Peerdal

The day a rejected paper will end up in court

2012-02-09T15:43:00.000+01:00

Conferences are no longer nice meetings among gentlemen who care about science. They are the center of a huge competition for thousands of scientists. An acceptance in a major conference can change the career of a scientist and the daily life of a laboratory. It is money and it is fame.

The goal of the peer-reviewing process has naturally shifted from validating the accuracy of a scientific work to selecting a subset of papers. The reviewers have mutated into hunters tracking any reason to crush a paper. All the gentle and polite manners from "guides of peer-reviewing" sound so XXth century. In computer sciences, the "hypercriticality" of scientists is well identified.

Unfortunately, all harsh reviewers are not gifted. Reasons for rejecting a paper frequently come from wrong beliefs, from major misunderstanding or from an obsession for a tiny flaw. These are negative badly-justified reviews, which sometimes make the authors speculate about a possible bias in the reviewing process: the reviewer was a competitor in the same domain, the reviewer was not an expert, the reviewer had personal grievances against the authors, the reviewer was a well-established scientist who does not want to see any newcomer out there...

What are the options for an angry author with a supposed unfairly-reviewed paper and its negative consequences (the money loss and the degraded career)? Let's call a lawyer.

The roles of every entity involved in the traditional academic process are well summarized in this nice paper. Sometimes, the editor of the venue describes the process in used. But the reality is that there is no well-defined rule, no engagement. In fact, it is written nowhere that every paper should be fairly reviewed. An author can only hope that the process is fair because the process is usually said to be fair. I have actually no idea what a lawyer could do versus a no-rule process.

I have always been astonished by Boeing (or Airbus) appealing a decision from an orderer when their bid is rejected. In my naive vision, how can anybody challenge the decision of a private company? When the orderer is the Air Force, there must be rules, for sure, but the idea is the same for a paper to, say, Infocom. But here is the point. There is no Infocom. More precisely, our beloved top-conferences might belong to anybody, including Infocom. I am not sure to know what a lawyer could do versus a no-entity.

Is is serious?

The rebuttal process is probably a good idea, which has the potential to reduce some unfair decisions. But it is still another prehistoric practice based on oral tradition and informal discussions between those who are supposed to be the owner of something that does not exist, except in author's mind. In medicine, some scientists have argued about the creation of a "supreme court" whose role would be to "judge the judges" (here and there). But the motivation is to prevent new scandals related to misbehaving editors. This court would deal with serious cases, not slightly unfair reviews. Maybe academics should look at what has been done in sports to legally organize the structures. Societies like IEEE or ACM could also consider to create a "mediator committee".

Otherwise a rejected paper will end up in court, then who knows who might be considered as responsible.

Incremental improvements for CS conferences

2011-11-28T21:40:00.001+01:00

Scientists like to debate about the general organization of academic life. Lately, some have called for a clean-slate revolution based on open archives. Yet, as for the majority of clean-slate proposals on well-established processes, I am doubtful that such a shift can occur. But in the meantime, nothing is done to actually fix the issues of the current process. In particular, I have the feeling that academic conferences in computer science (at least in my communities, which span networking, multimedia and distributed systems) are getting worse, and it seems that nobody cares because the most active researchers in this area are too busy preparing their utopian clean-slate revolution.

So, let me try to give below four incremental improvements that every serious conference should implement, for the sake of a better academic life. Two are quite easy:

no more deadline extension. A deadline extension is the irrefutable proof that a conference is crappy. A deadline extension means indeed that either the conference does not attract enough solid submissions or the scientists who submit in this conference are unable to finish a work on time. In both cases, it would be a shame to be associated with such a conference. Furthermore deadline extensions bring at least three very negative effects.

it creates an unfair gap between the happy fews who are in the awareness and the others. A scientist who knows in July 2011 that ICC deadline will be Sep 28 has a different schedule than the other scientist who naively thinks the deadline is Sep 6.
it is now folklore to announce an extension a few hours before the deadline. This is highly irrespecutful for the (unaware) authors. Week-ends can be ruined to fulfill a deadline, which you discover on Monday has been extended for two weeks.
the day before a submission is stressful. A (lately announced) deadline extension multiplies the number of deadline-stressful days by two. Deadline extensions are killing me.

a list of accepted papers on the conference webpage the day of the notification. Why is it so hard? An ugly txt-formatted list of accepted papers is just what most scientists want for. From such a list, it is possible to find a link toward an ArXiV or a technical report on the webpages of the authors of accepted papers. Moreover, titles are inspiring, the sooner every scientist can read the titles, the more inspiring it is. And don't forget curiosity of course. Who did pass the cut this year?

Two other improvements are less incremental, but I think their impact would be worth.

no blindness at all. The debate about single vs. double blind is a classic. But very few scientists discuss the blindness of reviewers. There is however a raise of complains about the reviews that are too harsh, scientifically wrong and impolite. It is not hard to believe that if the reviews were signed by their authors, they would be written more carefully. Some argue that this would bring potential desires of revenge among scientists. This ridiculous argument assumes that scientists are no better than kids unable to recognize argued criticisms and unable to retain their negative thoughts. If you are not optimistic about human nature, you should notice that research communities are enlarging. So, the revenge desires of a few bad scientists have really few chances to affect you because the probability that these bad guys represent a majority of reviewers for one of your paper is actually very low. Not mentioning that, academic revengers being stupid people, they are probably not in the committees of top-conferences, so you have nothing to lose. And if you face a majority of reviewers who want to unfairly reject your papers because of your previous bad reviews, well it may be time to consider writing better reviews.
open access to papers. I have already signed this pledge about open access. I know that academic professional societies (ACM, IEEE and so) have to re-invent themselves but we will not wait them to do it. We cannot degrade the quality of the scientific activity just because a few jobs are in stake.

I think it is the role of the program committee members to alert their chairmen that the academic life would be far better if conferences stick to these simple rules.

What's up in networks (3/3): dash

2011-11-09T23:18:00.000+01:00

The last post in this mini-series. After openFlow and hetnets, here is dash.

DASH or Dynamic Adaptive Streaming over HTTP
Although it is not exactly what the MPEG scientists have promoted for a decade, most of today's video traffic is based on HTTP and TCP (Netflix player, Microsoft Smooth Streaming and Adobe OSMF). And it works. The video traffic is exploding: adaptive streaming already represents more than one third of the Internet traffic at peak time, and it is expected to prevail, even on mobiles. Facing this plebiscite, the MPEG consortium has launched the process of standardizing DASH into MPEG.

In short, for a given movie, the video server publishes a manifest file in which it declares several video formats. Each format corresponds to a certain encoding, so a certain quality and a certain bit-rates. All these different videos of the same movie are cut into chunks. A client requesting a movie selects a given video format and then starts downloading the chunks. On a periodic manner, the client tries to estimate whether this video encoding fits the capacity of the network link between her and the server. If she is not satisfied, she considers switching to another encoding for the next chunks. What is the best chunk size, how to estimate the link capacity, what is the best delay between consecutive estimation, how to react to short-term bandwidth changes, how to switch to another encoding… are among the questions that have not received the attention of the scientific community, so every DASH client implements some magic parameters without any concern for potential impacts on the network.

