大学计算机专业英语（第二版）-孙建忠-大学教学资料课件PPT
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大学计算机专业英语（第二版）-孙建忠-大学教学资料课件PPT,大学计算机,专业,英语,第二,孙建忠,大学,教学,资料,课件,ppt
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Computer English,Chapter 13 Virtual Reality,Key points: useful terms and definitions of Virtual Reality Difficult points: applications and features of VRML,Requirements:,Concept of virtual reality,2. Applications of VRML,3. Describe the features of VRML,4. 了解广告文体的特点,New Words & Expressions: Virtual reality 虚拟现实 jerky 颠簸的，急动的，此处指图像抖动 abuse 吸毒，滥用 prevent from 阻止，妨碍 in front of 在前面 relay vt. vi. 中继，转播 haptic a. 触觉的 stylus n. 指示笔，触针 dystrophy n. 营养失调 teleconference n.（远程）电信会议,13.1 Virtual Reality,Abbreviations: LCD (Liquid-Crystal Display) 液晶显示 HMD (Head-Mounted Display) 头部安装的显示器,13.1 Virtual Reality,Virtual reality is a system that enables one or more users to move and react in a computer-simulated environment. Various types of devices allow users to sense and manipulate virtual objects much as they would real objects1. This natural style of interaction gives participants the feeling of being immersed in the simulated world. Virtual worlds are created by mathematical models and computer programs. 虚拟现实是一个能让一个或多个用户在计算机模拟环境下移动和做出反应的系统。各种设备让用户去感觉和操作虚拟物体，就像他们是真实物体一样。这种自然的交互风格让参与者感到融入到模拟世界。虚拟世界是由数学模型和计算机程序创造的。,13.1 Virtual Reality,Virtual reality simulations differ from other computer simulations in that they require special interface devices that transmit the sights, sounds, and sensations of the simulated world to the user2. These devices also record and send the speech and movements of the participants to the simulation program. 虚拟现实模拟不同于其他要求特殊界面设备的计算机模拟，这些设备向用户传送模拟世界的视觉、声音和感觉。这些设备还向模拟程序记录和发送语音和参与者的运动。,13.1 Virtual Reality,To see in the virtual world, the user wears a head-mounted display (HMD) with screens directed at each eye. The HMD also contains a position tracker to monitor the location of the users head and the direction in which the user is looking. Using this information, a computer recalculates images of the virtual world a slightly different view for each eye to match the direction in which the user is looking, and displays these images on the (HMD) . 要观看虚拟世界，用户戴上一个头部安装的显示器(HMD)，HMD上有在每只眼睛前表演的屏幕。HMD还包括一个监视用户头部位置和观看方向的跟踪器。用这个信息，计算机重新计算每只眼睛稍微视觉差异的虚拟世界图像，使它与用户的观察方向一致，同时在HMD上显示这些图像。,13.1 Virtual Reality,The computer must generate these new views at least ten times a second in order to prevent the users view from appearing halting and jerky and from lagging behind the users movements. Virtual-world scenes must be kept relatively simple so that the computer can update the visual imagery quickly enough. Because of these simplifications and other shortcomings of current visual displays and computer graphics, VR participants can easily distinguish a simulation from physical reality. 为了防止用户视觉出现停止和抖动以及滞后于用户的运动，计算机必须以每秒至少十次的速度生成这些新图像。虚拟世界的场景必须保持相对简单，这样计算机就能够快的更新视觉图像。由于这些简单化及当前视觉现实和计算机图形的缺点，虚拟现实参与者能很容易从物理现实中区分出模拟事物。,13.1 Virtual Reality,Users hear sounds in the virtual world through earphones in the HMD, the information reported by the position tracker on the HMD can also be used to update audio signals. When a sound source in virtual space is not directly in front of or behind the user, the computer transmits sounds to arrive at one ear a little earlier or later than at the other and to be a little louder or softer and slightly different in pitch. However, as with visual imagery, there are currently scientific and engineering challenges that must be overcome in order to simulate accurately all the sounds heard in the physical world. 在虚拟世界中，用户通过HMD中的耳机听到声音，HMD中的位置跟踪器报告的信息也能用来更换音频信号。