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急求字有关电脑方面的英语文章连接!英文网站 英文文章 3000字 30个 单词翻译 10个 句子翻译 全文翻译 这是要求
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REDUCED INSTRUCTION
SET COMPUTERS
Studies of the execution behavior of high-level language programs have provided guidance in designing a new type of processor architecture：the reduced instruction set computer（RISC）．Assignment statements predominate,suggesting that the simple movement of data should be optimized．There are also many IF and LOOP instructions,which suggest that the underlying sequence control mechanism needs to be optimized to permit efficient pipelining．Studies of operand reference patterns suggest that it should be possible to enhance performance by keeping a moderate number of operands in registers．
These studies have motivated the key characteristics of RISC machines：（1）a limited instruction set with a fixed format．（2）a large number of registers or the use of a compiler that optimizes register usage,and（3）an emphasis on optimizing the instruction pipeline．
The simple instruction set of a RISC lends itself to efficient pipelining because there are fewer and more predictable operations performed per instruction．[1] A RISC instruction set architecture also lends itself to the delayed branch technique,in which branch instructions are rearranged with other instructions to improve pipeline efficiency．
Although RISC systems have been defined and designed in a variety of ways by different groups,the key elements shared by most designs are these：
．A large number of general-purpose registers,or the use of compiler technology to optimize register usage
．A limited and simple instruction set
．An emphasis on optimizing the instruction pipeline
Table 2-1 compares several RISC and non-RISC systems.
1．Instruction Execution Characteristics
To understand the line of reasoning of the RISC advocates,we begin with a brief review of instruction execution characteristics．The aspects of computation of interest are as follows：
Operations performed：These determine the functions to be performed by the processor and its interaction with memory．
Operands used：The types of operands and the frequency of their use determine the memory organization for storing them and the addressing modes for accessing them．
Execution sequencing：This determines the control and pipeline organization．
2．The Use of A Large Register File [2]
The reason that register storage is indicated is that it is the fastest available storage device,faster than both main memory and cache．The register file is physically small,generally on the same chip as the ALU and control unit,and employs much shorter addresses than addresses for cache and memory．Thus,a strategy is needed that will allow the most frequently accessed operands to be kept in registers and to minimize register-memory operations．
Two basic approaches are possible,one based on software and the other on hardware．The software approach is to rely on the compiler to maximize register usage．The compiler will attempt to allocate registers to those variables that will be used the most in a given time period．This approach requires the use of sophisticated programanalysis algorithms．The hardware approach is simply to use more registers so that more variables can be held in registers for longer periods of time．
3．Characteristics of Reduced Instruction Set Architectures
Although a variety of different approaches to reduced instruction set architecture have been taken,certain characteristics are common to all of them．These characteristics are listed in Table 2．1 and described here．
The first characteristic listed in Table 2．1 is that there is one machine instruction per machine cycle．A machine cycle is defined to be the time it takes to fetch two operands from registers,perform an ALU operation,and store the result in a register．Thus,RISC machine instructions should be no more complicated than,and execute about as fast as,microinxtructions on CISC machines．[3] With simple,one –cycle instructions,there is little or no need for microcode；the machine instructions can be hardwired[4]．Such instructions should execute faster than comparable machine instructions on other machines,since it is not necessary to access a microprogram control store during instruction execution．
A second characteristic is that most operations should be register-to-register,with only simple LOAD and STORE operations accessing memory．This design feature simplifies the instruction set and therefore the control unit．For example,a RISC instruction set may include only one or two ADD instructions（e. g. ,integer add,add with carry）；the VAX has 25 different ADD instructions．Another benefit is that such an architecture encourages the optimization of register use,so that frequently accessed operands remain in high-speed storage．
Returning to Table 2-1,a third characteristic is the use of simple addressing modes．Almost all instructions use simple register addressing．Several additional modes,such as displacement and PC-relative,may be included．Other,more complex modes can be synthesized in software from the simple ones．Again,this design feature simplifies the instruction set and the control unit．
A final common characteristic is the use of simple instruction formats．Generally,only one or a few formats are used．Instruction length is fixed and aligned on word boundaries．Field locations,especially the opcode,are fixed．This design feature has a number of benefits．With fixed fields,opcode decoding and register operand accessing can occur simultaneously．Simplified formats simplify the control unit．Instruction fetching is optimized since word-length units are fetched．This also means that a single instruction does not cross page boundaries．
[1] lend itself to适合于…
[2] register file寄存器组,作为数据或指令的临时存放处的一种多位寄存器组,有时称作栈.
