英语硕士论文范文

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篇1

马上就将面临毕业了，大家知道英语硕士论文致谢应该怎么写吗？下面是学术参考网小编为朋友们搜集整理的英语硕士论文致谢，欢迎阅读~希望可以帮助到各位。

Acknowledgements

MydeepestgratitudegoesfirstandforemosttoProfessoraaa，mysupervisor，forherconstantencouragementandguidance.Shehaswalkedmethroughallthestagesofthewritingofthisthesis.Withoutherconsistentandilluminatinginstruction，thisthesiscouldnothavereacheditspresentform.

Second，IwouldliketoexpressmyheartfeltgratitudetoProfessoraaa，wholedmeintotheworldoftranslation.IamalsogreatlyindebtedtotheprofessorsandteachersattheDepartmentofEnglish：Professordddd，Professorssss，whohaveinstructedandhelpedmealotinthepasttwoyears.

Lastmythankswouldgotomybelovedfamilyfortheirlovingconsiderationsandgreatconfidenceinmeallthroughtheseyears.Ialsoowemysinceregratitudetomyfriendsandmyfellowclassmateswhogavemetheirhelpandtimeinlisteningtomeandhelpingmeworkoutmyproblemsduringthedifficultcourseofthethesis

篇2

二十一世纪，随着新课程体系的建立，课程评价体系逐渐引起重视。教学评价包括终结性评价以及形成性评价，在教学中有着重大的作用，不仅可以帮助教师改善教学方法，保证教学质量，而且可以帮助学生调整学习策略，提高学习效率，从而达到以评促学，以评促教的目的。英语视听说课程是英语专业高年级的一门专业选修课，主要是为了培养学生听、说、读、写综合英语能力。在本门课程中，为激发学生练习听说的内在动力，引导学生积极参加课堂活动，提高学生综合运用英语的能力，笔者所在的英语视听说教学组以建构主义理论为主导，注重学生在学习过程中的自主学习，并采用终结性评价和形成性评价相结合的教学评价模式，对学生的学习效果进行科学、合理的评价。 

一、理论基础 

1.形成性评价体系。根据评价在教学过程中的作用和功能，教学评价可以分为形成性评价和终结性评价。传统的终结性评价通常以期末考试、结业考试的形式，在一个阶段的学习结束时对学生学习结果的评价。这虽然在一定程度上可以检验学生的学习成果，但是不利于激发学生的学习兴趣。目前我国仍有许多高校在英语教学中对学生听说能力的评价方式过多地依赖于终结性评价，强化了考试分数的作用，致使相当一部分学生为了考试而专注于考试要求的题目练习，而忽视了实际听说能力的提高，这显然不利于学生自主学习能力的培养。 

相对于传统的终结性评价，形成性评价更注重学生的学习过程。形成性评价是由美国哈弗大学学者斯克里芬（M.Scriven）于1967年率先提出的，后由美国教育学家布鲁姆（B.S.Bloom）应用于教学领域。形成性评价注重观察学生学习过程中的表现、所取得成绩以及其学习态度、学习策略，对学生的学习全过程进行观察、记录、反思以及总结的一种发展性评价体系，有助于激励学生，帮助学生调控自己的学习过程，获得成就感。 

2.建构主义与形成性评价。建构主义也称之为结构主义，是由认知主义发展而来的哲学理念。建构主义理论认为教学是以学生为主体，学生根据自己已有的知识和经验主动建构，创造情境，从而获得知识。同时，建构主义理论认为学生还需要与同伴共同探讨来进行知识建构。由于学生个体差异较大，在同一课程中，不同的学生会采用不同的学习策略，科学公正客观的评价学生的学习结果变得尤为重要。形成性评价，学生是评价的主体，注重对学生在知识建构过程中所采取的学习方法、策略进行评价，从而激励学生、增强学生的学习动力。 

二、评价工具 

英语视听说课程注重语言的人文性，充分利用多媒体教学，将平面教材转化为视频教材，为学习者提供了视觉以及听觉的刺激，创造了一个趣味化的学习环境。结合英语视听说教学特点，笔者所在课程组在教学实践中，对学生的课堂表现以及课外学习采取了终结性评价与形成性评价相结合的评价手段，在形成性评价中主要采取了教师观察、小组协作、电子档案、网络学习等评价手段。 

1.教师观察。教师在形成性评价中扮演非常重要的角色。在形成性评价体系中，教师观察将贯穿整个教学过程，包括正式和非正式两种形式。在日常教学过程中，教师注意观察学生如何使用教材，对教师所教内容的反应，是否积极主动与其他同学合作交流，如何理解运用所学知识。教师以日常行为记录、学生评估表或记事簿等方式记录下来，最后经过汇总，可以将资料反馈给学生，帮助学生了解自己的不足，以便调整学习策略。另外，通过教学活动的观察，教师还可以根据学生的反应了解学生对所学知识的掌握程度，哪一种教学方法更为学生所接受、更为有效以及学生对哪些教学材料更感兴趣。通过教师的观察，教师能够更好地了解学生的学习，根据观察结果教师可以适当调整自己的教学方法。 

