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1外文文献翻译原文及译文汇总

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外文文献及翻译

外文文献及翻译

外文文献原稿和译文原稿DATABASEA database may be defined as a collection interrelated data store together with as little redundancy as possible to serve one or more applications in an optimal fashion .the data are stored so that they are independent of programs which use the data .A common and controlled approach is used in adding new data and in modifying and retrieving existing data within the data base .One system is said to contain a collection of database if they are entirely separate in structure .A database may be designed for batch processing , real-time processing ,or in-line processing .A data base system involves application program, DBMS, and database.THE INTRODUCTION TO DATABASE MANAGEMENT SYSTEMSThe term database is often to describe a collection of related files that is organized into an integrated structure that provides different people varied access to the same data. In many cases this resource is located in different files in different departments throughout the organization, often known only to the individuals who work with their specific portion of the total information. In these cases, the potential value of the information goes unrealized because a person in other departments who may need it does not know it or it cannot be accessed efficiently. In an attempt to organize their information resources and provide for timely and efficient access, many companies have implemented databases.A database is a collection of related data. By data, we mean known facts that can be recorded and that have implicit meaning. For example, the names, telephone numbers, and addresses of all the people you know. You may have recorded this data in an indexed address book, or you may have stored it on a diskette using a personalcomputer and software such as DBASE Ⅲor Lotus 1-2-3. This is a collection of related data with an implicit meaning and hence is a database.The above definition of database is quite general. For example, we may consider the collection of words that made up this page of text to be usually more restricted. A database has the following implicit properties:● A database is a logically coherent collection of data with some inherent meaning. A random assortment of data cannot be referred to as a database.● A database is designed, built, and populated with data for a specific purpose. It has an intended group of user and some preconceived applications in which these users are interested.● A database represents some aspect of the real world, sometimes called the miniworld. Changes to the miniworld are reflected in the database.In other words, a database has some source from which data are derived, some degree of interaction with events in the real world, and an audience that is actively interested in the contents of the database.A database management system (DBMS) is composed of three major parts: (1) a storage subsystem that stores and retrieves data in files; (2)a modeling and manipulation subsystem that provides the means with which to organize the data and to add, delete, maintain, and update the data; and (3) an interface between the DBMS and its users. Several major trends are emerging that enhance the value and usefulness of database management systems.●Managers who require more up-to-date information to make effective decisions.●Customers who demand increasingly sophisticated information services and more current information about the status of their orders, invoices, and accounts.●Users who find that they can develop custom applications with database systems in a fraction of the time it takes to use traditional programming languages.●Organizations that discover information has a strategic value; they utilize their database systems to gain an edge over their competitors.A DBMS can organize, process, and present selected data elements from the database. This capability enables decision makers to search, probe, and query database contents in order to extract answers to nonrecurring and unplanned questions that aren’t available in regular reports. These questions might initially be vague and/or p oorly defined, but people can “browse” through the database until they have the needed information. In short, the DBMS will “mange” the stored data items and assemble the needed items from the common database in response to the queries of those who aren’t programmers. In a file-oriented system, user needing special information may communicate their needs to a programmer, who, when time permits, will write one or more programs to extract the data and prepare the information. The availability of a DBMS, however, offers users a much faster alternative communications path.DATABASE QUERYIf the DBMS provides a way to interactively enter and update the database ,as well as interrogate it ,this capability allows for managing personal database. However, it does not automatically leave an audit trail of actions and does not provide the kinds of controls necessary in a multi-user organization .There controls are only available when a set of application programs is customized for each data entry and updating function.Software for personal computers that perform some of the DBMS functions has been very popular .Individuals for personal information storage and processing intended personal computers for us .Small enterprises, professionals like doctors, architects, engineers, lawyers and so on have also used these machines extensively. By the nature of intended usage ,database system on there machines are except from several of the requirements of full-fledged database systems. Since data sharing is not intended, concurrent operations even less so ,the software can be less complex .Security and integrity maintenance are de-emphasized or absent .as data volumes will be small, performance efficiency is also less important .In fact, the only aspect of a database system that is important is data independence. Data independence ,as stated earlier ,means that application programs and user queries need not recognize physical organization of data on secondary storage. The importance of this aspect , particularly for the personal computer user ,is that this greatly simplifies database usage . The user can store ,access and manipulate data at ahigh level (close to the application)and be totally shielded from the low level (close to the machine )details of data organization.DBMS STRUCTURING TECHNIQUESSpatial data management has been an active area of research in the database field for two decades ,with much of the research being focused on developing data structures for storing and indexing spatial data .however, no commercial database system provides facilities for directly de fining and storing spatial data ,and formulating queries based on research conditions on spatial data.There are two components to data management: history data management and version management .Both have been the subjects of research for over a decade. The troublesome aspect of temporal data management is that the boundary between applications and database systems has not been clearly drawn. Specifically, it is not clear how much of the typical semantics and facilities of temporal data management can and should be directly incorporated in a database system, and how much should be left to applications and users. In this section, we will provide a list of short-term research issues that should be examined to shed light on this fundamental question.The focus of research into history data management has been on defining the semantics of time and time interval, and issues related to understanding the semantics of queries and updates against history data stored in an attribute of a record. Typically, in the context of relational databases ,a temporal attribute is defined to hold a sequence of history data for the attribute. A history data consists of a data item and a time interval for which the data item is valid. A query may then be issued to retrieve history data for a specified time interval for the temporal attribute. The mechanism for supporting temporal attributes is to that for supporting set-valued attributes in a database system, such as UniSQL.In the absence of a support for temporal attributes, application developers who need to model and history data have simply simulated temporal attributes by creating attribute for the time interval ,along with the “temporal” attribute. This of course may result in duplication of records in a table, and more complicated search predicates in queries. The one necessary topic of research in history data management is to quantitatively establish the performance (and even productivity) differences betweenusing a database system that directly supports attributes and using a conventional database system that does not support either the set-valued attributes or temporal attributes.Data security, integrity, and independenceData security prevents unauthorized users from viewing or updating the database. Using passwords, users are allowed access to the entire database of the database, called subschemas. For example, an employee database can contain all the data about an individual employee, but one group of users may be authorized to view only payroll data, while others are allowed access to only work history and medical data.Data integrity refers to the accuracy, correctness, or validity of the data in the database. In a database system, data integrity means safeguarding the data against invalid alteration or destruction. In large on-line database system, data integrity becomes a more severe problem and two additional complications arise. The first has to do with many users accessing the database concurrently. For example, if thousands of travel agents book the same seat on the same flight, the first agent’s booking will be lost. In such cases the technique of locking the record or field provides the means for preventing one user from accessing a record while another user is updating the same record.The second complication relates to hardware, software or human error during the course of processing and involves database transaction which is a group of database modifications treated as a single unit. For example, an agent booking an airline reservation involves several database updates (i.e., adding the passenger’s name and address and updating the seats-available field), which comprise a single transaction. The database transaction is not considered to be completed until all updates have been completed; otherwise, none of the updates will be allowed to take place.An important point about database systems is that the database should exist independently of any of the specific applications. Traditional data processing applications are data dependent.When a DMBS is used, the detailed knowledge of the physical organization of the data does not have to be built into every application program. The application program asks the DBMS for data by field name, for example, a coded representationof “give me customer name and balance due” would be sent to the DBMS. Without a DBMS the programmer must reserve space for the full structure of the record in the program. Any change in data structure requires changes in all the applications programs.Data Base Management System (DBMS)The system software package that handles the difficult tasks associated with creating ,accessing and maintaining data base records is called a data base management system (DBMS). A DBMS will usually be handing multiple data calls concurrently.It must organize its system buffers so that different data operations can be in process together .It provides a data definition language to specify the conceptual schema and most likely ,some of the details regarding the implementation of the conceptual schema by the physical schema.The data definition language is a high-level language, enabling one to describe the conceptual schema in terms of a “data model “.At the present time ,there are four underling structures for database management systems. They are :List structures.Relational structures.Hierarchical (tree) structures.Network structures.Management Information System(MIS)An MIS can be defined as a network of computer-based data processing procedures developed in an organization and integrated as necessary with manual and other procedures for the purpose of providing timely and effective information to support decision making and other necessary management functions.One of the most difficult tasks of the MIS designer is to develop the information flow needed to support decision making .Generally speaking ,much of the information needed by managers who occupy different levels and who have different levels and have different responsibilities is obtained from a collection of exiting information system (or subsystems)Structure Query Language (SQL)SQL is a data base processing language endorsed by the American NationalStandards Institute. It is rapidly becoming the standard query language for accessing data on relational databases .With its simple ,powerful syntax ,SQL represents a great progress in database access for all levels of management and computing professionals.SQL falls into two forms : interactive SQL and embedded SQL. Embedded SQL usage is near to traditional programming in third generation languages .It is the interactive use of SQL that makes it most applicable for the rapid answering of ad hoc queries .With an interactive SQL query you just type in a few lines of SQL and you get the database response immediately on the screen.译文数据库数据库可以被定义为一个相互联系的数据库存储的集合。

