Telecom is 10 years behind wall street on time synchronization

This is an interesting paper, but Telecom has not yet come to grips with the problems and advantages of fast shared commodity ethernet interconnect.

North American service providers are in the process of upgrading their radio access networks with next generation LTE equipment. They arefinalizing a 4G rollout that involves highly stringent timing requirements, but in many cases theyare relying on sole-source synchronization byusing Global Navigation Satellite System (GNSS). Natural occurring disturbances, as well as unintentional radio frequency jamming, intentional jamming, and spoofing, make GNSS vulnerable to interference.

This article presents a novel approach for addressing the issue of GNSS vulnerability by introducing a standard means of providing a redundant packet-based synchronization source for LTE base stations. It also describes how this new approach can mitigate noise caused by asymmetry and transit delay variation in packet networks.

commag-pearson-rev2colonial-williamsburg

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Project Roseline

Accurate and reliable knowledge of time is fundamental to cyber-physical systems for sensing, control, performance, and energy efficient integration of computing and communications. This simple statement underlies the RoseLine project.  Emerging CPS [Cyber Physical Systems – vy]  applications depend on precise knowledge of time to infer location and control communication.  There is a diversity of semantics used to describe time, and quality of time varies as we move up and down the system stack.  System designs tend to overcompensate for these uncertainties and the result is systems that may be over designed, in-efficient, and fragile.  The intellectual merit derives from the new  and fundamental concept of time and the holistic measure of quality of time (QoT) that captures metrics including resolution, accuracy, and stability.  

The project will build a system stack that enables new ways for clock hardware, OS, network services, and applications to learn, maintain and exchange information about time, influence component behavior, and robustly adapt to dynamic QoT requirements, as well as to benign and adversarial changes in operating conditions.  Application areas that will benefit from Quality of Time will include: smart grad, networked and coordinated control of aerospace systems, underwater sensing, and industrial automation.  The broader impact of the proposal is due to the foundational nature of the work which builds a robust and tunable quality of time that can be applied across a broad spectrum of applications that pervade modern life. Roseline.

Why is computer science education so horrible

This is a post about CS education. It is prompted by a seriesofposts by Mark Guzdial in which he criticizes the pervasive belief among CS educators that when it comes to programming, there’s not much an instructor can do: some students get it, others don’t; it’s all in genetics or other external factors that CS educators can’t influence (aka the Geek Gene Hypothesis). I am with Mark on this, but I feel a bit stronger about it than he does. I think that attitude is bullshit, and the studies supporting it are unsound by means of making conjectures ignoring an enormous number of confounding factors.  Cristina (Crista) Videira Lopes

A lot of it is not even teaching method, it is  attitude.  When CS was “professionalized” in the 1970s, all the stupid gatekeeper ambitions and pointless competition from the traditional “hard sciences” and engineering were imported.  When I taught intro CS, I found that the most important part of my walljob was sustaining the morale of the students who came in without programming background (and many bad ideas).

Harvey Mudd, as Vidiera points out, has actually tried to address these problems and

Our instructors had private conversations with students who were using up a disproportionate amount of air time in class talking about arcane details and asked them to have those conversations with the instructors in private because other students found their level of knowledge intimidating. [US News]

Not being as nice, smart, or hardworking as the people as Harvey Mudd, I used to just tell those students to shut up and learn something in my class. And I spent a lot of time telling other students not to worry, that the “experts” didn’t actually know anything near what they thought they did. The common attitude among CS teachers, who are generally former arcane-air-time students themselves, is quite different.

JP Morgan Security Breach

“Faced with the rising threat of online crime, JPMorgan has said it plans to spend $250 million on digital security annually, but had been losing many of its security staff to other banks over the last year, with others expected to leave soon.” – New York Times. 

Why is it that NY banks can spend so much money on computing infrastructure and find themselves short of actual talent so frequently? There are very sharp people working in finance technology, but …

Paths versus Recursion

/*
 * Iterative DepthFirst file list (c) Victor Yodaiken 2013
 *
 * "Not the way we do it in Brooklyn" - Dave "Kinch" Arnow.
 *
 *
 * Data structure is P - the current path, with some aux data
 *
 * Two basic operations:
 * 1) Lp(P) - starts at path P and extends it to the leftmost
 * reachable file/directory
 * 2) IterateDF(P) iterates by advancing a path to the next in depth
 * first order
 *
 * So program is
 *
 * Initialize(P);
 * do{
 * PrintPath(P);
 * }while(IterateDF(P) != EOF)
 *
 *
 * Horribly inefficient - can be cured by caching positions in directory
 * entries.
 *
 * */
Link to Code