Integrated Design and Accuracy Analysis of Star Sensor and Gyro on the Same Benchmark for Satellite Attitude Determination System

As an important sensor in the navigation systems,star sensors and the gyro play important roles in spacecraft attitude determination system.Complex environmental factors are the main sources of error in attitude determination.The error influence of different benchmarks and the disintegration mode between the star sensor and the gyro is analyzed in theory.The integrated design of the star sensor and the gyro on the same benchmark can effectively avoid the error influence and improves the spacecraft attitude determination accuracy.Simulation results indicate that when the stars sensor optical axis vectors overlap the reference coordinate axis of the gyro in the same benchmark,the attitude determination accuracy improves.

Satellite Derived Geospatial Irrigation Performance Indicators for Benchmarking Studies of Irrigation Systems

Development of irrigation infrastructure and its efficient management is the primary concern for sustainable food production. The assessment of irrigation infrastructure creation, its utilization, diagnostic evaluation of the various performance indices (monitoring) are important to measure the efficiency. Benchmarking of Irrigation Systems (BIS) is for the diagnostic analysis of irrigation performance indicators comprising of Irrigation Infrastructure System (IIS), Agricultural System (AS), Water Delivery Dynamics (WDD). Since, the performance of an irrigation command varies with space and time, utilization of spatial information technologies viz. Remote Sensing (RS), Geographical Information Systems (GIS), Global Positioning Systems (GPS) useful to provide spatial information on several indices in the process of benchmarking (BM). Information requirements for BIS at different stages, utilization of spatial information technologies to derive irrigation performance indicators was discussed with suitable examples and demonstrated in this study. The studies carried out indicates that the geospatial approach for BIS enabled the improvements in data collection methods, diagnostic analysis, spatio-temporal visualisation of BM indicators at disaggregated canal level which would be useful for decision support during the corrective management measures. The conjunctive use of multi-date (medium resolution) satellite data, high spatial resolution data, field data on water deliveries was found to be an alternative to the conventional non-spatial approaches for BIS and thereby better water resources planning and management.

Analysis of Network Performance for Computer Communication Systems with Benchmark

This paper introduced a performance evaluating approach of computer communication system based on the simulation and measurement technology, and discussed its evaluating models. The result of our experiment showed that the outcome of practical measurement on Ether-LAN fitted in well with the theoretical analysis. The approach we presented can be used to define various kinds of artificially simulated load models conveiently, build all kinds of network application environments in a flexible way, and exert sufficiently the widely-used and high-precision features of the traditional simulation technology and the reality, reliability, adaptability features of measurement technology.

SDFPB在九层Benchmark钢框架中的隔震性能研究

为研究SMA-复摩擦摆支座(Shape Memory Alloys Double Friction Pendulum Bearing,SDFPB)在多、高层建筑结构中的隔震性能和安全性,基于OpenSees建立了SDFPB的有限元模型,分析了SDFPB力学性能影响因素,将其应用于九层Benchmark钢框架结构中,对比了隔震结构和非隔震结构的地震响应。研究表明,SDFPB隔震系统可以改善九层Benchmark钢框架动力特性,显著削弱上部结构在地震作用下的楼层加速度、层间位移角和层间剪力,有效控制隔震层位移,在多、高层建筑结构中可发挥良好隔震效果并提升安全性。

Analysis of Irrigation Systems Employing Comparative Performance Indicators： A Benchmark Study for National Irrigation and Communal Irrigation Systems in Cagayan River Basin

Comparative performance analysis of four irrigation schemes within Cagayan River Basin was assessed using comparative performance indicators between the years 2008 and 2012. The objectives were to establish benchmarks for both productivity and performance of irrigation schemes along the valley and to inquire whether small schemes function better than large schemes. The performance evaluation study of the systems composed of three general performance indicators, based on three domains-（1） system operation performance; （2） agricultural productivity and economics; （3） financial performance. Each indicator was assessed based on the prescribed descriptors used by the International Water Management Institute （IWMI） and Food and Agriculture Organization （FAO）. Analysis showed an overall system performance efficiency of 59%, 55%, 47% and 36% for Magat River Integrated Irrigation System （MARI1S）, Lucban, Garab and Divisoria Communal Irrigation Systems （CIS）, respectively. In terms of annual productivity performance, Lucban CIS dominates the three other systems with 0.35 kg/m3, which was classified as moderately performing system, while the rest were classified with low productivity index. Financial sustainability of the systems were extremely poor with cost recovery ratio of 0, 0.33, 0.41 and 0.49 for Divisoria, Garab, Lucban and MARIIS, respectively, which were exceptionally below the standard value of at least one. Also, analysis of the indicators revealed that on average, large schemes performed similarly to small-scale schemes, but small schemes were more variable, particularly in input-use efficiency. The benchmarking study will provide strategic information to policy makers of agricultural and irrigation agencies on the existing weaknesses of irrigation systems in the country and determine in a more quantifiable terms levels of potential improvement and intervention targets.

