191 research outputs found

    The Automatic Cell Test Machine Application and Algorithm Research for TFT-LCD Defect Inspection

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    近年来国内汽车消费逐年升温,车载电子设备越来越多样化,液晶屏幕显示技术的应用更多更广。比如车载配备了中小尺寸的中控液晶显示屏,倒车影像系统,抬头显示,后座娱乐,后视镜显示等等。车载液晶显示屏预计2016年将达到每年一亿片的需求量,车载屏幕不仅要求高分辨率,还有耐高温、抗震动的功能,因此,对面板厂商的要求越来越高。依赖人工裸眼判断存在低效率和漏检风险,因此,将自动点灯检查机台导入TFT-LCD品质检测中是确保液晶面板画面品质的必然发展趋势。本文基于厦门友达光电自主开发的CELLTEST检查机台为基础,展开自动点灯检查机在TFT-LCD点灯画面检查应用的研究。 首先本文在分析TFT-LCDJI段...With the gradual increase of automobile consumption in China in recent years, vehicle-mounted electronic equipment has achieved a much wider variety, and the application of LCD screen display technique is also broader, such as small-to –medium-size central-control LCD, Rear Camera Parking Aid, Head-up Display, Rear-seat Entertainment, Rear View Monitor, etc. The demand of vehicle-mounted LCD is ex...学位:工程硕士院系专业:航空航天学院_工程硕士(机械工程)学号:X201118201

    Research on Materialized View Selection

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    定义了数据仓库领域的视图选择问题,并讨论了与该问题相关的代价模型、收益函数、代价计算、约束条件和视图索引等内容;介绍了3大类视图选择方法,即静态方法、动态方法和混合方法,以及各类方法的代表性研究成果;最后展望未来的研究方向.Definition of view selection issue in the field of data warehouses is presented, followed by the discussion of related problems, such as cost model, benefit function, cost computation, restriction condition, view index, etc. Then three categories of view selection methods, namely, static, dynamic and hybrid methods are discussed. For each method, some representative work is introduced. Finally some future trends in this area are discussed.Supported by the National Natural Science Foundation of China under Grant No.60473051 (国家自然科学基金); the National High-Tech Research and Development Plan of China under Grant Nos.2007AA01Z191, 2006AA01Z230 (国家高技术研究发展计划(863)

    Change Data Capture in Real-Time Active Data Warehouses: A Survey

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    本文是在北京大学数据库实验室攻读博士学位期间发表的。实时主动数据仓库是数据仓库的最新发展阶段和未来发展趋势,它为企业提供了对战略决策和战术决策的双重支持.实时主动数据仓库中包含两类数据,即实时数据和非实时数据,相应地,需要两种不同类型的变化数据捕捉方法,即支持实时变化数据捕捉的方法和普通的(不支持实时的)变化数据捕捉方法.结合在该领域的研究经验,对实时主动数据仓库中可以使用的多种变化数据捕捉方法进行了系统地论述,并比较各种方法的应用条件、优点、缺点和适用场合。Real-time active data warehouse is the most recent stage in the evolution history of data warehouses.It supports both strategic decision and tactic decision,which will bring great benefits to organizations.There are two types of data existing in real-time active data warehouses,i.e.,real-time data and non-real-time data.Accordingly,change data capture methods are classified into tWO kinds,including those supporting real-time change data capture and those not supporting real-time change data capture.Based on extensive research work in this field,those change data capture methods are systematically discussed,which may meet the requirements in real-time active data warehouses.国家自然科学基金项目(60473015);国家“863”高技术研究发展计划基金项目(2006AAl2Z217);HP中国实验室联合项

    Research on Requirement-based Real-time Data Integration in Real-time Active Data Warehouses

