论文中英文翻译(译文)（模版）

第一篇：论文中英文翻译(译文)（模版）

编号： 桂林电子科技大学信息科技学院

毕业设计(论文)外文翻译

（译文）

系别：电子工程系

专业：电子信息工程

学生姓名：韦 骏

学号：0852100329

指导教师单位：姓名：

职称：讲 师

2012年 6月 5日

设计与实现基于 Modbus 协议的嵌入式 Linux 系统

摘要：随着嵌入式计算机技术的飞速发展，新一代工业自动化数据采集和监测系统，采用核心的高性能嵌入式微处理器的，该系统很好地适应应用程序。它符合消费等的严格要求的功能，如可靠性，成本，尺寸和功耗等。在工业自动化应用系统，Modbus 通信协议的工业标准，广泛应用于大规模的工业设备系统，包括 DCS，可编程控制器，RTU 及智能仪表等。为了达到嵌入式数据监测的工业自动化应用软件的需求，本文设计了嵌入式数据采集监测平台下基于 Modbus 协议的 Linux 环境采集系统。串行端口的 Modbus 协议是实现主/从式，其中包括两种通信模式：ASCII 和 RTU。因此，各种药膏协议的设备能够满足串行的 Modbus通信。在 Modbus 协议的嵌入式平台实现稳定和可靠。它在嵌入式数据监测自动化应用系统的新收购的前景良好。关键词：嵌入式系统，嵌入式 Linux，Modbus 协议，数据采集，监测和控制。

1、绪论

Modbus 是一种通讯协议，是一种由莫迪康公司推广。它广泛应用于工业自动化，已成为实际的工业标准。该控制装置或不同厂家的测量仪器可以链接到一个行业监控网络使用Modbus 协议。Modbus 通信协议可以作为大量的工业设备的通讯标准，包括 PLC，DCS 系统，RTU 的，聪明的智能仪表。随着嵌入式计算机技术的飞速发展，嵌入式数据采集监测系统，使用了高性能的嵌入式微处理器为核心，是一个重要的发展方向。在环境鉴于嵌入式 Linux 的嵌入式工业自动化应用的数据，一个 Modbus 主协议下的采集监测系统的设计和实现了这个文件。因此，通信设备，各种药膏协议能够满足串行的 Modbus。

2、Modbus 协议简介

Modbus 协议包括 ASCII 码，RTU 和 TCP 传输模式，支持传统的 RS422，RSboot 的是先通过串口下载到开发板，然后使用串口或网络的方法。由于内核和文件系统的反映是相当大的文件，通过串行端口传输速度缓慢;以太网模式用于下载内核和文件系统。当然，网络的 Uboot 命令模式的 uboot：已编译的 Linux 可以操作臂后进行 bootm 21000000。内核和文件系统中内存可以通过闪存写入启动处长秩序的 u。该系统能自动运行后，设置启动参数。然后程序操作的开发板。

4.2、串行配置的 Modbus 协议在 Linux 环境下标准的 Modbus 串行协议使用的 RS232/RS485 传输。串行设备设备节点为/dev/ttyS0 来（COM1 端口）dev/ttyS1 COM2 端口）Linux 环境。和/（在由于 Modbus串行协议包括两种传输模式：ASCII 和 RTU 模式。起始标记和结束标记的两种模式是不同的。此外，每个信息包数据的位置也不同。因此，必须单独处理。以RTU 模式为例，介绍在 Linux 环境下的 Modbus 串行协议配置。头文件由串行操作需要的是：当 Modbus 协议的特点是采用 RTU 传输模式下，串行波特率，数据位，停止位置，检查位置和控制应根据设定的框架特征的信息。建立串口波特率：在设计中，以使其得到方便。功能参数，是一个结构的定义如下凡

slave_address 就是从站地址。一个 Modbus 网络允许最多 255 个从站。该函数是服务模式的选择特点，并有六种服务模式在本系统提供的，分别为 1-6。该 start_address 是 16 位字符，这是目前从站供电设备的起始地址。该pointnum_or_setdata 包括 2 种文字，服务 1-4 是点头人数增加经营，服务 5 和6 是 16 位字符正在建立。该方案首先确定了格式字符值，建立了传输模式，用户需要，这将决定哪些串行配置功能和服务功能什么样的选择。然后设置串口参数在 Linux 环境。相应的服务结构功能是通过判断用户的请求服务类型的选择。例如，如果格式为 0，采用 RTU 模式。该函数是 1，这意味着用户请求读取线圈。该方案通过使用 construct_rtu_frm 构造函数是rtu_read_status 函数调用的 Modbus 的请求帧。该方案保留了串行传输缓冲区mod_tx_buf，这是事先定义它，然后把通过调用命令的 Modbus 串行传输请求帧。如果程序设定的时间内得到答复框架，该方案将处理答复帧通过调用相应的模式解析函数。举例来说，当是 ASCII 传输模式，在 ascii_data_anlys 函数被调用，如果传输模式是 RTU 模式，然后

rtu_data_anlys 函数被调用。解析函数的分析数据，接收缓冲区接收串行。如果答复框架分析是正确的，该函数将数据加载到目标缓冲区。如果是错误的，该函数将终止这项服务，并处理错误，打印错误信息了。

4.3、Modbus 协议的串行软件设计

这里主要介绍了方案的设计与实现串行 Modbus 协议，其中包括两种传输模式

RTU 和 ASCII。在 Modbus 主机服务包括人机交互模块，功能选择模块，功能处理模块和返回处理模块。每个模块的功能是实现了在嵌入式 Linux 环境。人机交互模块是为用户和平台的通信模块。它主要实现了网页打印功能，用户信息的输入和指导等。该函数的选择模块是平台选择的 Modbus 主函数的选择参数根据用户输入的信息。这些参数包括传播方式的，服务类型，从站地址等。该函数处理模块是这个平台的核心。它包括串口初始化的功能，结构的Modbus 帧，模态分析的 Modbus 帧，各类业务处理和业务处理等 6 种主要的设计，其中包括：为串行的 Modbus 设备在这个平台阅读线圈状态，读输入状态，读保持寄存器，读输入寄存器，写，写单线圈单登记。这 6 种的模式涵盖了 Modbus的基本功能需求。而这是非常方便的扩大，如果必要的其他职能。返回处理模块流程操作平台的结果。如果用户请求的服务流程成功，服务结果将通过标准打印输出设备，否则错误信息打印。

