My Data Kraken – a Shapeshifter

I wonder if Data Kraken is only used by German speakers who translate our hackneyed Datenkrake – is it a word like eigenvector?

Anyway, I need this animal metaphor, despite this post is not about facebook or Google. It’s about my personal Data Kraken – which is a true shapeshifter like all octopuses are:

(… because they are spineless, but I don’t want to over-interpret the metaphor…)

Data Kraken’s shapeability is a blessing, given ongoing challenges:

When the Chief Engineer is fighting with other intimidating life-forms in our habitat, he focuses on survival first and foremost … and sometimes he forgets to inform the Chief Science Officer about fundamental changes to our landscape of sensors. Then Data Kraken has to be trained again to learn how to detect if the heat pump is on or off in a specific timeslot. Use the signal sent from control to the heat pump? Or to the brine pump? Or better use brine flow and temperature difference?

It might seem like a dull and tedious exercise to calculate ‘averages’ and other performance indicators that require only very simple arithmetics. But with the exception of room or ambient temperature most of the ‘averages’ just make sense if some condition is met, like: The heating water inlet temperature should only be calculated when the heating circuit pump is on. But the temperature of the cold water, when the same floor loops are used for cooling in summer, should not be included in this average of ‘heating water temperature’. Above all, false sensor readings, like 0, NULL or any value (like 999) a vendor chooses to indicate as an error, have to be excluded. And sometimes I rediscover eternal truths like the ratio of averages not being equal to the average of ratios.

The Chief Engineer is tinkering with new sensors all the time: In parallel to using the old & robust analog sensor for measuring the water level in the tank…

Level sensor: The old way

… a multitude of level sensors was evaluated …

Level sensors: The precursors

… until finally Mr. Bubble won the casting …


… and the surface level is now measured via the pressure increasing linearly with depth. For the Big Data Department this means to add some new fields to the Kraken database, calculate new averages … and to smoothly transition from the volume of ice calculated from ruler readings to the new values.

Change is the only constant in the universe, paraphrasing Heraclitus [*]. Sensors morph in purpose: The heating circuit, formerly known (to the control unit) as the radiator circuit became a new wall heating circuit, and the radiator circuit was virtually reborn as a new circuit.

I am also guilty of adding new tentacles all the time, too, herding a zoo of meters added in 2015, each of them adding a new log file, containing data taken at different points of time in different intervals. This year I let Kraken put tentacles into the heat pump:

Data Kraken: Tentacles in the heat pump!

But the most challenging data source to integrate is the most unassuming source of logging data: The small list of the data that The Chief Engineer had recorded manually until recently (until the advent of Miss Pi CAN Sniffer and Mr Bubble). Reason: He had refused to take data at exactly 00:00:00 every single day, so learned things I never wanted to know about SQL programming languages to deal with the odd time intervals.

To be fair, the Chief Engineer has been dedicated at data recording! He never shunned true challenges, like a legendary white-out in our garden, at the time when measuring ground temperatures was not automated yet:

The challenge

White Out

Long-term readers of this blog know that ‘elkement’ stands for a combination of nerd and luddite, so I try to merge a dinosaur scripting approach with real-world global AI Data Krakens’ wildest dream: I wrote scripts that create scripts that create scripts [[[…]]] that were based on a small proto-Kraken – a nice-to-use documentation database containing the history of sensors and calculations.

The mutated Kraken is able to eat all kinds of log files, including clients’ ones, and above all, it can be cloned easily.

I’ve added all the images and anecdotes to justify why an unpretentious user interface like the following is my true Christmas present to myself – ‘easily clickable’ calculated performance data for days, months, years, and heating seasons.

Data Kraken: UI

… and diagrams that can be changed automatically, by selecting interesting parameters and time frames:

Excel for visualization of measurement data

The major overhaul of Data Kraken turned out to be prescient as a seemingly innocuous firmware upgrade just changed not only log file naming conventions and publication scheduled but also shuffled all the fields in log files. My Data Kraken has to be capable to rebuild the SQL database from scratch, based on a documentation of those ever changing fields and the raw log files.