DEVELOPING AN ENERGY BENCHMARKING SYSTEM FOR HOTEL BUILDINGS USING THE STATISTICAL METHOD AND THE SIMULATION-BASED APPROACH

Due to increased tourist activity,many cities now have a large number of hotel buildings.It is necessary to establish measures to evaluate energy use intensity to effectively manage energy consumption in this sector.This study uses a combined strategy to establish an energy benchmark for hotel buildings in Vietnam.First,a survey and analysis of actual building stock data of 50 hotels in Danang,Vietnam,was conducted.The survey-based benchmark and its related data was then used to build a reference energy model to estimate an energy benchmark for other climatic regions in Vietnam by using the energy simulation method.The results reveal that the average energy use intensity for hotels in Danang was 87.4 kWh/m2.year or 8628.6 kWh/guestroom.year.However,this study proposes that because of the differing expectations of comfort standards,hotels of different grades should have separate benchmarks.This study also proposes an energy intensity-based rating scale,including 7 grades from the least energy intensive(grade A)to the most energy intensive(grade G),which can be used to manage,label,or encourage sustainable energy use in hotel buildings.The relationship between the energy use intensity and the occupancy rate of the hotels was reported,compared,and explained.It was found that occupancy rate has no significant impact on the energy use intensity.From the survey result,some predictive models were developed to estimate annual energy consumption of hotel buildings based on their grades.The simulated benchmarks for other regions were also achieved.The results demonstrate many potential applications in the management,design and construction,and renovation of this building type.

Medium-term Air Quality Benchmarking for Ecosystem Monitoring and Sustainability Planning: Case Study Dallas County (U.S.A.) 2015 to 2020

Medium-term air quality assessment,benchmarking it to recent past data can usefully complement short-term air quality index data for monitoring purposes.By using daily and monthly averaged data,medium-term air quality benchmarking provides a distinctive perspective with which to monitor air quality for sustainability planning and ecosystem perspectives.By normalizing the data for individual air pollutants to a standard scale they can be more easily integrated to generate a daily combined local area benchmark(CLAB).The objectives of the study are to demonstrate that medium-term air quality benchmarking can be tailored to reflect local conditions by selecting the most relevant pollutants to incorporate in the CLAB indicator.Such a benchmark can provide an overall air quality assessment for areas of interest.A case study is presented for Dallas County(U.S.A.)applying the proposed method by benchmarking 2020 data for air pollutants to their trends established for 2015 to 2019.Six air pollutants considered are:ozone,carbon monoxide,nitrogen dioxide,sulfur dioxide,benzene and particulate matter less than 2.5 micrometres.These pollutants are assessed individually and in terms of CLAB,and their 2020 variations for Dallas County compared to daily trends established for years 2015 to 2019.Reductions in benzene and carbon monoxide during much of 2020 are clearly discernible compared to preceding years.The CLAB indicator shows clear seasonal trends for air quality for 2015 to 2019 with high pollution in winter and spring compared to other seasons that is strongly influenced by climatic variations with some anthropogenic inputs.Conducting CLAB analysis on an ongoing basis,using a relevant near-past time interval for benchmarking that covers several years,can reveal useful monthly,seasonal and annual trends in overall air quality.This type of medium-term,benchmarked air quality data analysis is well suited for ecosystem monitoring.

