Study on Measurement Methods of Multi-Directional Waves—Wave Gauge Array Method

Measuring multi-directional waves with the wave gauge array is one of the fundamental and easily realised methods. In this paper, the wave gauge array is described and the effects of the gauge spacing, the array orientations, etc. of the three array arrangements, i. e., linear array, T-type array and pentagon array, on the resolution of the directional spreading of waves, are investigated experimentally. This study can be used as a reference in the experimental study and the field measurement of directional waves.

Study of A Multi-criteria Evaluation Methodology for Nuclear Fuel Cycle System Based on Sustainability

This paper presents a multi-criteria evaluation methodology for nuclear fuel cycle options in terms of energy sustainability. Starting from the general sustainability concept and the public acceptance questionnaire, a set of indicators reflecting specific criteria for the evaluation of nuclear fuel cycle options are defined. Particular attention is devoted to the resource utility efficiency, environmental effect, human health hazard and economic effect, which represent the different concerns of different stakeholders. This methodology also integrated a special mathematic processing approach, namely the Extentics Evaluation Method, which quantifies the human being subjective perception to provide the intuitionistic judgement and comparison for different options. The once-through option and reprocessing option of nuclear fuel cycle are examined by using the proposed methodology. The assessment process and result can give us some guidance in nuclear fuel cycle evaluation under the constraint of limited data.

Greenhouse gas emission analysis and measurement for urban rail transit: A review of research progress and prospects

Rail transit plays a key role in mitigating transportation system carbon emissions.Accurate measurement of urban rail transit carbon emission can help quantify the contribution of urban rail transit towards urban transportation carbon emission reduction.Since the whole life cycle of urban rail transit carbon emission measurement involves a wide range of aspects,a systematic framework model is required for analysis.This research reviews the existing studies on carbon emission of urban rail transit.First,the characteristics of urban rail transit carbon emission were determined and the complexity of carbon emission measurement was analyzed.Then,the urban rail transit carbon emission measurement models were compared and analyzed in terms of the selection of research boundaries,the types of greenhouse gas(GHG)emissions calculation,and the accuracy of the measurement.Following that,an intelligent station was introduced to analyze the practical application of digital collaboration technology and energy-saving and carbon-reducing system platforms for rail transit.Finally,the urgent problems and future research directions at this stage were discussed.This research presents the necessity of establishing a dynamic carbon emission factor library and the important development trend of system integration of carbon emission measurement and digital system technology.

On-Machine Measurement of the Straightness and Tilt Errors of a Linear Slideway Using a New Four-Sensor Method

Although there are some multi-sensor methods for measuring the straightness and tilt errors of a linear slideway, they need to be further improved in some aspects, such as suppressing measurement noise and reducing precondition.In this paper, a new four-sensor method with an improved measurement system is proposed to on-machine separate the straightness and tilt errors of a linear slideway from the sensor outputs, considering the influences of the reference surface profile and the zero-adjustment values. The improved system is achieved by adjusting a single sensor to di erent positions. Based on the system, a system of linear equations is built by fusing the sensor outputs to cancel out the e ects of the straightness and tilt errors. Three constraints are then derived and supplemented into the linear system to make the coe cient matrix full rank. To restrain the sensitivity of the solution of the linear system to the measurement noise in the sensor outputs, the Tikhonov regularization method is utilized. After the surface profile is obtained from the solution, the straightness and tilt errors are identified from the sensor outputs. To analyze the e ects of the measurement noise and the positioning errors of the sensor and the linear slideway, a series of computer simulations are carried out. An experiment is conducted for validation, showing good consistency. The new four-sensor method with the improved measurement system provides a new way to measure the straightness and tilt errors of a linear slideway, which can guarantee favorable propagations of the residuals induced by the noise and the positioning errors.

Consensus Control With a Constant Gain for Discrete-time Binary-valued Multi-agent Systems Based on a Projected Empirical Measure Method

This paper studies the consensus control of multiagent systems with binary-valued observations.An algorithm alternating estimation and control is proposed.Each agent estimates the states of its neighbors based on a projected empirical measure method for a holding time.Based on the estimates,each agent designs the consensus control with a constant gain at some skipping time.The states of the system are updated by the designed control,and the estimation and control design will be repeated.For the estimation,the projected empirical measure method is proposed for the binary-valued observations.The algorithm can ensure the uniform boundedness of the estimates and the mean square error of the estimation is proved to be at the order of the reciprocal of the holding time(the same order as that in the case of accurate outputs).For the consensus control,a constant gain is designed instead of the stochastic approximation based gain in the existing literature for binary-valued observations.And,there is no need to make modification for control since the uniform boundedness of the estimates ensures the uniform boundedness of the agents’states.Finally,the systems updated by the designed control are proved to achieve consensus and the consensus speed is faster than that in the existing literature.Simulations are given to demonstrate the theoretical results.

