An improved NDVI-based threshold method for estimating land surface emissivity using MODIS satellite data

This work estimated the land surface emissivities (LSEs) for MODIS thermal infrared channels 29 (8.4–8.7 μm), 31 (10.78–11.28 μm), and 32 (11.77–12.27 μm) using an improved normalized difference vegetation index (NDVI)-based threshold method. The channel LSEs are expressed as functions of atmospherically corrected reflectance from the MODIS visible and near-infrared channels with wavelengths ranging from 0.4 to 2.2 μm for bare soil. To retain the angular information, the vegetation LSEs were explicitly expressed in the NDVI function. The results exhibited a root mean square error (RMSE) among the estimated LSEs using the improved method, and those calculated using spectral data from Johns Hopkins University (JHU) are below 0.01 for channels 31 and 32. The MODIS land surface temperature/emissivity (LST/E) products, MOD11_L2 with LSE derived via the classification-based method with 1 km resolution and MOD11C1 with LSE retrieved via the day/night LST retrieval method at 0.05° resolution, were used to validate the proposed method. The resultant variances and entropies for the LSEs estimated using the proposed method were larger than those extracted from MOD11_L2, which indicates that the proposed method better described the spectral variation for different land covers. In addition, comparing the estimated LSEs to those from MOD11C1 yielded RMSEs of approximately 0.02 for the three channels; however, more than 70% of pixels exhibited LSE differences within 0.01 for channels 31 and 32, which indicates that the proposed method feasibly depicts LSE variation for different land covers.     

基于场景的车载设备测试用例自动生成方法研究

列控车载子系统是确保列车的安全运行的关键设备,对车载子系统进行测试是保证功能实现与系统规范一致性的重要手段。针对传统手工测试用例生成的效率低、耗时长、工作量繁杂、可重用性低等缺陷,提出一种基于场景的车载系统测试用例自动生成方法,依据CTCS-3级列控系统技术规范构造车载子系统场景树模型,由实时系统测试用例自动生成工具Co Ver对列车运行模式转换自动机网模型生成基于场景的测试用例,并由运行模式最小重复度选择算法生成全模式覆盖的测试序列。结论证明,基于场景自动生成的测试用例能够覆盖全部车载模式,并提高了模式转换测试序列生成效率。     

合成气甲烷化过程热力学分析

以化学热力学为基础,利用FactSage软件对2种典型的煤气化合成气甲烷化反应过程进行了热力学计算和分析。研究了合成气的组分、氢气的配比、反应温度、压力等条件对甲烷化过程的影响,特别是氢气的配比研究,区别于常规对H_2/CO分析而是以氢气的理论配比H_2/(3CO+4CO_2)进行分析。结果表明:反应器操作压力对甲烷化过程的影响不明显,合成气的组分、氢气的配比、反应温度的选择对甲烷化过程的影响较大。得出:合成气甲烷化过程应采用多段反应器,最终控制温度为(300~350)℃;操作压力一般为(3.0~3.5)MPa;H_2的配比采用理论配比时生产出的CH_4浓度高。     

An Improved Neural Network with Random Weights Using Backtracking Search Algorithm

This paper proposes a hybrid algorithm by combining backtracking search algorithm (BSA) and a neural network with random weights (NNRWs), called BSA-NNRWs-N. BSA is utilized to optimize the hidden layer parameters of the single layer feed-forward network (SLFN) and NNRWs is used to derive the output layer weights. In addition, to avoid over-fitting on the validation set, a new cost function is proposed to replace the root mean square error (RMSE). In the new cost function, a constraint is added by considering RMSE on both training and validation sets. Experiments on classification and regression data sets show promising performance of the proposed BSA-NNRWs-N.     

New quantum codes from dual-containing cyclic codes over finite rings

Let \(R=\mathbb {F}_{2^{m}}+u\mathbb {F}_{2^{m}}+\cdots +u^{k}\mathbb {F}_{2^{m}}\), where \(\mathbb {F}_{2^{m}}\) is the finite field with \(2^{m}\) elements, m is a positive integer, and u is an indeterminate with \(u^{k+1}=0.\) In this paper, we propose the constructions of two new families of quantum codes obtained from dual-containing cyclic codes of odd length over R. A new Gray map over R is defined, and a sufficient and necessary condition for the existence of dual-containing cyclic codes over R is given. A new family of \(2^{m}\)-ary quantum codes is obtained via the Gray map and the Calderbank–Shor–Steane construction from dual-containing cyclic codes over R. In particular, a new family of binary quantum codes is obtained via the Gray map, the trace map and the Calderbank–Shor–Steane construction from dual-containing cyclic codes over R.     

A modular designed bolt tightening shaft based on adaptive fuzzy backstepping control

This paper presents a modular designed autonomous bolt tightening shaft system with an adaptive fuzzy backstepping control approach developed for it. The bolt tightening shaft is designed for the autonomous bolt tightening operation, which has huge potential for industry application. Due to the inherent nonlinear and uncertain properties, the bolt tightening shaft and the bolt tightening process are mathematically modeled as an uncertain strict feedback system. With the adaptive backstepping and approximation property of fuzzy logic system, the controller is recursively designed. Based on the Lyapunov stability theorem, all signals in the closed-loop system are proved to be uniformly ultimately bounded and the torque tracking error exponentially converges to a small residue. And the effectiveness and performance of the proposed autonomous system are verified by the simulation and experiment results on the bolt tightening shaft system.     

图谱法脑部MRI图像自动分割技术发展及应用

脑部MRI图像自动分割是计算机技术运用于医学上的一个典 型工作,脑部图像分割技术对于人类研究脑部疾病具有重要意义。虽然有一些非常广泛应用 的图像分割方法,如阈值法、区域增长法、聚类法等,但在脑部MRI图像分割中,这些方法 都 没有图谱法具有更为实际的医学研究与临床价值。本文回顾了脑部图像配准、分割的发展历 程,介绍了图谱分割算法的发展及基本原理,以及当前比较前沿的多图谱分割系统的组成和 应用。最后本文对图谱法脑部自动分割在实际临床医学中的应用前景作了总结和展望。     

未来大数据环境下的配用电通信网虚拟网络架构及应用

根据智能配电网的通信需求,本文提出了基于无线 Mesh 网和电力线通信网的智能配电网通信框架。在此框架的基础上,设计了一个遗传算法和启发式算法,为不同类型的业务分别建立虚拟网络并将其映射到异构的物理网络中,通过增加传输分集来保证实时业务的可靠性。通过仿真,验证两种映射算法在保证实时业务可靠性的基础上,使尽力而为型业务的吞吐率达到最大化。