数字信号处理
一、导论
数字信号处理（DSP）是由一系列的数字或符号来表示这些信号的处理的过程的。数字信号处理与模拟信号处理属于信号处理领域。DSP包括子域的音频和语音信号处理，雷达和声纳信号处理，传感器阵列处理，谱估计，统计信号处理，数字图像处理，通信信号处理，生物医学信号处理，地震数据处理等。
由于DSP的目标通常是对连续的真实世界的模拟信号进行测量或滤波，第一步通常是通过使用一个模拟到数字的转换器将信号从模拟信号转化到数字信号。通常，所需的输出信号却是一个模拟输出信号，因此这就需要一个数字到模拟的转换器。即使这个过程比模拟处理更复杂的和而且具有离散值，由于数字信号处理的错误检测和校正不易受噪声影响，它的稳定性使得它优于许多模拟信号处理的应用（虽然不是全部）。
DSP算法一直是运行在标准的计算机，被称为数字信号处理器（DSP）的专用处理器或在专用硬件如特殊应用集成电路（ASIC）。目前有用于数字信号处理的附加技术包括更强大的通用微处理器，现场可编程门阵列（FPGA），数字信号控制器（大多为工业应用，如电机控制）和流处理器和其他相关技术。
在数字信号处理过程中，工程师通常研究数字信号的以下领域：时间域（一维信号），空间域（多维信号），频率域，域和小波域的自相关。他们选择在哪个领域过程中的一个信号，做一个明智的猜测（或通过尝试不同的可能性）作为该域的最佳代表的信号的本质特征。从测量装置对样品序列产生一个时间或空间域表示，而离散傅立叶变换产生的频谱的频率域信息。自相关的定义是互相关的信号本身在不同时间间隔的时间或空间的相关情况。
二、信号采样
随着计算机的应用越来越多地使用，数字信号处理的需要也增加了。为了在计算机上使用一个模拟信号的计算机，它上面必须使用模拟到数字的转换器（ADC）使其数字化。采样通常分两阶段进行，离散化和量化。在离散化阶段，信号的空间被划分成等价类和量化是通过一组有限的具有代表性的信号值来代替信号近似值。
奈奎斯特-香农采样定理指出，如果样本的取样频率大于两倍的信号的最高频率，一个信号可以准确地重建它的样本。在实践中，采样频率往往大大超过所需的带宽的两倍。
数字模拟转换器（DAC）用于将数字信号转化到模拟信号。数字计算机的使用是数字控制系统中的一个关键因素。
三、时间域和空间域
在时间或空间域中最常见的处理方法是对输入信号进行一种称为滤波的操作。滤波通常包括对一些周边样本的输入或输出信号电流采样进行一些改造。现在有各种不同的方法来表征的滤波器，例如：
一个线性滤波器的输入样本的线性变换；其他的过滤器都是“非线性”。线性滤波器满足叠加条件，即如果一个输入不同的信号的加权线性组合，输出的是一个同样加权线性组合所对应的输出信号。
“因果”滤波器只使用以前的样本的输入或输出信号；而“非因果”滤波器使用未来的输入样本。一个非因果滤波器通常可以通过增加一个延迟将它变成了一个因果滤波器。
“时间不变”滤波器随着时间的推移性具有稳定特性；其他滤波器如随时间变化的自适应滤波器。
一些滤波器是“稳定”的，别的是“不稳定的”。一个稳定的滤波器产生的输出信号随时间收敛于一个恒定值，或在一个有限的时间间隔内是有界的。一种不稳定的滤波器可以产生一个没有增长界限的输出，甚至零输入有界。
“有限脉冲响应（FIR）”滤波器只使用于输入信号，而“无限脉冲响应滤波器（IIR）”使用于输入信号和输出信号之前的样品。FIR滤波器总是稳定的，而IIR滤波器可能是不稳定的。
大多数滤波器可以被描述在z域（频域的一个超集）的传递函数。如果它是一个FIR滤波器的脉冲响应和阶跃响应，滤波器也可以被描述为一个差分方程，或对零点和极点的收集。一个FIR滤波器的输出是通过对任何给定的输入与脉冲响应的卷积计算得到的。滤波器也可以被用来推导出一个样品的处理算法的方块图利用硬件指令实现滤波器所代表。
四、频域
信号通常是通过傅立叶变换将其从时间或空间域转换到频率域。傅里叶变换将信号转换信息和相位分量级的每个频率。通常的傅里叶变换转换为功率谱，这是大小的每个频率分量的平方。
在频域对信号分析的最常见的用途是信号特性分析。工程师可以研究频谱来确定哪一频率的存在于输入信号中。
滤波，特别是在非实时的工作也可以被转换到频域实现，应用滤波器，然后转换回时域。这是一个快速，O（nlogn）操作，可以基本上给出任何滤波器的形状包括砖墙滤波器优良的逼近。
有一些常用的频域变换。例如，倒谱转换信号的频域傅立叶变换，取对数，然后将另一个傅里叶变换。这强调的频率成分的幅度较小而保留的频率分量的大小顺序。频域分析又称谱或谱分析。
五、信号处理
信号通常需要以不同的方式进行处理。例如，从一个传感器的输出信号可能被污染的多余电“噪音”。电极连接到一个病人的胸部时，心电图是测量由心脏和其他肌肉的活动引起的微小的电压变化。由于电的干扰从电源的强烈影响，信号通常是采用“总管拾取”。处理信号的滤波电路可以消除或至少降低信号的不需要的部分。现在，越来越多的的情况下，是由DSP技术来进行信号的滤波以提高信号质量或提取重要信息，而不是模拟电子技术。
六、DSP的发展
数字信号处理的发展从1960年代的大型数字计算机的数字运算应用程序的使用快速傅立叶变换（FFT），它允许一个信号的频谱可以快速计算。这些技术在当时没有被广泛使用，因为合适的计算设备通常仅在大学及其他科研机构可以使用。
七、数字信号处理器（DSP）
