模糊控制理论
概述
模糊逻辑广泛适用于机械控制。这个词本身激发一个一定的怀疑,试探相当于“仓促的逻辑”或“虚假的逻辑”,但“模糊”不是指一个部分缺乏严格性的方法,而这样的事实,即逻辑涉及能处理的概念,不能被表达为“对”或“否”,而是因为“部分真实”。虽然遗传算法和神经网络可以执行一样模糊逻辑在很多情况下,模糊逻辑的优点是解决这个问题的方法,能够被铸造方面接线员能了解,以便他们的经验,可用于设计的控制器。这让它更容易完成机械化已成功由人执行。
历史以及应用
模糊逻辑首先被提出是有Lotfi在加州大学伯克利分校在1965年的一篇论文。他阐述了他的观点在1973年的一篇论文的概念,介绍了语言变量”,在这篇文章中相当于一个变量定义为一个模糊集合。其他研究打乱了,第二次工业应用中,水泥窑建在丹麦,即将到来的在线1975。
模糊系统在很大程度上在美国被忽略了,因为他们更多关注的是人工智能，一个被过分吹嘘的领域，尤其是在1980年中期年代,导致在诚信缺失的商业领域。
然而日本人对这个却没有偏见和忽略，模糊系统引发日立的Seiji Yasunobu和Soji Yasunobu Miyamoto的兴趣。,他于1985年的模拟,证明了模糊控制系统对仙台铁路的控制的优越性。他们的想法是被接受了,并将模糊系统用来控制加速、制动、和停车，当线于1987年开业。
1987年另一项促进模糊系统的兴趣。在一个国际会议在东京的模糊研究那一年,Yamakawa论证<使用模糊控制,通过一系列简单的专用模糊逻辑芯片,在一个“倒立摆“实验。这是一个经典的控制问题,在这一过程中,车辆努力保持杆安装在顶部用铰链正直来回移动。
这次展示给观察者家们留下了深刻的印象,以及后来的实验,他登上一Yamakawa酒杯包含水或甚至一只活老鼠的顶部的钟摆。该系统在两种情况下,保持稳定。Yamakawa最终继续组织自己的fuzzy-systems研究实验室帮助利用自己的专利在田地里的时候。
展示之后,日本工程师开发出了大范围的模糊系统用于工业领域和消费领域的应用。1988年,日本建立了国际模糊工程实验室,建立合作安排48公司进行模糊控制的研究。
松下吸尘器使用微控制器运行模糊算法去控制传感器和调整吸尘力。日立洗衣机用模糊控制器Load-Weight,Fabric-Mix和尘土传感器及自动设定洗涤周期来最佳利用电能、水和洗涤剂。
佳能研制出的一种上相机使用电荷耦合器件(CCD)测量中的图像清晰的六个区域其视野和使用提供的信息来决定是否这个影像在焦点上(清晰)。它也可以追踪变化的速率在镜头运动的重点,以及它的速度以防止控制超调。相机的模糊控制系统采用12输入,6个输入了解解现行清晰所提供的数据和其他6个输入测量CCD镜头的变化率的运动。输出的位置是镜头。模糊控制系统应用13条规则,需要1.1 千字节记忆信息。
另外一个例子是,三菱工业空调设计采用25加热规则和25冷却规则。温度传感器提供输入,输出一个控制逆变器,一个压缩机气阀,风扇电机。和以前的设计相比,新设计的模糊控制器增加五次加热冷却速度,降低能耗24%,增加温度稳定性的一个因素两个,使用较少的传感器。
日本人对模糊逻辑的人情是反映在很广泛的应用范围上,他们一直在研究或实现:例如个性和笔迹识别光学模糊系统,机器人,声控机器人直升飞机。
模糊系统的相关研究工作也在美国和欧洲进行着。美国环境保护署分析了模糊控制节能电动机,美国国家航空和宇宙航行局研究了模糊控制自动太空对接。仿真结果表明,模糊控制系统可大大降低燃料消耗。如波音公司、通用汽车、艾伦-布拉德利、克莱斯勒、伊顿,和漩涡了模糊逻辑用于低功率冰箱、改善汽车变速箱。在1995年美泰克公司推出的一个“聪明”基于模糊控制器洗碗机，“一站式感应模块”包括热敏电阻器,用来温度测量;电导率传感器,用来测量离子洗涤剂水平存在于洗;分散和浊度传感器用来检测透射光测量失禁的洗涤,以及一个磁致伸缩传感器来读取旋转速率。这个系统确定最优洗周期任何载荷,获得最佳的结果用最少的能源、洗涤剂、和水。
研究和开发还继续模糊应用软件,作为反对固件设计,包括模糊专家系统模糊逻辑与整合神经网络和所谓的自适应遗传软件系统,其最终目的是建立“自主学习”模糊控制系统。
模糊集
输入变量在一个模糊控制系统是集映射到一般由类似的隶属度函数,称为“模糊集”。转换的过程中,一个干脆利落的输入值模糊值称为“模糊化”。
一个控制系统也有各种不同的类型开关或“开关”,连同它的模拟输入输入,而这样的开关输入当然总有一个真实的价值等于要么1或0,但该方案能对付他们,简单的模糊函数,要么发生一个值或另一个。
赋予了“映射输入变量的隶属函数和进入真理价值,单片机然后做出决定为采取何种行动基于一套“规则”,每一组的形式。
在一个例子里,有两个输入变量是“刹车温度”和“速度”,定义为模糊集值。输出变量,“制动压力” ,也定义为一个模糊集,有价值观像“静”、“稍微增大”“略微下降”,等等。
这条规则本身很莫名其妙,因为它看起来好像可以使用，会干扰到与模糊,但要记住,这个决定是基于一套规则。
所有的规则都调用申请,使用模糊隶属度函数和诚实得到输入值,确定结果的规则。这个结果将被映射成一个隶属函数和控制输出变量的真值。
这些结果相结合,给出了具体的(“脆”)的答案,实际的制动压力,一个过程被称为解模糊化，结合了模糊操作规则 "推理“描述”模糊专家系统”。
传统的控制系统是基于数学模型的控制系统,描述了使用一个或更多微分方程确定系统回应其输入。这类系统通常被作为“PID控制器”他们是产品的数十年的发展建设和理论分析,是非常有效的。
如果PID和其他传统的控制系统是如此的先进,何必还要模糊控制吗?它有一些优点。在许多情况下,数学模型的控制过程可能不存在,或太“贵”的认识论的计算机处理能力和内存,与系统的基于经验规则可能更有效。
此外,模糊逻辑都适合低成本实现基于廉价的传感器、低分辨率模拟/数字转换器,或8位单片机芯片one-chip 4比特。这种系统可以很容易地通过增加新的规则升级来提高性能或添加新功能。在许多情况下,模糊控制可以用来改善现有的传统控制器系统通过增加了额外的情报电流控制方法。
模糊控的细节
模糊控制器是很简单的理念上。它们是由一个输入阶段,一个处理阶段,一个输
出阶段。地图传感器输入级或其他输入,比如开关等等,到合适的隶属函数和真理的价值。每一个适当的加工阶段调用规则和产生的结果对每个人来说,然后结合结果的规则。最后,将结果输出阶段相结合的具体控制输出回他的价值。
最常见的形状是三角形的隶属度函数,尽管梯形和贝尔曲线也使用,但其形状通常比数量更重要曲线及其位置。从三人至七人通常是适当的覆盖曲线所需要的范围的一个输入值,或“宇宙的话语“在模糊术语。
作为讨论之前,加工阶段是基于规则的集合的形式逻辑IF - THEN报表,那里的部分叫做“之前”和后来的部分被称为“随之”。典型的模糊控制系统具有几十个规则。
这条规则的价值采用真理“温”的输入,真值的“冷”,产生的结果,在模糊集的“加热器“输出,“高”的价值。这个结果是用来与其他规则的结果,最终产生脆复合输出。很明显,越是真理价值的“冷”,真值越高,“高”,但这并不一定就意味着输出本身会被设置为“高”,因为这是唯一准则在许多。在某些情况下,隶属函数可以修正“篱笆”相当于形容词。模糊限制语包括“关于“常见,“近”、“接近”、“大约”、“很”、“稍微”、“太”、“非常”、“有点”。这些操作可能有明确的定义,虽然可能有很大差别的定义不同的实现。“非常”,因为一个典型的例子,广场隶属函数;因为会员价值总是小于1,这减少了隶属函数。“非常”立方体价值观提供更大的缩小,而“有点“扩大功能以平方根的计算。
