第一篇：論文中英文翻譯(譯文)（模版）

編號： 桂林電子科技大學(xué)信息科技學(xué)院

畢業(yè)設(shè)計(論文)外文翻譯

（譯文）

系別：電子工程系

專業(yè)：電子信息工程

學(xué)生姓名：韋 駿

學(xué)號：0852100329

指導(dǎo)教師單位：姓名：

職稱：講 師

2012年 6月 5日

設(shè)計與實現(xiàn)基于 Modbus 協(xié)議的嵌入式 Linux 系統(tǒng)

摘要：隨著嵌入式計算機(jī)技術(shù)的飛速發(fā)展，新一代工業(yè)自動化數(shù)據(jù)采集和監(jiān)測系統(tǒng)，采用核心的高性能嵌入式微處理器的，該系統(tǒng)很好地適應(yīng)應(yīng)用程序。它符合消費等的嚴(yán)格要求的功能，如可靠性，成本，尺寸和功耗等。在工業(yè)自動化應(yīng)用系統(tǒng)，Modbus 通信協(xié)議的工業(yè)標(biāo)準(zhǔn)，廣泛應(yīng)用于大規(guī)模的工業(yè)設(shè)備系統(tǒng)，包括 DCS，可編程控制器，RTU 及智能儀表等。為了達(dá)到嵌入式數(shù)據(jù)監(jiān)測的工業(yè)自動化應(yīng)用軟件的需求，本文設(shè)計了嵌入式數(shù)據(jù)采集監(jiān)測平臺下基于 Modbus 協(xié)議的 Linux 環(huán)境采集系統(tǒng)。串行端口的 Modbus 協(xié)議是實現(xiàn)主/從式，其中包括兩種通信模式：ASCII 和 RTU。因此，各種藥膏協(xié)議的設(shè)備能夠滿足串行的 Modbus通信。在 Modbus 協(xié)議的嵌入式平臺實現(xiàn)穩(wěn)定和可靠。它在嵌入式數(shù)據(jù)監(jiān)測自動化應(yīng)用系統(tǒng)的新收購的前景良好。關(guān)鍵詞：嵌入式系統(tǒng)，嵌入式 Linux，Modbus 協(xié)議，數(shù)據(jù)采集，監(jiān)測和控制。

1、緒論

Modbus 是一種通訊協(xié)議，是一種由莫迪康公司推廣。它廣泛應(yīng)用于工業(yè)自動化，已成為實際的工業(yè)標(biāo)準(zhǔn)。該控制裝置或不同廠家的測量儀器可以鏈接到一個行業(yè)監(jiān)控網(wǎng)絡(luò)使用Modbus 協(xié)議。Modbus 通信協(xié)議可以作為大量的工業(yè)設(shè)備的通訊標(biāo)準(zhǔn)，包括 PLC，DCS 系統(tǒng)，RTU 的，聰明的智能儀表。隨著嵌入式計算機(jī)技術(shù)的飛速發(fā)展，嵌入式數(shù)據(jù)采集監(jiān)測系統(tǒng)，使用了高性能的嵌入式微處理器為核心，是一個重要的發(fā)展方向。在環(huán)境鑒于嵌入式 Linux 的嵌入式工業(yè)自動化應(yīng)用的數(shù)據(jù)，一個 Modbus 主協(xié)議下的采集監(jiān)測系統(tǒng)的設(shè)計和實現(xiàn)了這個文件。因此，通信設(shè)備，各種藥膏協(xié)議能夠滿足串行的 Modbus。

2、Modbus 協(xié)議簡介

Modbus 協(xié)議包括 ASCII 碼，RTU 和 TCP 傳輸模式，支持傳統(tǒng)的 RS422，RSboot 的是先通過串口下載到開發(fā)板，然后使用串口或網(wǎng)絡(luò)的方法。由于內(nèi)核和文件系統(tǒng)的反映是相當(dāng)大的文件，通過串行端口傳輸速度緩慢;以太網(wǎng)模式用于下載內(nèi)核和文件系統(tǒng)。當(dāng)然，網(wǎng)絡(luò)的 Uboot 命令模式的 uboot：已編譯的 Linux 可以操作臂后進(jìn)行 bootm 21000000。內(nèi)核和文件系統(tǒng)中內(nèi)存可以通過閃存寫入啟動處長秩序的 u。該系統(tǒng)能自動運行后，設(shè)置啟動參數(shù)。然后程序操作的開發(fā)板。

