第一篇：外文翻譯終稿

探析招聘求職網(wǎng)站的發(fā)展 對人們的組織文化的看法產生的影響

1摘 要：公司企業(yè)在利用傳統(tǒng)招聘媒體時，通常是單靠他們的職位空缺，有限的向求職者提供信息。招聘網(wǎng)站的成立與發(fā)展，在另一方面，允許有意申請兩個或是多個職位的求職者提供有關公司企業(yè)的信息。然而，很少有人研究人們關于招聘網(wǎng)站存在的印象。本課題研究了招聘網(wǎng)站的各個方面，可能會導致求職者對組織文化的看法。結果表明，網(wǎng)站設計功能和組織的價值觀，政策，獎勵和目標的信息，組織文化影響觀眾的看法。

關鍵詞：網(wǎng)絡招聘,在線招聘;網(wǎng)絡招聘,招募品德的網(wǎng)站,組織文化。

1引言

越來越多的公司地將互聯(lián)網(wǎng)作為招聘員工的可行及有吸引力的工具。最近的一項調查研究表明證明了一點，互聯(lián)網(wǎng)招募是許多不同行業(yè)的人力資源專業(yè)人士的首選媒介。同樣，其他調查結果表明，來自公營和私營的公司招聘，人事部門使用互聯(lián)網(wǎng)比任何其他的人力資源管理活動更為頻繁。這與公司越來越多地依賴互聯(lián)網(wǎng)上的招聘成果有著明顯的影響，因為相比與傳統(tǒng)招聘媒體在其官方招聘網(wǎng)站提供更為具體詳明的信息，它使得這些行為更為可行。也是出于這個原因，招聘網(wǎng)站通常包括的信息有如下部分，例如員工推薦，利益的信息，公司的價值觀和報表等。潛在申請人提供有關公司的形象的方法之一是通過對組織文化看法的宣傳。組織文化的看法直接影響個人與組織的契合度，隨后影響潛在求職者的自主選擇公司職位。然而很少有研究存在于，怎樣的申請形式在招聘網(wǎng)站上展現(xiàn)關于組織文化的看法。這種探索性研究在于試圖確認招聘網(wǎng)站如何影響人們關于組織文化的看法。

2在線招聘：組織戰(zhàn)略和優(yōu)勢

Phillip W.Braddy、Adam W.Meade、Christina M.Kroustalis，Journal of Business and Psychology, Vol.20, No.4, Summer 2006 通過互聯(lián)網(wǎng)招募的組織主要有兩種渠道吸引求職者。首先，企業(yè)可以依靠第三方招聘網(wǎng)站發(fā)布招聘廣告（例如，HotJobs.com，Monster.com）。招聘啟事網(wǎng)站（也稱為“工作板”）向潛在的求職者提供一個信息交流中心，尋找適合他們的資歷和滿足他們的需求的職位。因此，工作板的能力是向有意在不同的公司中申請不同的職位的第三方平臺。雖然使用的第三方網(wǎng)站，可以大大提高招聘廣告閱讀瀏覽量和瀏覽人數(shù)，以及不同地理位置時間區(qū)域的不同群體在線尋找就業(yè)，但是信息的提供量一般是有限的。這樣的事實要歸功于，大多數(shù)第三方工作平臺會基于招聘廣告的內容列出相關的金額收費。雖然有時求職者會直接進入各自的雇用公司的網(wǎng)站提出職位的申請，在許多情況下，求職者必須通過第三方平臺與招聘單位間接接觸。第二種選擇是公司組織建立和維護自己的招聘官方網(wǎng)站，發(fā)布目前有關該公司的招聘廣告和其他的公司信息。這后一種是與最有可能也是有效的第三方平臺一起使用時的選擇。最近的一項調查表明，超過90％的美國大型公司企業(yè)組織保持著自己的官方招聘網(wǎng)站。這些專門招聘的網(wǎng)站，有幾個優(yōu)點。首先，公司企業(yè)組織的官方網(wǎng)頁上發(fā)布的信息內容成本是比工作板上便宜。信息內容可以是各不相同，官方網(wǎng)頁可以發(fā)布有關員工福利，公司的價值觀，公司的簡短歷史，和其他內容的信息，試圖創(chuàng)造一個積極的印象，保持一個良好的招聘形象。一個官方組織的招聘網(wǎng)站上的信息的總金額比招聘第三方平臺節(jié)省。同時一個主要好處是，職位申請人可以獲取更多信息，關于組織文化或是其他關于求職單位的方方面面，有助于更好地了解以及做出有關就業(yè)的決定。此外，這種類型的網(wǎng)絡招聘可以降低成本，盡量減少所需的時間，成功招募潛在人才，同時表現(xiàn)了創(chuàng)建招聘網(wǎng)站使用網(wǎng)絡招聘的公司是精通技術的。最后，網(wǎng)上的招聘求職者，讓他們直接在網(wǎng)上遞交申請材料相應的使成本降低?？傊?，我們相信，公司將繼續(xù)利用互聯(lián)網(wǎng)作為在未來的主要招聘媒介。我們也相信，該公司將繼續(xù)維持除了使用第三方平臺，并對其官方網(wǎng)站的依賴。

3信息理論和申請人的文化感知的形成

從經(jīng)濟學的研究上，信息理論是的買方和賣方擁有和信息的作用已經(jīng)被采納，解釋潛在申請人和招募組織之間的相互作用。從本質上講，這種理論認為，在有關組織的其他信息的情況下，一個潛在的申請人，將吸引周邊線索的進行推論。在招聘中，已發(fā)現(xiàn)信息理論的相當大的支持，如申請人已被證明有對招聘人 員的看法，依靠的是對租用場地的機構獲得的印象。例如，如果一個組織的招聘主管友好的態(tài)度，求職者人可以假設，這些都是素質以及整個公司的形象。這是經(jīng)常性發(fā)生的，因為求職者認為招聘人員代表各自的公司。這可能是因為申請人認為招聘人員作為代表其各自的組織。雖然這樣的招聘經(jīng)驗在許多情況下可以有信息的價值，當求職者擁有雇用組織的相關認知，這些經(jīng)驗的作用更為重要。我們相信，信息理論可以擴展到互聯(lián)網(wǎng)，用于解釋潛在申請人對組織文化的看法，再瀏覽招聘網(wǎng)站。例如，如果一個組織的網(wǎng)站，以及結構和有組織的，申請人可以推斷，組織價值觀。在沒有更多有意義的信息，信息理論認為網(wǎng)絡招聘網(wǎng)站應提供線索。

4討論

互聯(lián)網(wǎng)提供了一個平臺來傳輸大量的有關組織或是求職者的信息的，但已知目前很少有申請人利用這一信息平臺。目前的研究狀況是，試圖確定的招聘網(wǎng)站，可能會涉及到求職者的組織文化觀念方面，以解決這方面的不足。這些發(fā)現(xiàn)表明，網(wǎng)站的設計特點，組織政策，文化層面的具體引用的信息和其他一些項目都有一定的影響，但在目前的研究使用中，有關網(wǎng)站的內容，在確定什么文化觀念與財富榜500強企業(yè)的官方網(wǎng)站相關參與發(fā)揮了有益的作用。雖然參與者的反應各不相同，綜合總結后有三個共同的主題出現(xiàn)。首先，文化維度的具體提及是公司的網(wǎng)站上是典型的置頂部分，與會者表示與某個組織相關聯(lián)的某一方面的文化是非常受關注的。這一趨勢是真實的存在與所有文化層面。其次，使用網(wǎng)站的設計特點是要求高度創(chuàng)新，注重細節(jié)，明確團隊的發(fā)展方向，和多樣性的認識。最后，有關組織的政策，明確說明在于傳播公司特點以及多樣性。

5未來發(fā)展趨勢

本研究開始提出網(wǎng)站功能和內容，可能與形成求職者的組織文化印象，可以得出：更多的研究在這方面做出任何明確的結論之前是必要的。具體來說，我們希望未來的研究將確定招聘網(wǎng)站的存在與發(fā)展具有潛在的對人們關于組織文化的看法的影響。這些研究將允許不同的網(wǎng)站功能和內容因果結論的效力，產生建立各種文化觀念。此外，研究需要解決相關的其他問題，例如相對影響組織文化對求職者的工作追求意圖相比更為傳統(tǒng)的因素，像是工資和福利。最后，未來的研究調查方向通過不同的途徑研究，對于一個充滿希望又為招聘網(wǎng)站吸引的高素 質的求職者，相對于傳統(tǒng)的招聘信息來源的有效性。很明顯，在未來互聯(lián)網(wǎng)將是潛在求職者的一個重要的信息來源。然而，許多問題仍然存在于這一在招聘媒介中。

