科技文献中英文对照翻译
科技文献中英文摘要范文
科技文献中英文摘要范文English:Nowadays, with the rapid advancement of technology, there has been increasing interest in applying artificial intelligence (AI) to various fields such as healthcare, finance, transportation, and more. AI has the potential to revolutionize these industries by improving efficiency, accuracy, and decision-making processes. In healthcare, AI tools can assist doctors in diagnosing diseases, predicting patient outcomes, and even personalizing treatment plans. In finance, AI algorithms can analyze market trends, predict stock prices, and detect fraudulent activities. In transportation, AI can optimize routes, reduce traffic congestion, and improve safety measures. Despite the great benefits AI can bring, there are also ethical and privacy concerns that need to be addressed. It is essential for policymakers, researchers, and industry professionals to work together to ensure responsible and ethical AI development.中文翻译:如今，随着科技的快速发展，人们越来越热衷于将人工智能（AI）应用于医疗保健、金融、交通等各个领域。
经典翻译范文之科技篇中英文对照
中国热门科技词汇科学发展观concept of scientific development全民科学文化素质scientific and cultural qualities of the entire people 发展科技scientific and technological advancement科教兴国revitalize China through science and education 农业技术agricultural technology[扩展]白色农业 white agriculture （microbiological agriculture and biological cell agriculture）超级杂交水稻super-hybrid rice技术下乡spreading the application of science and technology in rural areas节水农业water-saving agriculture立体农业3-D agriculture农产品加工及转化the processing and commercialization of agro-products 农业科技agro-science农作物良种seeds of high-quality crop农作物新品种选育the selection and breeding of new crops 生态农业environmental-friendly agriculture无土栽培soil -less cultivationBP机，传呼beeper, pager背投屏幕rear projection screen不明飞行物unidentified flying object （UFO）操作系统operating system产品科技含量technological element of a product创新innovation电话会议teleconference电话留言机answering machine对讲机talkie and walkie多媒体multimedia二期the second phase防抱死系统ABS （anti-lock braking system）孵化器incubator高产优质high yield and high quality高技术产业化apply high technology to production高科技板块high-tech sector高科技园high-tech park个人数字助理PDA （personal digital assistant）工业园区industrial park国家质量技术监督局the State Bureau of Quality and Technical Supervision 国家重点实验室national key laboratories火炬计划Torch Program （a plan to develop new and high technology）计算机中央处理器central processing unit（CPU）技术产权technology property right技术交底confide a technological secret to someone.技术密集产品technology-intensive product交叉学科interdisciplinary branch of science科技成果转化为生产力 transfer of scientific and technological achievements into productive forces科技含量technology content科技基础设施science and technology infrastructure科技是第一生产力Science and technology constitute a primary productive for ce科技体制改革reform of the science and technology management system科技与经济脱节science and technology are out of line from the economy科教兴国rejuvenate the country through science and education可持续发展战略strategy of sustainable development纳米nanometer三峡水利枢纽工程the key water control project at the Three Gorges on the Yangtze River物种起源origin of species新兴学科new branch of science研究成果research results在孵企业incubated enterprises自动取款机automatic teller machine （ATM）自然科学与社会科学的交叉融合integration of natural and social sciencesIT 信息技术[扩展]信息港info port信息高地information highland信息高速公路information superhighway信息革命information revolution信息含量information content信息化informationization信息技术处理ITA - Information Technology Agreement 信息检索information retri办公自动化OA （Office Automation）笔记本电脑laptop / notebook / portable computer 电脑病毒computer virus电脑犯罪computer crime电子管理e-management电子货币e-currency电子商务e-business; e-commerce电子商务认证e-business certification电子邮件E-mail非对称数字用户环路ADSL （Asymmetrical Digital Subscriber Loop）高速宽带互联网high-speed broadband networks公告板BBS （bulletin board system）光盘杂志CD-ROM magazine广域网WAN （wide area net word）汉字处理软件Chinese character processing software黑客hacker计算机2000年问题Y2K problem计算机辅助教育CAI -computer assisted instruction计算机辅助设计CAD-computer assisted design计算机合成制造CAM-computer assisted manufacturing计算机中央处理器CPU - central processing unit超文本传送协议hypertext transfer protocol （HTTP）界面interface金融电子化computerized financial services局域网LAN - local area network互联网服务提供商ISP （Internet Service Provider）全球移动通信系统（全球通）global system for mobile communications （GSM）刻录机CD burner宽带接入broadband access宽带网broadband networks内联网、局域网（计算机）Intranet垃圾邮件junk mail千年问题、千年虫millennium bug; Y2K bug 人工智能AI - artificial intelligence人机交互human - computer interaction人机交互human-computer interaction虚拟人visual human虚拟网virtual net虚拟网virtual net虚拟现实virtual reality虚拟银行virtual bank因特网服务提供商ISP- internet service provider万维网World Wide Web（WWW）应用软件internet applications域名domain在线on line掌上电脑palm computer政府上网工程Government Online Project只读存储器read-only-memory （ROM）智能感知技术perceptive technology智能终端intelligent terminal中文信息处理系统Chinese information processing system数码科技digital technology高保真Hi-Fi （High Fidelity）高清晰度电视high definition TV （HDTV）光谷optical valley光通讯optical communication蓝光光盘Blue -ray Disc数码港cyber port数字地球digital globe数字蜂窝移动通信digital cellular mobile telecommunications三维电影three-dimensional movie三维动画three-dimensional animation[详析] “蓝光光盘”利用蓝色的激光束来刻录数据。
英文文献 科技类 原文及翻译 64
13.3.3 C类放大器在C类功率放大器中，栅的偏压设成使晶体管在小于一半的时间内导通。
因此，漏极电流是由周期性的一串脉冲构成的。
传统上用正弦的上面部分来近似这些脉冲以便于进行直接分析②。
特别是我们假设漏极电流具有如下的形式：式中，偏置值I DC类似于线性放大器中的偏置电流，它对于C类放大器实际上是负值。
自然，整个漏极电流i D心总是为正或为零。
也就是说，漏极电流在晶体管导通时是一段正弦波，而在晶体管截止时为零。
我们继续假设晶体管在任何时候的工作情况都像是一个电流源(高输出阻抗)③。
由于我们仍然有一个高Q值的输出振荡回路，所以在负载两端的电压基本上保持为正弦，因此漏极电压和漏极电流如图13.4所示。
在以下的推导中，不必担心能否重复所有的这些细节。
正如我们将要看到的，我们如何设计这样的放大器与这些公式本身的含义有显著的不同，所以重点要放在所得到的一般结论而不是一些具体细节上。
我们从求解漏极电流不为零时总的导通角开始。
为了简化得到这一答案所需要的步骤，我们首先用余弦而不是正弦来重新写出漏极电流的表达式：显然，这样做没有任何改变，因为时间原点总是任选的。
在经过这样的修改之后，电流脉冲就如图13．5所示。
使电流等于零并求出总的导通角2中得到：我们现在可以计算平均漏极电流为:在用I DC的表达式替换后得到:我们将很快用这个表达式来推导效率作为导通角函数的公式。
我们需要的另一个量是传送到负载的功率的一般表达式。
正如与B类放大器一样由于高Q值的振荡回路而被简化，所以我们只需要计算傅里叶级数中的基波项：利用我们通过负载的基波电流的表达式，我们可以很容易地推导出最大输出电压摆幅的公式：上式允许我们求解用V DD表示的电流irf:峰值漏极电流为irf与偏置项的和为：上式可简化为:对于固定的输出电压，当脉冲宽度减小至零时，峰值漏极电流接近无穷大。
利用我们刚刚推导的公式可以很容易地计算出漏极效率为：当导通角缩小至零时，效率接近100％。
科技文献翻译
科技文献翻译Technology has transformed every aspect of our lives, from the way we communicate and work to how we shop and entertain ourselves. With the rapid advancement of technology, there is a growing demand for accurate translations of technology-related literature. This article aims to provide a translation of a technology paper consisting of 700 words.The paper titled "The Role of Artificial Intelligence in Autonomous Vehicles" explores the impact of AI in self-driving cars. Autonomous vehicles have gained significant attention in recent years due to their potential to revolutionize transportation. This paper discusses how AI technologies, such as deep learning and machine vision, have contributed to the development of autonomous vehicles.一项名为“人工智能在自动驾驶汽车中的角色”的研究探讨了AI在无人驾驶汽车中的影响。
在过去几年中，由于其改变出行方式的潜力，自动驾驶汽车引起了广泛关注。
科技文献中英文翻译
Intelligent Power Supply英文With the rapid development of electronic technology, application field of electronic system is more and more extensive, electronic equipment, there are more and more people work with electronic equipment, life is increasingly close relationship. Any electronic equipment are inseparable from reliable power supply for power requirements, they more and more is also high. Electronic equipment miniaturized and low cost in the power of light and thin,small and efficient for development direction. The traditional transistors series adjustment manostat is continuous control linear manostat. This traditional manostat technology more mature, and there has been a large number of integrated linear manostat module, has the stable performance is good, output ripple voltage small, reliable operation, etc. But usually need are bulky and heavy industrial frequency transformer and bulk and weight are big filter.In the 1950s, NASA to miniaturization, light weight as the goal, for a rocket carrying the switch power development. In almost half a century of development process, switch power because of is small volume, light weight, high efficiency, wide range, voltage advantages in electric, control, computer, and many other areas of electronic equipment has been widely used. In the 1980s, a computer is made up of all of switch power supply, the first complete computer power generation. Throughout the 1990s, switching power supply in electronics,electrical equipment, into the rapid development. In addition, large scale integrated circuit technology, and the rapid development of switch power supply with a qualitative leap, raised high frequency power products of, miniaturization, modular tide.Power switch tube, PWM controller and high-frequency transformer is an indispensable part of the switch power supply. The traditional switch power supply is normally made by using high frequency power switch tube division and the pins, such as using PWM integrated controller UC3842 + MOSFET is domestic small power switch power supply, the design method of a more popularity.Since the 1970s, emerged in many function complete integrated control circuit, switch power supply circuit increasingly simplified, working frequency enhancesunceasingly, improving efficiency, and for power miniaturization provides the broad prospect. Three end off-line pulse width modulation monolithic integrated circuit TOP (Three switch Line) will Terminal Off with power switch MOSFET PWM controller one package together, has become the mainstream of switch power lC development. Adopt TOP switch lC design switch power, can make the circuitsimplified,volume further narrowing, cost also is decreased obviousiy.Monolithic switching power supply has the monolithic integrated, the minimalist peripheral circuit, best performance index, no work frequency transformer can constitute a significant advantage switching power supply, etc. American Pl (with) company in Power in the mid 1990s first launched the new high frequency switching Power supply chip, known as the "top switch Power", with low cost, simple circuit, higher efficiency. The first generation of products launched in 1994 represented TOP100/200 series, the second generation product is the TOPSwitch - debuted in 1997 П .The above products once appeared showed strong vitality and he greatly simplifies the design of 150W following switching power supply and the development of new products for the new job, also, high efficiency and low cost switch power supply promotion and popularization created good condition, which can be widely used in instrumentation, notebook computers, mobile phones, TV, VCD and DVD, perturbation VCR, mobile phone battery chargers, power amplifier and other fields, and form various miniaturization, density, on price can compete with the linear manostat AC/DC power transformation module.Switching power supply to integrated direction of future development will be the main trend, power density will more and more big, to process requirements will increasingly high. In semiconductor devices and magnetic materials, no new breakthrough technology progress before major might find it hard to achieve, technology innovation will focus on how to improve the efficiency and focus on reducing weight. Therefore, craft level will be in the position of power supply manufacturing higher in. In addition, the application of digital control IC is the future direction of the development of a switch power. This trust in DSP for speed and anti-interference technology unceasing enhancement. As for advanced control method, now the individual feels haven't seen practicability of the method appears particularly strong, perhaps with the popularity of digital control, and there are some new control theory into switching power supply.