2.小组协作。建构主义强调学习者的主体作用。小组协作学习模式是指两个或者多个学生相互配合共同努力来实现学习目标。教师以学习小组为基础，指导小组成员相互学习，相互合作，发挥群体的积极性，提高个体的学习效率，从而激发学生的积极性和创造性。在英语视听说课堂上，课程组尝试在影视剧作品模仿改编中根据学生的学习兴趣、学习成绩、性别比例、交往技能等，将学生分成若干学习小组。每个小组的整体英语水平相当。学生以小组形式，进行角色分配，对经典影视剧中的片段进行模仿改编，并提交一份书面材料总结小组合作的成员分工、取得结果、存在的问题以及改进方式。另外每一小组都要对其他小组进行评价打分，并计入平时成绩。小组合作不仅让学生更加积极主动地融入课堂，还可以让学生取长补短、培养团队合作意识。　在形成性评价中，教师不再成为评价的唯一主体，学生也可以参与到评价中来。这一方面调动了学生的学习积极性，使学生更主动的参与到学习中，同时也保证了评价的公正性和客观性。但是在实际的评价中，教师应进行指导和监督，同时教师评价和学生评价所占的比例也应当结合具体的课程做出设计，以保证评价的科学性。 

3.电子档案。电子档案，又称之为成长记录袋，是关于学生学习成绩以及学生发展状况的汇集，在形成性评价中是一个非常重要的手段。动态性是电子档案袋的一个显著特征，随着每天、每周、以及每月而不断发生改变。通过电子档案，教师可以记录、存储、再现学生的学习过程并评价学习过程以及学习成果。另外，在教学过程中，教师可以建立教师电子档案袋记录日常教务活动，对学生的成绩进行管理，进行学期评定、反馈指导。档案袋真实反映了学生的成绩，更有助于教师了解学生。定期对学生电子档案的分析可以帮助教师发现教学中的不足，调整教学策略。同时，电子档案也更有助于学生交流学习，学生可以经常回顾自己以及他人的电子档案，借鉴其他同学的经验，不断提高自己。 

篇3

    Fan Zhang

    University of Limerick

    MEng. Computer and Communication Systems

    ID: 0526401

    Abstract: I am a video game fan, but not an addict. Since this topic attracted me a lot, I decided to choose this one as my topic for the third assignment of Processor Architecture Module. I started to play video games since I was five. While I was playing games, I found the game console itself just like a mystery, how could they react our actions to the controller then reflects so amazing pictures on TV? Although I have read a lot about it in game magazines, I admit that I didn’t try to find the answer until I found this topic. This is a great chance for me to answer the question myself. At the same time, I want to present you this paper, which should be fun.

    This paper concerns the differences of architecture between PC and PlayStation 2. Since the purposes of PC and PlayStation 2 are different (or maybe I should say the purposes of PC include that of PlayStation 2), the different objectives decide the different design orientation. I think PlayStation 2 is a good game console for the comparison. First, a lot of documentations about PlayStation 2’s Emotion Engine can be found in the Internet. Second, as far as I know, PlayStation 2’s design has straightforward purposes: 3D games and multimedia, which makes the game console is seemed to be born for these two reasons. Contrasts to PlayStation, current PCs do very well on these two aspects, but the cost is the unstoppable upgrade of hardware. PlayStation 2 is a product born 5 years ago. Today tens of millions of people are still enjoy PlayStation games at home. 5-year-old PCs have been washed out already.

    Keywords: PC, processor, video card, system controller, bus, Emotion Engine, Vector Unit, Graphics Synthesize.

    1. INTRODUCTION

    1.1 The evolution of game performance

    The computer technology has achieved rapid evolution this year. From Figure 1.1 to Figure 1.5 you can see, in almost twenty years, how great changes of game performance are, both PC and game consoles.

    Figure 1.1: Final Fantasy I (FC) 1987 by SQUARE

    Figure 1.2: Final Fantasy XII (PlayStation 2) 2006 by SQUARE ENIX

    Figure 1.3: Prince of Persia (PC) 1989 by Broderbund

    Figure 1.4 Prince of Persia: The Two Thrones (PC) 2006 by Ubisoft

    The screenshots above are the evidences of technique developments. In these twenty years, computers are almost 10 times faster than in the 1980’s. The cost of buying a computer is decreasing simultaneously. However, the development orientations of both PC and game consoles didn’t change much during these 20 years. Here I want to say game consoles and PC are different, although they both can be classified to ‘computer’ class, although PC includes all game consoles’ functions (but the software are not compatible each other). The differences include many areas, the architecture, the media, the software producing and selling model, and the customers.

    1.2 Why they are different?

    I would rather to say it is because of the distinct purposes. Of course PC can play games, can do anything that game consoles do, and in the present, PlayStation 2, the most famous game console in the world, can connect to Internet, can print paper, even can run complete Linux operating system, but PC is general purpose, this means PC should care too much things, and be good at almost everything. For instance, PC should be good at text processing, games, printing, Internet connection, a huge amount of protocols are settled for it; PC also need to compatible with all components and software that are designed and implemented by current standards. But game consoles are different. They need only care about games, which mean most designs are flexible. At the same time, the standards which PC has to obey do not affect it at all. No extra cost, no burden, only focus on games.

