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121.
Automated currency validation requires a decision to be made regarding the authenticity of a banknote presented to the validation system. This decision often has to be made with little or no information regarding the characteristics of possible counterfeits as is the case for issues of new currency. A method for automated currency validation is presented which segments the whole banknote into different regions, builds individual classifiers on each region and then combines a small subset of the region specific classifiers to provide an overall decision. The segmentation and combination of region specific classifiers to provide optimized false positive and false negative rates is achieved by employing a genetic algorithm. Experiments based on high value notes of Sterling currency were carried out to assess the effectiveness of the proposed solution.  相似文献   
122.
基于DSP的电力数据采集平台的设计与研究   总被引:1,自引:0,他引:1  
介绍了一种用于电力系统的数据采集系统.该系统采用数字信号处理器(DSP)和复杂可编程逻辑器件(CPLD)作为核心芯片,给出了主要部分的电路及其原理、功能,系统中使用CPLD实现基本逻辑,使系统有足够的冗余和灵活性,具有可靠性高、可升级等优点.  相似文献   
123.
李超  陈丹伟  李军 《电子工程师》2004,30(11):33-36
Parlay X是一套简单易懂、比之Parlay在更高层次抽象电信网络基本功能的应用编程接口(API),它以Web Service的形式供IT应用开发者在开发的应用中调用电信网络功能.下一代网络业务的发展是一个渐进过程,对运营商来说,如何以更小的成本快速开发和部署新业务成了当务之急.文中介绍了Parlay X体系结构模型,着重提出了基于Parlay X的电信增值业务过渡模型,并对短信业务的开发流程进行了分析.  相似文献   
124.
Yao  Chuang  Zhangxi 《Computer Communications》2006,29(18):3946-3956
In this paper, a general fluid model is developed to study the performance and fairness of BitTorrent-like networks. The fluid model incorporates two important features previously isolated from system performance models, user settings with multiple groups and inter-group data exchange induced by the choking algorithm. Our numerical results point out some key parameters of performance, such as the staying time of seeders. Generally, selfish behavior does not receive equal performance degradation, and in some scenarios users have strong incentives of free-riding. We also find content delivery can be greatly deterred when malicious free-riders are overwhelming.  相似文献   
125.
李超  刘元果 《计算机工程》2003,29(16):69-70,132
首先对DTD和CSS的语法规则进行了简单介绍,然后给出了一个对DTD和CSS进行语法分析和编辑的设计思路,最后给出了编辑器的实现效果以及对下一步工作的展望。  相似文献   
126.
In this report, we describe the nature of intermediate order in silicon as determined by recent measurements on thin films using transmission electron microscopy (TEM) and Raman scattering. The TEM images show in addition to the expected continuous random network (CRN), the presence of highly ordered quasi-one-dimensional “chain-like objects” (CLO's) that are 1–2 nm wide and tens of nm long that meander and show some evidence of cross-linking with each other. The presence of these objects correlate to a Raman feature centered at 490 cm−1 whose width is 35–40 cm−1, and is used to quantify the heterogeneity in terms of the CLO and CRN (=475 cm−1 scattering) concentrations. The 490 and 35 cm−1 values are consistent with bond angle deviations approaching 0°, and thus reinforces an association with the CLOs. We find that in reference quality a-Si:H (made using pure SiH4), the CLO concentration is about 5 vol%, while in state-of-the-art material using high H2 levels of dilution during processing, it increases to about 15%. Increased stability of such material to light-soaking is thus not mediated by a direct volumetric replacement of poor with high-quality components. Rather, an important characteristic of intermediate order in silicon is the low-dimensional aspect of its order, which allows it to influence more total volume than which it is itself composed. Consistent with these and other recent findings, we propose a tensegrity model of amorphous silicon.  相似文献   
127.
The continuous reduction of chip size driven by the market demand has a significant impact on circuit design and assembly process of IC packages. Shrinking chip size and increasing I/O counts require finer bond pad pitch and bond pad size for circuitry layout. As a result, serious wire deflection during transfer molding process could make adjacent wires short, and this issue becomes more critical as a smaller wire diameter has to be applied for the finer pitch wire bonded IC devices.This paper presents a new encapsulation process development for 50 μm fine pitch plastic ball grid array package. Since reduced wire diameter decreases the bending strength of bonded wires significantly, wire deflection during molding process becomes quite serious and critical. Experiments on conventional transfer molding were conducted to evaluate wire span threshold with 23.0 μm diameter gold wire. The results show that the wire span threshold is about 4.1 mm, which is much shorter than the wire span threshold of over 5.0 mm for wire with 25.4 μm diameter. Finite element analysis shows there is a significant difference in the wire deflection between 23.0 μm gold wire and 25.4 μm gold wire diameter under the same action of mold flow. A novel encapsulation method is introduced using non-sweep solution. The wire span could be extended to over 5.0 mm with wire sweep less than 1%. Reliability tests conducted showed that all the units passed 1000 temperature cycles (−55 to 125 °C) with JEDEC moisture sensitivity level 2a (60 °C/60% relative humidity for 120 h) and 3 times reflow (peak temperature at 220–225 °C). It is believed that this solution could efficiently overcome the risk of wire short issues and improve the yield of ultra fine pitch wire bonds in high-volume production.  相似文献   
128.
川东地区井下套管损坏的原因分析及对策   总被引:4,自引:0,他引:4  
姚振华 《钻采工艺》1998,21(2):11-12,32
本文就近年来在钻井施工中遇到的4口井发套管损坏的问题进行了原因分析,提出了防止井下套管损坏对策。  相似文献   
129.
本文围绕冶金企业节能管理的工作内容和要求,论述了企业节能员应掌握的技术和提高技术途径。  相似文献   
130.
The effect of phenylephrine-induced reflex parasympathetic stimulation on QT interval and its dispersion was studied in 16 healthy subjects with a history of paroxysmal supraventricular tachycardia, both during sinus rhythm and during atrial pacing. Results demonstrate that rapid reflex parasympathetic stimulation does not influence QT interval duration or QT dispersion, and also emphasize the inappropriateness of Bazett's formula, the need for comparison of QT intervals during identical heart rates, and the importance of analyzing all 12 leads of a standard electrocardiogram when assessing the effects of various interventions on the QT interval.  相似文献   
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