Despite the multimedia scientific community and the video standardization group are large lively communities, many research issues related to DASH have not been anticipated and sufficiently addressed. Among them, I highlight:

When several concurrent DASH connections share the same bottleneck, the congestion control mechanism of TCP may be compromise. In fact, a DASH connection is based on TCP, which implements an adaptive congestion control with proven convergence toward a fair sharing of the bottleneck among concurrent connections. By incessantly adapting the flow bit-rate DASH may prevent the convergence of TCP. If network bottlenecks locate on links that are shared by hundreds of concurrent DASH flows, the lack of convergence of the congestion control mechanism is a risk. I may overestimate the impact, but at least understanding the impact of DASH adaptive policy (which seems to use a lot of random parameter settings) on the eventual convergence of a congestion control policy is an exciting scientific topic.
When multiple servers store different video encodings of the same movie, the client may incessantly switch from a video encoding to another. A DASH connection works especially well when the bottleneck is always the same, whatever the chosen video encoding. In this case, the adaptive mechanism converges toward the video encoding that fits the bottleneck capacity. But in today's Internet, the content can be located in various distinct locations: CDN servers, Internet proxies, and content routers with caching capabilities. If the links toward the different encodings have different congestion level, the DASH adaptive algorithm may become crazy.
A DASH connection does not support swarming. Swarm downloading (one client fetching a large video content from multiple servers) was expected to be enabled by both the multiple copies of the same content and the chunk-based video format. If every chunk comes from a different server, the congestion cannot be accurately measured. In fact, DASH cannot implement a consistent behavior when multiple paths are used to retrieve the video chunks.

By the way, DASH is yet another point in favor of HTTP, which is becoming the de facto narrow waist of the Internet. The motivations for using HTTP include its capacity to traverse firewalls and NATs, its nice human-readable names and its capacity to leverage on Internet proxies and CDNs. Somehow, DASH adds congestion control and adaptive content, making the HTTP protocol even more powerful. But the gap between its huge utilization over the Internet and the lack of understanding of its behavior at large scale has the potential to scare network operators. I guess it is the way Internet has always evolved.

What's up in networks (2/3): hetnet

2011-11-02T17:01:00.001+01:00

Here is the second chapter of the mini-series about some (not-so-fresh) topics in networking area. After openFlow, hetnet.

Hetnet, or the Heterogeneous Cellular Networks:

I am probably not the only one to get bored by GSM cellular networks: they have been created by phone engineers who disliked Internet, they are full of acronyms, they are controlled by an operator, they just works. But cellular networks are now the most common way to access to the Internet. Moreover the devices using these networks are full-featured computers, which are managed by owners who install a lot of applications. The number of devices connected to cellular networks is expected to grow dramatically.

Next-generation cellular networks have good chances to differ from our plain old GSM networks. Here are two technologies that may change the game:

femto base stations are small and cheap base stations that anybody can buy and install on its own wired Internet connection (for example here). It means that the clients of a wireless service provider pay (base stations + landline Internet communication + consumed electric power) to improve the infrastructure of the carrier and to have an excellent quality of service at home. Carriers are all jumping into this idea. I still don't understand why would a user prefer to buy a base station and connect to Internet through the 4G although she can use wifi. The main argument is that, wifi wireless spectrum being free and badly managed, a local network can have poor performances because too many wifi access points compete or because too many devices share the pool of wireless channels. The 4G spectrum is licensed and managed by the operator, so some wireless channels can be "reserved" to a user. But if everybody has its own femtocell at home, licensed channels will become scarce too, and nobody will tolerate paying for a femtocell that interfere with the neighbors' ones. In order to tackle this issue, nearby femto base-stations should collaborate to share the wireless spectrum and react to changes in the radio environment (especially when neighbors decide to turn on/off their femto base stations). All scientists interested in peer-to-peer and ad-hoc networks will have fun with the problem of channel allocation: end-users form the infrastructure, ensuring a fair sharing of scarce resources is a challenging objective, clever distributed algorithms should solve the problem, incentives to turn on/off the femtocells should be taken into account. As shown in this article, both deployment and management of femto hetnets are still unclear. Those who are not afraid of acronym orgies can look at these slides for a summary of 3GPP standard and a nice telco-oriented overview of the research problems.
direct device-to-device wifi communication is a long-awaited feature. Hurrah, WiFi Direct, which is the official name of this feature in the WiFi alliance, is included in the new Android OS version. At least, wifi direct transmission between devices is becoming a reality, which means that the thousands of academic papers about mesh networks and hybrid ad-hoc cellular networks are suddenly worth reading. However, things have changed. Extending the coverage area of base stations, which has been the most frequent motivation in previous works related to mesh networks, is no longer the main concern of mobile carriers. It is now all about mobile data offloading, that is, avoiding communication via the macro base station. In this context, network operators may combine wifi direct and data caching in devices to reduce the amount of requests sent to the Internet. In other words, strategies related to information-centric networks may turn out to be useful in the wireless world.

In a broader perspective, the over-utilization of wireless networks for accessing the Internet highlights an interesting paradox: the wireless transmission is inherently broadcasting (all devices near the wireless router may hear all messages) although the Internet applications are usually designed for unicast communication (a message has only one destination). The capacity of a mobile carrier to leverage on the broadcasting feature of base stations in their cellular networks may become a key asset.

What's up in networks (1/3): openflow

2011-10-31T03:19:00.001+01:00

I found time to go a bit deeper into several (not-that-fresh) topics. I hope this quick summary will be of interest for those who did not. First of this mini-series: OpenFlow

OpenFlow, or the Software-Defined Networks:
Thanks to OpenFlow, I now understand the "control plane vs. data plane" idea, which I thought were mysterious magic words allowing telco engineers to recognize themselves. In the OpenFlow world, there are some dumb switches that route packets according to a routing table, and there is a clever controller, which orchestrates these switches. Switch-Controller communication uses the OpenFlow protocol.

The first novelty is that the OpenFlow protocol has been designed at Stanford, therefore (i) it is cool, (ii) software engineers have heard about it, and (iii) it is endorsed by a buzz concept, namely software-defined networking. The second novelty, but a noteworthy one, is that the main network equipment vendors integrate OpenFlow API in their switches (at least Juniper and Cisco). So, it is becoming real: software developers will really be able to control a network remotely.

OpenFlow is both networks and software:

In the network area, there is only one truth: every new concept is something already done twenty years ago. Good news for OpenFlow: it looks like MPLS. Therefore OpenFlow is a networking concept. \qed
Computer scientists are driven by vaporous concepts like model abstraction, composition and semantic. Guess what? OpenFlow designers dangerously embrace them. Even worse, network scientists have started publishing in POPL and ICFP.

More seriously, OpenFlow meets a demand. More and more "independent" networks have specific needs that cannot been addressed by router vendors. For example the network in a data-center. Private enterprise networks and even next-generation home networks are also complex networks, which would work better if they could be managed according to the wishes of their owner. OpenFlow provides the friendly interface that allow anybody (should (s)he knows programming) to become the network operator for any such network. Needless to say, this perspective brings a lot of excitements and uncertainties (see for example here and here).

Was P2P live streaming an academic bubble?