在20世纪70年代末和20世纪80年代初微处理机的介绍使DSP技术在更广泛的范围内得到了使用。然而，通用微处理器如Intel x86的家庭并不适合于DSP的计算密集型的需求，随着20世纪80年代DSP重要性的增加导致几个主要的电子产品制造商（如德克萨斯仪器，模拟设备和摩托罗拉）去开发数字信号处理器芯片，专门的微处理器，专门设计用于在数字信号处理要求的操作的类型的架构。（注意，缩写DSP数字信号处理的不同的意思，这个词用于处理数字信号，多种技术或数字信号处理器，一种特殊类型的微处理器芯片）。像一个通用微处理器，DSP是一种具有其自己的本地指令代码的可编程器件。DSP芯片是能够每秒进行数以百万计的浮点运算，像他们同类型的更著名的通用器件，更快和更强大的版本正在不断被引入。DSP也可以嵌入在复杂的“系统芯片”装置，通常包括模拟和数字电路。
8、数字信号处理器的应用
DSP技术是当今普遍在手机，多媒体计算机，录像机，CD播放器，硬盘驱动器和控制器的调制解调器等设备，并将很快在电视和电话业务中取代模拟电路。DSP的一个重要的应用是信号的压缩和解压。信号压缩用于数字蜂窝电话，在每一个地方的“单元”让更多的电话同时被处理。DSP信号压缩技术不仅使人们可以相互交谈，而且可以通过使用安装在计算机上的小的摄像机使人们通过显示器看见对方，而这些只需要将传统的电话线连接在一起。在音频CD系统，DSP技术来执行复杂的错误检测和校正原始数据，因为它是从光盘读取。
虽然一些潜在的DSP技术的数学理论，如傅立叶和希尔伯特变换，数字滤波器的设计和信号压缩，可以相当复杂，而数值运算所需的实际实现这些技术是非常简单的，主要包括操作可以在一个便宜的四功能的计算器上进行操作。一种DSP芯片的结构设计进行这样的操作非常快，处理的样品每秒数以亿计，提供实时的性能：即，能够处理一个实时的信号，因为它是采样，然后输出信号的处理，例如扬声器或视频显示。所有的DSP应用前面提到的实例，如硬盘驱动器和移动电话，要求实时操作。
主要电子产品制造商已投入巨资在DSP技术。因为他们现在发现在大众市场的产品应用中，DSP芯片的电子装置占有世界市场的很大比例。销售额每年数十亿美元，并可能继续快速增长。
DSP主要应用的音频信号处理，音频压缩，数字图像处理，视频压缩，语音处理，语音识别，数字通信，雷达，声纳，地震，和生物医学。具体的例子是在数字移动电话的语音压缩与传输，空间匹配均衡的音响、扩声领域，良好的天气预测，经济预测，地震数据处理，和工业过程控制分析，计算机生成的动画电影中，医学影像如CAT扫描和MRI，MP3压缩，图像处理，高保真度扬声器分频器和均衡，并与电吉他放大器使用的音频效果。
九、数字信号处理的实验
数字信号处理是经常使用专门的微处理器，如dsp56000，TMS320，或SHARC。这些通常处理数据使用定点运算，虽然某些版本可以使用浮点算法和更强大。更快的应用FPGA可能从慢启动流处理器应用Freescale公司的出现，传统的较慢的处理器如单片机可能是适当的。
【英文原文】
Digital Signal Processing
1、Introduction
Digital signal processing (DSP) is concerned with the representation of the signals by a sequence of numbers or symbols and the processing of these signals. Digital signal processing and analog signal processing are subfields of signal processing. DSP includes subfields like audio and speech signal processing, sonar and radar signal processing, sensor array processing, spectral estimation, statistical signal processing, digital image processing, signal processing for communications, biomedical signal processing, seismic data processing, etc.
Since the goal of DSP is usually to measure or filter continuous real-world analog signals, the first step is usually to convert the signal from an analog to a digital form, by using an analog to digital converter. Often, the required output signal is another analog output signal, which requires a digital to analog converter. Even if this process is more complex than analog processing and has a discrete value range, the stability of digital signal processing thanks to error detection and correction and being less vulnerable to noise makes it advantageous over analog signal processing for many, though not all, applications.
