Robust Blind Separation for MIMO Systems against Channel Mismatch Using Second-Order Cone Programming

To improve the deteriorated capacity gain and source recovery performance due to channel mismatch problem,this paper reports a research about blind separation method against channel mismatch in multiple-input multiple-output(MIMO) systems.The channel mismatch problem can be described as a channel with bounded fluctuant errors due to channel distortion or channel estimation errors.The problem of blind signal separation/extraction with channel mismatch is formulated as a cost function of blind source separation(BSS) subject to the second-order cone constraint,which can be called as second-order cone programing optimization problem.Then the resulting cost function is solved by approximate negentropy maximization using quasi-Newton iterative methods for blind separation/extraction source signals.Theoretical analysis demonstrates that the proposed algorithm has low computational complexity and improved performance advantages.Simulation results verify that the capacity gain and bit error rate(BER) performance of the proposed blind separation method is superior to those of the existing methods in MIMO systems with channel mismatch problem.

An expert system for predicting shear stress distribution in circular open channels using gene expression programming

The shear stress distribution in circular channels was modeled in this study using gene expression programming(GEP). 173 sets of reliable data were collected under four flow conditions for use in the training and testing stages. The effect of input variables on GEP modeling was studied and 15 different GEP models with individual, binary, ternary, and quaternary input combinations were investigated. The sensitivity analysis results demonstrate that dimensionless parameter y/P, where y is the transverse coordinate, and P is the wetted perimeter, is the most influential parameter with regard to the shear stress distribution in circular channels. GEP model 10, with the parameter y/P and Reynolds number(Re) as inputs, outperformed the other GEP models, with a coefficient of determination of 0.7814 for the testing data set. An equation was derived from the best GEP model and its results were compared with an artificial neural network(ANN) model and an equation based on the Shannon entropy proposed by other researchers. The GEP model, with an average RMSE of 0.0301, exhibits superior performance over the Shannon entropy-based equation, with an average RMSE of 0.1049, and the ANN model, with an average RMSE of 0.2815 for all flow depths.

Robust MIMO Precoding for Cognitive Multiuser Relay Networks with Imperfect Channel State Information

In this paper, a novel robust precoder with imperfect channel state information(CSI)is proposed for multi-input multi-output(MIMO)cognitive multiuser networks equipped with relays. In the proposed model, the secondary users(SUs)are allowed to share the spectrum with the primary users(PUs)when the interference temperature(IT)is below a specific threshold. The transmitting strategy of relays is amplify-and-forward(AF), and the CSI error is characterized in terms of spherical uncertainty region. A minmax problem for the transmit power of the relays is considered when the mean square error(MSE)of SUs and the IT of PU meet their corresponding thresholds, and it is transformed into a semi-definite programming(SDP)problem to search for the solution. Numerical simulations demonstrate the effectiveness of the proposed precoder.

A Bilevel Programming Approach for Optimization of Airport Ground Movement

This paper proposes an optimization model for the airport ground movement problem(GMP)based on bilevel programming to address taxi conflicts on the airport ground and to improve the operating safety and efficiency.To solve GMP,an iterative heuristic algorithm is designed.Instead of separately investigating each problem,this model simultaneously coordinates and optimizes the aircraft routing and scheduling.A simulation test is conducted on Nanjing Lukou International Airport(NKG)and the results show that the bilevel programming model can clearly outperform the widely used first-come-first-service(FCFS)scheduling scheme in terms of aircraft operational time under the precondition of none conflict.The research effort demonstrates that with the reduced operating cost and the improved overall efficiency,the proposed model can assist operations of the airports that are facing increasing traffic demand and working at almost maximum capacity.