ORGANIZATIONAL RECRUITMENT WEBSITE EFFECTS ON VIEWERS' PERCEPTIONS OF ORGANIZATIONAL

CULTURE

Phillip W.Braddy Adam W.Meade Christina M.Kroustalis

North Carolina State University

ABSTRACT: When utilizing traditional recruitment media, organizations are typically limited to providing job seekers with information solely on their vacant positions.Organizational recruitment websites, on the other hand, allow organizations to provide prospective applicants with both job descriptions and other information about the organization.However, little research exists regarding the impressions that viewers gain from organizational recruitment websites.The present study identified aspects of recruitment websites that may give rise to job seekers' perceptions of organizational culture.Results indicated that both website design features and information about organizational values, policies, awards, and goals affected viewers' perceptions of organizational culture.KEY WORDS: Internet recruiting;online recruiting;web recruiting;recruit ment websites;organizational culture.INTRODUCTION Many organizations increasingly view the Internet as a viable and attractive tool for recruiting employees(Cober, Brown, Blumental, Doverspike, & Levy, 2000;Harrington, 2002).This is evidenced by recent survey research that indicates the Internet was the preferred medium of HR professionals when recruiting applicants for many positions in diverse industries(Chapman & Webster, 2003).Likewise, results of other surveys suggest that companies from both private and public sectors use the Internet more frequently for recruiting applicants than for any other HRM activity(e.g., Elliot & Tevavichulada, 1999).This increased reliance on the Internet has salient implications for organizations because it enables them to provide much more information on their official recruitment websites than is feasible with traditional recruitment media.Organizations provide this information in hopes that potential applicants favorably view the organization as a potential employer.For this reason, organizational recruitment websites commonly include features such as employee testimonials, benefits information, and organizational values statements.One way in which potential applicants draw conclusions about the organization is via perceptions of the culture of the organization.Perceptions of organizational culture directly affect perceptions of person-organization fit, which can subsequently affect how potential applicants self-select organizations(Judge & Cable, 1997).How ever, very little research exists regarding how applicants form culture perceptions from recruitment websites.Thus, this exploratory study at tempts to identify aspects of websites that influence viewer perceptions of organizational culture impressions.Online Recruiting: Organizational Strategies and Benefits Organizations recruiting via the Internet have two primary avenues to attract viewers into the applicant pool.First, organizations can rely upon third-parties that distribute job advertisements on a job listing website(e.g., HotJobs.com, Monster.com).Job listing websites(a.k.a., “job boards”)have the advantage of providing a clearinghouse for potential job applicants to search across organizations for positions appropriate to their qualifications and that meet their needs.Therefore, job boards have the ability to alert potential applicants to openings in many organizations.While the use of third-party websites or job boards can greatly increase the number of viewers reading the job advertisement and potentially reach a more geographically diverse group of applicants searching for jobs online(Crispin & Mehler, 1997), the amount of information that is available to the applicant is generally quite limited.This can likely be attributed to the fact that most third-party job boards charge fees based on the amount of content listed in the job advertisement.Moreover, although applicants are sometimes provided with direct access to the respective hiring companies' websites(Zusman & Landis, 2002), in many cases applicants must apply to the hiring organization indirectly through the third-party organization(Recruiting, 1999).A second option is for an organization to create and maintain its own official website to present job advertisements and additional information about the company(Zusman & Landis, 2002).This latter option is most likely to be effective when used in conjunction with job boards.One recent survey indicates that over 90% of large U.S.organizations maintain their own official recruiting websites(Cappelli, 2001).These websites, dedicated solely to recruitment, have several advantages.First, content can be posted much more cheaply on the organization's official web page than on a job board.Though content varies consider ably, organizations can post information about employee benefits, organizational values, a brief history of the organization, and additional content to attempt to create a positive impression needed to maintain a favorable recruitment image(Gatewood, Gowan, & Lautenschlager, 1993).The overall amount of information on an official organizational recruitment website is much greater than from a job advertisement alone(Braddy, Thompson, Wuensch, & Grossnickle, 2003).A major benefit of this additional content is that applicants can acquire more information regarding organizational culture, which may facilitate making better informed employment-related decisions.Additionally, this type of web recruiting can reduce costs(Cober et al., 2000;Kay, 2000;Marcus, 2001), minimize the amount of time required to successfully recruit applicants(Web Recruiting Advantages, 2001), and create the perception that companies who use online recruiting are technologically savvy(Fister, 1999).Finally, online recruiting reduces application costs for job seekers by allowing them to directly submit application materials online(Cappelli, 2001;Zusman & Landis, 2002).In short, we believe that companies will continue to utilize the Internet as a primary recruitment medium in the future.We also believe that organizations will continue to maintain and rely upon their official websites in addition to using third party job boards.Signaling Theory and the Formation of Applicant Culture Perceptions Signaling theory was developed from economics research on the role of information possessed by buyer and seller(Spence, 1974)and has been adopted to explain the interaction between potential applicants and recruiting organizations(Rynes, Bretz, & Gerhart, 1991;Rynes & Miller, 1983;Spence, 1973).In essence, this theory suggests that in the absence of other information about an organization, a potential applicant will draw inferences about the organization based on peripheral cues.In the recruitment context, considerable support for signaling theory has been found as applicants have been shown to rely on perceptions of recruiters to derive their impressions of hiring organizations(Goltz & Giannantonio, 1995;Rynes et al., 1991;Rynes & Miller, 1983;Turban, 2001;Turban, Forret, & Hendrickson, 1998).For example, if an organization's recruiter was perceived as both competent and friendly, applicants may assume that these are defining qualities of the entire organization as well.This likely occurs because applicants view recruiters as being representative of their respective organizations(Rynes & Miller, 1983).Though such recruiting experiences can have signaling value under many circumstances, the role of such experiences is much more significant when applicants possess little knowledge about the hiring organization(Rynes et al., 1991).We believe signaling theory can be extended to the Internet domain to explain how potential applicants form organizational culture perceptions after viewing recruitment websites.For instance, if an organization's website is well structured and organized, applicants may infer that the organization values and possesses such characteristics.In the absence of more meaningful information(e.g., direct knowledge from an incumbent, a site visit, etc.), signaling theory suggests that an Internet recruiting website should provide cues to the viewer about the nature of the organization.DISCUSSION The Internet provides organizations with a tool to transmit large amounts of information about the organization to job seekers, yet very little is currently known about the manner in which applicants utilize this information.The current study sought to address this deficiency by identifying aspects of recruitment websites that may be related to job seekers' organizational culture perceptions.These findings indicate that website design features(e.g., employee testimonials illustrating team work), information about organizational policies(e.g., continuing education programs), specific references to culture dimensions(e.g., “the organization values workers who are creative and innovative”), and other miscellaneous but relevant website content(e.g., listing of organizational awards won)played an instrumental role in determining what culture perceptions participants associated with the Fortune 500 companies whose websites were used in the current study.Though the percentage of participant responses assigned to the aforementioned categories varied considerably across the nine culture dimensions, there were three common themes that emerged.First, the specific references made about culture dimensions(i.e., content)on a company's website was typically one of the top most cited reasons that participants indicated for associating a particular aspect of culture with a given organization.This trend was true for all culture dimensions, excluding emphasis on rewards.Second, the use of website design features was indicated as being highly important for conveying perceptions of innovation, attention to detail, team orientation, and diversity.Finally, clearly stating relevant organizational policies seemed instrumental for transmitting companies' emphases on rewards, supportiveness, and diversity.FUTURE RESEARCH The present study begins to outline website features and content that may be related to the formation of job seekers' organizational culture impressions, but much additional research in this area is needed before any definitive conclusions can be drawn.Specifically, we hope that future researchers will manipulate portions of websites identified in this study as having a potential impact on viewers' perceptions in both con trolled laboratory and field environments.Such studies would permit causal conclusions to be drawn regarding the efficacy of different website features and content for creating various culture perceptions.In addition, research is needed to address the relative effects of organizational culture impressions on applicants' job-pursuit intentions when compared to more traditional factors, such as pay and benefits.Finally, another promising yet slightly different avenue for future research is to investigate the effectiveness of organizational recruitment websites in attracting top quality applicants relative to traditional recruitment sources(e.g., such as recruiters and newspaper advertisements).It is clear that the Internet will be a significant source of information for potential job applicants in the future.However, many questions remain regarding the precise role of this medium in the recruitment process.