[3] 此句为比较结构no more... than…,中间插入并列句将被比较对象隔开了.
[4] hardwired硬连线的,即机器指令是固化在硬件（芯片）上的.
instruction set 指令系统,指令集
reduced instruction set computer（RISC） 精简指令系统计算机
pipeline 流水线
operand 操作数
register 寄存器
compiler 编译器,编译程序
branch instruction 转移指令,分支指令
Complex Instruction Set Computer（CISC） 复杂指令系统计算机
superscalar 超级标量
register file 寄存器组,栈
machine cycle 机器周期
microinstruction 微指令
microcode 微代码,微指令
nncroprogram 微程序
addressing 编址,寻址
精简指令系统计算机（RISC）
对高级语言程序执行性能的研究已经为设计新型处理器体系结构－一精简指令系统计算机提供了指南.赋值语句占据的优势表明应对单纯的数据传送进行优化.还有很多IF和LOOP指令存在,需要优化基本的顺序控制机构,以使流水线作业高效率.操作数引用模式的研究表明,在多个寄存器中保存适当数量的操作数,可以提高性能.
这些研究已经形成了RISC机的一些关键特性：（1）有限的固定格式的指令集；（2）使用大量的寄存器或使用编译器优化寄存器应用；（3）重点优化指令流水线.
因为每条指令完成少数的且多为可预测的操作,RISC的简单指令系统适合高效流水线作业.RISC指令系统体系结构也适合于延迟转移技术,在这种技术中,随同其他指令重新安排转移指令以提高流水线效率.
虽然RISC系统已经由不同的（企业）集团以各种方式进行了定义和设计,但大多数设计所提出的关键元素还是共同的.
用大量的通用寄存器（或使用编译器技术）来优化寄存器的使用；
有限的简单指令系统；
重点优化指令流水线作业.
表2-1比较了几种RISC和非RISC系统.
1．指令执行特性
为了解RISC倡导者们的推理思路,首先观察一下指令执行的一些特性.所要关心的计算特性如下所述.
所完成的操作：这些操作决定了处理器要完成的功能和处理器与存储器的交互
所用的操作数：操作数的类型和使用频度决定了存储操作数的存储机制和访问这些操作数的编址方式.
执行顺序：决定了控制和流水线的机制
2．大寄存器组的应用
使用寄存器存储的理由在于它是可用的最快的存储器件,比主存储器和高速缓存都快.寄存器组实际很小,通常与算术逻辑部件和控制器放在同一芯片上,而且使用比高速缓存和内存储器短很多的地址.因而需要一种允许最频繁访问的操作数保存在寄存器中并使寄存器-存储器操作降至最少的策略.
有两种可以采用的基本方法,一种基于软件,一种基于硬件.软件方法靠编译程序最大限度使用寄存器,编译程序力图将给定时间周期内最常用的那些变量分配到这些寄存器中.这一方法要求使用复杂的程序分析算法.硬件方法就是简单地使用更多的寄存器,使更多的变量保存在寄存器中供长时间使用.
3．精简指令系统体系结构的特性
尽管精简指令系统结构的可用方法有多种,但对它们而言有一些特性是共同的.这些特性列在表2-1中,下面进行解释.
表2-1中列出的第一个特性是每个机器周期有一条机器指令.一个机器周期定义为,机器从寄存器组中取出两个操作数,完成一种算术逻辑部件运算并将结果存入一个寄存器中所用的时间.RISC机器指令应该不比CISC机上的微指令复杂,并且执行起来也很快.因为简单,单周期指令仅需少量或不需要微代码；机器指令可以是硬连线的.这样指令执行起来比其他机器的类似机器指令要快,因为在指令执行期间它不必访问微程序控制存储器.
第二个特性是,大多数操作应该是寄存器对寄存器的,仅有简单的取（LOAD）和存（STORE）操作访问存储器.这种设计特点简化了指令系统,因而也简化了控制器.例如,一个RISC指令系统可以只包括一两种加法（ADD）指令〔例如整数加,进位加〕；VAX机则有25种不同的加法指令.另一好处是这种体系结构促进了对寄存器使用的优化,使得频繁访问的操作数保存在高速存储器中.
