There are bad news. Viruses and worms are subject to a constant evolution and we are far from reaching the steady state. New influenza viruses, an infectious disease caused by RNA viruses, are constantly produced by mutation and reassortment (the mixing of genetic material from two similar viruses). In the olden days of computing, when we gazed at EGA graphics, computer users content against boot sector viruses and other malicious code affecting their programs. These kinds of viruses became less common in later generations where virus developer focused on exploiting the rich scripting functionalities provided by modern office application suites and Macro Viruses were becoming more widespread. Nowadays, one has to cope with security exploits in hosted software (e.g. phpBB), security leaks in web 2.0 applications (e.g. Facebook applications), phising, ….

This are well-known facts. I presented them to illustrate that viruses evolve and infect new hosts. The bad news is that research has been infected by a new virus called scholastica googlensis, as Alois Potton highlights in the 3/2008 issue of the PIK journal. Scholastica googlensis causes a linearisation of humans aiming towards a perfect alignment, making researchers comparable. Reputation is reduced to a single number, the Google Scholar index, expressing the amount of papers written by the considered author which are indexed in Google’s database. Only the number counts, publish or perish! Research is scaled down to a single metric. The higher the index, the higher the reputation, the higher chances are in an appointment board when filling a vacancy for an full professor. Alois Potton mentioned in his column the idea to reduce the review process at Dagstuhl seminars to a single one dimensional number: the Google Scholar index of the author. Life can be pretty simple.

The consequences are that a single company using the page rank algorithm not only controls the available knowledge - a fact is known, if and only if it is presented within the first n search results - but also influences the way knowledge is created by impairing the selection process in research.

Regarding to Einstein, everything should be made as simple as possible, but no simpler. Is this metric already a way too simple?

I’ll give a talk entitled Statistical Error Model to Impair an H.264 Decoder tomorrow at Deutsche Telekom Laboratories / Berlin Institute of Technology. Further information can be found here.

Abstract:

Real-time Internet services are gaining in popularity due to rapid provisioning of broadband access technologies. Delivery of high Quality of Experience (QoE) is important for consumer acceptance of multimedia applications.
IP packet level errors affect QoE and the resulting quality degradations have to be taken into account in network operation. This talk shows how second order statistics of the number of packet losses in finite Markov models over several relevant time-scales can be derived and used to adapt models to the loss process visible in traffic measurements in wired and wireless networks.

Markov models obtained in this way provide a generator for packet loss pattern to be used in the estimation of the degradation in the Quality of Experience QoE) for Internet services, especially real-time video streams.

The evaluation of statistical properties of video streams impaired by Markov models generating packet loss shows shows different error pattern at the application (video) layer depending on the used parameter estimation method. This finding highlights the need for models replicating error pattern which are relevant for higher layers.

I was reading the 1/2008 (March) issue of EURESCOM mess@ge covering The Future Internet today. An article by Milon Gupta introduced the OMEGA project, which is running from 2008 to 2010 and focuses on “Gigabit speed at home without cable clutter”. The project is motivated by the fact that the home network could become the bottleneck in the future, high-speed Internet, as “many devices are limited to wireless transmission rates of 54 megabit per second, or require troublesome wiring to achieve higher rates”. The article proposes the following solution to install comfortable, high-speed home networks: “OMEGA will overcome these limitations by increasing the speed to one gigabit per second and by connecting home devices to the Internet and to each other through power line communications and wireless connections”.

Power line is a technique where, roughly speaking, data is transmitted using electric power lines instead of dedicated but more appropriate network cables. This approach is comfortable as a network of power lines is already installed in today’s homes and devices can be plugged in everywhere to get connectivity without worrying about running network cables. However, using power lines as carrier for wideband signals, such as high-speed network communiction, is a questionable approach as power lines are untwisted and unshielded and thus form a large antenna which will radiate the signals sent over power lines. Therefore, there is a high potential for interfering other radio services or being interfered. Power line communication can make HF Radio services–allowing world-wide communication and thus invaluable services such as emergency networks–unusable. Is it really worth loosing an invaluable resource just to send data using inappropriate wires? More information can be found here:

• “Broadband Over Powerline (BPL) and Amateur Radio” by the American Radio Relay League. A good article covering many details about why amateur radio is concerned about the deployment of BPL.
• “The effects of power-line telecommunications on broadcast reception” by BBC research.
• “Video and Audio recordings of BPL Interference“
• “Track and Solve Electrical Interference“
• “Wireless Institute of Australia review of Power Line Communications (PLC) / Broadband over Power Lines (BPL) in Australia” stating that “from all observations to radiate electromagnetic energy of such intensity that it will substantially interfere with not just Amateur Radio, but all HF and low VHF radiocommunications”
• BPL Flyer by the Wireless Institute of Australia
• “Power line : Potential for Interference“

Is sending wideband signals over untwisted and unshielded wires really the highest of highs in electrical engineering? Maybe research should think about alternatives without suggesting to deploy the next best but inappropriate solution?