在实践中,模糊规则集,通常有几个来路综合利用模糊运算,如,或者,不,虽然再次定义每每变化,在一个受欢迎的定义,只是利用最小重量的雏形,而或采用最大值。还有一个不经营者一个隶属函数减去从1到给“补充性”功能。
有几种方法可以定义一个规则的结果,而是一种最常见的和最简单的是“极大极小“推理法,给出了输出隶属函数的真值所产生的前提。
规则可以解决并联在硬件或软件。顺序结果所有的规则，其中的几个方法。在理论上有几十个,每个都有各种各样的优点和缺点。
“质心”的方法很受欢迎,在“的质心”的结果提供了清新的价值。另一个方法是“高度”方法,它以价值的主要因素。方法更利于统治质心与输出最大的区域,而高程法显然更利于规则和最大的输出值。
模糊控制系统的设计是基于经验方法,基本上一个系统的方法试误。大致过程如下:
1.文件系统的操作规范和输入与输出。
2.文档模糊集的输入。
3.文件规则集。
4.确定解模糊化方法确定。
5.运行测试套件验证通过制度,调整细节的要求。
6.完整的文件,发布给生产。
逻辑解释模糊控制
尽管有几个困难出现给一个严谨的逻辑解释If - Then规则。作为一个例子,解释一个规则,因为如果(温度是“冷”),那么(加热器是“高”)由第一阶表达式冷)
(r是假的。然后公式冷)
(r→高)(t是适用于(x→高)
(y和假设r是一个输入这样冷)
任何一个师,因此任何不正确的控制提供了一种给r。很明显,如果我们考虑系统的先例的规则类定义一个分区这样一个自相矛盾的现象不会出现。在任何情况下它有时是不考虑两个变量x和y在一条规则没有某种功能的依赖。严谨的逻辑正当化中给出的模糊控制Hajek的书,被描绘成一个模糊控制理论的基本Hajek逻辑。在2005 Gerla模糊控制逻辑方法,提出了一种基于以下的想法。f模糊函数表示的系统与模糊控制相结合,即:给定输入r,)
f
y
s 是模糊集合可能的输出。然后给出一个
r
(y
,
(
)
可能的输出的t,我们把),
(t
f为真理程度的表示。更多的是任何系统的If - Then
r
规则可转化为一个模糊的程序,在这种情况下模糊函数f模糊谓词的解释很好x在相关的最小模糊Herbrand模型。以这样一种方式成为一个章模糊控制的模(y
)
,
糊逻辑编程。学习过程成为一个问题属于归纳逻辑理论。
Fuzzy Control
From Wikipedia 20 November 2011
Overview
Fuzzy logic is widely used in machine control. The term itself inspires a certain skepticism, sounding equivalent to "half-baked logic" or "bogus logic", but the "fuzzy" part does not refer to a lack of rigour in the method, rather to the fact that the logic involved can deal with concepts that cannot be expressed as "true" or "false" but rather as "partially true". Although genetic algorithms and neural networks can perform just as well as fuzzy logic in many cases, fuzzy logic has the advantage that the solution to the problem can be cast in terms that human operators can understand, so that their experience can be used in the design of the controller. This makes it easier to mechanize tasks that are already successfully performed by humans.
History and applications
Fuzzy logic was first proposed by Lotfi A. Zadeh of the University of California at Berkeley in a 1965 paper. He elaborated on his ideas in a 1973 paper that introduced the concept of "linguistic variables", which in this article equates to a variable defined as a fuzzy set. Other research followed, with the first industrial application, a cement kiln built in Denmark, coming on line in 1975.
Fuzzy systems were largely ignored in the U.S. because they were associated with artificial intelligence, a field that periodically oversells itself, especially in the mid-1980s, resulting in a lack of credibility within the commercial domain.
The Japanese did not have this prejudice. Interest in fuzzy systems was sparked by Seiji Yasunobu and Soji Miyamoto of Hitachi, who in 1985 provided simulations that demonstrated the superiority of fuzzy control systems for the Sendai railway. Their ideas were adopted, and fuzzy systems were used to control accelerating, braking, and stopping when the line opened in 1987.
Another event in 1987 helped promote interest in fuzzy systems. During an international meeting of fuzzy researchers in Tokyo that year, Takeshi Yamakawa demonstrated the use of fuzzy control, through a set of simple dedicated fuzzy logic chips, in an "inverted pendulum" experiment. This is a classic control problem, in which a vehicle tries to keep a pole mounted on its top by a hinge upright by moving back and forth.
