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橡胶树魏克汉种质成龄树经预割诱导后次生乳管分化的比较 被引量:1
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作者 史敏晶 张世鑫 +3 位作者 晁金泉 吴绍华 杨署光 田维敏 《热带作物学报》 CSCD 北大核心 2021年第9期2555-2562,共8页
巴西橡胶树树干中次生乳管列的多少与胶乳产量密切正相关,而割胶伤害能诱导次生乳管分化。分析不同魏克汉种质成龄树在预割伤害后树皮次生乳管的分化,不仅为不同种质鉴定和评价提供依据,也为成龄大树割胶后次生乳管分化能力提供预测。... 巴西橡胶树树干中次生乳管列的多少与胶乳产量密切正相关,而割胶伤害能诱导次生乳管分化。分析不同魏克汉种质成龄树在预割伤害后树皮次生乳管的分化,不仅为不同种质鉴定和评价提供依据,也为成龄大树割胶后次生乳管分化能力提供预测。采用碘-溴染色方法和石蜡切片技术,对不同种质材料新分化的次生乳管进行了统计分析。研究结果表明,选取的110份魏克汉种质预割后新分化的次生乳管列数不同,具有明显的种质特征。根据分化次生乳管列数的多少,将预割诱导乳管分化的级别由低到高分为1、2、3、4级。在110份种质中,对应1级32份、2级49份、3级24份和4级5份的种质,所占比例分别为29.09%、44.55%、21.82%和4.55%,可见,分化能力强的种质占比较低,大部分种质为2级乳管分化。国外直接引种和国内自主选育的种质在预割诱导分化能力上也存在差异。在110份种质中,国外引种58份种质中对应分化能力1、2、3、4级的种质占比分别为29.31%、44.83%、22.41%以及3.45%;国内选育的52份种质中对应1、2、3、4级的种质占比分别为28.85%、44.23%、21.15%和5.77%;可见,国内选育种质受预割诱导乳管分化的能力优于国外引种的种质,尤其是4级分化能力的种质比例明显高于国外引种的种质。不同系列来源的种质乳管分化能力也存在差异,其中,国外PB、RRIM和RRIC系列和国内的大岭、海垦和大丰系列表现出较强的乳管分化能力。比较分析2个杂交组合后代的乳管分化情况发现,PB86×PR107的4份子代中次生乳管有3份为3级,1份为4级,后代表现出较强的乳管分化能力;而RRIM600×PR107的6份子代中1级2份,2级2份,3级2份,可见其后代乳管分化能力略差。PB86和PR107后代的乳管分化表现出较强的双超亲现象,可作为优良的育种亲本。通过预割判断乳管分化能力不仅为魏克汉种质鉴定和评价奠定基础,也为橡胶树高产育种以及早熟、晚熟品种的早期预测提供有效指标。 展开更多
关键词 橡胶树 魏克汉种质 预割 次生乳管分化 早期
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基于预割缝试验的水泥土稳定RAP混合料抗裂性能研究 被引量:2
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作者 彭波 杨中长 +2 位作者 任自铭 吴世园 杜冰洁 《重庆交通大学学报(自然科学版)》 CAS CSCD 北大核心 2022年第5期92-99,共8页
为分析水泥土稳定RAP混合料的抗裂性能,在最佳含水率和最大干密度下成型不同配比的试件,并对其进行收缩试验和断裂韧度试验。试验结果表明:随着灰土掺量和水泥剂量增加,混合料干缩系数和温缩系数整体上呈现增长趋势,当混合料处于5~-5℃... 为分析水泥土稳定RAP混合料的抗裂性能,在最佳含水率和最大干密度下成型不同配比的试件,并对其进行收缩试验和断裂韧度试验。试验结果表明:随着灰土掺量和水泥剂量增加,混合料干缩系数和温缩系数整体上呈现增长趋势,当混合料处于5~-5℃的温度区间时,温缩系数出现峰值,且峰值大小随水泥剂量的增加而增大。混合料断裂韧度试验结果表明:水泥土稳定RAP混合料的断裂韧度随水泥剂量增加或灰土掺量减少而增大,表明混合料抗裂纹扩展能力也随着增强。拟合结果表明:柔度和收缩系数之间具有较高的相关性,说明柔度能准确地反映混合料的抗收缩性能。基于此,可以将断裂韧度和柔度作为冷再生混合料抗裂性能的评价指标。 展开更多
关键词 道路工程 抗裂性能 预割缝三点梁弯曲 半刚性基层 柔度 再生沥青混合料
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橡胶树1981’IRRDB野生种质预割诱导次生乳管分化的比较分析
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作者 史敏晶 张世鑫 +4 位作者 晁金泉 李言 邓小敏 胡彦师 田维敏 《热带作物学报》 CSCD 北大核心 2022年第2期303-310,共8页
巴西橡胶树树干树皮中的次生乳管是天然橡胶合成和贮存的主要组织,次生乳管列的多少与胶乳产量密切正相关。割胶是天然橡胶生产中的核心环节,是当前获得天然橡胶的唯一途径,而割胶伤害能诱导次生乳管分化。采用碘-溴染色方法和石蜡切片... 巴西橡胶树树干树皮中的次生乳管是天然橡胶合成和贮存的主要组织,次生乳管列的多少与胶乳产量密切正相关。割胶是天然橡胶生产中的核心环节,是当前获得天然橡胶的唯一途径,而割胶伤害能诱导次生乳管分化。采用碘-溴染色方法和石蜡切片技术,观察预割前后1981’IRRDB野生种质成龄树的树皮结构,对不同种质预割前后黄皮层和水囊皮区域的乳管列进行统计,并分析新分化的次生乳管列。研究结果表明,选取的85份8年生野生种质在自然条件下的乳管分化能力普遍较弱,黄皮层和水囊皮中成列的次生乳管数量均较少,2个部位合计乳管列数普遍低于8列。预割后不同种质水囊皮中次生乳管列数普遍增多,但黄皮层尚无明显变化。根据伤害诱导分化新的次生乳管列数的多少,将预割诱导乳管分化的能力由低到高分为1、2、3级,分别对应于新分化乳管列数为少于2列、2~3列(含2列)、3~4列(含3列)。在85份种质中,对应1级57份、2级23份、3级5份的种质,所占比例分别为67.06%、27.06%、5.88%,可见,诱导分化次生乳管能力强的种质占比较低,大部分种质为1、2级乳管分化,3级分化能力的种质极少。被诱导新分化次生乳管的能力与种质在自然条件下的分化能力有关,尤其是高乳管分化能力的种质通常在自然条件下也有较强的分化乳管的能力。通过预割判断乳管分化能力不仅为野生种质鉴定和评价奠定基础,也为橡胶树高产育种以及早熟、晚熟品种的早期预测提供有效指标。 展开更多
关键词 橡胶树 野生种质 预割 次生乳管分化
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预割对橡胶树胶乳生理的影响
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作者 方分分 刘实忠 +1 位作者 杨文凤 校现周 《热带农业科技》 2008年第3期6-8,24,共4页
试验研究了巴西橡胶树在不同的预割后正式割胶时的胶乳生理效应,结果表明:与不预割树相比,经预割处理后的橡胶树干胶含量略微下降,硫醇含量可能因为株间差异因而变化不明显,无机磷含量上升,胶乳中的蔗糖含量下降,表明预割可以增强橡胶... 试验研究了巴西橡胶树在不同的预割后正式割胶时的胶乳生理效应,结果表明:与不预割树相比,经预割处理后的橡胶树干胶含量略微下降,硫醇含量可能因为株间差异因而变化不明显,无机磷含量上升,胶乳中的蔗糖含量下降,表明预割可以增强橡胶树的整体代谢。 展开更多
关键词 橡胶树 预割 生理参数
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自由面预割缝下底切滚刀铣削破岩机理研究
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作者 张钦 苏金华 +6 位作者 李爱军 徐彬彬 闫晓磊 刘定 杨俊奇 唐进涛 李洪盛 《现代隧道技术》 CSCD 北大核心 2023年第6期192-198,共7页