Hierarchical adaptive stereo matching algorithm for obstacle detection with dynamic programming

An adaptive weighted stereo matching algorithm with multilevel and bidirectional dynamic programming based on ground control points （GCPs） is presented. To decrease time complexity without losing matching precision, using a multilevel search scheme, the coarse matching is processed in typical disparity space image, while the fine matching is processed in disparity-offset space image. In the upper level, GCPs are obtained by enhanced volumetric iterative algorithm enforcing the mutual constraint and the threshold constraint. Under the supervision of the highly reliable GCPs, bidirectional dynamic programming framework is employed to solve the inconsistency in the optimization path. In the lower level, to reduce running time, disparity-offset space is proposed to efficiently achieve the dense disparity image. In addition, an adaptive dual support-weight strategy is presented to aggregate matching cost, which considers photometric and geometric information. Further, post-processing algorithm can ameliorate disparity results in areas with depth discontinuities and related by occlusions using dual threshold algorithm, where missing stereo information is substituted from surrounding regions. To demonstrate the effectiveness of the algorithm, we present the two groups of experimental results for four widely used standard stereo data sets, including discussion on performance and comparison with other methods, which show that the algorithm has not only a fast speed, but also significantly improves the efficiency of holistic optimization.

Automatic Analysis Reporting for Hydro-Chemical Data Using Updated DurovPwin Program

Graphical representation of groundwater major dissolved constituents greatly help researchers in understanding the hydro-chemical evolution, grouping and areal distribution. Durov diagram is one of the most widely used technique but it requires a lot of tedious calculations. The DurovPlot program, which is used to plot the expanded Durov diagram as a graphical representation of groundwater major dissolved constituents is working on Disk Operating System （DOS） environment. Therefore, the need of a new program working under windows is a must. The program termed as DurovPwinis developed using Microsoft visual studio 2010. The DurovPwin program not only calculates the Durov coordinates and plot it, but also plots the total dissolved solids （TDS） on logarithmic scale and the measure of the activity of hydrogen ion （pH） of the given samples. The updated DurovPwin adds many features such as interface with Microsoft Office package （Word and Excel） to read the input chemical elements and automatically write result interpretation report. The user facility to group wells based on data features is added and the selection of the electric balance tolerance （10% as default） value is given. Another feature of the modified DurovPwinis has the ability to do useful X-Y plot for different hydro-chemical parameters to assist in data interpretation. The sodium adsorption ratio （SAR） is also calculated and written in the final report. Also, in the present study, the usability of the new version of DurovPwin program has been tested on the chemical data from 59 groundwater samples collected from A1-Jawf area, Saudi Arabia. The collected water samples were mainly from the Secondary-Tertiary-Quaternary （STQ） aquifer and some from Tawil and Jaufaquifers. The grouping of the major ions in the three aquifers have been displayed and presented using the DurovPwin program. The TDS values of Tawil aquifer ranges from 257.9 to 822.3 （2.4115 to 2.915） and for Jawf aquifer from 494.4 to 1,070 （2.6941 to 3.0294） and for STQ aquifer ranges from 399.5 to 9,861.8 （2.6015 to 3.994）. The pH for the three aquifers ranges from 7 to 7.9, 7.6 to 7.8 and 7.2 to 8.3, respectively.

Progress of International Meridian Circle Program

Based on the Chinese Meridian Project(CMP),the International Meridian Circle Program(IMCP)aims to coordinate the deployment of a comprehensive ground-based monitoring network along the 120°E-60°W Great Meridian Circle to track the propagation and evolution of space weather events from the Sun to the Earth,as well as the imprints of other major natural and anthropic hazards on the ionosphere,the middle and upper atmosphere.Currently,we have completed the IMCP headquarters building in Beijing and established the China-Brazil Joint Laboratory for Space Weather in cooperation with Brazil.Meanwhile,the Chinese Meridian Project PhaseⅡand different components of the IMCP observation system are under construction.

Case studies of earthquake-induced effects on concrete channels

Case studies are presented for two concrete lined channels shaken by strong ground motions during the 1994 Northridge earthquake, the high speed channel （HSC） and bypass channel （BC）, on the Los Angeles Department of Water and Power＇s Van Norman Complex. Performances of these two channels as they pass through different subsurface materials identify several important seismic aspects and the critical role of geotechnical earthquake engineering in assessing channel behaviors. Preliminary evaluations using detailed mapping of channel cracks, permanent ground movements, subsurface profiles, and nearby strong ground motion recordings from the 1994 earthquake show that the channel liners may have been damaged from both transient motions and permanent ground movements. Damage from permanent ground deformations is obvious by observation; therefore simplified analyses are presented only for transient movements. Site specific transient response analyses are performed to provide an initial assessment of the differing effects from transient and permanent ground movements on HSC and BC liner damage. These case studies are helpful for introducing the potential for lifeline damage from transient movements within zones of permanent ground movement, a concept not well understood in the earthquake engineering community