4.4、服务的结构和功能分析框架

以读持有注册服务为例，介绍了施工过程中要求的 Modbus 帧。该函数读取保存寄存器数是 03 和建设要求的 Modbus 帧是实现通过 rtu_read_hldreg 和ascii_read_hldreg 功能。前者实现了 RTU 的框架结构，而后者的 ASCII 框架结构。该 rtu_read_hldreg 结构如下所示：输入参数 board_adr 就是从站地址，用户需要访问的。是缓冲区的 com_buf了 Modbus 帧传输领域。该 start_address 是访问的起始地址和长度 lenth 是访问的。所有这些变量，则是通过结构模块参数的人机互动。高（）和低（）是两个定义的函数。该高（）是为了获得高的 8 位，低（）是获得低 8 位。该 construct_rtu_frm 功能是 RTU 的框架结构。所有的服务都是通过调用此函数实现，形成 RTU 的请求帧。其结构如下所示：经过这些步骤，一帧请求已完成制作。最后，为了写（fd，mod_tx_buf，tx_len）是通过调用串行端口发送和传输缓冲区的请求的 Modbus 帧传输。tx_len 是服凡务构造函数返回值。请求帧传输后，该方案将等待从站回应。为了避免无休止的循环机制，通过检测从站没有回应，建立一个加班。如果从站并没有在预定时间响应，程序产生一个错误消息并停止该服务。如果服务程序在预定的时间收到答复框架，分析了通过调用

解析函数的答复时限。

5、结论

Modbus 通信协议的广泛使用，已成为事实上的工业标准，其实。它是用大量的工业设备作为它们之间的通讯标准，包括 DCS，可编程控制器，RTU 通讯，智能仪表及监控系统等新一代工业自动化数据采集采用高性能嵌入式微处理器为核心。因此，它适应应用程序很好地满足功能性，可靠性，成本，体积，功耗等严格要求，为了达到嵌入的数据监测的工业自动化应用，系统采集要求 Modbus协议的主站上的嵌入式数据采集监测 Linux 环境下的平台，是本文设计的基础。每个从站之间的通信实现。根据掌握的 Modbus 的嵌入式 Linux 环境服务程序运行稳定，可靠的测试后，Modbus 协议。它提供了良好服务的 Modbus 主站，并符合标准的 Modbus 协议。其在工业自动化数据采集监测系统的新一代应用前景非常好。

6、鸣谢

这项工作支持的项目一部分由上海科技攻关项目（编号 061111004），上海曙光跟踪计划（第 06GG13）和上海领先学科项目。

7、参考资料

[1] 第十一波，方艳 6 月应用嵌入在串口设备联网技术[J]。电力自动化设备，2007，27（8）99-101。

[2] 张浩，黄云彦，彭道岗。EGI 立足于预警系统研究[J] Modbus 协议。机电一体化，2007，13（2）:15

8。

[3] 李娟，张波，丘东元。多机通信与 Modbus RTU 的总部设在电能质量监测系统[J]。电力自动化

设备，2007，27，（1）:9310。

[5] 闵华松，刘光临。嵌入式状态监测与故障诊断系统的高速旋转机械的研究[J]。信息与控制，2006,35

（3）：309-313。

[6] 鲍可进，邬建勇。对权力的执行情况与嵌入式 Web 服务器系统[J]远程监控。计算机工程与设计，2007,28（13）：3178-3180。

第二篇：运筹学论文中英文翻译

A maximum flow formulation of a multi-period open-pit

mining problem 多期露天采矿的最大流公式

Henry Amankwah • Torbjo¨rn Larsson • Bjo¨rn Textorius

Abstract 摘要

We consider the problem of finding an optimal mining sequence for an open pit during a number of time periods subject to only spatial and temporal precedence constraints.This problem is of interest because such constraints are generic to any open-pit scheduling problem and, in particular, because it arises as a Lagrangean relaxation of an open-pit scheduling problem.We show that this multi-period open-pit mining problem can be solved as a maximum flow problem in a time-expanded mine graph.Further, the minimum cut in this graph will define an optimal sequence of pits.This result extends a well-known result of J.-C.Picard from 1976 for the open-pit mine design problem, that is, the single-period case, to the case of multiple time periods.我们认为在若干期间，找到一个最佳的露天采矿的开采顺序，只会受到空间和时间的优先约束。这个问题很有趣，因为这些约束通用于任何露天矿调度问题，特别是因为它是作为露天矿调度的拉格朗日松弛算法而出现的。我们可以将这种多期露天开采的问题作为一个时间扩张矿图的最大流问题来解决。此外，本图中的最小割集将定义的矿坑的最佳顺序。这个结果是J.C.Picard著名理论的延伸，J.C.Picard从1976年就研究露天矿设计问题，即，单周期的情况下，对多个时间段的研究。Introduction

Open-pit mining is a surface mining operation whereby ore, or waste, is excavated from the surface of the land, and in so doing a deeper and deeper pit is formed.Before the mining begins, the volume of the ore deposit is usually partitioned into blocks and the value of the ore in each block is estimated by using geological information from drill holes.The cost of mining and processing each block is also estimated.A profit can thus be assigned to each block of the mine model, as illustrated in Fig.1 引言

露天开采是一个表面采矿作业，从地面挖掘出矿石或废物，因此形成一个越来越深的坑。在开始采矿前，通常把矿床划分成块，通过钻孔的地质信息估计每块矿床的价值。每块矿床的开采和加工成本也能估计。利润可以分配给每个矿山 模型，如图所示。

A fundamental problem in open-pit mine planning is to decide which blocks to mine.This is known as the problem of finding an open-pit mine design, or an ultimate contour for the pit.The only restrictions are spatial precedence relationships, stating that in order to extract any given block, so must all blocks immediately above and within a required wall slope angle.Lerchs and Grossmann(1965)showed that the design problem can be stated as the problem of finding a maximal closure in a mine graph which represents the blocks and the precedence restrictions, as shown in Fig.1(for a safe slope angle of 45).Their algorithm for finding a maximal closure in the mine graph has over the years been commonly used by the mining industry for the design of open pits.在露天矿山规划中，一个基本问题是决定开采哪块矿。这被称为寻找露天矿山设计的问题，或矿井的最终轮廓问题。唯一的限制是空间优先的关系，指出为了提取任何给定的矿块，所有矿块必须在上面和在要求的壁面收敛角范围内。勒奇斯和格罗斯曼（1965）表明，设计问题可以表述为在矿图中寻找最大闭合的问题，这幅矿图能表现矿块和优先级限制，如图1所示（45°的安全坡度）。多年来，他们用来在矿图中寻找最大闭合的公式，在采矿业的露天矿设计中也被普遍使用。

The practical significance of the open-pit mine design problem makes it an important instance of the maximal closure problem(Picard and Queyranne, 1982).As shown by Picard(1976), the problem of finding a maximal closure in a mine graph can be solved as a maximum flow problem in a network derived from the mine graph, and where a minimum cut determines an optimal pit contour.Later, Hochbaum and Chen(2000)and Hochbaum(2001)developed efficient maximum flow algorithms for the open-pit mining problem.露天矿设计问题的实际意义是使其成为最大闭合问题中的一个重要实例（皮卡德和凯拉纳，1982）。皮卡德（1976）表明，在矿图中寻找最大闭合的问题

