外文翻譯--低成本實(shí)時(shí)智能計(jì)價(jià)器傳感器

1、<p>　　中文3255字，1965單詞</p><p><b>　　英文翻譯</b></p><p>　　下屬學(xué)院 理工學(xué)院 </p><p>　　專 業(yè) 電子信息工程 </p><p>　　班 級(jí) <

2、;/p><p>　　2012 年 3 月 8日</p><p>　　<文獻(xiàn)翻譯一：原文></p><p>　　A LOW COST REAL-TIME INTELLIGENT TAXIMETER SENSOR</p><p><b>　　ABSTRACT</b></p><p>　　A t

3、aximeter smart sensor system possessing immunity to fraud is introduced. The system is based upon embedded controllers employed to perform the crypto-operation between the sensor and taximeter using the standard RC5 algo

4、rithm. Special emphasis is given to promote highest system integrity while keeping complexity, size and cost to minimum. Preliminary practical implementation and verification of the system installed and tested under real

5、 taxicab environment promises its feasibility to cope wit</p><p>　　INTRODUCTION</p><p>　　For more than a decade, taximeter has been conceived as a ubiquitous device that allows cap passengers in

6、 big cities around the globe to avoid the hassle of begin overcharged. Practically all the meters implemented these days, are based upon micro-controller systems. To process taxi fares, a motion sensor (such as a Hall-ef

7、fect device) is installed between the gearbox and speedometer and whenever the vehicle is in motion it generates electrical pulses to the micro-controller based taximeter for </p><p>　　In fact, the integrity

8、 of the current taximeters has so long been in question due to the fact that the adopted system in use nowadays exhibits a critical loophole that may cause unreliability and allow faulty operation. The drawback is the sy

9、stem susceptibility to interference either created by the nearby engine or artificially induced. This interference coupling onto the pulse cable routing between the sensor and the taximeter produces additional pulses sup

10、erimposed on the original sensor signa</p><p>　　To combat the pitfall, a real-time intelligent taximeter sensor system immune to the interference or fraud pulses is developed in this paper. The principal and

11、 detailed operations of the proposed system are outlined. Issues concerning synchronisation and implementation are also addressed. Finally, practical results and testing of the smart system in real environment are discus

12、sed.</p><p>　　SYSTEM OVERVIEW</p><p>　　The overall block diagram of the introduced system is shown in Fig. 1. Essentially, the principle behind the development is to embed a small micro-controll

13、er into the sensor to allow the encryption of the sensor’s pulse stream before being transmitted along the routing cable. At the other end, another micro-controller of a similar type is also introduced to enable the decr

14、yption of the encrypted pulses. Principally, any type of encryption algorithms can be employed but the obvious criterion is t</p><p>　　The proposed encryption process relies on the sampling of the original p

15、ulses over a chosen period by the encryption or transmitting controller. Subsequently, two sets of data are generated by encrypting the sampled pulses using two unique keys (denoted as A and B in Fig.1). For our designed

16、 system, key A and key B are selected pseudo-randomly from a set of 16 unique keys for good security, The resulting pair of encrypted data is then transmitted sequentially to the decryption or receiving contr</p>

17、<p>　　DETAILED OPERATION AND TRANSMISSION PROTOCOL</p><p>　　Most of the pre-installed sensors for taxis in the designated Bangkok metropolitan area typically output the pulse steam at the maximum of 6,7

18、50 pulses per km.If the highest car speed is limited to 200 km/hr, the shortest pulse period released is 2.67ms. This has been rounded down to 2ms giving the maximum pulse frequency of 500Hz.</p><p>　　Illust

19、rated in Fig.2 is the detailed transmission operation of the encryption controller where the original pulse stream from sensor is sampled at the intervals of 250us using the controller’s interrupts. The intervals between

20、 each interrupt are denoted as “Slot”. The RC5 algorithm employed requires 16 sampled pulses per one encryption and this sets the number of slots in one transmitting cycle (and the receiving cycle) to 16 indicated as Slo

21、t 0 to Slot 15 in Fig2 and thus the period per one cyc</p><p>　　The transmitter begins with idle state at Slot 0. During Slot 2 and 4, the stored 16-bit sensor data sampled in the previous operating cycle is

22、 encrypted using the pre-assigned key A and key B respectively, resulting in two sets of 16-bit encrypted data. Each key is 64-bit long and is selected in a pseudo-random fashion from the total of 16 unique keys. The res

23、ulting RC5-encrypted data is subsequently arranged into four collections of 8-bit data before being transmitted along with the associated</p><p>　　At the decryption controller, after the synchronizing data h

24、as been detected, its internal timer will be enabled to generate 16 interrupts every 250us to output to the to taximeter the decrypted data pulses that has been stored in a designated 16-bit buffer in the previous cycle.