2011-10-21T05:40:00.000+02:00

Or is the academic community just disconnected from the reality?

In brief, the motivation for peer-to-peer live streaming is that servers are unable to deliver a live video at large-scale. I know, it sounds crazy in a You-Tube world. In peer-to-peer system, clients should help the poor video provider broadcast its video, without much delay nor quality degradation. To have more fun, no server at all is authorized.

Believe it or not, but Google finds more than 50,000 scientific documents dealing with this issue or one of its variants. Today, only a handful of systems based on a peer-to-peer architecture are used, mostly to illegally broadcast sport events. As far as I know, these systems (released before the crazy scientific boom on the topic) do not implement one thousandth of the scientific proposals described in these 50,000 articles. It seems that the small teams of developers behind these programs haven't found the time to download/read/understand any of these articles.

Was this abundant scientific production useless? Probably not. First, scientists made some practical achievements. For example, the P2P-Next project has released under L-GPL tons of codes implementing state-of-the-art solutions, including the multiparty swift protocol. A protocol is also in the standardization process at IETF. Consequently, the next generation of peer-to-peer programs should be able to cut down TV media industry as it did for music industry. Second, these studies have produced interesting scientific results beyond the P2P streaming applications, for example the robustness of randomized processes for broadcasting data flows in networks. It reminds me the golden era of ad-hoc networks (2000-2005), where scientists had a lot of funs playing with graphs and information, even if only militaries have found these protocol useful. We do understand networks better now!

But, did it deserve 50,000 articles? Of course not. Under-the-spotlights start-ups (Joost) and publicly-funded pioneering companies (BBC) switched back to centralized architecture four years ago although they had a decisive technological advance. It looks like there is no bankable application out there. Maybe it was for the beauty of science, but whoever has funded these research works can only hope that randomized processes in networks will eventually find a way to improve human conditions in the world. Or maybe it was just a good idea to occupy people?

So, yes, P2P live streaming was a bubble. Here are three quick observations, which would deserve a more accurate analysis:

An academic bubble starts like a financial bubble. In the latter, no company can take the risk to not invest in an area if all competitors do. In an academic bubble, neither funding agency nor program committee can challenge an abrupt growth in the number of papers in a given area. Therefore scientists obtain quick fundings, publications, and citations, which fuel the bubble. However the academic bubble differs from the financial one because there is no critical damage when the number of papers abruptly drops. The bubble does not hurt when it explodes. So, nobody tries to understand what went wrong. In other words, this bubbling trend can only grow, and the next bubble (content-centric networking?) has good chances to be even bigger.
Tracking the next bubble is attractive. Scientists are rewarded on their impact on the community. In this context, the authors of seminal works in this area, for example Chord (nearly 9,000 citations despite distributed hash table has found few usefulness) or SplitStream (more than 1,000 citations for a system relying on a video encoding that has only been used by academics), are rock-stars. Anticipating the sheepish behavior of scientists has become a key academic skill.
Scientists are still incapable to focus their energy toward their right client, who were the aforementioned small teams of hackers in this case. This is yet another motivation for revamping the way scientific results are delivered in computer science. Giving free access to papers, releasing the code that has been used in the paper, participating in non-academic events or finding echoes in other communities are among the solutions. Not only to be meaningful, but also to prevent bubbles.

Just an idea: when the bubble is officially there, would it be possible to officially forbid the bullshit motivation paragraphs in the paper? I wish authors would admit that they just want to have fun developing a new model in a useless bubbling scenario.

A warm feedback from Sigcomm

2011-08-21T02:24:00.003+02:00

The SIGCOMM conference just finished two days ago. Papers, slides, and the video of the talks are online for free. As could be expected, there is no comparison to my experience at ICC. Despite video recording prevented presenters to move on the stage, the talks were excellent: long enough, well prepared, and in a perfect english. For every talk, many questions immediately raised and people actually debate during the coffee break and social events. In brief, Sigcomm is a conference that is worth the price (registration and travel). A series of remarks below:

a Sigcomm paper should present "novel results firmly substantiated by experimentation, simulation or analysis." My understanding is that "substantiating ideas" now prevails, and that the novelty has become debatable. Some ideas, which are remarkably substantiated, do not open enough perspectives. For example, deploying wireless antenna on top of data-center racks is a cool idea, but I would not include it in my list of major scientific breakthroughs. Sigcomm program committees are expected to prefer papers that are "exciting but flawed" to the "correct but boring" ones, yet exciting is not always synonyms of inspiring. In this vein, the program includes three papers related to bit-torrent. Come on, we are in 2011! How many scientists are still interested in such an overwhelmingly addressed research area?
Europe is back, with six papers. I already mentioned that EU-funded FP7 STREP projects match the characteristics of a competitive Sigcomm paper. This year's program demonstrate the benefits of writing Sigcomm-compatible FP7 project deliverables as all accepted European papers are (sometimes partially) funded by FP7 framework. Such fundings give the opportunity to evaluate a well-identified idea though large-scale deployment. The twenty-six other papers come from prestigious american institutions, which are probably the only places that combine a unique skill in the Art of Writing academic papers and the capacity to substantiate any idea with a bunch of outstanding experimentations.
I am not really into measurements, and I will undoubtedly not be. That's probably why I struggle to identify the scientific point behind the six papers that deal with measurement in the program. Indeed, it seems that the main contribution is the result of the measure, not the way these measures have been obtained. They do not present a novel super-approach to make a brand new measurement set. Rather, the idea is that these measures provide key insights of the behavior of a particular application. I agree, but does it deserve a 14-pages LaTeX-written paper? Measurement papers would probably better fit with an infographics (like this one), wouldn't they?
I enjoyed some presentations, especially the controversial model that explains the evolution of protocol adoptions, the scheduling of network flows in data-centers, the synchronization of multiple distant data-centers, and the reduction of redundant data transfer.

Leveraging on collaborative projects to produce better academic research

2011-07-08T16:35:00.024+02:00

Opposing industrial and academic research worlds is a classic discussion. Academics have recently been suspected to address unmotivated problems because they do not manipulate the technologies that are at the core of their research activities. The importance of having an "industrial motivation" behind an academic research is reflected by a statistic: papers authored by at least one industrial researcher represent approximately half of accepted papers in the best conferences in operating systems (15 out of 32 for OSDI'11) and networking (16 out of 32 for Sigcomm'11). These papers monopolize the technical sessions related to new trends, especially datacenter and production network for OSDI, cloud computing and user measurement for Sigcomm.

In these applied science areas, the best conferences accept papers addressing industry-relevant problems if and only if (i) authors demonstrate the timeliness and relevance of the problem, and (ii) authors carefully evaluate their proposed solutions.

problem motivation: a scientist who is only reading papers about a technology can hardly formulate a relevant important problem related to this technology. In order to have an accurate view of the problems faced by companies, a first idea is to spend time there as a visiting researcher, as it is promoted in Google. Another idea is to work with industrials in projects like FP7 STREP project. I mean, actually work together, and not pretend working together.
solution evaluation: a NS2 simulation is no longer enough for a Sigcomm paper. Nowadays, some large-scale infrastructures give free access to scientists (for example Open Cirrus for a large data-center, Planet Lab for an Internet-scale network, Grid 5000 for a grid, Imagin'Lab for a 4G/LTE cellular network). There is no excuse to not test solutions over real infrastructures. However, the access to infrastructure is not sufficient, evaluations should also be based on realistic user patterns. Author of the excellent Hints and tips for Sigcomm authors claims "use realistic traffic models"! Besides using available real traces (for example the amazing network traces from Caida), the idea is again to leverage on a project collaboration with industrials that are able either to deploy a prototype on real clients, or to provide exclusive traces of their real clients.