On Transit Gait Programming of Six-legged Wall-climbing Robot

Transit gait programming is a key problem for a multi-legged robot to climb automatically from the ground up the wall, as well as between wall intersections. In this paper, a new idea is put forward by which the complex transit gait is decomposed into a sequence of two relatively simpler parts - single-leg motion and body pitching motion. An algorithm based on the above concept shows its feasibility and effectiveness in the graphic kinematics simulation.

Genetic programming for predictions of effectiveness of rolling dynamic compaction with dynamic cone penetrometer test results

Rolling dynamic compaction (RDC),which employs non-circular module towed behind a tractor,is an innovative soil compaction method that has proven to be successful in many ground improvement applications.RDC involves repeatedly delivering high-energy impact blows onto the ground surface,which improves soil density and thus soil strength and stiffness.However,there exists a lack of methods to predict the effectiveness of RDC in different ground conditions,which has become a major obstacle to its adoption.For this,in this context,a prediction model is developed based on linear genetic programming (LGP),which is one of the common approaches in application of artificial intelligence for nonlinear forecasting.The model is based on in situ density-related data in terms of dynamic cone penetrometer (DCP) results obtained from several projects that have employed the 4-sided,8-t impact roller (BH-1300).It is shown that the model is accurate and reliable over a range of soil types.Furthermore,a series of parametric studies confirms its robustness in generalizing data.In addition,the results of the comparative study indicate that the optimal LGP model has a better predictive performance than the existing artificial neural network (ANN) model developed earlier by the authors.

The regulatory and modulatory roles of TRP family channels in malignant tumors and relevant therapeutic strategies

Transient receptor potential(TRP)channels are one primary type of calcium(Ca^(2+))permeable channels,and those relevant transmembrane and intracellular TRP channels were previously thought to be mainly associated with the regulation of cardiovascular and neuronal systems.Nowadays,however,accumulating evidence shows that those TRP channels are also responsible for tumorigenesis and progression,inducing tumor invasion and metastasis.However,the overall underlying mechanisms and possible signaling transduction pathways that TRP channels in malignant tumors might still remain elusive.Therefore,in this review,we focus on the linkage between TRP channels and the significant characteristics of tumors such as multi-drug resistance(MDR),metastasis,apoptosis,proliferation,immune surveillance evasion,and the alterations of relevant tumor micro-environment.Moreover,we also have discussed the expression of relevant TRP channels in various forms of cancer and the relevant inhibitors’efficacy.The chemo-sensitivity of the anti-cancer drugs of various acting mechanisms and the potential clinical applications are also presented.Furthermore,it would be enlightening to provide possible novel therapeutic approaches to counteract malignant tumors regarding the intervention of calcium channels of this type.

Enhancement of Soil Discharge Channels on Potential Surrounding Buried Cables Under Impulsive Currents

Substations have a large number of signal transmission cables beneath the ground.Both the insulation safety and signal reliability of the cables are affected severely by the electromagnetic field.Under high-amplitude impulsive currents,the dispersion of currents can cause soil discharge and thus cause unexpected distortions in an electromagnetic field.This paper focuses on the distortions of the electric field.In general,soil discharge channels occur in the vicinity of the independent rod.Closer development of the channel might enhance the electric field distribution and the potential surrounding the outer insulation of the cables(i.e.the surface potential on the cable).Therefore,this paper establishes a platform for observing the soil discharge channel and measuring the surface potential.Direction characteristic of the channel is extracted from the captured image of soil discharge channels and the surface potential is obtained by the measured coupling capacitive current on the shield experimentally.This paper also presents an improved model considering a dynamic growing discharge channel for the transient analysis of the grounding electrode.Study results show the surface potential increases as the discharge channel approaches the cable.To quantify this enhancement effect,the ratio of the highest to the lowest value of surface potential in different directions is taken as the multiple of the surface potential increase.The calculated multiples of the surface potential increase are in the range of 1 to 1.64 times under different conditions by the improved model.Therefore,taking the soil discharge channel into account is helpful to accurately analyze the impulsive interference of buried cables.