    Figure 1.5: Sony’s PlayStation 2

    1.3 Multimedia

    From later 20th century, multimedia has become one of the main purposes of PC. Corresponding new technology for enhancing the capability of multimedia processing on PC has been developed as well. However, the reality of transmission speed bottleneck hasn’t been changed much. Keith Diefendorff and Pradeep K. Dubey published an article named “How Multimedia workloads will change Processor Design” in 1996. They argued the dynamic media processing would be a big challenge for current processor architecture. They also thought it will force the fundamental changes in processor design.

    Before Pentium 4, the processors shared the same character: their data cache memory was big, but instruction cache memory was relatively small. It was quite useful for most usage, for instance, word editor, e-business, stock information processing, and so on. However, Diefendorff did not think it is useful, or efficient enough for multimedia processing, for multimedia data come and forth constantly, no need to settle a huge bulk of storage space for holding the information that rarely has chance of reuse. Contrarily, multimedia processing requires more calculation than others. So, for multimedia calculation, the instruction cache memory should become larger, both caches require faster transmission speed as well. We shall see this prediction has realized much in both Pentium 4 and PlayStation 2.

    1.4 The purpose and the brief layout of the article

    This paper is mainly talk about the architectural differences between PC and PlayStation 2, which is the most famous game console in the world. The article will discuss several aspects, the whole architecture, the CPU, the motherboard, and the graphics. In the following section, the whole architectures are compared. Two processors, Intel’s Pentium 4 and PlayStation 2’s Emotion Engine are discussed and compared in the third section. The fourth section is about the bus and caching comparison. The fifth section mainly talks about PC and PlayStation 2’s graphic devices, Video card and Graphics Synthesizer. The conclusion will be made in the last section.

    2. WHOLE ARCHITECTURE COMPARISON

    2.1 PC architecture

    The basis of PC could root back to 1940’s. John von Neumann (1903-57), who constructed a very basis structure of computer, stayed his name in the history forever. The architecture of modern PC is still based mainly on his architecture. Let’s see a diagram of PC architecture as our basis of illustrating how PC works for game performance in the future.

    Figure 2.1: PC architecture--------------------------------->

    Different regions in the diagram have different clock speed. We can see the system controller is the heart of whole PC system. It carries data between processor and other components in PC over bridge. The bridge is used to connect interfaces and buses. Two kinds of bridges exist in PC, North Bridge (the system controller) and south bridge (the bus bridge). The system controller provides an interface between the processor and external devices, both memory and I/O. The system controller works with the processor to perform bus cycles.

    From the diagram we can see, the system controller makes the whole diagram to be complicated. This is because the system controller has to adjust the bus cycles between the processor and the external device that it wants to access. Briefly, the PC’s working procedure can be described as follow:

    PC executes commandsèaccess data with the help of system controllerèreturns the execution resultèexecute commandsè…

    System controller also possesses the function of controlling DMA (Direct Memory Access), which is the ability to transfer data between memory and I/O without processor intervention.

    2.2 PlayStation 2 Overview

    Let’s first see the architecture of PlayStation 2.

    Figure 2.2: the architecture of PlayStation 2---------------->

    PlayStation 2 is composed of a graphics synthesizer, the Emotion Engine, the I/O Processor (IOP), and a Sound Processor Unit (SPU). The IOP controls peripheral devices such as controller and disk drive and detect controller input, which is sent to the Emotional Engine. According to this signal, the Emotional Engine updates the internal virtual world of the game program within the video frame rate. Many physical equations need to be solved to determine the behavior of the character in the game world. After this is determined, the calculated object position is transformed according to the viewpoint, and a drawing command sequence (display list) is generated. When the graphics synthesizer receives the display list, it draws the primitive shape based on connected triangles on the frame buffer. The contents of the frame buffer are then converted from digital to analogue, and the video image appears on the TV. Finally, the Sound Processor is in charge of sound card thing, it outputs 3D digital sound using AC-3 and DTS. This is the overview of PlayStation 2 working procedure.

    2.3 Comparison

    Compare Figure 2.1 and Figure 2.2, we can see that the PC’s architecture is far more complex than that of PlayStation 2’s. There are many reasons. PC has more devices has to care. For instance, PlayStation’s I/O processor, which is act as the same role as the system controller bus in PC, the chief responsibility of this chip is to manage the different devices attached to the PS2. 2 PlayStation controller port, and MagicGate-compatible memory card interface, 2 USB ports, and a full-speed 400Mbps IEEE 1394 port, which are much less than PC. The other main reason is processor’s speed increased much faster than other devices; the devices themselves had uneven speed increments as well. In general, PlayStation 2 has simpler architecture and less components and devices.

    3. ALL ABOUT PROCESSORS

    3.1 Pentium 4 Processor

    Pentium 4 adopts Intel’s 7th generation architecture. We can see in detail from the diagram below. Since the birthday of PlayStation 2 waiting for exploring was 4th March 2000, when Pentium 4 was not published yet. It is unfair to PlayStation 2. However, Pentium 4 is the most popular processor in the present, and PlayStation 2 is globally the most popular game console, whatever.

    Figure 3.1: Pentium 4 processor architecture

    Since the previous generation architecture (Pentium III) Intel began to use hybrid CISC/RISC architecture. The processor has to accept CISC instructions, because it has to be compatible with all current software (most software is written using CISC instructions). However, Pentium 4 processes RISC-like instructions, but its front-end accepts only CISC x86 instructions. A decoder is in charge of the translation. Intel doesn’t create the path for programs using pure RISC instructions.