4.2、串行配置的 Modbus 協(xié)議在 Linux 環(huán)境下標(biāo)準(zhǔn)的 Modbus 串行協(xié)議使用的 RS232/RS485 傳輸。串行設(shè)備設(shè)備節(jié)點為/dev/ttyS0 來（COM1 端口）dev/ttyS1 COM2 端口）Linux 環(huán)境。和/（在由于 Modbus串行協(xié)議包括兩種傳輸模式：ASCII 和 RTU 模式。起始標(biāo)記和結(jié)束標(biāo)記的兩種模式是不同的。此外，每個信息包數(shù)據(jù)的位置也不同。因此，必須單獨處理。以RTU 模式為例，介紹在 Linux 環(huán)境下的 Modbus 串行協(xié)議配置。頭文件由串行操作需要的是：當(dāng) Modbus 協(xié)議的特點是采用 RTU 傳輸模式下，串行波特率，數(shù)據(jù)位，停止位置，檢查位置和控制應(yīng)根據(jù)設(shè)定的框架特征的信息。建立串口波特率：在設(shè)計中，以使其得到方便。功能參數(shù)，是一個結(jié)構(gòu)的定義如下凡

slave_address 就是從站地址。一個 Modbus 網(wǎng)絡(luò)允許最多 255 個從站。該函數(shù)是服務(wù)模式的選擇特點，并有六種服務(wù)模式在本系統(tǒng)提供的，分別為 1-6。該 start_address 是 16 位字符，這是目前從站供電設(shè)備的起始地址。該pointnum_or_setdata 包括 2 種文字，服務(wù) 1-4 是點頭人數(shù)增加經(jīng)營，服務(wù) 5 和6 是 16 位字符正在建立。該方案首先確定了格式字符值，建立了傳輸模式，用戶需要，這將決定哪些串行配置功能和服務(wù)功能什么樣的選擇。然后設(shè)置串口參數(shù)在 Linux 環(huán)境。相應(yīng)的服務(wù)結(jié)構(gòu)功能是通過判斷用戶的請求服務(wù)類型的選擇。例如，如果格式為 0，采用 RTU 模式。該函數(shù)是 1，這意味著用戶請求讀取線圈。該方案通過使用 construct_rtu_frm 構(gòu)造函數(shù)是rtu_read_status 函數(shù)調(diào)用的 Modbus 的請求幀。該方案保留了串行傳輸緩沖區(qū)mod_tx_buf，這是事先定義它，然后把通過調(diào)用命令的 Modbus 串行傳輸請求幀。如果程序設(shè)定的時間內(nèi)得到答復(fù)框架，該方案將處理答復(fù)幀通過調(diào)用相應(yīng)的模式解析函數(shù)。舉例來說，當(dāng)是 ASCII 傳輸模式，在 ascii_data_anlys 函數(shù)被調(diào)用，如果傳輸模式是 RTU 模式，然后

rtu_data_anlys 函數(shù)被調(diào)用。解析函數(shù)的分析數(shù)據(jù)，接收緩沖區(qū)接收串行。如果答復(fù)框架分析是正確的，該函數(shù)將數(shù)據(jù)加載到目標(biāo)緩沖區(qū)。如果是錯誤的，該函數(shù)將終止這項服務(wù)，并處理錯誤，打印錯誤信息了。

4.3、Modbus 協(xié)議的串行軟件設(shè)計

這里主要介紹了方案的設(shè)計與實現(xiàn)串行 Modbus 協(xié)議，其中包括兩種傳輸模式

RTU 和 ASCII。在 Modbus 主機(jī)服務(wù)包括人機(jī)交互模塊，功能選擇模塊，功能處理模塊和返回處理模塊。每個模塊的功能是實現(xiàn)了在嵌入式 Linux 環(huán)境。人機(jī)交互模塊是為用戶和平臺的通信模塊。它主要實現(xiàn)了網(wǎng)頁打印功能，用戶信息的輸入和指導(dǎo)等。該函數(shù)的選擇模塊是平臺選擇的 Modbus 主函數(shù)的選擇參數(shù)根據(jù)用戶輸入的信息。這些參數(shù)包括傳播方式的，服務(wù)類型，從站地址等。該函數(shù)處理模塊是這個平臺的核心。它包括串口初始化的功能，結(jié)構(gòu)的Modbus 幀，模態(tài)分析的 Modbus 幀，各類業(yè)務(wù)處理和業(yè)務(wù)處理等 6 種主要的設(shè)計，其中包括：為串行的 Modbus 設(shè)備在這個平臺閱讀線圈狀態(tài)，讀輸入狀態(tài)，讀保持寄存器，讀輸入寄存器，寫，寫單線圈單登記。這 6 種的模式涵蓋了 Modbus的基本功能需求。而這是非常方便的擴(kuò)大，如果必要的其他職能。返回處理模塊流程操作平臺的結(jié)果。如果用戶請求的服務(wù)流程成功，服務(wù)結(jié)果將通過標(biāo)準(zhǔn)打印輸出設(shè)備，否則錯誤信息打印。