Experimental Assessment of the Battery Lifetime in WSN Based on the <i>Duty</i>-<i>Cycle</i><i>Current</i><i>Average</i>Method

A great amount of work addressed methods for predicting the battery lifetime in wireless sensor systems. In spite of these efforts, the reported experimental results demonstrate that the duty-cycle current average method, which is widely used to this aim, fails in accurately estimating the battery life time of most of the presented wireless sensor system applications. The aim of this paper is to experimentally assess the duty-cycle current average method in order to give more effective insight on the effectiveness of the method. An electronic metering system, based on a dedicated PCB, has been designed and developed to experimentally measure node current consumption profiles and charge extracted from the battery in two selected case studies. A battery lifetime measurement (during 30 days) has been carried out. Experimental results have been assessed and compared with estimations given by using the duty-cycle current average method. Based on the measurement results, we show that the assumptions on which the method is based do not hold in real operating cases. The rationality of the duty-cycle current average method needs reconsidering.

航空发动机全生命周期碳排放计量方法研究

航空产业是碳排放八大重点行业之一,航空产业的碳排放主要受航空发动机碳排放的影响,因此亟需开展航空发动机碳排放计量方法研究。以生命周期评价作为航空发动机碳足迹的量化方法,将航空发动机全生命周期碳排放分为燃料周期碳排放与材料周期碳排放,并分别进行统计;将航空发动机系统边界进行划分,对各个阶段进行数据收集,并对数据做出要求,得到一套相对完整的航空发动机碳排放计量方法。本文得到的方法可以从生命周期的角度全面评估航空发动机碳排放,能够为航空发动机全生命周期碳排放计量提供指引,从燃料角度与材料角度为减排提供理论基础。

长距离场地自行车运动员骑行中的迎风面积研究

研究目的:在长距离场地自行车比赛中,当运动员输出功率相近时,空气阻力是影响成绩的主要因素,而运动员迎风面积的测定是空气阻力研究中的关键因素。为精确测定不同形态运动员在不同骑行姿态时的迎风面积,研究采用平面测量法进行测试。研究方法:使用数码相机采集运动员的正面图像信息,利用CAD网格矫正图像畸变,得到了4名运动员不同躯干角度的迎风面积结果。研究结果:(1)迎风面积值在0.32~0.35 m~2之间,其中运动员2在8°和16°时值最大,躯干特征参数占比最大;(2)迎风面积在躯干面积较大时对骑行姿态变化较为敏感,并分析得到了迎风面积的估算模型,可为教练员和运动员的训练与比赛提供较为准确的数据参考。

智能放顶煤技术在特厚煤层上覆含水层保护中的应用

我国内蒙古东部和新疆北部草原地区煤炭及地下水资源丰富,煤矿高强度开采形成的采动裂隙易导通强富水含水层,极易引起上覆岩层的地下水系统破坏,更容易发生突水溃砂事故,尤其含水层下综合机械化放顶煤开采的放煤高度难以控制。以特厚煤层上覆含水层系统保护为研究对象,以含水层保护和水砂灾害安全防控为研究目标,研发特厚煤层上覆含水层保护的智能放顶煤关键技术,应用井工煤矿动力突水溃砂防控技术,得出特厚煤层上覆地下水系统保护的根本途径。研发应用一种智能放顶煤技术,包括顶煤运移跟踪系统、多轮记忆放煤方法及系统。基于水文地质条件精细探查、覆岩破坏高度的实测、顶煤采放高度确定,应用多轮记忆放煤智能放顶煤技术,控制采动裂隙带高度。以应用工作面为例,应用水文地质精细探查与钻探验证、覆岩破坏高度获取、智能放顶煤技术后,在工作面回采过程中实现了上覆含水层水砂灾害的安全精准控制,有效保护了煤层上覆强富水含水层。

航空液压管路系统振动疲劳寿命评估的响应谱方法

目的实现航空液压管路系统在一致/多点激励作用下,高周疲劳寿命的准确高效获取。方法考虑管内流体Coriolis力和夹具的附加阻尼效应,建立一致/多点激励作用下,航空液压管路系统振动疲劳寿命评估的响应谱方法。首先,采用复模态叠加法,在状态空间对其控制方程进行降阶,推导出一致/多点激励作用下航空液压管路随机应力响应的显式表达。然后,基于现有的疲劳响应谱方法,依次引入与模态速度与基础激励相关的广义相关系数,并计入非比例阻尼以及多点激励效应,建立一致/多点激励作用下航空液压管路系统疲劳响应谱方法组合格式。结果采用雨流计数法验证了本文方法的计算精度,并讨论了分析效率。同时,探究了管内流体流速与激励的部分相干性对于管路系统疲劳寿命的影响。结论本文方法计算效率极高,且计算精度稳定,并考虑了管内流体负载与多点激励效应对疲劳寿命影响,能够满足工程中复杂管路系统振动疲劳的分析需求。

