A Distributed Cooperative Localization Algorithm for Mobile Multi-platforms Oriented to Unpredicted Communication Topology

The cooperative localization(CL)is affected by the communication topology among the platforms.Based on the unscented Kalman filtering,the distributed CL(DCL)oriented to the unpredicted communication topology is investigated.To improve the adaptability,the character of the look-up Cholesky decomposition is exploited for the covariance matrix decomposing.Then,the distributed U transformation can be dynamically implemented according to the available communication topology.In the proposed algorithm,the global information is not required for the individual,and only the available information from the neighbor is used.Each platform’s state can be estimated independently.The error covariance of the state estimates can be updated in the single platform.The algorithm is adaptive to any serial communication topologies where the measuring to the measured platform is a starting path.The applicability of the proposed algorithm to unpredicted communication topology is improved,remaining equivalent localization performance to free connection communication.

Analysis on Multi-Platform Intelligent Control System based on FPGA under IOT Environment

With the continuous development of networking technology, sensor networks have been widely used and has become an important field of information technology infrastructure, especially the real-time sensor networks provide the perceptual information for many intelligent applications provides sufficient information to support decision-making and the necessary basis. However, due to the intelligent application-aware, real-time information demands often cannot be converted to simple queries and query interface to sensor substrate exact match, With the development of technology, people’s expectations of the home and the definition of the family conferred no longer adhere to the traditional way of life, smart home has become a hot spot in recent years, the direction of research in the field of information technology. Embodied herein Things smart home design is based on FPGA technology, capable of real-time collection of the temperature, humidity and light intensity and other information, to achieve environmental control systems, intelligent fish gardening systems, intelligent catering systems, multimedia control systems and security alarm systems function, provide users with the new smart home networking experience.

A New Multi-platform Data Acquisition System for Power Quality Metrological Certification

In order to provide power quality monitoring activities with metrological certification, a DAS （data acquisition system） has been designed, realized and characterized. The system allows acquisition on tri-phases plus neutral lines picking up 499 samples per period of the fundamental at 50 Hz. To ensure certified measurements, the system gets external certified time and voltage references. The system uses a FTDI Virtual Com Port Driver to communicate data over High Speed RS232 virtual interface and it does not need any advanced programming skill. The choice to use a virtual serial communication makes the data acquisition software portable over many platforms, regardless by the development environment and by the programming language. To test the proposed device some custom software have been written in many programming language （C^#, VB6, LabView, MatLab）, moreover in order to characterize the device the most common ADC （analog to digital converter） performing test have been applied.

利用超声相控阵的油中局部放电定位实验分析

局部放电定位检测是电气设备绝缘机理研究与质量监控的关键项目,是状态维修的重要基础。局部放电的超声阵列定位方法从理论上实现了对传统超声定位方法的有效改进,但在实验研究中往往会遇到由于阵列传感器多阵元耦合性能不一致、多次测向结果不一致以及双平台测向交叉定位原理不合理等导致定位成功率低及定位精度下降的实际问题。为此,提出了3种实用方法与技术对其进行改进和完善:一是采用铅笔芯测试技术进行超声相控阵多阵元的耦合性能测试,提高定位成功率;二是对同一位置采取多次测向、加权平均的方法提高同一位置测向精度;三是采用多平台测向、全局搜索定位的方法提高局放源的定位精度。最后,搭建了一套基于超声相控阵的油中局部放电定位实验系统,开展实验研究。实验结果表明,定位误差<10 cm,验证了上述3种方法可以有效提高局放超声阵列定位的成功率及定位精度。

A 12bit 300MHz Current-Steering CMOS D/A Converter

The proposed DAC consists of a unit current-cell matrix for 8MSBs and a binary-weighted array for 4LSBs,trading-off between the precision,speed,and size of the chip.In order to ensure the linearity of the DAC,a double Centro symmetric current matrix is designed by the Q2 random walk strategy.To achieve better dynamic performance,a latch is added in front of the current switch to change the input signal,such as its optimal cross-point and voltage level.For a 12bit resolution,the converter reaches an update rate of 300MHz.