    CISC instructions are rather complex, decoding one may cost several clock cycles. In Pentium III era, once a CISC instruction needed to be processed several times (i.e. a small loop), the decoder had to decode the instruction again and again. In Pentium 4 this situation has been improved by replacing Pentium III’s L1 instruction cache to Trace Cache, which is placed behind the decoder. The trace cache ensures that the processor pipeline is continuously fed with instructions, decoupling the execution path from a possible stall-threat of the decoder units. After decoding stage, Intel introduces the Renamer/Allocator unit to change the name and contents of 32-bit CISC instructions of the registers used by the program into one of the 128 internal registers available, allowing the instruction to run at the same time of another instruction that uses the exact same standard register, or even out-of-order, i.e. this allows the second instruction to run before the first instruction even if they mess with the same register.

    The other big advance of Pentium 4 is its SSE2 - The New Double Precision Streaming SIMD Extensions. 128-bit SIMD package offers 144 strong instructions. Intel prepares two SIMD instruction units for Pentium 4 (64-bit each), one for instructions, and the other for data. Let’s recall Section 1.3, Pentium 4’s 128-bit SIMD extension is Intel’s efforts for meeting the future requirements for multimedia implementations. Because of that, video, games implementation capability gained the drastic enforcement.

    Pentium 4’s pipeline is the most disputable place. When it was announced, 20-stage pipeline surprised a lot of people. Intel did so because the more stage pipeline can increase the clock rate of processor. However, once the pipeline does not contain the information what processor need, the pipeline refill-time is going to be a long wait. In fact, Pentium 4 is only faster than Pentium III because it works at a higher clock rate. Under the same clock rate, a Pentium III CPU would be faster than a Pentium 4.

    Figure 3.2: Pentium 4 Pipeline

    The scheduler is a heart of out-of-order engine in Pentium 4. It organizes and dispatches all microinstructions (in other words, uops) into specialized order for execution engines.

    Figure 3.3: Pentium 4 scheduler

    Four kinds of schedulers deal with different kinds of microinstructions for keeping the processor busy all the time. The ports are Pentium 4’s dispatch ports. If you read the diagram carefully, you can see Port 1 and Port 0 each is assigned a floating-point microinstruction, Port 0 is assigned Simple FP Scheduler (contains simple Floating-point microinstructions) and Port 1 is assigned Slow / Floating Point Scheduler (contains complex floating-point microinstructions). Port 0 and Port 1 also accept the microinstructions came from Fast Scheduler. For the floating point microinstruction may run several clock cycles, Pentium 4’s scheduler monitor decides to transfer the microinstruction to Port 1 if Port 0 is busy, and vice versa. Port 2 is in charge of Load microinstructions and Port 3 deals with Store microinstructions.

    3.2 PlayStation 2’s Emotion Engine

    PlayStation 2’s designers focus deeply on the purpose of 3D games. At the same time, they had to ensure it was completely compatible with DVD video. For performing 3D games well, PlayStation 2 has to possess perfect vision and audio functions. Emotion Engine acts as the role of Geometry calculator (transforms, translations, etc), Behavior/World simulator (enemy AI, calculating the friction between two objects, calculating the height of a wave on a pond, etc). It also in charge of a secondary job of Misc. functions (program control, housekeeping, etc). In general, Emotion Engine is the combination of CPU and DSP processor.

    Figure 3.4: The architecture of Emotion Engine

    The basic architecture of Emotion Engine is show in Figure 14. The units are composed of

    (1) MIPS III CPU core

    (2) Vector Unit (two vector units, VU0 and VU1)

    (3) Floating-Point Coprocessor (FPU)

    (4) Image Processing Unit (IPU)

    (5) 10-channel DMA controller

    (6) Graphics Interface Unit (GIF)

    (7) RDRAM interface and I/O interface.

    Something interesting in the diagram you may have noticed. First, inside the Emotion Engine, there is a main bus connects all components for data communication. However, between MIP III core and FPU, VU0 and MIP III, VU1 and GIF, there are dedicate 128-bit buses connect them. Second, VU0 and VU1 have certain relationship shown in the diagram. This design extremely enhanced the flexibility of programming with Emotion Engine.

    MIPS III Core connects with the FPU and VU0 directly with the dedicated buses. The pipeline of MIPS III is 6-stage. The MIPS III is the primary and controlling part, VU0 and the FPU are coprocessors to MIPS III. They compute the behavior and emotion of synthesis, physical calculations, etc For example, in a football game, the flying orbits of the ball, the wind effect, the friction between ball and the ground need to be calculated. At the same time, 21 player’s AI needs to be implemented (the last player is controlled by the user), the activity, the lineup, etc. After the calculation, MIPS III core sends out the display list to GIF.

    VU1 has a dedicated 128-bit bus connected to GIF, which is the interface between GS (Graphics Synthesizer) and EE (Emotion Engine). VU1 can independently generate display list and send to GIF via its dedicated bus. Both of these relationships forms a kind of dedicate and flexible structure. The final goal of EE is generating display list and send to GS. The programmer can choose either programming two groups (MIPSIII + FPU + VU0 and VU1 + GIF) separately, send their display list in parallel, or programming purposely, making MIPS III + FPU + VU0 group as the “coprocessor” of VU1, for instance, generate physical and AI information then send to VU1, VU1 then produces corresponding display list. The diagram below shows the two programming methods.