DSP algorithms have long been run on standard computers, on specialized processors called digital signal processors (DSP)s, or on purpose-built hardware such as application-specific integrated circuit (ASICs). Today there are additional technologies used for digital signal processing including more powerful general purpose microprocessors, field-programmable gate arrays (FPGAs), digital signal controllers (mostly for industrial applications such as motor control), and stream processors, among others.
In DSP, engineers usually study digital signals in one of the following domains: time domain (one-dimensional signals), spatial domain (multidimensional signals), frequency domain, autocorrelation domain, and wavelet domains. They choose the domain in which to process a signal by making an informed guess (or by trying different possibilities) as to which domain best represents the essential characteristics of the signal. A sequence of samples from a measuring device produces a time or spatial domain representation, whereas a discrete Fourier transform produces the frequency domain information that is the frequency spectrum. Autocorrelation is defined as the cross-correlation of the signal with itself over varying intervals of time or space.
2、Signal Sampling
With the increasing use of computers the usage of and need for digital signal processing has increased. In order to use an analog signal on a computer it must be digitized with an analog to digital converter (ADC). Sampling is usually carried out in two stages, discretization and quantization. In the discretization stage, the space of signals is partitioned into equivalence classes and quantization is carried out by replace the signal with representative signal values are approximated by values from a finite set.
The Nyquist-Shannon sampling theorem states that a signal can be exactly reconstructed from its samples if the samples if the sampling frequency is greater than twice the highest frequency of the signal. In practice, the sampling frequency is often significantly more than twice the required bandwidth.
A digital to analog converter (DAC) is used to convert the digital signal back to analog signal.
The use of a digital computer is a key ingredient in digital control systems.
3 、Time and Space Domains
The most common processing approach in the time or space domain is enhancement of the input signal through a method called filtering. Filtering generally consists of some transformation of a number of surrounding samples around the current sample of the input or output signal. There are various ways to characterize filters, for example: A “linear” filter is a linear transformation of input samples; other filters are “non-linear.” Linear filters satisfy the superposition condition, i.e. if an input is a weighted linear combination of different signals, the output is an equally weighted linear combination of the corresponding output signals.
A “causal”filter uses only previous samples of the input or output signals; while a “non-causal”filter uses future input samples. A non-causal filter can usually be changed into a causal filter by adding a delay to it.
A “time-invariant”filter has constant properties over time; other filters such as adaptive filters change in time.
Some filters are “stable”, others are “unstable”. A stable filter produces an output that converges to a constant value with time, or remains bounded within a finite interval. An converges to a constant value with time, or remains bounded within a finite interval. An unstable filter can produce an output that grows without bounds, with bounded or even zero input.
A “Finite Impulse Response”(FIR) filter uses only the input signal, while an “Infinite Impulse Response” filter (IIR) uses both the input signal and previous samples of the output signal. FIR filters are always stable, while IIR filters may be unstable.
Most filters can be described in Z-domain (a superset of the frequency domain) by their transfer functions. A filter may also be described as a difference equation, a collection of zeroes and poles or, if it is an FIR filter, an impulse response or step response. The output of an FIR filter to any given input may be calculated by convolving the input signal with the impulse response. Filters can also be represented by block diagrams which can then be used to derive a sample processing algorithm to implement the filter using hardware instructions.
4、Frequency Domain
Signals are converted from time or space domain to the frequency domain usually through the Fourier transform. The Fourier transform converts the signal information to a magnitude and phase component of each frequency. Often the Fourier transform is converted to the power spectrum, which is the magnitude of each frequency component squared.
The most common purpose for analysis of signals in the frequency domain is analysis of signal properties. The engineer can study the spectrum to determine which frequencies are present in the input signal and which are missing.
Filtering, particularly in non real-time work can also be achieved by converting to the frequency domain, applying the filter and then converting back to the time domain. This is a fast, O (n log n) operation, and can give essentially any filter shape including excellent approximations to brickwall filters.
There are some commonly used frequency domain transformations. For example, the cepstrum converts a signal to the frequency domain Fourier transform, takes the logarithm, then applies another Fourier transform. This emphasizes the frequency components with smaller magnitude while retaining the order of magnitudes of frequency components. Frequency domain analysis is also called spectrum or spectral analysis.
5、Signal Processing
Signals commonly need to be processed in a variety of ways. For example, the output signal from a transducer may well be contaminated with unwanted electrical “noise”. The electrodes attached to a patient’s chest when an ECG is taken measure tiny electrical voltage changes due to the activity of the heart and other muscles. The signal is often strongly affected by “mains pickup”due to electrical interference from the mains supply. Processing the signal using a filter circuit can remove or at least reduce the unwanted part of the signal. Increasingly nowadays, the filtering of signals to improve signal quality or to extract important information is done by DSP techniques rather than by analog electronics.
6、Development of DSP
The development of digital signal processing dates from the 1960’s with the use of mainframe digital computers number-crunching applications such an the Fast Fourier Transform (FFT), which allows the frequency spectrum of a signal to be computed rapidly. These techniques are not widely used at that time, because suitable computing equipment was generally available only in universities and other scientific research institutions.