为提高底切滚刀铣削破碎硬岩性能、降低其破岩载荷,建立预割缝下底切滚刀铣削破碎硬岩数值模型,研究不同铣削厚度和割缝参数(割缝间距、割缝深度)组合对底切滚刀破岩性能的影响规律,揭示预割缝对底切滚刀破岩的影响机制。结果表明,割缝... 为提高底切滚刀铣削破碎硬岩性能、降低其破岩载荷,建立预割缝下底切滚刀铣削破碎硬岩数值模型,研究不同铣削厚度和割缝参数(割缝间距、割缝深度)组合对底切滚刀破岩性能的影响规律,揭示预割缝对底切滚刀破岩的影响机制。结果表明,割缝间距和滚刀直径相同时滚刀铣削预割缝条件下的岩石可以等效为滚刀铣削无侧限压力岩石,与无割缝岩石相比截割力减小率降低超30%;底切滚刀铣削厚度和割缝间距的匹配关系对破岩比能的影响显著,在最佳破岩比能时其组合关系为截深20 mm、割缝间距100 mm;分析岩屑分形维数和破岩比能之间的关系,比能耗随着分形维数的增加呈线性增大。 展开更多
关键词 底切滚刀 预割 铣削厚度 裂纹扩展 破岩性能
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顶板钻孔割缝导向水压裂缝扩展的现场试验 被引量:53
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作者 黄炳香 王友壮 《煤炭学报》 EI CAS CSCD 北大核心 2015年第9期2002-2008,共7页
在坚硬顶板定向水力致裂原理性试验成功的基础上,在综采工作面端头超前支护段内进行了坚硬顶板钻孔预割缝定向水力致裂的半工业性试验,分析钻孔割缝对引导水压裂缝扩展的作用。大同塔山煤矿8102工作面试验结果表明,钻孔孔壁水压裂缝沿... 在坚硬顶板定向水力致裂原理性试验成功的基础上,在综采工作面端头超前支护段内进行了坚硬顶板钻孔预割缝定向水力致裂的半工业性试验,分析钻孔割缝对引导水压裂缝扩展的作用。大同塔山煤矿8102工作面试验结果表明,钻孔孔壁水压裂缝沿预割缝槽优先起裂,预开槽对坚硬顶板水力致裂的起裂起到了定向作用。水压裂缝定向起裂后,受地应力场等综合影响,水压裂缝会出现空间转向。采动影响会改变致裂钻孔周围的应力分布,进而影响裂缝的定向扩展效果;因此,坚硬顶板定向水力致裂应考虑采动应力影响,注意与采动的协调配合。定向水压裂缝可穿岩层间层面扩展。钻孔预割缝定向水力致裂的实质是通过预割缝来控制裂缝的定向起裂,引导裂缝的扩展方向;并配合地应力、采动应力、致裂工艺等使导向裂缝尽量满足工程要求。 展开更多
关键词 坚硬顶板 钻孔预割 定向水力致裂 裂缝扩展
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用铝板压制变径封头杜绝裂纹的新式措施
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作者 赵忠刚 赵政策 曹文明 《金属加工(热加工)》 2017年第7期41-42,共2页
着重阐述封头的压制过程,并分析论述了封头发生龟裂或裂纹的各种原因,详细讲解了封头后续压制的改进方法,切实从源头上杜绝了利用板材直接压制大直边变径封头的龟裂和裂纹现象。
关键词 封头 初压 裂纹或龟裂 预割
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An Inhomogeneous Distribution Model of Strong Earthquakes along Strike-Slip Act ive Fault Segments on the Chinese Continent and Its Implication in Engineering Seismology 被引量:1
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作者 ZhouBengang RanHongliu +1 位作者 SongXinchu ZhouQin 《Earthquake Research in China》 2004年第2期200-211,共12页
Through the statistical analysis of earthquake distribution along 51 strike-sli p active fault segments on the Chinese continent, we found that strong earthquak e distribution along the seismogenic fault segments is i... Through the statistical analysis of earthquake distribution along 51 strike-sli p active fault segments on the Chinese continent, we found that strong earthquak e distribution along the seismogenic fault segments is inhomogeneous and the dis tribution probability density p(K) can be stated as p(K)=1.1206e -3.947K in which K=S/(L/2), S refers to the distance from earthquake epicenter to the center of a fault segment, L is the length of the fault segment. The above model can be utilized to modify the probability density of earthquake occurrence of t he maximum magnitude interval in a potential earthquake source. Nevertheless, it is only suitable for those potential earthquake sources delineated along a sing le seismogenic fault. This inhomogeneous model has certain effects on seismic risk assessment, especia ll y for those potential earthquake sources with higher earthquake reoccurrence rat es of the maximum magnitude interval. In general, higher reoccurrence rate of th e maximum magnitude interval and lower exceeding probability level may bring lar ger difference of the results in seismic risk analysis by adopting the inhomogen eous model, the PGA values increase inner the potential earthquake source, but r educe near the vicinity and out of the potential earthquake source. Taking the T angyin potential earthquake source as an example, with exceeding probability of 10% and 2% in 50 years, the difference of the PGA values between inhomogeneous m odel and homogenous models can reach 12%. 展开更多