Hence, short-term focused collaborative projects are ideal if one wants to write well-motivated well-evaluated industry-relevant papers. But, in this case, why have I never been in position to submit a competitive paper to Sigcomm although I participated in many collaborative projects? Probably because:

some of my industrial partners were not really industrial. In large companies, R&D labs are frequently disconnected from the real operational teams, so researchers in these labs are unable to provide substantiated arguments about the criticality of the project, to successfully deploy a prototype, and even to obtain traces from their real clients.
in a consortium, every partner has its own agenda. Receiving fundings while minimizing efforts may be the only point all partners agree. I rarely feel that all partners share a strong commitment to make the project actually work. More frequently, the funding acceptance is considered as the final positive outcome, the project itself being only a pain.
the project work-plan does not include the writing of a scientific paper. Scientific production is usually seen as a dissemination activity, under the responsibility of an academic partner, although writing a top-class paper requires a precise planning of the contributions of every partner (including milestones and deliverables).

Now that I understand why successful collaborative projects are critical and why my recent projects have (relatively) failed, I hope I will be able to leverage on collaboration with industrials to do better research (a.k.a. write better papers).

My (disappointing) experience of attending a large conference

2011-07-04T17:05:00.000+02:00

Last month, I attended ICC at Kyoto. ICC is the kind of large-scale academic conference, where more than 1,400 people are expected to meet and collaborate for the sake of networking science. In the meantime, several other major conferences held in the so-called Federated Conferences at San Jose, which gathered approximately the same number of researchers. Several academic scientists have already reported their enthusiasm about such big events (or raised many positive thoughts).

On my side, my experience was fairly negative. The technical and scientific discussions were rare, mostly because the conference scope is so large that the probability to chat with people sharing your scientific concerns is low. Actually, I have wondered what I was doing there during three quarters of conference time. Finally, I saw three reasons to attend big academic events:

awarding scientists: I think that scientists have been excellent students, that their commitment to excellence has again risen once they embrace an academic career, and that they are still not paid accordingly. Scientists do not receive bonuses in cash, however they frequently travel in wonderful places, with great banquet and rooms in palace. Conferencing is an award, which can be typically offered to a worthy PhD student. Similarly, professors do not hesitate to self-award with a full paid one-week conference (grants and funding allow traveling a lot, lets enjoy it). For those who like big hotels and international cities, big conferences are perfect.
meeting people from your local community: in a crowded amazingly large banquet, people first tend to cluster through languages or institutions. French chat with French, Chinese with Chinese, and members from University X with other members from University X. These "local cluster conversations" are easy to start (what plane did you take, how bad is the food in your hotel, how jetlagged are you, etc.). These local cluster conversations have at least one benefit: you have time to chat with people who you are used to meeting in local events without any chance to really discuss with. Therefore, a meeting in Japan is the place where you enhance your social network with people that live at less than 200 kilometers from your office, which is 10,000 kilometers away from Japan.
grenouilling during hallway conversations: it seems that the best translation of grenouiller is to plot. In most multi-track conferences, many people prefer to stay in the lobby and do not attend talks. They are not wrong, because many scientific talks are actually bad, and I don't think that a series of talks is the best way to foster scientific conversations. However I am afraid that conversations in the lobby are not worth a trip of thousands of kilometers neither. A large part of conversations I heard or participated was related to research administration: what will be the next event-to-attend, am I in the Program Committee of next big event, what are the latest news about the next national funding call, where could my post-doc find a decent position, if I invite you in my steering committee, would you include me in your steering committee, what are the latest transfers in the academic world, etc.

Probably because I expected some scientific enlightenments from meeting so many smart people, I have been disappointed. In particular, I definitely disagree with the scientists who argue for more maxi conferences. Next month, I will attend Sigcomm, which is a single-track reasonably-crowded (500 people) conference. Lets see if middle-size conferences are worth degrading my carbon footprint.

On the attractiveness of research institutions

2011-04-28T11:36:00.000+02:00

The job market for research tenured position is changing. First, as emphasized in a recent Nature issue, the number of graduating PhD is exploding. However the overall number of accepted papers in top-ranked conference is still desperately low. Hence, the vast majority of graduated PhD have a few minor publications and a h-index below 5. These young ambitious researchers are in the long tail of the scientists. Second, as illustrated by the closing of Intel Labs, the number of scientific jobs in private companies is dangerously decreasing. It seems that the future of research in private companies is about maintaining partnerships with universities and about outsourcing scientific studies to the right experts. In the meantime, the number of job openings in academic institutions is relatively stable. Third, academic institutions now hire scientists from all over the world. One of the consequences of the Shanghai ranking is that institutions do no longer focus on native candidates, and that many scientists look for jobs out of their native country.

Please forget the most prestigious universities and the best young scientists. Both know how to match each other. Let's rather observe the second league: the thousands of more or less famous ambitious institutions, which want to attract the best scientists, and the thousands of more or less unknown ambitious scientists who want to join the best institutions. We are in a typical assignment problem, where institutions and scientists of similar ranking should agree.

Many indicators have been proposed for the comparison of scientists. As well, many indicators or classification exist for ranking institutions for under-graduating students. But, I don't know how to measure the attractiveness of an academic institution for candidates to a tenure-track position.

Of course, three criteria prevail:

the salary. The romantic vision of the scientist who does not care of money is wrong. Scientists are humans living in a capitalist world.
the location. It includes weather, probability that the family members can enjoy (employment, schools, etc.), cultural life, and so on.
the prestige of the institution. A scientist builds a career, her resume should maximize the number of famous entries and minimize unknown ones.

Now, some more specific criteria include:

the number of free PhD students. Here, free means that the scientist does not have to produce any effort to have the guarantee that this number of PhD students will be under her advices in her lab.
the volume of teaching. It should not be too high because teaching must have no impact at all on the paper productivity. But it should not be too low because teaching is also a way to meet future PhD students.
the quality of students. Every scientist knows that bad students can be a significant waste of time, although great students can boost the productivity without much efforts.

I am quite suspicious about the importance of having top-class colleagues within the same area. Ambitious scientists have their own research area, and a majority of them have their own agenda, without regards to other scientists. This thought leads me to another criteria:

the autonomy. From a scientific point of view, a researcher prefers to define her own research axis, and to write her own research proposals, without having to justify anything. From a more practical point of view, a researcher is likely to receive grants for her research, but this money goes first through her institution, which can constraint the expenses. Consequently, a scientist might be not free to buy her own equipment, not free to travel as she wishes, not free to set the salary of a post-doc, ...

Is there any other criteria? Of course, every researcher can introduce her own weight on this criteria, depending on her personal priority.