外文文献原稿和译文

外文文献原稿和译文

外文文献原稿和译文原稿MechanicalandRegenerativeBrakingIntegrationforaHybridElectricVehicleAbstract,namelyanelectricmotorandinternalcombustionengine,whichallowtheelimina tionofidling,,theaddedcostofthehybridelectricsystemhashinderedthesalesofth esevehicles.JapanNorth America automotive companieshavedevelopedandreleasedforsaletheirownhybridelectric unpredictablegasprices,thesalesofhybridelectricvehicleshaveincreaseddramat ically inrecentyears.2.1.1HybridConfigurationsForthepast100yearstheobjectiveofthehybridhasbeentoextendtherangeofelec tricvehiclesandtoovercometheproblemoflongrechargingtimes35.Therearethree ,par allelhybridsandseries/parallelhybrids.Eachconfigurationhasitsadvantagesanddisadvantageswhichwillbediscussedi nthefollowingsections.SeriesHybridsInserieshybridsthemechanicaloutputfromtheinternalcombustionengineisuse dto driveageneratorwhichproduceselectricalpowerthatcanbestoredinthebatteriesor highpowersystemssuchaslargetrucksorlocomotivesbutcanalsobeusedforlowerpowe rpassengervehicles18.2.1.2‘degreeofhybridization’toquantifytheelectrica lpowerpotentialofthesevehicles.ThedegreeofhybridizationrangesfromDOH=0foraconventionalvehicletoDOH=1f oranallelectricvehicle25.Asthedegreeofhybridizationincreases,asmallerICEcanbeusedandoperatedclosertoitsoptimumefficiencyforagreaterproportionoftheti me,.MicroHybrid MicrohybridshavethesmallestdegreeofhybridizationandusuallyconsistofanintegratedstartergeneratorISG2.1.31500 kg100 km/h0 km/h0 km/h50 km/h2.1.42.1.5译文混合动力电动汽车机械和再生制动的整合摘要为了减少对环境的污染和车辆的燃油消耗,混合动力电动汽车已经成为汽车工业的首选方法;混合动力电动汽车通过使用由电动马达和内燃发动机组成的混合动力系统来达到减少环境污染和燃油消耗的目的;混合动力系统消除了怠速,使发动机以一种更有效的方式运行,增加了再生制动的使用;但是,混合动力的成本的增加阻碍了这些车辆的销售;在这里提出一个更具成本效益的电液制动系统的设计;该系统使用电控机械结合的控制方式控制制动助力器产生的推动力,并有足够的时间反应;这个系统使驾驶员清楚地了解机械和再生制动力矩的混合,使再生制动力系统得到有效的控制;一个系统化的设计过程是其次,重点在于展示概念设计方案的可行性和使用虚拟和实物模型的初步设计功用;虚拟和实物模型的结合使用成为验证和开发系统的强大工具,本文将介绍和讨论在设计过程中模型所起到的作用;因为在设计过程中设计者可以获得相关的经验,提倡学生设计实物模型,以提高学生的学习经验;很明显,这正是本文所要提出的;现代混合动力电动汽车随着油价的上涨和环境保护意识的提高,消费者和政府迫使汽车行业开始生产省油和对环境污染小的汽车;一个有前景的方法就是现在实行的混合动力电动汽车;混合动力汽车指的是有两个或两个以上动力来源的车辆;混合动力汽车动力的来源可能有很多的不同,但是现在混合动力汽车最常见的布局是由内燃发动机和电动马达,能量储存系统共同输出动力,这样的车辆就叫混合动力电动汽车;汽车可以同时使用发动机和电动马达输出的动力,从而可以提高汽车的使用性能和效率,进而又可以提高燃油经济性,减少废气的排放,同时还能满足消费者对汽车性能的要求;1997年,丰田成普瑞斯为了第一款混合动力电动汽车,在日本进行了批量生产;本田公司花费了三年的时间进行混合动力电动车的生产,然后进军北美市场;丰田普瑞斯在北美发行几个月后,本田Insight紧随其后也在北美进行发行;混合动力电动车具有再生制动系统的独特优势;在制动过程,通常用于动力输出的电动马达,可以起到发电机的功用,把汽车的动能转化为蓄电池的电能,而不会转化为热能浪费掉;转换的电能可以储存到蓄电池中,然后可以作为电动马达驱动汽车使用的能量;考虑到蓄电池能量密度时,动能转换为电能这个过程就更加重要了;能量密度是指单位体积或质量下能量储存系统所储存的能量;为了说明这一点,我们可以做个对比,4.5公升的汽油通常可以维持一辆汽车行驶50千米;而要把相同的能量储存到蓄电池中,则需要一个质量约为270千克的铅酸蓄电池;这就说明了在汽车行驶过程中能够有效地储存再生制动系统产生的能量的重要性,从而可以保证在提高混合动力电能车性能的前提下,不至使能量储存系统所占体积过大;再生制动系统研究范围本文所提出的再生系统的研究范围是研究再生制动系统和机械制动系统之间相互作用的关系,目的是设计开发出一个低成本的再生制动系统,从而可以应用到未来经济型的混合动力电动汽车上;这个系统可以根据驾驶员的需要进而控制再生制动系统和机械制动系统产生的制动力矩的结合,还应该保证这个过程的平顺性和安全性;再生制动力矩是通过使用的异步电动机的矢量控制算法进行控制的;但是,独立地控制制动踏板产生的机械制动力矩,同时又要保持机械制动系在再生制动系统失效后起到备用作用,这是一个很大的难题;为了解决这个问题,需要研究一个通过减少制动主缸内制动液压来来控制机械制动系统产生的制动力矩的制动系统;混合电动汽车概述混合动力电动车已经成为了可以在短时间内减少汽车污染排放和提高燃油经济型的解决方法之一;在过去的10年几乎所有的主要汽车公司都已经向公众发行销售自己的混合动力电动汽车,混合动力电动汽车的普及和销售在这个世纪有了很明显的增长,随着不可预测的汽油价格的增长和对环境保护的关注,混合动力电动汽车的销售将在最近几年内急剧增长;2.1.1混合动力装置在过去100年来混合动力的研究目标是延长电动汽车的使用寿命,解决蓄电池的长期充电问题;在目前市场,现在主要有三种混合动力装置,这些混合动力装置为串联混合动力,并联混合动力,串并联混合动力;每一种动力装置都有其优点和缺点,这将在以后的章节进行讨论;串联混合动力串联混合动力汽车使用发动机输出的动力来驱动发电机产生电能,这些电能可以储存在蓄电池中,也可以用来驱动电动马达来驱动汽车;在串联混合动力汽车上,发动机和驱动轮之间没有直接的机械连接,串联混合动力往往在高功率系统中使用,如大型货车或火车,也可以应用到低功率的客运车辆上;发动机输出的机械能和蓄电池输出的电能可以通过电子控制器进行控制接合,然后这个电子控制器通过比较驾驶员所需的动力和汽车车速,电动马达输出的转矩,从而决定每个动力源驱动汽车行驶所要输出的能量;在制动过程中,这个电子控制装置可以使电能输出模式转换为再生模式,直接把再生制动系统产生的电能储存在蓄电池内;按照这种布置方式进行设计有很多的优点;发动机可以保持高效率的运行,使发动机产生的电能在蓄电池和驱动马达之间得到分配;发动机在其最高效率的工况下运行,排放可以大大降低,燃烧每体积的燃料可以产生更多的电能;因为串联动力装置结构简单且成本低,这种动力装置很容在汽车上落实;并联混合动力在并联混合动力汽车中,发动机输出的机械功传到变速箱中;发动机输出的机械功和电动马达输出的功在变速箱内进行机械式的接合,混合的机械功用于驱动汽车行驶;在这种混合动力装置结构中,发动机和驱动轮之间有直接的机械连接;在串联混合动力装置中,电子控制器通过比较驾驶员所需的动力和汽车车速,电动马达输出的转矩,从而决定每个动力源驱动汽车行驶所要输出的能量,以满足汽车行驶性能,获得最佳的效率;正如串联混合装置一样,并联混合动力也以相似的方法控制再生制动;并联混合动力装置通常应用到低功率的电动车中,这两种驱动力可以同时使用,提供更高的行驶性能;与串联混合动力系统相比,并联混合动力系统有很多优势;其中最重要的一项优势是效率高,因为在并联混合动力中,电能和机械能只需转换一次,而在串联混合动力中,电能和机械能需要两次转换;由于并联混合动力可以使发动机和电动马大产生的动力同时结合起来,在不损失汽车行驶性能的前提下,可以使用体积小的电动马达,同时也降低了油耗和排放;最后,并联混合动力汽车在行驶过程中只需使发动机运行,而不需要另一个发电机为蓄电池充电;串、并联混合动力串并联混合动力装置结合了串联和并联动力装置的特点;这种混合方式汽车通过使用动力分配装置来控制双动力源电动马达输出动力,发动机输出动力或者两者同时输出驱动汽车行驶;虽然这种装置形式可以获得串联混合动力装置和并联混合动力装置的优点,因为考虑到汽车实际行驶可能性,这种装置的控制算法会变得非常复杂; 2.1.2混合度现在道路上行驶的混合动力电动汽车大多是串联混合动力,并联混合动力,或者串并联混合动力,因此定义一个‘混合度’变量来评价混合动力电动汽车的电能潜能是非常有意义的;混合度变从传统车辆DOH=0到所有电动车DOH=1之间变化,随着混合度的增加,在汽车上可以使用一个比较小的发动机,同时发动机可以在最接近最佳效率的工况下运行很长的时间,这样就可以减少燃油的消耗和废气的排放;电动马达输出的功用P表emP表示;示,发动机输出的功用ice微混合动力微混合指的是最小混合度,通常是由一个连接到发动机曲轴的综合起动发电机组成;在加速和怠速过程中,综合起动发电机使发动机处于关闭状态,从而节约燃油;加速时,在燃油喷入汽缸之前,综合起动发电机使发动机的曲轴加速旋转;在加速过程中,综合起动发电机对发动机起动协助的作用,在制动过程中,综合起动发电机还可以作为发电机向蓄电池充电;和非混合动力汽车相比,微混合动力汽车的燃油经济性可以提高10%左右;轻混合动力轻混合动力和微混合动力结构相似,有一点不同的是其综合起动发电机是经过改进的,其输出的动力可以超过20KW;但是,轻混合动力的能量储存系统只能储存1KWh左右的能量;轻混合动力汽车只有一个很短的纯电动续航能力,但是可以在加速过程中给发动机提供很大的辅助作用;轻混合动力中的电子元件要比微混合动力中的电子元件复杂的多,且在汽车行驶过程中发挥着更大的作用;和非混合动力的汽车相比,轻混合动力汽车的燃油经济性可以提高20%-25%左右;全混合动力在全混合动力汽车上不再使用综合起动发电机,取代它的是一个独立的电动马达和交流发电机、起动机,这些装置也可以起到综合起动发电机的作用;电动马达可以独立驱动汽车行驶,尤其是在城市道路上走走停停的行驶;能量储存系统也得到了改进,这样就提高了汽车纯电动续航能力,减少了发动机的体积,从而提高燃油经济性和减少排放;与非混合动力汽车相比,全混合动力汽车的燃油消耗量可以减少40%-50%;插电式混合动力插电式混合动力汽车在结构上和全混合动力汽车相似,不同的是插电式混合动力汽车有一个比较大的能量储存系统,可以通过与外部电源连接进行充电;在蓄电池储存能量范围内,可以通过电动马达来驱动汽车行驶,但是当蓄电池的能量降到一定水平后,其运行形势就和全混合动力一样了;2.1.3再生制动原理混合动力电动汽车最重要的特点是可以回收大量的制动能量;在制动过程中,电动马达可以作为发电机来运行操作,将制动过程中的动能转换为电能储存到蓄电池中,这些电能就可以被汽车重复使用;但是,车辆的制动性能就将影响到汽车的安全性;在紧急制动状态下,汽车的制动距离要尽可能的短,还要保证制动时汽车有较好的方向稳定性;汽车具有较好的方向稳定性,就需要控制车轮的制动力分配;一般来说,制动时所需的制动力矩比电动马达产生的制动力矩大得多;因此,机械制动系统需要和电子再生制动系统同时存在,这就需要适当的设计以保证制动时的操作稳定性,不至于影响到汽车的安全性;制动时能量消耗由公式可得,一个质量为1500Kg的汽车以100km/h初速度制动到完全停止,需要消耗的动能;如果这些能量的25%可以通过再生制动系统进行回收,当忽略制动和加速过程中的空气阻力,机械摩擦和滚动阻力,假设电动马达的工作效率100%,利用公式可以估算出,这些能量可以使汽车从0km/h加速到50km/h.这就表明,当汽车行驶在城市道路上,汽车不停加速和制动,混合动力电动车的燃油经济性可以大大增加;需要注意的是,制动能量的回收量受到马达的型号和能量转换率的限制;2.1.4再生制动系统目前,通常使用的有两种再生制动方法;这些方法通常称为串联再生制动和并联制动,每种制动策略都有其优点和缺点,本文对此将进行具体讨论;并联再生制动在并联再生制动系统中,电动马达和机械制动系统同时工作,从而使汽车减速;因为机械制动系统不能独立的控制制动力,使制动时的能量转换为热能而不是电能,因此这不是最有效地再生制动方法;但是并联再生制动结构简单成本低,这就成为其一大优势;并联再生制动的机械制动系统只需要稍加修改,而且电动马达的控制算法也可以很容易在汽车上实现;这种制动方法还有一个额外的优势,当再生制动系统发生故障时,机械制动系统可以起到备用的作用;串联再生制动在串联再生制动中,电动马达只有在制动时才起作用;只有当电动马达和能量储存系统无法接受更多制动时所需的能量时,再生制动系统才起作用;串联再生制动需要独立的控制制动力矩,串联再生制动可以高效率的把动能转换为电能,这是其一项优势;但是它的不足之处在于,制动系统结构复杂,成本高;这种制动方式需要制动踏板模拟器,制动系统也需要重新设计,这都会增加其制造成本;因为制动系统需要装有传感器和信息处理器,这就会增加了结构的复杂度;2.1.5目前的再生制动系统目前大多数混合动力电动汽车的再生制动系统都是比较昂贵的电液制动系统;再生制动系统使用制动踏板模拟器来建立驾驶者的制动需求,这个制动踏板模拟器与液压制动电路独立分开;这样再将制动需求按照一定比例转换为再生制动和机械制动需求,然后将机械制动需求发送到由高压液压泵,蓄能器和比例控制阀的系统;比例控制阀根据制动需求,控制制动液以一定的预定值流到每个车轮的制动轮缸中;。

