天堂島精品??_國產亞洲精品久久久久久鴨綠欲??_.手.動.輸.入.網.址.聯.系.客.服.人.員.lanan_shell
Firewall Over-the-air Cellular Infrastructure Internet WAN Wireless Ground Base Station Flight Data Ground Station Automatic Data Transfer to AirFASE? High Speed Internet Service Provider Flight Data Monitoring Efficiency Internet Service Provider FDM Tools are Ready for General Aviation Questions? Fourth Quarter 2004 61 b o o k e x c e r p t C The New Division of Labor How Computers are Creating the Next Job Market by frank l ev y and richard murnane Computers – can’t live with ’em, can’t live without ’em. Yes, I’m paraphrasing a hoary joke that wasn’t very funny in the fi rst place. But it really does apply to the machines that both make us rich and drive us mad. ? Frank Levy and Richard Murnane, economists at MIT and Harvard respectively, offer a cool analysis of a hotly debated issue: how to reap the benefi ts of computers in the workplace without paying a heavy price in terms of displaced workers. And the prognosis, they suggest, is guardedly optimistic. Coping with the social consequences of “the hollowing out of the occupational distribution,” they argue, will require job training that focuses on what computers do least well – expert communication and complex thinking. — Peter Passell *Published by Princeton University Press. All rights reserved. ira block/ipn/aurora 62 The Milken Institute Review When the model was completed and the blueprints had been corrected, design engineers translated blueprint specifi cations into settings for stamping presses, turning lathes and the other machine tools that would fabricate the 727’s parts. The translation resulted in many small errors and the parts often fi t imperfectly. Assembly workers had to adjust the parts by hand, using metal shims to fi ll in small gaps. A manager familiar with the process estimated that a 727 weighing 44 tons typically contained a half-ton of shims. In April 1994 Boeing rolled out the 777, a 305-passenger plane designed to fl y up to 6,000 miles. Although much larger and more complex than the 727, the 777’s development cycle was shorter by 29 months. The explanation was no secret: the 777 was the fi rst commercial jet to be completely designed using computers. Employing CATIA, computerassisted design and manufacturing software developed by the French company Dassault Systèmes, engineers created components on computer screens rather than on paper. The software’s power was its ability to integrate individual views into three dimensions. The virtual model substituted for a physical mockup in checking plans for internal consistency. Once engineers had corrected the plans, CATIA produced the digital settings for the computer numerical controlled (CNC) machine tools that would fabricate the 777’s parts. Boeing purchased the CATIA system as part of an effort to pursue several competitive strategies. One was to compete better by increasing design speed. Being fi rst to market is particularly important in civilian aircraft, where two large producers – Boeing and Airbus – vie for a limited number of orders. Boeing’s adoption of CATIA eliminated the need for mock-up models and reduced the time required to correct plans and to set up machine tools. A second competitive strategy facilitated by CATIA was improved product quality. The digital settings that CATIA produced for CNC machine tools made it possible to produce parts that fi t together well, so the 777’s assembly required far fewer hand adjustments and shims. In November 1962, Boeing launched the 727, a 131-passenger jetliner designed to operate out of small airports with short runways. The rollout completed an 81-month development process during which more than 5,000 engineers worked with thousands of pounds of blueprints to design an aircraft that included more than 100,000 parts. The airplane’s complexity meant that no one person could guarantee the blueprints’ internal consistency, and so the second step in the design process was the construction of a full-scale model to ensure that the components fi t – that proper space had been left for the aircraft’s seats, hydraulic lines, air-conditioning ducts and other components. Fourth Quarter 2004 63 CATIA also made it possible for Boeing to compete by confi guring to customers’ specifi - www.aero.cn 航空翻譯 www.aviation.cn 本文鏈接地址：航空資料22