It is now easy to analyze institutions. Typically, my current employer, Telecom Bretagne (member of Institut Telecom) :

Salary	7	Good salary when you join, low increasing though
Location	4	France is great, I do recommend Brest for a family with kids, but it is actually considered as a sub-attractive place in France
Prestige	3	I am afraid that recent branding operations have significantly affected the reputation of the institution, nobody knows Institut Telecom
Nb of free PhD students	4	No free PhD student at all, but it is not hard to obtain funding for one PhD student from the institution
Volume teaching	7	It is highly negotiable with your colleagues, you can be involved in research-oriented project management rather than formal time-wasted courses
Student quality	8	Very good engineering students, however very few are interested with research
Autonomy	8	You are definitely free to do what you want, you are almost free to manage your own budget (personal, travel, equipment)
Total	41/70

And Orange Labs, Issy-les-Moulineaux

Salary	8	Good salary when you join, good opportunities to increase
Location	9	Paris is one of the most attractive cities in the world
Prestige	5	France Telecom was a strong actor of the research, Orange is a well-known brand, but the research center is no longer a key academic player
Nb of free PhD students	2	No free PhD student at all, very hard to obtain it without significant efforts
Volume teaching	5	No teaching at all, but not difficult to find some courses in nearby universities
Student quality	4	No contact with students, but some students (not the best, though) might be interested with research internships
Autonomy	2	Not free at all. You have to justify your research axis, and, worse, you have to justify any expense, even for funded projects
Total	35/70

Now, we should create a website in order to gather ratings from several scientists, a kind of tripadvisor for scientific institutions.

inside the FP7 evaluation (last part): how to build funded proposals

2011-04-20T00:50:00.002+02:00

Don't expect any miracle from this post, and don't expect anything for posts with similar titles: there is no unique recipe for winning proposal. However, I can sketch a few tips that I will at least try to apply to my own proposals:

In the specific case of the FP7 STREP, every proposal is read by only three reviewers (no more no less) randomly picked among a set of very diverse reviewers, from experienced academics to young industrials (and vice versa) from various countries. Contrarily to the funding process of Google, there is no single reviewer target. Therefore, proposals should cover several "reading styles". Hopefully, there is no page limit, so don't hesitate to explain things several times in several ways.
The Criteria 1 ("Scientific and Technical Quality") can kill a proposal, but it can hardly make a winner. Your objective is to not give any opportunity for reviewer to criticize, so don't waste your energy there, just do a clean job. Recall that STREP is not about new scientific breakthrough, it is about incremental but sure progresses beyond State-of-the-Art. No reviewer can argue against a series of incremental loosely-consistent progresses in several domains. A bad note in Criteria 1 is more often due to a faulty or unconvincing workplan. Don't try to produce super-clever ambitious workplan, but describe things (scientific ideas and, more important, processes) that have 100% chances to be implemented. Revise your workplan a lot because some reviewers harshly track inconsistencies.
You have to differentiate, and the best place is Criteria 3 ("Exploitation and Dissemination"). The majority of proposals do not provide any market analysis, only claim standard dissemination plans, and describe very vague exploitation plans. The best proposals include real-world experimentations during the projects (which is actually appreciated), contain some partners that are actually involved in standardization processes, or have already identified some third-party companies to include in the proposal as external partners (or in a associated committee). The exploitation plan should be preferentially written at the beginning of the project, because it has a direct impact on the partners in the consortium, on the perimeter of the required scientific progresses and on the workplan (e.g. a real-world experimentation requires a specific work-package and a early prototype from technical work-packages). When the exploitation plan is strong, the whole project is fully consistent.

I know that the usual process is definitely not this one. We usually work a lot on the scientific breakthroughs, trying to copy-paste endless bibliographic works written by students, to incorporate old scientific friends and to make the whole stuff as consistent as possible. Then, we let every partner write its own work package, and we argue a lot about the number of men/months and fundings. Finally, we have a few hours to write some crappy paragraphs about the exploitation. And we have wasted at least one month because the resulting proposal is all but a winner...

Inside the FP7 evaluation (part 2): the process

2011-03-14T11:56:00.006+01:00

The European Commission and committees of major academic conferences face a same challenge: select in a fair manner a dozen of proposals out of 100 (including 90 serious candidates). The process consists of three stages:

reviewing the proposals. As I explained in my previous post, each proposal is a 100-pages long document, which is written by "artists". Three criteria are evaluated: one about the scientific soundness, one about the consortium quality and one about the exploitation. Every criteria is evaluated on a scale ranging from 0 to 5 where half-marks are accepted.
reaching a consensus. For each proposal, five people (the three reviewers, one recorder and a moderator) meet during one hour. The goal is to reach a consensus, which should result in a unified text and a final score for every criteria. The role of the recorder is crucial. She has not read the proposal, but she looked at the reviews, so she knows the main trends. From the meeting discussion, she tries to extract some statements, then her text is revised "live" by the reviewers (and sometimes by the moderator). Wording is considered as important, so some sentences require up to 15 minutes to be accepted by every reviewer. In general, meetings are lively because some reviewers disagree, and it is common that reviewers actually argue. A consensus is reached in most meetings, but frequently in a unpleasant way because an enthusiastic reviewer has few chances to convince both other reviewers, and a positive-but-not-that-much consensus does not produce a winning project. In case of unreachable consensus, additional reviewers are invited to read the proposal. Eventually, a score is voted.
deciding. The panel committee meeting is like a program committee meeting except that a ranking is produced (even rejected proposals are ranked). The overall note ranges from 0 to 15, but of course, most proposals are between 8.5 and 13.5. There is a critical tie on a high score (around 13) because only a fraction of proposals having this score can be funded. A specific algorithm is used to break ties. In our case, proposals are ranked based on:
1. the highest score in the Exploitation criteria, then, if tie again,
2. the highest score in the Scientific criteria
3. the largest ratio of industries
4. the largest ratio of SMEs
5. the largest ratio of partners from new member states of EU
The role of the reviewers is actually marginal during this meeting: checking the consistency between final texts and final score for every proposal. Downgrading (or upgrading) a proposal after a quick cross-reading is very rare, and deserves a long agreement discussion from the panel.

The overall process suffers from a drawback: reviewers spend a lot of time on bad proposals. Every proposal, even the worst one, requires one hour of consensus meeting. Saving this time could let reviewers read a subset of the best proposals, and increase the quality of the final choice. In the panel meeting, a long time is also wasted on revising the text for every proposal, even the ones that will not be funded, although panelists do not have sufficient time to discuss the borderline proposals.

The consensus part is funny. The overall result of the consensus meetings is rarely a "blind union" of three independent reviews (as it is done in most conferences, like averaging three scores). For example, three reviewers adopted a 4.0 for the scientific part (which is a very good score) but they reached a consensus with a score of 2.5 (which is below the threshold) because the flaws they identified were complementary, or because they discovered that they share an overall lack of excitement about the proposal, so they took time to detect actual flaws justifying the reject.

The overall process is fair, and there is no way to express any subjective opinion, like this topic is funnier than the other, or these guys should be assisted because their country bankrupts, or I don't like this crappy acronym.

inside the FP7 evaluation (part 1?)