当虚拟空间的声源不直接在用户的前方或后方，计算机传达到某只耳朵的声音比到另一只稍微早些或晚些。然而，正如视觉图像，为了准确模拟物理世界听到的声音，当前科学和工程面临必须克服的挑战。,13.1 Virtual Reality,The haptic interface, which relays, the sense of touch and other physical sensations in the virtual world, is the least developed and perhaps the most challenging to create. Currently, with the use of a glove and position tracker, the computer locates the users hand and measures finger movements. The user can reach into the virtual world and handle objects but cannot actually feel them. 中继虚拟世界中触觉和其他物理感觉的触觉界面最不发达、而且大概要引起最大挑战。当前，由于使用了手套和位置跟踪器，计算机使用户的手定位，而且测量手指的运动。用户能达到虚拟世界而且触摸物体，但不能实际感觉到他们。,13.1 Virtual Reality,It is particularly difficult to generate the sensations that are felt when a person taps a hard surface, picks up an object, or runs a finger across a textured surface. To simulate these sensations, a set of computer-controlled motors faster and more accurate than any presently available would have to generate force feedback by physically pushing against the user. Another problem is determining how a user would wear these motors and the wiring needed to control them. 当某人轻敲一个硬的表面，捡起一个物体、或手指拂过有织纹的表面时，特殊难产生出感觉到的感觉。要模拟这些感觉，一套比目前能得到的任何电机都快和精确的计算机控制的电机将必须由多用户的实际推力产生反馈力。另一个问题是决定用户如何穿戴这些电机和用于控制他们的电线。,13.1 Virtual Reality,Touch sensations would also have to be synchronized with the sights and sounds users experienced in their HMDs. A current solution to the haptic challenge is the use of desktop devices that can apply small forces, through a mechanical linkage, to a stylus held in the users hand. Users can feel when the point of the stylus encounters a virtual object, and they can drag the stylus across the surface to feel its texture and surface geometry. 触觉还必须与用户在他们HMD中经历的视觉和声音同步。对触觉挑战的当前解决办法是使用可以施加小力的，通过一个机械连赶到用户手中握着的触针的台式设备。当触针的针尖碰到一个虚拟物体，用户能感觉到，而且他们能在表面上拖过触针来感觉它的织纹和表面几何形状。,13.1 Virtual Reality,In recent years, virtual-reality devices have improved dramatically as the result of various technological advances. Computers now are more powerful, have a higher memory capacity, are smaller, and cost less than in past. These developments, along with the advent of small liquid-crystal displays (LCDs) that can be used in HMDs, have made it possible for scientists to develop virtual-reality simulation. 最近几年，由于各种技术进步的结果，虚拟现实设备已显著改进。现在计算机功能更强大，存储容量更高，比过去更小，价格更低。伴随着可以用在HMD的小型液晶显示器的到来，这些发展已经使科学家开发虚拟现实模拟成为可能。,13.1 Virtual Reality,Virtual-reality is currently used to explore and manipulate experimental data in ways that were not possible before. Therapists use VR to treat sufferers of child abuse and people who are afraid of heights. Muscular dystrophy patients can learn to use a wheelchair through virtual reality. 虚拟现实当前用于探索和操纵实验数据，以前这种方式是不可能的。精神治疗家用VR去治疗儿童虐待的受害者和恐高症患者。肌肉萎缩患者可以通过虚拟现实学习使用轮椅。,13.1 Virtual Reality,In the future, surgeons may use VR to plan and practice an operation on a virtual patient rather than a real person. Architects could take clients on a virtual tour of a new house before it was built. VR could be used to train the operators of aircraft and other complicated machinery. Network VR simulations could enable people in many different locations to participate together in teleconferences, virtual surgical operations, or simulated military training exercises. 将来，外科医生可以用VR在虚拟病人身上计划和实习手术，而不是在真人身上。在房子建设前，建筑师可以带领客户在新房中作虚拟旅行。VR可以用来训练战斗机和其它复杂机械的操作者。网络VR模拟能让在许多不同地方的人一起参加电信会议、虚拟外科手术或模拟军事演习。,13.2 Real Work in Virtual Reality,In the future, your office may be less like a cubicle and more like the Holodeck on “Star Trek”. Computer scientists are already experimenting with the technology, called tele-immersion, that will allow us to peer into the offices of colleagues hundreds of miles away and make us feel as if we are sharing the same physical space. 