第二篇：外文翻譯

當今時代是一個自動化時代，交通燈控制等很多行業(yè)的設備都與計算機密切相關。因此，一個好的交通燈控制系統(tǒng)，將給道路擁擠，違章控制等方面給予技術革新。隨著大規(guī)模集成電路及計算機技術的迅速發(fā)展，以及人工智能在控制技術方面的廣泛運用，智能設備有了很大的發(fā)展，是現(xiàn)代科技發(fā)展的主流方向。本文介紹了一個智能交通的系統(tǒng)的設計。該智能交通燈控制系統(tǒng)可以實現(xiàn)的功能有：對某市區(qū)的四個主要交通路口進行控制：個路口有固定的工作周期，并且在道路擁擠時中控制中心能改變其周期：對路口違章的機動車能夠即時拍照，并提取車牌號。在世界范圍內，一個以微電子技術，計算機和通信技術為先導的，一信息技術和信息產業(yè)為中心的信息革命方興未艾。而計算機技術怎樣 與實際應用更有效的結合并有效的發(fā)揮其作用是科學界最熱門的話題，也是當今計算機應用中空前活躍的領域。本文主要從單片機的應用上來實現(xiàn)十字路口交通燈智能化的管理，用以控制過往車輛的正常運作。

研究交通的目的是為了優(yōu)化運輸，人流以及貨流。由于道路使用者的不斷增加，現(xiàn)有資源和基礎設施有限，智能交通控制將成為一個非常重要的課題。但是，智能交通控制的應用還存在局限性。例如避免交通擁堵被認為是對環(huán)境和經(jīng)濟都有利的，但改善交通流也可能導致需求增加。交通仿真有幾個不同的模型。在研究中，我們著重于微觀模型，該模型能模仿單獨車輛的行為，從而模仿動態(tài)的車輛組。

由于低效率的交通控制，汽車在城市交通中都經(jīng)歷過長時間的行進。采用先進的傳感器和智能優(yōu)化算法來優(yōu)化交通燈控制系統(tǒng)，將會是非常有益的。優(yōu)化交通燈開關，增加道路容量和流量，可以防止交通堵塞，交通信號燈控制是一個復雜的優(yōu)化問題和幾種智能算法的融合，如模糊邏輯，進化算法，和聚類算法已經(jīng)在使用，試圖解決這一問題，本文提出一種基于多代理聚類算法控制交通信號燈。

在我們的方法中，聚類算法與道路使用者的價值函數(shù)是用來確定每個交通燈的最優(yōu)決策的，這項決定是基于所有道路使用者站在交通路口累積投票，通過估計每輛車的好處(或收益)來確定綠燈時間增益值與總時間是有差異的，它希望在它往返的時候等待，如果燈是紅色，或者燈是綠色。等待，直到車輛到達目的地，通過有聚類算法的基礎設施，最后經(jīng)過監(jiān)測車的監(jiān)測。

我們對自己的聚類算法模型和其它使用綠燈模擬器的系統(tǒng)做了比較。綠燈模擬器是一個交通模擬器，監(jiān)控交通流量統(tǒng)計，如平均等待時間，并測試不同的交通燈控制器。結果表明，在擁擠的交通條件下，聚類控制器性能優(yōu)于其它所有測試的非自適應控制器，我們也測試理論上的平均等待時間，用以選擇車輛通過市區(qū)的道路，并表明，道路使用者采用合作學習的方法可避免交通瓶頸。

本文安排如下：第2部分敘述如何建立交通模型，預測交通情況和控制交通。第3部分是就相關問題得出結論。第4部分說明了現(xiàn)在正在進一步研究的事實，并介紹了我們的新思想。

The times is a automation times nowadays,traffic light waits for much the industey equipment to go hand in hand with the computer under the control of.Therefore,a good traffic light controls system,will give road aspect such as being crowded,controlling against rules to give a technical improvement.With the fact that the large-scale integrated circuit and the computer art promptness develop,as well as artificial intelligence broad in the field of control technique applies,intelligence equipment has had very big development,the main current being that modern science and technology develops direction.The main body of a book is designed having introduccd a intelligence traffic light systematically.The function being intelligence traffic light navar’s turn to be able to come true has：The crossing carries out supervisory control on four main traffic of some downtown area;Every crossing has the fixed duty period,charges centrefor being able to change it’s period and in depending on a road when being crowded;The motro vehicle breaking rules and regulations to the crossing is able to take a photo immediately,abstracts and the vehicle shop sign.Within world range ,one uses the microelectronics technology,the computer and the technology communicating by letter are a guide’s,centering on IT and IT industry information revolution is in the ascendant.But,how,computer art applies more effective union and there is an effect’s brought it’s effect into play with reality is the most popular topic of scientific community,is also that computer applications is hit by the unparalleled active field nowadays.The main body of a book is applied up mainly from slicing machine’s only realizing intellectualized administration of crossroads traffic light,use operation in controlling the vehicular traffic regularity.Transportation research has the goal to optimize transportation flow of people and goods.As the number of road users constantly increases, and resources provided by current infras-tructures are limited, intelligent control of traffic will become a very important issue in thefuture.However, some limitations to the usage of intelligent tra?c control exist.Avoidingtraffic jams for example is thought to be beneficial to both environment and economy, butimproved traffic-flow may also lead to an increase in demand [Levinson, 2003].There are several models for traffic simulation.In our research we focus on microscopicmodels that model the behavior of individual vehicles, and thereby can simulate dynam-ics of groups of vehicles.Research has shown that such models yield realistic behavior[Nagel and Schreckenberg, 1992, Wahle and Schreckenberg, 2001].Cars in urban traffic can experience long travel times due to inefficient traffic light con-trol.Optimal control of traffic lights using sophisticated sensors and intelligent optimizationalgorithms might therefore bevery beneficial.Optimization of traffic light switching increasesroad capacity and traffic flow, and can prevent tra?c congestions.Traffic light control is acomplex optimization problem and several intelligent algorithms, such as fuzzy logic, evo-lutionary algorithms, and reinforcement learning(RL)have already been used in attemptsto solve it.In this paper we describe a model-based, multi-agent reinforcement learningalgorithm for controlling traffic lights.In our approach, reinforcement learning [Sutton and Barto, 1998, Kaelbling et al., 1996]with road-user-based value functions [Wiering, 2000] is used to determine optimal decisionsfor each traffic light.The decision is based on a cumulative vote of all road users standingfor a traffic junction, where each car votes using its estimated advantage(or gain)of settingits light to green.The gain-value is the difference between the total time it expects to waitduring the rest of its trip if the light for which it is currently standing is red, and if it is green.The waiting time until cars arrive at their destination is estimated by monitoring cars flowingthrough the infrastructure and using reinforcement learning(RL)algorithms.We compare the performance of our model-based RL method to that of other controllersusing the Green Light District simulator(GLD).GLD is a traffic simulator that allows usto design arbitrary infrastructures and traffic patterns, monitor traffic flow statistics such asaverage waiting times, and test different traffic light controllers.The experimental resultsshow that in crowded traffic, the RL controllers outperform all other tested non-adaptivecontrollers.We also test the use of the learned average waiting times for choosing routes of cars through the city(co-learning), and show that by using co-learning road users can avoidbottlenecks.

第三篇：外文翻譯

設計一個位于十字路口的智能交通燈控制系統(tǒng)

摘要：本文模型使用模糊本體的交通燈控制域，并把它應用到控制孤立十字路口。本文最重要的目的之一是提出一個獨立的可重復使用的交通燈控制模塊。通過這種方式，增加軟件的獨立性和為其他的軟件開發(fā)活動如測試和維護，提供了便利。專家對本體論進行手動的開發(fā)和評估。此外，交通數(shù)據(jù)提取和分類路口使用的人工神經(jīng)網(wǎng)絡的圖像處理算法。根據(jù)預定義的XML架構，這種信息轉化為XML實例映射到適合使用模糊推理引擎的模糊規(guī)則的模糊本體。把本系統(tǒng)的性能與其他類似的系統(tǒng)性能進行比較。比較結果顯示：在所有的交通條件下，在每個周期中，對每輛車它有低得多的平均延遲時間與其他的控制系統(tǒng)相比。

關鍵詞:模糊本體,智能代理,智能交通系統(tǒng)(ITS),交通信號燈控制(TLC),孤立的十字路口,圖像處理,人工神經(jīng)網(wǎng)絡

1.引言

作為城市交通增加的結果,道路網(wǎng)絡的能力有限和發(fā)展交通工具和方法的技術方面，許多實體，關系，情況和規(guī)則已經(jīng)進入交通燈控制域和轉化成為一個知識領域。這個領域的建模知識幫助交通代理和應用有效地管理關于實時條件下的交通。全面知識建模領域的一個最合適的方法是使用本體概念?！氨倔w論是一個正式的、明確的一個共享的概念化的規(guī)范。以前的模型是基本的本體建設的基礎，為下列建立一個共享的語義豐富的知識域。除了本體作為概念化的形式主義的重要性，它有可能超過所代表的數(shù)據(jù)。這種能力將提高有關性能的決定和其他非智能系統(tǒng)的功能特點。在近年來，本體論上的研究正成為一個新的熱點話題在不同的活動，如人工智能，知識管理，語義網(wǎng)絡，電子商務和幾個其他應用領域。這些領域之一是智能交通系統(tǒng)。一些努力已制成這個通過展示和使用本體檢測交通領域擁塞，管理非城市道路氣象事件，駕駛阿德?！骼锵到y(tǒng)，共享和整合一個智能交通系統(tǒng)。本文的目的是介紹一個紅綠燈有效控制孤立交叉口這方面的知識重用的控制本體。這種新的辦法適用于智能代理使用知識決策模糊。該系統(tǒng)采用的圖像來自安裝了監(jiān)控攝像機拍攝的路口。這些圖像處理利用圖像處理算法和神經(jīng)網(wǎng)絡的方法，然后發(fā)送到一個智能代理。第2節(jié)中，我們將簡要地解釋了在這項工作中運用的技術包括seman-TIC網(wǎng)絡技術，智能代理技術和交通的回地面光控制方法。在第3節(jié)，新的系統(tǒng)架構是基于分層語義網(wǎng)絡架構。第4節(jié)介紹交通燈控制的模糊本體的建設。第五節(jié)從路口提取的圖像信息解釋。在第6節(jié)，智能系統(tǒng)的運作被完整描述，最后在第7節(jié)對所提出的方法進行評估，對結論進行闡述。