7、Digital Signal Processors (DSPs)
The introduction of the microprocessor in the late 1970’s and early 1980’s made it possible for DSP techniques to be used in a much wider range of applications. However, general-purpose microprocessors such as the Inter x86 family are not ideally suited to the numerically-intensive requirements of DSP, and during the 1980’s the increasing importance of DSP led several major electronics manufacturers (such as Texas Instruments, Analog Devices and Motorola) to develop Digital Signal Processor chips-specialised microprocessors with architectures designed specifically for the types of operations required in digital signal processing.(Note that the acronym DSP can variously mean Digital Signal Processing, the term used for a wide range of techniques for processing signals digitally, or Digital Signal Processor, a specialized type of microprocessor chip). Like a general-purpose microprocessor, a DSP is a programmable device, with its own native instruction code. DSP chip are capable of carrying out millions of floating point operations per second, and like their better-known general-purpose cousins, faster and more powerful versions are continually being introduced. DSPs can also be embedded within complex “system-on-chip” devices, often containing both analog and digital circuitry.
8、Applications of DSP
DSP technology is nowadays commonplace in such devices as mobile phones, multimedia computers, video recorders, CD players, hard disc drive controllers and modems, and will soon replace analog circuitry in TV sets and telephones. An important application of DSP is in signal compression and decompression. Signal compression is used in digital cellular phones to allow a greater number of calls to be handled simultaneously within each local “cell”. DSP signal compression technology allows people not only to talk to one another but also to see one anther on their computer screens, using small video cameras mounted on the computer monitors, with only a conventional telephone line linking them together. In audio CD systems, DSP technology is used to perform complex error detection and correction on the raw data as it is read from the CD.
Although some of the mathematical theory underlying DSP techniques, such as Fourier and Hilbert transforms, digital filter design and signal compression, can be fairly complex, the numerical operations required actually to implement these techniques are very simple, consisting mainly of operations that could be done on a cheap four-function calculator. The architecture of a
DSP chip is designed to carry out such operations incredibly fast, processing hundreds of millions of samples every second, to provided real-time performance: that is , the ability to process a signal “live” as it is sampled and then output the processed signal, for example to a loudspeaker or video display. All of the practical examples of DSP applications mentioned earlier, such as hard disc drives and mobile phones, demand real-time operation.
The major electronics manufacturers have invested heavily in DSP technology. Because they now find application in mass-market products, DSP chips account for a substantial proportion of the world market for electronic devices. Sales amount to billions of dollars annually, and seem likely to continue to increase rapidly.
The main applications of DSP are audio signal processing, audio compression, digital image processing, video compression, speech processing, speech recognition, digital communications, RADAR, SONAR, seismology, and biomedicine. Specific examples are speech compression and transmission in digital mobile phones, room matching equalization of sound in hi-fi and sound reinforcement applications, weather forecasting, economic forecasting, seismic data processing, analysis and control of industrial processes, computer-generated animations in movies, medical imaging such as CAT scans and MRI, MP3 compression, image manipulation, high fidelity loudspeaker crossovers and equalization, and audio effects for use with electric guitar amplifiers.
9、Implementation
Digital signal processing is often implemented using specialized microprocessors such as the DSP56000, the TMS320, or the SHARC. These often process data using fixed-point arithmetic, although some versions are available which use floating point arithmetic and are more powerful. For faster applications FPGAs might be emerge from companies including Freescale and startup Stream Processors Inc. For slow applications, a traditional slower processor such as a microcontroller may be adequate.
