【正文】 n, the split nut can be closed around the lead the split nut closed, the carriage is moved along the lead screw by direct drive without possibility of 14 頁 第 3 頁┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ 裝 ┊ ┊ ┊ ┊ ┊ 訂 ┊ ┊ ┊ ┊ ┊ 線 ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊畢業(yè)設(shè)計（論文）報告紙Modern lathes have a quickchange gear input end of this gear box is driven from the lathe spindle by means of suitable output end of the gear box is connected to the feed rod and lead , through this gear train, leading from the spindle to the quickchange gear box, thence to the lead screw and feed rod, and then to the carriage, the cutting tool can be made to move a specific distance, either longitudinally or transversely, for each revolution of the typical lathe provides, through the feed rod, fortyeight feeds ranging from inch to inch per revolution of the spindle, and, through the lead screw, leads for cutting fortyeight different threads from to 92 per some older and some cheaper lathes, one or two gears in the gear train between the spindle and the change gear box must be changed in order to obtain a full range of threads and TOOLShape of cutting tools, particularly the angles, and tool material are very important purpose of this unit is to introduce the cutting tool geometry and tool Tool GeometryAngles determine greatly not only tool life but finish quality as principles upon which cutting tool angles are based do not depend on the particular , grinding wheel are being , however, the lathe(turning)tool, depicted in , might be easiest to visualize, its geometry is features have been identified by many technical literature is full of confusing in the attempt to clear up existing disorganized conceptions and nomenclature, the American Society of Mechanical Engineers published ASA Standard follows is based on singlepoint tool is a cutting tool having one face and one continuous cutting angles identified in are as follows:(1)Backrake angle,(2)Siderake angle,(3)Endrelief angle(4)Endrelief angle(5)Siderelief angle(6)Endcuttingedge angle,(7)Sidecuttingedge angle,(8)Nose angle,(9)Nose angle 1, on front view, is the backrake is the angle between the tool face and a line parallel to the base of the shank in a longitudinal plane perpendicular to the tool this angle is downward from front to rear of the cutting edge, the rake id positive。相比之下，操作數(shù)據(jù)庫包含的不僅僅是原始數(shù)據(jù)，比如交易數(shù)據(jù)，這些數(shù)據(jù)在進行分析之前需要統(tǒng)一。另外，操作數(shù)據(jù)庫支持幾個交易的并行處理。如此的一個系統(tǒng)需要并發(fā)控制和恢復(fù)機制。這些特征使得用戶在做決策上更簡單。另一方面，數(shù)據(jù)倉庫系統(tǒng)在數(shù)據(jù)分析和決策方面為用戶或“知識工人”提供服務(wù)。然而，數(shù)據(jù)倉庫為集成的異種數(shù)據(jù)庫系統(tǒng)帶來了高性能，因為數(shù)據(jù)被拷貝、預(yù)處理、集成、注釋、匯總，并重新組織到一個語義一致的數(shù)據(jù)存儲中。然后，將這些查詢映射和發(fā)送到局部查詢處理器。(2)根據(jù)季度、年、地區(qū)的營銷情況比較，重新配置產(chǎn)品和管理投資，調(diào)整生產(chǎn)策略；(3)分析運作和查找利潤源；(4)管理顧客關(guān)系、進行環(huán)境調(diào)整、管理合股人的資產(chǎn)開銷?！昂谩保艾F(xiàn)在你可以問什么是數(shù)據(jù)倉庫。(2)集成的：數(shù)據(jù)倉庫通常由多個數(shù)據(jù)源組成，如關(guān)系數(shù)據(jù)庫、一般文件和聯(lián)機事務(wù)處理記錄。數(shù)據(jù)倉庫允許不同應(yīng)用系統(tǒng)的集成，為統(tǒng)一的歷史數(shù)據(jù)分析提供堅實的平臺，對信息處理提供支持。s operational warehouse systems allow for the integration of a variety of application support information processing by providing a solid platform of consolidated, historical data for to , a leading architect in the construction of data warehouse systems, “a data warehouse is a subjectoriented, integrated, timevariant, and nonvolatile collection of data in support of management39。許多組織發(fā)現(xiàn)在如今的具有競爭與快速發(fā)展的世界中數(shù)據(jù)倉庫是非常有用的工具。四個關(guān)鍵詞，面向主題的、集成的、時變的、非易失的，將數(shù)據(jù)倉庫與其它數(shù)據(jù)存儲系統(tǒng)相區(qū)別。