基于SWAN模式的“灿鸿”台风浪数值模拟

以第三代海浪模式SWAN(simulating wave nearshore,近岸海浪数值模型)为基础,构建了东中国海海域波浪数值模式,并以高时间、空间分辨率的CCMP(cross calibrated multi-platform,多平台交叉校正)风场作为驱动风场进行波浪计算,模拟了1509号"灿鸿"台风的波浪过程。同时,对SWAN模式中的底摩擦参数化方案、波浪破碎参数、风能输入与白冠耗散、波-波非线性相互作用等因素对台风浪模拟的影响进行了分析,并对模式中的各影响因素给出了建议。模拟结果与浮标实测有效浪高数据(舟山朱家尖站、南麂岛站、舟山外海站、温州外海站)两者之间的偏差较小,表明本研究所建立的模式以及选择的参数合理,SWAN和CCMP风场的结合能满足海洋波浪数值模拟的需求。本研究对于台风浪数值预报具有参考意义。

Framework of SAGI Agriculture Remote Sensing and Its Perspectives in Supporting National Food Security

Remote sensing, in particular satellite imagery, has been widely used to map cropland, analyze cropping systems, monitor crop changes, and estimate yield and production. However, although satellite imagery is useful within large scale agriculture applications （such as on a national or provincial scale）, it may not supply sufifcient information with adequate resolution, accurate geo-referencing, and specialized biological parameters for use in relation to the rapid developments being made in modern agriculture. Information that is more sophisticated and accurate is required to support reliable decision-making, thereby guaranteeing agricultural sustainability and national food security. To achieve this, strong integration of information is needed from multi-sources, multi-sensors, and multi-scales. In this paper, we propose a new framework of satellite, aerial, and ground-integrated （SAGI） agricultural remote sensing for use in comprehensive agricultural monitoring, modeling, and management. The prototypes of SAGI agriculture remote sensing are ifrst described, followed by a discussion of the key techniques used in joint data processing, image sequence registration and data assimilation. Finally, the possible applications of the SAGI system in supporting national food security are discussed.

ON HOMOGENEOUS RIEMANN BOUNDARY VALUE PROBLEMS OF HIGHER DEGREE

General solution for homogeneous Riemann problems of higher degree is considered. By introducing the concept of loop as well as cross-point, the problem is solved in detail for the quadratic case. The cubic and the quartic ones are also analysed.

Trends of sea surface wind energy over the South China Sea

Studies on climate change typically consider temperature and precipitation over extended periods but less so the wind. We used the Cross-Calibrated Multi-Platform (CCMP) 24-year wind fi eld data set to investigate the trends of wind energy over the South China Sea during 1988-2011. The results reveal a clear trend of increase in wind power density for each of three base statistics (i.e., mean, 90 th percentile and 99 th percentile) in all seasons and for annual means. The trends of wind power density showed obvious temporal and spatial variations. The magnitude of the trends was greatest in winter, intermediate in spring, and smallest in summer and autumn. A greater trend of increase was found in the northern areas of the South China Sea than in southern parts. The magnitude of the annual and seasonal trends over the South China Sea was larger in extreme high events (i.e., 90 th and 99 th percentiles) compared to the mean conditions. Sea surface temperature showed a negative correlation with the variability of wind power density over the majority of the South China Sea in all seasons and annual means, except for winter (41.7%).

Numerical simulation and preliminary analysis on ocean waves during Typhoon Nesat in South China Sea and adjacent areas

Using the wave model WAVEWATCH III(WW3), we simulated the generation and propagation of typhoon waves in the South China Sea and adjacent areas during the passage of typhoon Nesat(2011). In the domain 100°–145°E and 0°–35°N, the model was forced by the cross-calibrated multi-platform(CCMP) wind fi elds of September 15 to October 5, 2011. We then validated the simulation results against wave radar data observed from an oil platform and altimeter data from the Jason-2 satellite. The simulated waves were characterized by fi ve points along track using the Spectrum Integration Method(SIM) and the Spectrum Partitioning Method(SPM), by which wind sea and swell components of the 1D and 2D wave spectra are separated. There was reasonable agreement between the model results and observations, although the WW3 wave model may underestimate swell wave height. Signifi cant wave heights are large along the typhoon track and are noticeably greater on the right of the track than on the left. Swells from the east are largely unable to enter the South China Sea because of the obstruction due to the Philippine Islands. During the initial stage and later period of the typhoon, swells at the fi ve points were generated by the propagation of waves that were created by typhoons Haitang and Nalgae. Of the two methods, the 2D SPM method is more accurate than the 1D SIM which overestimates the separation frequency under low winds, but the SIM method is more convenient because it does not require wind speed and wave direction. When the typhoon left the area, the wind sea fractions decreased rapidly. Under similar wind conditions, the points located in the South China Sea are affected less than those points situated in the open sea because of the infl uence of the complex internal topography of the South China Sea. The results reveal the characteristic wind sea and swell features of the South China Sea and adjacent areas in response to typhoon Nesat, and provide a reference for swell forecasting and offshore structural designs.