从表2-1还可看出第三个特性是采用简单的编址方式.几乎所有指令都采用简单的寄存器编址.几种附加的方式,如移位和与PC有关的方式可以包括进去.另外,更为复杂的方式可以用简单的方式在软件中合成.再次强调,这种设计特点简化了指令系统和控制器.
最后一个共同特性是采用简单的指令格式.一般来讲,只使用了一种或少数几种格式.指令长度是固定的并按字的边界调整.字段的位置,特别是操作码的位置是固定的.这种设计有很多优点,使用固定字段,操作码译码和寄存器操作数访问可同时进行.简化的格式简化了控制器；因为是按字长单位来读取的,所以,取指令也得到优化.这也表明一条指令不会跨页.记得采纳啊论文发表、论文指导
周一至周五
9：00&22：00
试析建筑电气中节能方面的设计技术
&&&&&&本期共收录文章20篇
　　摘要：随着时代的发展，建筑中各种电气不断推陈出新，目前，低碳理念已经深入人心，在建筑电气设计中，也需要将节能作为重要的考虑因素，因此，本文对建筑电气进行了节能设计的探究。 中国论文网 /2/view-3533988.htm　　关键词：建筑；电气节能设计；技术分析 　　中图分类号： TU855 文献标识码： A 文章编号： 　　目前，随着我国经济快速发展和城镇化不断推进，建筑电气方面的耗能量非常巨大。人们即要追求建筑室内环境的舒适，又加重了建筑电气耗能的压力。目前很多建筑都实现了智能化，所以在智能建筑的工作中，无论是建筑工作的设计还是具体项目的建设上，都要着重提高能源的使用效率。合理科学的智能化建筑不仅能提高用户的生活舒适度，还可以大幅度地降低能耗。电气是人们日常不可脱离的重要部分，作为智能建筑系统控制的一部分，要实现建筑电气的节能控制，将就必须从多个方面进行考虑和探索。 　　一、灯光节能设计 　　首先，从光源选择上进行优化。在选用光源的时候，根据电光源使用的寿命、调光的性能以及点燃的特征、显色指数多种因素综合进行选择，合理选择高效、节能的光源，这样有利于光源的最优利用。在城市以及农村的一些照明设施上，需要根据实际需求，采用新型节能光源和设备，如采用金卤灯以及电子节能灯、高压钠灯等。 　　其次，从放电光源的启动设备选择上考虑节能因素。通常来说，荧灯光的电感镇流器所消耗的功率是额定功率的百分之二十，而气体的放电灯相应的镇流器则为额定功率的百分之十五左右，因此，跟电感镇流器比较，电子镇流器具有的节能效应更高，同时，电子镇流器在功率消耗上也大大降低，具有显著的节能效果。所以在选择气体放电光源的启动设备的时候，一般可以考虑这种镇流器。 　　再者，选择具有良好节能效应的灯具。随着科技的进步，灯具方面的节能主要体现在能源的高效率运用上。高压钠灯和金卤灯在光效、显色指数以及色温的优越条件下已经取代了传统的高压汞灯。高压钠灯具有110流明每瓦的光效，色温为两百开，显色指数为三十；金卤灯的光效稍低，其色温为五百开，显色指数为六十五。并且钠灯具有较强的透雾性，所以在相同功率条件下，相比于高压钠灯，金卤灯光自身具备的能量会低出百分之四十；在相同的照度要求下，高压钠灯就比金卤灯优越很多了，所以在道路照明设计中首选钠灯。 　　在挑选节能灯具的时候，需要尽量选择高效率的灯具，这样才能达到最佳的节能效果。在我国规范中表明，室内的灯具效率应在百分之五十或者百分之七十以上。在不同类型的灯具当中，效率最高的灯具时直接型的灯具，而效率最低的灯具则是带有保护罩或者是带有格栅的，所以应该尽量选择直接型的。在其它设计用途中，尽量使用控光合理，具有较高光利用系数以及光通量的电气设备，例如空调照明联合的灯具，这样也能节约出能量。 　　除此之外还有光导照明系统的应用。该材料是一种新型照明材料，其采用能够实现对自然光线采集的采光罩，来重新分配自然光线，而导光管由于特殊制作，能够利用其系统下设置的漫射设备，根据实际需要，均匀地分配自然光线，从而创造出独特的照明效果。该系统和以往的照明设备比较，能真正实现节能效应，是一种绿色环保的照明途径。 　　最后，优化照明的设计。优化照明的设计有利于能量的高效利用，如何设计出合理的照明设备，需要从人机学的角度分析，选取出最适合的照度标准，从不同工作面的照度标准中选择不同的照度值，并且根据个人的作业活动范围以及视觉上的舒适性为准，选择最佳照明方式；同时也需要从建筑物的形状以及结构方面入手，加强对自然光的充分利用，采用色调合理的装修，例如白色等可以提高光反射系数，从而达到高对自然光利用率的提高。节能设计还体现在很多地方，例如，在阿尔派思路住宅设计中，在选择采光管的时候，其采用了内部具有镜面材料的采光管，这样可以对自然光进行反射，同时将其引入到绿色智能建筑室内。 　　建筑电气中其他电气节能设计的思考 　　首先，合理降低变压器的损耗。根据能量守恒定律，在电压的转变过程由于自身材料，铁和铜能量的消耗从而产生了各种能量耗损，铁的损耗主要是体现在的漏磁以及涡流耗损上；铜损主要体现在变压器绕组中电阻的大小以及在这些绕组运行时，其遍布的电流量。因此，在选择的时候，应该选择具有节能效果的变压器，这样可以最大程度降低铁损。而为了降低铜损，应该选用具有较小阻值绕组。我们需要选择内部设计较先进的变压器，有利于减少在变压过程的耗损，同时也需要选择容量适当的变压器，这样能减少能源的浪费。 　　其次，优化照明线路设计，减少能量的损耗。从线路上进行优化。根据焦耳定律Q=I^2×Rt，在照明电路中只要有电流通过，就必定会产生一定的耗损，并且在用电期功率恒定的情况下，电压Ｕ不变，电流也是一定的，所以要从电阻R上进行改良，首先：可以采用电阻值相对来说比较小的铜材料，这样从源头上降低了阻值；其次：减少导线的总长度，尽可能选择直线型的线路，这样有利于线长度的减少，同时，线路要直，最大程度减少回头线，以降低由于来回线而产生的电能的损耗；最后，在选择变压器的时候，应该尽量选择跟负荷中心比较靠近的，这样能够大大缩短供电的距离，如果建筑物每一层的面积在一万平方米，则变配电所的数目至少是两个，这样能降低干线总长。对于一些较高的建筑物，在设计低压的配电室时，应该尽量在竖井的地方设置，这样能够防止出现电能从支线向干线倒送的情况发生。 　　从导线的截面设置上进行优化。对于线路较长的，在满足热稳定、流量以及电压损耗等的基本截面设计上，可以增加更高一级的导线截面，这样大大降低了能耗，通常来说，如果导线的截面在七十平方毫米以下，并且线路总长在一百米以上的，设置多一级的导线截面是比较科学的， 　　再者，优化照明系统中功率因素的设计。我们都知道，在建筑照明系统中的大部分用电器中安装的一些零部件是电感元件或热感元件，在工作的过程中会产生很多无用功率，白白浪费了能源，我们可以采用提高设备功率因素的方法来降低其耗损，例如可以采用电子镇流器、补偿电容器、集中电容补偿器等对用电产品进行协助补偿，有利于进一步减少损耗。 　　最后，其他方面设计。第一，科学设计导体的截面积。我们都知道横截面越大它的阻值R就越小，但成本就越高，从长远来看，我们还要考虑它的回收成本，所以在设计的时候要通过计算横截面的最佳面积，这样有利于成本的最优。第二合理选择电动机的功率，从电动机的运行上来省能源，根据需要选择合理荷载的运行效率，减少能源的耗损和浪费，最大程度防止空载、轻载现象的出。第三，优化控制系统设置。在控制系统中可以采用智能的控制方法，例如，可以根据实际需求，由程序来对启动及运行等进行控制，并随时调整负载，也可以通过对水管、风管等末端执行器的调整，来控制其他的动力系统。还能利用可编程的控制器，来进行控制。 　　参考文献： 　　[1]付继铭，建筑电气设计中的节能措施[ J].福建建设科技，-50. 　　[2]GB建筑照明设计标准[S].北京:中国建筑工业出版社, 2004. 　　[3]朱琪. "低碳"与室内居住空间的调和关系——道德设计与审美设计相协调的空间[J].大众文艺，2010, (11) 　　