(1) The technology: with high frequency switching frequencies increase, switchconverter volume also decrease,power density has also been boosted, dynamic response improved. Small power DC - DC converter switch frequency will rise to MHz. But as the switch frequency unceasing enhancement, switch components and passive components loss increases, high-frequency parasitic parameters and high-frequency EMI and so on the new issues will also be caused．(2) Soft switching technologies: in order to improve the efficiency of non-linearity of various soft switch, commutation technical application and hygiene, representative of soft switch technology is passive and active soft switch technology, mainly including zero voltage switch/zero current switch (ZVS/ZCS) resonance, quasi resonant, zero voltage/zero current pulse width modulation technology (ZVS/ZCS - PWM) and zero voltage transition/zero current transition pulse width modulation (PWM) ZVT/ZCT - technical, etc. By means of soft switch technology can effectively reduce switch loss and switch stress, help converter transformation efficiency.(3) Power factor correction technology (IC simplifies PFC). At present mainly divided into IC simplifies PFC technology passive and active IC simplifies PFC technology using IC simplifies PFC technology two kinds big, IG simplifies PFC technology can improve AC - DC change device input power factor, reduce the harmonic pollution of power grid.(4) Modular technology. Modular technology can meet the needs of the distributed power system, enhance the system reliability.(5) Low output voltage technology. With the continuous development of semiconductor manufacturing technology, microprocessor and portable electronic devices work more and more low, this requires future DC - DG converter can provide low output voltage to adapt microprocessor and power supply requirement of portable electronic devicesPeople in switching power supply technical fields are edge developing related power electronics device, the side of frequency conversion technology, development of switch between mutual promotion push switch power supply with more than two year growth toward light, digital small, thin, low noise and high reliability, anti-interference direction. Switching power supply can be divided into the AC/DC and DC/DC two kinds big, also have AC/AC DC/AC as inverter DC/DC converter is now realize modular, and design technology and production process at home and abroad, are mature and standardization, and has approved by users, but the AC/DC modular, because of its own characteristics in the process of making modular, meetmore complex technology and craft manufacture problems. The following two types of switch power supply respectively on the structure and properties of this.Switching power supply is the development direction of high frequency, high reliability, low consumption, low noise, anti-jamming and modular. Because light switch power, small, thin key techniques are changed, so high overseas each big switch power supply manufacturer are devoted to the development of new high intelligent synchronous rectifier, especially the improvement of secondary devices of the device, and power loss of Zn ferrite (Mn) material? By increasing scientific and technological innovation, to enhance in high frequency and larger magnetic flux density (Bs) can get high magnetic under the miniaturization of, and capacitor is a key technology. SMT technology application makes switching power supply has made considerable progress, both sides in the circuit board to ensure that decorate components of switch power supply light, small, thin. The high frequency switching power supply of the traditional PWM must innovate switch technology, to realize the ZCS ZVS, soft switch technology has become the mainstream of switch power supply technical, and greatly improve the efficiency of switch power. For high reliability index, America's switch power producers, reduce by lowering operating current measures such as junction temperature of the device, in order to reduce stress the reliability of products made greatly increased．Modularity is of the general development of switch power supply trend can be modular power component distributed power system, can be designed to N + 1 redundant system, and realize the capacity expansion parallel. According to switch power running large noise this one defect, if separate the pursuit of high frequency noise will increase its with the partial resonance, and transform circuit technology, high frequency can be realized in theory and can reduce the noise, but part of the practical application of resonant conversion technology still have a technical problem, so in this area still need to carry out a lot of work, in order to make the technology to practional utilization.Power electronic technology unceasing innovation, switch power supply industry has broad prospects for development. To speed up the development of switch power industry in China, we must walk speed of technological innovation road, combination with Chinese characteristics in the joint development path, for the high-speed development of national economy to make the contribution.中文智能开关电源随着电子技术的高速发展，电子系统的应用领域越来越广泛，电子设备的种类也越来越多，电子设备与人们的工作、生活的关系口益密切。
英文文献 科技类 原文及译文33
Multi-texture-model for Water Extraction Based on Remote Sensing ImageHua WANG, Li PAN, Hong ZHENGSchool of Remote Sensing and Information & Engineering, Wuhan University 129 Luoyu Road,Wuhan 430079,P.R.ChinaSchool of Electronic Information, Wuhan University 129 Luoyu Road, Wuhan 430079,P.R.ChinaAbstract:In this paper, a multi-texture-model for water extraction based on remote sensing imagery is proposed. The model is applied to extract inland water (including wide river, lake and reservoir)from high-resolution panchromatic images. Firstly directional variance is used to find river regions, and then grain table is adopted to avoid noise including objects that have similar directional variance characteristic as water surfaces. The experiment result shows that the proposed method provides an effective way for water extraction.1. IntroductionThe recognition of water from remote sensing image has drawn considerable attention in recent yeas. A large number of publications about water extraction appeared and various approaches for water extraction have been proposed. Zhou developed a descriptive model for automatic extraction of water based on spectral characteristics[1]. Barton applied channel 4 for NOAA/AVHRR to extract water[2]. Du proposed a approach for water extraction from SPOT-5 based on decision tree algorithm[3]. Li recognized and monitored clear water from MODIS[4]. Wu extracted water from Quick Bird image and used active contour model to obtain accurate position of river bank[5]; In order to extract water from high-spatial remote sensing images, He used wavelet technique to expend the information and cleaned main noise of the images, and then presented multi-window linearity reserve technique to conserve linear water[6].Recently, most research work on water extraction was forced on automatic recognition of water from remote sensing images based on spectral characteristics. However, there are some disadvantages of these methods: (1) The resolution of image used for water extraction is low. The minimum size of recognizable object is depended on the spatial resolution of sensor. Therefore it is difficult to obtain accurate position of water boundary. (2) Due to the characteristic of water itself and the sensor applied, in certain channels the spectral features of different objects are equilibrated. The equilibration leads to the phenomena of “different objects same image” or“different images same object”, which results in noise objects included in extraction result.In this paper, a multi-texture-model for water extraction based on remote sensing is proposed. The model is applied to extract inland water (including wide river, lake and reservoir) fromhigh-resolution panchromatic image. Firstly directional variance is applied to find river regions, and then grain table is adopted to avoid noise including objects that have similar directional variance characteristic as water surfaces. The experiment result shows that the proposed method provides an effective way for water extraction.This paper is organized as follows. In Section 2, the directional variance model adopted is introduced. Then, fusion of proposed grain table model with directional variance model is discussed in Section 3.The experimental results of the proposed multi-texture-model and comparative studies with single models are given in Section 4. We conclude this paper in Section 5.2. Directional Variance ModelThe aim of our research is to extract water larger than 100m2from panchromatic images. As shown in Figure 2(a), the research objects can be divided into three classes: wide river, lake and reservoir, which all represent as region in high-resolution imageries. The objects of background can be divided into two classes: building and cropland, which also represent as region.In panchromatic imagery, wide river has a similar gray level to building and cropland, though the mean grayof lake and reservoir is much lower than the background objects. Conventional methods for water extraction based on spectral characteristics are not effective in the situation. In the meantime, water body defines homogeneous areas whereas building and cropland correspond to heterogeneous regions. Therefore, we take into account the homogeneity of the image to separate wide river, lake and reservoir from background instead. To characterize the difference of homogeneity between water body and the other types of areas, we use a textual operator: the directional variance.2.1. The Directional Variance OperatorThe operator is derived from those defined by Guerin & Maitre and Airault & Jamet[10]. As shown in Figure1, the directional variance consists in computing, for each pixel M of the image, the variance of the gray levels of the image on several direction of a circle whose center is M and radius is R. Then, the direction with the highest variance value is kept. Its direction defines the direction for which image is the most