关键词 Strike-slip fault segment Strong earthquakes Inhomogeneous di stribution Seismic risk assessment
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A MULTIDISCIPLINARY AND INTEGRATED STUDY OF RICE PRECISION FARMING 被引量:2
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作者 XIEGao-di CHENShen-bin +3 位作者 QIWen-hu LUYao YANGXing-wei LIUCheng-liang 《Chinese Geographical Science》 SCIE CSCD 2003年第1期9-14,共6页
In terms of demands of rice farming in the southern China, the information processing system and the yield measurement system that is installed in combine harvester, are designed and completed. Now the systems have be... In terms of demands of rice farming in the southern China, the information processing system and the yield measurement system that is installed in combine harvester, are designed and completed. Now the systems have been used in demonstration site in the Experiment Base of Shanghai Precision Agriculture. Based on the idea of spatial-oriented, object-oriented, user-oriented, the Farm Geographic Information System for precision farming of rice was developed, which is characterized by intelligence and visualized. The Decision-making Management System is integrated with rice growth model, expert model for rice cultivation. The DGPS, RS, GIS and intelligence sensors and computer technique were adopted in building the artificial intelligence system for measuring grain yield that is installed in combine harvester, so the combine harvester could provide the grain yield distribution map real-timely. The environmental and economic assessment shows that the precision rice farming applied in the demonstration site will benefit the society, economy and ecology greatly. 展开更多
关键词 precision fanning RICE technology integration
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Wheel-Individual Estimation of the Friction Potential for Split Friction and Changing Friction Conditions for the Application in an Automated Emergency Braking System 被引量:1
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作者 Cornelia Lex Hans-Ulrich Kobialka Arno Eichberger 《Journal of Energy and Power Engineering》 2014年第6期1153-1158,共6页
Including information of the current road surface conditions can significantly improve the effectiveness of an AEB (automated emergency braking) system to avoid accidents or reduce the injury severity in rear-end cr... Including information of the current road surface conditions can significantly improve the effectiveness of an AEB (automated emergency braking) system to avoid accidents or reduce the injury severity in rear-end crashes. A method to estimate the friction potential based on on-board sensor information is shown in this work. This work expands the scope of existing investigations on whether the accuracy needed for the warning and intervention strategies of AEB can be reached with the proposed method. First, the bandwidth of surface conditions investigated is extended by including low friction surfaces comparable to ice. Second, situations of changing surface conditions and wheel-individual surface conditions were evaluated. Finally, estimation based on different sensor sets was conducted with regard to series application. The investigations are based on measurements performed on a proving ground. The main emphasis was placed on estimation during longitudinal driving conditions. The used sensors include advanced vehicle dynamics measurement equipment as well as standard on-board sensors of the vehicle. 展开更多