可以作为矿图中网状图的最大流问题来解决，矿图中，最小割集确定最佳矿井轮廓。后来，陈（2000）和霍赫鲍姆（2001）研究出高效的露天开采的最大流算法。

In reality, the profit of a block depends on when it is mined, for example due to discounting.This fact leads to another crucial issue in open-pit mine planning, namely scheduling.This is the process of deciding how and when to mine the blocks so as to maximize profit(typically the net present value), while obeying the wall slope and precedence constraints, as well as various mining capacity restrictions.Contributions within open-pit mine scheduling, from the view of mathematical optimization, have been given by Gershon(1983), Dagdelen and Johnson(1986), Caccetta and Hill(2003), Ramazan(2007), Rafiee and Asghari(2008), Bley et al.(2010), and Cullenbine et al.(2011), among others.在现实中，一个矿块的利润取决于开采时，例如由于打折。这个事实导致了露天矿山规划的另一个关键问题，即调度。这是决定何时开采、如何开采并使利润最大化（通常是净现值）的过程，同时遵守墙坡和优先约束，并受到各种开采能力的限制。Gershon(1983), Dagdelen 和 Johnson(1986), Caccetta和Hill(2003), Ramazan(2007), Rafiee和Asghari(2008), Bley et al.Cullenbineetal(2011)等人已经从数学优化的角度给出了露天矿山调度的贡献。

We consider a multi-period open-pit mining problem with only spatial and temporal precedence constraints.The latter simply state that once a block has been mined, it shall remain mined.The spatial and temporal precedence constraints are generic to open-pit mine scheduling and the multi-period problem arises as a Lagrangean relaxed open-pit scheduling problem, when capacity restrictions are Lagrangean dualized.我们只考虑有空间和时间优先约束的多周期的露天开采问题。后者简单阐明，一旦矿块被开采，应当继续开采。空间和时间的优先约束通用于露天矿调度和多周期问题，它作为拉格朗日松弛的露天作业调度问题而出现，此时能力限制符合拉格朗日对偶。

It will be shown that this multi-period open-pit mining problem can be formulated as a maximum flow problem in a time-expanded mine graph, which has a copy of the mine graph for each time period.The expanded graph also contains directed arcs that model the temporal precedence relationships between the corresponding nodes in successive copies of the mine graph;these arcs are analogous to those that model the spatial precedence relationships within each of the mine graphs.This maximum flow formulation extends the result of Picard(1976)to the case of multiple time periods.Figure 2 shows the time-expansion of the mine graph in Fig.1, for the case T = 3.可以表明，这个多期露天开采问题是可以当作时间扩张矿图中的最大流问题，时间扩张矿图中含有每个时期的矿图副本。扩张图还包含模仿矿图连续副本中相应节点间暂时优先关系的有向弧，这些弧与每幅矿图中模仿空间优先级关系的弧是相似的。这个最大流量公式是皮卡尔（1976）对于多期研究结果的扩展。图2显示了图1中矿图的时间扩展，此时T = 3。

In Sect.2 we give the mathematical model of the problem considered.In Sect.3 we present the maximum flow problem in the time-expanded mine graph and show that a minimum cut in this graph defines an optimal solution to the multi-period

第2部分给出了数学模型。第3部分呈现了时间扩张矿图中的最大流问题，并且表明，本图的最小割集定义了多期问题的最优解。

Fig.1 A 2-D block model of a mine with block profit values and its mine graph 图1

一个带有利润价值及矿图的矿块模型

Fig.2 A time-expanded mine graph with three time periods open-pit mining problem.Section 4 presents a small illustrative example.The last section gives a couple of concluding remarks.图2 三个时间段露天开采问题时间扩张矿图。

第4部分给出了一个小例子。最后一部分节给出了结束语。The mathematical model 数学模型

The following notation will be used.将使用到下面的符号。

T

number of time periods.时间段的数量

V

set of all blocks that can be mined.可以开采的矿块集合

A

set of pairs(i, j)of blocks such that block j is a neighbouring block to i that must be removed before block i can be mined.矿块(i, j)的集合，矿块j与矿块i 相邻的矿块，要想开采矿块i，必须先移除矿块j contribution to the objective value if block i is mined in time period t or earlier，如果在时间段t 或早些时候开采矿块i，对于客观价值的贡献

Defining the decision variables for all对于所有的，定义决策变量

if block i is mined in time period t or earlier如果在时间段t 或早些时候开采矿块i

0

Otherwise

其他情况 the multi-period open-pit mining problem is formulated as 多期露天矿山开采问题可表述为

subject to 满足

The first and second sets of constraints are spatial respective temporal precedence restrictions.As shall be shown, an optimal solution to this problem is found by solving a maximum flow problem in the time-expanded mine graph.第一个和第二个约束集合是各个空间暂时的优先限制。正如所表明的一样，通过求解时间扩张矿图中的最大流问题，找到这一问题的最优解。The maximum flow formulation最大流公式

In order to state the time-expanded maximum flow problem, we introduce the sets of block nodes

and

and further letandbe the source and sink nodes respectively of the network, which includes arcs from the source node to the nodesnodes

to the sink node.Lettingthe maximum flow problem is as follows.and arcs from the

and

subject to

为了陈述时间扩张的最大流问题，我们引入矿块结点的集合和络的源结点和汇聚结点，包括从源结点到结点到汇聚结点的弧。让，最大流问题如下。，进一步让和成为各个网的弧，从结点

并且

满足

Here, f is the total flow, the quantityin time period t, and each

is the flow from block node i to block node j

corresponds to a forward arc between corresponding

is the flow from the source node block nodes in successive time periods.Further,to block node i in period t, while

is the flow from block node i in period t to the sink node.An example of the maximum flow network is given in Fig.3, with 9 blocks and 3 time periods(but with only some of the arcs shown).这里，f是总流量，分量

是在时间段t内从结点i到结点j的流量，每个

对应一个连续时间段内对应矿块结点之间的正向弧。此外，源结点到矿块结点i的流量，是在时间段 t内从

在时间段 t内从矿块结点i到汇聚结点的流量。图3给出了一个最大流量网络的例子，图中有9个矿块和3个时间段（但是只表示了部分弧）。

Letbe a minimum cut in the time-expanded maximum flow network.Then

andthrough the mine graph copy for time period t.让成为时间扩张最大流网络中的最小割集。那么，图副本的割集。

Theorem 1 An optimal solution to Problem(1)is given by

是通过时间段t的矿where

is the cut

And

Proof

We study the linear programming dual of the above maximum flow problem.Letblock nodes in the network, and letassociated introducingwith

the

source

and

be the dual variables corresponding to the

be the respective dual variables the

sink.By

further

as the dual variables for the upper bound constraints, the dual problem becomes

subject to

An optimal solution to the dual problem is then(e.g., Bazaraa and Jarvis 1977)given by