智能交通系统中英文对照外文翻译文献

智能交通系统中英文对照外文翻译文献

智能交通系统中英文对照外文翻译文献(文档含英文原文和中文翻译)原文:Traffic Assignment Forecast Model Research in ITS IntroductionThe intelligent transportation system (ITS) develops rapidly along with the city sustainable development, the digital city construction and the development of transportation. One of the main functions of the ITS is to improve transportation environment and alleviate the transportation jam, the most effective method to gain the aim is to forecast the traffic volume of the local network and the important nodes exactly with GIS function of path analysis and correlation mathematic methods, and this will lead a better planning of the traffic network. Traffic assignment forecast is an important phase of traffic volume forecast. It will assign the forecasted traffic to every way in the traffic sector. If the traffic volume of certain road is too big, which would bring on traffic jam, planners must consider the adoption of new roads or improving existing roads to alleviate the traffic congestion situation. This study attempts to present an improved traffic assignment forecast model, MPCC, based on analyzing the advantages and disadvantages of classic traffic assignment forecast models, and test the validity of the improved model in practice.1 Analysis of classic models1.1 Shortcut traffic assignmentShortcut traffic assignment is a static traffic assignment method. In this method, the traffic load impact in the vehicles’ travel is not considered, and the traffic impedance (travel time) is a constant. The traffic volume of every origination-destination couple will be assigned to the shortcut between the origination and destination, while the traffic volume of other roads in this sector is null. This assignment method has the advantage of simple calculation; however, uneven distribution of the traffic volume is its obvious shortcoming. Using this assignment method, the assignment traffic volume will be concentrated on the shortcut, which isobviously not realistic. However, shortcut traffic assignment is the basis of all theother traffic assignment methods.1.2 Multi-ways probability assignmentIn reality, travelers always want to choose the shortcut to the destination, whichis called the shortcut factor; however, as the complexity of the traffic network, thepath chosen may not necessarily be the shortcut, which is called the random factor.Although every traveler hopes to follow the shortcut, there are some whose choice isnot the shortcut in fact. The shorter the path is, the greater the probability of beingchosen is; the longer the path is, the smaller the probability of being chosen is.Therefore, the multi-ways probability assignment model is guided by the LOGIT model:∑---=n j ii i F F p 1)exp()exp(θθ (1)Where i p is the probability of the path section i; i F is the travel time of thepath section i; θ is the transport decision parameter, which is calculated by the followprinciple: firstly, calculate the i p with different θ (from 0 to 1), then find the θwhich makes i p the most proximate to the actual i p .The shortcut factor and the random factor is considered in multi-ways probabilityassignment, therefore, the assignment result is more reasonable, but the relationshipbetween traffic impedance and traffic load and road capacity is not considered in thismethod, which leads to the assignment result is imprecise in more crowded trafficnetwork. We attempt to improve the accuracy through integrating the several elements above in one model-MPCC.2 Multi-ways probability and capacity constraint model2.1 Rational path aggregateIn order to make the improved model more reasonable in the application, theconcept of rational path aggregate has been proposed. The rational path aggregate,which is the foundation of MPCC model, constrains the calculation scope. Rationalpath aggregate refers to the aggregate of paths between starts and ends of the trafficsector, defined by inner nodes ascertained by the following rules: the distancebetween the next inner node and the start can not be shorter than the distance betweenthe current one and the start; at the same time, the distance between the next innernode and the end can not be longer than the distance between the current one and theend. The multi-ways probability assignment model will be only used in the rationalpath aggregate to assign the forecast traffic volume, and this will greatly enhance theapplicability of this model.2.2 Model assumption1) Traffic impedance is not a constant. It is decided by the vehicle characteristicand the current traffic situation.2) The traffic impedance which travelers estimate is random and imprecise.3) Every traveler chooses the path from respective rational path aggregate.Based on the assumptions above, we can use the MPCC model to assign thetraffic volume in the sector of origination-destination couples.2.3 Calculation of path traffic impedanceActually, travelers have different understanding to path traffic impedance, butgenerally, the travel cost, which is mainly made up of forecast travel time, travellength and forecast travel outlay, is considered the traffic impedance. Eq. (2) displaysthis relationship. a a a a F L T C γβα++= (2)Where a C is the traffic impedance of the path section a; a T is the forecast traveltime of the path section a; a L is the travel length of the path section a; a F is theforecast travel outlay of the path section a; α, β, γ are the weight value of that threeelements which impact the traffic impedance. For a certain path section, there aredifferent α, β and γ value for different vehicles. We can get the weighted average of α,β and γ of each path section from the statistic percent of each type of vehicle in thepath section.2.4 Chosen probability in MPCCActually, travelers always want to follow the best path (broad sense shortcut), butbecause of the impact of random factor, travelers just can choose the path which is ofthe smallest traffic impedance they estimate by themselves. It is the key point ofMPCC. According to the random utility theory of economics, if traffic impedance is considered as the negativeutility, the chosen probability rs p of origination-destinationpoints couple (r, s) should follow LOGIT model:∑---=n j jrs rs bC bC p 1)exp()exp( (3) where rs p is the chosen probability of the pathsection (r, s);rs C is the traffic impedance of the path sect-ion (r, s); j C is the trafficimpedance of each path section in the forecast traffic sector; b reflects the travelers’cognition to the traffic impedance of paths in the traffic sector, which has reverseratio to its deviation. If b → ∞ , the deviation of understanding extent of trafficimpedance approaches to 0. In this case, all the travelers will follow the path whichis of the smallest traffic impedance, which equals to the assignment results withShortcut Traffic Assignment. Contrarily, if b → 0, travelers ’ understanding error approaches infinity. In this case, the paths travelers choose are scattered. There is anobjection that b is of dimension in Eq.(3). Because the deviation of b should beknown before, it is difficult to determine the value of b. Therefore, Eq.(3) is improvedas follows:∑---=n j OD j OD rsrs C bC C bC p 1)exp()exp(，∑-=n j j OD C n C 11（4） Where OD C is the average of the traffic impedance of all the as-signed paths; bwhich is of no dimension, just has relationship to the rational path aggregate, ratherthan the traffic impedance. According to actual observation, the range of b which is anexperience value is generally between 3.00 to 4.00. For the more crowded cityinternal roads, b is normally between 3.00 and 3.50.2.5 Flow of MPCCMPCC model combines the idea of multi-ways probability assignment anditerative capacity constraint traffic assignment.Firstly, we can get the geometric information of the road network and OD trafficvolume from related data. Then we determine the rational path aggregate with themethod which is explained in Section 2.1.Secondly, we can calculate the traffic impedance of each path section with Eq.(2),Fig.1 Flowchart of MPCC which is expatiated in Section 2.3.Thirdly, on the foundation of the traffic impedance of each path section, we cancalculate the respective forecast traffic volume of every path section with improvedLOGIT model (Eq.(4)) in Section 2.4, which is the key point of MPCC.Fourthly, through the calculation processabove, we can get the chosen probability andforecast traffic volume of each path section, but itis not the end. We must recalculate the trafficimpedance again in the new traffic volumesituation. As is shown in Fig.1, because of theconsideration of the relationship between trafficimpedance and traffic load, the traffic impedanceand forecast assignment traffic volume of everypath will be continually amended. Using therelationship model between average speed andtraffic volume, we can calculate the travel timeand the traffic impedance of certain path sect-ionunder different traffic volume situation. For theroads with different technical levels, therelationship models between average speeds totraffic volume are as follows: 1) Highway: 1082.049.179AN V = (5) 2) Level 1 Roads: 11433.084.155AN V = (6) 3) Level 2 Roads: 66.091.057.112AN V = (7) 4) Level 3 Roads: 3.132.01.99AN V = (8) 5) Level 4 Roads: 0988.05.70A N V =(9) Where V is the average speed of the path section; A N is the traffic volume of thepath section.At the end, we can repeat assigning traffic volume of path sections with themethod in previous step, which is the idea of iterative capacity constraint assignment,until the traffic volume of every path section is stable.译文智能交通交通量分配预测模型介绍随着城市的可持续化发展、数字化城市的建设以及交通运输业的发展，智能交通系统（ITS）的发展越来越快。