25、Again at this receiving end, the interval between each interrupt is denoted as “Slot” and there are 16 slots per one receiving cycle as depicted in detail in Fig.4. The four 8-bit blocks of data arriving at Slot 3, 5 , 9

26、</p><p>　　SYNCHRONISATION</p><p>　　Due to the inevitable small discrepancy between the clock time base and the two ends, the smart sensor system necessitates a periodic synchronisation to preven

27、t missing of the transmitted data. As explained in the last section,this is achieved by enabling the transmitter to send an agreed data pattern to initiate the receiving operation in the receiver for every operating cycl

28、e. In the system, the pattern of the synchronising data is 10-bit long and its slot frame is similar to that in Fig.3. Fo</p><p>　　EXPERIMENTAL RESULTS OF THE SYSTEM PROTOTYPE</p><p>　　The descr

29、ibed smart taxi-meter sensor has been implemented and tested to demonstrate the practical utilisation of such system for taxis operating within Bangkok metropolitan area. The real-time intelligent sensor system has been

30、implemented using a pair of small and inexpensive micro-controllers, PIC16F84 [7],from the micro-chip company. They are clocked at 8MHz for both the encryption and decryption ends with a few external components. The cont

31、roller for encryption is attached on to the existin</p><p>　　Fig. 6(a). shows the measured waveforms for a complete operating cycle of the system. Note that the cycle occupies a time period of 4ms. Without t

32、he indicated vertical traces, it is virtually impossible to identify the starting and ending of one transmission cycle and this provides system robustness to possible code-breaking attack With no interference introduced

33、into the transmission cable, the tested random data at both ends exactly matches to each other, as illustrated in Fig. 6(b). Also noti</p><p>　　For a thorough test under real operation, the prototyped system

34、 has been installed in 10 local taxicabs in Bangkok for more than two months. So far, there has been no report of faulty operation.</p><p>　　CONCLUSION</p><p>　　The taximeter system utilising sm

35、all and inexpensive controllers to prevent fraud has been developed. The proposed system relies on the crypto-operation between the pulses emanated from the speed sensor and the taximeter to provide a high immunity to fa

36、ked pulse deliberately injected along the routing cable. Superior integrity and security are assured by concealing repetitive transmission patterns in the system’s operating cycle. Based upon the principle, a practical s

37、ystem has been constructed </p><p>　　REFERENCES</p><p>　　[1] S.Jantarang and S.Pookaiyaudoom. “Taximeter”. APHEIT Journal, pp.16-18, 1994</p><p>　　[2] S.Jantarang.“Taximeter Tester”

38、. EECON’ 17, pp.390-393, 1994</p><p>　　[3] Ronald L. Rivest. “The RC5 Encryption Algorithm”. MIT Laboratory Computer Science, 1997</p><p>　　[4] BSchneier. “Applied Cryptography”. John Wiley &

39、; Sons, Inc., pp.344-346, 1996.</p><p>　　[5] SSaipankeaw and SJantarang. “RC5 Encryption Using FPGA”. Proceedings of NCSEC 2000, 16-17 Nov. 2000.</p><p>　　[6] SSaipankeaw and S.Jantarang. “High

40、Speed Image Encryption Using FPGA”. Proceedings of NCSEC 2000, 16-17 NOV. 2000.</p><p>　　[7] Microchip Inc. “PIC16/17 Data Book”. Microchip Inc., 1996</p><p>　　<文獻(xiàn)翻譯一：譯文></p><p

41、>　　低成本實(shí)時(shí)智能計(jì)價(jià)器傳感器</p><p><b>　　文摘</b></p><p>　　本文介紹了一個(gè)具有免疫欺詐的出租車計(jì)價(jià)器智能傳感器系統(tǒng)。該系統(tǒng)是基于嵌入式控制器在傳感器和出租車計(jì)價(jià)器之間使用了標(biāo)準(zhǔn)的RC5算法，用來執(zhí)行加密操作。特別強(qiáng)調(diào)了在保持最高系統(tǒng)完整性的前提下,促進(jìn)復(fù)雜、尺寸和成本降到最低。初步的具體實(shí)現(xiàn)和驗(yàn)證系統(tǒng)的安裝調(diào)試環(huán)境承諾在真實(shí)的