[*] It was hard to find the true original quote for that, as the internet is cluttered with change management coaches using that quote, and Heraclitus speaks to us only through secondary sources. But anyway, what this philosophy website says about Heraclitus applies very well to my Data Kraken:

The exact interpretation of these doctrines is controversial, as is the inference often drawn from this theory that in the world as Heraclitus conceives it contradictory propositions must be true.

In my world, I also need to deal with intriguing ambiguity!

Learning General Relativity

Math blogger Joseph Nebus does another A – Z series of posts, explaining technical terms in mathematics. He asked readers for their favorite pick of things to be covered in this series, and I came up with General Covariance. Which he laid out in this post – in his signature style, using neither equations nor pop-science images like deformed rubber mattresses – but ‘just words’. As so often, he manages to explain things really well!

Actually, I asked for that term as I am in the middle of yet another physics (re-)learning project – in the spirit of my ventures into QFT a while back.

Since a while I have now tried (on this blog) to cover only the physics related to something I have both education in and hands-on experience with. Re General Relativity I have neither: My PhD was in applied condensed-matter physics – lasers, superconductors, optics – and this article by physicist Chad Orzel about What Math Do You Need For Physics? covers well what sort of math you need in that case. Quote:

I moved into the lab, and was concerned more with technical details of vacuum pumps and lasers and electronic circuits and computer data acquisition and analysis.

So I cannot find the remotest way to justify why I would need General Relativity on a daily basis – insider jokes about very peculiarly torus-shaped underground water/ice tanks for heat pumps aside.

My motivation is what I described in this post of mine: Math-heavy physics is – for me, that means a statistical sample of 1 – the best way of brazing myself for any type of tech / IT / engineering work. This positive effect is not even directly related to math/physics aspects of that work.

But I also noticed ‘on the internet’ that there is a community of science and math enthusiasts, who indulge in self-studying theoretical physics seriously as a hobby. Often these are physics majors who ended up in very different industry sectors or in management / ‘non-tech’ jobs and who want to reconnect with what they once learned.

For those fellow learners I’d like to publish links to my favorite learning resources.

There seem to be two ways to start a course or book on GR, and sometimes authors toggle between both modes. You can start from the ‘tangible’ physics of our flat space (spacetime) plus special relativity and then gradually ‘add a bit of curvature’ and related concepts. In this way the introduction sounds familiar, and less daunting. Or you could try to introduce the mathematical concepts at a most rigorous abstract level, and return to the actual physics of our 4D spacetime and matter as late as possible.

The latter makes a lot of sense as you better unlearn some things you took for granted about vector and tensor calculus in flat space. A vector must no longer be visualized as an arrow that can be moved around carelessly in space, and one must be very careful in visualizing what transforming coordinates really means.

For motivation or as an ‘upper level pop-sci intro’…

Richard Feynman’s lecture on curved space might be a very good primer. Feynman explains what curved space and curved spacetime actually mean. Yes, he is using that infamous beetle on a balloon, but he also gives some numbers obtained by back-of-the-envelope calculations that explain important concepts.

For learning about the mathematical foundations …

I cannot praise these Lectures given at the Heraeus International Winter School Gravity and Light 2015 enough. Award-winning lecturer Frederic P. Schuller goes to great lengths to introduce concepts carefully and precisely. His goal is to make all implicit assumptions explicit and avoid allusions to misguided ‘intuitions’ one might got have used to when working with vector analysis, tensors, gradients, derivatives etc. in our tangible 3D world – covered by what he calls ‘undergraduate analysis’. Only in lecture 9 the first connection is made back to Newtonian gravity. Then, back to math only for some more lectures, until finally our 4D spacetime is discussed in lecture 13.

Schuller mentions in passing that Einstein himself struggled with the advanced math of his own theory, e.g. in the sense of not yet distinguishing clearly between the mathematical structure that represents the real world (a topological manifold) and the multi-dimensional chart we project our world onto when using an atlas. It is interesting to pair these lectures with this paper on the history and philosophy of general relativity – a link Joseph Nebus has pointed to in his post on covariance.