多路绝对激光测距仪精密三维控制网的建立与解算

建立高精度三维控制网是实现大型粒子加速器等精密工程测量的前提条件,目前主要通过间接测量两点间距离或者自由设站实现,而多路绝对激光测距仪可在0.02~30 m范围内直接测量空间中两点间距离,利用高精度绝对测距值可建立高精度的三维测边控制网。基于多路绝对激光测距仪高精度绝对测距性能,建立仅含控制点间距离的秩亏自由网平差模型,通过任意初值选取,应用改进的LM算法迭代求解非线性超定方程组实现坐标概算,得到方程组的一组解作为未知数的近似值进行整网平差,获得高精度控制点坐标。实验数据分析表明,在8 m×3.5 m×2.5 m的实验范围内,建立控制点平均点位精度优于±1.14μm的三维测边网,可满足现代工业生产中对安装定位的高精度需求。

基于多物理场耦合的变压器噪声及降噪措施研究

随着电压等级、变压器的容量以及数量的不断提升,变压器的噪声污染日益严重,采取有效措施降低变压器噪声已迫在眉睫。基于有限元仿真平台搭建了110 kV系列变压器模型,采用电-磁-力-声多物理场耦合的方法对不同容量变压器的声压级分布以及应力分布情况进行仿真分析,揭示了不同容量变压器噪声与磁通密度、磁致伸缩效应等参数的关系,依据所得结果提出了基于改进变压器铁心材料和改变铁心夹紧力等方法的降噪措施。

基于多试样法的PVC塑料J-R阻力曲线的简便测量方法

获得PVC材料的J-R阻力曲线以及断裂韧度J_(IC)的难点在于裂纹扩展量Δa的测量,传统染色处理以及三维测量等方法过程复杂且测试成本高。由于塑料的易切割性,可以简化Δa的测量过程。因此,基于多试样法,提出根据规范的测点要求对加载后的试件沿着裂纹纵向切割成若干片、再通过工业电子显微镜测量每个切割片上的裂纹长度,从而获得Δa的二维测量方法。通过GB 21143—2014和ASTM D6068-10两个标准,应用该方法均能获得相对一致的J-R阻力曲线和J_(IC)值,测试结果有效且准确。其中根据GB 21143—2014获得PVC的J_(IC)值为8.03 kJ/m^(2),J-R阻力曲线拟合方程的系数为9.93,指数为0.15;根据ASTM D6068-10获得PVC的J_(IC)为8.31 kJ/m^(2),J-R阻力曲线拟合方程的系数为12.7,指数为0.3;表明ASTM D6068-10获得PVC的断裂韧度J_(IC)值和拟合方程的系数、指数均大于GB 21143—2014。由于PVC材料与金属材料性能的差异,得出ASTM D6068-10更适用于测试PVC材料的J-R阻力曲线和J_(IC)值的结论。该方法将传统的裂纹染色处理和三维测量等复杂操作简化为切片和二维测量,简化测量过程,降低了测量成本,可普及应用于塑料断裂韧性的测量。

机车车辆制动电阻温升试验用轻量化测温系统的设计

针对轨道交通机车车辆制动电阻温升试验时温度测量的需求,设计了一款基于图形化编程语言LabVIEW的多通道温度测量系统,可以实现14通道的温度同时采集、显示、绘图及数据保存。为提高系统测量精度,以测量系统的实测值和标准源约定真值作为多项式拟合的数据源,采用最小二乘法曲线拟合的方法对测量系统进行标定,来降低测量误差、提高测量精度。测试结果表明,系统运行稳定可靠,测量精度显著提高。

GNSS整周模糊度研究现状与展望

载波相位测量是全球导航卫星系统(GNSS)实现高精度定位的一个重要观测量。在现阶段,自动驾驶、智慧城市等领域的技术越来越成熟,高精度定位能在这些领域得到广泛的应用,甚至促进这些领域的快速发展,是当前卫星导航领域的热点。快速可靠地确定整周模糊度是载波相位测量中的关键,也是提高GNSS定位精度的关键。本文整理了各种整周模糊度的解算方法,其中重点论述了三频载波模糊度解算(TCAR)方法、递进模糊度整数解算(CIR)方法、最小二乘模糊度去相关平差(LAMBDA)算法等整周模糊度的解算方法及其研究进展,并探讨后续研究的方向。