Innovation Renaissance China has pledged to channel its efforts into breaking new ground in science and technology in the coming years

As 2006 unfolds, China plans to transform its economic development mode to usher in a new era of innovation. The National Conference on Science and Technology, held this month, provides a fresh impetus to that endeavor. The strategy of "enhancing

企业如何通过数字化转型实现颠覆性创新?——基于潍柴集团的案例研究

数字经济时代促使企业进入数字化转型过程中,企业数字化转型离不开数字技术的发展与数字产物的嵌入,在二者的催化下多端颠覆性创新成为企业转型新常态,而数字化转型如何赋能制造业企业颠覆性创新形成数字化颠覆性创新以把握数字时代契机,打造企业新型竞争优势是可拓展的研究问题。本文以潍柴集团为例,依托于颠覆性创新理论,通过程序化扎根理论分析对象,对制造业企业实现数字化颠覆性创新的过程机制以及形成路径进行探究。研究发现,企业进行数字化颠覆性创新要经历驱动、转型以及多元三个阶段。驱动阶段,企业受内外驱动因素影响,启动数字化颠覆性创新;转型阶段,企业以生产模式转变与组织结构演化为行动路径,通过对企业内外的数字化实现企业的数字化颠覆性创新;多元阶段,通过实现商业生态系统的数字化颠覆性创新进行创新外延,形成数字商业生态系统模式,完成颠覆性创新转型。

多源遥感卫星地面调度系统设计与实现

针对卫星地面调度处理系统进行研究与设计,着重关注工作流、线程池和Redis缓存等关键技术。首先,对工作流的分析和建模以提高系统任务的执行效率和资源利用率。其次,引入线程池技术来管理和调度系统中的线程资源,实现任务的并发执行和负载均衡,提高系统的吞吐量和响应速度。最后,利用Redis缓存作为系统的缓存和Kafka消息队列,优化数据存取和通信效率,提供更高的性能和可靠性。整体通过SpringBoot框架进行实验和性能评估,验证了该系统在任务处理能力、资源利用率和数据访问效率等方面的优势。本研究对于提高卫星地面调度处理系统的效率和性能具有一定的实践意义和推广价值。

Stochastic Air Traffic Flow Management for Demand and Capacity Balancing Under Capacity Uncertainty

This paper introduces an innovative approach to the synchronized demand-capacity balance with special focus on sector capacity uncertainty within a centrally controlled collaborative air traffic flow management(ATFM)framework.Further with previous study,the uncertainty in capacity is considered as a non-negligible issue regarding multiple reasons,like the impact of weather,the strike of air traffic controllers(ATCOs),the military use of airspace and the spatiotemporal distribution of nonscheduled flights,etc.These recessive factors affect the outcome of traffic flow optimization.In this research,the focus is placed on the impact of sector capacity uncertainty on demand and capacity balancing(DCB)optimization and ATFM,and multiple options,such as delay assignment and rerouting,are intended for regulating the traffic flow.A scenario optimization method for sector capacity in the presence of uncertainties is used to find the approximately optimal solution.The results show that the proposed approach can achieve better demand and capacity balancing and determine perfect integer solutions to ATFM problems,solving large-scale instances(24 h on seven capacity scenarios,with 6255 flights and 8949 trajectories)in 5-15 min.To the best of our knowledge,our experiment is the first to tackle large-scale instances of stochastic ATFM problems within the collaborative ATFM framework.

