外文翻譯--低成本實時智能計價器傳感器

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

2、;/p><p>　　2012 年 3 月 8日</p><p>　　<文獻翻譯一：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>　　<文獻翻譯一：譯文></p><p

41、>　　低成本實時智能計價器傳感器</p><p><b>　　文摘</b></p><p>　　本文介紹了一個具有免疫欺詐的出租車計價器智能傳感器系統(tǒng)。該系統(tǒng)是基于嵌入式控制器在傳感器和出租車計價器之間使用了標準的RC5算法，用來執(zhí)行加密操作。特別強調了在保持最高系統(tǒng)完整性的前提下,促進復雜、尺寸和成本降到最低。初步的具體實現(xiàn)和驗證系統(tǒng)的安裝調試環(huán)境承諾在真實的

42、計程車其可行性應對欺詐處理的車費。</p><p><b>　　1.介紹</b></p><p>　　十多年來, 出租車計價器已被視為無所不在的設備,它可以讓全世界大城市的乘客避免被過度收費的麻煩。特別是如今所使用的儀表,都是基于單片機系統(tǒng)。處理計程車費,運動傳感器(如霍爾器件安裝變速箱和測速儀之間,每當車輛在運動產生電脈沖的微控制器為基礎出租車計價器費用計算。產生脈

43、沖流的周期是與車輛瞬時速度成反比的及實際比例常量取決于汽車類型。所以,傳感器一定時間間隔釋放出來的脈沖數(shù)影響所經(jīng)過的距離,而這距離是計價器用來計算車費的[1,2]。</p><p>　　事實上,目前的完整性出租車計價器長久以來就是個問題,由于這樣的事實,即采用的系統(tǒng)在使用中一個非常重要的漏洞,可能導致不可靠性和不當操作。缺點是系統(tǒng)會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

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

45、t;p><b>　　2.系統(tǒng)概述</b></p><p>　　這個系統(tǒng)的總體框圖已經(jīng)展示在圖1中。從本質上講,背后的理念發(fā)展成一個小控制器嵌入傳感器允許加密技術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,但明顯的準則是選擇一個,給硬件帶來的負擔最小,同時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期。隨后,兩組數(shù)據(jù)樣本使用兩個獨特的信息產生脈沖加密（在圖1中用鑰匙A和鑰匙B表示）。我們設計的系統(tǒng),A和B從一堆16獨特的鑰匙隨即選擇出,這樣便有了良好的安全,由此產生的對加密后的數(shù)據(jù)用這些關鍵號碼傳輸,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,其中一個將被送

47、到計價器進一步的費用計算。然而, 檢測兩種重建脈沖之間若有有任何差異,輸出到計價器會被保持在邏輯“0”終止了增加的費用用來說明車輛時固定未動的。最終,整個過程重復為傳輸控制器下一次的取樣脈沖。</p><p>　　3.詳細的操作和傳輸協(xié)議</p><p>　　大多數(shù)的出租車預裝的傳感器,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,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)。硬件復雜度和安全水平的平衡點是使用標準RC5的加密算法[3,4]。</p><p>　　圖2很詳細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加密和這一規(guī)定隙的數(shù)量在一個傳輸周期(和接收周期)以16顯示從槽0到槽15,從而每一個周期是4毫秒。</p><p>　　發(fā)射機起始于槽0空閑狀態(tài)時。在槽2和4儲藏的16位在前一個采樣周期被加密的傳感器的數(shù)據(jù)分別預先作為鑰匙A和鑰匙B,導致有兩套16位加密的數(shù)據(jù)。每個鑰匙都是64位長以及從所有的16把獨特的鑰匙偽隨機挑選出來。結果RC5被加密的數(shù)據(jù)和相關的鑰匙(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個采集的8位數(shù)據(jù)。圖3顯示了每個傳輸槽的數(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位的關鍵號碼,以終止位結束。數(shù)據(jù)傳輸速率是100 千位 /秒。促進二者之間的同步結束后,一個數(shù)據(jù)在槽6同時產生。在完成傳輸周期之前,同步數(shù)據(jù)就轉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,接著接收端傳送結束。下一個部分將詳細討論同步操作。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結束的傳輸框架的重復模式,從而有利于提高安全性。</p><p>　　在解密控制器數(shù)據(jù)同步被檢測到之后,其內部定時器每250微秒將能夠產生16個中斷輸出的脈沖計價器，解密后的數(shù)據(jù)脈沖流是在上個周期儲存在指定的16位緩沖區(qū)中。同樣在這個接收末端,每一個中斷的間隔被定義為“槽