4.4、服務(wù)的結(jié)構(gòu)和功能分析框架

以讀持有注冊服務(wù)為例，介紹了施工過程中要求的 Modbus 幀。該函數(shù)讀取保存寄存器數(shù)是 03 和建設(shè)要求的 Modbus 幀是實現(xiàn)通過 rtu_read_hldreg 和ascii_read_hldreg 功能。前者實現(xiàn)了 RTU 的框架結(jié)構(gòu)，而后者的 ASCII 框架結(jié)構(gòu)。該 rtu_read_hldreg 結(jié)構(gòu)如下所示：輸入?yún)?shù) board_adr 就是從站地址，用戶需要訪問的。是緩沖區(qū)的 com_buf了 Modbus 幀傳輸領(lǐng)域。該 start_address 是訪問的起始地址和長度 lenth 是訪問的。所有這些變量，則是通過結(jié)構(gòu)模塊參數(shù)的人機(jī)互動。高（）和低（）是兩個定義的函數(shù)。該高（）是為了獲得高的 8 位，低（）是獲得低 8 位。該 construct_rtu_frm 功能是 RTU 的框架結(jié)構(gòu)。所有的服務(wù)都是通過調(diào)用此函數(shù)實現(xiàn)，形成 RTU 的請求幀。其結(jié)構(gòu)如下所示：經(jīng)過這些步驟，一幀請求已完成制作。最后，為了寫（fd，mod_tx_buf，tx_len）是通過調(diào)用串行端口發(fā)送和傳輸緩沖區(qū)的請求的 Modbus 幀傳輸。tx_len 是服凡務(wù)構(gòu)造函數(shù)返回值。請求幀傳輸后，該方案將等待從站回應(yīng)。為了避免無休止的循環(huán)機(jī)制，通過檢測從站沒有回應(yīng)，建立一個加班。如果從站并沒有在預(yù)定時間響應(yīng)，程序產(chǎn)生一個錯誤消息并停止該服務(wù)。如果服務(wù)程序在預(yù)定的時間收到答復(fù)框架，分析了通過調(diào)用

解析函數(shù)的答復(fù)時限。

5、結(jié)論

Modbus 通信協(xié)議的廣泛使用，已成為事實上的工業(yè)標(biāo)準(zhǔn)，其實。它是用大量的工業(yè)設(shè)備作為它們之間的通訊標(biāo)準(zhǔn)，包括 DCS，可編程控制器，RTU 通訊，智能儀表及監(jiān)控系統(tǒng)等新一代工業(yè)自動化數(shù)據(jù)采集采用高性能嵌入式微處理器為核心。因此，它適應(yīng)應(yīng)用程序很好地滿足功能性，可靠性，成本，體積，功耗等嚴(yán)格要求，為了達(dá)到嵌入的數(shù)據(jù)監(jiān)測的工業(yè)自動化應(yīng)用，系統(tǒng)采集要求 Modbus協(xié)議的主站上的嵌入式數(shù)據(jù)采集監(jiān)測 Linux 環(huán)境下的平臺，是本文設(shè)計的基礎(chǔ)。每個從站之間的通信實現(xiàn)。根據(jù)掌握的 Modbus 的嵌入式 Linux 環(huán)境服務(wù)程序運行穩(wěn)定，可靠的測試后，Modbus 協(xié)議。它提供了良好服務(wù)的 Modbus 主站，并符合標(biāo)準(zhǔn)的 Modbus 協(xié)議。其在工業(yè)自動化數(shù)據(jù)采集監(jiān)測系統(tǒng)的新一代應(yīng)用前景非常好。

6、鳴謝

這項工作支持的項目一部分由上?？萍脊リP(guān)項目（編號 061111004），上海曙光跟蹤計劃（第 06GG13）和上海領(lǐng)先學(xué)科項目。

7、參考資料

[1] 第十一波，方艷 6 月應(yīng)用嵌入在串口設(shè)備聯(lián)網(wǎng)技術(shù)[J]。電力自動化設(shè)備，2007，27（8）99-101。

[2] 張浩，黃云彥，彭道崗。EGI 立足于預(yù)警系統(tǒng)研究[J] Modbus 協(xié)議。機(jī)電一體化，2007，13（2）:15

8。

[3] 李娟，張波，丘東元。多機(jī)通信與 Modbus RTU 的總部設(shè)在電能質(zhì)量監(jiān)測系統(tǒng)[J]。電力自動化

設(shè)備，2007，27，（1）:9310。

[5] 閔華松，劉光臨。嵌入式狀態(tài)監(jiān)測與故障診斷系統(tǒng)的高速旋轉(zhuǎn)機(jī)械的研究[J]。信息與控制，2006,35