    (a)                                                       (b)

    Figure 3.5: Two programming methods of Emotion Engine

    MIPS ISA is an industry standard RISC ISA that found in applications almost everywhere. Sony’s MIPS III implementation is a 2-issue design that supports multimedia instruction set enhancements. It has

    (1) 32, 128-bit general purpose registers

    (2) 2, 64-bit integer ALUs

    (3) 1 Branch Execution Unit

    (4) 1 FPU coprocessor (COP1)

    (5) 1 vector coprocessor (COP2)

    What I really want to cover are two vector processors, VU0 and VU1. This is the main reason why PlayStation 2 is powerful.

    VU0 is a 128-bit SIMD/VLIW design. The main job of VU0 is acting as the coprocessor of MIPS III. It is a powerful Floating-point co-processor; deal with the complex computation of emotion synthesis and physical calculation.

    The instruction set of VU0 is just 32-bit MIPS COP instructions. But it is mixed with integer, FPU, and branch instructions. VIF is in charge of unpacking the floating-point data in the main bus to 4 * 32 words (w, x, y, z) for processing by FMAC. VU0 also possesses 32 128-bit floating-point registers and 16 16-bit integers.

    VU0 is pretty strong. It is equipped with 4 FMACs, 1 FDIV, 1 LSU, 1 ALU and 1 random number generator. FMAC can do the Floating-Point Multiply Accumulate calculation and Minimum / Maximum in 1 cycle; FDIV can do the Floating-Point Divide in 7 cycles, Square Root in 7 cycles, and Inverse Square Root in 13 cycles. In fact, as the coprocessor of MIPS III, VU0 only uses its four FMACs. However, VU0 doesn’t have to stay in coprocessor mode all the time. It can operate in VLIW mode (as a MIPS III coprocessor, VU0 only takes 32-bit instructions. In VILW mode, the instruction can be extended to 64-bit long). By calling a micro-subroutine of VLIW code. In this case, it splits the 64-bit instruction it takes into two 32-bit MIPS COP2 instructions, and executes them in parallel, just like VU1.

    VU1 has very similar architecture than VU0. The diagram below is the architecture of VU1 possesses all function that VU0 has, plus some enhancement. First, VU1 is a fully independent SIMD/VLIW processor and deal with geometry processing. Second, VU1 has stronger capability than VU0: it has a 16K bytes’ instruction memory and a 16K bytes’ data memory, which VU0 only has 4K bytes each. VU1 acts as the role of geometry processor; it burdens more instructions and data to be computed. Third, VU1 has three different paths to lead its way to GIF. It can transmit the display list from 128-bit main bus, just as VU0 + CPU + FPU do; or it can transmit via the direct 128-bit bus between its VIF and GIF; the last one is quite interesting, the path comes out from the lower execution unit (which I will talk about later) and goes directly to GIF. Three individual paths ensure two main problems of PC 3D game programming will not happen: first, the bottleneck of bus bandwidth; second, the simplex way of programming.

    Figure 3.6: The architecture of VU1

    VU1’s VIF does much more than that of VU0 does. The VIF takes and parses in which Sony called 3D display list. The 3D display list constructs of two types of data: the VU1 programming instructions (which goes to Instruction memory) and the data that the instruction deal with (which goes to Data memory). The instruction itself can be divided into two units, Upper instruction and Lower Instruction, which directly operate on two different execution units, Upper execution unit and Lower execution unit. The 64-bit VLIW instruction can be used to deal with two operations in parallel. Recall that VU0 possesses the same function but most of time it acts only as the coprocessor of MIPS III, this mode can only operate 32-bit SIMD instructions. Programmers also rarely ask VU0 to do the same thing what VU1 is good at.

    3.3 Comparison

    I strongly agree if you think Emotion Engine is more flexible than Pentium 4. The design of Emotion Engine is completely around the performance of 3D games. Two vector units, VU0 and VU1, contribute a lot for the game performance. Pentium 4 architecture is straight, you can trace the path of data from the very beginning, and soon you will be able to know how Pentium 4 works easily. For Emotion Engine, except you are the game designer, you will never know exactly.

    I did not put too much digits in this section, the comparison of digits does not make sense at all. The comparison between two PC processors depends on digits, because they are the same kind and work in the same situation. For game consoles, without the burden of compatibility, the designers think a lot for the perfect cooperation. This would results in better performance, plus less cost. Unfortunately the programmers don’t think it is a good idea, it cost them quite a lot of time to investigate the processor to figure how it works.

    4. BUSES AND CACHEING

    4.1 PC Motherboard

    While multimedia processing requires massive quantities of data to move rapidly throughout the system, the speed difference between processor and external devices is the main bottleneck of PC. Processor companies like Intel have put a lot of energy into getting the rest of the system components to run faster, even if other vendors provide these components. Improving the performance of motherboard is a good idea. Figure 4.1 is the main structure diagram of GIGABYTE GA-8TRX330-L Pentium 4 Motherboard. The bandwidth between Processor and system controller, main memory and system controller has reached to equally incredible 6.4GB/S. However, the latency of memory is still impossible to remove. Here I want to talk something about the processor caching mechanism.