理论一

问

题

(1)的最优解为

并且

证明

我们学习了上述最大流问题的对偶线性规划。让成为和网络图中的矿块结点相一致的对偶变量，让和汇聚结点相关联的对偶变量。通过进一步引入偶变量是上界约束，对偶问题变为

成为分别与源结点，由于对满足

(例如., Bazaraa 和 Jarvis 1977)给出对偶问题的最优解

Fig.3 Example of the maximum flow network(with sample arcs)图3 最大流网络图实例（样本弧）And 并且

Then, for

那么，对于

and for

对于

It then holds that 然后，得到

subject to the constraints(3)–(8)and to 满足限制条件(3)–(8)并使

with the optimal solution to Problem(2)still being optimal, since restrictingandto their respective optimal values and enforcing the equalities(9)and(10)to hold for any solutions will not affect its optimality.对于问题（2）来说，最优解仍然是最佳的，因为和r局限于各自的最佳值并且执行等式（9）和（10）以保证任何解都不会影响其最优性。

As is easily verified, constraints(3)–(5)can be removed from Problem(11), since they will always be fulfilled.By further eliminating the variables,and

from Problem(11)it is reduced to

很容易验证，限制条件（3）–（5）可以从问题（11）中去除，因为它们一直被满足。通过进一步从问题（11）中消除变量它减小为 ,和，subject to 满足

Now, letproblem can be stated as 现在，对于所有的问题可以陈述为

让

然后，上述

for all

Then the above

subject to满足

which is solved by 得到

Since this optimal solution is binary, it follows that it is also an optimal solution to Problem(1).The expression for its optimal value follows directly from the above objective function.因为这个最优解是二元的，因此，它也是问题（1）的最优解。其最佳值的表达式直接符合上面的目标函数。

Since the forward arcs corresponding to the variablesfollows thatwhenever

so that

are not capacitated, it

holds.Hence, the sequence of cutsdefine larger and larger pits.The blocks mined precisely in the first time period are those corresponding to the nodes in the set the sets由于与变量得到while for t =2,...,Tit is the blocks corresponding to the nodes in

相应的向前弧是非限量的，它符合当

。因此，割集序列

时，所以，定

中的结点，当t 义越来越大的矿坑。在第一时间段，精确开采的矿块对应集合=2,...,时，Tit就是与集合

中的结点相对应的矿块。An example

As mentioned in the introduction, the problem under consideration is of interest because it appears when an open-pit mine scheduling problem is Lagrangean relaxed.To illustrate this, we consider the following scheduling model, which is a special case of the model considered by Bley et al.(2010).4 例子

简介中提到，我们所考虑的问题很有趣，因为当露天矿山的调度问题是拉格朗日轻松时，它才出现。为了说明这一点，我们考虑以下的调度模型，布莱等人认为这是此模型的特殊情况（2010）。

subject to 满足

The decision variables

are

defined

as

above.(Note

that

the differenceperiod t).Further,takes the value one when block i is mined in exactly time is the profit made from mining block i in time period t,is the tonnage of block i, andLetting

is an upper bound on the tonnage mined in time period t.be multipliers associated with the constraints on maximal tonnage mined in each time period and Lagrangean relaxing these constraints, we obtain an instance of Problem(1), with the coefficients in the objective function being the Lagrangean reduced profits

决策变量的定义同上。（注意，当矿块 i正好在时间段t开采时，差值为1）。此外，的吨位，是在时间段t开采矿块 i时获得的利润，是矿块 i是时间段t的一个上限吨位。让 作为与每个时间段内最大吨位约束相关联的乘数，拉格朗日松弛这些限制，我们得到问题（1）的一个实例，目标函数的系数成为拉格朗日下降利润。

The reader may note that Problem(1)would also arise as a column generation problem(or, pricing problem)if the linear programming relaxation of Problem(12)is solved by a column generation scheme.读者可能会注意到，如果问题（12）的线性规划松弛是通过一个列生成方案解决的话，问题（1）也将作为一个列生成问题出现（或者，定价问题）。

To illustrate the result of the theorem, we consider the block model in Fig.1 and construct an instance of Problem(12)by lettingand

for all t, for all i.Further, the profit values are discounted by a factor 0.90 for each time period.To create an instance of Problem(1)we Lagrangean relax the Capacity constraints with the multiplier values

Fig.4 Minimum cut that defines the mining sequence

图4 定义挖掘顺序的最小割集

and[These values come from the dual of the linear programming relaxation of Problem(12)].The minimum cut for the time-expanded maximum flow problem is shown in Fig.4.It indicates that blocks 2 and 3 are mined in the first time period, blocks 4 and 6 in the second, and blocks 1 and 5 in the last.The optimal profit is 12.21.为了说明该定理的结果，我们考虑到图1中的模型，通过让所有的t满足，让所有的 i满足

构造问题（12）的一个实例。而且，利润值被每个时间段的系数0.90所折扣。为了创建问题（1）的一个实例，我们 将能力约束与乘数值

进行拉格朗日松弛。[这些数值来自于问题（12）的线性规划松弛的对偶]。时间扩张最大流问题的最小割集如图4所示。结果表明，矿块2和矿3是在第一时间段开采的，矿块4和矿块6在第二时间段开采的，矿块1和矿块5是在最后一个时间段开采的。最优利润是12.21。Conclusion

We have given a maximum flow formulation of a multi-period open-pit mining problem.It extends the classic maximum flow formulation of Picard(1976)for a single time period by means of a time-expanded network.Picard’s derivation is based on a reformulation of the open-pit mine design problem into a quadratic binary program, while our proof of the validity of the time-expanded maximum flow formulation is based on linear programming duality.5

结论

我们已经给出了多期露天开采的最大流量公式。它扩充了皮卡尔(1976)经典的最大流公式，该公式借助时间扩张网络，针对单一时间段进行研究。皮卡尔的推导基于将露天矿山设计问题转化为一个二次二进制程序的再形成，基于线性规划对偶，我们正确证明了时间扩张最大流。

The problem under consideration in this paper arises naturally if all constraints of an open-pit scheduling problem but the spatial and temporal precedence restrictions are Lagrangean dualized, or priced out in a column generation fashion.For any values of the Lagrangean multipliers, the maximum flow solution in the time expanded network will correspond to a mining schedule that is feasible with respect to both the spatial and temporal precedence restrictions.The Lagrangean multipliers can then be thought of as parameters that shall be tuned such that the capacity restrictions become fulfilled, in an optimal way.Because of the prevalence of a duality gap, this strategy cannot however be expected to be sufficient to optimally solve the scheduling problem.本文中所考虑的问题是自然产生的，如果除空间和时间约束条件外，所有的 露天矿山的调度问题都是拉格朗日对偶，或被排出列生成。对于拉格朗日因子的任何值，在时间扩张网络图中的最大流的解对应一个对于空间和时间优先限制都可行的采掘计划。拉格朗日因子可以被认作应调整的参数，这样以最佳的方式实现能力限制。因为普遍存在对偶间隙，这种策略不能最好地解决调度问题。

