系統(tǒng)的分析與設計外文翻譯

1、引 言如今的世界，已經(jīng)是步入了信息化的時代，特別是互聯(lián)網(wǎng)的迅猛發(fā)展，帶動了信息進入我們生活的各個領域，也使得信息化建設成為各行業(yè)、各領域增強自身管理效率和核心競爭力的重要手段。出版業(yè)作為我國社會主義文化產(chǎn)業(yè)的一部分，在信息化建設方面相對于其他領域，有成績是肯定的，但仍然顯得滯后，建設水平不夠高，離市場需求還有一定距離，還有很大的發(fā)展?jié)摿?，在我國信息化建設中應該發(fā)揮更大的作用。同時要充分利用先進的電子信息技術改造出版業(yè)，來加快出版業(yè)信息化建設的步伐。出版社信息化建設是用一種全新的、先進的管理理念，一種全新的機制，一種全新的企業(yè)文化來改變以前的管理模式，是一種管理模式的變革。它充分利用信息技術與出

2、版社管理模式的結合，來推動管理水平的提升。面對日益激烈的競爭，出版社必須轉變思路，確立全新的經(jīng)營理念，確立以讀者需求為中心，提供專業(yè)化的一流服務。信息化建設更是一場管理體制的革命，它要用先進的思想模式和技術手段改變以前的管理模式，用數(shù)字化、規(guī)范化、程序化、標準化來進行管理，用量化的指標支持獎懲與分配政策，體現(xiàn)激勵機制。通過這場改革和革命，最終實現(xiàn)出版社的辦公自動化、管理網(wǎng)絡化、資源數(shù)字化、商務電子化。而在整個的出版過程中，編務管理是出版行業(yè)信息管理系統(tǒng)的重要部分,它將編務人員及圖書管理人員從繁重的事務性工作中解放出來,并使管理工作更透明、更科學,此次的系統(tǒng)如果有了良好的分析與設計,不但對編務管

3、理,而且對整個出版行業(yè)的管理信息系統(tǒng)的建設都具有十分重要的意義。本文將以北京科學技術出版社為例，為出版企業(yè)編務管理部門的信息化建設提出一個可行性方案，為將來的出版社進行信息化建設打下良好的基礎。附錄1 外文翻譯(原文)systems analysis and design working under control of a stored program, a computer processes data into information. think about that definition for a minute. any given computer application inv

4、olves at least three components: hardware, software, and data. merely writing a program isnt enough; because the program is but one component in a system.a system is a group of components that work together to accomplish an objective. for example, consider a payroll system. its objective is paying e

5、mployees. what components are involved? each day，employees record their hours worked on time cards. at the end of each week, the time cards are collected and delivered to the computer center, where they are read into a payroll program. as it runs, the program accesses data files. finally, the payche

6、cks are printed and distributed. for the system to work, people, procedures, input and output media, files, hardware, and software must be carefully coordinated. note that the program is but one component in a system.computer-based systems are developed because people need information. those people,

7、 called users, generally know what is required, but may lack the expertise to obtain it. technical professionals, such as programmers, have the expertise, but may lack training in the users field. to complicate matters, users and programmers often seem to speak different languages, leading to commun

8、ication problems. a systems analyst is a professional who translates user needs into technical terms, thus serving as a bridge between users and technical professionals.like an engineer or an architect, a systems analyst solves problems by combining solid technical skills with insight, imagination,

9、and a touch of art. generally, the analyst follows a well-defined, methodical process that includes at least the following steps;1. problem definition2. analysis3. design4. implementation 5. maintenanceat the end of each step, results are documented and shared with both the user and the programmers.

