岩土中结构表面刚性压力传感器动匹配问题的数值计算研究

有限元计算结果表明：在升压时间大于０．３ｍｓ的动荷载作用下，结构表面刚性压力传感器动匹配误差与静匹配误差一样，都近似为零，可不考虑匹配问题的影响。

基于Frenet坐标系的道岔区侧向轨道几何状态动静态检测匹配方法

针对道岔区侧向轨道几何状态动态检测的现场病害定位难度大的问题,基于Frenet坐标系和笛卡尔坐标系的映射关系,将道岔区轨道几何状态静态检测的空间点坐标转化为动态检测的空间曲线,并采用线性相位有限冲激响应(Finite Impulse Response,FIR)数字高通滤波器进行空间滤波,获得与动态轨道几何不平顺相同波长范围的轨向及高低,实现动静态检测的匹配。与静态检测传统弦测输出不同,该匹配方法不会导致轨道几何不平顺幅值发生畸变,借助静态检测的空间定位数据,横向对比动态检测输出,可快速完成道岔区侧向病害定位,对道岔区现场养护维修具有指导意义。

眼动轨迹匹配法:一种研究决策过程的新方法

眼动轨迹匹配法是近年来新兴的一种眼动数据分析方法,该方法包括注视数据的预处理、兴趣区划分和编码、形成眼动轨迹字符串、计算相似性得分四个步骤。研究者采用眼动轨迹匹配法对决策过程理论及其影响因素进行的探索性研究,证实了眼动轨迹匹配法在决策领域的可行性、精确性和高价值性。未来的研究应进一步利用眼动轨迹匹配法加强对各种决策理论及其影响因素的研究,以揭示决策的认知过程,构建更加完善的决策理论模型。

某轻卡动转系统匹配与转向直拉杆设计

文章对某轻型卡车动转系统匹配与转向直拉杆设计过程进行了详细阐述,包括动转泵与转向器的压力、流量进行匹配计算;运用三维数模对直拉杆进行外形设计及空间干涉校核,对转向直拉杆的强度进行计算分析,对转向系与悬架系的运动干涉进行校核,最终使动转系统匹配及直拉杆设计满足整车开发需求。

基于摄动能量匹配条件的椭圆参考轨道伴飞构型设计

针对J2摄动下椭圆参考轨道的稳定伴飞问题,提出了J2摄动下的能量匹配条件,给出了迹向相对速度和径向相对位置的迭代设计方法,并设计了一种新的椭圆参考轨道伴飞构型.在此基础上,利用J2摄动下的能量匹配条件给出了计算伴飞初始相对状态的方法,并基于拉格朗日乘子法给出了位置保持脉冲的解析表达式,以获得形成稳定伴飞的初始相对状态和位置保持脉冲.仿真表明满足摄动能量匹配条件能形成稳定的伴飞构型,采用新的伴飞构型及其设计方法能明显减小分离距离的设计偏差.

GPS probe map matching algorithm based on spatial data model

To improve the performance of the traditional map matching algorithms in freeway traffic state monitoring systems using the low logging frequency GPS （global positioning system） probe data, a map matching algorithm based on the Oracle spatial data model is proposed. The algorithm uses the Oracle road network data model to analyze the spatial relationships between massive GPS positioning points and freeway networks, builds an N-shortest path algorithm to find reasonable candidate routes between GPS positioning points efficiently, and uses the fuzzy logic inference system to determine the final matched traveling route. According to the implementation with field data from Los Angeles, the computation speed of the algorithm is about 135 GPS positioning points per second and the accuracy is 98.9%. The results demonstrate the effectiveness and accuracy of the proposed algorithm for mapping massive GPS positioning data onto freeway networks with complex geometric characteristics.