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附录A Lathe fixture design and analysis Ma Feiyue (School of Mechanical Engineering, Hefei, Anhui Hefei 230022, China) Abstract: From the start the main types of lathe fixture, fixture on the flower disc and angle iron clamp lathe was introduced, and on the basis of analysis of a lathe fixture design points. Keywords: lathe fixture; design; points Lathe for machining parts on the rotating surface, such as the outer cylinder, inner cylinder and so on. Parts in the processing, the fixture can be installed in the lathe with rotary machine with main primary uranium movement. However, in order to expand the use of lathe, the work piece can also be installed in the lathe of the pallet, tool mounted on the spindle. THE MAIN TYPES OF LATHE FIXTURE Installed on the lathe spindle on the lathe fixture
广东工业大学华立学院 本科毕业设计（论文） 外文参考文献译文及原文 系部经济学部 专业经济学 年级 2007级 班级名称 07经济学6班 学号 16020706001 学生姓名张瑜琴 指导教师陈锶 2011 年05月
目录 1挑战：小额贷款中的进入和商业银行的长期承诺 (1) 2什么商业银行带给小额贷款和什么把他们留在外 (2) 3 商业银行的四个模型进入小额贷款之内 (4) 3.1内在的单位 (4) 3.2财务子公司 (5) 3.3策略的同盟 (5) 3.4服务公司模型 (6) 4 合法的形式和操作的结构比较 (8) 5 服务的个案研究公司模型：厄瓜多尔和Haiti5 (9)
1 挑战：小额贷款中的进入和商业银行的长期承诺 商业银行已经是逐渐重要的运动员在拉丁美洲中的小额贷款服务的发展2到小额贷款市场是小额贷款的好消息客户因为银行能提供他们一完整类型的财务的服务，包括信用，储蓄和以费用为基础的服务。整体而言，它也对小额贷款重要，因为与他们广泛的身体、财务的和人类。如果商业银行变成重的运动员在小额贷款，他们能提供非常强烈的竞争到传统的小额贷款机构。资源，银行能廉宜地发射而且扩张小额贷款服务rela tively。如果商业广告银行在小额贷款中成为严重的运动员，他们能提出非常强烈的竞争给传统的小额贷款机构。然而，小额贷款社区里面有知觉哪一商业银行进入进入小额贷款将会是短命或浅的。举例来说，有知觉哪一商业银行首先可能不搬进小额贷款因为时候建立小额贷款操作到一个有利润的水平超过银行的标准投资时间地平线。或，在进入小额贷款，银行之后可能移动在－上面藉由增加贷款数量销售取利润最大值－或者更坏的事，退出如果他们是不满意与小额贷款的收益性的水平。这些知觉已经被特性加燃料商业银行的情形进入小额贷款和后来的出口之内。在最极端的，一些开业者已经甚至宣布，”降低尺度死！”而且抛弃了与主意合作的商业银行。 在最 signific 看得到的地方，蚂蚁利益商业银行可能带给小额贷款，国际的ACCION 发展发射而且扩张的和一些商业银行的关系小额贷款操作。在这些情形的大部分方面， ACCION 和它的合伙人正在使用方法，已知的当做服务公司模型，表演早答应当做一个能工作的方法克服真正的。 商业银行的障碍进入和穿越建立长命的小额贷款操作一个商业银行 这论文描述如何服务公司模型、住址商业银行中的主要议题进入进小额贷款，监定成功建立的因素动作井小额贷款服务公司，和礼物结果和小额贷款的课servic e 公司用最长的经验，在海地和审判官席 del 的 SOGEBANK│ SOGESOL 初期结果指出那这服务公司模型表现一重要的突破在促成商业银行进入和留在小额贷款。在厄瓜多尔的 Pichincha│ CREDIFE。初期结果指出服务公司模型在促成商业广告中表现一次重要的突破银行进入而且留在小额贷款。
at89c52单片机简介 中英文资料对照外文翻译文献综述 A T89C52 Single-chip microprocessor introduction Selection of Single-chip microprocessor 1. Development of Single-chip microprocessor The main component part of Single-chip microprocessor as a result of by such centralize to be living to obtain on the chip，In immediate future middle processor CPU。Storage RAM immediately﹑memoy read ROM﹑Interrupt system、Timer /'s counter along with I/O's rim electric circuit awaits the main microcomputer section，The lumping is living on the chip。Although the Single-chip microprocessor r is only a chip，Yet through makes up and the meritorous service be able to on sees，It had haveed the calculating machine system property，calling it for this reason act as Single-chip microprocessor r minisize calculating machine SCMS and abbreviate the Single-chip microprocessor。 1976Year the Inter corporation put out 8 MCS－48Set Single-chip microprocessor computer，After being living more than 20 years time in development that obtain continuously and wide-ranging application。1980Year that corporation put out high performance MCS －51Set Single-chip microprocessor。This type of Single-chip microprocessor meritorous service capacity、The addressing range wholly than early phase lift somewhat，Use also comparatively far more at the moment。1982Year that corporation put out the taller 16 Single-chip microprocessor MCS of performance once
1. Introduction America is one of the countries that speak English. Because of the special North American culture, developing history and the social environment, American English has formed its certain unique forms and the meaning. Then it turned into American English that has the special features of the United States. American English which sometimes also called United English or U.S English is the form of the English language that used widely in the United States .As the rapid development of American economy, and its steady position and strong power in the world, American English has become more and more widely used. As in 2005, more than two-thirds of English native speakers use various forms of American English. The philologists of the United States had divided the English of the United States into four major types: “America n creating”; “Old words given the new meaning”; “Words that eliminated by English”;“The phonetic foreign phrases and the languages that are not from the English immigrates”[1]. Compared to the other languages, American English is much simple on word spelling, usage and grammar, and it is one of the reasons that American English is so popular in the world. The thesis analyzes the differences between American English and British English. With the main part, it deals with the development of American English, its peculiarities compared to that of British English, its causes and tendency. 