    In the present, motherboard’s FSB (Front Side Bus) frequency has over 800 megahertz. However, it is slower than that of Pentium 4, which is over 3 gigahertz. Processor runs at a multiple of the motherboard clock speed, and is closely coupled to a local SRAM cache (L1 cache). If processor requires data it will fist look at L1 cache. If it is in L1 cache, the processor read the data at a high speed and no need to do the further search. If it is not, sadly processor has to slow down to the motherboard clock speed (what a drastic brake!) and contact to system controller. System controller will check if L2 cache has the required data. If has, the data is passed to processor. If not, processor has to access the DRAM, which is a relatively slow transfer.

    4.2 About PlayStation 2’s buses and caching.

    Recall Figure 2.2, we can see 32-bit interfaces between processor and I/O Processor, main memory and I/O Processor, which can achieve 3.2GB/S bus speed. Although slower than Pentium 4, Emotion Engine itself is relatively slow as well, 300MHz MIPS III processor. However, PlayStation 2’s 32-bit interface, 10-channel DMAC, 128-bit internal bus, and small cache memory group to an incredible caching condition. Any data necessary can be store or download in time. This strategy takes 90% of DMA capability. It makes the latency which main memory generates is acceptable for Emotion Engine.

    4.3 Comparison

    This time we can talk about digits some more. Let’s see a Pentium 4’s cache memory

    L1 trace cache: 150K

    L1 data memory: 16K

    L2 memory: 256K ~ 2MB total: 422~2204K

    Let’s see PlayStation 2 next

    VU0 data memory: 4K

    VU0 instruction memory 4K

    VU1 data memory 16K

    VU1 instruction memory 16K

    MIPS III data memory: 2-way 8K

    MIPS III instruction memory: 2-way 16K total: 64K

    Contrast to Pentium 4, the cache memory of PlayStation 2 is too small. Its capability is indeed ‘weak’ in the present. Pentium 4 is able to hold more data and does more computations in parallel. However, PC architecture hasn’t been improved along with the processor. No matter how Pentium 4 fast is, present bus architecture is never going to perform Pentium 4 100% capability. PlayStation 2 achieves a nearly perfect structure and mechanism, which helps it exert as much as it can (or maybe I should say because Pentium 4 is too fast, the memory speed is relatively too slow). Besides, it remarkably low down the cost, you can afford a PlayStation 2 plus a controller with the same price of a single Pentium 4 chip.

    5. VIDEO PERFORMANCE

    5.1 Comparison of performance between PC and PlayStation 2

    Figure 5.1 Need for Speed Most Wanted (PlayStation 2) 2006 by EA GAMES

    PlayStation 2 Graphics Synthesizer (GS)

    · 150 MHz (147.456 MHz)

    · 16 Pixel Pipelines

    · 2.4 Gigapixels per Second (no texture)

    · 1.2 Gigatexels per Second

    · Point, Bilinear, Trilinear, Anisotropic Mip-Map Filtering

    · Perspective-Correct Texture Mapping

    · Bump Mapping

    · Environment Mapping

    · 32-bit Color (RGBA)

    · 32-bit Z Buffer

    · 4MB Multiported Embedded DRAM

    · 38.4 Gigabytes per Second eDRAM Bandwidth (19.2 GB/s in each direction)

    · 9.6 Gigabytes per Second eDRAM Texture Bandwidth

    · 150 Million Particles per Second

    · Polygon Drawing Rate:

    · 75 Million Polygons per Second (small polygon)

    · 50 Million Polygons per Second (48-pixel quad with Z and Alpha)

    · 30 Million Polygons per Second (50-pixel triangle with Z and Alpha)

    · 25 Million Polygons per Second (48-pixel quad with Z, Alpha, and Texture)

    · 18.75 Million Sprites per Second (8 x 8 pixel sprites)

    Figure 5.2 Needs for Speed Most Wanted (PC) 2006 by EA GAMES

    PC Graphics Chip RADEON X300 SE PCI Express

    · Bus type PCI Express (x16 lanes)

    · Maximum vertical refresh rate 85 Hz

    · Display support Integrated 400 MHz RAMDAC

    · Display max resolution 2048 x 1536

    · Board configuration

    · 64 MB frame buffer

    · Graphics Chip RADEON X300 SE PCI Express

    · Core clock 325 MHz

    · Memory clock 200 MHz

    · Frame buffer 64 MB DDR

    · Memory I/O 64 bit

    · Memory Configuration 4 pieces 8Mx16 DDR

    · Board configuration

    · 128 MB frame buffer

    · Specification Description

    · Graphics Chip RADEON X300 SE PCI Express

    · Core clock 325 MHz

    · Memory clock 200 MHz

    · Frame buffer 128 MB DDR

    · Memory I/O 64 bit

    · Memory Configuration 4 pieces 16M x 16 DDR

    · Memory type DDR1

    · Memory 128 MB

    · Operating systems support Windows? 2000, Windows XP, Linux XFree86 and X.Org.