數(shù)據(jù)倉庫中所包含的關(guān)鍵字，都顯性或隱性的反映時間元素。利用數(shù)據(jù)倉庫常常需要一些決策支持技術(shù)。集成這些數(shù)據(jù)，并提供簡便、有效的訪問是非常希望的，并且也是一種挑戰(zhàn)。這種方法是低效的，并且對于頻繁的查詢，特別是需要聚集操作的查詢，開銷很大。這樣，建立數(shù)據(jù)倉庫在工業(yè)界就非常流行。OLTP 和OLAP 的主要區(qū)別概述如下。6（4）視圖：聯(lián)機事務(wù)處理系統(tǒng)聚焦于當前企業(yè)或部門數(shù)據(jù)，而不涉及到歷史數(shù)據(jù)或在不同組織中的數(shù)據(jù)。，為什么需要一個分離的數(shù)據(jù)庫？“既然操作數(shù)據(jù)庫存儲了大量的數(shù)據(jù)”，你也看到了，“為什么不直接執(zhí)行在線分析系統(tǒng)數(shù)據(jù)庫替代花費大量時間和資源去構(gòu)建一個分離的數(shù)據(jù)庫？ 這種分離的一個主要的原因是可以提高兩個系統(tǒng)的性能。并行控制和恢復(fù)機制，如果應(yīng)用于聯(lián)機處理系統(tǒng)，可能會危害控制交易的執(zhí)行，那樣的話，會大大地了降低在線分析系統(tǒng)的吞吐量。when upward共 14 頁 第 4 頁┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ 裝 ┊ ┊ ┊ ┊ ┊ 訂 ┊ ┊ ┊ ┊ ┊ 線 ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊畢業(yè)設(shè)計（論文）報告紙from front to back, the rake is angle is most significant in the machining process, because it directly affects the cutting force, finish, and tool siderake angle, numbered 2, measures the slope of the face in a cross plane perpendicular to the tool , also, is an important angle, because it directs chip flow to the side of the tool post and permits the tool to feed more easily into the endrelief angle is measured between a line perpendicular to the base and the end flank immediately below the end cutting edge。決策支持系統(tǒng)需要把從異構(gòu)數(shù)據(jù)中得來的數(shù)據(jù)進行統(tǒng)一，才能得以高效的查詢，純凈的和集成的數(shù)據(jù)。在線分析系統(tǒng)進程查詢在操作數(shù)據(jù)中可能需要降解大量的操作工作。（5）存儲模式：聯(lián)機處理系統(tǒng)組成短小，自動交易。在線分析系統(tǒng)管理大量歷史數(shù)據(jù)，提供總結(jié)和聚集的設(shè)備，存儲和管理不同水平的粒度。它們涵蓋了一個組織的大部分日常操作，如購買、庫存、制造、銀行、工資、注冊、記帳等。與聯(lián)機事務(wù)處理數(shù)據(jù)庫不同，數(shù)據(jù)倉庫不包含最近的信息。當一個查詢提交客戶站點，首先使用元數(shù)據(jù)字典對查詢進行轉(zhuǎn)換，將它轉(zhuǎn)換成相應(yīng)異種站點上的查詢?！敖M織是如何從數(shù)據(jù)倉庫中使用數(shù)據(jù)的？”許多組織使用這些信息支持決策活動，包括：(1)增加顧客關(guān)注，包括分析顧客購買模式（如，喜愛買什么、購買時間、預(yù)算周期、消費習(xí)慣）。數(shù)據(jù)倉庫經(jīng)常被認作一種結(jié)構(gòu)，由集成的數(shù)據(jù)組合而成，支持結(jié)構(gòu)化和啟發(fā)式查詢、分析報告和決策制定。因此，數(shù)據(jù)倉庫排除了在進程中提供的沒有價值的決策。不嚴謹?shù)恼f，數(shù)據(jù)倉庫是一個數(shù)據(jù)庫，它與組織機構(gòu)的操作數(shù)據(jù)庫分別維護。s petitive, fast evolving the last several years, many firms have spent millions of dollars in building enterprisewide data people feel that with petition mounting in every industry, data warehousing is the latest musthave marketing weapon —— a way to keep customers by learning more about their needs.“So“, you may ask, full of intrigue, “what exactly is a data warehouse?”Data warehouses have been defined in many ways, making it difficult to formulate a rigorous speaking, a data warehouse refers to a database that is maintained separately from an organization39。在最近的幾年里，許多公司花了幾百萬美元用于構(gòu)建企業(yè)數(shù)據(jù)庫。讓我們進下來認識它的四個特征。(4)非易失性：數(shù)據(jù)倉庫是物理地分離存放數(shù)據(jù)；基于這種分法，數(shù)據(jù)倉庫不需要傳輸進程，覆蓋和并發(fā)控制機制。這使得知識工作者能夠利用數(shù)據(jù)倉庫，快捷方便地得到數(shù)據(jù)總體視圖，根據(jù)數(shù)據(jù)倉庫中的信息做出準確的決策。數(shù)據(jù)庫工業(yè)界和研究界都正朝著實現(xiàn)這一目標竭盡全力。對于異種數(shù)據(jù)庫集成的傳統(tǒng)方法，數(shù)據(jù)倉庫提供了一個有趣的替代方案。由于大多數(shù)人都熟悉商品關(guān)系數(shù)據(jù)庫系統(tǒng)，將數(shù)據(jù)倉庫與之比較，就容易理解什么是數(shù)據(jù)倉庫。（1）用戶和系統(tǒng)定位：聯(lián)機事務(wù)處理是以顧客為導(dǎo)向，用于給客戶和信息技術(shù)專家傳輸和職員查詢處理?？偟脕碚f，在線分析系統(tǒng)經(jīng)?？缭皆S多數(shù)據(jù)庫版本，基于組織機構(gòu)的改革。操作數(shù)據(jù)庫是在己知的任務(wù)和負載設(shè)計的，如果用主關(guān)鍵字索引和散列，檢索特定的記錄和優(yōu)化“罐裝”的查詢。最后，從數(shù)據(jù)倉庫中分離數(shù)據(jù)的操作是基于不同的數(shù)據(jù)結(jié)構(gòu)，內(nèi)容和用法。it is numbered 3 in the provides clearance between work and tool so that its cut surface can flow by with minimum rubbing against the save time, a portion of the end flank of the tool may sometimes be left unground, having been previously forged to such case, this endclearance angle, nu