Learning physics or math from videos you need to be much more disciplined than with plowing through textbooks – in the sense that you absolutely have to do every single step in a derivation on your own. It is easy to delude oneself that you understood something by following a derivation passively, without calculating anything yourself. So what makes these lectures so useful is that tutorial sessions have been recorded as well: Tutorial sheets and videos can be found here.
(Edit: The Youtube channel of the event has not all the recordings of the tutorial sessions, only this conference website has. It seems the former domain does not work any more, but the content is perserved at

You also find brief notes for these lectures here.

For a ‘physics-only’ introduction …

… I picked a classical, ‘legendary’ resource: Landau and Lifshitz give an introduction to General Relativity in the last third of the second volume in their Course of Theoretical Physics, The Classical Theory of Fields. Landau and Lifshitz’s text is terse, perhaps similar in style to Dirac’s classical introduction to quantum mechanics. No humor, but sublime and elegant.

Landau and Lifshitz don’t need manifolds nor tangent bundles, and they use the 3D curvature tensor of space a lot in addition to the metric tensor of 4D spacetime. They introduce concepts of differences in space and time right from the start, plus the notion of simultaneity. Mathematicians might be shocked by a somewhat handwaving, ‘typical physicist’s’ way to deal with differentials, the way vectors on different points in space are related, etc. – neglecting (at first sight, explore every footnote in detail!) the tower of mathematical structures you actually need to do this precisely.

But I would regard Lev Landau sort of a Richard Feynman of The East, so it takes his genius not make any silly mistakes by taking the seemingly intuitive notions too literally. And I recommend this book only when combined with a most rigorous introduction.

For additional reading and ‘bridging the gap’…

I recommend Sean Carroll’s  Lecture Notes on General Relativity from 1997 (precursor of his textbook), together with his short No-Nonsense Introduction to GR as a summary. Carroll switches between more intuitive physics and very formal math. He keeps his conversational tone – well known to readers of his popular physics books – which makes his lecture notes a pleasure to read.

Artist's concept of general relativity experiment (Public Domain, NASA, Wikimedia)


So this was a long-winded way to present just a bunch of links. This post should also serve as sort of an excuse that I haven’t been really active on social media or followed up closely on other blogs recently. It seems in winter I am secluding myself from the world in order to catch up on theoretical physics.

Give the ‘Thing’ a Subnet of Its Own!

To my surprise, the most clicked post ever on this blog is this:

Network Sniffing for Everyone:
Getting to Know Your Things (As in Internet of Things)

… a step-by-step guide to sniff the network traffic of your ‘things’ contacting their mothership, plus a brief introduction to networking. I wanted to show how you can trace your networked devices’ traffic without any specialized equipment but being creative with what many users might already have, by turning a Windows PC into a router with Internet Connection Sharing.

Recently, an army of captured things took down part of the internet, and this reminded me of this post. No, this is not one more gloomy article about the Internet of Things. I just needed to use this Internet Sharing feature for the very purpose it was actually invented.

The Chief Engineer had finally set up the perfect test lab for programming and testing freely programmable UVR16x2 control systems (successor of UVR1611). But this test lab was a spot not equipped with wired ethernet, and the control unit’s data logger and ethernet gateway, so-called CMI (Control and Monitoring Interface), only has a LAN interface and no WLAN.

So an ages-old test laptop was revived to serve as a router (improving its ecological footprint in passing): This notebook connects to the standard ‘office’ network via WLAN: This wireless connection is thus the internet connection that can be shared with a device connected to the notebook’s LAN interface, e.g. via a cross-over cable. As explained in detail in the older article the router-laptop then allows for sniffing the traffic, – but above all it allows the ‘thing’ to connect to the internet at all.

This is the setup:

Using a notebook with Internet Connection Sharing enabled as a router to connect CMI (UVR16x2's ethernet gatway) to the internet

The router laptop is automatically configured with IP address and hands out addresses in the 192.168.137.x network as a DHCP server, while using an IP address provided by the internet router for its WLAN adapter (indicated here as commonly used 192.168.0.x addresses). If Windows 10 is used on the router-notebook, you might need to re-enable ICS after a reboot.

