Consider two simple games played by Alice and Bob on a checkerboard or, more generally, on a graph. The games look different, but, as we know, looks can be deceiving…
{"title":"Puzzled: Paths and Matchings","authors":"Peter Winkler","doi":"10.1145/2631198","DOIUrl":"https://doi.org/10.1145/2631198","url":null,"abstract":"Consider two simple games played by Alice and Bob on a checkerboard or, more generally, on a graph. The games look different, but, as we know, looks can be deceiving…","PeriodicalId":10645,"journal":{"name":"Commun. ACM","volume":"362 1","pages":"104"},"PeriodicalIF":0.0,"publicationDate":"2014-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80277830","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We present JMB, a joint multiuser beamforming system, that enables independent access points (APs) to beamform their signals and communicate with their clients on the same channel as if they were one large MIMO transmitter. The key enabling technology behind JMB is a new low-overhead technique for synchronizing the phase of multiple transmitters in a distributed manner. The design allows a wireless LAN to scale its throughput by continually adding more APs on the same channel. JMB is implemented and tested with both software radio clients and off-the-shelf 802.11n cards, and evaluated in a dense congested deployment resembling a conference room. Results from a 10-AP software-radio testbed show a linear increase in network throughput with a median gain of 8.1--9.4×. Our results also demonstrate that JMB's joint multiuser beamforming can provide throughput gains with unmodified 802.11n cards.
{"title":"JMB: scaling wireless capacity with user demands","authors":"Hariharan Rahul, Swarun Kumar, D. Katabi","doi":"10.1145/2618413","DOIUrl":"https://doi.org/10.1145/2618413","url":null,"abstract":"We present JMB, a joint multiuser beamforming system, that enables independent access points (APs) to beamform their signals and communicate with their clients on the same channel as if they were one large MIMO transmitter. The key enabling technology behind JMB is a new low-overhead technique for synchronizing the phase of multiple transmitters in a distributed manner. The design allows a wireless LAN to scale its throughput by continually adding more APs on the same channel. JMB is implemented and tested with both software radio clients and off-the-shelf 802.11n cards, and evaluated in a dense congested deployment resembling a conference room. Results from a 10-AP software-radio testbed show a linear increase in network throughput with a median gain of 8.1--9.4×. Our results also demonstrate that JMB's joint multiuser beamforming can provide throughput gains with unmodified 802.11n cards.","PeriodicalId":10645,"journal":{"name":"Commun. ACM","volume":"50 1","pages":"97-106"},"PeriodicalIF":0.0,"publicationDate":"2014-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87126442","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jane Margolis, J. Goode, Gail Chapman, Jean J. Ryoo
Effective teaching practices for broadening participation in computer science.
扩大计算机科学参与的有效教学实践。
{"title":"That classroom 'magic'","authors":"Jane Margolis, J. Goode, Gail Chapman, Jean J. Ryoo","doi":"10.1145/2618107","DOIUrl":"https://doi.org/10.1145/2618107","url":null,"abstract":"Effective teaching practices for broadening participation in computer science.","PeriodicalId":10645,"journal":{"name":"Commun. ACM","volume":"24 1","pages":"31-33"},"PeriodicalIF":0.0,"publicationDate":"2014-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79696570","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Considering the opportunities and challenges for commercial firms involved with government business process outsourcing.
考虑参与政府业务流程外包的商业公司的机遇和挑战。
{"title":"The business of the state","authors":"M. Sako","doi":"10.1145/2618105","DOIUrl":"https://doi.org/10.1145/2618105","url":null,"abstract":"Considering the opportunities and challenges for commercial firms involved with government business process outsourcing.","PeriodicalId":10645,"journal":{"name":"Commun. ACM","volume":"37 1","pages":"28-30"},"PeriodicalIF":0.0,"publicationDate":"2014-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91182812","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The Communications Web site, http://cacm.acm.org, features more than a dozen bloggers in the BLOG@CACM community. In each issue of Communications, we'll publish selected posts or excerpts.
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http://cacm.acm.org/blogs/blog-cacm
Mark Guzdial considers the "poor learnability" of programming languages, while Philip Guo enumerates some practical benefits to working in a CS lab.