    · Core power 16 W (Max board power)

    From the data we can see. GS is too weak, contrast to low-level video card of PC. However, the performance of PlayStation is not too that bad. I don’t want to analyze data here. What I am interested to discuss is about the performance itself.

    Let’s see Figure 5.2 in detail. Texture is very clear and exquisite. This is what big video memory offers. The tree leaves in distance need a lot of polygons to build. The video card itself is low-level; possess no special effect for the game rendering. No refection and other sparking place can be found. In general, the game performance is only ok.

    Figure 5.3 PC game rendering related architecture

    Now let’s see PlayStation 2’s performance, which is in Figure 5.1. We see a good image. If you look the image in detail, you may found the mountain beside the road is weird: the shape of mountain is not that nature, like some spectrum graphics. This is done by VU1, which draws the Bezile, build 3D graphic based on the curve. Although not good enough, how many people will actually notice that when dashing at over 200km/h with his virtual car? VU1 does a lot of job like that and it could generate a lot of shapes without too many polygons to build. Now let’s see the car, the refection of cars is true reflection (which means it is not fake texture pretended to be the reflection), we can distinguish the mountains behind, however very blur. The whole image is not as clear as Figure 5.2 because the limitation of GS’s video memory (4M). However, this image is good enough for most PlayStation 2 players.

    5.2 Some more about the video performance

    Although Pentium 4 has enough capability to process image real time, the way of implementing games is still no change. The video card read the content of texture into its local memory card, the processor only deal with the data and instructions. After the calculation, the processor stores the display list (a list, recorded with the details of all elements, for instance, one single polygon’s position and texture code) back to the main memory. Video card then access the lists and process them, generate picture, transfer to analogue signal and output. Most special effects depend on the video card. So, no good card, no good performance.

    Let’s see figure 2.2, we will see there is no direct connection between GS and main memory. At the PC’s point of view, 4MB video-memory is not enough to show a single frame with 1024*768 pixels. How is PlayStation 2 able to perform like that? The answer is bus. So we come back to section 4 again. The specialized display list (which Sony called 3D display list) is directly sent to GS, along with the required texture. GS has a huge bandwidth (3.8GB/S), its local memory can work as fast as it is (maybe it is more suitable if we call the memory as cache). GS itself supports only a few special effects. However, this situation can be improved by the simulation calculations finished by Emotion Engine… Again, PlayStation 2’s elegant design makes its all components work as a whole.

    6. CONCLUSION

    Hopefully you have got the idea of how PlayStation 2 and PC architecture differ. Let’s go through it again.

    General architecture. PCs are more complex to read, but easier to implement. The system bus directly manages all devices inter-communications. PlayStation 2’s is easy to read, but much harder to implement. The communication between each other is convenient.

    Processor architecture. The trend of processor architecture design is meeting the requirement of multimedia. Both PC’s Pentium 4 and PlayStation 2’s Emotion Engine are qualified to run multimedia applications efficiently. Pentium 4 is much stronger than Emotion Engine, but the architecture is very ‘straight’ and has to do extra jobs of translating instructions to be compatible with current applications. Emotion Engine has no this burden, the specialized 3D game performance design make it easy to handle complex calculation jobs with relatively low clock rate.

    Buses and Caching. PC has classic bottlenecks and there is no way to overcome it. Current PC buses and cache has improved a lot by increasing the bandwidth and cache volumes, but the latency of main memory cannot be solved. PlayStation 2 works on nearly full load; perfect coordination between components is almost achieved.

    Video. Although Pentium 4 can run perfectly on multimedia applications, the PC game developers don’t think so. They still stick to push the texture and other data into the video memory for one time. The awkward situation is, when you want to update your PC for high requirement games, the first component came into your mind must be the video card but processor. It is impossible to ask PlayStation 2 players to update. Emotion Engine is in charge of many jobs what PC’s video card does. The good condition of data transmission makes it is possible to implement ‘true’ multimedia processing in games, that is treating game image as media streams, no need to supply huge data storage to hold that.

    Purpose: PC’s general—purpose VS PlayStation 2’s 3D game rendering purpose.

    PlayStation 2 is 6 years old now. According to the principle of game console life expectance, it is time to hand the baton to its offspring, PlayStation 3. It is a successful game console of Sony. Contrast to PC, it is too weird, but all its weird compositions seemed so reasonable as well. PC’s architecture is classical; all components have its space for upgrade. Maybe it is too early to say the architecture should evolve. However, PlayStation 2’s architecture gave us a good lesson. If you only were interested in games, you should buy a PlayStation series, not a PC. At least, you need not worry about upgrading your components for the next game. Special architecture can make it becomes the best in specialized region.

    7. REFERENCE

    [1] William Buchanan and Austin Wilson, “Advanced PC Architecture”, ISBN: 0 201 39858 3

    [2] John L. Hennessy and David A. Patterson, “Computer Architecture—A Quantitative Approach”, ISBN: 1 55890 724 2

    [3] Keith Diefendorff and Pradeep K. Dubey, "How Multimedia Workloads Will Change Processor Design." Computer, September 1997

    [4] Jon "Hannibal" Stokes Sound and Vision: A Technical Overview of the Emotion Engine Wednesday, February 16, 2000

    [5] K. Kutaragi et al "A Micro Processor with a 128b CPU, 10 Floating-Point MACs, 4 Floating-Point Dividers, and an MPEG2 Decoder," ISSCC (Int’l Solid-State Circuits Conf.) Digest of Tech. Papers,Feb. 1999, pp. 256-257.