heterogeneous, locally. Its variance value is the directional variance value of the pixel M.2.2. Extraction of water based on directional varianceAccording to the definition of the operator, the minimum acreage of recognizable water body is depended on the length of radius R. We have chosen a length of 10 pixels for 1m resolution. The directional variances of the five typical training samples (wide river, lake, reservoir, building and cropland) have been computed and the statistical comparison is summarized in Table1. The overall average of water directional variance is lower than the objects of background.Nevertheless, the directional variance of cropland is similar to wide river with overlapping potion over 90%.Inhigh-resolution panchromatic imagery, details inside wide river, such as boat, wave, etc, are represented clearly which result in the heterogeneous of water. In the meantime, the textures of parts of building (for example, roof ) and cropland are rather fine. In a small window, these potions define homogeneous areas with similar directional variance as wide river. The result is improved if we chosen a length of 100 pixels. The statistical comparison is shown in Table2. If the length of radius is large enough, directional variance of building is higher than other objects obviously with no overlapping portion; the difference between cropland and wide river is increased while the overlapping potion is decreased. However, increasing the radius leads to two problems which are outlined as follow:1) The size of recognizable water body increases;therefore water which has small acreage (for example narrow river) can not be detected.2) The position of water bank is not accurate although the spatial resolution of imagery is rather high.Hence, in this paper, a multi-texture-model is presented and two texture models are fused to extract water from panchromatic images. Firstly, we chose a radius of 10 pixels to extract water based on directional variance; and then, grain table is adopted to avoid noise including parts of building and cropland that have similar directional variance characteristic as water surface.3. Multi-texture-modelIn high-resolution imagery, cropland and building represents structural characteristic. According to this characteristic, grain analysis is adopted for further research on the original extraction based on directional variance. The grain table histogram is able to represent structural characteristic of the research object, which can be applied to recognize many kinds of different objects [12].3.1. Extraction of water fused by grain tableThe grain table histograms of the five typical training samples (wide river, lake, reservoir, building and cropland) are computed and correlation coefficients between them are summarized in Table3. Correlation coefficients between water classes are over 85%, however, correlation coefficients between water classes and background classes are lower than 65%.Hence, we compare the correlation coefficients of regions in extraction image base on directional variance with three water samples and two background samples respectively. If the region has a higher correlation coefficient with background classes, it will be marked background and wiped off[13].4.Experimental ResultsWe run the algorithm on several high-resolution panchromatic images. In Figure2.(a), we have been considering an aerial photograph(6126×4800) of a region in Wuhan, China, the resolution of which is 1m,including building, cropland, wide river( Changjiang river), lake, reservoir and cropland. The results of extraction based on directional variance with radius of 10 pixels is displayed in Figure2.(b), and clearly, water has been detected completely, whereas parts of building and cropland are included as noise objects in the result. Water extraction using directional variance with radius of 100 pixels is displayed in Figure2.(c)with correctness over 95%, however, small lakes are missed and the position of bank is not as accurate as Figure2.(b). Finally, in Figure2.(d), the result of Figure2.(b) is fused by grain table analysis, so that the correctness and completeness of extraction are both over 90%.5. ConclusionsBased on textural analysis of water in high-resolution panchromatic imagery, a multi-texture-model is presented for water extraction.The experimental results proved that the approach is efficient for inland water (including wide river, lake and reservoir) extraction. As the complexity and diversity of water, the rate of recognition of our algorithm fluctuates. Furthermore, the method is supervised which needs a lot of human interference to obtain training samples. Therefore, there are problems to be solved in future:1) Our further work should be extensible to multispectral remote sensing images.2) To decrease human interference, old vector will be applied to obtain training samples instead. 6. AcknowledgmentsThe work was supported by the National Key Technology R&D Program of China under grant No.2006BAB10B01.根据遥感图象的多纹理模型相关的水抽取Hua WANG, Li PAN, Hong ZHENGSchool of Remote Sensing and Information & Engineering, Wuhan University 129 Luoyu Road,Wuhan 430079,P.R.ChinaSchool of Electronic Information, Wuhan University 129 Luoyu Road, Wuhan 430079,P.R.China文摘：在本文中，提议了一个多纹理模型为根据遥感成像的水提取。
英文文献科技类原文及翻译
本科毕业设计(论文)外文翻译姓名: 王文超学号： 200715010220专业: 电气工程及其自动化班级: 电气071502指导教师: 智泽英职称：副教授日期: 2011年6月12日电子信息工程学院The basics of Computer Numerical ControlWhile the specific intention and application for CNC machines vary from machine type toanother, all forms of CNC have common benefits. Though the thrust of this presentation is to teach you CNC usage, it helps to understand why these sophisticated machines have become so popular. Here are but a few of the more important benefits offered by CNC equipment.The first benefit offered by all forms of CNC machine tools is improved automation. The operator intervention related to producing workpieces can be reduced or eliminated. Many CNC machines can run unattended during their entire machining cycle, freeing the operator to do other tasks. This gives the CNC user several side benefits including reduced operator fatigue, fewer mistakes caused by human error, and consistent and predictable machining time for each workpiece. Since the machine will be running under program control, the skill level required of the a CNC operator (related to basic machining practice) is also reduced as compared to a machinist producing workpieces with conventional machine tools.The second major benefit of CNC technology is consistent and accurate workpieces. Today’s CNC machines boast almost unbelievable accuracy and repeatability specifications. This means that once a program is verified, two, ten, or one thousand identical workpieces can be easily produced with precision and consistency.A third benefit offered by most forms of CNC machine tools is flexibility. Since these machines are run from programs, running a different workpiece is almost as easy as loading a different program. Once a program has been verified and executed for one production run, it can be easily recalled the next time the workpiece is to be run. This leads to yet another benefit, fast change-overs. Since these machines are very easy to setup and run, and since programs can be easily loaded, they allow very short setup time. This is imperative with today’s Just-In-Time product requirements.1. Motion control-the heart of CNCThe most basic function of any CNC machine is automatic, precise, and consistent motion. Rather than applying completely mechanicaldevices to cause motion as is required on most conventional machine tools, CNC machines allow motion control in a revolutionary manner. All forms of CNC equipment have two or more directions of motion, called axes. These axes can be precisely and automatically positioned alongtheir lengths of travel. The two most common axis types are linear (driven along a straight path) and rotary (driven along a circular path).Instead of causing motion by turning cranks and handwheels as is required on conventional machine tools, CNC machines allow motions to be commanded through programmed commands. Generally speaking, the motion type (rapid, linear, and circular), the axes to move, the amount of motion and the motion rate (feedrate) are programmable with almost all CNC machine tools.Accurate positioning is accomplished by the operator counting the number of revolutions made on the handwheel plus the graduations on the dial. The drive motor is rotated a corresponding amount, which in turn drives the ball screw, causing linear motion of the axis. A feedback device confirms that the proper amount of ball screw revolutions has occurred.A CNC command executed within the control (commonly through a program) tells the drive motor to rotate a precise number of times. The rotation of the drive motor in turn rotates the ball screw. And the ball screw causes drives the linear axis. A feedback device at the opposite end of the ball screw allows the control to confirm that the commanded number of rotations has taken place.Though a rather crude analogy, the same basic linear motion can be found on a common table vise. As you rotate the vise crank, you rotate a lead screw that, in turn, drives the movable jaw on the vise. By comparison, a linear axis on a CNC machine tool is extremely precise. The number of revolutions of the axis drive motor precisely controls the amount of linear motion along the axis.How axis motion is commanded-understanding coordinate systems. It would be infeasible for the CNC user to cause axis motion by trying to tell each axis drive motor how many times to rotate in order to command a given linear motion amount. (This would be like having to figure out how many turns of the handle on a table vise will cause the movable jaw to move exactly one inch!) Instead, all CNC controls allow axis motion to be commanded in a much simpler and more logical way by utilizing some form of coordinate system. The two most popular coordinate systems used with CNC machines are the rectangular coordinate system and the polar coordinate system. By far, the move popular of these two is the rectangular coordinate system, and we’ll use it for all discussions made during this presentation.。
科技文献中英文对照翻译