Observers were impressed with this demonstration, as well as later experiments by Yamakawa in which he mounted a wine glass containing water or even a live mouse to the top of the pendulum. The system maintained stability in both cases. Yamakawa eventually went on to organize his own fuzzy-systems research lab to help exploit his patents in the field.
Following such demonstrations, Japanese engineers developed a wide range of fuzzy systems for both industrial and consumer applications. In 1988 Japan established
the Laboratory for International Fuzzy Engineering (LIFE), a cooperative arrangement between 48 companies to pursue fuzzy research.
Matsushita vacuum cleaners use micro controllers running fuzzy algorithms to interrogate dust sensors and adjust suction power accordingly. Hitachi washing machines use fuzzy controllers to load-weight, fabric-mix, and dirt sensors and automatically set the wash cycle for the best use of power, water, and detergent.
Canon developed an autofocusing camera that uses a charge-coupled device (CCD) to measure the clarity of the image in six regions of its field of view and use the information provided to determine if the image is in focus. It also tracks the rate of change of lens movement during focusing, and controls its speed to prevent overshoot.The camera's fuzzy control system uses 12 inputs: 6 to obtain the current clarity data provided by the CCD and 6 to measure the rate of change of lens movement. The output is the position of the lens. The fuzzy control system uses 13 rules and requires 1.1 kilobytes of memory.
As another example of a practical system, an industrial air conditioner designed by Mitsubishi uses 25 heating rules and 25 cooling rules. A temperature sensor provides input, with control outputs fed to an inverter, a compressor valve, and a fan motor. Compared to the previous design, the fuzzy controller heats and cools five times faster, reduces power consumption by 24%, increases temperature stability by a factor of two, and uses fewer sensors.
The enthusiasm of the Japanese for fuzzy logic is reflected in the wide range of other applications they have investigated or implemented: character and handwriting recognition; optical fuzzy systems; robots, voice-controlled robot helicopters Work on fuzzy systems is also proceeding in the US and Europe. The US Environmental Protection Agency has investigated fuzzy control for energy-efficient motors, and NASA has studied fuzzy control for automated space docking: simulations show that a fuzzy control system can greatly reduce fuel consumption. Firms such as Boeing, General Motors, Allen-Bradley, Chrysler, Eaton, and Whirlpool have worked on fuzzy logic for use in low-power refrigerators, improved automotive transmissions, and energy-efficient electric motors.
In 1995 Maytag introduced an "intelligent" dishwasher based on a fuzzy controller and a "one-stop sensing module" that combines a thermistor, for temperature measurement; a conductivity sensor, to measure detergent level from the ions present in the wash; a turbidity sensor that measures scattered and transmitted light to measure the soiling of the wash; and a magnetostrictive sensor to read spin rate. The system determines the optimum wash cycle for any load to obtain the best results with the least amount of energy, detergent, and water.
Research and development is also continuing on fuzzy applications in software, as opposed to firmware, design, including fuzzy expert systems and integration of fuzzy logic with neural-network and so-called adaptive "genetic" software systems, with the ultimate goal of building "self-learning" fuzzy control systems.
Fuzzy sets
The input variables in a fuzzy control system are in general mapped into by sets of membership functions similar to this, known as "fuzzy sets". The process of converting a crisp input value to a fuzzy value is called "fuzzification".
A control system may also have various types of switch, or "ON-OFF", inputs along with its analog inputs, and such switch inputs of course will always have a truth value equal to either 1 or 0, but the scheme can deal with them as simplified fuzzy functions that happen to be either one value or another.
Given "mappings" of input variables into membership functions and truth values, the microcontroller then makes decisions for what action to take based on a set of "rules", each of the form.
In one example, the two input variables are "brake temperature" and "speed" that have values defined as fuzzy sets. The output variable, "brake pressure", is also defined by a fuzzy set that can have values like "static", "slightly increased", "slightly decreased", and so on.
This rule by itself is very puzzling since it looks like it could be used without bothering with fuzzy logic, but remember that the decision is based on a set of rules: All the rules that apply are invoked, using the membership functions and truth values obtained from the inputs, to determine the result of the rule.
This result in turn will be mapped into a membership function and truth value controlling the output variable.
These results are combined to give a specific ("crisp") answer, the actual brake pressure, a procedure known as "defuzzification".
This combination of fuzzy operations and rule-based "inference" describes a "fuzzy expert system".
Traditional control systems are based on mathematical models in which the control system is described using one or more differential equations that define the system response to its inputs. Such systems are often implemented as "PID controllers" (proportional-integral-derivative controllers). They are the products of decades of development and theoretical analysis, and are highly effective.
If PID and other traditional control systems are so well-developed, why bother with fuzzy control? It has some advantages. In many cases, the mathematical model of the control process may not exist, or may be too "expensive" in terms of computer processing power and memory, and a system based on empirical rules may be more effective.
Furthermore, fuzzy logic is well suited to low-cost implementations based on cheap sensors, low-resolution analog-to-digital converters, and 4-bit or 8-bit one-chip microcontroller chips. Such systems can be easily upgraded by adding new rules to improve performance or add new features. In many cases, fuzzy control can be used to improve existing traditional controller systems by adding an extra layer of intelligence to the current control method.
Fuzzy control in detail
Fuzzy controllers are very simple conceptually. They consist of an input stage, a processing stage, and an output stage. The input stage maps sensor or other inputs, such as switches, thumbwheels, and so on, to the appropriate membership functions and truth values. The processing stage invokes each appropriate rule and generates a result for each, then combines the results of the rules. Finally, the output stage converts the combined result back into a specific control output value.
The most common shape of membership functions is triangular, although trapezoidal and bell curves are also used, but the shape is generally less important than the number of curves and their placement. From three to seven curves are generally appropriate to cover the required range of an input value, or the "universe of discourse" in fuzzy jargon.
As discussed earlier, the processing stage is based on a collection of logic rules in the form of IF-THEN statements, where the IF part is called the "antecedent" and the THEN part is called the "consequent".