（3）：309-313。

[6] 鮑可進(jìn)，鄔建勇。對權(quán)力的執(zhí)行情況與嵌入式 Web 服務(wù)器系統(tǒng)[J]遠(yuǎn)程監(jiān)控。計算機(jī)工程與設(shè)計，2007,28（13）：3178-3180。

第二篇：運籌學(xué)論文中英文翻譯

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

mining problem 多期露天采礦的最大流公式

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.我們認(rèn)為在若干期間，找到一個最佳的露天采礦的開采順序，只會受到空間和時間的優(yōu)先約束。這個問題很有趣，因為這些約束通用于任何露天礦調(diào)度問題，特別是因為它是作為露天礦調(diào)度的拉格朗日松弛算法而出現(xiàn)的。我們可以將這種多期露天開采的問題作為一個時間擴(kuò)張礦圖的最大流問題來解決。此外，本圖中的最小割集將定義的礦坑的最佳順序。這個結(jié)果是J.C.Picard著名理論的延伸，J.C.Picard從1976年就研究露天礦設(shè)計問題，即，單周期的情況下，對多個時間段的研究。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

露天開采是一個表面采礦作業(yè)，從地面挖掘出礦石或廢物，因此形成一個越來越深的坑。在開始采礦前，通常把礦床劃分成塊，通過鉆孔的地質(zhì)信息估計每塊礦床的價值。每塊礦床的開采和加工成本也能估計。利潤可以分配給每個礦山 模型，如圖所示。

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.在露天礦山規(guī)劃中，一個基本問題是決定開采哪塊礦。這被稱為尋找露天礦山設(shè)計的問題，或礦井的最終輪廓問題。唯一的限制是空間優(yōu)先的關(guān)系，指出為了提取任何給定的礦塊，所有礦塊必須在上面和在要求的壁面收斂角范圍內(nèi)。勒奇斯和格羅斯曼（1965）表明，設(shè)計問題可以表述為在礦圖中尋找最大閉合的問題，這幅礦圖能表現(xiàn)礦塊和優(yōu)先級限制，如圖1所示（45°的安全坡度）。多年來，他們用來在礦圖中尋找最大閉合的公式，在采礦業(yè)的露天礦設(shè)計中也被普遍使用。

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.露天礦設(shè)計問題的實際意義是使其成為最大閉合問題中的一個重要實例（皮卡德和凱拉納，1982）。皮卡德（1976）表明，在礦圖中尋找最大閉合的問題

可以作為礦圖中網(wǎng)狀圖的最大流問題來解決，礦圖中，最小割集確定最佳礦井輪廓。后來，陳（2000）和霍赫鮑姆（2001）研究出高效的露天開采的最大流算法。

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.在現(xiàn)實中，一個礦塊的利潤取決于開采時，例如由于打折。這個事實導(dǎo)致了露天礦山規(guī)劃的另一個關(guān)鍵問題，即調(diào)度。這是決定何時開采、如何開采并使利潤最大化（通常是凈現(xiàn)值）的過程，同時遵守墻坡和優(yōu)先約束，并受到各種開采能力的限制。Gershon(1983), Dagdelen 和 Johnson(1986), Caccetta和Hill(2003), Ramazan(2007), Rafiee和Asghari(2008), Bley et al.Cullenbineetal(2011)等人已經(jīng)從數(shù)學(xué)優(yōu)化的角度給出了露天礦山調(diào)度的貢獻(xiàn)。

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.我們只考慮有空間和時間優(yōu)先約束的多周期的露天開采問題。后者簡單闡明，一旦礦塊被開采，應(yīng)當(dāng)繼續(xù)開采?？臻g和時間的優(yōu)先約束通用于露天礦調(diào)度和多周期問題，它作為拉格朗日松弛的露天作業(yè)調(diào)度問題而出現(xiàn)，此時能力限制符合拉格朗日對偶。

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，這個多期露天開采問題是可以當(dāng)作時間擴(kuò)張礦圖中的最大流問題，時間擴(kuò)張礦圖中含有每個時期的礦圖副本。擴(kuò)張圖還包含模仿礦圖連續(xù)副本中相應(yīng)節(jié)點間暫時優(yōu)先關(guān)系的有向弧，這些弧與每幅礦圖中模仿空間優(yōu)先級關(guān)系的弧是相似的。這個最大流量公式是皮卡爾（1976）對于多期研究結(jié)果的擴(kuò)展。圖2顯示了圖1中礦圖的時間擴(kuò)展，此時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部分給出了數(shù)學(xué)模型。第3部分呈現(xiàn)了時間擴(kuò)張礦圖中的最大流問題，并且表明，本圖的最小割集定義了多期問題的最優(yōu)解。

