Problems with my DSL, Recent Down-Time

I take the unusual approach of Hosting my site and blog on my private PC at home. This is not a recommendation for other people to do the same thing, it’s just how I do it. But then a side effect of what I do is the fact, that the availability of this blog is only as good, as the (DSL) network connection of my PC at home.

In recent weeks, Quebec, the province I live in, has been pounded by extremely cold weather (below -20⁰C), as well as more than one snow-storm. And this has played havoc with many customers’ service, as ice and water can penetrate the cables.

For that reason the availability of my site and blog has also experienced many issues. I apologize to my readers if this has inconvenienced them.

For the moment it looks like my ISP has been able to stabilize my connection, by reducing the speed with which I connect, and I’m fine with that, since a stable but slower connection is preferable to no connection at all.

I’m looking forward to some better solution in the distant future, but am confident that in the short term, the connection has been made stable again.

Dirk

 

Print Friendly, PDF & Email

A Hypothetical Algorithm…

One of the ideas which I’ve written about often is, that when certain Computer Algebra Software needs to compute the root of an equation, such as of a polynomial, an exact Algebraic solution, which is also referred to as the analytical solution, or symbolic Math, may not be at hand, and that therefore, the software uses numerical approximation, in a way that never churned out the Algebraic solution in the first place. And while it might sound disappointing, often, the numerical solution is what Engineers really need.

But one subject which I haven’t analyzed in-depth before, was, how this art might work. This is a subject which some people may study in University, and I never studied that. I can see that in certain cases, an obvious pathway suggests itself. For example, if somebody knows an interval for (x), and if the polynomial function of (x), that being (y), happens to be positive at one end of the interval, and negative at the other end, then it becomes feasible to keep bisecting the interval, so that if (y) is positive at the point of bisection, its value of (x) replaces the ‘positive’ value of (x) for the interval, while if at that new point, (y) is negative, its value for (x) replaces the ‘negative’ value of (x) for the interval. This can be repeated until the interval has become smaller than some amount, by which the root is allowed to be inaccurate.

But there exist certain cases in which the path forward is not as obvious, such as what one should do, if one was given a polynomial of an even degree, that only has complex roots, yet, if these complex roots nevertheless needed to be found. Granted, in practical terms such a problem may never present itself in the lifetime of the reader. But if it does, I just had lots of idle time, and have contemplated an answer.

(Updated 1/22/2019, 9h45 … )

Continue reading A Hypothetical Algorithm…

Print Friendly, PDF & Email

A Possible Vulnerability, in our Above-Ground Telephone Cables

When I was a young teenager, I sometimes spoke to tech professionals, who were working on power-lines and/or telephone cables, the latter of which were strung above-ground from the usual telephone poles. Sometimes, those tech professionals were disposed to answer my curious questions.

What above-ground telephone cables had or have, is refrigeration stations at some of their connection-points, that refrigerate air to “-20⁰C”, which also makes the air very dry, and then to feed that air into the cables in compressed form. The purpose of this exercise is to prevent moisture buildup inside the telephone cables, that have hundreds of wires, if not thousands of wires.

Assuming that such a unit is being used, the question remains unanswered of how it’s supposed to work, if the outside air temperature is below -20⁰C. If the process continues, then air will be fed into the cables at a higher temperature than the ambient temperature, at which point technically, the air being fed in is also moister, than the saturation point of the ambient air. (:1) What could follow, is ice build-up in the cables, and, when the temperature outside rises suddenly, the ice can melt.

I’m not sure what the exact conductivities are, but think that liquid water conducts better than ice, so that liquid water can cause shorting of the telephone wires inside the cables. I suppose that if the ambient air stays warm long enough, continued feeding of cold, dry air into the cables can dry out the cables again…

(Updated 1/20/2019, 7h40 … )

Continue reading A Possible Vulnerability, in our Above-Ground Telephone Cables

Print Friendly, PDF & Email

My Experiences with the Bell Home Hub 3000

My ISP is Bell Canada, and my LAN connects to a service of theirs called ‘Fibe 50′, which stands for a 50 Mbps, DSL connection, to a Local Node, which in turn is connected to Bell via Fibre Optics. And this connection of my LAN is accomplished through a Home Hub 3000 Modem / Router.

The fact that I use my home PC as my Web-server, also means that a stable Internet connection is especially important to me, even though officially, I’m just a Home User. Just recently, my site experienced some down-time, due to problems with my DSL. And I’d like to weigh in on how good or bad the Home Hub 3000 might be, based on personal experiences.

First off, this Modem / Router once had a very bad reputation, when it was first released for public use, in the year 2016. But because that release of the modem preceded my personal range of experiences, I’m going to ignore this piece of History for the moment. It could very well be that in the year 2016 the modem was not ready to be released yet, but that in the year 2019, it is. This would be one example, where the service provider did their best to patch the behaviour of the modem, with many firmware updates, but without any actual modifications to the circuitry being possible.

Continue reading My Experiences with the Bell Home Hub 3000

Print Friendly, PDF & Email