2. Analyses the Differences As we English learners, when we learning English in our junior or senior school, we already came across some words that have different spellings, different pronunciations or different expressions, which can be represented by following contrasted words: spellings in "color" vs. "colour"; pronunciations in "sec-re-ta-ry" vs. "sec-re-try";
关于毕业设计说明书（论文）英文文献及中文翻译撰写格式 为提高我校毕业生毕业设计说明书（毕业论文）的撰写质量，做到毕业设计说明书（毕业论文）在内容和格式上的统一和规范，特规定如下: 一、装订顺序 论文（设计说明书）英文文献及中文翻译内容一般应由3个部分组成，严格按以下顺序装订。 1、封面 2、中文翻译 3、英文文献（原文） 二、书写格式要求 1、毕业设计（论文）英文文献及中文翻译分毕业设计说明书英文文献及中文翻译和毕业论文英文文献及中文翻译两种，所有出现相关字样之处请根据具体情况选择“毕业设计说明书” 或“毕业论文”字样。 2、毕业设计说明书（毕业论文）英文文献及中文翻译中的中文翻译用Word 软件编辑，英文文献用原文，一律打印在A4幅面白纸上，单面打印。 3、毕业设计说明书（毕业论文）英文文献及中文翻译的上边距:30mm；下边距:25mm；左边距:3Omm；右边距:2Omm；行间距1.5倍行距。 4、中文翻译页眉的文字为“中北大学2019届毕业设计说明书” 或“中北大学××××届毕业论文”，用小四号黑体字，页眉线的上边距为25mm；页脚的下边距为18mm。 5、中文翻译正文用小四号宋体，每章的大标题用小三号黑体，加粗，留出上下间距为：段前0.5行，段后0.5行；二级标题用小四号黑体，加粗；其余小标题用小四号黑体，不加粗。 6、文中的图、表、附注、公式一律采用阿拉伯数字分章编号。如图1.2，表2.3，附注3.2或式4.3。 7、图表应认真设计和绘制,不得徒手勾画。表格与插图中的文字一律用5号宋体。
每一插图和表格应有明确简短的图表名，图名置于图之下，表名置于表之上，图表号与图表名之间空一格。插图和表格应安排在正文中第一次提及该图表的文字的下方。当插图或表格不能安排在该页时，应安排在该页的下一页。 图表居中放置，表尽量采用三线表。每个表应尽量放在一页内，如有困难，要加“续表X.X”字样，并有标题栏。 图、表中若有附注时，附注各项的序号一律用阿拉伯数字加圆括号顺序排，如:注①。附注写在图、表的下方。 文中公式的编号用圆括号括起写在右边行末顶格，其间不加虚线。 8、文中所用的物理量和单位及符号一律采用国家标准，可参见国家标准《量和单位》(GB3100~3102-93)。 9、文中章节编号可参照《中华人民共和国国家标准文献著录总则》。
MCS-51系列单片机 中英文资料对照外文翻译文献综述 Structure and function of the MCS-51 series Structure and function of the MCS-51 series one-chip computer MCS-51 is a name of a piece of one-chip computer series which Intel Company produces. This company introduced 8 top-grade one-chip computers of MCS-51 series in 1980 after introducing 8 one-chip computers of MCS-48 series in 1976. It belong to a lot of kinds this line of one-chip computer the chips have, such as 8051, 8031, 8751, 80C51BH, 80C31BH,etc., their basic composition, basic performance and instruction system are all the same.8051 daily representatives-51 serial one-chip computers. A one-chip computer system is made up of several following parts: (1) One microprocessor of 8 (CPU). ( 2) At slice data memory RAM (128B/256B),it use not depositing not can reading /data that write, such as result not middle of operation, final result and data wanted to show, etc. (3) Procedure memory ROM/EPROM (4KB/8K B ), is used to preserve the
2604130359 CNC Cutting Technology Review Numerical control high speed cutting technology (High Speed Machining, HSM, or High Speed Cutting, HSC), is one of the advanced manufacturing technology to improve the machining efficiency and quality, the study of related technology has become an important research direction of advanced manufacturing technology at home and abroad. China is a big manufacturing country, in the world of industry transfer to accept the front instead of back-end of the transfer, to master the core technology of advanced manufacturing, or in a new round of international industrial structure adjustment, our country manufacturing industry will further behind. Imminent research on the theory and application of advanced technology. 1, high-speed CNC machining meaning High speed cutting theory put forward by the German physicist Carl.J.Salomon in the last century and early thirty's. He concluded by a lot of experiments: in the normal range of cutting speed, cutting speed if the increase, will cause the cutting temperature rise, exacerbating the wear of cutting tool; however, when the cutting speed is increased to a certain value, as long as more than the inflection point, with the increase of the cutting speed, cutting temperature can not rise, but will decline, so as long as the cutting speed is high enough, it can be solved very well in high cutting temperature caused by tool wear is not conducive to the cutting problem, obtained good processing efficiency. With the development of manufacturing industry, this theory is gradually paid more attention to, and attracted a lot of attention, on the basis of this theory has gradually formed the field of high-speed cutting technology of NC, relatively early research on NC High-speed Machining Technology in developed countries, through the theoretical basis of the research, basic research and applied