浅析数字化在汽车Benchmarking中的应用

竞争车解析对标是汽车Benchmarking的基础工作,现行业竞争车解析对标参数采集均依靠人工作业,工作效率低下。结合业务实践,文章研究了一套自动拍照、自动称重的数字化信息采集系统,通过软硬件结合实现竞争车解析对标参数采集、数据整理、数据传输等全链条业务自动化。该方法的运用可大幅提升整车Benchmarking工作效率,进而缩短产品开发周期,实现效率与效益双提升。

铝合金板冲压成形Benchmark试验与有限元仿真

采用NUMISHEET2002会议提出的杯形件拉深Benchmark试验方案,在不同压边力工况下,对铝合金板6111-T4的拉深性能、各向异性行为、起皱缺陷进行了试验研究。研究表明:各向异性系数小并未对铝合金板的成形性能产生较大影响,通过增大压边力能有效解决起皱问题,铝合金板6111-T4具有良好的冲压成形性能。基于自主研发的冲压成形CAE软件KMAS平台,对Benchmark试验进行了仿真验证,与试验结果对比表明:KMAS软件采用的Barlat-Lian各向异性屈服准则和动力半显式算法能够准确模拟铝合金板的冲压成形。

Benchmark模型结构两阶段损伤诊断试验分析

提出了一种基于结构振动特性的两阶段损伤诊断方法,以国际结构控制协会与美国土木工程学会(IASC-ASCE)提出的健康监测Benchmark模型结构为例,对其在力锤脉冲激励和环境激励下的试验数据进行分析,对不同的损伤模式进行了损伤定位和损伤程度的估计。结果表明,在模型误差、测量噪声、质量与刚度分布不确定性等因素的影响下,该两阶段损伤诊断方法能够取得令人满意的损伤识别结果。

基于Benchmark模型的抑制屈曲支撑耗能减振作用分析

抑制屈曲支撑可在拉压循环荷载作用下均达到屈服,拉压承载力基本一致,滞回曲线稳定饱满,耗能能力强。基于Benchmark模型对安装抑制屈曲支撑的钢框架结构基于ANSYS的数值分析表明,抑制屈曲支撑不仅可使结构在小震时的抗侧刚度有所提高,同时在大震时通过其往复滞回变形发挥耗能减振作用,大大地降低了结构的地震响应,提高了结构的抗震性能。同时分析表明考虑高阶振型影响的能力谱分析方法是一种更为精确的分析方法。

超高层建筑结构benchmark模型及其地震反应分析

参照上海中心,根据设定的性能目标设计了一个超高层建筑结构的benchmark模型用于超高层建筑结构抗震研究。该结构总高度为606.1 m,抗震设防烈度为7度,场地类别为IV类,设计分组为第一组。该结构采用巨型框架-核心筒-伸臂桁架钢-混凝土混合结构体系,8道环带桁架将结构分为9个区,环带桁架与型钢混凝土巨柱共同构成了巨型框架结构体系,并通过6道伸臂桁架与核心筒相连,共同承受水平荷载。利用PERFORM-3D软件建立了结构的非线性数值计算模型,对结构进行了弹塑性地震反应分析,验证了结构的抗震性能。计算结果表明,满足现行设计规范的该超高层结构在大震作用下具有较大的安全余量。

基于特征灵敏度的Benchmark结构损伤诊断

为准确地评估结构的健康状况,提出了一种两阶段损伤诊断方法.引入柔度差值斜率的概念确定结构可能出现损伤单元的位置,采用基于二阶特征灵敏度的方法确定可能损伤单元的损伤程度.应用该方法对由国际结构控制协会与美国土木工程学会(IASC-ASCE)提出的健康监测Benchmark结构进行了分析.结果表明,两阶段损伤诊断方法能够准确地定出可能损伤单元的位置与损伤程度,识别结果与真实的损伤接近,说明该诊断方法是有效的.

基于小波包分析的Benchmark结构损伤预警试验研究

在基于小波包能量谱的结构损伤预警方法基础上,开展了Benchmark结构损伤预警的试验研究。通过Benchmark试验模型模拟结构的多种损伤状态,并采集模型在结构损伤前后的动力响应,在此基础上计算了结构损伤预警的小波包能量谱及其损伤预警指标。试验结果表明:基于小波包能量谱的结构损伤预警指标具有良好的损伤预警能力,可以准确地判定结构初期损伤的发生。