This rule uses the truth value of the "temperature" input, which is some truth value of "cold", to generate a result in the fuzzy set for the "heater" output, which is some value of "high". This result is used with the results of other rules to finally generate the crisp composite output. Obviously, the greater the truth value of "cold", the higher the truth value of "high", though this does not necessarily mean that the output itself will be set to "high" since this is only one rule among many. In some cases, the membership functions can be modified by "hedges" that are equivalent to adjectives. Common hedges include "about", "near", "close to", "approximately", "very", "slightly", "too", "extremely", and "somewhat". These operations may have precise definitions, though the definitions can vary considerably between different implementations. "Very", for one example, squares membership functions; since the membership values are always less than 1, this narrows the membership function. "Extremely" cubes the values to give greater narrowing, while "somewhat" broadens the function by taking the square root.
In practice, the fuzzy rule sets usually have several antecedents that are combined using fuzzy operators, such as AND, OR, and NOT, though again the definitions tend to vary: AND, in one popular definition, simply uses the minimum weight of all the antecedents, while OR uses the maximum value. There is also a NOT operator that subtracts a membership function from 1 to give the "complementary" function.
There are several ways to define the result of a rule, but one of the most common and simplest is the "max-min" inference method, in which the output membership function is given the truth value generated by the premise.
Rules can be solved in parallel in hardware, or sequentially in software. The results of all the rules that have fired are "defuzzified" to a crisp value by one of several methods. There are dozens in theory, each with various advantages and drawbacks.
The "centroid" method is very popular, in which the "center of mass" of the result provides the crisp value. Another approach is the "height" method, which takes the value of the biggest contributor. The centroid method favors the rule with the output of
greatest area, while the height method obviously favors the rule with the greatest output value.
The diagram below demonstrates max-min inferring and centroid defuzzification for a system with input variables "x", "y", and "z" and an output variable "n". Note that "mu" is standard fuzzy-logic nomenclature for "truth value":
Fuzzy control system design is based on empirical methods, basically a methodical approach to trial-and-error. The general process is as follows:
1.Document the system's operational specifications and inputs and outputs.
2.Document the fuzzy sets for the inputs.
3.Document the rule set.
4.Determine the defuzzification method.
5.Run through test suite to validate system, adjust details as required.
https://www.doczj.com/doc/0213743346.html,plete document and release to production.
Logical interpretation of fuzzy control
In spite of the appearance there are several difficulties to give a rigorous logical interpretation of the IF-THEN rules. As an example, interpret a rule as IF (temperature is "cold") THEN (heater is "hig h") by the first order formula Cold(x)→High(y) and assume that r is an input such that Cold(r) is false. Then the formula Cold(r)→High(t) is true for any t and therefore any t gives a correct control given r. Obviously, if we consider systems of rules in which the class antecedent define a partition such a paradoxical phenomenon does not arise. In any case it is sometimes unsatisfactory to consider two variables x and y in a rule without some kind of functional dependence. A rigorous logical justification of fuzzy control is given in Hájek's book ,where fuzzy control is represented as a theory of Hájek's basic logic. Also in Gerla 2005 a logical approach to fuzzy control is proposed based on the following idea. Denote by f the fuzzy function associated with the fuzzy control system, i.e., given the input r, s(y) = f(r,y) is the fuzzy set of possible outputs. Then given a possible output 't', we interpret f(r,t) as the truth degree of the claim "t is a good answer given r". More formally, any system of IF-THEN rules can be translate into a fuzzy program in such a way that the fuzzy function f is the interpretation of a vague predicate Good(x,y) in the associated least fuzzy Herbrand model. In such a way fuzzy control becomes a chapter of fuzzy logic programming. The learning process becomes a question belonging to inductive logic theory.
外文翻译 原文 World Trade and International Trade Material Source:https://www.doczj.com/doc/0213743346.html, Author: Ted Alax In today’s complex economic world, neither individuals nor nations are self-sufficient. Nations have utilized different economic resources; people have developed different skills. This is the foundation of world trade and economic activity. As a result of this trade and activity, international finance and banking have evolved. For example, the United States is a major consumer of coffee, yet it does not have the climate to grow any or its own. Consequently, the United States must import coffee from countries (such as Brazil, Colombia and Guatemala) that grow coffee efficiently. On the other hand, the United States has large industrial plants capable of producing a variety of goods, such as chemicals and airplanes, which can be sold to nations that need them. If nations traded item for item, such as one automobile for 10,000 bags of coffee, foreign trade would be extremely cumbersome and restrictive. So instead of batter, which is trade of goods without an exchange of money, the United State receives money in payment for what it sells. It pays for Brazilian coffee with dollars, which Brazil can then use to buy wool from Australia, which in turn can buy textiles Great Britain, which can then buy tobacco from the United State. Foreign trade, the exchange of goods between nations, takes place for many reasons. The first, as mentioned above is that no nation has all of the commodities that it needs. Raw materials are scattered around the world. Large deposits of copper are mined in Peru and Zaire, diamonds are mined in South Africa and petroleum is recovered in the Middle East. Countries that do not have these resources within their own boundaries must buy from countries that export them. Foreign trade also occurs because a country often does not have enough of a particular item to meet its needs. Although the United States is a major producer of sugar, it consumes more than it can produce internally and thus must import sugar.