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    本文是在北京大学数据库实验室攻读博士学位期间发表的。实时数据集成是实时主动数据仓库研究领域的一个重要问题。现有的研究成果都是从技术角度出发,而并没有考虑具体的商务应用需求。而在大型商务应用中,即使采用过滤规则只捕捉感兴趣的变化数据,也会产生大量的数据集成工作,从而导致不必要的沉重系统开销,同时还很有可能出现系统响应缓慢和用户需求无法得到满足等情况。本文从应用角度出发,提出了实时主动数据仓库中面向需求的实时数据集成方法,包括被频繁请求的数据的实时集成、满足突发请求的实时数据集成和由用户决定的实时数据集成。针对不同的商务需求,采用不同的数据集成策略,可以很好地满足不同类型的应用需求。Real-time data integration is a very important aspect in the field of real-time active data warehouse. Almost all the available research work now is from a technological point of view instead of an application angle. While in the real-world business application, a large amount of real-time data integration needs to be done even with the help of change data capture technology to integrate only the interesting part of the data from the data source, which will usually lead to the deteriorated system performance and fail to satisfy the business requirement in some cases. From an application angle, we here propose three requirement-based real-time data integration methods, including: real-time integration for the frequently requested data, real-time integration for the suddenly arising requirement and user-decided real-time integration. By adopting the appropriate method for the specific application occasion, we can better satisfy the various business requirements.国家自然科学基金项目(60473015);国家“863”高技术研究发展计划基金项目(2006AAl2Z217);HP中国实验室联合项

    Materialized Views Selection of Multi-Dimensional Data in Real-Time Active Data Warehouses

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    通过基于主动决策引擎日志的数据挖掘来找到分析规则的CUBE 使用模式,从而为多维数据实视图选择算法提供重要依据;在此基础上设计了3A 概率模型,并给出考虑CUBE 受访概率分布的视图选择贪婪算法PGreedy(probability greedy), 以及结合视图挽留原则的视图动态调整算法. 实验结果表明, 在实时主动数据仓库环境下,PGreedy 算法比BPUS(benefit per unit space)算法具有更好的性能. In this paper, data mining based on the log of active decision engine is introduced to find the CUBE using pattern of analysis rules, which can be used as important reference information for materialized views selection. Based on it, a 3A probability model is designed, and the greedy algorithm, called PGreedy (probability greedy), is proposed, which takes into account the probability distribution of CUBE. Also view keeping rule is adopted to achieve better performance for dynamic view adjusting. Experimental results show that PGreedy algorithm can achieve better performance than BPUS (benefit per unit space) algorithm in real-time active data warehouses environment.Supported by the National Natural Science Foundation of China under Grant No.60473051 (国家自然科学基金); the China HP Co. and Peking University Joint Project (北京大学-惠普(中国)合作项目

    Comparative Study on Characteristics of Urban Rainfall Runoff from Two Urban Lawn Catchments in Macau and Xiamen

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    在澳门与厦门分别选一分流制管道类型的绿地小流域开展降雨径流监测,以研究城市绿地降雨径流污染特征.结果表明,两城市绿地小流域降雨径流的主要污染物为COd、TP、nO3--n,其EMC平均值分别为165.77--60.48 Mg/l、0.96--0.44 Mg/l和7.16--1.18 Mg/l;两城市绿地的COd、TP、nO3--n污染负荷平均值分别为6.53--0.63 kg/HM2、0.037 5--0.004 7 kg/HM2和0.012 2--0.012 8 kg/HM2;绿地降雨径流污染物浓度峰值出现时间早于径流量峰值;城市绿地降雨径流初始冲刷效应不明显,厦门绿地小流域降雨径流COd、TSS、TP及nO3--n的ff30分别为36.26%、26.13%、28.13%和39.03%.基于多元回归分析结果表明,总降雨量和总径流量是影响绿地降雨径流污染初始冲刷效应的主要因素.A comparative study on characteristics of stormwater runoff from two urban lawn catchments in Macau(ELH) and Xiamen(PGH) with separated sewer system were conducted.The result obtained shows that COD,TP and(NO---_3-N) are the major pollutants with mean EMC of 165.77-60.48(mg/L),0.96-0.44(mg/L) and 7.16-1.18(mg/L),respectively,and the mean values of pollutants loads of COD,TP and(NO---_3-N) from study lawn catchments are 6.53-0.63(kg/hm--2),(0.037?5)-(0.004?7)(kg/hm--2) and(0.012?2)-(0.012?8)(kg/hm--2),respectively.Peak values of major pollutant concentrations usually precede the flow peak.First flush effect of rainfall runoff from two study catchments is no obvious,which can be reflected by the low mean value of FF_(30) of TSS,COD,TP and(NO---_3-N),with 36.26%,26.13%,28.13% and 39.03%,respectively.Based on multivariate statistical analysis,first flush effect from urban lawn rainfall runoff is greatly influenced by total rainfall amount(T_r) and total runoff volume(V).国家自然科学基金项目(50778098);福建省青年人才项目(2007F3093