中国特色教育技术学基础理论研究框架与运用示例--基于教育哲学和程序化扎根理论

基础理论研究是任何学科发展的命脉是学科之基。然而,在教育数字化转型和当前主流教育实证研究范式下,我国教育技术学对本土化的基础理论研究的关注度还远不够。基础理论是我国教育技术学的根本,建构中国特色教育技术学基础理论体系尤为重要。当前,中国特色教育技术学基础理论体系尚未形成很大原因是缺少方法论指导。基于此,文章从方法论的层面探讨如何开展中国特色教育技术学基础理论研究框架,首先,从教育哲学视角对基础理论体系分类;其次,基于教育哲学的运思方式和程序化扎根理论方法,建构基础理论的研究范畴;最后,举例说明如何利用该框架开展中国特色教育技术学基础理论的研究,以期为我国教育技术学基础理论研究工作尽绵薄之力。

无人机毫米波通信信道带宽估计研究

由于毫米波频段的可用频谱资源相对较窄,频谱拥挤会导致无人机(UAV)通信中断,且信道带宽估值过大或过小都不利于无人机毫米波通信的实施。为了顺利实施无人机毫米波通信,提出无人机毫米波通信信道带宽估计方法。在无人机控制器中设置可编程门阵列(FPGA)缓存模块,根据通信容量使用混合编帧处理毫米波通信数据。选择动态通信节点,根据数据覆盖率设计无人机通信编码方案。利用通信导频插入条件,获取自适应通信阶数,定义正则化估计参数,实现对信道带宽的估计。测试结果表明,所提方法下的毫米波通信更加稳定,且带宽数值保持在5×10^(11)Mibit以下,信道带宽估值与真实信道带宽占用量之间的差值始终未超过1.0×10^(11)Mibit,有利于保障无人机毫米波通信的顺利实施。

融合卫星姿态的星地信道建模及硬件模拟

针对传统星地信道模型及其硬件模拟方法没有考虑卫星姿态对信道特性影响的问题,本文基于几何地理随机模型(Geometry-based Stochastic Model,GBSM)框架,提出了一种融合卫星姿态的星地信道模型。该模型通过构建四个独立的坐标系并引入姿态修正矩阵,来描述卫星姿态变化对星地信道特性造成的影响。在此基础上,本文基于现场可编程门阵列(Field Programmable Gate Array,FPGA),设计并研制了一种星地信道硬件模拟器。硬件模拟器采用差分迭代的算法来生成信道衰落因子,可以极大提高硬件模拟的实时性,确保生成的衰落数据与实际场景相匹配。同时,还采用了并行处理架构,可以支持最大640 MHz带宽的星地信道模拟。为了将衰落数据与并行架构相匹配,引入了并行内插算法,可以将串行的衰落数据内插成同速率的多路并行衰落数据。此外,为了能够精准控制硬件装置输出信号的功率,设计了基于预训练的功率校正方法。通过内部校正源信号预先训练出整个模拟过程给信号带来的增益再进行功率补偿,从而保证输出信号的功率可以被精准控制。最后,在典型场景下开展仿真模拟,导出硬件模拟器的输出结果并分析其统计特性,结果表明实测输出的概率密度函数(Probability Density Function,PDF)和多普勒功率谱密度(Doppler Power Spectral Density,DPSD)与理论值吻合,证明本文设计的硬件模拟器可以准确地复现实际场景下卫星姿态发生变化的星地信道。本文提出的融合卫星姿态的星地信道模型以及研制的硬件模拟器很好地解决了传统模型以及硬件模拟方法的局限性,在卫星通信系统的优化、评估和验证环节具有极大的潜在价值。

MIMO探地雷达随机步进频信号旁瓣抑制

针对MIMO探地雷达中随机步进频信号的距离旁瓣较高的问题,提出了一种基于快速二阶锥优化问题的旁瓣抑制方法。该方法首先通过建立随机步进频信号模型对回波信号进行预处理,然后基于回波信号的旁瓣特点将旁瓣抑制问题转化为以信号的峰值旁瓣构建目标函数,以主峰损失、峰值旁瓣和积分旁瓣联合约束的二阶锥优化问题,最后使用内点法求解二阶锥规划问题,以此得到最优的旁瓣滤波器系数。仿真和实测数据处理结果表明,设计的失配滤波器能够在较低主峰损耗的情况下,有效降低峰值旁瓣电平和积分旁瓣电平,提高信号的主旁瓣比。该方法为MIMO探地雷达中的距离旁瓣问题提供了有效解决思路,有望在工程应用中提高探地雷达的性能。