Resource allocation based on fairness and QoS provisioning for OFDMA-WLAN system

To satisfy different service requirements of multiple users in the orthogo nal frequency division multiple access wireless local area network OFDMA-WLAN system downlink transmission a resource allocation algorithm based on fairness and quality of service QoS provisioning is proposed. Different QoS requirements are converted into different rate requirements to calculate the QoSs atisfaction level.The optimization object is revised as a fairness-driven resource optimization function to provide fairness. The complex resource allocation problem is divided into channel allocation and power assignment sub-problems. The sub-problems are solved by the bipartite graph matching and water-filling based method.Compared with other algorithms the proposed algorithm sacrifices less data rate for higher fairnes and QoS satisfaction.The sim ulation results show that the proposed algorithm is capableo fp rovi ding QoS and fairness and performs better in a tradeoff among QoS fairness and data rate.

Feature Relationship and Process Planning

Concurrent engineering(CE)involves the consideration during the design phase of the various factors associated with the life cycle of the product.Using the principle of CE,a feature-based CAPP system is proposed.On the basis of feature modeling,the system is able to reason feature relationships,produce feature digraph of a part,and decide the machining sequence of features.

Cycle life prediction and match detection in retired electric vehicle batteries

The lifespan models of commercial 18650-type lithium ion batteries （nominal capacity of 1150 mA-h） were presented. The lifespan was extrapolated based on this model. The results indicate that the relationship of capacity retention and cycle number can be expressed by Gaussian function. The selecting function and optimal precision were verified through actual match detection and a range of alternating current impedance testing. The cycle life model with high precision （〉99%） is beneficial to shortening the orediction time and cutting the prediction cost.

Parameters matching and optimization of parallel hybrid electric vehicle powertrain

Aiming at the development of parallel hybrid electric vehicle （PHEV） powertrain, parameter matching and optimization are presented, According to the performance of PHEV, the optimization range of engine, motor, driveline gear ratio and battery parameters are determined. And then a two-level optimization problem is formulated based on analytical target cascading （ATC）. At the system level, the optimization of the whole vehicle fuel economy is carried out, while the tractive performance is defined as the constraints. The optimized parameters are cascaded to the subsystem as the optimization targets. At the subsystem level, the final drive and transmission design are optimized to make the ratios as close to the targets as possible. The optimization result shows that the fuel economy had improved significantly, while the tractive performance maintains the former level.

A fast block-matching algorithm based on variable shape search

Block-matching motion estimation plays an important role in video coding. The simple and efficient fast block-matching algorithm using Variable Shape Search (VSS) proposed in this paper is based on diamond search and hexagon search. The initial big diamond search is designed to fit the directional centre-biased characteristics of the real-world video se- quence, and the directional hexagon search is designed to identify a small region where the best motion vector is expected to locate. Finally, the small diamond search is used to select the best motion vector in the located small region. Experimental results showed that the proposed VSS algorithm can significantly reduce the computational complexity, and provide competitive computational speedup with similar distortion performance as compared with the popular Diamond-based Search (DS) algorithm in the MPEG-4 Simple Profile.

Novel Design for High Speed and Resolution Delta-sigma A/D Converter

The delta-sigma converter is one of the high speed and resolution analog-to-digital modulators. Its implementation needs the low oversampling technique and the multi-bit D/A converter. The noise induced by the multi-bit D/A converter becomes one of the key factors deteriorating the signal-to-noise rate of the delta-sigma A/D converter. A novel structure with signal unity transfunction, dynamic element matching(DEM) and noise-shaping is discussed. The method is investigated to design converter based on the proposed structure. The behavior simulation indicates that the structure and the design method are feasible.

Scan matching using line segment relationships for map-based localization of mobile robot

A new scan matching method for mobile robot localization is presented, which takes line segment as the feature and matches the real scans in the given reference map by relationships of the directional-defined line segments. The alignment was done by hierarchically identifying the multiple relationships and the result was recorded in a correspondence matrix, where the best match is defined and selected for localization. It is indicated that the searching algorithm of the best match can find the ambiguities and get rid of them. This method with less computational cost works well in occluded environment, and can correct the error in pose estimation without the need for the estimation itself. The efficiency, accuracy and robustness of this method were verified by experiments of localization in an occluded environment and a long-distance indoor navigation.