    Effect of Sodium D-Gluconate-Based Inhibitor in Preventing Corrosion of Reinforcing Steel in Simulated Concrete Pore Solutions

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    应用电化学技术,结合扫描电子显微镜(SEM)观测,研究d-葡萄糖酸钠、钼酸钠和硫脲三组分复合缓蚀剂对模拟混凝土孔隙液中钢筋腐蚀行为的影响及其阻锈作用.结果表明:在含3.5%(W)nACl的模拟混凝土孔隙液中,复合缓蚀剂具有协同效应,对钢筋有良好的阻锈作用.当d-葡萄糖酸钠、钼酸钠和硫脲浓度分别为750、250和500Mg·l-1时,对钢筋的缓蚀效率可达到94.5%.应用软硬酸碱(HSAb)理论分析缓蚀机理,可认为三组分复合缓蚀剂在钢筋表面共同形成保护膜而阻止钢筋的腐蚀.The corrosion behavior of reinforcing steel in simulated concrete pore solutions with and without corrosion inhibitors was studied by electrochemical techniques and scanning electron microscopy(SEM).A combined inhibitive effect of sodium D-gluconate,Na2MoO4 and thiourea on restraining the corrosion of reinforcing steel immersed in the solution was observed.This result showed that there was a synergetic effect among the three agents in corrosion prevention.After adding the compound inhibitor(750 mg · L-1 sodium D-gluconate,250 mg · L-1 Na2MoO4,500 mg · L-1 thiourea) into the simulated concrete pore solution containing 3.5%(w) NaCl,the inhibition efficiency of the compound inhibitor was 94.5%.According to the Hard and soft acids and bases(HSAB) theory,the compound inhibitor worked by forming a protective film on the steel surface.国家自然科学基金(21073151;21173177;50731004;21021002)资助项---

    Dealing with Query Contention Issue in Real-time Data Warehouses by Dynamic Multi-level Caches

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    The issue of query contention and scalability is the most difcult issue facing organizations deploying real-time data warehouse s olutions. The contention between complex se-lects and continuous inserts tends to severely limit the scal-ability of the data warehouses. I n this paper, we present a new method called dynamic multi-level caches, to effec-tively deal with the problem of query contention and scal-ability in real-time data warehouses. We differentiate be-tween queries with various data freshness requirements, and use multi-level caches to satisfy these different require-ments. Every query arriving at the system will be automat-ically redirected to the corresponding cache to access the required data, which means that the query loads are dis-tributed to multi-level caches instead of becoming blocked in the only one cache due to the contention between query and update operations. Extensive experiments on s everal real datasets s how that our method can effectively balance the query loads among multi-level caches and achieve desirable system performance

    User-oriented Materialized View Selection

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    The problem of materialized view selection has been long researched, and many approaches have been proposed to deal with this issue. However, all the methods proposed to date strive toward improving the overall query performance, instead of being user-oriented. In this paper, we propose a new user-oriented method, called SOMES (uSerOriented Materialized viEw Selection), aiming at achieving better performance for view selection problem. SOMES takes into account query characteristics of different users, in which, users are classified into different groups according to their query characteristics, and various user groups are provided with their own windows, user view windows containing the views involved in their own query process. Experimental results show that our method can achieve desirable performance improvements over other methods such as BPUS and FPUS

    An ecological study on zooplankton in the northern Beibu Gulf V: the effects of microzooplankton grazing on phytoplankton in summer