2.背景

本節(jié)說明在這項工作中的應用技術包括語義網(wǎng)絡技術，特別本體和模糊本體。此外，國家的交通燈控制的藝術方法是簡要介紹。2.1.語義網(wǎng)絡技術

語義網(wǎng)絡被定義為當前Wed的延伸，這些網(wǎng)站的信息都給出明確的含義;使電腦與人更好的合作。有幾層語義Web的建議源自伯納斯滯后階段。在此類別中的所有規(guī)則如表1所示。圖.4顯示輸出模式的示意圖。本次評選有助于智能系統(tǒng)，以確定下一步的階段測序。

另一種模糊的規(guī)則類別涉及估計優(yōu)化周期時間。這些規(guī)則的模糊變量是天氣條件，時間，每天平均車輛擁堵情況。出于這個原因，60個模糊規(guī)則被定義了。從氣象研究所取得氣象條件。日期和時間也是在交通專家的知識的基礎上以模糊變量形式預先定義的。圖5顯示日期，時間和周期時間的隸屬函數(shù)。當天的參數(shù)是在日歷基礎上基于假期和正常的一天與周期時間量的關系預定義的。例如，假期期間的周期時間是較平日少。因此，平日的隸屬度比假期多。

例如一個階段選型的模糊規(guī)則如下所述：“如果一個路口的類型是四的方式，平均車輛擁堵低，平均行人擁堵是中等，然后相類型是簡單的兩階段”。此外，為周期時間估計的模糊規(guī)則表示如下：“如果天氣條件是晴天，時間是早晨，天是正常的，平均車輛擁堵是低，則周期時間短”。在此類別中的所有規(guī)則都列在附錄A。

在此步驟結束時，應該對交通燈邏輯控制的項目的有效性進行評估。此功能是使用專家的意見。評價過程的主要目的是顯示發(fā)展的本體和其相關的軟件環(huán)境的用處。雖然所有的信息，尤其是交通燈控制規(guī)則已提取國際標準和科學交通文學，專家的知識優(yōu)勢是他們最后的正確性驗證標準。所有模糊規(guī)則，包括優(yōu)化周期時間和相位類型的規(guī)則，在這個過程中，準備以調查問卷形式和展現(xiàn)給一些專家包括從德黑蘭警察局交通上校和兩名來自德黑蘭的交通組織工程師。由于德爾菲專家的意見，約有84％的淘汰型規(guī)則和優(yōu)化周期時間的87％被接受。此外，所有交通邏輯控制的元素包括概念，關系，屬性和公理都被這些專家進行了評估和驗證。我們評估邏輯交通控制是基于理論知識的。在這個過程中進行了兩項活動，包括檢查的要求和能力的問題，并在目標應用環(huán)境測試本體。由于邏輯交通控制已建成的基礎上，如指定要求優(yōu)化循環(huán)時間，逐步淘汰型，交通的移動和優(yōu)化綠燈時間，每個階段的序列中，第一項活動是最好的結果。邏輯交通控制滿足所有的交通燈控制的需求，并能回答的能力問題?？冃гu估機制，可以支持這種說法。在部分實驗結果我們驗證了這一過程。

第四篇：外文翻譯

中原工學院畢業(yè)設計（論文）譯文

超聲測距系統(tǒng)設計

原文出處：傳感器文摘 布拉福德：1993年第13頁

摘要：超聲測距系統(tǒng)技校在工業(yè)場車輛導航水聲工程等領域都具有了廣泛的應用價值，目前已應用于物理測量，機器人自動導航以及空氣中與水下的目標探測、識別定位等場合，因此，深入研究超聲的探測理論和方法具有重要的實踐意義，為了進一步提高測量的精確度，滿足工程人員對測量精度測距量程和測距儀使用的要求，本文研制了一套基于單片機的使拱式超聲測距系統(tǒng)。關鍵詞：超聲波 測距儀 單片機

1、前言

隨著科技的發(fā)展，人們生活水平的提高，城市發(fā)展建設加快，城市給排水系統(tǒng)也有較大發(fā)展，其狀況不斷改善，但是，由于歷史原因合成時間性的許多不可預見因素，城市給排水系統(tǒng)，特別是排水系統(tǒng)往往落后于城市建設，因此，經(jīng)常出現(xiàn)開挖已經(jīng)建設好的建筑設施來改造排水系統(tǒng)的現(xiàn)象。城市污水給人們帶來的困擾，因此箱的排污疏通對大城市給排水系統(tǒng)污水理，人們生活舒適顯得非常重要。而設計研制箱涵排水疏通移動機器人的自動控制系統(tǒng)，保證機器人在箱涵中自由排污疏通，是箱涵排水系統(tǒng)疏通機器人的設計研制的核心部分，控制系統(tǒng)核心部分就是超聲波測儀的研制。因此，設計好的超聲波測距儀就顯得非常重要了。

1.1課題背景

隨著經(jīng)濟的發(fā)展與汽車科學技術的進步，公路交通呈現(xiàn)出行駛高速化、車流密集化和駕駛員非職業(yè)化的趨勢。同時，隨著汽車工業(yè)的飛速發(fā)展，汽車的產量和保有量都在急劇增加。但公路發(fā)展、交通管理卻相對落后，導致了交通事故與日劇增，城市里尤其突出。智能交通系統(tǒng)ITS是目前世界上交通運輸科學技術的前沿技術，它在充分發(fā)揮現(xiàn)有基礎設施的潛力，提高運輸效率，保障交通安全，緩解交通賭塞，改善城市環(huán)境等方面的卓越效能，已得到各國政府的廣泛關注。中國政府也高度重視智能交通系統(tǒng)的研究開發(fā)與推廣應用。汽車防撞系統(tǒng)作為ITS 發(fā)展的一個基礎，它的成功與否對整個系統(tǒng)有著很大的作用。從傳統(tǒng)上說，汽車的安全可以分為兩個主要研究方向:一是主動式安全技術，即防止事故的發(fā)生，該種方式是目前汽車安全研究的最終目的;二是被動式安全技術，即事故發(fā)生后的乘員保護。目前汽車安全領域被動安全研究較多，主要從安全氣囊、ABS(防抱死系統(tǒng))和懸架等方面著手，以保證駕乘人員的安全。從經(jīng)濟性和安全性兩方面來說，中原工學院畢業(yè)設計（論文）譯文

這些被動安全措施是在事故發(fā)生時刻對車輛和人員進行保護，有很大的局限性，因而車輛的主動安全研究尤為重要，引出了本文研究的基于單片機的超聲波測距系統(tǒng)。這個系統(tǒng)是一種可向司機預先發(fā)出視聽語音信號的探測裝置。它安裝在汽車上，能探測企圖接近車身的行人、車輛或周圍障礙物;能向司機及乘員提前發(fā)出即將發(fā)生撞車危險的信號，促使司機采取應急措施來應付特殊險情，避免損失。

1.2 課題設計的意義

隨著現(xiàn)代社會工業(yè)化程的發(fā)展，汽車這一交通工具正為越來越多的人所用，但是隨之而來的問題也顯而易見，那就是隨著車輛的增多，交通事故的頻繁發(fā)生，由此導致的人員傷亡和財產損失數(shù)目驚人。對于公路交通事故的分析表明，80%以上的車禍事由于駕駛員反應不及所引起的，超過65%的車輛相撞屬于追尾相撞，其余則屬于側面相撞。奔馳汽車公司對各類交通事故的研究表明：若駕駛員能夠提早1S 意識到有事故危險并采取相應的正確措施，則絕大多數(shù)的交通事故都可以避免。因此，大力研究開發(fā)如汽車防撞裝置等主動式汽車輔助安全裝置，減少駕駛員的負擔和判斷錯誤，對于提高交通安全將起到重要的作用。顯然，此類產品的研究開發(fā)具有極大的實現(xiàn)意義和廣闊的應用前景。