基于ANSYS软件benchmark模型耗能减振控制分析

本文系统介绍了当前国际结构振动控制的公共平台———Benchm ark模型,首次给出使用通用有限元软件ANSYS对第3阶段20层非线性钢框架抗震结构的有限元建模,结果表明,模态、无控地震反应分析结果和ASCE给出的MATLAB结果相同。利用粘滞阻尼器对此模型的耗能减振数值仿真分析的结果表明:粘滞阻尼器是一种性能很好的阻尼器,使用本文给出ANSYS的Benchm ark有限元模型来进行耗能减振控制分析是方便的、可行的。

Benchmarking技术在汽车开发领域中的应用

介绍了Benchmarking技术的概念;综合国内外汽车发展的历史和现状,针对我国汽车开发经验、知识积累不足问题,引入了Benchmarking技术的样车分析技术体系,细化了样车Benchmarking的流程,说明了Benchmarking技术的应用过程。最后介绍了目前Benchmarking技术在汽车开发知识库系统中的应用现状。

环境激励下Benchmark结构损伤识别的试验研究

针对结构健康监测中如何利用在线监测数据进行健康诊断的问题,基于时间序列分析提出了一种新的损伤识别方法。首先,获得结构健康状态的监测数据作为参考状态样本,对各数据样本建立ARMA模型并计算模型残差的方差。然后,将未知状态的监测数据作为待检状态样本,代入已建立的参考状态ARMA模型计算新的残差方差。计算发现,损伤前后两状态模型残差方差存在差异。因而,提出以残差方差之比作为损伤敏感特征,并建立基于F分布的假设检验来辨识结构的状态并预警损伤。最后,以Benchmark结构在环境激励下的试验为例,运用本文方法进行了损伤识别研究。结果表明,基于ARMA模型残差方差的损伤敏感特征可准确地区别结构的健康状态和损伤状态,具备结构在线实时损伤识别的应用价值。

基于健康监测Benchmark结构的损伤识别方法

研究目的:由于受外部载荷、环境作用、灾害、人为等因素的影响,桥梁结构在服役期间会出现损伤,结构性能下降,其安全性己经引起人们的高度重视。如何去诊断桥梁结构的损伤,对其健康状况进行诊断和监测,己成为当今函待解决的一个重要课题。研究结论:针对桥梁健康监测Benchmark结构,基于加速度响应的自功率谱与主元分析法并结合马氏距离,提出结构整体损伤程度的评估方法:(1)提出的桥梁健康监测Benchmark结构损伤诊断方法可直接利用实测自功率谱进行损伤识别,不需要模态参数,不要求有完整的模态测试数据,因而避开了实际动测时一些模态参数的测不准及实测模态不完整问题;(2)损伤识别过程是通过分析实测自功率谱的数据特征、数据结构来完成的,不需建立结构的力学模型,因而对结构形式、约束方式及边界条件均没有特殊的要求;(3)采用力锤人工激励及SISO的动测方法,激励设备简单,操作方便;(4)本文方法对于在役桥梁的健康监测和损伤诊断具有一定参考价值。

One to One营销优化算法的BenchMark验证方法

该文针对OnetoOne营销优化问题,提出了一种BenchMark验证方法。基于这一BenchMark验证方法,对原始Simplex法、DFS法和LIPSOL法进行了基于理论的BenchMark验证和基于MATLAB的BenchMark验证,给出了仿真结论,证明了提出的BenchMark验证方法的有效性。

地震激励下斜拉桥振动控制Benchmark模型研究

为了在地震波激励下对大跨桥梁结构建立一套振动控制系统评价体系,比较不同控制策略的控制效果,将艾默生纪念桥(Emerson Memorial Bridge)作为斜拉桥振动控制的Benchmark模型,用以研究地震激励下斜拉桥振动控制所采取的各种控制算法和装置的有效性。系统总结十余年来各国学者在该研究中涉及到的各种传统控制算法以及智能算法,阐述了该桥被动控制、主动控制、半主动控制、混合控制的应用情况,对未来的研究趋势进行展望。以艾默生纪念桥为例,选取新型主动EMD阻尼器作为控制装置,实施基于模糊推理的智能控制。将EMD装置的速度作为模糊控制器输入,制定模糊规则,快速、有效地确定EMD装置输出电压,从而对该桥在线实时控制。数值仿真结果表明:18项控制指标接近于样本控制,尤其对基础处剪力、倾覆力矩以及桥塔处拉索的减振控制效果明显。