Station Model for Rail Transit System Using Cellular Automata

In this paper, we propose a new cellular automata model to simulate the railway traffic at station. Based on NaSch model, the proposed station model is composed of the main track and the siding track. Two different schemes for trains passing through station are considered. One is the scheme of ＂pass by the main track, start and stop by the siding track＂. The other is the scheme of ＂two tracks play the same role＂. We simulate the train movement using the proposed model and analyze the traffic flow at station. The simulation results demonstrate that the proposed cellular automata model can be successfully used for the simulations of railway traffic. Some characteristic behaviors of railway traffic flow can be reproduced. Moreover, the simulation values of the minimum headway are close to the theoretical values. This result demonstrates the dependability and availability of the proposed model.

Ag-GST/HfO_(x)-based unidirectional threshold switching selector with low leakage current and threshold voltage distribution for high-density cross-point arrays

The use of electrochemical-metallization-based volatile threshold switching selectors in cross-point arrays has been widely explored owing to their high on-off ratios and simple structure.However,these devices are unsuitable for cross-point architectures because of the difficulty in controlling the random filament formation that results in large fluctuations in the threshold voltage during operation.In this study,we investigated the unidirectional threshold transition characteristics associated with an Ag/GST/HfO_(x)/Pt-based bilayer selector and demonstrated the occurrence of a low leakage current(<1×10^(-11) A) and low distribution of the threshold voltage(Δ0.11 V).The bilayer structure could control the filament formation in the intermediate state through the insertion of an HfO_(x) tunneling barrier.By stacking a bilayer selector with NiO_(x)based resistive random-access memory,the leakage and programming currents of the device could be significantly decreased.For the crossbar array configuration,we performed equivalent circuit analysis of a one-selector oneresistor(1S1R) devices and estimated the optimal array size to demonstrate the applicability of the proposed structure.The maximum acceptable crossbar array size of the 1S1R device with the Ag/GST/HfO_(x)/Pt/Ti/NiO_(x)/Pt structure was 5.29×10^(14)(N^(2),N=2.3×10^(7)).

Estimation of marine winds in and around typhoons using multi-platform satellite observations: Application to Typhoon Soulik (2018)

Estimating horizontal winds in and around typhoons is important for improved monitoring and prediction of typhoons and mitigating their damages.Here,we present a new algorithm for estimating typhoon winds using multiple satellite observations and its application to Typhoon Soulik(2018).Four kinds of satellite remote sensing data,along with their relationship to typhoon intensity,derived statistically from hundreds of historical typhoon cases,were merged into the final product of typhoon wind(MT wind):(1)geostationarysatellite-based infrared images(IR wind),(2)passive microwave sounder(MW wind),(3)feature-tracked atmospheric motion vectors,and (4)scatterometer-based sea surface winds(SSWs).The algorithm was applied to two cases(A and B)of Typhoon Soulik and validated against SSWs independently retrieved from active microwave synthetic aperture radar(SAR)and microwave radiometer(AMSR2)images,and vertical profiles of wind speed derived from reanalyzed data and dropsonde observations.For Case A(open ocean),the algorithm estimated the realistic maximum wind,radius of maximum wind,and radius of 15 m/s,which could not be estimated using the reanalysis data,demonstrating reasonable and practical estimates.However,for Case B(when the typhoon rapidly weakened just before making landfall in the Korean Peninsula),the algorithm significantly overestimated the parameters,primarily due to the overestimation of typhoon intensity.Our study highlights that realistic typhoon winds can be monitored continuously in real-time using multiple satellite observations,particularly when typhoon intensity is reasonably well predicted,providing timely analysis results and products of operational importance.

A pan-cancer integrative pathway analysis of multi-omics data

Background:Multi-view-omics datasets offer rich opportunities for integrative analysis across genomic,transcriptomic,and epigenetic data platforms.Statistical methods are needed to rigorously implement current research on functional biology,matching the complex dynamics of systems genomic datasets.Methods:We apply imputation for missing data and a structural,graph-theoretic pathway model to a dataset of 22 cancers across 173 signaling pathways.Our pathway model integrates multiple data platforms,and we test for differential activation between cancerous tumor and healthy tissue populations.Results:Our pathway analysis reveals significant disturbance in signaling pathways that are known to relate to oncogenesis.We identify several pathways that suggest new research directions,including the Trk signaling and focal adhesion kinase activation pathways in sarcoma.Conclusions:Our integrative analysis confirms contemporary research findings,which supports the validity of our findings.We implement an interactive data visualization for exploration of the pathway analyses,which is available online for public access.

A vertically integrated capacitorless memory cell

A two-port capacitorless PNPN device with high density,high speed and low power memory fabricated using standard CMOS technology is presented.Experiments and calibrated simulations were conducted which prove that this new memory cell has a high operation speed（ns level）,large read current margin（read current ratio of 10~4×）,low process variation,good thermal reliability and available retention time（190 ms）.Furthermore,the new memory cell is free of the cyclic endurance/reliability problems induced by hot-carrier injection due to the gateless structure.