10、 the idea is to catch and correct errors and misunderstandings as early as possible. perhaps the best way to illustrate the process is through example.picture a small clothing store that purchases merchandise at wholesale, displays this stock, and sells it to customers at retail. on the one hand, to

11、o much stock represents an unnecessary expense. on the other hand, a poor selection discourages shoppers. ideally, a balance can be achieved: enough, but not too much.complicating matters is the fact that inventory is constantly changing, with customer purchases depleting stock, and returns and reor

12、ders adding to it. 1 the owner would like to track inventory levels and reorder and given item just before the store runs out. for a single item, the task is easy-just count the stock-on-hand. unfortunately, the store has hundreds of different items, and keeping track of each one is impractical. per

13、haps a computer might help.2-1 problem definitionthe first step in the systems analysis and design process is problem definition. the analysts objective is determining what the user (in this case, the stores owner) needs. note that, as the process begins, the user possesses the critical information,

14、 and the analyst must listen and learn. few users are technical experts. most see the computer as a magic box, and are not concerned with how it works. at this stage, the analyst has no business even thinking about programs, files, and computer hardware, but must communicate with the user on his or

15、her own term.the idea is to ensure that both the user and the analyst are thinking about the same thing-thus, a clear, written statement expressing the analysts understanding of the problem is essential. the user should review and correct this written statement. the time to catch misunderstandings a

16、nd oversights is now, before time, money and effort are wasted.often, following a preliminary problem definition, the analyst performs a feasibility study. the study a brief capsule version of the entire systems analysis and design process, attempts to answer three questions:1. can the problem be so

17、lved?2. can it be salved in the users environment?3. can it be solved at a reasonable cost?if the answer to any one of these questions is no, the system should not be developed. given a good problem definition and a positive feasibility study, the analyst can turn to planning and developing a proble

18、m solution.2- 2 analysisas analysis begins, the analyst understands the problem. the next step is determining what must be done to solve it. the user knows what must be done 1 during analysis; this knowledge is extracted and formally documented. most users think in terms of the functions to be perfo

19、rmed and the data elements to be manipulated. the objective is to identify and link these key functions and data elements, yielding a logical system design.start with the systems basic functions. the key is keeping track of the stock-on-hand for each product in inventory. inventory changes because c

20、ustomers purchase, exchange, and return products, so the system will have to process customer transactions. the stores owner wants to selectively look at the inventory level for any product in short supply and, if appropriate, order replacement stock, so the system must be able to communicate with m

21、anagement. finally, following management authorization, the system should generate a reorder ready to send to a supplier.fig 1given the systems basic functions, the analysts next task is gaining a sense of their logical relationship. a good way to start is by describing how data flow between the fun

22、ctions. as the name implies, data flow diagrams are particularly useful for graphically describing these data flows. four symbols are used (fig. 1). data sources and destinations are represented by squares; input data enter the system from a source, and output data flow to a destination. once in the

23、 system, the data are manipulated or change by processes, represented by round-corner rectangles. a process might be a program, a procedure, or anything else that changes or moves data. data can be held for later processing in data stores, symbolized by open-ended rectangles. a data store might be a

24、 disk file, a tape file, a database, written notes, or even a persons memory. finally, data flow between sources, destinations, processes, end data stores over data flows, which are represented by arrows.fig 2figure 2 shows a preliminary data flow diagram for the inventory system. start with custome

25、r. transactions flow from a customer f into the system, where they are handled by process transaction. a data store, stock, holds data on each item in inventory. process transaction changes the data to reflect the new transaction. meanwhile, management accesses the system through communicate, evalua

26、ting the data in stock and, if necessary, requesting a reorder. once, a reorder is authorized. generate reorder sends necessary data to the supplier, who ships the items to the store. note that, because the reorder represents a change in the inventory level of a particular product or products it is

27、handled as a transaction.the data flow diagram describes the logical system. the next step is tracing the data flows. start with the destination supplier. reorders flow to suppliers; for example, the store might want 25 pairs of jeans. to fill the order, the supplier needs the product description an

28、d the reorder quantity. where do these data elements come from? since they are output by generate reorder, they must either be input to or generated by this process. data flow into generate reorder for stock; thus, product descriptions and reorder quantities must be stored in stock.other data elemen