企业成本控制外文翻译文献(文档含英文原文和中文翻译)
译文： 在价值链的成本控制下减少费用和获得更多的利润 摘要： 根据基于价值链的成本管理理念和基于价值的重要因素是必要的。首先，必须有足够的资源，必须创造了有利的价值投资，同时还需要基于客户价值活动链，以确定他们的成本管理优势的价值链。其次，消耗的资源必须尽量减少，使最小的运营成本价值链和确保成本优势是基于最大商业价值或利润，这是一种成本控制系统内部整个视图的创建和供应的具实践，它也是一种成本控制制度基于价值链，包括足够的控制和必要的资源投资价值的观点，创建和保持消费的资源到合理的水平，具有价值的观点主要对象的第一个因素是构造有利的价值链，从创造顾客价值开始；第二个因素是加强有利的价值链，从供应或生产客户价值开始。因此它是一个新型的理念，去探索成本控制从整个视图的创建和供应的商品更盈利企业获得可持续的竞争优势。 关键词：成本控制，价值链，收益，支出，收入，成本会计 1、介绍 根据价值链理论，企业的目的是创造最大的顾客价值；和企业的竞争优势在于尽可能提供尽可能多的价值给他们的客户，作为低成本可能的。这要求企业必须首先考虑他们是否能为顾客创造价值，和然后考虑在很长一段时间内如何创造它。然而，竞争一直以“商品”（或“产品”）作为最直接的载体，因此，传统的成本控制方法主要集中在对“产品”和生产流程的过程。很显然，这不能解决企业的问题，企业是否或如何能为客户创造价值。换句话说，这至少不能从根本上解决它。 因此，企业必须首先投入足够的资源，以便他们能够创建客户值取向，然后提供它以最少的资源费用。所以在整个视图中对价值创造和提供整体的观点来控制成本，它可以为客户提供完美的动力和操作运行机制运行成本的控制，也可以从根本上彻底克服了传统的成本控制方法的缺点，解决了无法控制的创造和供应不足的真正价值。基于此，本文试图从创作的整体观讨论成本控制提供价值并探讨实现良性循环的策略，也就是说，“创造价值投资成本供应价值创造价值”。 2、成本及其控制的基于价值链理念 2.1基于价值链的成本观念 根据价值链理论，如果企业是要被客户接受，它必须创造和提供能满足其客户的价值。因此，成本（价值或资源支付费用）这不离为创造和提供顾客价值的活动，其活动的价值链。因此，我们应该从价值链角度看成本的重要。
Step Motor Motor&&Servo Motor Systems and Controls Motion Architect?Software Does the Work for You...Configure,Diagnose,Debug Compumotor’s Motion Architect is a Microsoft?Windows?-based software development tool for6000Series products that allows you to automatically generate commented setup code,edit and execute motion control programs,and create a custom operator test panel.The heart of Motion Architect is the shell,which provides an integrated environment to access the following modules. ?System Configurator—This module prompts you to fill in all pertinent set-up information to initiate motion.Configurable to the specific6000Series product that is selected,the information is then used to generate actual6000-language code that is the beginning of your program. ?Program Editor—This module allows you to edit code.It also has the commands available through“Help”menus.A user’s guide is provided on disk. ?Terminal Emulator—This module allows you to interact directly with the6000product.“Help”is again available with all commands and their definitions available for reference.?Test Panel—You can simulate your programs,debug programs,and check for program flow using this module. Motion Architect?has been designed for use with all6000Series products—for both servo and stepper technologies.The versatility of Windows and the6000Series language allow you to solve applications ranging from the very simple to the complex. Motion Architect comes standard with each of the6000Series products and is a tool that makes using these controllers even more simple—shortening the project development time considerably.A value-added feature of Motion Architect,when used with the6000 Servo Controllers,is its tuning aide.This additional module allows you to graphically display a variety of move parameters and see how these parameters change based on tuning values. Using Motion Architect,you can open multiple windows at once.For example,both the Program Editor and Terminal Emulator windows can be opened to run the program,get information,and then make changes to the program. On-line help is available throughout Motion Architect,including interactive access to the contents of the Compumotor6000Series Software Reference Guide. SOLVING APPLICATIONS FROM SIMPLE TO COMPLEX Servo Control is Yours with Servo Tuner Software Compumotor combines the6000Series servo controllers with Servo Tuner software.The Servo Tuner is an add-on module that expands and enhances the capabilities of Motion Architect?. Motion Architect and the Servo Tuner combine to provide graphical feedback of
文献出处：Borkar S, Koranne S. Study of Service Quality Management in Hotel Industry [J]. Pacific Business Review International, 2014, 6(9): 21-25. 