1.3超聲波測距在汽車上應用的介紹

超聲波倒車測距儀(俗稱電子眼)是汽車倒車防撞安全輔助裝置，能以聲音或者更為直觀的數(shù)字形式動態(tài)顯示周圍障礙物的情況。其較早的產品是用蜂鳴器報警，蜂鳴聲越急，表示車輛離障礙物越近。后繼的產品可以顯示車后障礙物離車體的距離。其大多數(shù)產品探測范圍在0.4～1.5m，有的產品能達到0.35～2.5m，并有距離顯示、聲響報警、區(qū)域警示和方位指示，有些產品還具備開機自檢功能。目前市場上還出現(xiàn)了具有語音報警功能的產品。這些產品存在的主要問題是測量盲區(qū)大，報警滯后，未考慮汽車制動時的慣性因素，使駕駛者制動滯后，抗干擾能力不強，誤報也較多。汽車防撞雷達之所以能實現(xiàn)防撞報警功能，主要有超聲波這把無形尺子, 它測量最近障礙物的距離, 并告訴給車主。其實超聲測距原理簡單: 它發(fā)射超聲波并接收反射回波, 通過單片機計數(shù)器獲得兩者時間差t, 利用公式S=Ct/2計算距離, 其中S為汽車與障礙物之間的距離, C為聲波在介質中的傳播速度。

本文介紹的超聲測距系統(tǒng)共有2只超聲波換能器(俗稱探頭),分別布置在汽車的后左、后右2個位置上。能檢測前進和倒車方向障礙物距離, 通過后視鏡內置的

中原工學院畢業(yè)設計（論文）譯文

顯示單元顯示距離和方位, 發(fā)出一定的聲響, 起到提示和警戒的作用。系統(tǒng)采用一片STC89C52單片機對兩路超聲波信號進行循環(huán)采集。超聲波是指頻率高于20HHZ的機械波。為了以超聲波作為檢測手段，必須產生超生波和接收超聲波。完成這種功能的裝置就是超聲波傳感器，習慣上稱為超聲波換能器或超聲波探頭。超聲波傳感器有發(fā)送器和接收器，但一個超聲波傳感器也可具有發(fā)送和接收聲波的雙重作用。超聲波傳感器是利用壓電效應的原理將電能和超聲波相互轉化，即在發(fā)射超聲波的時候，將電能轉換，發(fā)射超聲波；而在收到回波的時候，則將超聲振動轉換成電信號。超聲波測距的原理一般采用渡越時間法。首先測出超聲波從發(fā)射到遇到障礙物返回所經(jīng)歷的時間，再乘以超聲波的速度就得到二倍的聲源與障礙物之間的距離。測量距離的方法有很多種，短距離的可以用尺，遠距離的有激光測距等，超聲波測距適用于高精度的中長距離測量。因為超聲波在標準空氣中的傳播速度為331.45米/秒，由單片機負責計時，單片機使用12.0M晶振，所以此系統(tǒng)的測量精度理論上可以達到毫米級。由于超聲波指向性強，能量消耗緩慢，在介質中傳播距離遠，因而超聲波可以用于距離的測量。利用超聲波檢測距離，設計比較方便，計算處理也較簡單，并且在測量精度方面也能達到要求。超聲波發(fā)生器可以分為兩類：一類是用電氣方式產生超聲波，一類是用機械方式產生超聲波。本設計屬于近距離測量，可以采用常用的壓電式超聲波換能器來實現(xiàn)觸發(fā)單元。

利用超聲波測距的工作，就可以根據(jù)測量發(fā)射波與反射波之間的時間間隔，從而達到測量距離的作用。其主要有三種測距方法：

（1）相位檢測法，相位檢測法雖然精度高，但檢測范圍有限；

（2）聲波幅值檢測法，聲波幅值檢測法易受反射波的影響；

（3）渡越時間檢測法，渡越時間檢測法的工作方式簡單，直觀，在硬件控制和軟件設計上都非常容易實現(xiàn)。其原理為：檢測從發(fā)射傳感器發(fā)射超聲波，經(jīng)氣體介質傳播到接收傳感器的時間，這個時間就是渡越時間。本設計的超聲波測距就是使用了渡越時間檢測法。在移動車輛中應用的超聲波傳感器，是利用超聲波在空氣中的定向傳播和固體反射特性（縱波），通過接收自身發(fā)射的超聲波反射信號，根據(jù)超聲波發(fā)出及回波接收的時間差和傳播速度，計算傳播距離，從而得到障礙物到車輛的距離。

中原工學院畢業(yè)設計（論文）譯文 超聲波測距原理

2.1 壓電式超聲波發(fā)生器原理

壓電式超聲波發(fā)生器實際上是利用壓電晶體的諧振來工作的。超聲波發(fā)生器內部結構，它有兩個壓電晶片和一個共振板。當它的兩極外加脈沖信號，其頻率等于壓電晶片的固有振蕩頻率時，壓電晶片將會發(fā)生共振，并帶動共振板振動，便產生超聲波。反之，如果兩極板間未加電壓，當共振板接收到超聲波時，將壓迫壓電晶片做振動，將機械能轉換為電信號，這是它就成為超聲波接收器了。

測量脈沖到達時間的傳統(tǒng)方法是以擁有固定參數(shù)的接收信號開端為基礎的。這個信號恰恰選于噪音水平之上，然而脈沖到達時間被定義為脈沖信號剛好超過界限的第一時刻。一個物體的脈沖強度很大程度上取決于這個物體的自然屬性尺寸還有它與傳感器的距離。進一步說，從脈沖起始點到剛好超過界限之間的時間段隨著脈沖的強度而改變。結果，一種錯誤便出現(xiàn)了——兩個擁有不同強度的脈沖在不同時間超過界限卻在同一時刻到達。強度較強的脈沖會比強度較弱的脈沖超過界限的時間早點，因此我們會認為強度較強的脈沖屬于較近的物體。

2.2 超聲波測距原理

超聲波發(fā)射器向某一方向發(fā)射超聲波，在發(fā)射時刻的同時開始計時，超聲波在空氣中傳播，途中碰到障礙物就立即返回來，超聲波接收器收到反射波就立即停止計時。超聲波在空氣中的傳播速度為340m/s，根據(jù)計時器記錄的時間t，就可以計算出發(fā)射點距離障礙物的距離(s)，即：s=340t/2

中原工學院畢業(yè)設計（論文）譯文

3、超聲波測距系統(tǒng)的電路設計

系統(tǒng)的特點是利用單片機控制超聲波的發(fā)射和超聲波自發(fā)射至接受往返時間的計時，單片機選用C51，經(jīng)濟易用，且片內有4K的ROM，便于編程。電路的原理如圖1所示。

圖1 電路原理圖

中原工學院畢業(yè)設計（論文）譯文

3.1 40kHz脈沖的產生與超聲波發(fā)射

測距系統(tǒng)中的超聲波傳感器采用UCM40的壓電陶瓷，它的工作電壓是40kHz的脈沖信號，這由單片機執(zhí)行下面的程序來產生。puzel：mov 14h，#12h

here： cp1.0；

nop；

nop；

nop；

djnz 14h，here；

Ret

前方測距電路的輸出端接單片機P1.0端口，單片機執(zhí)行上面的程序后，在P1.0端口輸出一個40khz的脈沖信號，經(jīng)過三極管T放大，驅動超聲波發(fā)射頭UCM40T，發(fā)出40khz的脈沖超聲波，且持續(xù)發(fā)射200ms。右側合作側測距電路的輸入端分別接P1.1和P1.2端口，工作原理和前方測距電路相同。

超聲波發(fā)射持續(xù)200ms 輸出40kHz方波

3.2 超聲波的接收與處理

接收頭采用與發(fā)射頭配對的UCM40R，將超聲波調制脈沖變?yōu)殡妷盒盘枺?jīng)運算放大器ic1a和ic1b兩級放大后加至IC2,。IC2是帶有鎖定環(huán)的音頻譯碼集成塊LM567，內部壓控振蕩器的中心頻率f0=1/1.1R8C3，電容C4決定其帶寬。調節(jié)R8在發(fā)射的載頻上，則LM567輸入信號大于25mv，輸出端8腳由5由高電平躍變?yōu)榈碗娖?，作為中斷請求信號，送至單片機處理。