外文文献及译文

外文文献及译文

外文原文FIR Filter Design TechniquesAbstractThis report deals with some of the techniques used to design FIR filters. In the beginning, the windowing method and the frequency sampling methods are discussed in detail with their merits and demerits. Different optimization techniques involved in FIR filter design are also covered, including Rabiner‟s method for FIR filter design. These optimization techniques reduce the error caused by frequency sampling technique at the non-sampled frequency points. A brief discussion of some techniques used by filter design packages like Matlab are also included.IntroductionFIR filters are filters having a transfer function of a polynomial in z and is an all-zero filter in the sense that the zeroes in the z-plane determine the frequency response magnitude characteristic.The z transform of a N-point FIR filter is given by(1)FIR filters are particularly useful for applications where exact linear phase response is required. The FIR filter is generally implemented in a non-recursive way which guarantees a stable filter.FIR filter design essentially consists of two parts(i) approximation problem(ii) realization problemThe approximation stage takes the specification and gives a transfer function through four steps. They are as follows:(i) A desired or ideal response is chosen, usually in the frequency domain.(ii) An allowed class of filters is chosen (e.g.the length N for a FIR filters).(iii) A measure of the quality of approximation is chosen.(iv) A method or algorithm is selected to find the best filter transfer function.The realization part deals with choosing the structure to implement the transfer function which may be in the form of circuit diagram or in the form of a program.There are essentially three well-known methods for FIR filter design namely:(1) The window method(2) The frequency sampling technique(3) Optimal filter design methodsThe Window MethodIn this method, [Park87], [Rab75], [Proakis00] from the desired frequency response specification Hd(w), corresponding unit sample response hd(n) is determined using the following relation(2)(3)In general, unit sample response hd(n) obtained from the above relation is infinite in duration, so it must be truncated at some point say n= M-1 to yield an FIR filter of length M (i.e. 0 to M-1). This truncation of hd(n) to length M-1 is same as multiplying hd(n) by the rectangular window defined asw(n) = 1 0≦n≦M-1 (4)0 otherwiseThus the unit sample response of the FIR filter becomesh(n) = hd(n) w(n) (5) = hd(n) 0≦n≦M-1= 0 otherwiseNow, the multiplication of the window function w(n) with hd(n) is equivalent to convolution of Hd(w) with W(w), where W(w) is the frequency domain representation of the window function(6)Thus the convolution of Hd(w) with W(w) yields the frequency response of the truncated FIR filter(7)The frequency response can also be obtained using the following relation(8)But direct truncation of hd(n) to M terms to obtain h(n) leads to the Gibbs phenomenon effect which manifests itself as a fixed percentage overshoot and ripple before and after an approximated discontinuity in the frequency response due to the non-uniform convergence of the fourier series at a discontinuity.Thus the frequency response obtained by using (8) contains ripples in the frequency domain. In order to reduce the ripples, instead of multiplying hd(n) with a rectangular window w(n), hd(n) is multiplied with a window function that contains a taper and decays toward zero gradually, instead of abruptly as it occurs in a rectangular window. As multiplication of sequences hd(n) and w(n) in time domain is equivalent to convolution of Hd(w) and W(w) in the frequency domain, it has the effect of smoothing Hd(w).The several effects of windowing the Fourier coefficients of the filter on the result of the frequency response of the filter are as follows:(i) A major effect is that discontinuities in H(w) become transition bands between values on either side of the discontinuity.(ii) The width of the transition bands depends on the width of the main lobe of the frequency response of the window function, w(n) i.e. W(w).(iii) Since the filter frequency response is obtained via a convolution relation , it is clear that the resulting filters are never optimal in any sense.(iv) As M (the length of the window function) increases, the mainlobe width of W(w) is reduced which reduces the width of the transition band, but this also introduces more ripple in the frequency response.(v) The window function eliminates the ringing effects at the bandedge and does result in lower sidelobes at the expense of an increase in the width of the transition band of the filter.Some of the windows [Park87] commonly used are as follows:1. Bartlett triangular window:W(n)=2(n+1)/N+1 n=0,1,2…….,(N-1)/2 (9) =2-2(n+1)/N+1 n=(N-1)/2,……,N-1= 0 otherwise2 Generalized cosine windows(Rectangular, Hanning, Hamming and Blackman)W(n)=a-bcos(2p(n+1)/(N+1))+ccos(4p(n+1)/(N+1)) n=0,1….N-1 (10) = 0 otherwise3.Kaiser window with parameter β:(11)The general cosine window has four special forms that are commonly used. These are determined by the parameters a,b,cTABLE IValue of coefficients for a,b and c from [Park87]The Bartlett window reduces the overshoot in the designed filter but spreads the transition region considerably.The Hanning,Hamming and Blackman windows use progressively more complicated cosine functions to provide a smooth truncation ofthe ideal impulse response and a frequency response that looks better. The best window results probably come from using the Kaiser window, which has a parameter . that allows adjustment of the compromise between the overshoot reduction and transition region width spreading.The major advantages of using window method is their relative simplicity as compared to other methods and ease of use. The fact that well defined equations are often available for calculating the window coefficients has made this method successful.There are following problems in filter design using window method:(i) This method is applicable only if Hd(w) is absolutely integrable i.e only if (2) can be evaluated. When Hd(w) is complicated or cannot easily be put into a closed form mathematical expression, evaluation of hd(n) becomes difficult.(ii) The use of windows offers very little design flexibility e.g. in low pass filter design, the passband edge frequency generally cannot be specified exactly since the window smears the discontinuity in frequency. Thus the ideal LPF with cut-off frequency fc, is smeared by the window to give a frequency response with passband response with passband cutoff frequency f1 and stopband cut-off frequency f2.(iii) Window method is basically useful for design of prototype filters like lowpass,highpass,bandpass etc. This makes its use in speech and image processing applications very limited.The Frequency Sampling TechniqueIn this method, [Park87], [Rab75], [Proakis00] the desired frequency response is provided as in the previous method. Now the given frequency response is sampled at a set of equally spaced frequencies to obtain N samples. Thus , sampling the continuous frequency response Hd(w) at N points essentially gives us the N-point DFT of Hd(2pnk/N). Thus by using the IDFT formula, the filter co-efficients can be calculated using the following formula(12)Now using the above N-point filter response, the continuous frequency response is calculated as an interpolation of the sampled frequency response. The approximation error would then be exactly zero at the sampling frequencies and would be finite in frequencies between them. The smoother the frequency response being approximated, the smaller will be the error of interpolation between the sample points.One way to reduce the error is to increase the number of frequency samples [Rab75]. The other way to improve the quality of approximation is to make a number of frequency samples specified as unconstrained variables. The values of these unconstrained variables are generally optimized by computer to minimize some simple function of the approximation error e.g. one might choose as unconstrained variables the frequency samples that lie in a transition band between two frequency bands in which the frequency response is specified e.g. in the band between the passband and the stopband of a low pass filter.There are two different set of frequencies that can be used for taking the samples. One set of frequency samples are at fk = k/N where k = 0,1,….N-1. The other set of uniformly spaced frequency samples can be taken at fk =(k+1/2)/N for k = 0,1,….N-1.The second set gives us the additional flexibility to specify the desired frequency response at a second possible set of frequencies. Thus a given band edge frequency may be closer to type-II frequency sampling point that to type-I in which case a type-II design would be used in optimization procedure.In a paper by Rabiner and Gold [Rabi70], Rabiner has mentioned a technique based on the idea of frequency sampling to design FIR filters. The steps involved in this method suggested by Rabiner are as follows:(i) The desired magnitude response is provided along with the number of samples,N . Given N, the designer determines how fine an interpolation will be used.(ii) It was found by Rabiner that for designs they investigated, where N varied from 15 to 256, 16N samples of H(w) lead to reliable computations, so 16 to 1 interpolation was used.