原文 Study of Service Quality Management in Hotel Industry Borkar; Sameer Abstract It is an attempt to understand the role of quality improvement process in hospitality industry and effectiveness in making it sustainable business enterprise. It is a survey of the presently adopted quality management tools which are making the hotels operations better focused and reliable and meet the customer expectations. Descriptive research design is used to know the parameters of service quality management in hospitality industry. Exploratory research design is undertaken to dig out the service quality management practices and its effectiveness. Data analysis is done and presented; hypothesis is tested against the collected data. Since the industry continuously tries to improve upon their services to meet the levels of customer satisfaction; Study presents tools for continuous improvement process and how it benefits all the stake holders. It can be inferred from the study that the hotel implement continuous improvement process and quality management tools to remain competitive in the market. The study involves hotels of highly competitive market with limited number of respondents. This limits the study to hotel industry and has scope of including other hospitality service providers as well. Keywords:Customer Satisfaction, Perception, Performance Measurement, Continuous, Improvement Process. Introduction It has brought paradigm shifts in the operations of hospitality industry. The overall perspective of the industry is changed due to introduction of new techniques
Positioning in Practice Strategic Role of Marketing For large firms that have two or more strategic business units (SBUs), there are generally three levels of strategy: corporate-level strategy, strategic-business-unit-level (or business-level) strategy, and marketing strategy. A corporate strategy provides direction on the company's mission, the kinds of businesses it should be in, and its growth policies. A business-level strategy addresses the way a strategic business unit will compete within its industry. Finally, a marketing strategy provides a plan for pursuing the company's objectives within a specific market segment. Note that the higher level of strategy provides both the objectives and guidelines for the lower level of strategy. At corporate level, management must coordinate the activities of multiple strategic business units. Thus the decisions about the organization's scope and appropriate resource deployments/allocation across its various divisions or businesses are the primary focus of corporate strategy.Attempts to develop and maintain distinctive competencies tend to focus on generating superior financial, capital, and human resources; designing effective organizational structures and processes; and seeking synergy among the firm's various businesses. At business-level strategy, managers focus on how the SBU will compete within its industry. A major issue addressed in business strategy is how to achieve and sustain a competitive advantage. Synergy for the unit is sought across product-markets and across functional department within the unit. The primary purpose of a marketing strategy is to effectively allocate and coordinate marketing resources and activities to accomplish the firm's objectives within a specific product-market. The decisions about the scope of a marketing strategy involve specifying the target market segment(s) to pursue and the breadth of the product line to offered. At this level of strategy, firms seek competitive advantage and synergy through a well-integrated program of marketing mix elements tailored to the needs and wants of customers in the target segment(s). Strategic Role of Positioning Based on the above discussion, it is clear that marketing strategy consists of two parts: target market strategy and marketing mix strategy. Target market strategy consists of three processes: market segmentation, targeting (or target market selection), and positioning. Marketing mix strategy refers to the process of creating a unique
智能汽车中英文对照外文翻译文献 (文档含英文原文和中文翻译) 翻译： 基于智能汽车的智能控制研究 摘要：本文使用一个叫做“智能汽车”的平台进行智能控制研究，该小车采用飞思卡尔半导体公司制造的MC9S12DG128芯片作为主要的控制单元，同时介绍了最小的智能控制系统的设计和实现智能车的自我追踪驾驶使用路径识别算法。智能控制智能车的研究包括:提取路径信息,自我跟踪算法实现和方向和速度控制。下文介绍了系统中不同模块的各自实现功能，最重要部分是智能车的过程智能控制：开环控制和闭环控制的应用程序包括增量式PID控制算法和鲁棒控制算法。最后一步是
基于智能控制系统的智能测试。 关键词：MC9S12DG128；智能控制;开环控制；PID；鲁棒； 1.背景介绍 随着控制理论的提高以及信息技术的快速发展,智能控制在我们的社会中发挥着越来越重要的作用。由于嵌入式设备有小尺寸、低功耗、功能强大等优点，相信在这个领域将会有一个相对广泛的应用,如汽车电子、航空航天、智能家居。如果这些技术一起工作，它将会蔓延到其他领域。为了研究嵌入式智能控制技术，“智能汽车”被选为研究平台,并把MC9S12DG128芯片作为主控单元。通过智能控制,智能汽车可以自主移动,同时跟踪的路径。 首先,本文给读者一个总体介绍智能车辆系统的[2、3]。然后,根据智能车辆的智能控制:提取路径信息,自我跟踪算法实现中,舵机的方向和速度的控制。它提供包括了上述四个方面的细节的智能车系统信息。此外,本文强调了智能车的控制过程应用程序包括开环控制、闭环增量PID算法和鲁棒算法。 2.智能车系统的总体设计 该系统采用MC9S12DG128[4]作为主芯片，以及一个CCD传感器作为交通信息收集的传感器。速度传感器是基于无线电型光电管的原理开发。路径可以CCD传感器后绘制收集的数据，并且系统计算出相应的处理。在同时，用由电动马达速度测试模块测量的智能汽车的当前速度进行响应的系统。最后，路径识别系统利用所述路径信息和当前的速度，以使智能汽车在不同的道路条件的最高速度运行。图1示出了智能车辆系统的框图。