Human Geomatics in Urban Design—Two Case Studies在城市设计中的人类地理信息学——两个案例研究Małgorzata Hanzl1,*,Karol Dzik2,Paulina Kowalczyk2,Krystian Kwieciński2,Ewa Stankiewicz2and AgataŁ.Wierzbicka2Abstract:The mapping of different aspects of urban phenomena and their relation to thephysical cityscape has been greatly extended by the use of geomatics.The tradition to basereasoning on‗understanding the world‘dates from the time of Aristotle.The extensionplan for Barcelona(Eixample),developed by Cerdà,which opened the era of modern urbanplanning,was preceded by analyses of rich data,describing both detailed demographicissues and physical structures.The contemporary,postmodernist city planning continuesthis tradition,although a shift towards analyses of more human-related issues can beobserved,covering,inter alia,citizens‘perception,cultural differences and patterns ofhuman activities with regard to distinct social groups.The change towards a morehuman-related perspective and the inclusion of urban morphology analyses are directconsequences of this trend.The required data may be gathered within a crowd-sourcingparticipation process.According to communicative planning theory,communication withthe wider public is indispensable in order to achieve the best results,and can be realizedwith the use of sophisticated IT tools.Evidence-based reasoning may be supported byimages of significant aesthetic values,which inspire immediate reactions.Keywords:GIS;crowd-sourcing;mash-up;education;urban planning;urban analyses摘要：不同方面的城市现象及其与物理城市景观的关系映射经由地理信息学的使用已经大大扩展了。
科技类文章中英文对照范文带翻译
科技类文章中英文对照范文带翻译印度首富百亿美元建4G网免费向全国提供India's richest man is rolling out a $20 billion mobile network that could bring lightning-fast Internet to hundreds of millions of people.印度首富正斥资200亿美元建设移动网络，或可使十亿人高速连接互联网。
Indian consumers are already celebrating the arrival of Mukesh Ambani's new Reliance Jio service, seizing on the billionaire's promise to deliver rock bottom prices and download speeds thatwill enable streaming video.印度消费者已经在庆祝穆克什•安巴尼新推出的瑞来斯Jio网络服务。
这位亿万富翁承诺，该网络会以最低价格提供满足流媒体使用的下载速度。
The 4G network, which reaches more than 80% of the country, officially went live Monday with a set of generous introductory offers.这个覆盖印度超过80%地区的4G网络于周一正式开通，同时慷慨附送试用套餐。
Indians will be able to use Jio for free until the end of 2021, and pay as little as 149 rupees $2.25 a month for data after that.印度人到今年年底都可免费使用Jio网络，之后的网费也只有每月149卢比2.25美金。
英语科技文双语版
科技文1.单心室辅助人工心脏应用于实验动物山羊，存活11天又23小时。
在存活期间，动物心电图，中心静脉压，呼吸，体温等参数基本正常。
石泵分流量可调，驱动装置连续工作11天，性能稳定可靠。
动物死后的病理解剖表明，死亡的主要原因是肾动脉的广泛性血栓引起的急性肾功能衰竭。
A univentricular assistant artificial heart was applied to the experiment goat, which survived for 11 days and 23 hours. During the period of survival, the parameters such as E.C.G., central venous blood pressure, respiration and temperature appeared to be essentially normal. The necessary amount of blood flow was well regulated by the pump. The driving system worked continuously, smoothly and reliably for 11 days. Postmortem patho-anatomy revealed that the chief cause of the animal’s death was acute renal failure as a result of widespread multiple embolism of renal arteries.2. 中国已经成功地发射了第一颗试验通信卫星。
这颗卫星是由三级火箭推动的，一直运转正常。
它标志着我国运载工具和电子技术方面进入了一个新阶段。
The successful launching of China’s first experimental communication satellite, which was propelled by a three-stage rocket and has been in operation ever since, indicates that our nation has entered a new stage in the development of carrier rockets and electronics.3.石墨晶体结构遭到破坏时，总是碎化为微小尺寸的片状粉末。
科技文翻译英汉对照
Ross Gregory WRc Swindon Frankland Road,Blagrove Swindon,Wiltshire England罗斯格雷戈里斯文顿弗兰克兰路,布拉格罗夫斯温顿英格兰，威尔特郡Thomas F. Zabel WRc Medmenham Medmenham,Oxfordshire England托马斯·f·扎贝尔汽车拉力英格兰牛津郡James K. Edzwald Professor,Department of Civil and Environmental Engineering University of Massachusetts Amherst,Massachusetts U.S.A.詹姆斯·k.爱德华教授,土木与环境工程系马萨诸塞大学阿默斯特,美国马萨诸塞州Sedimentation and flotation are solid-liquid separation processes used in water treatment mostly to lower the solids concentration,or load,on granular filters. As a result,filters can be operated more easily and cost effectively to produce acceptablequality filtered water. Many sedimentation and flotation processes and variants of them exist, and each has advantages and disadvantages. The most a ppropriate process for a particular application will depend on the water to be treated as well as local circumstances and requirements.水处理中的固液分离过程中使用沉降和浮选流程主要是为了降低固体颗粒浓度、颗粒过滤器或负载。
英文科技文献以及翻译
科技翻译原文题目：Struts In Action译文题目：支杆的应用指导教师：邱保志职称：教授学生姓名：郑豪学号：20137670459专业：计算机科学与技术（软件方向）院（系）：信息工程学院完成时间：2017年5月30日Struts In Action1What is struts (2)2Who makes the Struts software (2)2.1Why is Struts open source (2)2.2Why is it called Struts (3)3What are application frameworks (3)3.1Other types of frameworks (3)3.2Enabling technologies (4)3.2.1Hypertext Transfer Protocol(HTTP) (4)3.2.2Common Gateway Interface(CGI) (5)3.2.3Java servlets (6)3.2.4JavaServer Pages (6)3.3Enabling technologies11 (7)3.4.1JSP tags (7)3.4.1JavaBeans (8)3.4Enabling technologies111 (9)4Struts from30,000feet (10)1What is strutsStruts is open source software that helps developers build web applicationsquickly and easily.Struts relies on standard technologies—such as JavaBeans,Javaservlets,and Java Server Pages(JSP)—that most developers already know how touse.By taking a standards-based,“fill-in-the-blanks”approach to software development,Struts can alleviate much of the time-consuming grunt work that comeswith every new project.2Who makes the Struts softwareStruts is hosted by the Apache Software Foundation(ASF)as part of its Jakartaproject. Besides Struts,Jakarta hosts several successful open source products,including Tomcat, Ant,and Velocity.The initial Struts codebase was developed between May2000and June 2001when version1.0was released.More than30developers contributed to the Struts distribution,and thousands more follow the Struts mailing lists.The Struts codebase is managed by a team of volunteer“Committers.”By2002,the Struts team included nine active Committers.The primary architect and developer of the Struts framework is Craig R.McClanahan.Craig is also the primary architect of Tomcat4and the implementationarchitect of the Java Web Services Developer Pack.He is now Sun’s specification lead for JavaServer Faces(JSR-127)as well as the Web Layer Architect for the Java2Enterprise Edition(J2EE)platform.Struts is available to the public at no charge under the Apache Software License[ASF,License].There are no acquisition or other recurring costs for using the software.Unlike some other open source licenses,the Apache Software License is business-friendly.You can use Struts to create a commercial project and distribute the Struts binary without any red tape,fees,or other hassles.You can also integrate the Struts components into your own framework just as if they were written in-house.For complete details,see the Apache Software License at/LICENSE.2.1Why is Struts open sourceMost of the leading Java utilities and frameworks are now open source projects.Many of the developers working on these projects do so as part of their regular jobs with companies like IBM,Sun Microsystems,and Apple.Collaborating openly on this type of software benefits the entire marketplace.Today,many open source components are integrated into commercial panies then sell professional documentation, guaranteed support levels,and other valuable aftermarket services to their clients.When software is freely available,it becomes much easier for the marketplace to support.Strutsis a prime example of this.Although still a youngster,it has already been featured in dozens of articles and seminars,not to mention books like this one.Many development teams do not like to use software that was not“invented”in-house.Open source components provide all the benefits of writing the same software in-house but do not lock you into a proprietary solution that only your team understands.Open source frameworks are a win-win for everyone.2.2Why is it called StrutsThe framework is called“Struts”to remind us of the invisible underpinnings that hold up our houses,buildings,bridges,and,indeed,ourselves when we are on stilts.This is an excellent description of the role Struts plays in developing web applications.When raising physical structures,construction engineers use struts to provide support for each floor of a building.Likewise,software engineers use Struts to support each layer of a business application.3What are application frameworksA framework is a reusable,semi-complete application that can be specialized to produce custom applications[Johnson].Like people,software applications are more alike than they are different.They run on the same computers,expect input from the same devices, output to the same displays,and save data to the same hard disks.Developers working on conventional desktop applications are accustomed to toolkits and development environments that leverage the sameness between applications.Application frameworks build on this common ground to provide developers with a reusable structure that can serve as the foundation for their own products.A framework provides developers with a set of backbone components that have the following characteristics:_They are known to work well in other applications._They are ready to use with the next project._They can also be used by other teams in the organization.Frameworks are the classic build-versus-buy proposition.If you build it,you will understand it when you are done—but how long will it be before you can roll your own?If you buy it,you will have to climb the learning curve—and how long is that going to take? There is no right answer here,but most observers would agree that frameworks such as Struts provide a significant return on investment compared to starting from scratch, especially for larger projects.3.1Other types of frameworksThe idea of a framework applies not only to applications but to application components as well.Throughout this book,we introduce other types of frameworks that you can use withStruts.These include the Lucene search engine,the Scaffold toolkit,the Struts validator, and the Tiles tag library.Like application frameworks,these tools provide semi-complete versions of a subsystem that can be specialized to provide a custom component.Some frameworks have been linked to a proprietary development environment.This is not the case with Struts or any of the other frameworks shown in this book.You can use any development environment with Struts:Visual Age for Java,JBuilder,Eclipse,Emacs,and Textpad are all popular choices among Struts developers.If you can use it with Java,you can use it with Struts.3.2Enabling technologiesApplications developed with Struts are based on a number of enabling technologies.These components are not specific to Struts and underlie every Java web application.A reason that developers use frameworks like Struts is to hide the nasty details behind acronyms like HTTP,CGI,and JSP.As a Struts developer,you don’t need to be an alphabet soup guru,but a working knowledge of these base technologies can help you devise creative solutions to tricky problems.3.2.1Hypertext Transfer Protocol(HTTP)When mediating talks between nations,diplomats often follow a formalprotocol.Diplomatic protocols are designed to avoid misunderstandings and to keep negotiations from breaking down.In a similar vein,when computers need to talk,they also follow a formal protocol.The protocol defines how data is transmitted and how to decode it once it arrives.Web applications use the Hypertext