29、ts, such as the item purchased and the purchase quantity are generated by customer. still others, for example selling price and reorder point, are generated by or needed by management. the current stock-on-hand for a given item is an example of a data element generated by an algorithm in one of the

30、procedures. step by step, methodically, the analyst identifies the data elements to be input to .stored by, manipulated by, generated by, or output by the system.to keep track of the data elements, the analyst might list each one in a data dictionary. a simple data dictionary can be set up on index

31、cards, but computerized data dictionaries have become increasingly popular. the data dictionary, a collection of data describing and defining the data, is useful throughout the systems analysis and design process, and is often used to build a database during the implementation stage.the idea of anal

32、ysis is to define the systems major functions and data elements methodically. remember that the objective is translating user needs into technical terms. since the system starts with the user, the first step is defining the users needs. users think in terms of functions and data. they do not visuali

33、ze programs, or files, or hardware .and during this initial, crucial analysis stage it is essential that the analyst think like a user, not like a programmer.data flow diagrams and data dictionaries are useful tools. they provide a format for recording key information about the proposed system. also

34、, they jog the analysts memory) for example, if the analyst doesnt have sufficient information to complete a data dictionary entry, he or she has probably missed something. perhaps most importantly, the data flow diagram and the data dictionary document the analysts understanding of the system requi

35、rements. by reviewing these documents, the user can correct misunderstandings or oversights. finally, they represent an excellent starting point the next step, design.2-3 designas we enter the design stage, we know what the system must do, and thus can begin thinking about how to do it. the objectiv

36、e is to develop a strategy for solving the problem. at this stage, we are not interested in writing code or in defining precise data structures; instead, we want to identify, at a black box level, necessary programs, files, procedures, and other components.the data flow diagram defines the systems n

37、ecessary functions; how might they be implemented? one possibility is writing one program for each process. another is combining two or more processes in a single program; there are dozens of alternative solutions. lets focus on one option and document it.a system flowchart uses symbols to represent

38、 programs, procedures, hardware devices, and the other components of a physical system (fig. 3). our flowchart (.fig. 4) shows that transaction data enter the system through a terminal, are processed by a data collection program, and then are stored on an inventory file. eventually, the inventory fi

39、le is processed by a report and reorder program. through it, management manipulates the data and authorizes reorders.fig. 4 on a system flowchart, symbols represent programs, procedures, hardware devices, and the other components of a physical system.fig 3look at the system flowchart. it identifies

40、several hardware components, including a computer, a disk drive, a data entry terminal, a printer, and a display terminal. two programs are needed; process transaction and report and reorder. in addition to the hardware and the programs, well need data structures for the inventory file and for data

41、flaws between the i/o devices and the software. note that this system flowchart illustrates one possible solution; a good analyst will develop several feasible alternatives before choosing one.fig 4the flowchart maps the system, highlighting its major physical components. since the data link the com

42、ponents, the next task is defining the data structures. consider, for example, the inventory file. it contains all the data elements from the data store stock. the data elements are listed in the data dictionary. using them, the files data structure can be planned,how should the file be organized? t

43、hat depends on how it will be accessed. for example, in some applications, data are processed at regular, predictable intervals. typically, the data are collected over time and processed together, as a batch. if batch processing is acceptable, a sequential file organization is probably best.it is no

44、t always possible to wait until a batch of transactions is collected, however. for example, consider an air defense early warning system. if an unidentified aircraft is spotted it must be identified immediately the idea of waiting until 5 _ 00 p.m. because thats when the air defense program is run i

45、s absurd. instead, because of the need for quick response, each transaction must be processed as it occurs. generally such transaction processing systems call for direct access file.our inventory system has two programs. one processes transactions. a direct access inventory file seems a reasonable c

46、hoice. the other allows management to study inventory data occasionally; batch processing would certainly do. should the inventory file be organized sequentially or directly? faced with such a choice a good analyst considers both options. one possible system might accept transactions and process the