Opportunities for further research are clearly the study of Lagrangean dual and column generation approaches based on the time-expanded maximum flow problem,as a vehicle for solving open-pit mine scheduling problems, heuristically or optimally.很明显，进一步的研究机会是基于时间扩张最大流问题的拉格朗日对偶和列生成方法的研究，作为启发式地或最佳地解决露天矿山调度问题的工具。

第三篇：机械中英文翻译论文题目

专做机械类毕业设计，可代画CAD、PROE图 有需要可联系Q Q3590003551、Calypso2、Calypso13、HOLONIC生产系统的产品设计

4、标准化在塑料注射模具初始化设计中的应用

5、不规则制造系统的动态代理人模型和说明书

6、常规压力对采用非牛顿学流体润滑的光滑碟片表面的作用

7、超精密加工与超高速加工技术

8、车床及其切削加工

9、车削、铣削和磨削

10、冲压变形

11、淬硬齿轮的加工

12、刀具成本的检测

13、对振动侦查和测量的一种实用方法-物理原则和侦查技术

14、发展“机电一体化”的思路和对策

15、反求工程

16、非开挖技术在电力工程中的应用

17、废旧轮胎资源综合利用技术

18、分析一组协作移动机械手

19、高速切削加工在模具制造中的应用

20、机床实践

21、机器人传感器的网络

22、机器人技术发展趋势

23、机器人介绍

24、机械加工表面质量

25、机械零件的强度和计算机与制造业

26、机械零配件中圆柱表面的智能定位

27、机械设计基础

28、基于代理的模型为处理综合产品信息

29、基于快速原形制造的综合应用

30、基于快速原型的综合制造

31、基于事例推理的夹具设计研究与应用

32、基于网络的快速原型制造

33、计算机辅助过程规划管理信息基础薄板

34、浇铸钛和金的显微结构和机械性能

35、快速成型技术和系统的回顾

36、快速原形机的软件补偿

37、快速原型技术及在模具制造中的应用

38、宽槽圆柱凸轮数控加工技术的研究

39、蜡模精确成型在浇注中的实验性研究

40、冷锻技术的发展现状与趋势

41、利用三坐标测量仪确定聚苯乙烯材料表面形态

42、模具快速制造技术的发展方向

43、破碎粉磨设备的磨损与耐磨材料的发展

44、汽车零件加工中的环保技术

45、切削侧表面刀具的磨损高速干切削

46、认识曲柄摇臂机构设计的最优传动方法

47、柔性制造系统

48、润滑和摩擦学在海水水力活塞泵中的应用

49、生产胶粉—废旧轮胎回收利用的方向

50、事例研究—反求工程零部件的远程制造

51、数控技术和装备发展趋势及对策

52、数控技术和装备发展趋势及对策153、数字控制

54、铁金属及其合金

55、先进制造技术的新发展

56、现代集成制造技术

57、现代集成制造系统的技术构成及发展策略研究

58、现代制造业中计算机的应用

59、虚拟制造的机械加工过程仿真

60、虚拟制造技术及其应用

61、选域激光熔解法在钛模快速原型加工中的作用

62、研磨机的最佳优化设计

63引线键合的现状与发展趋势

64、影响切割工艺的材料属性的总体

65、在干和湿的高速加工环境下表面涂上碳化物和不涂碳化物对产品生命周期的影响

66、在干燥和潮湿的条件下研究高速切削的费用以及便于机械制造过程的优化

67、在高速潮湿机械加工条件下后刀面表层磨损机理

68、在高速干加工条件下含有TIALN涂层的插入物磨损机理的实验性观察

69、制造业为产品设计花费模型

第四篇：中英文翻译

Fundamentals This chapter describes the fundamentals of today’s wireless communications.First a detailed description of the radio channel and its modeling are presented, followed by the introduction of the principle of OFDM multi-carrier transmission.In addition, a general overview of the spread spectrum technique, especially DS-CDMA, is given and examples of potential applications for OFDM and DS-CDMA are analyzed.This introduction is essential for a better understanding of the idea behind the combination of OFDM with the spread spectrum technique, which is briefly introduced in the last part of this chapter.1.1 Radio Channel Characteristics Understanding the characteristics of the communications medium is crucial for the appropriate selection of transmission system architecture, dimensioning of its components, and optimizing system parameters, especially since mobile radio channels are considered to be the most difficult channels, since they suffer from many imperfections like multipath fading, interference, Doppler shift, and shadowing.The choice of system components is totally different if, for instance, multipath propagation with long echoes dominates the radio propagation.Therefore, an accurate channel model describing the behavior of radio wave propagation in different environments such as mobile/fixed and indoor/outdoor is needed.This may allow one, through simulations, to estimate and validate the performance of a given transmission scheme in its several design phases.1.1.1 Understanding Radio Channels In mobile radio channels(see Figure 1-1), the transmitted signal suffers from different effects, which are characterized as follows: Multipath propagation occurs as a consequence of reflections, scattering, and diffraction of the transmitted electromagnetic wave at natural and man-made objects.Thus, at the receiver antenna, a multitude of waves arrives from many different directions with different delays, attenuations, and phases.The superposition of these waves results in amplitude and phase variations of the composite received signal.Doppler spread is caused by moving objects in the mobile radio channel.Changes in the phases and amplitudes of the arriving waves occur which lead to time-variant multipath propagation.Even small movements on the order of the wavelength may result in a totally different wave superposition.The varying signal strength due to time-variant multipath propagation is referred to as fast fading.Shadowing is caused by obstruction of the transmitted waves by, e.g., hills, buildings, walls, and trees, which results in more or less strong attenuation of the signal strength.Compared to fast fading, longer distances have to be covered to significantly change the shadowing constellation.The varying signal strength due to shadowing is called slow fading and can be described by a log-normal distribution [36].Path loss indicates how the mean signal power decays with distance between transmitter and receiver.In free space, the mean signal power decreases with the square of the distance between base station(BS)and terminal station(TS).In a mobile radio channel, where often no line of sight(LOS)path exists, signal power decreases with a power higher than two and is typically in the order of three to five.Variations of the received power due to shadowing and path loss can be efficiently counteracted by power control.In the following, the mobile radio channel is described with respect to its fast fading characteristic.1.1.2 Channel Modeling The mobile radio channel can be characterized by the time-variant channel impulse response h(τ , t)or by the time-variant channel transfer function H(f, t), which is the Fourier transform of h(τ , t).The channel impulse response represents the response of the channel at time t due to an impulse applied at time t − τ.The mobile radio channel is assumed to be a wide-sense stationary random process, i.e., the channel has a fading statistic that remains constant over short periods of time or small spatial distances.In environments with multipath propagation, the channel impulse response is composed of a large number of scattered impulses received over Np different paths，Where

and ap, fD,p, ϕp, and τp are the amplitude, the Doppler frequency, the phase, and the propagation delay, respectively, associated with path p, p = 0,..., Np − 1.The assigned channel transfer function is