Single-territory incomplete surgical revascularization improves regional wall motion of remote ventricular areas： results from a propensity-matched study

Objective Basic science studies demonstrated a general intramyocardial angiogenetic response potentially responsible for the creation of a microvascular neocapillaries network assisting myocardial function. We hypothesized that the benefit provided by the reperfusion of left anterior descending （LAD） territories and the biological angiogenetic drive triggered by the revascularization could translate in a global improvement in ventricular contractility, not restricted to the grafted area. Methods High-risk patients with multivessel coronary artery disease and preoperative wall motion abnormalities were retrospectively analyzed to compare outcomes and regional ventricular function of those who received optimal medical therapy （OMT） versus those who underwent off-pump coronary artery bypass grafting （OPCABG） and received an incomplete myocardial revascularization using left internal mammary artery （LIMA） on LAD （OPCABG group）. From January 2007 to December 2014, 206 patients （OMT, n = 136, OPCABG, n = 70） were propensity-score matched to have 70 matched pairs. Variables included in propensity score analyses were ejection fraction （EF）, left ventricular end diastolic volume （LVEDVi）, EuroSCORE II. Primary endpoint was the variation in the global wall motion score index （AWMSI） as evaluated by transthoracic echocardiography. Follow up was completed at 3 years from surgery or hospital discharge. Results Regional analysis of ventricular function revealed a regional WMSI improvement in the OPCABG group not only for LAD territories but also for non-LAD regions, associated with a reduction in the negative left ventricular ischemic remodeling, compared to patients discharged in optimal medical therapy. Global AWMSI was negative in OPCABG group （-3.4 ± 2.8%） and positive in the OMT group （5.9 ± 3.1%）, indicating a better wall motion score for OPCAB patients. Surprisingly, regional WMSI improved also in non-grafted territories in the off-pump CABG group with a delta value of -3.7 ± 5.3% for left circumflex artery （LCX） area and -3.5 ± 5.4% for right coronary artery （RCA） area. Conclusions In patients with multivessel coronary artery disease, LIMA-to-LAD grafting is associated with an improvement in the WMSI involving also the surrounding non-LAD ungrafted segments and with the attenuation of negative global and regional ischemic ventricular remodeling.

3D Motion Parameters Determination Based on Binocular Sequence Images

Exactly capturing three dimensional (3D) motion i nf ormation of an object is an essential and important task in computer vision, and is also one of the most difficult problems. In this paper, a binocular vision s ystem and a method for determining 3D motion parameters of an object from binocu lar sequence images are introduced. The main steps include camera calibration, t he matching of motion and stereo images, 3D feature point correspondences and re solving the motion parameters. Finally, the experimental results of acquiring th e motion parameters of the objects with uniform velocity and acceleration in the straight line based on the real binocular sequence images by the mentioned meth od are presented.

Comparison of in-hospital outcomes between octogenarians and nonagenarians undergoing transcatheter aortic valve replacement： a propensity matched analysis