前方測距電路的輸出端接至單片機INT0端口，中斷優(yōu)先級最高，左、右測距電路的輸出通過與門IC3A的輸出接單片機的INT1端口，同時單片機P1.3和P1.4接到IC3A的輸入端，中斷源的識別由程序查詢來處理，中斷優(yōu)先級為先右后左。部分源程序如下： receive1：push psw

push acc

clr ex1；關中斷源1

jnb p1.1，right;P1.1引腳為0，轉至右側距電路中斷服務程序

jnb p1.2,left;P1.2 引腳為0，轉至左測距中斷電路服務程序 returne：SETB EX1；

開外部中斷1

pop acc

中原工學院畢業(yè)設計（論文）譯文

pop psw

reti right：

...；

右測距電路中斷服務程序入口

ajmp return

left：

...；

左測距電路中斷服務程序入口

ajmp return

3.3 計算超聲波傳播時間

在啟動發(fā)射電路的同時啟動單片機內部的定時器T0，利用定時器的計數(shù)功能，記錄超聲波發(fā)射的時間和受到反射波的時間。當收到超聲波反射波時，接受電路輸出端產生一個負跳變，在INT0或INT1端產生一個中斷請求信號，單片機響應外部中斷請求，執(zhí)行外部中斷服務子程序，讀取時間差，計算距離。其部分源程序如下：

RECEIVEO: PUSH PSW

PUSH ACC CLR EX0;

關外部中斷0 讀取時間值

MOV R7,TH0;MOV R6,TL0 CLR C MOV A,R6 SUBB A,#0BBH;MOV 31H,A;MOV A,R7 SUBB A,#3CH MOV 30H,A SETB EX0;POP ACC

POP PSW

RETI 對于一個平坦的目標，測量距離包括兩個階段：粗糙的測量和精細的測量。第一步：脈沖的傳送產生一種簡單的超聲波

第二步：根據(jù)公式改變回波放大器的獲得量直到回撥被檢測到。第三步：檢測兩種回波的振幅與過零時間。

計算時間值 存儲結果

開外部中斷0

中原工學院畢業(yè)設計（論文）譯文

第四步：設置回波放大器的所得規(guī)格輸出，假定是3v。通過脈沖的周期設置下一個脈沖。根據(jù)第二部的數(shù)據(jù)設定時間窗。

第五步：發(fā)射兩竄脈沖產生干擾波。測量過零時間與回波振幅。如果逆向發(fā)生在回波中，決定要不通過在低氣壓插入振幅。

第六步：通過公式計算距離y。

中原工學院畢業(yè)設計（論文）譯文

4、超聲波測距系統(tǒng)的軟件設計

軟件分為倆部分，主程序和中斷服務程序。主程序完成初始化工作、各路超聲波發(fā)射和接收順序的控制。定時中斷服務子程序完成三方向超聲波的輪流發(fā)射，外部中斷服務子程序主要完成時間值的讀取、距離計算、結果的輸出等工作。

中原工學院畢業(yè)設計（論文）譯文

5、結論

對所要求測量范圍30cm-200cm內的平面物體做了多次測量發(fā)現(xiàn)，其最大誤差為1.5cm，且重復性好?？梢娀趩纹瑱C設計的超聲波測距系統(tǒng)具有硬件結構簡單、工作可靠、測量誤差小等特點。因此，它不僅可用于移動機器人，還可以用在其他檢測系統(tǒng)中。

思考：至于為什么不用接收管做放大電路，因為放大倍數(shù)搞不好，集成放大電路，還帶自動電平增益控制，放大倍數(shù)為76db，中心頻率是38k到40k，剛好是超聲波傳感器的諧振頻率。

中原工學院畢業(yè)設計（論文）譯文

參考文獻

1.Fox，J.D.，Khuri-Yakub，B.T.and Kino，G.S.，“High Frequency Acoustic Wave Measurement in Air”，in Proceedings of IEEE 1983 Ultrasonic Symposium，October 31-2 November，1983，Atlanta，GA，pp.581-4.2.Martin Abreu，J.M.，Ceres,R.And Freire,T.,“Ultrasonic Ranging: Envelope Analysis Gives Improved Accuracy”,Sensor Review, Vol.12 No.1,1992,pp.17-21.3.Parrilla， M., Anaya,J.J and Fritsch C.,‖Digital Signal Processing Techniques for High Accuracy Ultrasonic Range Measurement:,IEEE Transactions: Instrumentation and Measurement.Vol.40 No.4, August 1991,pp.750-63.4.Canali, C., Cicco, G.D., Mortem, B., Prudenziati, M., and Taron, A., ―A Temperature Compensated Ultrasonic Sensor Operating in Air for Distance and Proxinmity Measurement‖, IEEE Trasaction on Industry Electronics, Vol, IE-29 No.4,1982, pp.336-41.5.Martin, J.M., Ceres, R., Calderon, L and Freire, T., ‖Ultrasonic Ranging Gets Themal Correction‖, Sensor Review, Vol, 9 No.3, 1989,pp.153-5.中原工學院畢業(yè)設計（論文）譯文

Ultrasonic ranging system design Publication title: Sensor Review.Bradford:1993.Vol.13 ABSTRACT: Ultrasonic ranging technology has wide using worth in many field, such as the industrial locale, vehicle navigation and sonar engineering.Now it has been used in level measurement, self-guided autonomous vehicles, fieldwork robots automotive navigation, air and underwater target detection, identification ,location and so on.So there is an important practicing meaning to learn the ranging theory and ways deeply.To improve the precision of the ultrasonic ranging system in hand, satisfy the request of the engineering personal for the precision,the bound and the usage, a portable ultrasonic ranging system based on the single chip processor was developed.Keywords: Ultrasound r, Ranging System, Single Chip Processor

1.Introductive With the development of science and technology, the improvement of people’s standard of living, speeding up the development and construction of the city.Urban drainage system have greatly developed their situation is constantly improving.However, due to historical reasons many unpredictable factors in the synthesis of her time, the city drainage system.In particular drainage system often lags behind urban construction.Therefore, there are often good building excavation has been building facilities to upgrade the drainage system phenomenon.It brought to the city sewage, and it is clear to the city sewage and drainage culvert in the sewage treatment system.Confort is very important to people’s lives.Mobile robots designed to clear the drainage culvert and the automatic control system Free sewage culvert clear guarantee robot, the robot is designed to clear the culvert sewage to the core.Control System is the core component of the development of ultrasonic range finder.Therefore, it is very important to design a good ultrasonic range finder.1.1 subject background

With the development of economy and car scientific and technological progress, highway traffic presents driving fast pace, traffic dense is changed and the driver not professional trend.At the same time, along with the rapid development of auto industry, automobile yield and quantities are increased dramatically.But road development，中原工學院畢業(yè)設計（論文）譯文

transportation management is relatively backward, leading to a large number of traffic accidents in some cities, especially prominent.Intelligent transportation system in the world, ITS transportation science and technology of advanced technology, ITS exerting existing infrastructure of potential, enhance the transport efficiency, safeguard traffic safety and ease traffic wager plug, improving urban environment aspects of outstanding performance, has received the governments of widespread concern.The Chinese government is also highly intelligent transportation system of the development and popularization applications.The automotive anti-collision system as ITS development of a base, ITS success to the whole system has a very significant role.Traditionally, auto safety said can be divided into two main research direction: first,it is active safety technology, including the prevention of accidents, the way is now automotive safety research ultimate purpose;second, it is passive safety technique, namely the occupant protection after the accident.Now automotive safety field passive safety more research, mainly from the airbag, ABS(antilock brakes)and suspension from the aspects such as to ensure safety of personnel rides.From the economic and safety two ways, these passive safety measures is the accident of vehicle and personnel moments protection, with great limitations, thus vehicle active safety research is particularly important, leads to a of this study is based on single chip ultrasonic ranging system.This system is a kind of can advance to the driver issued audio-visual speech signal detection devices.It is installed in cars that can detect trying to approach the body of a car pedestrians and vehicles or around obstacles, Can send to the driver and crew imminent danger ahead of the signal, prompting a crash drivers take emergency measures to cope with special danger, avoid the loss.1.2 question design significance

Along with the development of modern society industrialization process, car this traffic tools are used for more and more people, but any problem has obvious that along with the increase in vehicles, traffic accident, which led to the frequent occurrence of casualties and property losses number astonishing.For highway traffic accident analysis showed that more than 80% of the accident due to the driver reaction inferior things, caused more than 65% of vehicle collision, the rest belongs to tracing cauda collided belongs to the side collision.Mercedes-benz Automobile Company for all kinds of traffic accident research shows that: if the driver can early 1S are aware

中原工學院畢業(yè)設計（論文）譯文

that a accident risk and take the appropriate corrective measures, the overwhelming majority of traffic accidents can be avoided.Therefore, vigorously research and development as the automotive anti-collision device etc active car auxiliary safe device, reduce the burden and misjudgments drivers to improve the traffic safety will play an important role.Obviously, this kind of product research and development has great realize meaning and broad application prospects.1.3 Ultrasonic ranging in automotive applications introduced