关键词 Tire road friction estimation automated emergency braking system recurrent neural networks echo state networks
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船坞船体建造精度管理概谈
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作者 王任意 《广船科技》 2009年第3期8-11,共4页
本文主要介绍船坞建造的油船货舱区分段精度管理实施过程,包括总段余量预修割、全站仪预搭载、大合拢定位三个阶段。
关键词 船坞 船体建造 精度 余量
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Analyses and predictions of rock cuttabilities under different confining stresses and rock properties based on rock indentation tests by conical pick 被引量:10
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作者 Shao-feng WANG Yu TANG +1 位作者 Xi-bing LI Kun DU 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2021年第6期1766-1783,共18页
The rock indentation tests by a conical pick were conducted to investigate the rock cuttability correlated to confining stress conditions and rock strength.Based on the test results,the regression analyses,support vec... The rock indentation tests by a conical pick were conducted to investigate the rock cuttability correlated to confining stress conditions and rock strength.Based on the test results,the regression analyses,support vector machine(SVM)and generalized regression neural network(GRNN)were used to find the relationship among rock cuttability,uniaxial confining stress applied to rock,uniaxial compressive strength(UCS)and tensile strength of rock material.It was found that the regression and SVM-based models can accurately reflect the variation law of rock cuttability,which presented decreases followed by increases with the increase in uniaxial confining stress and the negative correlation to UCS and tensile strength of rock material.Based on prediction models for revealing the optimal stress condition and determining the cutting parameters,the axial boom roadheader with many conical picks mounted was satisfactorily utilized to perform rock cutting in hard phosphate rock around pillar. 展开更多
关键词 rock cuttability rock indentation prediction model regression analysis support vector machine neural network
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A Virtual Erection Simulation System for a Steel Structure Based on 3-D Measurement Data
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作者 Deok Eun Kim Tuo Han Chen 《Journal of Marine Science and Application》 2012年第1期52-58,共7页
he virtual erection simulation system was explained for a steel structure including ship and ocean plant blocks. The simulation system predicted the erection state to optimize any gap or overlap of blocks based on 3-D... he virtual erection simulation system was explained for a steel structure including ship and ocean plant blocks. The simulation system predicted the erection state to optimize any gap or overlap of blocks based on 3-D measurement data. The blocks were modified (cut) on the basis of the simulation result on the ground before erecting them by crane. The re-cutting process was not required and the blocks were erected into a mother ship speedily. Therefore, the erection time is reduced, increasing the dock turnover. 展开更多