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    2011年8月份于北部湾北部海域5个观测站位获得的分层水样,分析了表层叶绿素A含量和表层微型浮游动物丰度以及类群组成;同时于现场采用稀释培养法研究了该海域浮游植物生长率(μ)和微型浮游动物的摄食率(g)。分析和测定结果表明:调查海区的微型浮游动物丰度400—1167个/l,类群组成以无壳纤毛虫为主;浮游植物的生长率为-1.50—1.13 d-1,微型浮游动物摄食率为0.33—1.08 d-1;推算微型浮游动物对浮游植物现存量以及初级生产力的摄食压力分别为28.1%—66.0%和-7.4%—438.4%。相对于中国其他海区,8月份北部湾北部海域微型浮游动物摄食速率处于中等水平。调查期间,广西沿海高生产力海区,浮游植物生长率大于微型浮游动物动物的摄食率,浮游植物生物量处于积累期;涠洲岛以南海域,浮游植物生产力较低,微型浮游动物摄食作用是控制浮游植物生长的重要因素。In August 2011,we quantified the impact of microzooplankton grazing on phytoplankton production in the surface waters of the northern Beibu Gulf,Vietnam.Shipboard dilution incubation experiments were carried out at five stations to calculate phytoplankton specific growth rates and the specific rates of grazing losses to microzooplankton.Dilution experiments using chlorophyll a( Chl a) as a tracer were used to estimate daily rates in two size fractions; image-analyzed microscopy provided quantitative estimates of microzooplankton standing stock( including ciliate and vertebrate larvae).PFW( particle-free water) was used to dilute seawater to five target dilutions of 0%,20%,40%,60%,and 80%.Microzooplankton grazing and phytoplankton growth rates were estimated by the linear regression of AGR( apparent growth rate) versus dilution factor.We estimated the grazing impact of microzooplankton on phytoplankton by calculating the percentage of phytoplankton standing stock and potential primary production ingested.Average total chlorophyll a concentration was( 0.67 ± 0.58) μg / L.Small-celled phytoplankton dominated this particular community.A notable characteristic of the phytoplankton community structure was that nano- and picoplankton made up a significant portion.Aloricate ciliates dominated the microzooplankton samples,in particular Strombidium,which accounted for 27.2% of total aloricate ciliate abundance.In addition,loricate ciliates and copepod nauplii were recorded.Microzooplankton densityvaried from 400 to 1167 ind / L.The horizontal distribution of microzooplankton was greater in nearshore than in offshore waters.Abundance did not differ significantly with chlorophyll a concentration in this study; however,there was a positive correlation between microzooplankton abundance and temperature.The phytoplankton growth rate( < 200 μm) ranged between-1.50 and 1.13 d-1,with the highest values being associated with nearshore waters.Meanwhile phytoplankton mortality due to microzooplankton grazing( 0.33—1.08 d-1) was highest at the same nearshore sites; however,growth rates were low at these sites.Consequently,microzooplankton consumed 28.1%—66.0% of chlorophyll a standing stocks and-8.1%—438.4% of the primary production per day.However,the grazing rate of microzooplankton on nanoplankton( 2— 20 μm) varied from 1.87 to 0.52 d-1,with an average of( 0.94±0.57) d-1.Given that the rates of grazing on phytoplankton of <200 μm were lower than those on nanoplankton,we conclude that microzooplankton prefer to graze on nanoplankton.There was a positive correlation between phytoplankton growth rate and grazing rate; in addition,significant differences between grazing rate and chlorophyll a were found.This suggests that microzooplankton grazing activity is the main factor regulating the community structure and restraining the growth of phytoplankton.During the investigation period, microzooplankton grazing effectively controlled the growth of phytoplankton,consuming 176.2% of primary production on average.When grazing rates are far greater than phytoplankton growth rates,energy is transferred from lower to higher trophic levels more effectively.In the surface waters of the northern Beibu Gulf,microzooplankton largely control the growth of phytoplankton by grazing offshore rather than in nearshore waters where primary production is high.The growth and grazing rates combined promote planktonic ecosystem stability in this area.These results indicate that grazing by microzooplankton is a key process controlling the growth of phytoplankton in this area.海湾公益项目(201005012
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