Ultrasonic back-draft rangefinder(known as electron optics)automotive anti-collision reversing device, can safe adjunct to sound or more intuitive digital form the dynamic display of around obstacles.Its earlier products is to use buzzer alarm, hum more anxious, and says vehicles from obstructions closer.Subsequent product can display the car from the body after the obstacles distance.Most of its products detection range in 0.4 ~ 1.5 m, some product can achieve 0.35 ~ 2.5 m, and have distance display, sound alarm, area-warning and azimuth instructions, some products also has the boot self-checking function.Still appeared on the market at present with voice alarm function of products.These products are the main problem is big, alarm measuring blind area lags behind, without considering the automobile braking inertial factors and make drivers brake lag, the anti-interference ability is not strong, misstatement or more.The automotive anti-collision radar is able to realize impact-proof alarm functions, basically have ultrasonic this intangible ruler, it recently obstacles distance measurement, and told to the owner.Actually ultrasonic range-finding principle simple: it emit ultrasonic echo, and receive reflected by microcontroller counter obtain both lag using formula S = t, Ct / 2 calculating distances, including S for cars and obstacles, C for the distance between the sound wave propagation in the medium speed.This paper introduces the ultrasonic ranging system only have 2 ultrasonic transducer(known as probe)respectively, decorate in cars left and right after after 2 position.Capable of detecting forward and reverse direction obstacle distance, the rearview mirror built-in display element display distance and direction, issued must be sound, plays the role of hints and alert.System USES a STC89C52 SCM two way ultrasonic signal cyclicly acquisition.Ultrasonic refers to the 20HHZ wave frequency is over.In order to use the ultrasonic detection means, must generate as ultrasonic wave and receiving damnation.Complete the functions of the device is called the

中原工學院畢業(yè)設計（論文）譯文

ultrasonic sensor, habit, ultrasonic transducer or ultrasonic probe.Ultrasonic sensors have both transmitters and receivers, but a ultrasonic sensors can also has the sending and receiving the sound waves of the dual role.Ultrasonic sensors is using the principle of piezoelectric effect and ultrasonic energy conversion, be in namely emit ultrasonic, energy conversion, launch ultrasonic, And in the stockades, received echo ultrasonic vibration into electrical signal.Ultrasonic ranging principle generally USES the time method for the crossing.First measured ultrasonic from the launch to meet obstacles returns experience of time, again multiply ultrasonic speed of get twice the distance between the sound source and obstacles.Measuring distance a variety of ways, short can use ruler, long-range laser displacement etc, are suitable for high accuracy of ultrasonic ranging in long distance measurement.Because of ultrasound in standard air of propagation speed 331.45 meters per second, by single-chip microcomputer is responsible for timing, SCM use 12.0 M crystals, so the system of measurement precision theory can achieve mm level.Because of ultrasonic directivity strong, energy consumption is slow, in a medium transmission distance, thus ultrasonic can be used for distance measurement.Using ultrasonic detection distance, the design is more convenient, computing procese also relatively simple, and the measurement precision can also meet the requirements.Ultrasonic generator can be divided into two kinds: one kind is to use electrical means producing ultrasonic, one kind is with mechanical approach to producing ultrasonic.This design belongs to nearly distance measurement, can use commonly used the piezoelectric ultrasonic transducer to achieve trigger unit.Using ultrasonic ranging work, can according to measuring launch reflection wave wave and the time interval between the measured distance, so as to achieve the effect.It mainly have three ranging methods:

(1)phase assay, phase assays high precision, but detection though limited range，(2)sound amplitude assay, acoustic amplitude assay vulnerable reflection wave influence;

(3)ferrying more time assay, crossing the time assay way of working is simple, intuitive, in hardware control and software design are very easy to implement.Its principle is: from the launch emit ultrasonic detection sensor, the gas medium spread to receive sensor of time, this time is crossing the more time.This design is the use of ultrasonic ranging the crossing the time assay.In the mobile vehicles of the application 15

中原工學院畢業(yè)設計（論文）譯文

of ultrasonic sensor is the use of ultrasound in air of directional spread and solid reflective characteristics(p-wave)and by receiving their launch ultrasonic reflecting signal, according to the ultrasonic issued and echo receiving the Windows and propagation speed, calculate transmission distance, thus obtains the obstacles to vehicle distance.中原工學院畢業(yè)設計（論文）譯文

2.A principle of ultrasonic distance measurement

2.1 the principle of piezoelectric ultrasonic generator

Piezoelectric ultrasonic generator is the use of piezoelectric crystal resonators to work.Ultrasonic generator, the internal structure as shown, it has two piezoelectric chip and a resonance plate.When it’s two plus pulse signal, the frequency equal to the intrinsic piezoelectric oscillation frequency chip, the chip will happen piezoelectric resonance, and promote the development of plate vibration resonance, ultrasound is generated.Conversely, if the two are not inter-electrode voltage, when the board received ultrasonic resonance, it will be for vibration suppression, then it becomes the ultrasonic receiver.The traditional way to determine the moment of the echo’s arrival is based on thresholding the received signal with a fixed reference.The threshold is chosen well above the noise level, whereas the moment of arrival of an echo is defined as the first moment the echo signal surpasses that threshold.The intensity of an echo reflecting from an object strongly depends on the object’s nature, size and distance from the sensor.Further, the time interval from the echo’s starting point to the moment when it surpasses the threshold changes with the different intensities arriving exactly at the same tome will surpass the threshold at different moments.The stronger one will surpass the threshold earlier than the weaker, so it will be considered as belonging to a nearer object.2.2 The principle of ultrasonic distance measurement Ultrasonic transmitter in a direction to launch ultrasound, in the moment to launch the beginning of time at the same time, the spread of ultrasound in the air, obstracles on his way to return immediately, the ultrasonic reflected wave wave received by the reveiver immediately stop the clock.Ultrasonic in the air as the propagation velocity of 340m/s, according to the timer records the time t, we can calculate the distance between the launch distance barrier(s), that is:s=340t/2

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3.Ultrasonic Ranging System for the Second Circuit Design

System is characterized by single-chip microcomputer to control the use of ultrasonic transmitter and ultrasonic receiver since the launch from time to time, single-chip selection of 8751,economic-to –use, and the chip has 4K of ROM, to facilitate programming.Circuit schematic diagram shown in Figure 1.Figure 1 circuit principle diagram

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3.1 40 kHz ultrasonic pulse generated with the launch

Ranging system using the ultrasonic sensor of piezoelectric sensors UCM40, its operating voltage of the pulse signal is 40kHz, which by the single-chip implementation of the following procedures to generate.Puzel:mov 14h,# 12h;ultrasonic firing continued 200ms here:cpl pl.0;output 40 kHz square wave

nop;

nop;nop;djnz 14h, here;ret Ranging in front of single-chip termination circuit P1.0 input port, single chip implementation of the above procedure, the P1.0 port in a 40kHz pulze output signal, after amplification transistor T, the drive to launch the first ultrasonic UCM40T, issued 40kHz ultrasonic pulse, and the continued launch of 200ms.Ranging the right and the left side of the circuit, respectively, then input port P1.1 and P1.2, the working principle and circuit in front of the same location.3.2 Reception and processing of ultrasonic

Used to receive the first launch of the first pair UCM40R, the ultrasonic pulse modulation signal into an alternating voltage, the op-amp amplification IC1A and after polarization IC1B to IC2.IC2 is locked loop with audio decoder chip LM567, internal voltage-controlled oscillator center frequency of f0=1/1.1R8C3, capacitor C4 determine their target bandwidth.R8-conditioning in the launch of the carrier frequency on the LM567 input signal is greater than 25Mv, the output from the high jump 8 feet into a low-level, as interrupt request signals to the single-chip processing.Ranging in front of single-chip termination circuit port INT0 interrupt the highest priority, right or left location of the output circuit with output gete IC3A access INT1 port single-chip, while single-chip P1.3 and P1.4 received input IC3A, interrupted by the process to identify the source code is as follows: receivel:

push psw

push ace

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cir ex1: related external interrupt 1

jnb p1.1, right;P1.1 pin to 0, ranging from right to interrupt service rountine circuit

jnb p1.2, left;P1.2 pin to 0, to the left ranging circuit

interrupt service routine return:SETB EX1;open external interrupt 1

pop

acc pop

psw reti right:…;right location entrance circuit interrupt service rountine

Ajmp Return left:…;left Ranging entrance circuit interrupt service rountine

Ajmp Return

3.3 The calculation of ultrasonic propagation time

When you start firing at the same time start the single-chip circuitry within the timer T0, the use of timer counting function records the time and the launch of ultrasonic reflected wave received time when you receive the ultrasonic reflected wave, the receiver circuit outputs a negative jump in the end of INT0 or INT1 interrupt request generates a signal, single-chip microcomputer in response to external interrupt request, the implementation of the external interrupt service subroutine, read the time difference, calculating the distance.Some of its source is as follows: RECEIVE0: PUSH PSW PUSH ACC CLR EX0;related external interrupt 0 MOV R7, TH0;read the time value MOV R6, TL0 CLR C MOV A, R6 SUBB A,#0BBH;calculate the tome difference MOV 31H, A;storage results MOV A, R7 SUBB A,#3CH