将来你的办公室也许不像个小卧室而更像星际旅行的全息驾驶舱。计算机科学家已经用叫做远程参与的技术进行试验，这将我们窥见数百英里以外同事的办公室，使我们感到就像我们在分享同一物理空间。,13.2 Real Work in Virtual Reality,Computer scientists at several universities working on a project called the National Tele-Immersion Initiative have demonstrated a prototype system that enables a scientist working at his desk in Chapel Hill to see his distant colleagues on two screens mounted at right angles to his desk. It gives him the illusion of looking through windows into offices on the other side. And unlike videoconferencing, tele-immersion provides life-size 3-D images. 致力于国家远程参与主动性项目的几所大学计算机科学家已展示了一个原始系统，让在他的Chapel Hall办公室桌上工作的科学家能在他桌上直角安装的两个屏幕上看到他的远方同事。这给他一个错觉就像是从窗户看到另一面的办公室。与视频会议不同，远程参与提供真实的立体图像。,13.2 Real Work in Virtual Reality,In the prototype system, each researcher is surrounded by a bank of digital cameras that monitor his movements from a variety of angles. The researchers also wear head-mounted tracking gear and polarized glasses similar to those used to view 3-D movies. When a researcher moves his head, his view of his co-workers shifts accordingly. If he leans forward, for example, his colleagues appear closer, even though they are hundreds of miles away. 在原始系统中，每位研究人员被一群从不同角度监视他的摄像机所包围。研究人员还带着头部安装的跟踪装置和类似那些用于观看立体电影的偏振眼睛。当研究人员移动他的脑袋时，他的同事的图像也相应变动。例如，如果它向前倾，他的同事就靠近，虽然他们相距数百英里。,13.2 Real Work in Virtual Reality,To make the system work, powerful computers must convert digital images of each participant into data that is transmitted via the Internet, then reconstructed into images projected on the screens. So far, the movement is jerky because todays computers cannot transmit data fast enough. 要使系统工作，强大的计算机必须把每个参与者图像转换通过因特网传输的数据，然后重新还原或投射在屏幕上的图像。到目前为止，因为现在的计算机不能足够快地传送数据，运动还是抖动的。,13.2 Real Work in Virtual Reality,The scientists hope that tele-immersion will open up a host of other applications: For example, patients in rural areas could “visit” medical specialists in faraway cities. 科学家们希望远程参与将通向许多其它的应用，例如，农村的患者可以“瞧”远在城市的医学专家。,New Words & Expressions: interactive 交互的 intranet n.企业内部互联网 integrate 使成整体，结合 visualization n.可视化 presentation n.演示 virtual adj.虚拟的 criteria 准则 authorability n. 创作性 compose 组成，写作，排字 re-usability n. 可重用性 extensibility 可扩展性 explicitly 明白地，明确地 platform 平台 arbitrarily 武断地，任意地 static 静态的 animated 动画的，活生生的 dynamic 动态的 hyperlink 超级联接 author v. 制作 available 可利用的 registration 注册，登记 community 团体，公用 interoperable 能共同使用的 extension n. 延长，范围 scope 范围 specification 规范，说明书,13.3 About VRML,New Words & Expressions: conceptually 概念地 aural 听觉的 modify 更改，修改 mechanisms 机制 primary 原始的 composition 合成法，排版 encapsulation 封装 semantic 语义 resolution 分辨率 latitude 纬度，范围，地区 interpretation 解释，阐明 mouse 鼠标 implicitly 含蓄地，暗中地 coordinate 坐标 recursively 递归地，回归地 sphere 球体 reference 提及，参考书目 enclose 放入，封闭，包装 hierarchical 分层的，层次的 spatial adj. 空间的 accumulation 积聚，积累 dissipate v. 使消失，失去 intractable 难处理的 compact 紧凑的，简洁的 syntax n. 语法,13.3 About VRML,13.3 About VRML,Abbreviations : VRML (The Virtual Reality Modeling Language) 虚拟现实建模语言 API (application programmer interface) 应用程序界面,The Virtual Reality Modeling Language (VRML) is a file format for describing interactive 3D objects and worlds. VRML is designed to be used on the Internet, intranets, and local client systems. VRML is also intended to be a universal interchange format for integrated 3D graphics and multimedia. VRML may be used in a variety of application areas such as engineering and scientific visualization, multimedia presentations, entertainment and educational titles, web pages, and shared virtual worlds. 虚拟现实建模语言(VRML)是一种描述交互式三维对象及客观世界的文件格式。VRML用于Internet、Intranet和局域客户系统。