关键词 block erection dimensional accuracy control 'of ship block production planning and scheduling ship construction virtual simulation system steel structure
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Error assessment of laser cutting predictions by semi-supervised learning
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作者 Mustafa Zaidi Imran Amin +1 位作者 Ahmad Hussain Nukman Yusoff 《Journal of Central South University》 SCIE EI CAS 2014年第10期3736-3745,共10页
Experimentation data of perspex glass sheet cutting, using CO2 laser, with missing values were modelled with semi-supervised artificial neural networks. Factorial design of experiment was selected for the verification... Experimentation data of perspex glass sheet cutting, using CO2 laser, with missing values were modelled with semi-supervised artificial neural networks. Factorial design of experiment was selected for the verification of orthogonal array based model prediction. It shows improvement in modelling of edge quality and kerf width by applying semi-supervised learning algorithm, based on novel error assessment on simulations. The results are expected to depict better prediction on average by utilizing the systematic randomized techniques to initialize the neural network weights and increase the number of initialization. Missing values handling is difficult with statistical tools and supervised learning techniques; on the other hand, semi-supervised learning generates better results with the smallest datasets even with missing values. 展开更多
关键词 semi-supervised learning training algorithm kerf width edge quality laser cutting process artificial neural network(ANN)
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Research on A Web Intelligent Information Extraction Method
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作者 Zhimin Wang 《International Journal of Technology Management》 2013年第2期94-96,共3页
The paper introduce segmentation ideas in the pretreatment process of web page. By page segmentation technique to extract the accurate information in the extract region, the region was processed to extract according t... The paper introduce segmentation ideas in the pretreatment process of web page. By page segmentation technique to extract the accurate information in the extract region, the region was processed to extract according to the rules of ontology extraction, and ultimately get the information you need. Through experiments on two real datasets and compare with related work, experimental results show that this method can achieve good extraction results. 展开更多
关键词 pages segmentation ONTOLOGY extraction rules accuracy information extraction
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Tracking Target Identification Model Based on Multiple Algorithms
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作者 Ma Ding 《International Journal of Technology Management》 2013年第2期68-72,共5页
In view of current situation of bad data synchronization, image blurring and tracking station stability in tracking target identification, a kind of tracking target identification model based on multiple algorithms wa... In view of current situation of bad data synchronization, image blurring and tracking station stability in tracking target identification, a kind of tracking target identification model based on multiple algorithms was put forward, firstly establishing the image degradation model, using the wavelet algorithm for image preprocessing, doing image edge segmentation by using Robert algorithm after pretreatment, then using the maximum variance threshold method for image threshold segmentation, then extracting target features from the segmented image, and finally using the ABS algorithm to finish target tracking. Experiments proved the proposed model practical and effective. 展开更多