42、計(jì)程車其可行性應(yīng)對(duì)欺詐處理的車費(fèi)。</p><p><b>　　1.介紹</b></p><p>　　十多年來, 出租車計(jì)價(jià)器已被視為無所不在的設(shè)備,它可以讓全世界大城市的乘客避免被過度收費(fèi)的麻煩。特別是如今所使用的儀表,都是基于單片機(jī)系統(tǒng)。處理計(jì)程車費(fèi),運(yùn)動(dòng)傳感器(如霍爾器件安裝變速箱和測(cè)速儀之間,每當(dāng)車輛在運(yùn)動(dòng)產(chǎn)生電脈沖的微控制器為基礎(chǔ)出租車計(jì)價(jià)器費(fèi)用計(jì)算。產(chǎn)生脈

43、沖流的周期是與車輛瞬時(shí)速度成反比的及實(shí)際比例常量取決于汽車類型。所以,傳感器一定時(shí)間間隔釋放出來的脈沖數(shù)影響所經(jīng)過的距離,而這距離是計(jì)價(jià)器用來計(jì)算車費(fèi)的[1,2]。</p><p>　　事實(shí)上,目前的完整性出租車計(jì)價(jià)器長(zhǎng)久以來就是個(gè)問題,由于這樣的事實(shí),即采用的系統(tǒng)在使用中一個(gè)非常重要的漏洞,可能導(dǎo)致不可靠性和不當(dāng)操作。缺點(diǎn)是系統(tǒng)會(huì)被干擾或由附近的引擎或人工誤操作干擾。這種干擾耦合到脈沖之間的電纜路由的傳感器和計(jì)

44、價(jià)器產(chǎn)生額外的脈沖信號(hào)疊加在原始傳感器。在這種方式下,一些假的脈沖某一時(shí)刻被創(chuàng)造出來并沿著電纜路由能有效地提高系統(tǒng)的車費(fèi)使易于欺詐。</p><p>　　為了對(duì)抗這種圈套，在這篇文章中一種實(shí)時(shí)智能免疫傳感器系統(tǒng)的干擾脈沖或欺詐的計(jì)價(jià)器開發(fā)了。這個(gè)系統(tǒng)最重要且最精細(xì)的操作的大概輪廓已經(jīng)清楚了。有關(guān)問題的提出和實(shí)現(xiàn)同步也進(jìn)行了處理。最后,實(shí)際結(jié)果和智能系統(tǒng)在真實(shí)的環(huán)境的測(cè)試問題進(jìn)行了探討。</p>&l

45、t;p><b>　　2.系統(tǒng)概述</b></p><p>　　這個(gè)系統(tǒng)的總體框圖已經(jīng)展示在圖1中。從本質(zhì)上講,背后的理念發(fā)展成一個(gè)小控制器嵌入傳感器允許加密技術(shù)的傳感器的脈沖流被傳輸之前沿著路由電纜。在另一方面,另一個(gè)相似類型微控制器用來解密加密的脈沖。最主要的是,任何類型的加密算法可能被使用到,但明顯的準(zhǔn)則是選擇一個(gè),給硬件帶來的負(fù)擔(dān)最小,同時(shí)提供可接受的安全水平。</p>

46、;<p>　　該加密過程依賴于原脈沖在選擇加密或傳輸控制器的采樣時(shí)期。隨后,兩組數(shù)據(jù)樣本使用兩個(gè)獨(dú)特的信息產(chǎn)生脈沖加密（在圖1中用鑰匙A和鑰匙B表示）。我們?cè)O(shè)計(jì)的系統(tǒng),A和B從一堆16獨(dú)特的鑰匙隨即選擇出,這樣便有了良好的安全,由此產(chǎn)生的對(duì)加密后的數(shù)據(jù)用這些關(guān)鍵號(hào)碼傳輸,然后順序解密或接收控制器。有了指定的信息A和B,在接收端能夠重建進(jìn)來的數(shù)據(jù)集。如果沒有任何信息通過沿著傳輸線纜失真,兩套重建脈沖將完美匹配,其中一個(gè)將被送

47、到計(jì)價(jià)器進(jìn)一步的費(fèi)用計(jì)算。然而, 檢測(cè)兩種重建脈沖之間若有有任何差異,輸出到計(jì)價(jià)器會(huì)被保持在邏輯“0”終止了增加的費(fèi)用用來說明車輛時(shí)固定未動(dòng)的。最終,整個(gè)過程重復(fù)為傳輸控制器下一次的取樣脈沖。</p><p>　　3.詳細(xì)的操作和傳輸協(xié)議</p><p>　　大多數(shù)的出租車預(yù)裝的傳感器,用于指定曼谷大都市地區(qū)，典型的輸出脈沖流最高的6750次脈沖每公里。如果最高的汽車速度限制在200公里每