VRML也是组合三维图形和多媒体的通用转换格式。VRML的应用领域很广，包括工程、科学可视化、多媒体演示、娱乐教育、Web页面和共享虚拟世界等方面。,13.3 About VRML,13.3.1 Design Criteria VRML has been designed to fulfill the following requirements: Authorability Enable the development of computer programs capable of creating, editing, and maintaining VRML files, as well as automatic translation programs for converting other commonly used 3D file formats into VRML files. 13.2.1 设计标准 VRML需要满足如下要求： 创作性 使得应用程序能够建立、编辑、保存VRML文件，也是一个自动翻译程序，能够将通常使用的3D文件格式转换成VRML文件。,13.3 About VRML,Composability Provide the ability to use and combine dynamic 3D objects within a VRML world and thus allow re-usability. Extensibility Provide the ability to add new object types not explicitly defined in VRML. 重构性 能够在VRML环境中使用和组合动态3D对象，并允许重用。 扩展性 能够加入在VRML中没有明确定义的新的对象类型。,13.3 About VRML,Implementability Capable of implementation on a wide range of systems. Performance Emphasize scalable, interactive performance on a wide variety of computing platforms. Scalability Enable arbitrarily large dynamic 3D worlds. 适用性 能够在各种系统中使用。 性能 在各种不同的计算机平台上强调可扩展的、交互的性能。 可扩展性 适于任意大的动态三维世界。,13.3 About VRML,13.3.2 Characteristics of VRML VRML is capable of representing static and animated dynamic 3D and multimedia objects with hyperlinks to other media such as text, sounds, movies, and images 1. VRML browsers, as well as authoring tools for the creation of VRML files, are widely available for many different platforms. VRML的特性 VRML能表示静态及动态的三维和多媒体对象，并通过超链接连到诸如文本、声音、电影及图像等其它媒体。VRML浏览器，同制作VRML文件的制作工具一样，广泛应用于许多不同的平台上。,13.3 About VRML,VRML supports an extensibility model that allows new dynamic 3D objects to be defined and a registration process that allows application communities to develop interoperable extensions to the base standard. There are mappings between VRML objects and commonly used 3D application programmer interface (API) features. VRML支持扩展模式，即允许创建新的3维动态对象，并允许应用程序组开发在基础模式上加以扩展的可共同操作的文件。在VRML对象和通常使用的应用程序接口特性间有相应的映射。,13.3 About VRML,13.3.3 Scope The VRML specification defines a file format that integrates 3D graphics and multimedia. Conceptually, each VRML file is a 3D time-based space that contains graphic and aural objects that can be dynamically modified through a variety of mechanisms. VRML defines a primary set of objects and mechanisms that encourage composition, encapsulation, and extension. VRML能表示静态及动态的三维和多媒体对象，并通过超链接连到诸如文本、声音、电影及图像等其它媒体。VRML浏览器，同制作VRML文件的制作工具一样，广泛应用于许多不同的平台上。,13.3 About VRML,The semantics of VRML describe an abstract functional behavior of time-based, interactive 3D, multimedia worlds. VRML does not define physical devices or any other implementation-dependent concepts (e.g., screen resolution and input devices). VRML is intended for a wide variety of devices and applications, and provides wide latitude in interpretation and implementation of the functionality. For example, VRML does not assume the existence of a mouse or 2D display device. VRML的语义描述了一个抽象的时间依赖的、交互性3维的功能行为。VRML并不定义一个具体的设备或任何依赖它实现的概念（比如：屏幕分辨率和输入设备）。VRML适用于大量的设备和应用程序，并且提供了一个对功能加以解释和实现的广泛空间。比如：VRML并不认为有鼠标或2维显示设备的存在。,13.3 About VRML,13.3.4 Each VRML file: 1. implicitly establishes a world coordinate space for all objects defined in the file, as well as all objects recursively included by the file; 2. explicitly defines and composes a set of 3D and multimedia objects; 3. can specify hyperlinks to other files and applications; 4. can define object behaviors. 1. 为文件中的所有对象建立了一个世界坐标系，也包括在文件中递归包含的所有对象。 2. 明确定义并构成一个3D和多媒体对象的集合。 3. 可定义超链接与其它文件和应用程序相连。 4. 可定义对象的行为。