(iii) Given N values of Hk , the unit sample response of filter to be designed, h(n) is calculated using the inverse FFT algorithm.(iv) In order to obtain values of the interpolated frequency response two procedures were suggested by Rabiner.They are(a) h(n) is rotated by N/2 samples(N even) or (N-1)/2 samples for N odd to remove the sharp edges of impulse response, and then 15N zero-valued samples are symmetrically placed around the impulse response.(b) h(n) is split around the N/2nd sample, and 15N zero-valued samples are placed between the two pieces of the impulse response.(v) The zero augmented sequences are transformed using the FFT algorithm to give the interpolated frequency responses.Merits of frequency sampling technique(i) Unlike the window method, this technique can be used for any given magnitude response.(ii) This method is useful for the design of non-prototype filters where the desired magnitude response can take any irregular shape.There are some disadvantages with this method i.e the frequency response obtained by interpolation is equal to the desired frequency response only at the sampled points. At the other points, there will be a finite error present.Optimal Filter Design MethodsMany methods are present under this category. The basic idea in each method is to design the filter coefficients again and again until a particular error is minimized. The various methods are as follows:(i)Least squared error frequency domain design(ii)Nonlinear equation solution for maximal ripple FIR filters(iii)Polynomial interpolation solution for maximal ripple FIR filtersLeast squared error frequency domain designAs seen in the previous method of frequency sampling technique there is no constraint on the response between the sample points, and poor results may be obtained.The frequency sampling technique is more of an interpolation method rather than an approximation method. This method [Rab75], [Parks87] controls the response between the sample points by considering a number of sample points larger than the order of the filter.The purpose of most filters is to separate desired signals from undesired signals or noise. As the energy of the signal is related to the square of the signal, a squared error approximation criterion is appropriate to optimize the design of the FIR filters.The frequency response of the FIR filter is given by (8) for a N-point FIR filter. An error function is defined as follows(13) where wk=(2*pi*k)/L and Hd(wk) are L samples of the desired response, which is the error measure as a sum of the squared differences between the actual and desired frequency response over a set of L frequency samples. The method consists of the following steps:(i) First …L‟ samples from the continuous frequency response are taken, where L>N(length of the impulse response of filter to be designed)(ii) Then using the following formula(14) the L-point filter impulse response is calculated.(iii) Then the obtained filter impulse response is symmetrically truncated to desired length N.(iv) Then the frequency response is calculated using the following relation(15) (v) The magnitude of the frequency response at these frequency points for wk =(2k)/L will not be equal to the desired ones , but the overall least square error will be reduced effectively this will reduce the ripple in the filter response.To further reduce the ripple and overshoot near the band edges, a transition region will be defined with a linear transfer function. Then the L frequency samples are takenat wk =(2*pi*k)/L using which the first N samples of the filter are calculated using the above ing this method, reduces the ripple in the interpolated frequency response.Nonlinear Equation solution for maximal ripple FIR filters The real part of the frequency response of the designed FIR filter can be written as a(n)cos(wn) [Rab75] where limits of summation and a(n) vary according to the type of the filter. The number of frequencies at which H(w) could attain an extremum is strictly a function of the type of the linear phase filter i.e. whether length N of filter is odd or even or filter is symmetric or anti-symmetric. At each extremum, the value of H(w) is predetermined by a combination of the weighting function W(w), the desired frequency response, and a quantity that represents the peak error of approximation distributing the frequencies at which H(w) attains an extremal value among the different frequency bands over which a desired response was being approximated. Since these filters have the maximum number of ripples, they are called maximal ripple filters.This method is as follows:At each of the Ne unknown external frequencies, E(w) attains the maximum value of either and E(w) or equivalently H(w) has zero derivative. Thus two Ne equations of the formH(wi)= ±δ/W(w) + D(wi) (16)d/dw {H(wi)} at w=wi=0 (17) are obtained.These equations represent a set of 2Ne nonlinear equations in two Ne unknowns, Ne impulse response coefficients and Ne frequencies at which H(w) obtains the extremal value. The set of two Ne equations may be solved iteratively using nonlinear optimiation procedure.An important thing to note is that here the peak error (δ) is a fixed quantity and is not minimized by the optimization scheme. Thus the shape of H(w) is postulated apriori and only the frequencies at which H(w) attains the extremal values areunknown.The disadvantage of this method is that the design procedure has no way of specifying band edges for the different frequency bands of the filter. Thus the optimization algorithm is free to select exactly where the bands will lie. Polynomial Interpolation Solution for Maximal Ripple FIR filters This algorithm [Rab75] is basically an iterative technique for producing a polynomial H(w) that has extrema of desired values. The algorithm begins by making an initial estimate of the frequencies at which the extrema in H(w) will occur and then uses the well-known Lagrange interpolation formula to obtain a polynomial that alternatively goes through the maximum allowable ripple values at these frequencies. It has been experimentally found that the initial guess of extremal frequencies does not affect the ultimate convergence of the algorithm but instead affects the number of iterations required to achieve the desired result.Let us consider the case of design of a low pass filter using the above method.Fig. 1. Iterative solution for a maximum ripple lowpass filter from [Rab75]The Fig. 1 shows the response of a lowpass filter with N = 11.The number of extremal frequencies i.e. the frequencies where ripples occur are 6 in this case. They are divided into 3 passband extrema and 3 stopband extrema. The filled dots indicate the initial guess as to the extremal frequencies of H(w). The solid line is the initial Lagrange polynomial obtained by choosing polynomial coefficients so that the valuesof the polynomial at the guessed set of frequencies are identical to the assigned extreme values. But this polynomial has extrema that exceeds the specified maxima values. The next stage of the algorithm is to locate the frequencies at which the extrema of the first Lagrange interpolation occur. These frequencies are now used as the new frequencies for which the extrema of the filter response occur. This second set of frequencies are indicated by open dots in Fig. 1. Now similarly the new set of frequencies are taken as those frequencies where the maximum exceeds the specified maxima. Thus the method is completely iterative in nature.ConclusionsThe report has described the various techniques involved in the design of FIR filters. Every method has its own advantages and disadvantages and is selected depending on the type of filter to be designed.The window method is basically used for the design of prototype filters like the low-pass, high-pass, band-pass etc. They are not very suitable for designing of filters with any given frequency response. On the other hand, the frequency sampling technique is suitable for designing of filters with a given magnitude response. The ideal frequency response of the filter is approximated by placing appropriate frequency samples in the z -plane and then calculating the filter co-efficients using the IFFT algorithm.The disadvantage of the frequency sampling technique was that the frequency response gave errors at the points where it was not sampled. In order to reduce these erros the different optimization technique for FIR filter design were presented wherein the remaining frequency samples are chosen to satisfy an optimization criterion. An appendix consisting of the filter design methods used by the software package Matlab is also presented.References[Park87] T.W. Parks and C.S. Burrus, Digital Filter Design. New York:Wiley,1987 [Rab75] L.R. Rabiner and B. Gold, Theory and Applications of Digital Signal Processing. New Jersey: Prentice-Hall, 1975[Proakis00] J.G.Proakis and D.G. Manolakis, Digital Signal Processing Principles, Algorithms and Applications New Delhi: Prentice-Hall, 2000[Rab i70] L.R. Rabiner, B. Gold and C.A. McGonegal, “An approach to the Approximation Problem for Nonrecursive Digital Filters,” IEEE Trans. Audio and Electroacoustics, vol. AU-18, pp. 83-105,June 1970.[Mat02]/access/helpdesk/help/toolbox/signal/signal.shtml Signal Processing Toolbox,The Mathworks,Inc., accessed October 25,2002外文翻译FIR滤波器设计技术摘要这份报告列举了一些设计FIR滤波器所使用的技术。