48、小時(shí),最短脈沖周期2.67毫秒。這已經(jīng)被四舍五入到2毫秒，也就是最大脈沖頻率為500赫茲。因此,取樣頻率將采樣周期超過4千赫(250微秒的采樣周期),超過赫茲奈奎斯特判據(jù)。硬件復(fù)雜度和安全水平的平衡點(diǎn)是使用標(biāo)準(zhǔn)RC5的加密算法[3,4]。</p><p>　　圖2很詳細(xì)地說明了利用控制器的中斷, 采樣250微秒的采樣周期，從傳感器的原脈沖流加密控制器的傳輸操作。每一個(gè)中斷的間隔來為“槽”。算法采用的RC5需要16

49、采樣脈沖來完成每一個(gè)加密和這一規(guī)定隙的數(shù)量在一個(gè)傳輸周期(和接收周期)以16顯示從槽0到槽15,從而每一個(gè)周期是4毫秒。</p><p>　　發(fā)射機(jī)起始于槽0空閑狀態(tài)時(shí)。在槽2和4儲(chǔ)藏的16位在前一個(gè)采樣周期被加密的傳感器的數(shù)據(jù)分別預(yù)先作為鑰匙A和鑰匙B,導(dǎo)致有兩套16位加密的數(shù)據(jù)。每個(gè)鑰匙都是64位長(zhǎng)以及從所有的16把獨(dú)特的鑰匙偽隨機(jī)挑選出來。結(jié)果RC5被加密的數(shù)據(jù)和相關(guān)的鑰匙(0-15) 隨后在被傳輸?shù)轿挥诓?/p>

50、3、5、9、11的接收控制器之前分成4個(gè)采集的8位數(shù)據(jù)。圖3顯示了每個(gè)傳輸槽的數(shù)據(jù)框架,從起始位,緊隨其后的是(高或低的字節(jié))8位加密數(shù)據(jù),(高或低字節(jié))2位的關(guān)鍵號(hào)碼,以終止位結(jié)束。數(shù)據(jù)傳輸速率是100 千位 /秒。促進(jìn)二者之間的同步結(jié)束后,一個(gè)數(shù)據(jù)在槽6同時(shí)產(chǎn)生。在完成傳輸周期之前,同步數(shù)據(jù)就轉(zhuǎn)到接受末端的控制器,在槽15將解密操作的開始排列為一行,接著接收端傳送結(jié)束。下一個(gè)部分將詳細(xì)討論同步操作。從圖2,我們可以看出其它的槽,雖然

51、沒有積極被用在主要操作上,他們被分配去填補(bǔ)周期,要么釋放模擬數(shù)據(jù)(槽1—7和13)或處于空閑(槽10、12、14)。這在很大程度上有助于偽裝一個(gè)結(jié)束的傳輸框架的重復(fù)模式,從而有利于提高安全性。</p><p>　　在解密控制器數(shù)據(jù)同步被檢測(cè)到之后,其內(nèi)部定時(shí)器每250微秒將能夠產(chǎn)生16個(gè)中斷輸出的脈沖計(jì)價(jià)器，解密后的數(shù)據(jù)脈沖流是在上個(gè)周期儲(chǔ)存在指定的16位緩沖區(qū)中。同樣在這個(gè)接收末端,每一個(gè)中斷的間隔被定義為“槽

52、”, 一個(gè)接收周期中共有16個(gè)槽，就像圖4中詳細(xì)的描述的。四個(gè)8位數(shù)據(jù)塊到達(dá)插槽3、5、9、11(符合那些傳輸結(jié)束的槽)存放。數(shù)據(jù)也隨之在槽13和槽14,利用提取的鑰匙A和鑰匙B(映射的鑰匙編號(hào)和加密數(shù)據(jù)被做成獨(dú)一無二的預(yù)設(shè)的16鑰匙表)被解密。在槽15,產(chǎn)生的兩個(gè)解密后的16位二進(jìn)制數(shù)據(jù)進(jìn)行對(duì)比,只有當(dāng)他們是相同的,該數(shù)據(jù)才被釋放來指定16位緩沖,隨后在接下來的周期傳送給計(jì)價(jià)器。然而,如果數(shù)據(jù)不匹配,邏輯“0”將會(huì)把整個(gè)緩沖區(qū)，凍結(jié)費(fèi)

