order of the gradient expansion, there is only the Laplacian type of term Δ²k_F², while the gradient term of (Δk_F²)² is absent in the two dimensional case. The result should be useful in the application of density functional theory to two dimensional systems.

A queueing system GI^X/M/1/N with balking and batch arrivals was discussed. The interarrival and service times are arbitrarily and exponentially distributed, respectively. The distributions of the number of customers in the system at prearrival and arbitrary epochs are obtained. In addition, some performance metrics are given, such as the customer loss rate, the system utilization, the mean and variance of the queue length, the mean of the waiting time. Some application scenarios on computer communication network are discussed concerning this queueing system.