,13.3 About VRML,An important characteristic of VRML files is the ability to compose files together through inclusion and to relate files together through hyperlinking. For example, consider the file earth.wrl which specifies a world that contains a sphere representing the earth. This file may also contain references to a variety of other VRML files representing cities on the earth (e.g., file paris.wrl). The enclosing file, earth.wrl, defines the coordinate system that all the cities reside in. Each city file defines the world coordinate system that the city resides in but that becomes a local coordinate system when contained by the earth file. VRML文件的一个重要特性是能够通过包含和超链接将文件组合在一起。比如：文件earth.wrl, 定义了一个表示地球的球体， 它也可以包含指向表示地球上其它城市的文件的索引（如：文件 paris.wrl）。外封文件：earth.wrl定义了所有城市所处的坐标系。每一个城市文件定义了城市所在的世界坐标系系统，但是当包含在文件earth.wrl中时，就变成了局部坐标系统。,13.3 About VRML,Hierarchical file inclusion enables the creation of arbitrarily large, dynamic worlds. Therefore, VRML ensures that each file is completely described by the objects and files contained within it and that the effects of each file are strictly scoped by the file and the spatial limits of the objects defined in the file. Otherwise, the accumulation of files into larger worlds would produce unscalable results (as each added world produces global effects on all other worlds). 文件的层次关系允许创建任意大的、动态的世界。因此，VRML确保了每个文件由包含在其中的对象和文件完全描述，并且每个文件的效果由文件和文件中定义的对象的空间范围严格限定。否则的话，由很多文件定义一个大的世界坐标系将是不可扩展的（因为每一个加入的坐标会对其它坐标产生一个全局的影响）。,13.3 About VRML,For example, light sources have the potential of global effect since light energy theoretically does not dissipate to zero. And, if the earth file contains 100 city files each containing 100 lights each affecting all objects in the world, the lighting calculations would quickly become intractable. Therefore, in order to prevent global effects, light source objects are scoped by either a maximum radius or by location within the file. 比如，因为光能在理论上不会消失为0，光源对整体效果有潜在的影响。另外，如果地球文件包含100个城市文件，每个城市文件包含100个光源，会影响到整体坐标系的每个对象。光源的叠加将难于快速解决。因此，为了避免影响全局效果，光源对象或者由最大半径或者由文件内的一个区域限定。,13.3 About VRML,Another essential characteristic of VRML is that it is intended to be used in a distributed environment such as the World Wide Web. There are various objects and mechanisms built into the language that support multiple distributed files, including: 5. in-lining of other VRML files; 6. hyperlinking to other files; 7. using established Internet standards for other file formats; 8. defining a compact syntax VRML的另一基本特性是适用于分布式环境，如环球网。在语言内有不同的对象和固定机制支持多个分布式文件，包括： 5. 与其它VRML文件的链接； 6. 与其它类型文件的超链接； 7. 对其它格式文件使用确定的Internet标准； 8. 定义一个简洁的语法。,13.3 About VRML,一、个人简历 个人简历（resume/curriculum vitae）是升学、求职过程中的重要文件。英文个人简历的格式比较固定，一般应包括个人信息、联系地址、求职愿望、学历、工作经历、证明人等部分,也可以根据具体情况，适当增加有关条目。 内容的安排要求清晰易读、层次分明，学历和工作经历一般可从最近开始，逐渐向后追述。从语言方面来看，个人简历多以名词词组为主，也可以使用动词词组，但是要求结构整齐对称。 以下是某位学生的个人简历，他申请的工作职位是某计算机公司的售后服务技术员。一般来说，他还需另外撰写一份求职信，介绍一下本人的基本情况、特长及对该公司业务的熟悉程度，同时重申个人的工作愿望，并提出面试请求。,求职英语简介,一、个人简历 Resume Personal details Name: Li Jian Age: 20 Date of Birth: May 21,1981 Marital Status: single Address: 36 Yanshan Street, Jinan, Shandong 250014, P. R. China Tel: 0531-8937777 E-mail: lijian Position applied for After-sale Service Technician,求职英语简介,一、个人简历 Education： September 1995 to present Shandong Institute of Electronic Technology, Major in Applied Computing with special interest in networking & website implementation. Courses taken: C Programming, Software Engineering, Visual Foxpro, Microsfot Office, Data Structures in C, English for Computing, Computer Networks, Internet Application, etc. September 1992 to July 1995 Jinan No.14 Middle School, Jinan, Shandong. Monitor of class, outstanding in math & physics.,求职英语简介,一、个人简历 Work experience： Summer 1998 Company
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