53、用。在槽15末,直到從發(fā)射機(jī)檢測(cè)到同步信號(hào),中斷都會(huì)被禁用,然后整個(gè)接收周期重復(fù)。</p><p><b>　　4.同步</b></p><p>　　由于時(shí)基和兩頭不可避免的小差異,智能傳感器系統(tǒng)需要做到周期同步來防止傳輸數(shù)據(jù)失蹤。正如前面最后一段所解釋的,達(dá)到這個(gè)目標(biāo)可以在每一個(gè)操作周期發(fā)送一種允許的發(fā)射機(jī)數(shù)據(jù)模式來啟動(dòng)接收機(jī)的接收操。在這個(gè)系統(tǒng)里，數(shù)據(jù)同步的模式是

54、10位長(zhǎng)的，他的的槽架構(gòu)與圖3中相似。每個(gè)完整的傳輸操作,另一組的同步數(shù)據(jù)是為了確保安全,這是由2 x16位加密數(shù)據(jù)在每一個(gè)操作周期產(chǎn)生的數(shù)據(jù)來實(shí)現(xiàn)的,使用單一預(yù)算法分配到兩側(cè)。值得注意的是,接收器開始其運(yùn)行, 從發(fā)射機(jī)檢測(cè)到的同步信號(hào)必須與收到的加密數(shù)據(jù)局部相一致(在槽12)。如果這無論如何都沒有通過,收件器將使線路控制(圖5)從而縮短到地面的整個(gè)傳輸線纜和因此最終線路狀態(tài)輸入處于發(fā)射機(jī),兩端的控制器,維持他們的空閑狀態(tài)4 毫秒(一個(gè)

55、完整的操作周期)。</p><p>　　5.實(shí)驗(yàn)結(jié)果的系統(tǒng)原型</p><p>　　所描述的出租車智能傳感器已經(jīng)實(shí)現(xiàn)，且已在曼谷大都市地區(qū)測(cè)試?yán)迷撓到y(tǒng)的實(shí)際操作。實(shí)時(shí)智能傳感器系統(tǒng)用微控制芯片公司一對(duì)小而且便宜的微控制器已經(jīng)被實(shí)現(xiàn), PIC16F84[7]。他們用8兆赫作為時(shí)鐘和一些外部組件對(duì)加密和解密的結(jié)束。該加密控制器依靠現(xiàn)有不完善的傳感器，而解密控制器也只是簡(jiǎn)單地安裝的出租車計(jì)價(jià)器

56、右內(nèi)保持最低化修改整個(gè)系統(tǒng)。</p><p>　　圖6(a)，實(shí)測(cè)波形顯示為系統(tǒng)一個(gè)完整的操作周期。需要注意的是,一個(gè)時(shí)間周期為4毫秒。沒有表明垂直痕跡,實(shí)際上是不可能的識(shí)別一個(gè)傳輸周期系統(tǒng)的開始和結(jié)束,而這使得系統(tǒng)可能在不干擾引入傳輸線纜的情況下的攻擊與破解具有魯棒性,測(cè)試隨機(jī)數(shù)據(jù)兩端彼此完全相同,如圖6(b)。從這個(gè)數(shù)字也注意到數(shù)據(jù)傳輸存在一個(gè)潛在的8個(gè)毫秒的延遲,但這不是問題因?yàn)槠眱r(jià)計(jì)算依賴傳入超過一定時(shí)間

57、間隔的脈沖數(shù)。此外,脈沖重建的延遲,因而票價(jià)計(jì)算只是一小段時(shí)間,使其對(duì)旅客透明化。該系統(tǒng)還使用了500赫茲脈沖信號(hào)進(jìn)行測(cè)試(最大頻率的起源來自速度傳感器),在原傳感器脈沖隨著在接收者的重建的脈沖，如圖6(c)。每當(dāng)故意附加注入一些脈沖到電纜中，接收控制器將不產(chǎn)生脈沖,從而確定系統(tǒng)的功能。</p><p>　　為了在實(shí)際運(yùn)作中詳盡的測(cè)試,原系統(tǒng)已經(jīng)安裝在曼谷當(dāng)?shù)?0輛出租車在兩個(gè)多月。到目前為止,還沒有錯(cuò)誤操作的報(bào)

58、告。</p><p><b>　　6.結(jié)論</b></p><p>　　采用小且便宜的控制器并能防止欺詐的出租車計(jì)價(jià)器系統(tǒng)已被研發(fā)出來。該系統(tǒng)依賴于速度傳感器的脈沖加密操作，這種出租車計(jì)價(jià)器對(duì)故意偽造注入沿路電纜脈沖是高免疫的。優(yōu)越的完整性和安全性由系統(tǒng)的運(yùn)行周期內(nèi)隱蔽的重復(fù)傳輸模式得以保障?；诘脑瓌t,建立了一個(gè)用PIC16 F84的汽車可以加速到200公里/小時(shí)控