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

一個帶有利潤價值及礦圖的礦塊模型

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.圖2 三個時間段露天開采問題時間擴(kuò)張礦圖。

第4部分給出了一個小例子。最后一部分節(jié)給出了結(jié)束語。The mathematical model 數(shù)學(xué)模型

The following notation will be used.將使用到下面的符號。

T

number of time periods.時間段的數(shù)量

V

set of all blocks that can be mined.可以開采的礦塊集合

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.礦塊(i, j)的集合，礦塊j與礦塊i 相鄰的礦塊，要想開采礦塊i，必須先移除礦塊j contribution to the objective value if block i is mined in time period t or earlier，如果在時間段t 或早些時候開采礦塊i，對于客觀價值的貢獻(xiàn)

Defining the decision variables for all對于所有的，定義決策變量

if block i is mined in time period t or earlier如果在時間段t 或早些時候開采礦塊i

0

Otherwise

其他情況 the multi-period open-pit mining problem is formulated as 多期露天礦山開采問題可表述為

subject to 滿足

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.第一個和第二個約束集合是各個空間暫時的優(yōu)先限制。正如所表明的一樣，通過求解時間擴(kuò)張礦圖中的最大流問題，找到這一問題的最優(yōu)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

為了陳述時間擴(kuò)張的最大流問題，我們引入礦塊結(jié)點的集合和絡(luò)的源結(jié)點和匯聚結(jié)點，包括從源結(jié)點到結(jié)點到匯聚結(jié)點的弧。讓，最大流問題如下。，進(jìn)一步讓和成為各個網(wǎng)的弧，從結(jié)點

并且

滿足

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).這里，f是總流量，分量

是在時間段t內(nèi)從結(jié)點i到結(jié)點j的流量，每個

對應(yīng)一個連續(xù)時間段內(nèi)對應(yīng)礦塊結(jié)點之間的正向弧。此外，源結(jié)點到礦塊結(jié)點i的流量，是在時間段 t內(nèi)從

在時間段 t內(nèi)從礦塊結(jié)點i到匯聚結(jié)點的流量。圖3給出了一個最大流量網(wǎng)絡(luò)的例子，圖中有9個礦塊和3個時間段（但是只表示了部分?。?。

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

andthrough the mine graph copy for time period t.讓成為時間擴(kuò)張最大流網(wǎng)絡(luò)中的最小割集。那么，圖副本的割集。

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

是通過時間段t的礦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

理論一

問

題

(1)的最優(yōu)解為

并且

證明

我們學(xué)習(xí)了上述最大流問題的對偶線性規(guī)劃。讓成為和網(wǎng)絡(luò)圖中的礦塊結(jié)點相一致的對偶變量，讓和匯聚結(jié)點相關(guān)聯(lián)的對偶變量。通過進(jìn)一步引入偶變量是上界約束，對偶問題變?yōu)?/p>

成為分別與源結(jié)點，由于對滿足

(例如., Bazaraa 和 Jarvis 1977)給出對偶問題的最優(yōu)解

Fig.3 Example of the maximum flow network(with sample arcs)圖3 最大流網(wǎng)絡(luò)圖實例（樣本?。〢nd 并且

Then, for

那么，對于

and for

對于

It then holds that 然后，得到

subject to the constraints(3)–(8)and to 滿足限制條件(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.對于問題（2）來說，最優(yōu)解仍然是最佳的，因為和r局限于各自的最佳值并且執(zhí)行等式（9）和（10）以保證任何解都不會影響其最優(yōu)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

很容易驗證，限制條件（3）–（5）可以從問題（11）中去除，因為它們一直被滿足。通過進(jìn)一步從問題（11）中消除變量它減小為 ,和，subject to 滿足

Now, letproblem can be stated as 現(xiàn)在，對于所有的問題可以陳述為

讓

然后，上述

for all

Then the above

subject to滿足

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.因為這個最優(yōu)解是二元的，因此，它也是問題（1）的最優(yōu)解。其最佳值的表達(dá)式直接符合上面的目標(biāo)函數(shù)。

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由于與變量得到while for t =2,...,Tit is the blocks corresponding to the nodes in

相應(yīng)的向前弧是非限量的，它符合當(dāng)