52、”, 一個接收周期中共有16個槽，就像圖4中詳細的描述的。四個8位數(shù)據(jù)塊到達插槽3、5、9、11(符合那些傳輸結束的槽)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(映射的鑰匙編號和加密數(shù)據(jù)被做成獨一無二的預設的16鑰匙表)被解密。在槽15,產生的兩個解密后的16位二進制數(shù)據(jù)進行對比,只有當他們是相同的,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價器。然而,如果數(shù)據(jù)不匹配,邏輯“0”將會把整個緩沖區(qū)，凍結費

53、用。在槽15末,直到從發(fā)射機檢測到同步信號,中斷都會被禁用,然后整個接收周期重復。</p><p><b>　　4.同步</b></p><p>　　由于時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,達到這個目標可以在每一個操作周期發(fā)送一種允許的發(fā)射機數(shù)據(jù)模式來啟動接收機的接收操。在這個系統(tǒng)里，數(shù)據(jù)同步的模式是

54、10位長的，他的的槽架構與圖3中相似。每個完整的傳輸操作,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)在每一個操作周期產生的數(shù)據(jù)來實現(xiàn)的,使用單一預算法分配到兩側。值得注意的是,接收器開始其運行, 從發(fā)射機檢測到的同步信號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傳輸線纜和因此最終線路狀態(tài)輸入處于發(fā)射機,兩端的控制器,維持他們的空閑狀態(tài)4 毫秒(一個

55、完整的操作周期)。</p><p>　　5.實驗結果的系統(tǒng)原型</p><p>　　所描述的出租車智能傳感器已經(jīng)實現(xiàn)，且已在曼谷大都市地區(qū)測試利用該系統(tǒng)的實際操作。實時智能傳感器系統(tǒng)用微控制芯片公司一對小而且便宜的微控制器已經(jīng)被實現(xiàn), PIC16F84[7]。他們用8兆赫作為時鐘和一些外部組件對加密和解密的結束。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單地安裝的出租車計價器

56、右內保持最低化修改整個系統(tǒng)。</p><p>　　圖6(a)，實測波形顯示為系統(tǒng)一個完整的操作周期。需要注意的是,一個時間周期為4毫秒。沒有表明垂直痕跡,實際上是不可能的識別一個傳輸周期系統(tǒng)的開始和結束,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,測試隨機數(shù)據(jù)兩端彼此完全相同,如圖6(b)。從這個數(shù)字也注意到數(shù)據(jù)傳輸存在一個潛在的8個毫秒的延遲,但這不是問題因為票價計算依賴傳入超過一定時間

57、間隔的脈沖數(shù)。此外,脈沖重建的延遲,因而票價計算只是一小段時間,使其對旅客透明化。該系統(tǒng)還使用了500赫茲脈沖信號進行測試(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)。每當故意附加注入一些脈沖到電纜中，接收控制器將不產生脈沖,從而確定系統(tǒng)的功能。</p><p>　　為了在實際運作中詳盡的測試,原系統(tǒng)已經(jīng)安裝在曼谷當?shù)?0輛出租車在兩個多月。到目前為止,還沒有錯誤操作的報

58、告。</p><p><b>　　6.結論</b></p><p>　　采用小且便宜的控制器并能防止欺詐的出租車計價器系統(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，這種出租車計價器對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)的運行周期內隱蔽的重復傳輸模式得以保障。基于的原則,建立了一個用PIC16 F84的汽車可以加速到200公里/小時控