Transfer Protocol(HTTP)to move data between the browser running on your computer and the application running on the server.Many server applications communicate using protocols other than HTTP.Some of these maintain an ongoing connection between the computers.The application server knows exactly who is connected at all times and can tell when a connection is dropped. Because they know the state of each connection and the identity of each person using it, these are known as stateful protocols.By contrast,HTTP is known as a stateless protocol. An HTTP server will accept any request from any client and will always provide some type of response,even if the response is just to say no.Without the overhead of negotiating and retaining a connection,stateless protocols can handle a large volume of requests. This is one reason why the Internet has been able to scale to millions ofcomputers.Another reason HTTP has become the universal standard is its simplicity.An HTTP request looks like an ordinary text document.This has made it easy for applications to make HTTP requests.You can even send an HTTP request by hand using a standard utility such as Telnet.When the HTTP response comes back,it is also in plain text that developers can read.The first line in the HTTP request contains the method,followed by the location of the requested resource and the version of HTTP.Zero or more HTTP request headers follow the initial line.The HTTP headers provide additional information to the server.This can include the browser type and version,acceptable document types,and the browser’s cookies,just to name a few.Of the seven request methods,GET and POST are by far the most popular.Once the server has received and serviced the request, it will issue an HTTP response.The first line in the response is called the status line and carries the HTTP protocol version,a numeric status,and a brief description of the status. Following the status line,the server will return a set of HTTP response headers that work in a way similar to the request headers.As we mentioned,HTTP does not preserve state information between requests.The server logs the request,sends the response,and goes blissfully on to the next request.While simple and efficient,a stateless protocol is problematic for dynamic applications that need to keep track of their users.(Ignorance is not always bliss.)Cookies and URL rewriting are two common ways to keep track of users between requests.A cookie is a special packet of information on the user’s computer.URL rewriting stores a special reference in the page address that a Java server can use to track users.Neither approach is seamless,and using either means extra work when developing a web application.On its own,a standard HTTP web server does not traffic in dynamic content.It mainly uses the request to locate a file and then returns that file in the response.The file is typically formatted using Hypertext Markup Language(HTML)[W3C, HTML]that the web browser can format and display.The HTML page often includes hypertext links to other web pages and may display any number of other goodies,such as images and videos.The user clicks a link to make another request,and the process begins anew.Standard web servers handle static content and images quite well but need a helping hand to provide users with a customized,dynamic response.DEFINITION Static content on the Web comes directly from text or data files,like HTML or JPEG files.These files might be changed from time to time,but they are not altered automatically when requested by a web browser.Dynamic content,on the other hand,is generated on the fly,typically in response to an individualized request from a browser.3.2.2Common Gateway Interface(CGI)The first widely used standard for producing dynamic content was the Common Gateway Interface(CGI).CGI uses standard operating system features,such as environment variables and standard input and output,to create a bridge,or gateway,between the web server and other applications on the host machine.The other applications can look at the request sent to them by the web server and create a customized response.When a web server receives a request that’s intended for a CGI program,it runs that program and provides the program with information from the incoming request.The CGI program runs and sends its output back to the server.The web server then relays the response to the browser.CGI defines a set of conventions regarding what information it will pass as environment variables and how it expects standard input and output to be used.Like HTTP, CGI is flexible and easy to implement,and a great number of CGI-awareprograms have been written.The main drawback to CGI is that it must run a new copy of the CGI-aware program for each request.This is a relatively expensive process that can bog down high-volume sites where thousands of requests are serviced per minute. Another drawback is that CGI programs tend to be platform dependent.A CGI program written for one operating system may not run on another.3.2.3Java servletsSun’s Java Servlet platform directly addresses the two main drawbacks of CGI programs.First,servlets offer better performance and utilization of resources than conventional CGI programs.Second,the write-once,run-anywhere nature of Java means that servlets are portable between operating systems that have a Java Virtual Machine (JVM).A servlet looks and feels like a miniature web server.It receives a request and renders a response.But,unlike conventional web servers,the servlet application programming interface(API)is specifically designed to help Java developers create dynamic applications.The servlet itself is simply a Java class that has been compiled into byte code,like any other Java object.The servlet has access to a rich API of HTTP-specific services,but it is still just another Java object running in an application and can leverage all your other Java assets.To give conventional web servers access to servlets,the servlets are plugged into containers.The servlet container is attached to the web server. Each servlet can declare what URL patterns it would like to handle.When a request matching a registered pattern arrives,the web server passes the request to the container, and the container invokes the servlet.But unlike CGI programs,a new servlet is not created for each request.Once the container instantiates the servlet,it will just create a new thread for each request.Java threads are much less expensive than the server processes used by CGI programs.Once the servlet has been created,using it for additional requests incursn very little overhead.Servlet developers can use the init() method to hold references to expensive resources,such as database connections or EJB Home Interfaces,so that they can be shared between requests.Acquiring resources like these can take several seconds—which is longer than many surfers are willing to wait.The other edge of the sword is that,since servlets are multithreaded,servlet developers must take special care to be sure their servlets are thread-safe.To learn more about servlet programming,we recommend Java Servlets by Example,by Alan R.Williamson [Williamson].The definitive source for Servlet information is the Java Servlet Specification [Sun,JST].3.2.4JavaServer PagesWhile Java servlets are a big step up from CGI programs,they are not a panacea.To generate the response,developers are still stuck with using println statements to render the HTML.Code that looks likeout.println("<P>One line of HTML.</P>");out.println("<P>Another line of HTML.</P>");is all too common in servlets that generate the HTTP response.There are libraries that can help you generate HTML,but as applications grow more complex,Java developers end up being cast into the role of HTML page designers.Meanwhile,given the choice,most project managers prefer to divide development teams into specialized groups.They like HTML designers to be working on the presentation while Java engineers sweat the business ing servlets alone encourages mixing markup with business logic,making itdifficult for team members to specialize.To solve this problem,Sun turned to the idea of using server pages to combine scripting and templating technologies into a single component.To build Java-Server Pages,developers start by creating HTML pages in the same old way,using the same old HTML syntax.To bring dynamic content into the page, the developer can also place JSP scripting elements on the page.Scripting elements are tags that encapsulate logic that is recognized by the JSP.You can easily pick out scripting elements on JSP pages by looking for code that begins with<%and ends with%>.For instance,to display the last modified date on the page,the developer would place the following code in the page:<B>This page was accessed at<%=new Date()%></B>There are three different types of scripting elements:expressions,scriptlets,and declarations,as shown in table1.1.Table1.1JSP scripting elementsElement PurposeExpressions Java code,bound by<%=and%>,used to evaluate Java language statements andinsert the result into the servlet’s outputScriptlets Java code,bound by<%and%>,often used to create dynamic content Declarations Java code,bound by<%!and%>,used to add code to the body of the servlet class3.3Enabling technologies11To be seen as a JSP page,the file just needs to be saved with an extension of.jsp.When a client requests the JSP page,the container translates the page into a source code file for a Java servlet and compiles the source into a Java class file—just as you would do if you were writing a servlet from scratch.At runtime,the container can also check the last modified date of the JSP file against the class file.If the JSP file has changed since it was last compiled,the container will retranslate and rebuild the page all over again.Project managers can now assign the presentation layer to HTML developers,who then pass on their work to Java developers to complete the business-logic portion.The important thing to remember is that a JSP page is really just a servlet.Anything you can do with a servlet, you can do with a JSP.3.3.1JSP tagsScripting elements are only one of the two ways to generate dynamic JSP content. Scriptlets are quick,easy,and powerful but require that developers mix Java code with HTML.Experience has taught us that embedding logic into JSP pages leads tonon-maintainable applications with minimal opportunity for reuse.A popular alternative is to use JSP tags.JSP tags are mixed in with the HTML markup and can be used as if they were ordinary HTML tags.A single JSP tag may represent dozens of Java statements,but all the developer needs to know is to how to insert the tag.The programming code is hidden away in a Java class file.To use the same code on another page,the developer only has to insert the tag markup again.If the code for the tag changes,all the tags willautomatically