空气标准等温加热修正Brayton循环:(2)多目标优化

基于第1部分对循环功率和效率特性的研究,进一步以效率、生态学函数、功率和功率密度为优化目标,以压缩比为优化变量,利用NSGA-Ⅱ算法对内可逆空气标准等温加热修正Brayton循环进行不同目标组合的单、双、三和四目标优化,并利用偏差指数对3种决策方式的优化结果进行分析对比,从而寻找最优解集。结果表明三目标优化中偏差指数最小,为0.129 2。故多目标优化能更有效地找到最优解集。研究成果可为Brayton热机循环的优化设计提供一定参考。

Extension of TOPSIS for fuzzy multi-attribute decision making problem based on experimental analysis

This paper is concerned with a technique for order performance by similarity to ideal solution（TOPSIS） method for fuzzy multi-attribute decision making,in which the information about attribute weights is partly known and the attribute values take form of triangular fuzzy numbers.Considering the fact that the triangular fuzzy TOPSIS results yielded by different distance measures are different from others,a comparative analysis of triangular fuzzy TOPSIS ranking from each distance measure is illustrated with discussion on standard deviation.By applying the most reasonable distance,the deviation degrees between attribute values are measured.A linear programming model based on the maximal deviation of weighted attribute values is established to obtain the attribute weights.Therefore,alternatives are ranked by using TOPSIS method.Finally,a numerical example is given to show the feasibility and effectiveness of the method.

基于生产周期的包装印刷品碳足迹测算方法研究

目的 对包装印刷品的生产周期碳足迹核算流程、核算方法、数据收集等方面进行探讨,归纳出包装印刷品生产周期碳足迹测算中存在的问题,并提出解决测量问题和降低生产周期碳足迹的可行策略和建议,为国内外包装印刷企业产品碳足迹测算和“碳中和”提供参考。方法 结合包装印刷企业实际生产数据和印刷品碳足迹国际核算标准,以化妆品包装盒为例进行碳足迹现场测算研究。结果 从工艺角度看,包装印刷品生产周期碳足迹绝大部分来源于造纸、印刷、覆膜生产过程,其次是糊盒、上光等印后加工过程,从原辅材料和能源角度看,碳足迹绝大部分来源于纸张、电力、胶水。结论 对生产设备进行节能降耗、选择低碳原辅材料代替高碳原辅材料和创新产品结构设计将是降低包装印刷品生产周期碳足迹的有效措施。

基于约束优化的木材燃烧多光谱真温测量

木材具有易燃性,在燃烧时产生的大量热辐射会对周围环境造成极大破坏,所以需要对木材燃烧的真温值进行实时监测。多光谱辐射测温是有效的非接触测量方法,该方法需要假设发射率模型进行真温反演,当发射率未知时,无法准确反演真温值。针对此问题,首先,将多光谱温度反演问题转换为约束优化问题;然后,利用坐标轮换约束优化算法求解被测目标温度值;最后,使用多光谱辐射测温仪对燃烧状态的红松木火焰进行真温测量,并与热电偶测量结果进行对比。根据实验结果表明:多光谱辐射测温法得到的结果最大绝对误差为28.174 K,最大相对误差为2.252%。验证了坐标轮换约束优化法的实用性与可行性,为后续木材燃烧火焰温度高精度测量提供了有效的依据。

基于加权融合矩阵系统聚类的多机床温度测点选择方法

针对不同数控机床热误差建模中温度关键点的选择和优化问题,提出有效减少温度测点并提高热误差预测精度的新方法.所提方法通过建立各个温度信号序列之间的相关性和差异性,对温度测点进行有效分类和选择.在系统聚类的基础上,将变量间的相关系数与欧氏距离矩阵进行权重赋值后加以融合,以优化各测点之间的共线性.利用灰色关联分析判断测点与热误差间的紧密程度并提取各类子集中的最优测点,以优化后的测点为输入构建基于支持向量回归的热误差预测模型.为了确定权重系数、聚类数、支持向量回归的参数,采用遗传算法进行参数寻优得到最优的预测模型.在多台机床上进行实验,列举出3台不同型号机床的验证分析结果,使用所提方法的预测均方根误差与原始测点的相比分别下降了24%、71%和62%.结果表明,所提方法在不同机床上均能实现在大幅减少传感器数量的前提下有效提高热误差模型预测精度;所提方法具有良好的通用性,与其他方法相比,所提方法的预测性能更强.