The delays are measured relative to the first detectable path at the receiver.The Doppler Frequency

depends on the velocity v of the terminal station, the speed of light c, the carrier frequency fc, and the angle of incidence αp of a wave assigned to path p.A channel impulse response with corresponding channel transfer function is illustrated in Figure 1-2.The delay power density spectrum ρ(τ)that characterizes the frequency selectivity of the mobile radio channel gives the average power of the channel output as a function of the delay τ.The mean delay τ , the root mean square(RMS)delay spread τRMS and the maximum delay τmax are characteristic parameters of the delay power density spectrum.The mean delay is

Where

Figure 1-2 Time-variant channel impulse response and channel transfer function with frequency-selective fading is the power of path p.The RMS delay spread is defined as Similarly, the Doppler power density spectrum S(fD)can be defined that characterizes the time variance of the mobile radio channel and gives the average power of the channel output as a function of the Doppler frequency fD.The frequency dispersive properties of multipath channels are most commonly quantified by the maximum occurring Doppler frequency fDmax and the Doppler spread fDspread.The Doppler spread is the bandwidth of the Doppler power density spectrum and can take on values up to two times |fDmax|, i.e.，1.1.3Channel Fade Statistics The statistics of the fading process characterize the channel and are of importance for channel model parameter specifications.A simple and often used approach is obtained from the assumption that there is a large number of scatterers in the channel that contribute to the signal at the receiver side.The application of the central limit theorem leads to a complex-valued Gaussian process for the channel impulse response.In the absence of line of sight(LOS)or a dominant component, the process is zero-mean.The magnitude of the corresponding channel transfer function

is a random variable, for brevity denoted by a, with a Rayleigh distribution given by

Where

is the average power.The phase is uniformly distributed in the interval [0, 2π].In the case that the multipath channel contains a LOS or dominant component in addition to the randomly moving scatterers, the channel impulse response can no longer be modeled as zero-mean.Under the assumption of a complex-valued Gaussian process for the channel impulse response, the magnitude a of the channel transfer function has a Rice distribution given by

The Rice factor KRice is determined by the ratio of the power of the dominant path to thepower of the scattered paths.I0 is the zero-order modified Bessel function of first kind.The phase is uniformly distributed in the interval [0, 2π].1.1.4Inter-Symbol(ISI)and Inter-Channel Interference(ICI)The delay spread can cause inter-symbol interference(ISI)when adjacent data symbols overlap and interfere with each other due to different delays on different propagation paths.The number of interfering symbols in a single-carrier modulated system is given by

For high data rate applications with very short symbol duration Td < τmax, the effect of ISI and, with that, the receiver complexity can increase significantly.The effect of ISI can be counteracted by different measures such as time or frequency domain equalization.In spread spectrum systems, rake receivers with several arms are used to reduce the effect of ISI by exploiting the multipath diversity such that individual arms are adapted to different propagation paths.If the duration of the transmitted symbol is significantly larger than the maximum delay Td τmax, the channel produces a negligible amount of ISI.This effect is exploited with multi-carrier transmission where the duration per transmitted symbol increases with the number of sub-carriers Nc and, hence, the amount of ISI decreases.The number of interfering symbols in a multi-carrier modulated system is given by

Residual ISI can be eliminated by the use of a guard interval(see Section 1.2).The maximum Doppler spread in mobile radio applications using single-carrier modulation is typically much less than the distance between adjacent channels, such that the effect of interference on adjacent channels due to Doppler spread is not a problem for single-carrier modulated systems.For multi-carrier modulated systems, the sub-channel spacing Fs can become quite small, such that Doppler effects can cause significant ICI.As long as all sub-carriers are affected by a common Doppler shift fD, this Doppler shift can be compensated for in the receiver and ICI can be avoided.However, if Doppler spread in the order of several percent of the sub-carrier spacing occurs, ICI may degrade the system performance significantly.To avoid performance degradations due to ICI or more complex receivers with ICI equalization, the sub-carrier spacing Fs should be chosen as

such that the effects due to Doppler spread can be neglected(see Chapter 4).This approach corresponds with the philosophy of OFDM described in Section 1.2 and is followed in current OFDM-based wireless standards.Nevertheless, if a multi-carrier system design is chosen such that the Doppler spread is in the order of the sub-carrier spacing or higher, a rake receiver in the frequency domain can be used [22].With the frequency domain rake receiver each branch of the rake resolves a different Doppler frequency.1.1.5Examples of Discrete Multipath Channel Models Various discrete multipath channel models for indoor and outdoor cellular systems with different cell sizes have been specified.These channel models define the statistics of the 5 discrete propagation paths.An overview of widely used discrete multipath channel models is given in the following.COST 207 [8]: The COST 207 channel models specify four outdoor macro cell propagation scenarios by continuous, exponentially decreasing delay power density spectra.Implementations of these power density spectra by discrete taps are given by using up to 12 taps.Examples for settings with 6 taps are listed in Table 1-1.In this table for several propagation environments the corresponding path delay and power profiles are given.Hilly terrain causes the longest echoes.The classical Doppler spectrum with uniformly distributed angles of arrival of the paths can be used for all taps for simplicity.Optionally, different Doppler spectra are defined for the individual taps in [8].The COST 207 channel models are based on channel measurements with a bandwidth of 8–10 MHz in the 900-MHz band used for 2G systems such as GSM.COST 231 [9] and COST 259 [10]: These COST actions which are the continuation of COST 207 extend the channel characterization to DCS 1800, DECT, HIPERLAN and UMTS channels, taking into account macro, micro, and pico cell scenarios.Channel models with spatial resolution have been defined in COST 259.The spatial component is introduced by the definition of several clusters with local scatterers, which are located in a circle around the base station.Three types of channel models are defined.The macro cell type has cell sizes from 500 m up to 5000 m and a carrier frequency of 900 MHz or 1.8 GHz.The micro cell type is defined for cell sizes of about 300 m and a carrier frequency of 1.2 GHz or 5 GHz.The pico cell type represents an indoor channel model with cell sizes smaller than 100 m in industrial buildings and in the order of 10 m in an office.The carrier frequency is 2.5 GHz or 24 GHz.COST 273: The COST 273 action additionally takes multi-antenna channel models into account, which are not covered by the previous COST actions.CODIT [7]: These channel models define typical outdoor and indoor propagation scenarios for macro, micro, and pico cells.The fading characteristics of the various propagation environments are specified by the parameters of the Nakagami-m distribution.Every environment is defined in terms of a number of scatterers which can take on values up to 20.Some channel models consider also the angular distribution of the scatterers.They have been developed for the investigation of 3G system proposals.Macro cell channel type models have been developed for carrier frequencies around 900 MHz with 7 MHz bandwidth.The micro and pico cell channel type models have been developed for carrier frequencies between 1.8 GHz and 2 GHz.The bandwidths of the measurements are in the range of 10–100 MHz for macro cells and around 100 MHz for pico cells.JTC [28]: The JTC channel models define indoor and outdoor scenarios by specifying 3 to 10 discrete taps per scenario.The channel models are designed to be applicable for wideband digital mobile radio systems anticipated as candidates for the PCS(Personal Communications Systems)common air interface at carrier frequencies of about 2 GHz.UMTS/UTRA [18][44]: Test propagation scenarios have been defined for UMTS and UTRA system proposals which are developed for frequencies around 2 GHz.The modeling of the multipath propagation corresponds to that used by the COST 207 channel models.HIPERLAN/2 [33]: Five typical indoor propagation scenarios for wireless LANs in the 5 GHz frequency band have been defined.Each scenario is described by 18discrete taps of the delay power density spectrum.The time variance of the channel(Doppler spread)is modeled by a classical Jake’s spectrum with a maximum terminal speed of 3 m/h.Further channel models exist which are, for instance, given in [16].1.1.6Multi-Carrier Channel Modeling Multi-carrier systems can either be simulated in the time domain or, more computationally efficient, in the frequency domain.Preconditions for the frequency domain implementation are the absence of ISI and ICI, the frequency nonselective fading per sub-carrier, and the time-invariance during one OFDM symbol.A proper system design approximately fulfills these preconditions.The discrete channel transfer function adapted to multi-carrier signals results in