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MOV 30H,A SETB EX0;open external interrupt 0 POP ACC POP PAW RETI For a flat target, a distance measurement consists of two phases: a coarse measurement and, a fine measurement: Step 1: Transmission of one pulse train to produce a simple ultrasonic

Wave.Step 2: Changing the gain of both echo amplifiers according to equation，until the echo is detected.Step 3:detection of te amplitudes anf zero-crossing times of both echoes.Step 4:setting the gains of both echo amplifiers to normalize the output at, say 3 volts.Setting the period of the next pulses according to the: period of echoes.Setting the time window according to the data of step 2.Step 5:sending two pulse trains to produce an interfered wave.Testing the zero-crossing in the echo,detemine to otherwise calculate to by interpolation using the amplitudes near the trough.Derive t sub ml and t sub m2.Step6: Calculation of the distance y using equation.中原工學院畢業(yè)設計（論文）譯文

4.The ultrasonic ranging system software design

Software is divided into two parts, the main program and interrupt service routine.Completion of the work of the main program is initialized, each sequence of ultrasonic transmitting and receiving control.Tnterrupt service routines from time to complete three of the rotation direction of ultrasonic launch, the main external interrupt service subroutine to resd the value of completion time, distance calculation, the results of the output and so on.中原工學院畢業(yè)設計（論文）譯文

5.Conclusions

Required measuring range of 30cm~200cm objects inside the plane to do a number of measurements found that the maximum error is 0.5cm, and good reproducibility.Single-chip design can be seen on the ultrasonic ranging system has a hardware structure is simple, reliable, small features such as measurement error.Therefore, it can be used not only for mobile robot can be used in other detection systems.Thoughts: As for why the receiver do not have the transistor amplifier circuit, because the magnification well, integrated amplifier, but also with automatic gain control level, magnification to 76dB, the center frequency is 38k to 40k, is exactly resonant ultrasonic sensors frequency.中原工學院畢業(yè)設計（論文）譯文

REFERENCES 1.Fox,J.D.,Khuri-Yakub, B.T.and Kino, G.S., ‖High Frequency Acoustic Wave Measurement in Air‖, in Proceedings of IEEE 1983 Ultrasonic Symposium, October 31-2 November, 1983, Atlanta, GA, pp.581-4.2.Martin Abreu,J.M.,Ceres,R.and Freire, T.,‖Ultrasonic Ranging: Envelope Analysis Gives Improved Accuracy‖, Sensor Review, Vol.12No.1,1992, pp.17-21.3.Parrilla， M., Anaya,J.J and Fritsch C.,‖Digital Signal Processing Techniques for High Accuracy Ultrasonic Range Measurement:,IEEE Transactions: Instrumentation and Measurement.Vol.40 No.4, August 1991,pp.750-63.4.Canali, C., Cicco, G.D., Mortem, B., Prudenziati, M., and Taron, A., ―A Temperature Compensated Ultrasonic Sensor Operating in Air for Distance and Proxinmity Measurement‖, IEEE Trasaction on Industry Electronics, Vol, IE-29 No.4,1982, pp.336-41.5.Martin, J.M., Ceres, R., Calderon, L and Freire, T., ‖Ultrasonic Ranging Gets Themal Correction‖, Sensor Review, Vol, 9 No.3, 1989,pp.153-5.24

第五篇：外文翻譯

Low Voltage Flyback DC-DC Converter For

Power Supply Applications Hangzhou Liu1, John Elmes2, Kejiu Zhang1, Thomas X.Wu1, Issa Batarseh1

Department of Electrical Engineering and Computer Science, University of Central Florida, Orlando, FL 32816, USA Advanced Power Electronics Corporation, Orlando, FL 32826, USA Abstract ：In this paper, we design a low voltage DC-DC converter with a flyback transformer.The converter will be used as a biased power supply to drive IGBTs.The flyback transformer using planar EI-core is designed and simulated using ANSYS PExprt software.Besides, anLT3574 IC chip from Linear Technology has been chosen for converter control.Finally, the converter modeling and simulation are presented and PCB layout is designed.Keywords：Flyback, anLT3574IC, PCB

I.INTRODUCTION The goal of this project is to develop and build a prototype of a high-efficiency, high-temperature isolated DC-DC converter to be used as a biased power supply for driving a complementary IGBT pair.It is important that the converter can deliver the required power at an ambient temperature of up to 100℃;therefore it has to be efficient so that its components do not exceed their maximum temperature ratings.The final converter will be completely sealed and potted in a metal case.The input voltage range for this converter is from 9V to 36V.The output sides have two terminals, one is﹢16V and the other one is﹣6V.In order to get the desired performance, anLT3574 IC chip from Linear Technology is used.The key to this design is the flyback transformer.The transformer using planar EI-core is designed and simulated using ANSYS PExprt software.Finally, the PCB layout of the converter will be presented.II.KEY DESIGN OUTLINE For this flyback topology, the output voltage can be determined by both the transformer turns ratio and the flyback loop resistor pairs.Therefore, at the initial design stage, we can choose a convenient turn’s ratio for the transformer, and modify it later on if necessary to make sure the output performance is desirable and the transformer will not saturate [1].The relationship between transformers turns ratio and duty cycle can be found as

Where n is the transformer turns ratio, D is the duty cycle, VO` is the sum of the output voltage plus the rectifier drop voltage, VIN is the input voltage of the transformer.The value of feedback resistor can be calculated as

Where RREF is the reference resistor, whose value is typically 6.04k?;α is a constant of 0.986;VBG is the internal band gap reference voltage, 1.23V;and VTC is normally 0.55V [1].With a specific IC chosen, the converter circuit can be designed based on a demo circuit and some parameters may need to be modified if necessary to optimize the performance.Furthermore, in LT Spice, a large number of simulations need to be done with different conditions such as load resistor values and input voltage levels.It is important to make sure that the output voltage can be regulated well with all these different conditions.The most critical part of the design is the flyback transformer.With high switching frequency, the AC resistance can only be estimated based on some traditional methods such as Dowell’s curve rule [2].In order to get more accurate values of AC resistance values;we propose to use finite element electromagnetic software ANSYS PExprt to do the design [3].At the initial design stage, key parameters such as the worst-case input voltage, frequency, material, inductance values will be decided.After that, these data will be imported to the software, from which an optimized solution will be generated.III.CONVERTER SIMULATION RESULTS We choose LT3574 chip in this design.From the simulation results in Figure 1 and Table 1, it clearly shows that the output voltages which are﹢16V and-6V respectively can be regulated pretty well with the input voltage range from 9V to 36V.The voltage tolerance ranges are from ﹢15V to ﹢19V and-12V toDC converter for low voltage power supply application has been designed.The modeling and simulation results are presented.Based on the design specifications, a suitable IC from Linear Technology is chosen.A large amount of circuit simulations with different conditions such as load resistor values and input voltage levels are presented to get the desirable output voltage and current performance.The transformer has been designed including electrical, mechanical and thermal properties.With all the specific components decided, the PCB layout of the converter has been designed as well.REFERENCE

[1] Linear Technology Application Notes , Datasheet of Isolated Flyback Converter Without an Opto-Coupler, http://cds.linear.com/docs /Datasheet/3574f.pdf.[2] P.L.Dowell, “Effect of eddy currents in transformer windings” Proceedings of the IEE, NO.8 PP.1387-1394, Aug 1966.[3] S.Xiao, “Planar Magnetics Design for Low-Voltage DC-DC Converters” MS, 2004.[4] ANSYS Application Notes, PEmag Getting Started: A Transformer Design Example, http://004km.cn/download/ EDA/Maxwell9/planarGS0601.pdf.[5] K.Zhang;T.X.Wu;H.Hu;Z.Qian;F.Chen.;K.Rustom;N.Kutkut;J.Shen;I.Batarseh;“Analysis and design of distributed transformers for solar power conversion” 2011 IEEE Applied Power Electronics Conference and Exposition(APEC), v l., no., pp.1692-1697, 6-11 March 2011.[6] Zhang.;T.X.Wu.;N.Kutkut;J.Shen;D.Woodburn;L.Chow;W.Wu;H.Mustain;I.Batarseh;,“Modeling and design optimization of planar power transformer for aerospace applic ation,” Proceedings of the IEEE 2009 National, Aerospace & Electronics Conference(NAECON), vol., no., pp.116-120, 21-23 July 2009.[7] Ferroxcube Application Notes, Design of Planar Power Transformer,