。因此，割集序列

時，所以，定

中的結(jié)點，當(dāng)t 義越來越大的礦坑。在第一時間段，精確開采的礦塊對應(yīng)集合=2,...,時，Tit就是與集合

中的結(jié)點相對應(yīng)的礦塊。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

簡介中提到，我們所考慮的問題很有趣，因為當(dāng)露天礦山的調(diào)度問題是拉格朗日輕松時，它才出現(xiàn)。為了說明這一點，我們考慮以下的調(diào)度模型，布萊等人認(rèn)為這是此模型的特殊情況（2010）。

subject to 滿足

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

決策變量的定義同上。（注意，當(dāng)?shù)V塊 i正好在時間段t開采時，差值為1）。此外，的噸位，是在時間段t開采礦塊 i時獲得的利潤，是礦塊 i是時間段t的一個上限噸位。讓 作為與每個時間段內(nèi)最大噸位約束相關(guān)聯(lián)的乘數(shù)，拉格朗日松弛這些限制，我們得到問題（1）的一個實例，目標(biāo)函數(shù)的系數(shù)成為拉格朗日下降利潤。

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.讀者可能會注意到，如果問題（12）的線性規(guī)劃松弛是通過一個列生成方案解決的話，問題（1）也將作為一個列生成問題出現(xiàn)（或者，定價問題）。

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

圖4 定義挖掘順序的最小割集

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.為了說明該定理的結(jié)果，我們考慮到圖1中的模型，通過讓所有的t滿足，讓所有的 i滿足

構(gòu)造問題（12）的一個實例。而且，利潤值被每個時間段的系數(shù)0.90所折扣。為了創(chuàng)建問題（1）的一個實例，我們 將能力約束與乘數(shù)值

進(jìn)行拉格朗日松弛。[這些數(shù)值來自于問題（12）的線性規(guī)劃松弛的對偶]。時間擴(kuò)張最大流問題的最小割集如圖4所示。結(jié)果表明，礦塊2和礦3是在第一時間段開采的，礦塊4和礦塊6在第二時間段開采的，礦塊1和礦塊5是在最后一個時間段開采的。最優(yōu)利潤是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

結(jié)論

我們已經(jīng)給出了多期露天開采的最大流量公式。它擴(kuò)充了皮卡爾(1976)經(jīng)典的最大流公式，該公式借助時間擴(kuò)張網(wǎng)絡(luò)，針對單一時間段進(jìn)行研究。皮卡爾的推導(dǎo)基于將露天礦山設(shè)計問題轉(zhuǎn)化為一個二次二進(jìn)制程序的再形成，基于線性規(guī)劃對偶，我們正確證明了時間擴(kuò)張最大流。

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.本文中所考慮的問題是自然產(chǎn)生的，如果除空間和時間約束條件外，所有的 露天礦山的調(diào)度問題都是拉格朗日對偶，或被排出列生成。對于拉格朗日因子的任何值，在時間擴(kuò)張網(wǎng)絡(luò)圖中的最大流的解對應(yīng)一個對于空間和時間優(yōu)先限制都可行的采掘計劃。拉格朗日因子可以被認(rèn)作應(yīng)調(diào)整的參數(shù)，這樣以最佳的方式實現(xiàn)能力限制。因為普遍存在對偶間隙，這種策略不能最好地解決調(diào)度問題。

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.很明顯，進(jìn)一步的研究機(jī)會是基于時間擴(kuò)張最大流問題的拉格朗日對偶和列生成方法的研究，作為啟發(fā)式地或最佳地解決露天礦山調(diào)度問題的工具。

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47、柔性制造系統(tǒng)

48、潤滑和摩擦學(xué)在海水水力活塞泵中的應(yīng)用

49、生產(chǎn)膠粉—廢舊輪胎回收利用的方向

50、事例研究—反求工程零部件的遠(yuǎn)程制造

51、數(shù)控技術(shù)和裝備發(fā)展趨勢及對策

52、數(shù)控技術(shù)和裝備發(fā)展趨勢及對策153、數(shù)字控制

54、鐵金屬及其合金

55、先進(jìn)制造技術(shù)的新發(fā)展

56、現(xiàn)代集成制造技術(shù)

57、現(xiàn)代集成制造系統(tǒng)的技術(shù)構(gòu)成及發(fā)展策略研究

58、現(xiàn)代制造業(yè)中計算機(jī)的應(yīng)用

59、虛擬制造的機(jī)械加工過程仿真

60、虛擬制造技術(shù)及其應(yīng)用

61、選域激光熔解法在鈦?？焖僭图庸ぶ械淖饔?/p>

62、研磨機(jī)的最佳優(yōu)化設(shè)計

63引線鍵合的現(xiàn)狀與發(fā)展趨勢

64、影響切割工藝的材料屬性的總體

65、在干和濕的高速加工環(huán)境下表面涂上碳化物和不涂碳化物對產(chǎn)品生命周期的影響

66、在干燥和潮濕的條件下研究高速切削的費用以及便于機(jī)械制造過程的優(yōu)化

67、在高速潮濕機(jī)械加工條件下后刀面表層磨損機(jī)理

68、在高速干加工條件下含有TIALN涂層的插入物磨損機(jī)理的實驗性觀察

69、制造業(yè)為產(chǎn)品設(shè)計花費模型

第四篇：中英文翻譯

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, ?p, 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 ?n,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 ?n,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.中文翻譯 1基本原理