use the updated version.The JSP page using the tag does not need to be revised.JSP tags provide much better reuse than scriptlets and can be easier for page developersJSPs vs.ASPsMicrosoft and Sun both offer their own brand of server pages.Sun offers JavaServer Pages and Microsoft offers Active Server Pages(ASP).Both JSP s and ASPs are designed so that developers can create dynamic web pages customized with back-office data.While similar on the surface,there are several differenc es between ASP s and JSP s:_ JSP s are platform independent—write once,run anywhere._Developers have input to the direction of JSP s through the Java Community Process(JCP)._JSP developers can extend the JSP tag set with custom tags._JavaBeans and Enterprise JavaBeans(EJB)can be used with JSP s to increase reusability and reduce maintenance._JSPs can access many other Java libraries,including Java Database Connectivity(JDBC),Java Mail,Java Message Service(JMS),and Java Naming and Directory Interface(JNDI)._JSP s are compiled into a binary class file and do not need to be interpreted for every request._JSP s find wide support with tool vendors,containers,and web servers.to use, since they look like the familiar HTML tags.A number of prebuilt JSP tags libraries are available that will perform useful functionality for developers.Among these is the new JSP Standard Tag Library(JSTL).This new standard provides a rich library of reusable JSP tags.For more on JSTL,we highly recommend JSTL in Action,by Shawn Bayern[Bayern]. Struts works well with JSTL and other publicly available tag libraries,as well as any you might write yourself.For more on JSP and JSP pages,we highly recommend Web Development with JavaServer Pages,by Duane K.Fields,Mark A.Kolb,and Shawn Bayern[Fields].The definitive source for JSP information is the JavaServer Pages Specification[Sun,JSP].JSP pages are an integral part of the Struts developer’s toolbox. Most Struts developers use JSP pages and custom tags to create all the dynamic content for their applications.3.3.2JavaBeansJavaBeans are Java classes which conform to a set of design patterns that make them easier to use with development tools and other components.DEFINITION A JavaBean is a reusable software component written in Java.To qualify as a JavaBean,the class must be concrete and public,and have a noargument constructor. JavaBeans expose internal fields as properties by providing public methods that follow a consistent design pattern.Knowing that the property names follow this pattern,other Java classes are able to use introspection to discover and manipulate JavaBean properties. Rolling your own1Create a class that implementsjavax.servlet.jsp.tagext.TagSupportor javax.servlet.jsp.tagext.BodyTagSupport by implementing the doStart()or doEnd()method.These methods obtain a JspWriter object to write out any valid HTML content you need.2Create a tag library descriptor(TLD)file to map the classes you just created to a JSP tag name.3Define your<taglib>elements in the web application descriptor file(web.xml).Tell the JSP page that you will be using your tags by placing a@taglib statement at the top of the page:<%@taglib uri="/tags/app.tld prefix="app"%>4This statement imports the library for use on this page and assigns it a tag prefix.For more,see the JSP Tag Library technology page.3.4Enabling technologies111The JavaBean design patterns provide access to the bean’s internal state through two flavors of methods:accessors are used to read a JavaBean’s state;mutators are used to change a JavaBean’s state.Mutators are always prefixed with lowercase token set followed by the property name.The first character in the property name must be uppercase.The return value is always void—mutators only change property values;they do not retrieve them.The mutator for a simple property takes only one parameter in its signature,which can be of any type.Mutators are often nicknamed setters after their prefix.The mutator method signature for a weight property of the type Double would be public void setWeight(Double weight)A similar design pattern is used to create the accessor method signature.Accessor methods are always prefixed with the lowercase token get,followed by the property name.The first character in the property name must be uppercase.The return value will match the method parameter in the corresponding mutator.Accessors for simple properties cannot accept parameters in their method signature.Not surprisingly, accessors are often called getters.The accessor method signature for our weight property is public Double getWeight()If the accessor returns a logical value,there is a variant pattern. Instead of using the lowercase token get,a logical property can use the prefix is,followed by the property name.The first character in the property name must be uppercase.The return value will always be a logical value—either boolean or Boolean.Logical accessors cannot accept parameters in their method signature.The boolean accessor method signature for an on property would be public boolean isOn()The canonical method signatures play an important role when working with Java-Beans.Other components are able to use the Java Reflection API to discover a JavaBean’s properties by looking for methods prefixed by set,is,or get.If a component finds such a signature on a JavaBean,it knows that the method can be used to access or change the bean’s properties.Sun introduced JavaBeans to work with GUI components,but they are now used with every aspect of Java development,including web applications.When Sun engineers developed the JSP tag extension classes,they designed them to work with JavaBeans.The dynamic data for a page can be passed as a JavaBean,and the JSP tag can then use the bean’s properties to customize the output.For more on JavaBeans,we highly recommend The Awesome Power of JavaBeans,by Lawrence H.Rodrigues[Rodrigues].The definitive source for JavaBean information is the JavaBean Specification[Sun,JBS].Model2The0.92release of the Servlet/JSP Specification described Model2as an architecture that uses servlets and JSP pages together in the same application.The term Model2 disappeared from later releases,but it remains in popular use among Java web developers.Under Model2,servlets handle the data access and navigational flow,while JSP pages handle the presentation.Model2lets Java engineers and HTML developers each work on their own part of the application.A change in one part of a Model2 application does not mandate a change to another part of the application.HTML developers can often change the look and feel of an application without changing how the back-office servlets work.The Struts framework is based on the Model2architecture.It provides a controller servlet to handle the navigational flow and special classes to helpwith the data access.A substantial custom tag library is bundled with the framework to make Struts easy to use with JSP pages.4Struts from30,000feetHold on to your hats!Now that we’ve covered the basics,it’s time for a whirlwind tour of Struts.Before we try to get into the nuts and bolts of the framework components,let’s start with the big picture.Struts uses a Model2architecture.The Struts ActionServlet controls the navigational flow.Another Struts class,the Action,is used to access the business classes.When the ActionServlet receives a request from the container,it uses the URI(or “path”)to determine which Action it will use to handle the request.An Action can validate input and access the business layer to retrieve information from databases and other data services.To validate input or use the input to update a database,the Action needs to know what values were submitted.Rather than force each Action to pull these values out of the request,the ActionServlet bundles the input into a JavaBean.The input beans are subclasses of the Struts ActionForm class.The ActionServlet can determine which ActionForm to use by looking at the path of the request,in Struts from30,000feet15the same way the Action was selected.An ActionForm extendsorg.apache.struts.action.ActionForm.Each HTTP request must be answered with an HTTP ually,a Struts Action does not render the response itself but forwards the request on to another resource,such as a JSP page.Struts provides an ActionForward class that can be used to store the path to a page under a logical name.When it has completed the business logic,the Action selects and returns an ActionForward to the servlet.The servlet then uses the path stored in the ActionForward object to call the page and complete the response.Struts bundles these details together into an ActionMapping object.Each ActionMapping is related to a specific path.When that path is requested,the servlet retrieves the ActionMapping object.The mapping tells the servlet which Actions, ActionForms,and ActionForwards to use.All of these details,the Actions,ActionForms, ActionForwards,ActionMappings,and some other things,are declared in thestruts-config.xml file.The Action-Servlet reads this file at startup and creates a database of configuration objects.At runtime,Struts refers to the objects created with the configuration file,not the file itself.Figure1.illustrates how these components fit together.Believe it or not,you already know enough about Struts to assemble a simple application.It won’t do much,but it will illustrate how Struts actually works.Figure1Struts from30,000feetBelieve it or not,you already know enough about Struts to assemble a simple application. It won’t do much,but it will illustrate how Struts actually works.。
《科技英语文献阅读与翻译》Unit 1-TextB
made it hard for the president candidate to fall asleep. 2) to join as spouses, marry eg: Falling in love at the first sight, they coupled as a perfect match.
promotion. (The) chances are (that)…: It is likely that… eg: Chances are they’ll be intent on leaving for
As the Internet and other forms of electronic communication become more prevalent, electronic security is also becoming increasingly important. Cryptography is used to protect e-mail messages, credit card information, and corporate data.
eavesdrop v. listen secretly to private conversation of others
科技英语中英文对照翻译