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谁能给我一份5000词左右的有关建筑方面的英文 有无翻译都可以 表明出处
谁能给我一份5000词左右的有关建筑方面的英文 有无翻译都可以 表明出处
Long before document-shredding became headline news,accountants found themselves under pressure to change.Over the past two decades,innovations in computer technology rendered many of the old-fashioned auditor's functions obsolete,prodding accountants to find other ways to bring in revenue.Companies' desire to produce ever-rosier results for an ever-larger and savvier shareholding public compelled accountants to find ways to put the best possible spin on clients' financial reports.And then there was simple greed.The industry had already shown it was susceptible.In the early 1970s,a prominent accountant was linked to the Watergate scandal.The next decade,the savings-and-loan crisis raised questions about how accountants could have let things get so bad.In recent years,partners' pay,largely determined by hourly billing rates,fell way behind that of accountants' investment-banking brethren,enriched by the rise of the stock-market culture of the '80s and '90s.Hiring consultants and having people sell their services to audit clients was a way to narrow the gap.And ultimately the ancient profession sacrificed the public confidence that underpinned its reputation.The industry was formed as a vessel of trust,originating more than 10,000 years ago with stone counters in Jericho.In ancient Sumerian cities of the land that is now Iraq,bookkeepers documented wealth by pressing the ends of sticks into damp clay tablets that hardened into permanent records.Formal accounting was invented by a Franciscan friar named Luca Pacioli in 1494 in his paper "Summa de Arithmetica,Geometria,Proportioni et Proportionalita" ("Everything About Arithmetic,Geometry and Proportion").The treatise described double-entry bookkeeping -- that for every credit entered into a ledger there must be a debit,a concept created by Florentine merchants and hailed by Goethe as "one of the most beautiful discoveries of the human spirit."Three traits shared by successful merchants,Mr.Pacioli wrote,were access to cash,a constantly updated accounting system and a good bookkeeper.His contemporary Christopher Columbus apparently knew that:On his voyage to the New World,he took a royal accountant to track his "swindle sheet when he started to figure the cost of gold and spices he would accumulate," according to Alistair Cooke's 1973 book "America."The craft changed little until the industrial revolution,when accounting advanced from pure recordkeeping to a means of survival.Josiah Wedgwood,Charles Darwin's grandfather,kept his British pottery factory alive during