47、m as they occur. as an alternative, sales slips might be collected throughout the day and processed as a batch after the store closes. in the first system, the two programs would deal with direct access files; in the second system, they would be linked to sequential files. a program to process direc

48、t access data is different from a program to process sequential data. the data drive the system. the choice of a data structure determines the programs structure. note that the program is defined and planned in the context of the system.2- 4 implementationonce the systems major components have been

49、identified .we can begin to develop them. our system includes two programs, several pieces of equipment, and a number of data structures. during implementation, each program is planned and written using the techniques described in chapter 7. files are created, and their contents checked. new hardwar

50、e is purchased, installed, and tested. additionally, operating procedures are written and evaluated. once all the component parts are ready, the system is tested. assuming the user is satisfied, the finished system is released.2- 5 maintenancemaintenance begins after the system is released. as peopl

51、e use it, they will suggest minor improvements and enhancements. occasionally, bugs slip through debug and testing, and removing them is another maintenance task. finally, conditions change, and a program must be updated; for example, if the government passes a low changing the procedure for collect

52、ing income taxes, the payroll program must be modified. maintenance continues for the life of a system, and its cost can easily match or exceed the original development cost. good planning, solid documentation, and well-structured programs can help to minimize maintenance cost.附錄2 外文翻譯(譯文)系統(tǒng)的分析與設計 在

53、存儲程序的控制下，計算機把數(shù)據(jù)處理成信息。對系統(tǒng)的定義略加思考，任何一個已知的計算機應用至少包含三個部分，硬件、軟件和數(shù)據(jù)。僅僅編寫一個程序是不夠的，因為程序只是系統(tǒng)中的一部分。 系統(tǒng)就是為實現(xiàn)一個目標而共同工作的一組部件。例如，考慮一個工資系統(tǒng)，它的目標是為雇員付工資，應包含哪幾部分呢？每天雇員們把他們工作的時數(shù)記錄在計時卡片上，每周末把計時卡片收集起來，送給計算中心，在計算中心把計時卡片上的數(shù)據(jù)讀給工資程序。當工資程序執(zhí)行時，程序存取數(shù)據(jù)文件。最后，打印出工資單，用來分發(fā)。為使系統(tǒng)工作，人、處理過程、輸入和輸出介質、文件、硬件和軟件都必須認真地協(xié)調(diào)。注意，程序只是系統(tǒng)中的一部分。 因為人們

54、需要信息，所以要開發(fā)基于計算機的系統(tǒng)。被稱為用戶的那些人常常知道需求什么信息，但是他們可能缺乏得到這些信息的計算機的專門知識。計算機技術方面的專業(yè)人員，例如程序設計員有這方面的專門知識，但是可能在用戶的專業(yè)領域內(nèi)缺少訓練。麻煩的是。用戶和程序員似乎常常講不同的語言，導致了兩者之間的聯(lián)系障礙。系統(tǒng)分析員是一個專業(yè)人員，他能把用戶的需求轉換成計算機技術術語。因此他是用戶和技術專業(yè)人員之間的橋梁。 像工程師或建筑師一樣，系統(tǒng)分析員把他扎實的技術技能與知識、想象力和一點藝術結合起來去解決問題通常，分析員遵循一個意義明確的有條理的過程，至少應包括以下幾個步驟： 1問題的定義 2分析 3設計 4實現(xiàn) 5維

55、護 在每一步驟的結尾，研究的結果都要形成文件，提供給用戶和程序設計員?；镜乃枷胧且M早地抓住和修正錯誤以及一些未理解之處。也許通過一個例子來說明該過程是最好的方法。 設想一個小服裝店，成批地購買貨物，把貨物擺在貨架上，零售給顧客。一方面庫存太多會造成不必要的開銷；另一方面可供挑選的商品太少會使顧客失去購買的信心。理想上，希望達到一個平衡，貨物即充足但又不太多。麻煩的是，隨著顧客的購買庫存減少了，還有退貨以及追加訂貨等情況，所以貨物的清單經(jīng)常地發(fā)生變化店主喜歡按貨物清單購銷，剛好在商店售完某種貨物之前，再訂購這種貨。對一項商品，該任務是容易完成的，只要計算一下手頭現(xiàn)存的貨物數(shù)量就行了。遺憾的是

