針對(duì)目前使用的RS232接口數(shù)字化B超鍵盤存在PC主機(jī)啟動(dòng)時(shí)不能設(shè)置BIOS,提出一種PS2鍵盤的設(shè)計(jì)方法。基于W78E052D單片機(jī),采用8通道串行A/D轉(zhuǎn)換器設(shè)計(jì)了8個(gè)TGC電位器信息采集電路,電位器位置信息以鍵盤掃描碼序列形式發(fā)送,正交編碼器信號(hào)通過XC9536XL轉(zhuǎn)換為單片機(jī)可接收的中斷信號(hào),軟件接收到中斷信息后等效處理成按鍵。結(jié)果表明,在滿足開機(jī)可設(shè)置BIOS同時(shí),又可實(shí)現(xiàn)超聲特有功能,不需要專門設(shè)計(jì)驅(qū)動(dòng)程序,接口簡(jiǎn)單,成本低。
Abstract: Aiming at the problem of the digital ultrasonic diagnostic imaging system keyboard with RS232 interface currently used couldn?蒺t set the BIOS when the PC boot, this paper proposed a design method of PS2 keyboards. Based on W78E052D microcontroller,designed eight TGC potentiometers information acquisition circuit with 8-channel serial A/D converter, potentiometer position information sent out with keyboard scan code sequentially.The control circuit based on XC9536 CPLD is used for converting the mechanical actions of the encoders into the signals that can be identified by the MCU, software received interrupt information and equivalently treatmented as key. The results show that the BIOS can be set to meet the boot, ultrasound specific functionality can be achieved at the same time, it does not require specially designed driver,the interface is simple and low cost.
java ejb開發(fā) 程序4、語句alter table people add(phone_number varchar2(10)) 的作用是 A 修改表結(jié)構(gòu) B 為people表添加約束,約束名稱是phone_number C 向people表中添加一列,名稱是phone_number,數(shù)據(jù)類型是varchar2,長(zhǎng)度是10 D 上述答案均不正確 5、( )BLOB和CLOB的區(qū)別在于 A CLOB只能存放字符類型的數(shù)據(jù),而BLOB沒有任何限制 B BLOB只能存放字符類型的數(shù)據(jù),而CLOB沒有任何限制 C CLOB只能存放小于4000字節(jié)的數(shù)據(jù),而BLOB可以存放大于4000字節(jié)的數(shù)據(jù) D BLOB只能存放小于4000字節(jié)的數(shù)據(jù),而CLOB可以存放大于4000字節(jié)的數(shù)據(jù) 6、存儲(chǔ)過程從本質(zhì)上來講就是 A 匿名的PL/SQL程序塊,它可以被賦予參數(shù) B 命名的PL/SQL程序塊,它可以被賦予參數(shù) C 命名的PL/SQL程序塊,不能被賦予參數(shù) D 匿名的PL/SQL程序塊,不能被賦予參數(shù) 7、( )下列關(guān)于日期數(shù)據(jù)類型,哪一個(gè)語句是正確的寫法 A insert into test values( 9999-12-03 ) B insert into test values( 1999-03-02 ) C insert into test values(to_char(1999-06-03, yyyy/dd/mm )) D insert into test
本系統(tǒng)采用A. 系統(tǒng)需求分析報(bào)告(設(shè)計(jì)方法/數(shù)據(jù)流圖/數(shù)據(jù)字典) B. 數(shù)據(jù)庫的信息要求報(bào)告(E—R圖及關(guān)系數(shù)據(jù)模型) C. 數(shù)據(jù)庫的操作和應(yīng)用要求報(bào)告(模塊結(jié)構(gòu)圖<概念結(jié)構(gòu)設(shè)計(jì)及邏輯結(jié)構(gòu)設(shè)計(jì)>) D. 調(diào)試中出現(xiàn)的問題及解決方法(物理設(shè)計(jì),調(diào)試及運(yùn)行,維護(hù)) E. 訪問數(shù)據(jù)庫的方式(ODBC,
Floyd-Warshall算法描述
1)適用范圍:
a)APSP(All Pairs Shortest Paths)
b)稠密圖效果最佳
c)邊權(quán)可正可負(fù)
2)算法描述:
a)初始化:dis[u,v]=w[u,v]
b)For k:=1 to n
For i:=1 to n
For j:=1 to n
If dis[i,j]>dis[i,k]+dis[k,j] Then
Dis[I,j]:=dis[I,k]+dis[k,j]
c)算法結(jié)束:dis即為所有點(diǎn)對(duì)的最短路徑矩陣
3)算法小結(jié):此算法簡(jiǎn)單有效,由于三重循環(huán)結(jié)構(gòu)緊湊,對(duì)于稠密圖,效率要高于執(zhí)行|V|次Dijkstra算法。時(shí)間復(fù)雜度O(n^3)。
考慮下列變形:如(I,j)∈E則dis[I,j]初始為1,else初始為0,這樣的Floyd算法最后的最短路徑矩陣即成為一個(gè)判斷I,j是否有通路的矩陣。更簡(jiǎn)單的,我們可以把dis設(shè)成boolean類型,則每次可以用“dis[I,j]:=dis[I,j]or(dis[I,k]and dis[k,j])”來代替算法描述中的藍(lán)色部分,可以更直觀地得到I,j的連通情況。