tag:blogger.com,1999:blog-9186457242428335144.post3032899340371838579..comments2024-03-18T23:39:02.190-07:00Comments on Volatile and Decentralized: The Future of Sensor NetworksMatt Welshhttp://www.blogger.com/profile/04255792550910131960noreply@blogger.comBlogger11125tag:blogger.com,1999:blog-9186457242428335144.post-65038046273153543812010-10-13T11:11:36.932-07:002010-10-13T11:11:36.932-07:00Hello.. Firstly I would like to send greetings to ...Hello.. Firstly I would like to send greetings to all readers. After this, I recognize the content so interesting about this article. For me personally I liked all the information. I would like to know of cases like this more often. In my personal experience I might mention a book called Green Parks Costa Rica in this book that I mentioned have very interesting topics, and also you have much to do with the main theme of this article.Green Parkshttp://greenparkscr.com/Inicio.htmlnoreply@blogger.comtag:blogger.com,1999:blog-9186457242428335144.post-53762598479074336132010-10-07T06:35:42.587-07:002010-10-07T06:35:42.587-07:00If MAC layers were a "finished" area, we...If MAC layers were a "finished" area, we'd expect to have extensive support for various MAC layers in our operating systems.Viagra Onlinehttp://www.safemeds.com/noreply@blogger.comtag:blogger.com,1999:blog-9186457242428335144.post-31171782304083407662010-09-06T06:15:20.003-07:002010-09-06T06:15:20.003-07:00This comment has been removed by the author.Unknownhttps://www.blogger.com/profile/09961965302993264775noreply@blogger.comtag:blogger.com,1999:blog-9186457242428335144.post-87157792630585723842010-09-06T06:09:47.275-07:002010-09-06T06:09:47.275-07:00asdasdAnonymousnoreply@blogger.comtag:blogger.com,1999:blog-9186457242428335144.post-44433854940917403232009-11-15T11:43:34.483-08:002009-11-15T11:43:34.483-08:00Matt: I wasn't specifically referring to you w...Matt: I wasn't specifically referring to you when I reacted to the "MACs are done" idea - I was thinking more about the community in general, where a lot of people seem to have this idea. But I completely agree with you that I would not recommend any one to go all-in on MAC layer research. With a duty cycle of < 1% (by many MAC protocols), it is hard to improve state of the art in the area. Yet, people should not forget their tremendous importance.<br /><br />I believe the sweet spot for SenSys would be in the combination of the systems and low-level aspects that it currently has, with the interesting applications emerging from the union of traditional ubicomp systems, the "Internet of Things" (sensors and actuators moving into everyday objects and scenarios), "cyber physical systems", and real-world aspects promoted by the IPSO Alliance and their likes. There are a great deal of interesting problems hiding in there. <br /><br />Your list of open problems is very good. I would also add integration and interaction with existing large-scale systems to the list. When large-scale data input from large numbers of devices meets large-scale data management, there are interesting questions to be asked: for example, where and by whom should data filtering be performed (if at all)? Questions like those cannot be completely answered by looking only at the sensor network, but must involve the outside world as well.jkpnoreply@blogger.comtag:blogger.com,1999:blog-9186457242428335144.post-76473147188050433802009-11-15T10:55:02.529-08:002009-11-15T10:55:02.529-08:00jkp - I never said that MAC protocols were "d...jkp - I never said that MAC protocols were "done", just "well-trodden", which is not the same thing. If I were talking to a new faculty member about what research direction to head in, I think recommending that they work on MAC protocols would be very risky. It's unlikely that you can publish such work in a major conference (unless you make a pretty major breakthrough, though I'm not sure there are major breakthroughs yet to be made in that area), and given the large amount of mediocre research on MAC protocols it is hard to stand out. It is a very crowded space.<br /><br />I do agree that SenSys has taken a strong systems stance that is valuable and should not be abandoned. As we start branching out it is important to maintain the high degree of rigor that we have established in that community.Matt Welshhttps://www.blogger.com/profile/04255792550910131960noreply@blogger.comtag:blogger.com,1999:blog-9186457242428335144.post-77583515514543574242009-11-15T10:45:30.946-08:002009-11-15T10:45:30.946-08:00Matt: great point regarding MAC protocols and low-...Matt: great point regarding MAC protocols and low-level services. But there is a risk in us repeatedly saying that one particular area is complete, when there are still things to be done in that area. I dare to say that MAC protocols are one of the strongest contributions that the sensor networking community has done: they allow us to treat the sensor network as a network, while still maintaining a low power consumption. Some of the early work on sensor networks investigated other ways to view the sensor network, where nodes were sleeping and unavailable. With a MAC protocol, we do not need to handle that complexity any more - we just run our sensors as a network.