2011-03-01T00:05:00.002+01:00

I am involved in the process of project evaluation for the European Commission for the first time. Some selected remarks:

there is an art of writing proposals. Scientists know that the art of writing academic papers has become a key skill in the modern science battlefield. The art of writing proposal is also widely admitted, but I had never faced it. Now I know. The top proposals I reviewed have a lot in common, including the approach and the style. Generally, these projects are about an exciting but obscured concept (vaporware?), supported by a very standard research from high-h-ranked scientists (business as usual), in cooperation with fresh SMEs (old students), and the classic large company (whose role is... hmm, well, to be there). These proposals have probably been powerpoint in a previous life: objectives are presented in a bullet-mode emphatic way, the proposal is un-verbose (so less risk of inconsistency), every page contains a figure or a table. As can be expected, the workpackage organization is perfect with an ideal balance of man-month by workpackage and by partners. It is difficult to know the future of such project. The academic work is probably already under submission. Several web revolutions will occur until the end of the project. The final software will probably fail, because it will be coded by un-managed students in University. However, in the evaluation form of European Commission, such a proposal deserves a "check" for every critical parameter, so at the end, they have good chances to win.
it is innovation, it is not about research. For those who had doubts. The best proposals are ambitious. Most of them include some attractive real-world experimentations, which requires committing a lot of developers. As the overall funding is constrained, the research-oriented demand is minimal. Moreover, as previously said, no inconsistency is tolerable, therefore every dozen of claimed man-month should be justified, and related with the remaining of the project, which is very short-term. Therefore, the scientific topic of every participating "researcher" is approximately defined in advance. Is it research? Of course not, it is the so-called innovation by research. I tend to be in favor of such early development project, however the other funding agencies (local area and national) follow the same objective, so is there a way to make un-purposed research? And why the hell are there so few innovations by research from Europe although it is already the seventh similar program?
the reviewing process is very short, but well paid. I detected one bad consequence from being a paid reviewer: reviewers have incentives to evaluate more projects, although they have no time to evaluate them carefully. Delays are very tight: I had seven projects to review in less than twelve days, each project being a hundred pages document, which details a three years long study by a consortium ranging from six to twelve partners. Moreover, the quality of the proposals was excellent, even for the worst one. Hence, one half day for a complete reviewing is minimum for a (slow?) young scientist like me. The risk is to produce a quick evaluation based on the strategy of "killing a project for any small detail". My personal reviewing strategy (I saw several people doing the same) was to first have a very quick first pass on the whole document, then to go into details once the overall concept was clear. In this context, no inconsistency is tolerable, it is better to have only one proposal writer, preferentially someone who... now come back to the first point of this post.

I will probably have more to say after my week at Brussels for the final decision.

Computer science and engineers: the (bad) French exception

2011-01-23T23:41:00.005+01:00

French engineers are famous in all domains but computer science. This is especially a shame in the 21st century, isn't it?

French engineers come from Grandes Ecoles, a French selective scholarship from undergraduate to graduating diploma. Unfortunately, many reasons explain that grandes écoles are unable to produce good engineers in computer science. Among others,

students do not know anything about computer science when they join a grande école. Neither programming, nor algorithmic... neither logic, nor graph theory... How can you learn a scientific domain from scratch in only three years? You cannot teach English literature to people who don't know English in the first place.
most grande écoles are generalists. The broad extent of the French engineering culture is an advantage, but also a major drawback in the case of computer science. Actually, teachers have just the time to either overview fundamentals, or to look at the first steps in software development, which corresponds to what billions of developers know.
each grande école is linked to a few successful French companies that massively hire their students. Unfortunately, in France, no successful company exist in computer science. There is neither IBM nor Microsoft out there. Actually, admittedly Orange is a leading company in Information Technology, but, from my experience working there for a while, I can claim that this company does not deal with computer science at all. Engineers involved in software at Orange just coordinate outsourced workers. Most of them would be unable to develop the quarter of what they outsource. As a matter of fact, Orange has never understood software innovations.
educational engineering system is self-fueled. Directors of grandes écoles and people in government are the same who have received this engineering learning and who have absolutely no skill in computer science. Therefore, computer science suffers from a dramatic lack of understanding. I ignore those who confound computer science with Microsoft Office, and I struggle with those who assimilate software engineering with indian outsourced low-level programming.

As a matter of fact, the prestigious grandes écoles that are the closest to computer science and software engineering (Institut Telecom (which is my current employer), Supelec, Ensimag and Enseeiht) focus on producing so-called "project managers", who are expected to drive low-level developers, and who consider software development as a dirty task. They are probably ideal people for French sub-innovative companies, which passively survive. But, as it is said here and there, they can forget working at Facebook or Google. And they will not be able to boost the rare French innovative companies, e.g. Dailymotion or XWiki.

We need more geeks. Actually. In a Internet era, this under-representation of geeks in the engineering grade severely penalizes France. A first idea would be to dramatically increase courses related with computer science and software engineering at the undergraduate level. Another idea would be to radically transform the mission of institutions like mine (Telecom Bretagne) so that computer science becomes the top priority. Finally, I wish bureaucrats at the governments (especially education and industry) were not from old-fashion grandes écoles.

Large-Scale Delivery of Time-shifted Streams

2010-11-14T16:40:00.000+01:00

Time-shifted streaming is a general term, which covers two main services: catch-up TV and life-streaming.

In catch-up TV, a program normally broadcast at time t can be viewed at any time after t (from a few seconds to many days). Catch-up TV is provided through network digital video recorders or personal video recorders. Catch-up TV is gaining in popularity: it accounts now for 14% of the overall TV consumption in UK households equipped with DVRs. It is also the TV usage that grew at the highest rate in 2009 in the US. However, despite the efforts of many companies, including the French SME Anevia, catch-up streaming services are still expensive to deploy because conventional disk-based VoD servers cannot massively ingest content, and keep pace with the changing viewing habits of subscribers. Moreover, clients require distinct portions of a stream so no group communication techniques such as peer-to-peer and multicast protocols can be used. Therefore, only big media actors and TV incumbents can offer these services at large scale, which is bad for innovation. Here, a peer-assisted architecture could help start-up and non-profit associations to also propose time-shifted streams to their users.

In parallel, a new form of streams is emerging: life-streams. The concept originally coined by Vannevar Bush is currently revisited by popular social network tools like twitter: every user is a producer of a life-stream, a stream of personal data that is inherently made public in order to be consumed by friends. Should life-streams joint with multimedia data generated by passive life experience capturing systems, the traffic related with these life-stream applications will become huge. In parallel, the proliferation of sensors and the rise of the Internet of things are expected to generate also a large amount of data streams. Both life-streams and sensor-generated streams require time-shifted navigation. Here, these services reveal another critical issue of time-shifted streaming systems: privacy protection. Sensitive life-streams or personal sensor-generated streams highlight the ethical limitations of any architecture having a potential point of control: lesser privacy protection, data lock-in or third-party control. We need a fully distributed system guarantying that the whole stream is actually available, including the most unpopular past portions, and that any past portion can be fetch.

Preserving the privacy of users, and lowering the infrastructure cost for innovative newcomers. Here are the two main motivations for decentralized peer-to-peer systems. It is also a topic that I want to explore further, following two recent papers: here and here. Anybody onboard?