research and development application, at present applications have entered the substantive stage in some areas. The high-speed cutting processing category, generally have the following several kinds of classification methods, one is to see that cutting speed, cutting speed over conventional cutting speed is 5-10 times of high speed cutting. Also has the scholar to spindle speed as the definition of high-speed processing standards, that the spindle speed is higher than that of 8000r\/min for high speed machining. And from the machine tool spindle design point of view, with the product of DN diameter of spindle and spindle speed, if the value of DN to (5~2000) * 105mm.r\/min, is considered to be of high speed machining. In practice, different processing methods, different materials, high speed cutting speed corresponding to different. Is generally believed that the turning speed of (700~7000) m\/min, milling speed reaches m\/min (300~6000), that is in the high-speed cutting. In addition, from the practical considerations, high-speed machining concept not only contains the high speed cutting process, integration and optimization also contains the process of cutting, is a
英语专业文献翻译 题目: 基于交通服务感知质量的效用评价方法姓名: 丁贞钰 学院: 工学院 专业: 交通运输 班级: 101班 学号: 30210101 指导教师: 陈青春职称: 副教授 2013年11月25日 南京农业大学教务处制
基于交通服务感知质量的效用评价方法 Hideyuki Kita a Akira Kouchi b a Department of Civil Engineering, Graduate School of Engineering, University of Kobe, 1-1, Rokkodai-cho, Nada-ku, Kobe, 658-8501, Japan b Infrastructural Planning Department, Chodai Co. Ltd., 2-20-6, Shin-machi, Nishi-ku, Osaka, 550-0013, Japan 摘要：本研究旨在开发一个通过宏观交通状态数据评价微观驾驶环境的模型，并且展示一系列基于驾驶员视觉的交通服务质量估算方法的模型。该方法由三部分组成，第一部分通过宏观数据评价行驶速度和时间间隔分配，第二部分评价作为行驶速度和时间间隔联合概率的基点效用。第三部分通过利用经验公式的基点概率分布估计基段效用。通过一个研究案列论证所提出的方法。 关键词：驾驶员感知；交通服务质量；基础效用评价；估计方法；交通调查数据；相关函数 1 引言 交通服务质量直接关系到驾驶员的利益。为了提高交通服务质量，应采取必要措施提高驾驶员对道路规划和交通管理的满意度。采取适当的基于驾驶员感知的方法来评价路用性能是必要的。弄清驾驶员服务质量感知结构对区分驾驶员感知服务质量也是必要的。 从驾驶员感知的角度对服务质量的评价已经有了很大成就,研究人员对评价驾驶员感知结构的感知服务质量做了比以前更多的尝试，但是感知服务质量的层次结构依旧很少被人认识。基于驾驶员的感知结构的层次结构，包括基点服务质量、基段服务质量和基面服务质量。通过参考感知结构的服务质量，Kita(2000)提出了测量服务质量的方法的基本框架。这个框架的基本思想是服务质量的最小单位是微观驾驶环境，比如在每个路段驾驶员的视野范围内相对速度和空间时间间隔。驾驶员对于特定路段的服务质量感知是这些基点服务质量的集合。然而关于感知服务质量的重要因素—微观驾驶环境的数据却很难获得。另一方面，宏观交通状态变量，比如由微观交通状况变量集合的数据—速率，可以很容易的通过车辆检测器。在给定宏观交通状况下，捕捉发生在什么样的微观环境和到什么程度是必要的。但是，没有研究与以上观点相关，直到本文作者对他的认识。 本研究的目的是开发一个通过宏观交通状况变量评价微观驾驶环境的方法，并提出一系列对宏观交通状态变量的基点服务质量的测量和对根据驾驶感知结构和服务质量层次结构基点服务质量的基段服务质量的测量方法。通过使用上面的方法，获得有关驾驶员感知结构的宏观交通状况数据，评价基于驾驶员感知的基段服务质量。 本文组织如下。第2部分，概括评价服务质量领域的相关文献。第3部分，表述包括提出的方法论的一系列方法的概要和基本思想。第4部分，概述运用宏观交通状态变量估计微观驾驶环境的方法。第5部分，开发了一种联系基点感知服务质量和考虑认知倾向的基段感知服务质量的模型，并对概率分布之间的关系效用进行微观分析。第6部分，通过运用从车辆检测器上获得的实际交通状况数据检测本文所表述的理论模型的有效性。第7部分，结论。 2 文献综述 已经做过很多关于驾驶员感知的服务质量评价工作。但由于篇幅有限，只把文献大纲列出如下。更多信息可以从Kita and Kouchi(2010)中获得。有一些研究阐述了交通服务质量应该基于驾驶员的微观驾驶环境的感知评价交通服务质量(Morrall and Werner (1990), Ishibashi et al. (2006))。有一些研究试图找到一个可以展现与感知交通服务质
Advantages of Managed Code Microsoft intermediate language shares with Java byte code the idea that it is a low-level language witha simple syntax , which can be very quickly translated intonative machine code. Having this well-defined universal syntax for code has significant advantages. Platform independence First, it means that the same file containing byte code instructions can be placed on any platform; atruntime the final stage of compilation can then be easily accomplished so that the code will run on thatparticular platform. In other words, by compiling to IL we obtain platform independence for .NET, inmuch the same way as compiling to Java byte code gives Java platform independence. Performance improvement IL is actually a bit more ambitious than Java bytecode. IL is always Just-In-Time compiled (known as JIT), whereas Java byte code was ofteninterpreted. One of the disadvantages of Java was that, on execution, the process of translating from Javabyte code to native executable resulted in a loss of performance. Instead of compiling the entire application in one go (which could lead to a slow start-up time), the JITcompiler simply compiles each portion of code as it is called (just-in-time). When code has been compiled.once, the resultant native executable is stored until the application exits, so that it does not need to berecompiled the next time that portion of code is run. Microsoft argues that this process is more efficientthan compiling the entire application code at the start, because of the likelihood that large portions of anyapplication code will not actually be executed in any given run. Using the JIT compiler, such code willnever be compiled.