56、商店要經(jīng)管幾百種不同的貨物，始終跟蹤每一種貨物的銷售情況是不實際的，也許計算機可以幫這個忙吧！2.1問題定義 在系統(tǒng)分析和設計過程中的第一步，是問題的定義。分析員的目標是確定用戶需求什么（本例中就是店主需求什么）。注意，當這個過程開始時，用戶擁有很重要的資料，分析員必須認真地聽和學。用戶幾乎都不是計算機方面的專家，他們大多數(shù)人把計算機看成魔術盒，并不關心它是如何工作的。在該階段上，分析員不必考慮程序、文件或計算機硬件，但他們必須用自己的專業(yè)術語與用戶對話。 目的是確保用戶和分析員兩者都思考同一件事。因此，一份能表達分析員對問題理解程度的清晰的書面報告是必要的。用戶應該反復地閱讀和修改這份書面報

57、告。此時是在時間、金錢和精力被浪費之前抓出錯誤和疏漏的好時機。 通常，接著初步的問題定義，分析員要進行可行性研究。該研究是整個系統(tǒng)分析和設計的一個簡略的方案，應力圖回答以下三個問題： 1問題能解決嗎？ 2在用戶的環(huán)境下問題能解決嗎？ 3在一個合適的花費上問題能解決嗎？如果這些問題中的任何一個得到的是否定回答，那么該系統(tǒng)就不應開發(fā)。有了好的問題定義和肯定的可行性研究，分析員就能著手計劃和研究問題的解了。2.2分析 分析開始時，分析員要理解問題，下一步要決定的是為了解決問題必須做什么。用戶清楚必須做什么。在分析階段礙到了這方面知識，并正式地形成文件。大多數(shù)用戶是按著所要完成的功能和所要處理的數(shù)據(jù)元

58、素去思考的，目的是要區(qū)分并聯(lián)接這些關鍵的功能和數(shù)據(jù)元素，隨之產(chǎn)生邏輯系統(tǒng)設計。 從系統(tǒng)的基本功能入手，關鍵是始終監(jiān)視貨單中每種商品的現(xiàn)存量。因為顧客購買、換貨和退貨，所以貨單要改變，因此系統(tǒng)必須處理顧客辦理的手續(xù)。店主希望有選擇地查看供應中任意一種短缺商品的清單，如果合理的話，定貨補充庫存，因此系統(tǒng)必須能和經(jīng)營管理部門對話。最后，經(jīng)過經(jīng)營管理部門的核準，系統(tǒng)應該產(chǎn)生一個重新訂貨單，準備發(fā)送給供應商。圖 1 已知了系統(tǒng)的基本功能，分析員的下一個任務是分析理解這些功能之間邏輯關系的知識。啟動這項工作的一個好方法是描述功能之間的數(shù)據(jù)如何流動顧名思義，為了用圖解方法描述這些數(shù)據(jù)流，那么數(shù)據(jù)流程圖就是特別有用的圖1中用到四種符號數(shù)據(jù)的像和目的地用方框表示，輸入的數(shù)據(jù)從源進入系統(tǒng)，而輸出的數(shù)據(jù)流到目的地。數(shù)據(jù)一進入系統(tǒng)，就被若干進程加工或改變，用圓角的矩形表示這些過程。進程可以是程序、過程以及能夠改變或傳送數(shù)據(jù)的任何事件為了后續(xù)處理，數(shù)據(jù)被保留在數(shù)據(jù)存儲器內(nèi)，這可用末端開口的矩形符號表示。數(shù)據(jù)存儲可以是磁盤文件、磁帶文件、數(shù)據(jù)庫、一些筆記或者甚至是人的記憶。最后，數(shù)據(jù)源