the depression of 1772 through the innovation of cost accounting -- calculating the costs of materials and labor for each step of the manufacturing process,and then setting prices to ensure enough margin to remain viable.By the mid-19th century,"accompants," as accountants were known,were flourishing in Britain.The Cooper brothers,whose name lives on in PriceWaterhouse Coopers,ran a Dickensian operation of screeching supervisors lording over clerks toiling long hours for scant pay.The industry followed European investments to the New World,and in 1887,31 accountants formed the predecessor to the American Institute of Certified Public Accountants.A decade later,they created a standardized test,bestowing on a man named Frank Broaker the honor of becoming the first CPA.In the early 1930s,after the financial scandals of the '20s and the corporate failures of the Great Depression,the industry sought to formalize consistency,transparency and trust in the profession.Already,in 1922,AICPA had banned its members from advertising,saying it wasn't dignified.The group also forbade accountants to poach each other's clients.The profession got its own governing board and a manual called Generally Accepted Accounting Practices -- GAAP for short.The profession also won the responsibility for auditing public companies,though not without an intense congressional debate.Accountants had become moral guardians -- an image reinforced in the public's imagination in the 1930s,when Price Waterhouse was enlisted by the Academy of Motion Picture Arts and Sciences to count ballots for the Academy Awards.In lieu of the hard sell,accountants networked at the country club and sat on the boards of nonprofit organizations and chambers of commerce.In the 1970s,the federal government,amid questions about some companies' accounting procedures,set up the Financial Accounting Standards Board to oversee accountants.But it soon also removed a lot of the restrictions that had prevented big firms from competing with each other.In the late 1970s,the Federal Trade Commission,concerned about anticompetitive practices,began pushing AICPA to allow accountants to advertise.By 1990,the group had lifted most restrictions on ads.As the 1980s dawned,globalization and deregulation brought new challenges.To raise huge amounts of money,companies turned increasingly away from traditional bank loans and toward more-complex,and often riskier,forms of financing.Executive pay became tied to performance,so clients had a personal stake in making sure their auditors squeezed out the best results they could.And now,in the year 2002,AA has been criminally charged with their document shredding activities.It is anyone鈥檚 guess what is going to happen next.
Long before document-shredding became headline news, accountants found themselves under pressure to change.Over the past two decades, innovations in computer technology rendered many of the old-f...
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