数控加工中心技术发展趋势及对策 原文来源：Zhao Chang-ming Liu Wang-ju (CNC Machining Process and equipment, 2002,China) 一、摘要 Equip the engineering level, level of determining the whole national economy of the modernized degree and modernized degree of industry, numerical control technology is it develop new developing new high-tech industry and most advanced industry to equip (such as information technology and his industry, biotechnology and his industry, aviation, spaceflight, etc. national defense industry) last technology and getting more basic most equipment. Numerical control technology is the technology controlled to mechanical movement and working course with digital information, integrated products of electromechanics that the numerical control equipment is the new technology represented by numerical control technology forms to the manufacture industry of the tradition and infiltration of the new developing manufacturing industry, Keywords:Numerical ControlTechnology, E quipment,industry 二、译文 数控技术和装备发展趋势及对策 装备工业的技术水平和现代化程度决定着整个国民经济的水平和现代化程度，数控技术及装备是发展新兴高新技术产业和尖端工业（如信息技术及其产业、生物技术及其产业、航空、航天等国防工业产业）的使能技术和最基本的装备。马克思曾经说过“各种经济时代的区别，不在于生产什么，而在于怎样生产，用什么劳动资料生产”。制造技术和装备就是人类生产活动的最基本的生产资料，而数控技术又是当今先进制造技术和装备最为核心的技术。当今世界各国制造业广泛采用数控技术，以提高制造能力和水平，提高对动态多变市场的适应能力和竞争能力。此外，世界上各工业发达国家还将数控技术及数控装备列为国家的战
互利共赢的供应商质量控制 前言 近年来，随着对供应链的重视，供应商管理正逐渐成为企业和学术界的关注对象，IS0９000族标准以及QS 9０00标准都对供应商的管理提出了相应的要求，与供应商管理有关的研究成果正逐渐增多，一些软件巨头也推出了供应商关系管理的软件，但是在这些研究成果和应用软件中，涉及到的供应商质量控制的内容只是一些最基本的要求，而供应商质量控制恰恰是供应商管理的最基本、最重要的内容。另一方而，质量管理界对质量控制的研究取得了大量的成果，遗憾的是这些成果大多依然局限于企业的内部控制，仅仅研究从企业内部各环节如何改善产品的质量，而基于供应链的角度来研究质量控制的成果尚不多见。因此，系统地研究经济全球化形势下供应商质量控制的理论与方法，将有助于推动我国企业产品质量的快速提高和供应链竞争优势的形成与巩固。 1、质量与企业共存 质量一直是一个随着时代的变化而不断变化的概念,人们对质量的认识也往往因关注点不同而有所不同。如，早在1908年，通用汽车公司的工程师们在皇家汽车俱乐部会员们的面前拆解了3辆凯迪拉克轿车，并把这些零件混在一起,而后从中选择零件重新组装成车，然后驾车绝尘而去。这令在场的会员极为震惊，认为凯迪拉克车质量之高令人惊叹。显然在当时，汽车零件具有互换性是一种了不起的质量特性,这也是福特公司的Ｎ型车和T型车取得辉煌成功的重要原因.时至今日，即使农用三轮车的零部件也具有极高的互换性，零部件的标准化和互换性已经是理所当然的事情，不再是吸引顾客的重要质量特性.可见质量的内涵是不断变化的.那么究竟什么是质量呢？ （１)市场竟争就是企业间对“顾客”的争夺，在日益激烈的“顾客"争夺战中，质量、价格、交付（交付日期、方式和手段）和服务是企业常用的四个法宝，其中质量是根本，离开质量其他三项将变得毫无意义，因此可以说质量己成为市场竞争的焦点.它反映了产品是否能够反映顾客需求、能否满足顾客需求，从面决定了产品的市场前途。有鉴于此，质量己成为一项全球性运动,世界上所有优秀企业无一不把质量作为企业战略的关键内容，从战略的角度来规划质量。 （2）对于企业经营者来说,认识到质量对企业的重要意义只是经营企业的第一步,重要的是如何利用科学的方法来保证产品和服务的质量，使顾客满意，来保证过程和工作的质量来获互利共炭的供应商质量控制得良好的业绩。 众所周知,企业管理是社会生产力发展到一定程度的历史产物,质量管理作为企业管理的组成部分,同样也是社会发展的客观要求，特别是顾客处于主导地位的今天,要使顾客满意，就必须有过硬的产品质量和服务质量，这就要求企业积极推行先进的质量管理理论与方法，不断进行质量管理创新. ２、企业与供应商质量控制 随着生产社会化的不断发展，企业的生产活动分工越来越细,专业化程度越来越强，促使生产技术水平越来越高,产品质量得到大幅度改善。通常，某一产品不可能由一个企业从最初的原材料开始加工直至形成顾客最终使用的产品，往往是通过多个企业分工协作来完成.另外，先进生产方式的广泛应用,如准时生产、敏捷制造、零库存等，使企业与供应商的关系愈加紧密，企业与供应商的关系也由单纯的买卖关系向互利共底的合作关系演变。 ISO 900０族标准自1987年诞生以来受到了世界各国的一致追捧,全球约５0多万家企业通过ISO90０1质量管理体系认证足以说明这套管理标准在引领国际管理潮流方面的巨大成功。在备受企业欢迎的新版标准ＩSO9000：2０00中，互利的供应商关系被作为八项质量管理原则之一，充分体现了供应商关系管理在企业经营实践中的作用和价值。企业要贯彻这一原则,就必须
跨境电商外文文献综述 (文档含英文原文和中文翻译) 译文: 本地化跨境电子商务的模型 摘要 通过对国际供应链的B2B电子商务交易量的快速增长和伊朗快速增加的跨境交易业务，跨境电商过程的有效管理对B2B电子商务系统十分重要。本文对局部模型的结构是基于B2B电子商务的基础设施三大层，消息层、业务流程层和内容层。由于伊朗的电子商务的要求，每一层的需要适当的标准和合适的方案的选择。当电子文件需要移动顺利向伊朗，建议文件的标准为文件内容支持纸质和电子文件阅读。验证提出的模型是通过案例研究方法呈现一到四阶段的情景。本文试图通过交换商业文件在贸易过程中这一局部模型，实现在全球电子贸易供应链更接近区域单一窗口建设的关键目标。 关键词：电子商务;跨境贸易;电子文档管理;国际供应链
1.简介 电子商务是关于在互联网或其他网络电子系统购买和销售产品或服务。术语B2B（企业对企业），描述了企业间的电子商务交易，如制造商和批发商，或批发商和零售商之间。本文的研究目标是上两个不同国家贸易商之间的通信。今天的世界贸易组织的主要目标之一是建立区域单一窗口，可以提高世界各地的贸易便利化。建立区域单一窗口需要跨境海关，可以有效地交换贸易文件。因此，首先，简化跨境贸易文件的关键在于朝着国家单一窗口移动。然后，区域单一窗口可以授权国家之间的通信。电子商务模型是基于三个主要逻辑层的研究。这三个层消息传输层，业务处理层和内容层。本文的局部模型是一种能够自动交换读取文件的过程。通过与东亚和中东国家的建立区域单一窗口可以在将来得到改善的更多的互操作性，从而建立伊朗国家单一窗口 在本文的第二部分讨论引进国际供应链中的跨境B2B模式所需的基本概念和标准。第三部分介绍在大的模型中引入的组件功能和范围。第四部分讨论了B2B交易层模型的定位，最后结束本文。 2.背景 在本节中，除了了解B2B电子商务在伊朗的情况，还有参考模型的背景等概念以及讨论B2B电子商务跨境模式的本土化。 2.1 B2B电子商务在伊朗 如今伊朗在贸易进程的变现是一个关键的贸易成功点。伊朗和许多其他国家接壤，它的进口和出口过程可以通过公路，铁路，海上和空中的方式来完成。因此，这个国家的中部和战略作用，使得它在亚洲和中东地区货物运输的主要贸易点。今天，在伊朗海关几乎所有的贸易过程通过纸质表格完成，由商务部提供的电子服务仅限于谁该国境内交易的商人。今天，伊朗海关几乎所有的贸易流程都是通过纸质表格来完成的，商务部给出的电子服务只限于该国的商人。介绍了模型试图简化在伊朗交易的跨境电子商务供应链交换电子文件的过程。这里提到的一些系统，由商务部在伊朗的电子服务被提及：进口订单管理系统。贸易统计制度。伊朗法典伊朗。这些电子系统的主要使用，以促进在伊朗贸易过程。这里提到的系统作为独立的贸易者可与建议本文模型在未来的作用。在亚洲的区域性单
本科生毕业设计（论文）外文翻译毕业设计（论文）题目：悬架系统设计与分析 外文题目：An Overview of Disarray in Active Suspension System 译文题目：主动悬架系统杂谈 学生姓名： XXX 专业：车辆工程1002班 指导教师姓名：田国富 评阅日期：