mobile and cellular radio移动和细胞广播in comparison to the relative stability and modest technical developments which are occurring in long haul wideband microwave communication systems there is rapid development and expanding deployment of new mobile personal communication system. These rang from wide coverage area pagers,for simple data message transmission,which employ common standards and hence achieve contiguous coverage over large geographical areas,such as all the major urban centres and transport routes in Europe,Asia or the continental USA.This chapter discusses the special channel characteristics of mobile systems and examines the typical cellular clusters adopted to achieve continuous communication with the mobile user.It then highlights the important properties of current,and emerging,TDMA and code division multiple access(CDMA), mobile digital cellular communication systems.Private mobile radioTerrestrial mobile radio works best at around 250 MHz as lower frequencies than this suffer from noise and interference while higher frequencies experience multipath propagation from buildings,etc,section 15.2.In practice modest frequency bands are allocated between 60MHz and 2GHz. Private mobile radio(PMR) is the system which is used by taxi companies,county councils,health authorities,ambulance services,fire services,the utility industries,etc,for mobile communications.PMR has three spectral at VHF,one just below the 88 to 108 MHz FM broadcast band and one just above this band with another allocation at approximately 170MHz.There are also two allocations at UHF around 450MHz. all these spectral allocations provide a total of just over 1000 radio channels with the channels placed at 12KHz channel spacings or centre frequency offsets. Within the 12khz wide channal the analogue modulation in PMR typically allows 7khz of bandwidth for the signal transmission.when further allowance is made for the frequency drift in the oscillators of these systems a peak deviation of only 2 to 3 khz is available for the speech traffic. Traffic is normally impressed on these systems by amplitude modulation or frequency modulation and again the receiver is of the ubiquitous superheterodyne design,Figure 1.4. A double conversion receiver with two separate local oscillator stages is usually required to achieve the required gain and rejection of adjacent channel signals.One of the problems with PMR receiver is that they are requiredto detect very small signals,typically—120dBm at the antenna output,corresponding to 0.2 uV,and,after demodulating this signal,produce ann output with perhaps 1W of audio equipment, the first IF is normally at10.7MHz and the second IF is very orten at 455KHz . unfortunately,with just over 1000 available channels for the whole of the UK and between 20000and30000issued licences for these systems,it is inevitable that the average busuness user will have to share the allocated channel with other companies in their same geographical area.There are various modes of operation for mobile radio communications networks, the simplest of which is singal frequency simplex. In simplex communication, traffic is broadcast, or one way. PMR uses half duplex(see later Table 15.3) where, at the end of each transmission period, there is a handover of the single channel to the user previously receiving, in order to permit them to reply over the same channel. This is efficient in that it requires only one frequency allocation for the communication link but it has the disadvantage that all units canhear all transmissions provided they are within rage of the mobile and frequencies are allocated for the transmissions. One frequency is used for the forward or downlink, namely base-to-mobile communications. This permits simultaneous two-way communication and greatly reduces the level of interference, but it halves other’s transmissions, which can lead to contention with two mobiles attempting to initiate a call, at the same time, on the uplink in a busy syetem.Although PMR employs relatively simple techniques with analogue speech transmission there have been many enhancements to these systems over the years . Data transmission is now in widespread use in PMR systems using FSK modulation. Data transmission also allows the possibility of hard copy graphics output and it gives direct access to computer services such as databases, etc. Data prembles can also be used, in a selective calling mode, when initiating a transmission to address a special receiver and thus obtain more privacy within the system.15.4.5 Trunked radio for paramilitary use集群无线电的军事使用Another related TDMA mobile radio standard is the European trunked radio(TETRA)network which has been developed as part of the public safety radio communications service(PSRCS) for use by police, utilities, customs office, etc. TETRA in fact is part of wider international collaborations for paramilitary radio use.In these portable radios there is a need for frequency hopping (FH) to give an antieavesdropping capability and encryption for security of transmission to extend military mobile radio capabilities to paramilitary use, i.e. for police, customs and excise offices, etc. these capabilities are included in the multiband interteam radio for the associated public safety communications office in the USA while Europe has adopted the TETRA standard.TETRA is essentially the digital TDMA replacement of the analogue PMR systems. The TETRA standard has spectrum allocations of 380 to 400 and 410 to 430MHz, with the lower band used for mobile transmissions and the upper band for base station use. TETRA mobile have 1 W output power and the base stations 25 W using error with the data throughput rate varying, to meet the required quality of service. TETRA can accommodate up to four users each with a basic speech or data rate of 7.2kbit/s. with coding and signaling overheads, the final transmission rate for the four-user slot is 36 kbit/s. this equipment is large and more sophisticated than a commercial cell phone, and it sells for a very much higher price becase the production runs are much small. However, its advanced capabilities are essential for achieving paramilitary communications which are secure from eavesdropping.15.5 Code division multiple accessAnalogue communication systems predominantly adopt frequency division multiple access (FDMA), where each subscriber is allocated a narrow frequency slot within the available channel. The alternative TDMA(GSM) technique allocates the entire channel bandwidth to a subscriber but constrains the subscriber but constrains the subscriber to transmit only regular short bursts of wideband signal. Both these accessing techniques are well established for long haulterrestrial, satellite and mobile communications as they offer very good utilization of the available bandwidth.15.5.1The inflexibility of these coordinated accessing techniques has resulted in the development of new systems based on the uncoordinated spread spectrum concept. In these systems the bits of slow speed data traffic from each subscriber are deliberately multiplied by a high chip rate spreading code, forcing the low rate (narrowband data signal) to fill a wide channel bandwidth.15.7.2 3G systemsThe evolution of the third generation (3G)system began when the ITU produce the initial recommendations for a new universal mobile telecommunications system(UMTS)[www.] The 3G mobile radio service provides higher data rate services ,with a maximum data rate in excess of 2Mbit/s, but the achievable bit rate is linked to mobility. Multimedia applications encompass services such as voice, audio/video, graphics, data, Internet access and e-mail. These packet and circuit switched services have to be supported by the radio interface and the network subsystem.Several radio transmission technologies(RTT) were evaluated by the ITU and adopted into the new standard, IMT-2000. the European standardization body for 3G, the ETSI Special Mobile Group, agreed on a radio access scheme for 3G UMTS universal terrestrial radio access(UTRA) as an evolution of GSM. UTRA consists of two modes : frequency division duplex(FDD) where the uplink and downlink are transmitted on different frequencies; and time division duplex(TDD) where the uplink and downlink are time multiplexed onto the same carrier frequency. The agreement assigned the unpaired bands (i.e. for UTRA TDD ). TD-CDMA is a pure CDMA based system. Both modes of UTRA have been harmonised with respect to basic system parameters such as carrier spacing, chip rate and frame length to ensure the interworking of UTRA with GSM.The 3G proposal were predominantly based wideband CDMA(WCDMA) and a mix of FDD and TDD access techniques. WCDMA is favoured for 3G in poor propagation environments with a mix of high modest speed data traffic. It is generally accepted that CDMA is the preferred accesstechnique and, with the increase in the data rate, then the spreading modulation needs to increase to wideband transmission.WCDMA is based on 3.84Mchip/s spreading codes with spreading ratio, i.e. , K values, of 4-256 giving corresponging data ratas of 960-15 kbit/s. the upper FDD uplink band I from 1920-1980 MHz is paired with a 2110-2170 MHz downlink. In addition uplink bands II & III at 1850-1910 MHz and 1710-1785 MHz are also paired, respectively, with 1930-1990 MHz and 1805-1880 MHz allocations. the system is configured on a 10 ms frame with 15 individual slots to facilitate TDD as well as FDD transmissions. TDD is more flexible as time-slots can be dynamically reassigned to uplink and downlink functions, as required for asymmetric transfer of large files or video on demand traffic. 3G WCDMA systems use an adaptive multirate speech coder with encoded rates of 4.75-12.2 kbit/s. receivers commonly use the easily integrated direct conversion design, in place of the superheterodyne design . receiver sensitivities are typically -155dBm.The 3GPP2 standard aims to achieve a wide area mobile wireless packet switched capability with CDMA2000 1×EV DO revision A (sometimes called IS-856A). Here 1×refers to the single carrier 1.25 Mchip/s system. It achieves a 3.1 Mbit/s downlink and a delay sensitive services. The 3GPP standard has gone through many release with R4 in 2001 which introduced packet data services and R6 in 2005 to further increase the available data transmission rate . R6 pioneers the use of high-speed downlink packet access and multimedia broadcast multicast services which offer reduced delays and increased uplink data rates approaching 6 Mbit/s.In parallel with the European activities extensive work on 3G mobile radio was also performed in Japan. The Japanese standardisation body also chose WCDMA, so that the Japanese and European proposals for the FDD mode were already aligned closely. Very similar concepts have also been adopted by the North American standardization body.In order to work towards a global 3G mobile radio standard, the third generation partnership project(3GPP), consisting of members of the standardization bodies in Europe, the USA, Japan, Korea and China, was formed. It has merged the already well harmonized proposals of the regional standardization bodies to work on a common 3G international mobile radio standard, still called UTRA. The 3GPP Project 2(3GPP2), on the other hand, works towards a 3G mobile radio standard based on cdmaOne/IS-95 evolution, originally called CDMA2000.比起相对稳定、适度的技术发展是发生在宽带微波通信系统,有长期快速发展和扩大部署的新的移动个人通讯系统。
英文文献科技类原文及翻译39
英文文献科技类原文及翻译39摘要：讨论了一种具有普遍运用前景的指纹IC卡电子门禁系统，引见了其设计方案、系统的总线结构以及单片机控制局部的软、硬件完成。
该系统将成熟的指纹生物识别技术和IC卡技术严密结合在一同，很好地处置了门禁系统中的身份认证效果和纸质门票带来的方便，具有很强的灵敏性、牢靠性和平安性，十分适宜于大型景色区等公共场所的门禁管理。