Delivering User-Generated Content (UGC) in Massively Multiplayer Online Games (MMOG)

2010-10-08T23:19:00.000+02:00

A recent series of interviews of gamers conducted by i2media has revealed that the motivations for playing MMOG are a mix of boredom, challenge, relaxation and socializing. This result confirms the results of previous studies on the same topic. The latter point -- gaming for socializing -- has motivated the CNG project (a EU-funded project I am involved in). Indeed, the tools that enable socializing in a game without "alt-tabbing" are rare (Playxpert and Xfire). In the CNG project, we aim at developing tools that allow gamers to share User-Generated Content (UGC). The interviews have revealed that three scenarios are especially expected by players of MMOG:

a player broadcasts live screen-captured video of its game to any other player (in order to show off)
a player streams live screen-captured video of its game to a restricted group (typically a guild)
a player streams animated virtual 3D objects. The “clients” are players whose virtual position is close to the virtual position of the object.

The owner of the game is in charge of managing the "game server", which ensures the consistency of the game, and delivers the content on time. The management of the UGC is definitely not its concern. Here I come: and if the in-game UGCs are delivered in a peer-to-peer fashion? Neither cost, nor responsibility, the peer-to-peer architecture is quite attractive here.

Basically, the gamers' demand can be meet by implementing peer-to-peer live streaming systems in the game, which is a topic that has already been extensively studied. However, there are some specificities.

the diffusion of one live video stream requires that every peer receiving the video contributes with some physical resources. A peer that receives several videos will eventually reach its limits. In the scenarios 1 and 2, avoiding congestion at a peer is not difficult: it is enough to not authorizing a almost-congested peer to receive a video. For the scenario 3, the congestion management is more tricky: a player that is unfortunately too near from several UGC objects may experience congestion. Our idea is to revisit the concept of area of interest (AoI).
the game is the main motivation for the gamer, the socialization is an option. This is also true for the computing resources: the bandwidth, the CPU and the memory must always be reserved in priority to the game. In other words, the peer-to-peer video streaming system should be friendly to the other applications running on the computer of the end-users. Many classic solutions, including the ones based on Random Linear Coding, are immediately rejected because of their resource consumption. Our idea is to use rateless coding.
the live video should be delivered at about the same time for all players, especially in the scenario 3 where two players in the same region should see the same object in about the same shape. Our ideas are here still unclear.

All in all, the CNG project has good chances to be exciting. At least, it represents a good opportunity to tackle not-so-artificial challenges and to implement our solutions in real systems.

Open-source software in the Internet of Things: why we need repository-less package management system

2010-09-29T23:30:00.006+02:00

Software has become one of the most critical User-Generated Content (UGC). The number of software that are daily created or updated is overwhelming: the SourceForge community aggregates more than 2 millions of software producers, contributing on 240,000 projects software. The increasing popularity of application stores (e.g. more than 180,000 applications in the Apple Store) confirms several trends in the software industry:

crowdsourced software has become a key economical argument. Apple typically takes advantage of the number of third-party applications that are available exclusively on its devices. The capacity to offer, in a short time, the largest and most diverse amount of software and services is a challenge. In this context, most large actors of the communication industry, including phone manufacturers and network operators, propose incentives for developers (from monetary compensation to open access to data and API), which tend to reinforce the proliferation of new software.
pervasive environments need crowdsourced software. The explosion of the number of devices, as well as commercial issues (especially the time-to-market), induce a gigantic demand for software development. Actually, this demand exceeds by far the capacity of classic software producers. For example, the strength and dynamism of the Linux community is a key factor explaining the rising popularity of Linux OS for small devices.

In comparison to classic UGC aggregation, the management of user-generated software is a challenging task. Indeed, modern software often consist of a huge number of small packages. These packages have inter-dependent relationships that may easily be broken during the deployment life-cycle. Thus finding an efficient and reliable way to maintain, distribute and install these software packages over billions of machines is definitely an issue. In the current approach, software distributors rely on a set of repositories, which are centralized servers collecting all the packages that have been certified. We distinguish two major drawbacks in this architecture:

the certification of packages. The software distributor plays the role of a certification authority. Users must deposit their packages if they want them to be integrated into the repositories. The distributor verifies the integrity of the submitted packages and makes the valid ones available for other users to download. As addressed in the EDOS project, there exist various approaches and tools facilitating the management of large repositories of packages. However, the centralized structure requires expensive infrastructure and extra human management. The process of certificating third party packages is slow and complex. Typically, developers complain about the increasing delay for software availability in the Apple Store. Clearly, a centralized certification of packages does not scale. It is also a severe threat for the privacy of users.
the delivery of packages. It has been emphasized by Microsoft researchers that a set of repositories can not ensure a fast, planet-scale, delivery of packages. However, massive delivery of software patches is a key security requirement. If the number of devices grows as it is commonly admitted in the Internet of Things vision, the limits of a centralized repository-based architecture will soon reach its limits. Moreover, devices in pervasive environment are not necessarily always connected to the Internet. We need to also rely on intermediate devices and opportunistic ad-hoc communications if one wants to upgrade all devices, including the tiniest ones.

We need to revisit, in a clean-slate approach, the package management system: a fully distributed (repository-less) system, which presupposes a modification on the common inter-dependent relationships between packages. We propose an internship, which is expected to be a small first step in that direction.

One academic world, two divergent ways to live it

2010-09-15T23:35:00.001+02:00

The academic world is like the media industry. Some actors understand the opportunities offered by digital world, the others are still unable to revolutionize themselves in order to fit with our century.

On one hand, you have the unexpected success of a Q&A website devoted to Theoretical Computer Science. Anybody can post question, anybody can suggest answers, anybody can vote on the relevance of these answers. A reputation score is given according to the number of received votes, this reputation score allowing you to slowly become a kind of administrator. Such a website is often associated with chatting teenagers. In this case, more than one thousand of serious academic people subscribed (a third of the whole community?), and now these serious people everyday chat about problems related with theoretical computer science. The bootstrap was uneasy, but the success is here. For example, quantum computing was a hot topic today with two threads. Active participants include PhD students, unknown people, distinguished professors...

Wait, these guys who are expected to review the crappy papers I submitted to prestigious journals are wasting their time chatting with friends instead of doing their job? Well, it seems that the emerging conversation between scientists is worth spending a significant time on the website.

On the other hand, you have the editor of a journal in the network community. I reviewed a bad-but-not-so-bad paper two months ago. The editor sent me a kind email yesterday in order to inform me that, based on the different reviews (two or three reviews I suppose) the paper has been rejected. I kindly requested the other reviews. I just want to know what other scientists who read the same paper as me have thought about this paper. Were they as harsh as me? Were they annoyed by the same weaknesses as me? Did I miss important flaws? Did I misunderstand some points? I received a kind reply "Sorry we don't do that". The reviews exist, but the reviewers cannot access them because the editor has decided so. In parallel, I am in a Program Committee (PC) for a workshop. The reviewing platform does not authorize me to look at the papers that have not been assigned to me. I complaint te PC chair, but his reply was "The main task of TPC members is to give their technical opinion about the papers assigned to them. It would not be of any use if you could access the other papers, since those papers will have their own TPC members." And if I just want to do something that has no use for you, but has interest to me? And if I want to review other papers just for fun? And if I found that a paper that has not been assigned to me deals with a topic I find interesting? And if I want to contribute to the discussions about an exciting paper?...