{"title":"The difficulty of teaching programming languages, and the benefits of hands-on learning","authors":"M. Guzdial, Philip J. Guo","doi":"10.1145/2617658","DOIUrl":"https://doi.org/10.1145/2617658","url":null,"abstract":"The <i>Communications</i> Web site, http://cacm.acm.org, features more than a dozen bloggers in the BLOG@CACM community. In each issue of <i>Communications</i>, we'll publish selected posts or excerpts.<br /><br /><b>twitter</b><br /><b>Follow us on Twitter at http://twitter.com/blogCACM</b><br /><br /><b>http://cacm.acm.org/blogs/blog-cacm</b><br /><br />Mark Guzdial considers the \"poor learnability\" of programming languages, while Philip Guo enumerates some practical benefits to working in a CS lab.","PeriodicalId":10645,"journal":{"name":"Commun. ACM","volume":"1 1","pages":"10-11"},"PeriodicalIF":0.0,"publicationDate":"2014-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82180415","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Optical tricks help deceased entertainers keep on performing.
光学技巧帮助已故艺人继续表演。
{"title":"Holographic projection systems provide eternal life","authors":"Esther Shein","doi":"10.1145/2617664","DOIUrl":"https://doi.org/10.1145/2617664","url":null,"abstract":"Optical tricks help deceased entertainers keep on performing.","PeriodicalId":10645,"journal":{"name":"Commun. ACM","volume":"19 1","pages":"19-21"},"PeriodicalIF":0.0,"publicationDate":"2014-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80401755","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Professional organizations should be in the forefront of the ongoing discussion about licensing professional software engineers.
专业组织应该站在正在进行的关于专业软件工程师许可的讨论的前沿。
{"title":"Licensing professional software engineers: seize the opportunity","authors":"P. Laplante","doi":"10.1145/2618111","DOIUrl":"https://doi.org/10.1145/2618111","url":null,"abstract":"Professional organizations should be in the forefront of the ongoing discussion about licensing professional software engineers.","PeriodicalId":10645,"journal":{"name":"Commun. ACM","volume":"46 37 1","pages":"38-40"},"PeriodicalIF":0.0,"publicationDate":"2014-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72661476","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Next-generation scientific instruments are forcing researchers to question the limits of massively parallel computing.
下一代科学仪器迫使研究人员质疑大规模并行计算的极限。
{"title":"Big data meets big science","authors":"A. Wright","doi":"10.1145/2617660","DOIUrl":"https://doi.org/10.1145/2617660","url":null,"abstract":"Next-generation scientific instruments are forcing researchers to question the limits of massively parallel computing.","PeriodicalId":10645,"journal":{"name":"Commun. ACM","volume":"71 1","pages":"13-15"},"PeriodicalIF":0.0,"publicationDate":"2014-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91445315","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The ABC vs. Aereo case has potentially far-reaching consequences.
ABC诉Aereo案可能会产生深远的影响。
{"title":"Watching TV on internet-connected devices","authors":"Pamela Samuelson","doi":"10.1145/2618099","DOIUrl":"https://doi.org/10.1145/2618099","url":null,"abstract":"The ABC vs. Aereo case has potentially far-reaching consequences.","PeriodicalId":10645,"journal":{"name":"Commun. ACM","volume":"36 1","pages":"22-24"},"PeriodicalIF":0.0,"publicationDate":"2014-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82773240","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Matthew Faulkner, Rob Clayton, T. Heaton, K. Chandy, M. Kohler, J. Bunn, Richard Guy, Annie H. Liu, Michael Olson, M. Cheng, Andreas Krause
The Caltech CSN project collects sensor data from thousands of personal devices for real-time response to dangerous earthquakes.
加州理工学院的CSN项目从数千个个人设备收集传感器数据，用于对危险地震的实时响应。
{"title":"Community sense and response systems: your phone as quake detector","authors":"Matthew Faulkner, Rob Clayton, T. Heaton, K. Chandy, M. Kohler, J. Bunn, Richard Guy, Annie H. Liu, Michael Olson, M. Cheng, Andreas Krause","doi":"10.1145/2622633","DOIUrl":"https://doi.org/10.1145/2622633","url":null,"abstract":"The Caltech CSN project collects sensor data from thousands of personal devices for real-time response to dangerous earthquakes.","PeriodicalId":10645,"journal":{"name":"Commun. ACM","volume":"16 1","pages":"66-75"},"PeriodicalIF":0.0,"publicationDate":"2014-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78749895","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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