中文资料原文 单片机 单片机也被称为微控制器（Microcontroller Unit），常用英文字母的缩写MCU表示单片机，它最早是被用在工业控制领域。单片机由芯片内仅有CPU的专用处理器发展而来。最早的设计理念是通过将大量外围设备和CPU集成在一个芯片中，使计算机系统更小，更容易集成进复杂的而对体积要求严格的控制设备当中。INTEL的Z80是最早按照这种思想设计出的处理器，从此以后，单片机和专用处理器的发展便分道扬镳。 早期的单片机都是8位或4位的。其中最成功的是INTEL的8031，因为简单可靠而性能不错获得了很大的好评。此后在8031上发展出了MCS51系列单片机系统。基于这一系统的单片机系统直到现在还在广泛使用。随着工业控制领域要求的提高，开始出现了16位单片机，但因为性价比不理想并未得到很广泛的应用。90年代后随着消费电子产品大发展，单片机技术得到了巨大提高。随着INTEL i960系列特别是后来的ARM系列的广泛应用，32位单片机迅速取代16位单片机的高端地位，并且进入主流市场。而传统的8位单片机的性能也得到了飞速提高，处理能力比起80年代提高了数百倍。目前，高端的32位单片机主频已经超过300MHz，性能直追90年代中期的专用处理器，而普通的型号出厂价格跌落至1美元，最高端[1]的型号也只有10美元。当代单片机系统已经不再只在裸机环境下开发和使用，大量专用的嵌入式操作系统被广泛应用在全系列的单片机上。而在作为掌上电脑和手机核心处理的高端单片机甚至可以直接使用专用的Windows和Linux操作系统。 单片机比专用处理器更适合应用于嵌入式系统，因此它得到了最多的应用。事实上单片机是世界上数量最多的计算机。现代人类生活中所用的几乎每件电子和机械产品中都会集成有单片机。手机、电话、计算器、家用电器、电子玩具、掌上电脑以及鼠标等电脑配件中都配有1-2部单片机。而个人电脑中也会有为数不少的单片机在工作。汽车上一般配备40多部单片机，复杂的工业控制系统上甚至可能有数百台单片机在同时工作！单片机的数量不仅远超过PC机和其他计算的总和，甚至比人类的数量还要多。 单片机又称单片微控制器,它不是完成某一个逻辑功能的芯片,而是把一个计算机系统集成到一个芯片上。相当于一个微型的计算机，和计算机相比，单片机只缺少了I/O设备。概括的讲：一块芯片就成了一台计算机。它的体积小、质量轻、价格便宜、为学习、应用和开发提供了便利条件。同时，学习使用单片机是了解计算机原理与结构的最佳选择。
A review and analysis of current computer-aided fixture design approaches Iain Boyle, Yiming Rong, David C. Brown Keywords: Computer-aided fixture design Fixture design Fixture planning Fixture verification Setup planning Unit design ABSTRACT A key characteristic of the modern market place is the consumer demand for variety. To respond effectively to this demand, manufacturers need to ensure that their manufacturing practices are sufficiently flexible to allow them to achieve rapid product development. Fixturing, which involves using fixtures to secure work pieces during machining so that they can be transformed into parts that meet required design specifications, is a significant contributing factor towards achieving manufacturing flexibility. To enable flexible fixturing, considerable levels of research effort have been devoted to supporting the process of fixture design through the development of computer-aided fixture design (CAFD) tools and approaches. This paper contains a review of these research efforts. Over seventy-five CAFD tools and approaches are reviewed in terms of the fixture design phases they support and the underlying technology upon which they are based. The primary conclusion of the review is that while significant advances have been made in supporting fixture design, there are primarily two research issues that require further effort. The first of these is that current CAFD research is segmented in nature and there remains a need to provide more cohesive fixture design support. Secondly, a greater focus is required on supporting the detailed design of a fixture’s physical structure. 2010 Elsevier Ltd. All rights reserved. Contents 1. Introduction (2) 2. Fixture design (2) 3. Current CAFD approaches (4) 3.1 Setup planning (4) 3.1.1 Approaches to setup planning (4) 3.2 Fixture planning (4) 3.2.1 Approaches to defining the fixturing requirement (6) 3.2.2 Approaches to non-optimized layout planning (6) 3.2.3 Approaches to layout planning optimization (6) 3.3 Unit design (7) 3.3.1 Approaches to conceptual unit design (7)