消费者行为心理学中英文外文文献翻译

消费者行为心理学中英文外文文献翻译

消费者行为心理学中英文外文文献翻译(含：英文原文及中文译文)英文原文Frontiers of Social PsychologyArie W. Kruglanski 、Joseph P. ForgasFrontiers of Social Psychology is a new series of domain-specific handbooks. The purpose of each volume is to provide readers with a cutting-edge overview of the most recent theoretical, methodological, and practical developments in a substantive area of social psychology, in greater depth than is possible in general social psychology handbooks. The editors and contributors are all internationally renowned scholars whose work is at the cutting-edge of research.Scholarly, yet accessible, the volumes in the Frontiers series are an essential resource for senior undergraduates, postgraduates, researchers, and practitioners, and are suitable as texts in advanced courses in specific subareas of social psychology.Some Social Asp ects of Living in a Consumer SocietyThe following sketches will illustrate that in a consumer society much of the behavior studied by social psychologists relates to consumer stimuli and consumer behavior. Thus, the consumer context provides a rich field for the study of social phenomena and behavior.Consumer Decisions Are UbiquitousWhether we are in the supermarket or not, we are constantly making consumer decisions. We enroll in gyms, use our frequent-flyer miles for a vacation resort, buy health care, choose a restaurant, skip dessert for a healthier lifestyle. In fact, most of our daily decisions do not involve existential decisions such as whom to marry or whether to have children or not, but whether to have tea or coffee, use our credit card or pay cash, or other seemingly trivial decisions. Moreover, many of our daily (consumer) behaviors do not even require intentional decisions. Rather, they may be habitual, such as switching to CNN to get the news or accessing Google when looking up some information. A typical day of a typical person is filled with countless minor consumer decisions or the consequences of previous decisions, starting with the brand of toothpaste in the morning to choosing a movie after work.Consumer Choices Fulfill a Social-Identity FunctionAlthough for most people being a consumer may not be central to their identity, many of their consumer decisions are nevertheless highly identity-relevant insofar as they correspond to a larger set of values and beliefs and express important aspects of the self. Eating a vegetarian diet because one does not want to endorse cruelty to animals and boycotting clothes potentially made by child laborers are some examples. Some people buy a Prius out of environmental concerns; others boycott Japanese cars —such as the Prius —in order to help the local carindustry. In this respect, even the choice between Coke and Pepsi is not necessarily trivial. People who cannot discriminate Coke from Pepsi in a blind test, or who prefer Pepsi, may nevertheless adhere to Coke as a cultural icon. Attempts to change the formula of Coke met with angry protests and opposition. Clearly, consumer products and brands do not only fulfill utilitarian needs (Olson & Mayo, 2000; Shavitt, 1990). In a world of oversupply and differentiating brands, many consumers choose brands in order to express their personality or to affiliate themselves with desired others. They do not simply use a Mac; they are Mac users, and switching to another brand of PC would be akin to treason. From soft drinks to computers, brands may become an ideology. People may also perceive of products as extended selves (Belk, 1988); for example, they may identify with their cars just as they do with pets. Likewise, brands may define social groups. The Harley-Davidson Club is a legendary example; an Internet search revealed clubs for almost every car brand and model. In my hometown, I found a V olkswagen New Beetle Club whose stated purpose is to cultivate contacts between New Beetle Drivers by organizing social events (among others, a visit to a car cemetery). On the road, drivers of the same car model often greet each other. Apparently, driving the same model is sufficient to establish social closeness. Brands, products, and consumption habits not only help to establish social connectivity but also serve as status symbols, defining vertical andhorizontal social boundaries. By using particular brands or consuming specific products, people can express a certain lifestyle or attempt to convey a particular social impression. Subscribing to the opera conveys one’s social position just as going to a monster truck race does. Whether your choice of drink is wine or beer, cappuccino or herbal tea, your order expresses more than merely your taste in beverages.Consumer Choices Affect Social PerceptionGiven that brands and products are part of social expression, it is not surprising that people are judged by the brands and products they use. In particular, products of a social-identity function are used as bases for inferences about a target’s personality traits (Shavitt & Nelson, 2000). Likewise, smoking, food choice and amount of food intake have all been shown to affect social impressions. Depending on the subculture of the perceiver (age, country), different personality traits are assumed in smokers compared with nonsmokers (e.g., Cooper & Kohn, 1989; Jones & Carroll, 1998). Various studies found that eaters of a healthier diet are perceived as more feminine and in general judged more favorably than eaters of unhealthy foods (for a review see V artanian, Herman, & Polivy, 2007). Arguing that a Pepsi drinker is to a Coke drinker what a Capulet was to a Montague is, of course, an exaggeration, but clearly brands may distinguish ingroup from out-group members. Possibly this is most extreme among teenagers, where the brand of jeans is perceived todetermine coolness and popularity. Nevertheless, the phenomenon is not limited to teen culture, as testified by the previous examples of social communities defined by shared brands. In sum, from wet versus dry shaving to driving a Porsche versus a Smart, consumer behavior is used as a cue in person perception. Most likely, such cues also manifest in behavior toward these consumers. Physical attacks on women who wear fur are a most extreme example.Affective Consequences of Consumer BehaviorObviously, consumption and the use of products and services may give pleasure and satisfaction or displeasure and dissatisfaction. People may experience joy from wearing a new sweater or suffer emotional consequences when products or services fail or cause inconvenience. Product use is only one source of affective consumer experiences. The mere act of choosing and acquisition is another. People enjoy or dislike the experience of shopping. They may take pleasure from the freedom of simply choosing between different options (e.g., Botti & Iyengar, 2004), feel overwhelmed and confused by an abundance of options (e.g., Huffman & Kahn, 1998), or feel frustrated by a limited assortment that does not meet their particular needs (e.g., Chernev, 2003). They may experience gratification and a boost in self-esteem from the fact that they can afford a particular consumer lifestyle or grudge the fact that they cannot. Many daily sources of affective experiences involve consumerbehavior in one way or another.The Consumer Context Provides Unique Social InteractionsGranted, we rarely form deep and meaningful relationships with our hairdressers and waiters. Still, the consumer context affords many social interactions over a day. Again, these interactions— even if brief— may constitute a source of affective experiences. The smile of the barista, the compliment from the shop-assistant, and the friendly help from the concierge are just a few examples of how such consumerrelated interactions may make us feel good, worthy, and valued, whereas snappy and rude responses have the opposite effect. Besides, the social roles defined by the consumer context may provide unique opportunities for particular behaviors, interactions, and experiences not inherent in other roles. Being a client or customer makes one expect respect, courtesy, and attendance to one’s needs. For some, this may be the only role in their life that gives them a limited sense of being in charge and having others meet their demands. To give another example, complaining is a form of social interaction that mostly takes place within the consumer context. A search for ―complaint behavior‖ in the PsycI NFO database found that 34 out of 50 entries were studies from the consumer context. (The rest mostly related to health care, which may to some extent also be viewed as consumer context.) Given the importance of the consumer context to social experiences and interactions, it provides a prime opportunity forstudying these social behaviors.•How consumers think, feel, reason, and the psychology of screening for different items (such as brands, products); • Consumer behavior when they shop or make other marketing decisions;•Limits in consumer knowledge or access to information affect decisions and marketing outcomes;•How can marketers adapt and improve their marketing competitiveness and marketing strategies to attract consumers more efficiently?Bergi gives an official definition of consumer behavior: the process and the activities people perform when they research, select, purchase, use, evaluate, and deal with products and services in order to meet their needs. The behavior occurs in a group or an organization where individuals or individuals appear in this context. Consumer behavior includes using and handling products and studying how products are bought. The use of products is generally of great interest to marketers because it may affect how a product is in the best position or how we can encourage increased consumption.The Nicosia model focuses on the relationship between the company and its potential customers. The company communicates with consumers through its marketing messages or advertisements and consumers' reactions to the information they want to buy. Seeing this pattern, we willfind that companies and consumers are interconnected. Companies want to influence consumers. Consumers influence company decisions through their decisions.Consumer sentiment refers to a unique set of emotional reactions to the use of or eliciting a consumer experience in the product, a unique class or relationship of the emotional experience described and expressed (such as joy, anger and fear), such as the structural dimensions of the emotional category or pleasant/unpleasant, Relax/action, or calm/excited. Goods and services are often accompanied by emotional reactions (such as the fear caused by watching a horror movie). Emotional values are often associated with aesthetic choices (such as religion, reason). However, more material and utilitarian products also seem to have emotional value. For example, some foods cause childhood experiences and feel comfortable with them. Izad (1977) developed a method of emotional experience and introduced basic emotions. He uses ten words to distinguish the basic types of emotions: interest, joy, surprise, sadness, anger, disgust, contempt, fear, shame, and guilt. This method has been widely used by consumer research.In order to implement the interpersonal and personal construction in this framework, we use the concept of self-awareness to express the influence of consumer response on society. Self-awareness is defined as the individual's consistent trend to focus directly on inward or outward.This theory identifies two different types of people with self-consciousness. The open self-conscious person pays special attention to other people's views on their outside. The private self-conscious person pays more attention to their inner thoughts and feelings. In this case, we assume that the reputation of consumption may be different based on sensitivity to other people. This proposal is also consistent with previous research. It shows that people with different personal behaviors depend on their sensitivity to interpersonal influences. Dubois and Dikena emphasized that "we believe that the analysis of the direct relationship between consumers and brands is a key to improving understanding of such a market." This original assumption is that of private or The value of the open superior product comes from the inherent social status of these objects. Many existing studies emphasize the role of the role played in the exchange of information about their owners and social relationships.中文译文社会心理学前沿艾瑞·克鲁格兰斯基，约瑟夫·弗加斯社会心理学的前沿是一个新的领域专用手册系列。

机械工程专业外文文献及翻译

机械工程专业外文文献及翻译

机械工程专业外文文献及翻译文献一（外文标题）
摘要：
该文献研究了机械工程领域中的某个具体问题。

通过实验方法和数学模型的分析，作者得出了一些有意义的结论。

本文介绍了作者的研究方法和结果，并讨论了其在机械工程领域的应用前景。

翻译：
（将文献的主要内容用简洁准确的语言翻译成中文）
文献二（外文标题）
摘要：
该文献探讨了机械工程领域中的另一个重要问题。

通过实证分析和理论推导，作者提出了解决方案，并对其进行了验证。

本文阐述了作者的方法和实验结果，并探讨了其在实践中的应用潜力。

翻译：
（将文献的主要内容用简洁准确的语言翻译成中文）
文献三（外文标题）
摘要：
该文献研究了机械工程领域中的另一个新颖课题。

作者通过数
值模拟和实验验证，得出了一些有趣的发现。

本文介绍了作者的研
究过程和结果，并讨论了其对机械工程领域的影响。

翻译：
（将文献的主要内容用简洁准确的语言翻译成中文）
总结
本文档介绍了三篇机械工程专业的外文文献，包括摘要和翻译。

这些文献都对机械工程领域中的不同问题进行了研究，并提出了相
关的解决方案和发现。

希望这些文献能为机械工程专业的学生和研
究人员提供有价值的参考和启发。

毕业设计外文文献翻译(原文+译文)

毕业设计外文文献翻译(原文+译文)

Environmental problems caused by Istanbul subway excavation and suggestionsfor remediation伊斯坦布尔地铁开挖引起的环境问题及补救建议Ibrahim Ocak Abstract：Many environmental problems caused by subway excavations have inevitably become an important point in city life. These problems can be categorized as transporting and stocking of excavated material, traffic jams, noise, vibrations, piles of dust mud and lack of supplies. Although these problems cause many difficulties,the most pressing for a big city like Istanbul is excava tion,since other listed difficulties result from it. Moreover, these problems are environmentally and regionally restricted to the period over which construction projects are underway and disappear when construction is finished. Currently, in Istanbul, there are nine subway construction projects in operation, covering approximately 73 km in length; over 200 km to be constructed in the near future. The amount of material excavated from ongoing construction projects covers approximately 12 million m3. In this study, problems—primarily, the problem with excavation waste(EW)—caused by subway excavation are analyzed and suggestions for remediation are offered.摘要：许多地铁开挖引起的环境问题不可避免地成为城市生活的重要部分。