這章描述今日的基本面的無線通信。第一一個的詳細(xì)說明無線電頻道，它的模型被介紹，跟隨附近的的介紹的原則的參考正交頻分復(fù)用多載波傳輸。此外，一個一般概觀的擴(kuò)頻技術(shù)，尤其ds-cdma，被給，潛力的例子申請參考正交頻分復(fù)用，DS對1。分配的通道傳輸功能是

有關(guān)的延誤測量相對于第一個在接收器檢測到的路徑。多普勒頻率

取決于終端站，光速c，載波頻率fc的速度和發(fā)病路徑分配給速度v波αp角度頁具有相應(yīng)通道傳輸信道沖激響應(yīng)函數(shù)圖1-2所示。

延遲功率密度譜ρ（τ）為特征的頻率選擇性移動無線電頻道給出了作為通道的輸出功能延遲τ平均功率。平均延遲τ，均方根（RMS）的時延擴(kuò)展τRMS和最大延遲τmax都是延遲功率密度譜特征參數(shù)。平均時延特性參數(shù)為

有

圖1-2時變信道沖激響應(yīng)和通道傳遞函數(shù)頻率選擇性衰落是權(quán)力頁的路徑均方根時延擴(kuò)展的定義為 同樣，多普勒頻譜的功率密度（FD）的特點可以定義

在移動時變無線信道，并給出了作為一種金融衍生工具功能的多普勒頻率通道輸出的平均功率。多徑信道頻率分散性能是最常見的量化發(fā)生的多普勒頻率和多普勒fDmax蔓延fDspread最大。多普勒擴(kuò)散是功率密度的多普勒頻譜帶寬，可價值觀需要兩年時間| fDmax|，即

1.1.3頻道淡出統(tǒng)計

在衰落過程中的統(tǒng)計特征和重要的渠道是信道模型參數(shù)規(guī)格。一個簡單而經(jīng)常使用的方法是從假設(shè)有一個通道中的散射，有助于在大量接收端的信號。該中心極限定理的應(yīng)用導(dǎo)致了復(fù)雜的值的高斯信道沖激響應(yīng)過程。在對視線（LOS）或線的主要組成部分的情況下，這個過程是零的意思。相應(yīng)的通道傳遞函數(shù)幅度

是一個隨機(jī)變量，通過給定一個簡短表示由瑞利分布，有

是的平均功率。相均勻分布在區(qū)間[0，2π]。

在案件的多通道包含洛杉磯的或主要組件除了隨機(jī)移動散射，通道脈沖響應(yīng)可以不再被建模為均值為零。根據(jù)信道脈沖響應(yīng)的假設(shè)一個復(fù)雜的值高斯過程，其大小通道的傳遞函數(shù)A的水稻分布給出

賴斯因素KRice是由占主導(dǎo)地位的路徑權(quán)力的威力比分散的路徑。I0是零階貝塞爾函數(shù)的第一階段是一致kind.The在區(qū)間[0，2π]分發(fā)。

1.1.4符號間（ISI）和通道間干擾（ICI）

延遲的蔓延引起的符號間干擾（ISI）當(dāng)相鄰的數(shù)據(jù)符號上的重疊與互相不同的傳播路徑，由于不同的延遲干涉。符號的干擾在單載波調(diào)制系統(tǒng)的號碼是給予

對于高數(shù)據(jù)符號持續(xù)時間很短運輸署<蟿MAX時，ISI的影響，這樣一來，速率應(yīng)用，接收機(jī)的復(fù)雜性大大增加。對干擾影響，可以抵消，如時間或頻域均衡不同的措施。在擴(kuò)頻系統(tǒng)，與幾個臂Rake接收機(jī)用于減少通過利用多徑分集等，個別武器適應(yīng)不同的傳播路徑的干擾影響。

如果發(fā)送符號的持續(xù)時間明顯高于大的最大延遲運輸署蟿最大，渠道產(chǎn)生ISI的微不足道。這種效果是利用多載波傳輸?shù)牡胤?，每發(fā)送符號的增加與子載波數(shù)控數(shù)目，因此，ISI的金額減少的持續(xù)時間。符號的干擾多載波調(diào)制系統(tǒng)的號碼是給予