The control unit is connected to the CMI via CAN bus – so the combination of test laptop, CMI, and UVR16x2 control unit is similar to the setup used for investigating CAN monitoring recently.

The CMI ‘thing’ is tucked away in a private subnet dedicated to it, and it cannot be accessed directly from any ‘Office PC’ – except the router PC itself. A standard office PC (green) effectively has to access the CMI via the same ‘cloud’ route as an Internet User (red). This makes the setup a realistic test for future remote support – when the CMI plus control unit has been shipped to its proud owner and is configured on the final local network.

The private subnet setup is also a simple workaround in case several things can not get along well with each other: For example, an internet TV service flooded CMI’s predecessor BL-NET with packets that were hard to digest – so BL-NET refused to work without a further reboot. Putting the sensitive device in a private subnet – using a ‘spare part’ router, solved the problem.

The Chief Engineer's quiet test lab for testing and programming control units

And Now for Something Completely Different: Rotation Heat Pump!

Heat pumps for space heating are all very similar: Refrigerant evaporates, pressure is increased by a scroll compressor, refrigerant condenses, pressure is reduced in an expansion value. *yawn*

The question is:

Can a compression heat pump be built in a completely different way?

Austrian start-up ECOP did it: They  invented the so-called Rotation Heat Pump.

It does not have a classical compressor, and the ‘refrigerant’ does not undergo a phase transition. A pressure gradient is created by centrifugal forces: The whole system rotates, including the high-pressure (heat sink) and low-pressure (source) heat exchanger. The low pressure part of the system is positioned closer to the center of the rotation axis, and heat sink and heat source are connected at the axis (using heating water). The system rotates at up to 1800 rounds per minute.

A mixture of noble gases is used in a Joule (Brayton) process, driven in a cycle by a ventilator. Gas is compressed and thus heated up; then it is cooled at constant pressure and energy is released to the heat sink. After expanding the gas, it is heated up again at low pressure by the heat source.

In the textbook Joule cycle, a turbine and a compressor share a common axis: The energy released by the turbine is used to drive the compressor. This is essential, as compression and expansion energies are of the same order of magnitude, and both are considerably larger than the net energy difference – the actual input energy.

In contrast to that, a classical compression heat pump uses a refrigerant that is condensed while releasing heat and then evaporated again at low pressure. There is no mini-turbine to reduce the pressure but only an expansion valve, as there is not much energy to gain.

This explains why the Rotation Heat Pumps absolutely have to have compression efficiencies of nearly 100%, compared to, say, 85% efficiency of a scroll compressor in heat pump used for space heating:

Some numbers for a Joule process (from this German ECOP paper): On expansion of the gas 1200kW are gained, but 1300kW are needed for compression – if there would be no losses at all. So the net input power is 100kW. But if the efficiency of the compression is reduced from 100% to 80% about 1600kW are needed and thus a net input power of 500kW – five times the power compared to the ideal compressor! The coefficient of performance would plummet from 10 to 2,3.

I believe these challenging requirements are why Rotation Heat Pumps are ‘large’ and built for industrial processes. In addition to the high COP, this heat pump is also very versatile: Since there are no phase transitions, you can pick your favorite corner of the thermodynamic state diagram at will: This heat pump works for very different combinations temperatures of the hot target and the cold source.

Same Procedure as Every Autumn: New Data for the Heat Pump System

October – time for updating documentation of the heat pump system again! Consolidated data are available in this PDF document.

In the last season there were no special experiments – like last year’s Ice Storage Challenge or using the wood stove. Winter was rather mild, so we needed only ~16.700kWh for space heating plus hot water heating. In the coldest season so far – 2012/13 – the equivalent energy value was ~19.700kWh. The house is located in Eastern Austria, has been built in the 1920s, and has 185m2 floor space since the last major renovation.

(More cross-cultural info:  I use thousands dots and decimal commas).