室内装饰装修设计外文文献翻译中英文

室内装饰装修设计外文文献翻译中英文

外文文献翻译(含：英文原文及中文译文)文献出处：Y Miyazaki. A Brief Description of Interior Decoration [J]. Building & Environment, 2005, 40(10):41-45.英文原文A Brief Description of Interior DecorationY Miyazaki一、An interior design element1 Spatial elementsThe rationalization of space and giving people a sense of beauty is the basic task of design. We must dare to explore the new image of the times and technologies that are endowed with space. We should not stick to the spatial image formed in the past.2 color requirementsIn addition to affecting the visual environment, indoor colors also directly affect people's emotions and psychology. Scientific use of color is good for work and helps health. The proper color processing can meet the functional requirements and achieve the beauty effect. In addition to observing the general laws of color, interior colors also vary with the aesthetics of the times.3 light requirementsHumans love the beauty of nature and often direct sunlight into theinterior to eliminate the sense of darkness and closure in the interior, especially the top light and the soft diffuse light, making the interior space more intimate and natural. The transformation of light and shadow makes the interior richer and more colorful, giving people a variety of feelings.4 decorative elementsThe indispensable building components such as columns, walls, and the like in the entire indoor space are combined with the function and need to be decorated to jointly create a perfect indoor environment. By making full use of the texture characteristics of different decorative materials, you can achieve a variety of interior art effects with different styles, while also reflecting the historical and cultural characteristics of the region.5 furnishingsIndoor furniture, carpets, curtains, etc., are all necessities of life. Their shapes are often furnished and most of them play a decorative role. Practicality and decoration should be coordinated with each other, and the functions and forms of seeking are unified and changed so that the interior space is comfortable and full of personality.6 green elementsGreening in interior design is an important means to improve the indoor environment. Indoor flowering trees are planted, and the use ofgreenery and small items to play a role in diffusing indoor and outdoor environments, expanding the sense of interior space, and beautifying spaces all play an active role.二、The basic principles of interior design1 interior decoration design to meet the functional requirementsThe interior design is based on the purpose of creating a good indoor space environment, so as to rationalize, comfort, and scientize the indoor environment. It is necessary to take into account the laws of people's activities to handle spatial relationships, spatial dimensions, and spatial proportions; to rationally configure furnishings and furniture, and to properly resolve indoor environments. V entilation, lighting and lighting, pay attention to the overall effect of indoor tone.2 interior design to meet the spiritual requirementsThe spirit of interior design is to influence people's emotions and even influence people's will and actions. Therefore, we must study the characteristics and laws of people's understanding; study the emotions and will of people; and study the interaction between people and the environment. Designers must use various theories and methods to impact people's emotions and sublimate them to achieve the desired design effect. If the indoor environment can highlight a certain concept and artistic conception, then it will have a strong artistic appeal and better play its role in spiritual function.3 Interior design to meet modern technical requirementsThe innovation of architectural space is closely related to the innovation of structural modeling. The two should be harmonized and unified, fully considering the image of the structural Sino-U.S. and integrating art and technology. This requires that interior designers must possess the necessary knowledge of the type of structure and be familiar with and master the performance and characteristics of the structural system. Modern interior design is in the category of modern science and technology. To make interior design better meet the requirements of spiritual function, we must maximize the use of the latest achievements in modern science and technology.4 Interior design must meet the regional characteristics and national style requirementsDue to differences in the regions where people live, geographical and climatic conditions, the living habits of different ethnic groups are not the same as cultural traditions, and there are indeed great differences in architectural styles. China is a multi-ethnic country. The differences in the regional characteristics, national character, customs, and cultural literacy of various ethnic groups make indoor decoration design different. Different styles and features are required in the design. We must embody national and regional characteristics to evoke people’s national self-respect and self-confidence.三、Points of interior designThe interior space is defined by the enclosure of the floor, wall, and top surface, thus determining the size and shape of the interior space. The purpose of interior decoration is to create a suitable and beautiful indoor environment. The floor and walls of the interior space are the backdrop for people and furnishings and furnishings, while the differences on the top surface make the interior space more varied.1 Base decoration ----- Floor decorationThe basic surface ----- is very important in people's sights. The ground floor is in contact with people, and the line of sight is near, and it is in a dynamic change. It is one of the important factors of interior decoration. Meet the following principles:2 The base should be coordinated with the overall environment to complement each other and set off the atmosphereFrom the point of view of the overall environmental effect of space, the base should be coordinated with the ceiling and wall decoration. At the same time, it should play a role in setting off the interior furniture and furnishings.3 Pay attention to the division, color and texture of the ground patternGround pattern design can be roughly divided into three situations: The first is to emphasize the independent integrity of the pattern itself,such as meeting rooms, using cohesive patterns to show the importance of the meeting. The color should be coordinated with the meeting space to achieve a quiet, focused effect; the second is to emphasize the pattern of continuity and rhythm, with a certain degree of guidance and regularity, and more for the hall, aisle and common space; third It emphasizes the abstractness of the pattern, freedom, and freedom, and is often used in irregular or layout-free spaces.4 Meeting the needs of the ground structure, construction and physical properties of the buildingWhen decorating the base, attention should be paid to the structure of the ground floor. In the premise of ensuring safety, it is convenient for construction and construction. It cannot be a one-sided pursuit of pattern effects, and physical properties such as moisture-proof, waterproof, thermal insulation, and thermal insulation should be considered. need. The bases are available in a wide variety of types, such as: wooden floors, block floors, terrazzo floors, plastic floors, concrete floors, etc., with a wide variety of patterns and rich colors. The design must be consistent with the entire space environment. Complementary to achieve good results.四、wall decorationIn the scope of indoor vision, the vertical line of sight between the wall and the person is in the most obvious position. At the same time, thewall is the part that people often contact. Therefore, the decoration of the wall is very important for the interior design. The following design principles must be met: 1 IntegrityWhen decorating a wall, it is necessary to fully consider the unity with other parts of the room, and to make the wall and the entire space a unified whole.2 PhysicalThe wall surface has a larger area in the interior space, and the status is more important and the requirements are higher. The requirements for sound insulation, warmth protection, fire prevention, etc. in the interior space vary depending on the nature of the space used, such as the guest room, high requirements. Some, while the average unit canteen, requiresa lower number.3 ArtistryIn the interior space, the decorative effect of the wall plays an important role in rendering and beautifying the indoor environment. The shape of the wall, the partition pattern, the texture and the interior atmosphere are closely related to each other. In order to create the artistic effect of the interior space, the wall The artistry of the surface itself cannot be ignored.The selection of wall decoration styles is determined according to the above principles. The forms are roughly the following: plasteringdecoration, veneering decoration, brushing decoration, coil decoration. Focusing on the coil decoration here, with the development of industry, there are more and more coils that can be used to decorate walls, such as: plastic wallpaper, wall cloth, fiberglass cloth, artificial leather, and leather. These materials are characterized by the use of It is widely used, flexible and free, with a wide variety of colors, good texture, convenient construction, moderate prices, and rich decorative effects. It is a material that is widely used in interior design.五、Ceiling decorationThe ceiling is an important part of the interior decoration, and it is also the most varied and attractive interface in the interior space decoration. It has a strong sense of perspective. Through different treatments, the styling of lamps and lanterns can enhance the space appeal and make the top surface rich in shape. Colorful, novel and beautiful.1 Design principlesPay attention to the overall environmental effects.The ceiling, wall surface and base surface together make up the interior space and jointly create the effects of the indoor environment. The design should pay attention to the harmonization of the three, and each has its own characteristics on a unified basis.The top decoration should meet the applicable aesthetic requirements.In general, the effect of indoor space should be lighter and lighter. Therefore, it is important to pay attention to the simple decoration of the top decoration, highlight the key points, and at the same time, have a sense of lightness and art.The top decoration should ensure the rationality and safety of the top structure. Cannot simply pursue styling and ignore safety2 top design(1) Flat roofThe roof is simple in construction, simple in appearance, and convenient in decoration. It is suitable for classrooms, offices, exhibition halls, etc. Its artistic appeal comes from the top shape, texture, patterns, and the organic configuration of the lamps.(2) Convex ceilingThis kind of roof is beautiful and colorful, with a strong sense of three-dimensionality. It is suitable for ballrooms, restaurants, foyers, etc. It is necessary to pay attention to the relationship between the primary and secondary relationships and the height difference of various concavo-convex layers. It is not appropriate to change too much and emphasize the rhythm of rhythm and the artistry of the overall space. .(3) Suspended ceilingV arious flaps, flat plates or other types of ceilings are hung under the roof load-bearing structures. These ceilings are often used to meetacoustic or lighting requirements or to pursue certain decorative effects. They are often used in stadiums, cinemas, and so on. In recent years, this type of roof has also been commonly used in restaurants, cafes, shops, and other buildings to create special aesthetics and interests.(4) Well format ceilingIt is in the form of a combined structural beam, in which the main and secondary beams are staggered and the relationship between the wells and beams, together with a ceiling of lamps and gypsum floral designs, is simple and generous, with a strong sense of rhythm.(5) Glass ceilingThe halls and middle halls of modern large-scale public buildings are commonly used in this form, mainly addressing the needs of large-scale lighting and indoor greening, making the indoor environment richer in natural appeal, and adding vitality to large spaces. It is generally in the form of a dome, a cone, and a zigzag. In short, interior decoration design is a comprehensive discipline, involving many disciplines such as sociology, psychology, and environmental science, and there are many things that we need to explore and study. This article mainly elaborated the basic principles and design methods of interior decoration design. No matter what style belongs to the interior design door, this article gives everyone a more in-depth understanding and comprehension of interior design. If there are inadequacies, let the criticism correct me.中文译文室内装饰简述Y Miyazaki一室内装饰设计要素1 空间要素空间的合理化并给人们以美的感受是设计基本的任务。

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华 北 电 力 大 学 科 技 学 院 毕 业 设 计（论 文）附 件 外 文 文 献 翻 译

学 号： 121912020115 姓 名： 彭钰钊 所在系别： 动力工程系 专业班级： 测控技术与仪器12K1 指导教师： 李冰 原文标题： Infrared Remote Control System Abstract