关键词 Robert algorithm image degradation largest variance threshold method ABS algorithm target tracking
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Aeroengine Performance Parameter Prediction Based on Improved Regularization Extreme Learning Machine
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作者 CAO Yuyuan ZHANG Bowen WANG Huawei 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI CSCD 2021年第4期545-559,共15页
Performance parameter prediction technology is the core research content of aeroengine health management,and more and more machine learning algorithms have been applied in the field.Regularized extreme learning machin... Performance parameter prediction technology is the core research content of aeroengine health management,and more and more machine learning algorithms have been applied in the field.Regularized extreme learning machine(RELM)is one of them.However,the regularization parameter determination of RELM consumes computational resources,which makes it unsuitable in the field of aeroengine performance parameter prediction with a large amount of data.This paper uses the forward and backward segmentation(FBS)algorithms to improve the RELM performance,and introduces an adaptive step size determination method and an improved solution mechanism to obtain a new machine learning algorithm.While maintaining good generalization,the new algorithm is not sensitive to regularization parameters,which greatly saves computing resources.The experimental results on the public data sets prove the above conclusions.Finally,the new algorithm is applied to the prediction of aero-engine performance parameters,and the excellent prediction performance is achieved. 展开更多
关键词 extreme learning machine AEROENGINE performance parameter prediction forward and backward segmentation algorithms
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Fingerspelling Recognition by Hand Shape Using Higher-Order Local Auto-Correlation Features
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作者 Yoshihiro Mitani Takuya Kanemura +1 位作者 Yusuke Fujita Yoshihiko Hamamoto 《Computer Technology and Application》 2012年第12期784-788,共5页
The fingerspelling recognition by hand shape is an important step for developing a human-computer interaction system. A method of fingerspelling recognition by hand shape using HLAC (higher-order local auto-correlat... The fingerspelling recognition by hand shape is an important step for developing a human-computer interaction system. A method of fingerspelling recognition by hand shape using HLAC (higher-order local auto-correlation) features is proposed. Furthermore, in order to use HLAC features more effectively, the use of image processing techniques: reducing an image resolution, dividing an image, and image pre-processing techniques, is also proposed. The experimental results show that the proposed method is promising. 展开更多
关键词 Image processing techniques fingerspelling recognition HLAC (higher-order local auto-correlation) features.
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