Background Aortic valve stenosis （AS） is very common in the elderly patients above 80 years. Transcatheter aortic valve replacement （TAVR） in such patients is being increasingly performed. This study sought to assess in-hospital outcome differences between octogenarians and nonagenarians and predictors of mortality in nonagenarians undergoing TAVR with severe AS. Method The study population was derived from the National Inpatient Sample （MS） for the years 2012-2014 using ICD-9 CM procedure codes 35.05 and 35.06 for TAVR. Hospitalizations below 80 years of age were excluded. After performing propensity score matching （1： 2）, in-hospital outcomes were compared in matched cohorts. Then, multivariate model was developed to analyze predictors of in-hospital mortality in nonagenarians. Results There were 11,630 hospitalizations in the octogenarian and 5815 hospitalizations in the nonagenarian group. Primary outcome of in-hospital mortality （6% vs. 4.1%, P ≤ 0.001） was higher in nonagenarians compared to octogenarians. Secondary outcomes including stroke （3.4% vs. 2.8%, P ≤ 0.001）, renal failure （18.9% vs. 17.3%, P ≤0.001）, blood transfusion （35% vs. 32.6%, P ≤ 0.001）, vascular complications （4.5% vs. 3.5%, P ≤ 0.001）, and pacemaker implantation （27.8% vs. 24.8%, P ≤ 0.001） were higher in nonagenarians. There was no difference in their length of stay. Median cost （70,3745 vs. 65,3815, P ≤ 0.001） was slightly higher with nonagenarian. Conclusions Although in-hospital mortality is slightly higher in nonagenarians, it is acceptable. This difference in mortality is at least partly explained by higher complications in nonagenarians. Efforts should be made to decrease the complications which can further narrow the difference in in-hospital mortality between the groups.

Matching between mechanics and thermodynamics among 4 individual strokes in a 4-stroke engine by non-circular gear mechanism

The relationship between engine mechanics and thermo-dynamics has been investigated by means of numerical simulation.The inherent mismatching between the mechanical behaviors and the thermodynamic process in internal combustion engine is identified,which is believed to be one of the important limiting factors of energy efficiency for conventional engines available in the current market.An approach for engine efficiency improvement through optimal matching between mechanics and thermodynamics(OMBMT)is proposed.An ideal matching model is defined and the conflicts due to the constraints among the mapping strokes in a 4-stroke engine are analyzed.A novel mechanical model is built for approaching optimal matching among all 4 individual strokes in a 4-stroke spark-ignition engine,which is composed of non-circular gears(NCG)and integrated with conventional slider crank engine mechanism.By means of digital mechanical model and numerical simulation,the matching gains among all 4 strokes are defined and calculated for quantifying the NCG engine efficiency improvement by comparing with a baseline engine.The potentials with the OMBMT implemented and the enhancements made by NCG mechanism for engines in terms of overall engine efficiency are reported.Based on the results achieved,it is recommended that the feasibility studies and the experimental validations should be conducted to verify the engine matching concept and effectiveness of the NCG mechanism engine model proposed,and the engine performance and NCG design parameters should be further optimized.

Optimizing of large-number-patterns string matching algorithms based on definite-state automata

Because the small CACHE size of computers, the scanning speed of DFA based multi-pattern string-matching algorithms slows down rapidly especially when the number of patterns is very large. For solving such problems, we cut down the scanning time of those algorithms (i.e. DFA based) by rearranging the states table and shrinking the DFA alphabet size. Both the methods can decrease the probability of large-scale random memory accessing and increase the probability of continuously memory accessing. Then the hitting rate of the CACHE is increased and the searching time of on the DFA is reduced. Shrinking the alphabet size of the DFA also reduces the storage complication. The AC++algorithm, by optimizing the Aho-Corasick (i.e. AC) algorithm using such methods, proves the theoretical analysis. And the experimentation results show that the scanning time of AC++and the storage occupied is better than that of AC in most cases and the result is much attractive when the number of patterns is very large. Because DFA is a widely used base algorithm in may string matching algorithms, such as DAWG, SBOM etc., the optimizing method discussed is significant in practice.

A Stoppable Clock Based Four Step Search Block-Matching Motion Estimation Architecture

Motion Estimation （ME） is considerate one of the most important compression methods. However, ME involves high computational complexity. The main goal is to reduce power conception and the execution time without reducing image quality. In this paper, the authors have proposed high parallel processing architecture is presented for four-step search block-matching motion estimation. The proposed method is based on the stoppable clock models. The architecture has been simulated and synthesized with VHDL and ASIC （CMOS 45 nm）. Synthesize results show that the proposed architecture reduces the power consumption and achieves a high performance for real time motion estimation.