2016 年 4 月 19 日w 红外遥控系统

摘 要 红外数据通信技术是目前在世界范围内被广泛使用的一种无线连接技术，被众多的硬件和软件平台所支持。红外收发器产品具有成本低，小型化，传输速率快，点对点安全传输，不受电磁干扰等特点，可以实现信息在不同产品之间快速、方便、安全地交换与传送，在短距离无线传输方面拥有十分明显的优势。红外遥控收发系统的设计在具有很高的实用价值，目前红外收发器产品在可携式产品中的应用潜力很大。全世界约有1亿5千万台设备采用红外技术，在电子产品和工业设备、医疗设备等领域广泛使用。绝大多数笔记本电脑和手机都配置红外收发器接口。随着红外数据传输技术更加成熟、成本下降，红外收发器在短距离通讯领域必将得到更广泛的应用。 本系统的设计目的是用红外线作为传输媒质来传输用户的操作信息并由接收电路解调出原始信号，主要用到编码芯片和解码芯片对信号进行调制与解调，其中编码芯片用的是台湾生产的PT2262，解码芯片是PT2272。主要工作原理是：利用编码键盘可以为PT2262提供的输入信息，PT2262对输入的信息进行编码并加载到38KHZ的载波上并调制红外发射二极管并辐射到空间，然后再由接收系统接收到发射的信号并解调出原始信息，由PT2272对原信号进行解码以驱动相应的电路完成用户的操作要求。

关键字：红外线；编码；解码；LM386；红外收发器。

1 绪论 w 1．1 课题研究的背景及意义 红外数据通信技术是目前在世界范围内被广泛使用的一种无线连接技术，被众多的硬件和软件平台所支持。是一种通过数据电脉冲和红外光脉冲之间的相互转换实现无线的数据收发的技术。 红外收发器产品具有成本低，小型化，传输速率快，点对点安全传输，不受电磁干扰等特点，可以实现信息在不同产品之间快速、方便、安全地交换与传送，在短距离无线传输方面拥有十分明显的优势。 红外收发器产品在可携式产品中的应用作用很大。目前，全世界有1亿5千万台设备采用红外技术，在电子产品和工业设备、医疗设备等领域广泛使用。比如有95％的笔记本电脑就安装了红外收发器接口,现在绝大多数手机上也配置红外收发器接口。而且随着交换的数据量变大，红外数据通讯将使手机的数据传输越来越方便。随着红外数据传输技术越来越成熟、完善、成本更低廉，红外收发器在短距离通讯领域必将得到更广泛的应用。 本章首先阐述了红外收发集成电路设计课题的背景和意义，然后简要介绍了红外数据通讯技术的特点和应用领域，以及红外收发器产品的特点、国内外现状和发展趋势，最后根据红外遥控收发系统的实际应用性确立了课题的设计定位。 1．2 红外遥控收发系统简介

红外遥控系统分为单通道遥控和多通道遥控。只有一个指令信号传送通道的称为单通道遥控系统;具有两个以上指令信号传送通道的称为多通道遥控系统。单通道遥控比较简单 ,一般来说 ,发射器仅有一个指令键 ,接收器也只有一个执行电路。虽然在接收电路中加入多稳态记忆电路 ,可以根据按动发射器指令键的次数 ,使接收电路中的多稳态记忆电路的状态多次改变 ,实现多项功能控制 ,但是这种状态的改变是顺序进行的。如果要实现一项任意控制 ,就要采用多通道遥控系统。多通道遥控可以实现对被控对象的任意多功能遥控。至于选用几个通道及何种控制方式 ,要根据实际情况(如被控对象、操作要求及成本核算等)来决定。一般的红外遥控收发系统是由红外遥控信号编码发送器、红外遥控信号接收器和解码器（解码芯片或单片机）及其外围电路等三部分构成的。信号发送器用来产生遥控编码脉冲，驱动红外w 发射管输出红外遥控信号，接收器完成对遥控信号的放大、检波、整形并解调出编码脉冲。红外遥控编码脉冲是一组组连续的串行二进制码，对于一般的红外收发系统，此串行码作为微控制器的遥控输入信号，由其内部CPU完成对遥控指令的解码，对其他各种红外遥控收发电子产品的设计者来说，上述的微控制器内部解码出的遥控指令是不便于利用的。因此，人们利用红外编/解码芯片及单片机研制出多种通用红外遥控收发系统，在各种设备之间进行红外信号的收发。 遥控收发系统一般由发射器和接收器两部分组成。发射器一般由指令键、指令编码电路、调制电路、驱动电路、发射电路等几部分组成。当按下某键时 ,指令编码电路,产生相应的指令编码信号 ,编码指令信号对载波进行调制 ,再由驱动电路进行功率放大之后由发射电路向外发射经过调制的指令编码信号。接收器一般由接收电路、放大电路、解调电路、指令译码电路、驱动电路、执行电路等几部分组成。接收电路将发射器发射的已调制的编码指令信号接收下来 ,并进行放大后送解调电路。解调电路将已调制的编码信号解调下来 ,即还原为编码信号。指令译码器将编码指令信号进行译码 ,最后由驱动电路来驱动执行电路实现各种指令的操作控制。 1．3 红外遥控收发器产品概况

1.3.1红外遥控收发器产品的结构和类型 目前红外收发器按照工作模式和传输速率可分为四类：串行模式，最高速率为115.2Kbps；中速模式：最高速率为0.567Mbps和1.152Mbps；高速模式：最高速率为16Mbps。 另外按芯片功耗大小又可以分为低功耗型和标准型两类，低功耗型通常使用3V电源，传输距离较近，约0-30cm，标准型通常使用5V电源，传输距离较远最少1m以上。 1.3.2红外遥控收发器的国内外现状

在红外通信技术发展的早期，存在好几个红外通信标准，不同标准之间红外设备不能进行红外通信。为了使各种红外设备能够互联互通，1993年由20多个大厂商发起成立了红外数据协会（IRDA）统一了红外通信的标准，这就是目前被广泛使用的红外数据通信协议及规范，也称为IRDA标准。 w 自1993年IRDA成立至今，红外数据协会的会员已经发展到150多个，IRDA标准已经获得了业界广泛认同和支持。已经开发出来的具备红外通讯能力的设备已经有一百多种之多，红外模块的年装机量已经达到一亿五千万套。尽管现在有了同样是近距离无线通讯的蓝牙技术，但以红外通讯技术低廉的成本和广泛的兼容性的优势，红外数据通讯仍旧会在将来很长一段时间内在短距离的无线数据通讯领域扮演重要角色。 由IRDA协会的资料表明，国外公司的红外收发器产品起步较早，已经形成了红外收发器的配套生产产业链。由以下部分组成：Sharp等公司主要提供红外发光二极管和光敏二极管；Agilent等公司主要设计制作红外收发芯片；Infineon等公司主要从事红外收发器封装；IBM、Microsoft等公司则推出红外数据收发器驱动程序和红外通信软件。其中如Agilent等公司还具有生产红外收发器系列产品的能力，而HP、IBM等大公司则专门为自己公司产品配备红外收发器。 在中国台湾地区也形成了一批红外收发产品的生产厂家和公司，但在大陆地区只有一些器件销售公司在做这些国际公司和台湾公司的代理，缺乏具有自主产权的该类产品。 1.3.3红外收发器产品的发展趋势

在各种红外收发器产品中，虽然传输速率、传输距离等特性不同，但红外收发器产品一直朝着提高传输速率，增加传输距离，降低功耗，扩大发射接收角度等方面发展。特别是随着技术发展和成熟，传输方式正朝着点对多点方向发展。因此红外遥控收发器产品还有更加宽广的发展前景。

2 红外通信的基础知识 2．1红外线基础知识 2.1.1红外线概述 红外线实质上是一种电磁波。从分析自然界中各种电磁波组成的波可知，波谱是由 ：射线，ｘ射线、紫外线、可见光、红外线、微波和无线波组成的。从形式上w 看，它们之间似乎没有关系，但如果按照他们的波长依次排列，就会发现和我们形影不离的可见光只占了整个波谱中0.38μm-0.76μm长的这么一点儿范围，而和可见光相邻的红外线 （包括远红外线、中红外线和近红外线外）却占了波谱中0.76μm-1000μm的一大段。其中微米波长范围内又包括了紫外光 、可见光、近红外、中红外 、远红外、微波。 从上述分析可知，红外线是一种十分丰富的波谱资源，目前它己在生产、生活、军事、医疗等多方面得到了广泛的应用，例如红外线加热、红外线医疗期间、红外线通信、红外线摄像、红外线遥控等。红外线遥控只是红外线 众多应用中的一部分，目前在家用电器中广泛应用的彩电遥控器、录像机遥控器、 VCD遥控器、高保真音响遥控器等，都采用了红外线遥控，它使这些家用电器的控制变得十分简单方便。 2.1.2红外线的特性

红外线是介于可见光和微波之间的一种电磁波，因此它具有相临波的某些特性。在近红外区，它和可见光相邻，因此具有可见光的某些特性，如直线传播、反射、折射、散射、衍射、可被某些物体吸收以及可以通过透镜将其聚焦等。在远红外区，由于它邻近微波区，因此它具有微波的某些特性，如较强的穿透能力和能贯穿某些不透明物质等。在自不论任何物体，然界中，也不论其本身是否发光 （指可见光） 只要其温度高于绝对零度 （-273℃），都会一刻不停地向周围辐射红外线。只不过是温度较高的物体辐射的红外线较强，温度低的物体辐射的红外线较弱。因此红外线的最大特点是普遍存在于自然界中，又叫做热辐射线简称热辐射。红外线摄像、红外线夜市、热释电红外探测以及某些导弹的瞄准等就是利用红外线的这一特性工作的。 红外线和可见光相比的另一个特点是，色彩丰富多样。由于可见光的最长波长是最短波长的1倍（780nm-380nm），所以也叫作一个倍频程。而红外线的最长波长是最短波长的1倍，而红外线的最长波长是最短波长的10倍，即有10个倍频程。因此如果可见光能表现为7种颜色，则红外线便可能表现70种颜色，显示了丰富的色彩。红外线透过烟雾的性能好，这是它的又一个特点。 由于红外线为不可见光 ,因此对环境影响很小。再由红外光波的波长远小于无

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