I am not surprised that it is more and more difficult to find motivated reviewers able to write their reviews on time. What is the incentive to write a review if it is not part of a conversation? The collaborative work about the P vs NP story has demonstrated that collaborative reviewing is far better than just a sum of blind reports.

We could obviously go farther. Here is a list of small changes, ranked from the easiest to the most difficult to admit:

all TPC members access all papers,
all TPC members access all reviews,
all TPC members write reviews for any paper,
all authors access all papers,
all authors access all reviews,
all authors write reviews for any paper,

Would it be a perfect way to prepare a workshop where participants actually discuss?

Research in decentralized peer-to-peer: death and need

2010-09-06T16:30:00.000+02:00

Gnutella and Kazaa appeared at the end of the last century. The promises of these systems has fostered a intense research activity in the area of peer-to-peer networks. The two most cited papers in Computer Science between 2000 and 2010 are both related with peer-to-peer systems. At that time, the motivations that researchers were authorized to admit were the scalability, and the dependability. The design of free systems (i.e. without any central authority) has never been a convincing argument neither for reviewers, nor for funding agencies. For example, two classic papers in the literature of peer-to-peer -- bit-torrent and freenet -- have been published in minor crappy conferences.

So far, data-centers have demonstrated to be scalable and dependable. In this context, the interest for peer-to-peer systems declines. Immediately, the main conferences dealing with peer-to-peer have claimed to be open to submissions of papers being not totally distributed: it is the time of peer-assisted architectures, and overlays of devices controlled by a central authority (e.g. set-top-boxes). See for example this paragraph in the Call for Papers of the ninth workshop on Peer-to-Peer Systems (IPTPS 2010)

"This year, the workshop's charter will be expanded to include topics relating to self-organizing and self-managing distributed systems. This is in response to recent trends where self-organizing techniques proposed in early peer-to-peer systems have found their way into more managed settings such as datacenters, enterprises, and ISPs to help deal with growing scale, complexity, and heterogeneity. In the context of this year's workshop, peer-to-peer systems are defined to be large-scale distributed systems that are mostly decentralized, are self-organizing, and might or might not include resources from multiple administrative domains."

Another consequence is that the only area where peer-to-peer experts can reasonably argue that pure peer-to-peer systems make sense -- live streaming systems -- has received an dramatic attention fueled by tons of grants: more than seven thousands papers containing the words peer-to-peer, live and streaming have been published since 2009. From an algorithmic perspective, the similarities between pure peer-to-peer and Content-Centric Networking make that this latter is becoming a hot topic among the peer-to-peer experts. To my opinion, the gap between this sudden peak of scientific works and the need for research in these areas is huge.

But, what about the research about fully decentralized peer-to-peer architecture for free systems? The troubles around Wikileaks, the recurrent funding issues faced by free services like wikipedia or arXiv, and the terrible privacy problems of current social platforms should invite every reviewer (not only in conferences but also in funding agencies) to consider the "free systems" motivation as critical.

Content-Centric Networking and the Revolution of Content Delivery

2010-09-01T12:20:00.000+02:00

Many scientists in the networking field are excited by what has been initially called Content-Centric Networking. Recently, two national funding agencies have announced large projects in this area: Named Data Networking by the US NSF, and Réseaux Orientés au Contenu by the French ANR. Here is my focus on this topic.

It seems that new generations of Internet routers will have the capacity to cache content. Their future deployment represents an opportunity to revisit the techniques that are currently used in the Internet to deliver content. So far, the flaws of the Internet and the drawbacks of IP-layer multicast have been overcome by Content Delivery Networks (CDN) such as the Akamai network. In brief, a CDN is comprised of around a hundred of thousands servers, which are located as near as possible of end-users' networks. These servers are in charge of storing and delivering the content of their clients (here, some service providers) to the end users. Somehow, the predominance of CDNs is a part of the network neutrality debate, because small service providers can not have the same quality of service than Akamai-powered incumbents.

The seminal works done at the Palo Alto Research Center (PARC) addressed the fundamental issue of routing queries and data based on content name. These works enable the exploitation of the caching feature of new Caching Routers. However, the management of thousands of in-network Caching Routers is still an open question, which has to take into account:

the distributed nature of this caching system. Contrarily to the centralized management of CDN, the envisioned network of Caching Routers is by nature distributed: every Caching Routers is expected to decide by itself whether a content that it routes should be cached or not. Moreover, a claimed objective is to retain the simplicity and scalability of current Internet protocols. Actually, Internet works because it is simple, let's stick to this approach.
the complexity of the peering relationships between autonomous networks in the Internet. Internet is a loosely-coordinated aggregation of networks. The equilibrium of the whole Internet depends on the selfish actions of every network. The deployment of Caching Routers is among the few events that have the potential to significantly impact the behavior of inter-network relationships, and affect the global Internet.
the evolution of content. Cisco claims that video traffic will represent 90% of the overall Internet traffic in 2014. If video clips à-la-YouTube can be treated as a classic cacheable content object, many other forms of video services are emerging. In particular, time-shifted streaming is becoming a major trend, for TV of course, but also for potential life-streaming systems (lifecasting). As we have recently showed, these new forms of video consumption represents a challenge for network management.

These challenges are actually exciting. Yet, as usually in the networking community, scientists work in close projects, and prepare papers, which are submitted in prestigious conferences like Infocom, or NSDI, but are too rarely released in an open library like arXiv.

The emerging web-based science era

2010-08-17T23:18:00.001+02:00

I have been looking for incentives to start blogging for almost five years. I think it is the right time now. The recent events related with the (not so convincing) P vs. NP proof were the ultimate trigger, which let me think that academic science has entered into a new era.

During the summer, I had the feeling that the everlasting flow of criticisms against the flawed academic processes becomes stronger. Some scientists still try to address classic problems of peer reviewing, or to revolutionize the habits of their community. The most cynical ones emphasize that the actual reality of academic sciences is that it is all for the Art of writing papers. In this depressive context, the "P is not equal to NP" truc occurred. Here is the timeline of this event.

As mentioned in this NYTimes article, one of the greatest outcomes of this "bomb" is the spontaneous collaboration, which has emerged between scientists. In my opinion, it is not so surprising. Indeed, the community of "Theory of Computer Science" has already embraced many tools of the web. Many scientific leaders blog and tweet with high frequency. Look for instance at this aggregator. They also make efforts to put online the articles accepted at the flagship conferences.

In comparison, the communities related with Computer Science that I know are not so well organized. Typically, I observed that no scientist tweets during the PODC conference! I am also not aware of a lot of bloggers among the networking community. Therefore, when a major new idea is published, the debates are not online. Every team silently work in order to produce the most artistic paper, which will be accepted at the next must-be conference. For example, look at the (lack of) reactions to this great post from one of the very few blogging scientist in the network community.

In this context, I see my tiny blogging contribution as an experiment of new scientific collaborations beyond conferences, journals, h-index, etc. Besides, I want to be ready when my communities will switch to the new web-based science era!