where the continuous channel transfer function H(f, t)is sampled in time at OFDM symbol rate s and in frequency at sub-carrier spacing Fs.The duration

s is the total OFDM symbol duration including the guard interval.Finally, a symbol transmitted onsub-channel n of the OFDM symbol i is multiplied by the resulting fading amplitude an,i and rotated by a random phase ϕn,i.The advantage of the frequency domain channel model is that the IFFT and FFT operation for OFDM and inverse OFDM can be avoided and the fading operation results in one complex-valued multiplication per sub-carrier.The discrete multipath channel models introduced in Section 1.1.5 can directly be applied to(1.16).A further simplification of the channel modeling for multi-carrier systems is given by using the so-called uncorrelated fading channel models.1.1.6.1Uncorrelated Fading Channel Models for Multi-Carrier Systems These channel models are based on the assumption that the fading on adjacent data symbols after inverse OFDM and de-interleaving can be considered as uncorrelated [29].This assumption holds when, e.g., a frequency and time interleaver with sufficient interleaving depth is applied.The fading amplitude an,i is chosen from a distribution p(a)according to the considered cell type and the random phase ϕn,I is uniformly distributed in the interval [0,2π].The resulting complex-valued channel fading coefficient is thus generated independently for each sub-carrier and OFDM symbol.For a propagation scenario in a macro cell without LOS, the fading amplitude an,i is generated by a Rayleigh distribution and the channel model is referred to as an uncorrelated Rayleigh fading channel.For smaller cells where often a dominant propagation component occurs, the fading amplitude is chosen from a Rice distribution.The advantages of the uncorrelated fading channel models for multi-carrier systems are their simple implementation in the frequency domain and the simple reproducibility of the simulation results.1.1.7Diversity The coherence bandwidth of a mobile radio channel is the bandwidth over which the signal propagation characteristics are correlated and it can be approximated by

The channel is frequency-selective if the signal bandwidth B is larger than the coherence bandwidth.On the other hand, if B is smaller than , the channel is frequency nonselective or flat.The coherence bandwidth of the channel is of importance for evaluating the performance of spreading and frequency interleaving techniques that try to exploit the inherent frequency diversity Df of the mobile radio channel.In the case of multi-carrier transmission, frequency diversity is exploited if the separation of sub-carriers transmitting the same information exceeds the coherence bandwidth.The maximum achievable frequency diversity Df is given by the ratio between the signal bandwidth B and the coherence bandwidth，The coherence time of the channel is the duration over which the channel characteristics can be considered as time-invariant and can be approximated by

If the duration of the transmitted symbol is larger than the coherence time, the channel is time-selective.On the other hand, if the symbol duration is smaller than , the channel is time nonselective during one symbol duration.The coherence time of the channel is of importance for evaluating the performance of coding and interleaving techniques that try to exploit the inherent time diversity DO of the mobile radio channel.Time diversity can be exploited if the separation between time slots carrying the same information exceeds the coherence time.A number of Ns successive time slots create a time frame of duration Tfr.The maximum time diversity Dt achievable in one time frame is given by the ratio between the duration of a time frame and the coherence time, A system exploiting frequency and time diversity can achieve the overall diversity

The system design should allow one to optimally exploit the available diversity DO.For instance, in systems with multi-carrier transmission the same information should be transmitted on different sub-carriers and in different time slots, achieving uncorrelated faded replicas of the information in both dimensions.Uncoded multi-carrier systems with flat fading per sub-channel and time-invariance during one symbol cannot exploit diversity and have a poor performance in time and frequency selective fading channels.Additional methods have to be applied to exploit diversity.One approach is the use of data spreading where each data symbol is spread by a spreading code of length L.This, in combination with interleaving, can achieve performance results which are given for

by the closed-form solution for the BER for diversity reception in Rayleigh fading channels according to [40]

Whererepresents the combinatory function，and σ2 is the variance of the noise.As soon as the interleaving is not perfect or the diversity offered by the channel is smaller than the spreading code length L, or MCCDMA with multiple access interference is applied,(1.22)is a lower bound.For L = 1, the performance of an OFDM system without forward error correction(FEC)is obtained, 9

which cannot exploit any diversity.The BER according to(1.22)of an OFDM(OFDMA, MC-TDMA)system and a multi-carrier spread spectrum(MC-SS)system with different spreading code lengths L is shown in Figure 1-3.No other diversity techniques are applied.QPSK modulation is used for symbol mapping.The mobile radio channel is modeled as uncorrelated Rayleigh fading channel(see Section 1.1.6).As these curves show, for large values of L, the performance of MC-SS systems approaches that of an AWGN channel.Another form of achieving diversity in OFDM systems is channel coding by FEC, where the information of each data bit is spread over several code bits.Additional to the diversity gain in fading channels, a coding gain can be obtained due to the selection of appropriate coding and decoding algorithms.中文翻译 1基本原理