关键词：指纹门禁，智能卡，指纹识别，单片机关于一票制而需屡次进入的地铁、旅游胜地入口等场所，传统的纸质售票方式曾经越来越不适用于各部门管理的要求，停止计算机电子门票管理是社会开展的大势所趋。
其中入口处的身份认证是门禁管理的中心任务。
在现行的许多计算机系统中，用户的身份认证大都运用"用户ID+密码"的方法。
实践上，这种方法隐含着密码易遗忘、可传递、易被他人窃盗用等平安效果，同时在入口处需求密码输入不适宜人流量较大的公共场所，因此在电子门禁中需求一种更为便捷牢靠的身份认证方案。
针关于上述效果，本文讨论了一种已研制成功的基于成熟的指纹生物识别技术和IC卡技术的电子门禁系统，它具有"人卡合一"的功用，方便牢靠地停止入口身份认证，十分便于部门管理。
1 门禁系统总体方案1.1"人卡合一"的设计思绪生物识别技术是一种依据人类的生理特征(指纹、声响、面孔、虹膜等)来停止团体身份认证的辩识技术。
近年来，随着信息产业的开展，生物识别技术在国际外失掉了越来越普遍的研讨和运用。
其中指纹自动识别技术是当今开展最成熟的一种生物识别技术，指纹作为人体生物识别的一种方式，它具有以下几个清楚的优点：(1)确定性：每个指纹在人六个月的时分构成，以后终身不会改动，即使被划伤、烧伤，只需不伤及真皮，都不会改动他的指纹外形。
(2)独一性：两个完全一样的指纹出现的概率十分小，不超越600亿分之一。
(3)取样复杂：只需一个电容或光学的指纹采集器就可采集指纹图像。
科技文献的汉译英
“One belt one road” initiative is raised by China, but it belongs to the whole world. Party General Secretary Xi Jinping pointed out ,“One belt one road” initiative is based on the precious enlightenment from the ancient Chinese silk road, focusing on the common dream of the people on peace and development, and it has provided the world with a scheme for realization of common development and prosperity with Chinese wisdom. “The belt and road” initiative not only echoes the appeal of countries along the route but also reflects reasonable appeals of the countries along the route about reconstruction of the global administrative system, and it is a new starting point for China and the countries alone the route to build their dreams , hand in hand.“The belt and road” initiative is a new carrier for promotion of a more equal and inclusive globalization. Economy globalization is a sword with double edges, on one side, it provides strong momentum for global development and on the other side, it brings up some new situations and challenges, with which we should face thoroughly. We should get adapted to and guide the economy globalization, eliminate negative impacts and bring more benefit to all countries, nations along the route. “The belt and road” initiative is the best illustration on the promotion of an equal and inclusive globalization by China. Countries along the route of “The belt and road” initiative are mainly developing countries and newly emerged economies, and they are a lot different in terms of basic conditions, i.e., their infrastructure, resource exploitations, industry development levels, and China’s experience from reform and opening up could provide rich nutrition to “The belt and road “initiative, and its experiences on industry parks, economy corridors and industry conversion and upgrading is attractive to most of the developing countries.“The belt and road” initiative focuses on shared business, shared construction and benefit sharing without any political conditions, and it’s not a solo of a particular country but welcomes the participation of many countries along the route. All countries alone the route of “The belt and road” initiative, big or small, strong or weak could all participate in the initiative in equal position, give full play to economy compensation nd the achievement could be shared through cooperation, which showshow basically different “The belt and road ”initiative is compared to the Marshall Plan. China hopes that globalized development with inclusiveness could be realized through “The belt and road” initiative and make all countries along the route rich and make fortune for all people of the countries along the route of “The belt and road” initiative.“The belt and road” initiative is a try-out for “improvement of the global economy and political administrative system. As to the current system, the international trade rules and institution arrangement had been formed gradually after the 2nd world war, and western countries presented by the United States have long been on the absolute leading position. After entering the new ear, the global structure experienced profound changes, the focus of global economy has transferred and many emerging markets and developing countries presented by China has become stronger, the global economy and political administration should also keep pace with the time and change with the time, and shall be based on equality, reflect the new situation of international economy structure by enhancing the right to speak of newly emerging market countries, make sure that every country enjoy equal rights in international cooperation, and enjoy equal opportunities based on equal rules. “The belt and road” initiative is a major practice of China in participation in global economy administration in an active role, and is also an embodiment of China’s devotion on maintaining global peace, promotion of common development. Chia will stick to the principle of making neighbors comfort, feel at ease and rich and will continue hold up high the philosophy of intimacy, sincerity, benefit and inclusiveness, and open to share with all countries the achievement from the reform and opening up as well as the benefit from economy development in China.。
英文文献科技类天线的性能原文及翻译
目录1 天线的性能 (1)1.1天线辐射 (2)1.2增益 (3)1.3有效面积 (6)1.4路径损耗 (6)1.5雷达距离方程和截面 (8)1.6为什么要使用一个天线？ (10)2 PROPERTIES OF ANTENNAS (11)2.1 ANTENNA RADIATION (12)2.2GAIN (14)2.3EFFECTIVE AREA (17)2.4PATH LOSS (17)2.5RADAR RANGE EQUATION AND CROSS SECTION (19)2.6WHY USE AN ANTENNA? (22)1 天线的性能一个方法是一本有关天线的书是从讨论天线如何辐射开始的。
从麦克斯韦方程组，我们得出了电磁波。
之后，进行冗长的讨论，其中包含了很多数学，我们在讨论这些波如何在导体上激发电流。
这个情节的下半部分，就是电流的辐射和产生的电磁波。
你可能已经研究过这个问题，或如果你想增进你的阅历，参考在电磁学方面的书籍。
研究电磁学就有了一些数学方面的见识来描述天线的辐射，并提供严谨，以防止错误。
我们跳过讨论这些方程，直接转到实际的问题。
这是很重要的认识到，天线在电流中产生辐射。
设计构成的控制电流产生预期的辐射分布，其所谓的方向图。
在许多情况下，问题是如何防止电流中的辐射，如在集成电路。
每当一电流变为在距离上从其返回电流中分隔，它发热着。
简单地说，我们的设计就是为了保持两个电流靠近在一起，以减少辐射。
一些讨论会忽略电流的分布，而作为代替则会考虑得出的数量，如在各个领域的光圈或磁流在一个缝隙或靠近边缘的一微带斑纹。
你会发现我们使用任何的概念来提供深入的或简化的数学。
天线1转换电路领域，必将成为传播的电磁波，并通过互惠，从通过电磁波中收集动力。
麦克斯韦方程组预测，任何时间变电气或磁场产生相反的领域和形成一电磁波。
波有其两个领域的面向正交，而且它在正常的方向上传播给由垂直的电场和磁场所定的飞机。
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Sensing Human Activity:GPS Tracking感应人类活动:GPS跟踪Stefan van der Spek1,*,Jeroen van Schaick1,Peter de Bois1,2and Remco de Haan1Abstract:The enhancement of GPS technology enables the use of GPS devices not only as navigation and orientation tools,but also as instruments used to capture travelled routes:assensors that measure activity on a city scale or the regional scale.TU Delft developed aprocess and database architecture for collecting data on pedestrian movement in threeEuropean city centres,Norwich,Rouen and Koblenz,and in another experiment forcollecting activity data of13families in Almere(The Netherlands)for one week.Thequestion posed in this paper is:what is the value of GPS as‘sensor technology’measuringactivities of people?The conclusion is that GPS offers a widely useable instrument tocollect invaluable spatial-temporal data on different scales and in different settings addingnew layers of knowledge to urban studies,but the use of GPS-technology and deploymentof GPS-devices still offers significant challenges for future research.摘要：增强GPS技术支持使用GPS设备不仅作为导航和定位工具,但也为仪器用来捕捉旅行路线:作为传感器,测量活动在一个城市或区域范围内规模。
代尔夫特开发过程和涂数据库架构对行人运动收集数据在三个欧洲城市中心、诺维奇、鲁昂、科布伦茨,和在另一个实验中收集活动数据的13个家庭在Almere(荷兰)一个星期。
本文提出的问题是:什么是GPS的价值是“传感器技术的测量活动的人吗?结论是,GPS提供了一个广泛的可用的工具来收集宝贵的时空数据在不同尺度和不同的设置添加新层的知识城市研究,但使用GPS技术和部署的GPS设备仍为未来的研究提供了重要的挑战。
Keywords:GPS;Tracking;People;Behaviour;Mapping;Movement.关键字：GPS；跟踪；人群：行为；制图；运动1.Introduction1.引言1.1.The Global Navigation Satellite System1.1全球导航卫星系统The availability of so-called geopositioning devices such as GPS(Global Positioning System) devices has grown enormously in the last decade and is still increasing.More and more people own a navigation system such as a TomTom,a GPS for orientation for outdoor uses,biking and geo-cachingor a mobile phone or other handheld communication device with built-in GPS.These devices are mainly used for orientation(determining where you are),navigation(determining where to go)and communication(exchanging information with others or accessing information services).But the devices can also be used for tracking,i.e.saving a travelled route into a track log.This ability makesthe technology useful to collect spatial-temporal data and thus as‘sensors’for observing and measuring activities of people[1].所谓的可用性geopositioning设备如GPS(全球定位系统)设备有了巨大的增长在过去的十年,仍在增长。
越来越多的人拥有自己的导航系统如TomTom GPS定向用于户外,骑自行车和geo 缓存或手机或其他手持通信设备内置GPS。
这些设备主要用于定向(确定你在哪里),导航(确定去哪里)和沟通(与他人交换信息或访问信息服务)。
但设备还可以用于跟踪,即节约了旅行路线进入跟踪日志。
这种能力使得有用的技术来收集数据,因此时空“传感器”观察和测量活动的人[1]。
GPS is a Global Navigation Satellite System(GNSS).GNSS is a system for location or position determination–so called geopositioning[2].Using a special receiver,a geoposition in space and time can be calculated based on the reception of satellite signals.The United States’Global Positioning System(GPS)was the first available system using satellite Position Determination Technology(PDT) [2].Other GNSSs are under development in Europe(Galileo)and Russia(Glonass).GPS是一种全球导航卫星系统(GNSS)。
GNSS系统对位置或位置测定——所谓的geopositioning[2]。
使用一个特殊的接收器,一个geoposition在空间和时间的基础上可以计算卫星信号的接收。
美国的全球定位系统(GPS)是第一个可用的系统使用卫星定位技术(PDT)[2]。
其他GNSSs正在发展在欧洲(伽利略)和俄罗斯(格洛纳斯)。
GNSS is an essential Positioning Determination Technology for many fields of study.Although in recent years the system has undergone a significant‘modernisation’to improve its quality[2],the capability for geopositioning in the built-up(urban)environment is still one of its major weaknesses.In particular the availability of accurate indoor signals and with low speeds is limited.The futureavailability of Galileo is expected to increase the performance of GPS significantly[3].New technology such as high-sensitive GPS receivers will improve the accessibility to GPS signals.GNSS技术是一个重要的定位确定为许多研究领域。
虽然近年来系统进行了重要的“现代化”,以改善其质量[2],geopositioning的能力在组合(城市)环境仍然是它的一个主要弱点。
特别是室内信号的可用性和较低的准确速度是有限的。
未来的可获性伽利略预计将增加GPS的性能显著[3]。
新技术如高灵敏度GPS接收机将提高可访问性对GPS信号。
1.2.Seeing the Global Navigation Satellite System as Sensor Technology1.2.看到全球导航卫星系统作为传感器技术The most general definition of a sensor is‘a device which detects or measures a physical property’(Compact Oxford English Dictionary).A more specific definition of a sensor is‘a device that respondsto a physical stimulus(as heat,light,sound,pressure,magnetism,or a particular motion)and transmitsa resulting impulse(as for measurement or operating a control)’(Merrian Webster).Seeing GPS as a sensor requires use of the latter definition.Rather than a physical property it measures the location and motion of a GPS device and the person or object that carries it.The output is in the form of a track logwith3-dimensional spatial location coordinates and a time stamp.In an effort to characterize different types of sensors,Michahelles and Schiele[4]distinguish six sensing dimensions of which location, activity and interaction apply to GPS.Their analysis of sensor applications shows the appropriatenessof placing GPS devices on both humans and objects.The experiments in this paper are limited to GPS devices carried by humans and the‘location’and‘activity’dimensions of sensing.最通用的定义,一个传感器是一种检测装置,或衡量一个物理性质”(紧凑的牛津英语词典)。