主动悬架系统杂谈 帕蒂尔，维杰河帕蒂尔，加尼甚 助理教授，机械工程系，A.D.C.E.T，阿什达 摘要：当设计一个悬挂系统时，它的双重目标是尽量减少传到乘客的垂直力量和最大限度地提高轮胎与道路接触以提高操控性和安全性。乘客的舒适性与从车身传递的垂直力有关。这个目标可以通过最小化车身的垂直加速度来实现。过度的车轮行驶，将导致轮胎相对路面的非最佳姿态，从而导致差的操控性和附着力。此外，为了保持良好的操控性，轮胎与路面的最佳接触必须保持在四个轮子上。在传统的悬架系统中，这些特点是冲突的，不符合所有条件。因此，在被动悬架系统的基础上，为了改善主动悬架系统，各种各样的研究工作正在进行中。在本文中各种作品的概述已经完成。考虑到季度汽车模型，本文试图给出关于以往的研究和他们的发现对被动和主动悬架系统的参数。 关键词：主动悬架系统，控制系统，动态，被动悬架，车辆。 1.引言 汽车悬架系统的目的是在不同路况下，能保持良好的操控特性和改善乘坐品质。不同的悬架，满足上述要求的程度不同。虽然，可由设计者的聪明才智来改善，就平均而言，悬架的性能主要取决于悬架使用的类型。按改进的性能可以以升序区分为：与被动，半主动和全主动悬架系统，输入的力通常由液压致动器提供。为主动悬架系统设计的机电致动器的另一种方法将在电子控制和悬架系统之间提供直接接口。 目前，公认的主动悬架有两种形式，一种是制动器和钢板弹簧平行的高带宽主动悬架。第二种是低带宽主动悬架，它的致动器带有一系列的钢板弹簧并且能够控制车身的运动，而簧下质量控制是通过被动阻尼器控制的。汽车悬架的主动控制在传统悬架的基础上又提出了新的改进。主动悬架，包括创建悬挂系统中力的液压致动器。由液压致动器产生的力被用来控制簧上质量的运动，以及簧上和簧下质量之间的相对速度。为了提高车辆的特色，以后将主要对主动悬架的高带宽型进行研究。
伺服电机 1. 伺服电机的定义 伺服电动机又称执行电动机，在自动控制系统中，用作执行元件，把所收到的电信号转换成电动机轴上的角位移或角速度输出。分为直流和交流伺服电动机两大类，其主要特点是，当信号电压为零时无自转现象，转速随着转矩的增加而匀速下降。伺服电机在伺服系统中控制机械元件运转的发动机. 是一种补助马达间接变速装置。伺服电机可使控制速度, 位置精度非常准确。将电压信号转化为转矩和转速以驱动控制对象。转子转速受输入信号控制，并能快速反应，在自动控制系统中作执行元件，且具有机电时间常数小、线性度高、始动电压低等特点。 2. 伺服电机工作原理 1.伺服主要靠脉冲来定位，基本上可以这样理解，伺服电机接收到1 个脉冲，就会旋转1 个脉冲对应的角度，从而实现位移，因为，伺服电机本身具备发出脉冲的功能，所以伺服电机每旋转一个角度，都会发出对应数量的脉冲，这样，和伺服电机接受的脉冲形成了呼应，或者叫闭环，如此一来，系统就会知道发了多少脉冲给伺服电机，同时又收了多少脉冲回来，这样，就能够很精确的控制电机的转动，从而实现精确的定位，可以达到0.001mm有刷电机成本低，结构简单，启动转矩大，调速范围宽，控制容易，需要维护，但维护方便（换碳刷），产生电磁干扰，对环境有要求。无刷电机体积小，重量轻，出力大，响应快，速度高，惯量小，转动平滑，力矩稳定。控制复杂，容易实现智能化，其电子换相方式灵活，可以方波换相或正弦波换相。电机免维护，效率很高，运行温度低，电磁辐射很小，长寿命，可用于各种环境。 2. 交流伺服电机也是无刷电机，分为同步和异步电机，目前运动控制中一般都用同步电机，它的功率范围大，可以做到很大的功率。大惯量，最高转动速度低，且随着功率增大而快速降低。因而适合做低速平稳运行的应用。 3. 永磁交流伺服电动机简介 20 世纪80 年代以来，随着集成电路、电力电子技术和交流可变速驱动技术的发展，永磁交流伺服驱动技术有了突出的发展，各国著名电气厂商相继推出各自的交流伺服电动机和伺服驱动器系列产品并不断完善和更新。交流伺服系统已成为当代高性能伺服系统的主要发展方向，使原来的直流伺服面临被淘汰的危机。90 年代以后，世界各国已经商品化了的交流伺服系统是采用全数字控制的正弦
关于企业质量管理文献综述 摘要：随着新世纪的到来，特别是我国加入WTO后，中国将进一步融入世界经济的主流，质量将成为我国广大企业抓住机遇、迎接严峻挑战的关键。要拓展海外市场，必须靠有竞争力的质量；要保护国内的市场，不再有高关税和政府的过渡保护，也要靠质量的较量。随着科学技术的进步，质量管理的理论和方法有了更大发展。本文综合了质量管理的发展历程，并简要评价，提出看法，以便为企业的质量管理和理论研究提供参考。 关键词：质量管理、管理改进 21世纪是质量的世纪”。随着经济全球化和信息革命的迅猛发展，竞争日益加剧。在“数量”问题已解决的今天，人们将越来越追求和依赖于高质量的产品和服务，而且质量的领域不断拓宽，生活的质量、环境的质量、文化的质量、经济增长的质量更加受到全社会的关注。质量已成为竞争的焦点，不仅关系到企业的生存发展，而且影响到国家经济实力的增强和民族的形象。质量已成为全球经济发展战略的核心问题。 一、质量管理理论的回顾 （一）、质量管理的发展阶段 （1）质量检验阶段（20世纪20-30年代） 生产力迅猛发展，生产过程分工细化、日益复杂，许多美国企业按照泰勒的管理模式，纷纷设立检验部门，使检验与生产分离开来，其最大特点为“事后把关”。（2）统计质量阶段（20世纪40-50年代） 早在20世纪20年代，美国贝尔实验室工程师休哈特就提出“控制与预防缺陷”的概念。主要是利用数理统计原理，预防产生废品并检验产品质量，在方式上由专业质量控制工程师和技术人员承担。但这种方法只是保证生产过程中的产品质量，而不能提高产品本身的质量。 （3）全面质量管理阶段（20世纪60年代至今） 美国的费根堡姆提出，“全面质量是为了能够在最经济的水平上，并考虑到充分满足顾客要求的条件下进行生产和提供服务，将企业各部门研制质量、维持质量和提高质量的活动构成为一体的一种有效体系”。 （二）、质量管理的理论流派 1、事后检验 20世纪，美国工程师泰勒提出“科学管理理论”，1911 年泰勒出版了专
外文翻译 原文 Foreign T rade o f China Material Source:W anfang Database Author:Hitomi Iizaka 1.Introduction On December11,2001,China officially joined the World T rade Organization(WTO)and be c a me its143rd member.China’s presence in the worl d economy will continue to grow and deepen.The foreign trade sector plays an important andmultifaceted role in China’s economic development.At the same time, China’s expanded role in the world economy is beneficial t o all its trading partners. Regions that trade with China benefit from cheaper and mor e varieties of imported consumer goods,raw materials and intermediate products.China is also a large and growing export market.While the entry of any major trading nation in the global trading system can create a process of adjustment,the o u t c o me is fundamentally a win-win situation.In this p aper we would like t o provide a survey of the various institutions,laws and characteristics of China’s trade.Among some of the findings, we can highlight thefollowing: ?In2001,total trade to gross domestic pr oduct(GDP)ratio in China is44% ?In2001,47%of Chinese trade is processed trade1 ?In2001,51%of Chinese trade is conduct ed by foreign firms in China2 ?In2001,36%of Chinese exports originate from Gu an gdon g province ?In2001,39%of China’s exports go through Hong Kong to be re-exported elsewhere 2.Evolution of China’s Trade Regime Equally remarkable are the changes in the commodity composition of China’s exports and imports.Table2a shows China’s annu al export volumes of primary goods and manufactured goods over time.In1980,primary goods accounted for 50.3%of China’s exports and manufactured goods accounted for49.7%.Although the share of primary good declines slightly during the first half of1980’s,it remains at50.6%in1985.Since then,exports of manufactured goods have grown at a much