这章描述今日的基本面的无线通信。第一一个的详细说明无线电频道，它的模型被介绍，跟随附近的的介绍的原则的参考正交频分复用多载波传输。此外，一个一般概观的扩频技术，尤其ds-cdma，被给，潜力的例子申请参考正交频分复用，DS对1。分配的通道传输功能是

有关的延误测量相对于第一个在接收器检测到的路径。多普勒频率

取决于终端站，光速c，载波频率fc的速度和发病路径分配给速度v波αp角度页具有相应通道传输信道冲激响应函数图1-2所示。

延迟功率密度谱ρ（τ）为特征的频率选择性移动无线电频道给出了作为通道的输出功能延迟τ平均功率。平均延迟τ，均方根（RMS）的时延扩展τRMS和最大延迟τmax都是延迟功率密度谱特征参数。平均时延特性参数为

有

图1-2时变信道冲激响应和通道传递函数频率选择性衰落是权力页的路径均方根时延扩展的定义为 同样，多普勒频谱的功率密度（FD）的特点可以定义

在移动时变无线信道，并给出了作为一种金融衍生工具功能的多普勒频率通道输出的平均功率。多径信道频率分散性能是最常见的量化发生的多普勒频率和多普勒fDmax蔓延fDspread最大。多普勒扩散是功率密度的多普勒频谱带宽，可价值观需要两年时间| fDmax|，即

1.1.3频道淡出统计

在衰落过程中的统计特征和重要的渠道是信道模型参数规格。一个简单而经常使用的方法是从假设有一个通道中的散射，有助于在大量接收端的信号。该中心极限定理的应用导致了复杂的值的高斯信道冲激响应过程。在对视线（LOS）或线的主要组成部分的情况下，这个过程是零的意思。相应的通道传递函数幅度

是一个随机变量，通过给定一个简短表示由瑞利分布，有

是的平均功率。相均匀分布在区间[0，2π]。

在案件的多通道包含洛杉矶的或主要组件除了随机移动散射，通道脉冲响应可以不再被建模为均值为零。根据信道脉冲响应的假设一个复杂的值高斯过程，其大小通道的传递函数A的水稻分布给出

赖斯因素KRice是由占主导地位的路径权力的威力比分散的路径。I0是零阶贝塞尔函数的第一阶段是一致kind.The在区间[0，2π]分发。

1.1.4符号间（ISI）和通道间干扰（ICI）

延迟的蔓延引起的符号间干扰（ISI）当相邻的数据符号上的重叠与互相不同的传播路径，由于不同的延迟干涉。符号的干扰在单载波调制系统的号码是给予

对于高数据符号持续时间很短运输署<蟿MAX时，ISI的影响，这样一来，速率应用，接收机的复杂性大大增加。对干扰影响，可以抵消，如时间或频域均衡不同的措施。在扩频系统，与几个臂Rake接收机用于减少通过利用多径分集等，个别武器适应不同的传播路径的干扰影响。

如果发送符号的持续时间明显高于大的最大延迟运输署蟿最大，渠道产生ISI的微不足道。这种效果是利用多载波传输的地方，每发送符号的增加与子载波数控数目，因此，ISI的金额减少的持续时间。符号的干扰多载波调制系统的号码是给予

可以消除符号间干扰由一个保护间隔（见1.2节）的使用。

最大多普勒在移动无线应用传播使用单载波调制通常比相邻通道，这样，干扰对由于多普勒传播相邻通道的作用不是一个单载波调制系统的问题距离。对于多载波调制系统，子通道间距FS可以变得非常小，这样可以造成严重的多普勒效应ICI的。只要所有子载波只要是一个共同的多普勒频移金融衍生工具的影响，这可以补偿多普勒频移在接收器和ICI是可以避免的。但是，如果在对多普勒子载波间隔为几个百分点的蔓延情况，卜内门可能会降低系统的性能显着。为了避免性能降级或因与ICI卜内门更复杂的接收机均衡，子载波间隔财政司司长应定为

这样说，由于多普勒效应可以忽略不扩散（见第4章）。这种方法对应于OFDM的1.2节中所述，是目前基于OFDM的无线标准遵循的理念。

不过，如果多载波系统的设计选择了这样的多普勒展宽在子载波间隔或更高，秩序是在频率RAKE接收机域名可以使用[22]。随着频域RAKE接收机每个支部耙解决了不同的多普勒频率。

1.1.5多径信道模型的离散的例子

各类离散多与不同的细胞大小的室内和室外蜂窝系统的信道模型已经被指定。这些通道模型定义的离散传播路径的统计信息。一种广泛使用的离散多径信道模型概述于下。造价207[8]：成本207信道模型指定连续四个室外宏蜂窝传播方案，指数下降延迟功率密度谱。这些频道功率密度的离散谱的实现都是通过使用多达12个频道。与6频道设置的示例列于表1-1。在这种传播环境的几个表中的相应路径延迟和电源配置给出。丘陵地形导致最长相呼应。

经典的多普勒频谱与均匀分布的到达角路径可以用于简化所有的频道。或者，不同的多普勒谱定义在[8]个人频道。207信道的成本模型是基于一个8-10兆赫的2G，如GSM系统中使用的900兆赫频段信道带宽的测量。造价231[9]和造价259[10]：这些费用是行动的延续成本207扩展通道特性到DCS1800的DECT，HIPERLAN和UMTS的渠道，同时考虑到宏观，微观和微微小区的情况为例。空间分辨率与已定义的通道模型在造价259。空间部分是介绍了与当地散射，这是在基站周围设几组圆的定义。三种类型的通道模型定义。宏细胞类型具有高达500〜5000米，载波频率为900兆赫或1.8 GHz的单元尺寸。微细胞类型被定义为细胞体积约300米，1.2 GHz或5 GHz载波频率。细胞类型代表的Pico与细胞体积小于100工业建筑物和办公室中的10 m阶米室内信道模型。载波频率为2.5 GHz或24千兆赫。造价273：成本273行动另外考虑到多天线信道模型，这是不是由先前的费用的行为包括在内。

CODIT [7]：这些通道模型定义的宏，微，微微蜂窝和室外和室内传播的典型案例。各种传播环境的衰落特性是指定的在NakagamiSS）的不同扩频码L是长度，如图1-3所示的系统。没有其他的分集技术被应用。QPSK调制用于符号映射。移动无线信道建模为不相关瑞利衰落信道（见1.1.6）。由于这些曲线显示，办法，AWGN信道的一对L时，对MC-SS系统性能有很大价值。

另一种实现形式的OFDM系统的多样性是由前向纠错信道编码，在这里，每个数据位的信息分散在几个代码位。附加在衰落信道分集增益，编码增益一个可因适当的编码和解码算法的选择。

第五篇：中英文翻译

蓄电池 battery 充电 converter 转换器 charger

开关电器 Switch electric 按钮开关 Button to switch 电源电器 Power electric 插头插座 Plug sockets