可以消除符號間干擾由一個保護(hù)間隔（見1.2節(jié)）的使用。

最大多普勒在移動無線應(yīng)用傳播使用單載波調(diào)制通常比相鄰?fù)ǖ?，這樣，干擾對由于多普勒傳播相鄰?fù)ǖ赖淖饔貌皇且粋€單載波調(diào)制系統(tǒng)的問題距離。對于多載波調(diào)制系統(tǒng)，子通道間距FS可以變得非常小，這樣可以造成嚴(yán)重的多普勒效應(yīng)ICI的。只要所有子載波只要是一個共同的多普勒頻移金融衍生工具的影響，這可以補(bǔ)償多普勒頻移在接收器和ICI是可以避免的。但是，如果在對多普勒子載波間隔為幾個百分點的蔓延情況，卜內(nèi)門可能會降低系統(tǒng)的性能顯著。為了避免性能降級或因與ICI卜內(nèi)門更復(fù)雜的接收機(jī)均衡，子載波間隔財政司司長應(yīng)定為

這樣說，由于多普勒效應(yīng)可以忽略不擴(kuò)散（見第4章）。這種方法對應(yīng)于OFDM的1.2節(jié)中所述，是目前基于OFDM的無線標(biāo)準(zhǔn)遵循的理念。

不過，如果多載波系統(tǒng)的設(shè)計選擇了這樣的多普勒展寬在子載波間隔或更高，秩序是在頻率RAKE接收機(jī)域名可以使用[22]。隨著頻域RAKE接收機(jī)每個支部耙解決了不同的多普勒頻率。

1.1.5多徑信道模型的離散的例子

各類離散多與不同的細(xì)胞大小的室內(nèi)和室外蜂窩系統(tǒng)的信道模型已經(jīng)被指定。這些通道模型定義的離散傳播路徑的統(tǒng)計信息。一種廣泛使用的離散多徑信道模型概述于下。造價207[8]：成本207信道模型指定連續(xù)四個室外宏蜂窩傳播方案，指數(shù)下降延遲功率密度譜。這些頻道功率密度的離散譜的實現(xiàn)都是通過使用多達(dá)12個頻道。與6頻道設(shè)置的示例列于表1-1。在這種傳播環(huán)境的幾個表中的相應(yīng)路徑延遲和電源配置給出。丘陵地形導(dǎo)致最長相呼應(yīng)。

經(jīng)典的多普勒頻譜與均勻分布的到達(dá)角路徑可以用于簡化所有的頻道?；蛘?，不同的多普勒譜定義在[8]個人頻道。207信道的成本模型是基于一個8-10兆赫的2G，如GSM系統(tǒng)中使用的900兆赫頻段信道帶寬的測量。造價231[9]和造價259[10]：這些費用是行動的延續(xù)成本207擴(kuò)展通道特性到DCS1800的DECT，HIPERLAN和UMTS的渠道，同時考慮到宏觀，微觀和微微小區(qū)的情況為例?？臻g分辨率與已定義的通道模型在造價259。空間部分是介紹了與當(dāng)?shù)厣⑸?，這是在基站周圍設(shè)幾組圓的定義。三種類型的通道模型定義。宏細(xì)胞類型具有高達(dá)500?5000米，載波頻率為900兆赫或1.8 GHz的單元尺寸。微細(xì)胞類型被定義為細(xì)胞體積約300米，1.2 GHz或5 GHz載波頻率。細(xì)胞類型代表的Pico與細(xì)胞體積小于100工業(yè)建筑物和辦公室中的10 m階米室內(nèi)信道模型。載波頻率為2.5 GHz或24千兆赫。造價273：成本273行動另外考慮到多天線信道模型，這是不是由先前的費用的行為包括在內(nèi)。

CODIT [7]：這些通道模型定義的宏，微，微微蜂窩和室外和室內(nèi)傳播的典型案例。各種傳播環(huán)境的衰落特性是指定的在NakagamiSS）的不同擴(kuò)頻碼L是長度，如圖1-3所示的系統(tǒng)。沒有其他的分集技術(shù)被應(yīng)用。QPSK調(diào)制用于符號映射。移動無線信道建模為不相關(guān)瑞利衰落信道（見1.1.6）。由于這些曲線顯示，辦法，AWGN信道的一對L時，對MC-SS系統(tǒng)性能有很大價值。

另一種實現(xiàn)形式的OFDM系統(tǒng)的多樣性是由前向糾錯信道編碼，在這里，每個數(shù)據(jù)位的信息分散在幾個代碼位。附加在衰落信道分集增益，編碼增益一個可因適當(dāng)?shù)木幋a和解碼算法的選擇。

第五篇：中英文翻譯

蓄電池 battery 充電 converter 轉(zhuǎn)換器 charger

開關(guān)電器 Switch electric 按鈕開關(guān) Button to switch 電源電器 Power electric 插頭插座 Plug sockets