<br /><br />I agree that low-level mechanisms aren't the bright and glorious future for sensor networks. Low-level mechanisms seldom are. Yet, much of the strength of the sensor network field comes from these numerous low-level aspects: things like stable operating systems and MAC layers to available hardware designs is what has made this community so strong.<br /><br />Compare this to the ubicomp camp, which traditionally has put more value in a cool demo than on low-level technology. Thus the community has showcased many cool demos, but has produced very little of usable technology.<br /><br />I agree that the sensor networking community should turn our eyes away from our belly buttons and towards the skies. But we shouldn't forget that the low-level details still are important when building torwards the next-generation opportunities.jkpnoreply@blogger.comtag:blogger.com,1999:blog-9186457242428335144.post-46498024220572039862009-11-15T10:35:04.264-08:002009-11-15T10:35:04.264-08:00jkp - I will come right out and say that MAC proto...jkp - I will come right out and say that MAC protocol design, while somewhat interesting, is clearly not what is going to carry the sensor networks community for the next decade. If our focus remains only on low-level services we are going to miss a huge opportunity to have an impact on the rest of the world and the future of the Internet. I argue that there are MAC protocols that are "good enough" to take us to the next level; just like TCP/IP was "good enough" to support the tremendous impact of the Internet. Arguably the Web - which started as a dumbed-down ASCII protocol - is what made the Internet happen, not some arcane tweak to TCP congestion control. Personally I think it's time to get our heads out of the sand and look beyond the little camps we've formed in the sensor network community, and start talking about where the next big opportunities lie. MAC protocols ain't it.Matt Welshhttps://www.blogger.com/profile/04255792550910131960noreply@blogger.comtag:blogger.com,1999:blog-9186457242428335144.post-7554477258280702762009-11-15T09:47:53.992-08:002009-11-15T09:47:53.992-08:00Interesting post!
The community seems to generall...Interesting post!<br /><br />The community seems to generally consider the MAC layer an area that does not need to be further investigated. But if this would have been the case, we would expect to have a large number of different, functional MAC layers around. We would also expect that everyone would always use power-saving MAC layers in all their experiments. The MAC layer makes all the difference in terms of power consumption: run your system with no power-saving MAC layer, and it dies in a few days. Use a power-saving MAC layer, and it can live for years.<br /><br />If MAC layers were a "finished" area, we'd expect to have extensive support for various MAC layers in our operating systems. But TinyOS only supports LPL and defaults to running with no MAC layer. And Contiki provides only two: LPL (X-MAC) and optionally LPP (low-power probing). <br /><br />To a large extent, a great deal of papers completely disregard the MAC layer. The authors run experiments using an always-on radio protocol, thus depleting their battery in days. Such systems would never work in any kind of real reployment, yet TPCs continue to let those papers through. Maybe this is because the MAC layer has become such a dreaded area that authors feel that if they mention the MAC layer, their paper will be immediately rejected?<br /><br />Perhaps it is time for the community to rethink our standpoint on MAC protocols?jkpnoreply@blogger.comtag:blogger.com,1999:blog-9186457242428335144.post-6159879593141921122009-11-15T05:17:38.254-08:002009-11-15T05:17:38.254-08:00Of course Culler was not the first - but he is kno...Of course Culler was not the first - but he is known to say this. I'll clarify.Matt Welshhttps://www.blogger.com/profile/04255792550910131960noreply@blogger.comtag:blogger.com,1999:blog-9186457242428335144.post-48255492058033932112009-11-15T03:58:47.939-08:002009-11-15T03:58:47.939-08:00I think the quote is something like "In scien...I think the quote is something like "In science, people stand on the shoulders of giants. In computer science, we stand on each other's toes". And it certainly wasn't David Culler who said it first.Anonymousnoreply@blogger.com