PS: Does this highlight the need to revisit the song released by the Buggles in 1979 entitled Video Killed the Radio Star?

I’m right back from the Meeting of VDE/ITG’s Next Generation Internet section. A prototypic P2P SIP implementation has been shown. The implementation was straight forward using classical techniques such as a Bamboo DHT for storing accounting data, hybrid encrypting of the communication and using the IETF P2P SIP  location data tag for exchanging location information.

Other, highly interesting topics of this meeting were carrier Ethernet (the IEEE 802.1(Qay) protocols)  and NGOSS.

I just returned from this years International Packet Radio Conference (IPRT) which was held at Darmstadt University of Technology. The scope of the conference is digital data transmission in amateur radio in general and is not limited to packet radio using the AX.25 protocol as the name might suggest. Their were ten talks in two tracks, a bit less than last year.

In the first talk, Michael Zähringer, DB3MZ, spoke about Galileo, the global satellite navigation system build by the European Union. As amateur radio operators are operating as secondary users on a frequency range (23 cm) also used by Galileo, some interferences are expected. For transmitting the time signal to the receivers used for computing the position their position on the sphere, Galileo is using a 50 MHz wide pseudo noise carrier which is close to the noise limit and will thus not interfere narrow band amateur radio transmissions. However, amateur radio transmissions are likely to interfere Galileo navigation receivers as their Automatic Gain Control (AGC) will react to the strong amateur radio signal  and makes Galileo signals undecodeable. This effect was demonstrated in a test area in Berchtesgaden where six Galileo transmitters are installed at the surrounding mountains. During experiments with prototypic Galileo receivers, their AGC reacted to the narrow band packet radio data transmissions of nearby packet radio digipeaters operating on the 23cm band. As the speaker mentioned, Infineon reacted to this problem by limiting the AGC to broadband signals only.

As this part of DB3MZ’s talk highlighted operational problems, the last part focused on applications of the Galileo time signal. As Galileo has a more accurate phase noise than GPS, it can be used for low power, low bandwidth transmissions. The amateur radio operator W6NEY,  professor at Stanford University, with Coherent CW (CCW) using GPS which only requires 5 to 10 Hz bandwidth and thus enables efficient low power transmissions. These experiments can be continued using the Galileo signal.

A nice story in his talk was about the decryption of the code used by Galileo for encrypted signals.  This code was decrypted by hackers of the German Chaos Computer Club (CCC) and was changed by Galileo. This reminds be a bit to the cat-and-mouse game played by a German pay TV provider, who frequently change his encrypted code whenever someone cracked it. As the latter told us, people are always able to crack the encryption. Thus the question rises up, how often they are going to change it …

Thomas Kleffel, DG5NGI, presented three boards used for transmitting DVB-T/S, gPSK, ATSC, gMSK, … signals in the scope of digital TV and broadband data communication. The MiniMod board he constructed and presented can be used for narrow band DVB-S (> 1.8 Mhz bandwidth) TV signals, as currently used in northern Germany, narrow band DVB-T (> 2 Mhz bandwidth) and gMSK. The latter is a interesting mode for amateur radio operators as the requirements of the power amplifier (PA) in terms of linearity are relaxed and a normal class C PA used for analog FM signals is enough. The second board presented in his talk can be used as an Ethernet over DVB bridge for broadband data communiction (e.g. for D-Start or Echolink access). It is more expensive than using cheap WLAN hardware, but more flexible, as arbitrary frequency ranges can be used as well as linear amplifiers.

Rein Couperus, PA0R, introduced PSKmail which he has developed in the past three years. This mode is used for accessing mail and the Web (”the slowest interface to Google”) via HF on long distance. PSKmail is using PSK for modulation and data transmission along with a ARQ for re-transmission of lost frames. Unlike PSK63 which reduces its bandwidth from 2,4 kHz to 500 Hz when the signal reception decreases, PSKmail reduces its frame size by using a constant bandwidth. PA0R demonstrated how electronic mail can be downloaded from servers and accessed locally by the mail user agent (MUA) Evolution in Linux, or to access the Web (including carrying out Google queries) by wget.

Jochen Berns, DL1YBL, discussed Icom’s Digital Voice system D-Start and the experiences obtained by operating D-Star repeaters in Germany. The subsequent discussion was controversial as the vocoder used by D-Star is closed source and needs to be licensed. This limits the experimentation with a new technology and may contradict the experimental nature of amateur radio.

All in all, it was a nice event and I’m looking forward for next years IPRT, where an anniversary can be celebrated–the 25th IPRT. See you next year!