    [6] Jon "Hannibal" Stokes “SIMD architectures”

    arstechnica.com/articles/paedia/cpu/simd.ars

    [7] “Graphics Synthesizer – Features and General Specifications”

    arstechnica.com/cpu/1q99/playstation2-gfx.html

    [8] “The Technology behind PlayStation 2”

    ieee.org.uk/docs/sony.pdf

    [9] Michael Karbo,“PC Architecture“

    karbosguide.com/books/pcarchitecture/start.htm

    [10] Gabriel Torres, “Inside Pentium 4 Architecture”

    hardwaresecrets.com/article/235/1

    [11] Thomas Pabst, “Intel’s new Pentium 4 Architecture”

    tomshardware.co.uk/2000/11/20/intel/

    [12] KuaiLeDaYuShu, “Video Card Parameters Analysis”

    blog.yesky.com/Blog/joyelm/archive/2005/07/30/253803.html

    [13]Howstuffworks “How PlayStation 2 Works”

    entertainment.howstuffworks.com/ps21.htm

篇4

1.什么是注册入学。注册入学与统一招生录取相比，江苏省试行的注册入学是高校招生的一种新的模式。与传统的统一招生录取相比，注册入学要相对简单的多，院校根据学生的高考成绩、学业水平、测评等来进行录取，学生只要符合院校条件，很容易被申请的院校录取，这种不再单一的根据学生成绩录取的方式给了学生更多的选择，让学生可以简便入学。

2.注册入学背景下学生英语能力分析。注册入学实行七年以来，招生的学生越来越多，根据近年来学生状况可以分析出选择注册入学的学生有以下三类：一是学生高考成绩不理想的，一考定终身的弊端让他们没有达到上本科或是重点高职院校，只能选择注册入学；二是学生本事成绩就差，上不起民办的，就选择注册入学；三是填志愿滑档的，无奈选择注册入学。这就带来问题，学生学习成绩良莠不齐，在我国，英语一直是我国大多学生的学习短板，在注册入学的学生中大多数英语基础薄弱，而又有部分学生英语素质高，这就给高职公共英语教学带来很多的挑战。

二、注册入学背景下学生对于英语需求层次分析

1.注册入学下公共英语教学现状。在注册入学背景下，现在高职院校的公共英语教学还采取以往的唯教材论，教学内容空洞、教学手段单一、学生主动性差，这些都使原有的教学模式不再适应现今的教学。对于高职公共英语改革的呼声一直都高，但是应该怎么做，却一直没有定论。

2.学生需求层次的分析。（1）学生需求变化。随着社会变迁，现在学生需求也在发生变化，在以为的教学中，学生因继续深造、工作需求等对英语的重视程度也在发生改变。随着社会就业压力的加大，选择继续深造的人越来越多了，其中英语所占比重并未减轻，就考研情况说，每年考研初试未通过的一半以上是因为英语成绩没达到要求，这些都受注册入学的影响，在一个班级里，老师不能过分迁就成绩差的，也不能迎合成绩好的，而中等成绩的学生也没有从中受益。（2）社会需求变化。现今社会的公司对员工的英语需求存在两极化的区别，在一些大型企业和英语对口单位对英语的要求有增无减，而一些中小企业几乎对英语不做任何要求，这也给教学提供了更多的挑战，如何让非英语专业的学生通过公共英语能在竞争中获胜，这给授课教师提出了更多的要求。

三、高职英语的改革历程

1.教材版本过于呆板，很多知识陈旧，框架也过于刻板，现在使用的教材很多年都没有变动，有的甚至是十年前的编订的，根本不适合现在社会英语的发展，有的教材想突破这种现状，尝试开辟新的模块，所谓的拓展训练、新式阅读、课时训练，其实只是换汤不换药，反而加大了学生的课业压力。关于教材的选定，要征求授课教师的意见，改变教材采购的利益链。

2.现有知道思想过于强调基础知识的学习，对于高职院校而言，学生主要任务就是要通过英语三级半的考试，至于学生英语以后的发展就不在学校的计划内，公共英语也就完成了它的任务。

3.注册入学下，学生人数剧增，师资力量存在一定的断档，一般老师一节公共英语要几个班级一起上，很难顾及到每个同学，就只是按照大纲要求进行授课。甚至有的是在校的研究生。

四、分层教学的理论分析

1.什么是分层教学。分层教学就是教师根据学生现有的知识、能力水平和潜力倾向把学生科学地分成几组各自水平相近的群体并区别对待，采用因材施教的方法，最大限度的用适合学生的方法进行教学，最大程度满足学生需求。

2.分层教学的理论依据。分层教学理论最早来源于孔子的因材施教，用适合学生的教材去教育学生，在现代教学中是一项重要的教学方法和教学原则，要求在教学中根据学生的认知水平、学习能力及自身素质来安排教学，这种针对每个学生特点采取的特殊教学方法对学生的发展有很大的积极作用。在公共英语教学中引入分层教学是为了解决注册入学背景下英语中存在的问题，根据学生英语水平和兴趣倾向，能动的讲学生分组。