The seasonal performance factor was about 4,6 [kWh/kWh] – thus the electrical input energy was about 16.700kWh / 4,6 ~ 3.600kWh.

Note: Hot water heating is included and we use flat radiators requiring a higher water supply temperature than the floor heating loops in the new part of the house.

Heating season 2015/2016: Performance data for the 'ice-storage-/solar-powered' heat pump system

Red: Heating energy ‘produced’ by the heat pump – for space heating and hot water heating. Yellow: Electrical input energy. Green: Performance Factor = Ratio of these energies.

The difference of 16.700kWh – 3.600kWh = 13.100kWh was provided by ambient energy, extracted from our heat source – a combination of underground water/ice tank and an unglazed ribbed pipe solar/air collector.

The solar/air collector has delivered the greater part of the ambient energy, about 10.500kWh:

Heating season 2015/2016: Energy harvested from air by the collector versus heating-energy

Energy needed for heating per day (heat pump output) versus energy from the solar/air collector – the main part of the heat pump’s input energy. Negative collector energies indicate passive cooling periods in summer.

Peak Ice was 7 cubic meters, after one cold spell of weather in January:

Heating season 2015/2016: Temperature of ambient air, water tank (heat source) and volume of water frozen in the tank.

Ice is formed in the water tank when the energy from the collector is not sufficient to power the heat pump alone, when ambient air temperatures are close to 0°C.

Last autumn’s analysis on economics is still valid: Natural gas is three times as cheap as electricity but with a performance factor well above three heating costs with this system are lower than they would be with a gas boiler.

Is there anything that changed gradually during all these years and which does not primarily depend on climate? We reduced energy for hot tap water heating – having tweaked water heating schedule gradually: Water is heated up once per day and as late as possible, to avoid cooling off the hot storage tank during the night.

We have now started the fifth heating season. This marks also the fifth anniversary of the day we switched on the first ‘test’ version 1.0 of the system, one year before version 2.0.

It’s been about seven years since first numerical simulations, four years since I have been asked if I was serious in trading in IT security for heat pumps, and one year since I tweeted:

Spam Poetry: “Cris-Crossing the Universe”

I have tried my hands at different kinds of experimental internet poetry, and all of the poems turned out to have a dystopic touch or tantalizing hints to some fundamental philosophical truth. Perhaps this says something about 1) The Internet or 2) about my subconsciousness.

Since I have reduced blogging frequency, the number of spam comments plummeted accordingly – from 600 to 150 spam comments in the queue. So it has got harder and harder to find meaningful spam. In addition, there is a new variety: Such comments are not composed of meaningful sentences, but phrases of three or four words are stitched together to form a lengthy comment that sounds like postmodern poetry in its own right.

But I try to rise to the challenge, and even add one more hurdle. Rules for this poem:

  • Each line is a snippet of a spam comment.
  • Snippets must not be edited
  • Only one snippet can be extracted from one spam comment, but not every comment has to be utilized.
  • New: Snippets must be used immediately in the order of spam comments (descending by date), and they must not be re-arranged afterwards.
  • All comments have to be harvested in a single session.

The following lines were taken from about 125 spam comments in the queue on October 1st.

The idea shows through the pamphlet
where people need to respond

temperatures will most likely govern
long-lasting usable cartoon figures

in certain places the floor is sinking
We have a very big problem.

withdrawal insomnia
The arrangement exists because of the persistence

arrangement - persistence

using ontology within all things
There should be one internal link

You’ll be able to move to another location
Could certainly come zombies

A Dreamcatcher bard who have been heard
sober as opposed to
stepping off point
the one that has problems with panic attack

We will dissect too
cris-crossing the universe far far.

cris-crossing the universe

Scattered all over
the location where the profits have been

conspiracy delayed
raving about choosing real humans

our personal fashionable ethos
As opposed to the isolation
produced by Zombie galleries
creating an irritatingly low experience

in the sci fi shooting living space
extremely like black topics

Our favorite self-theory
That particular creep
seriously electrifying

seriously electrifying

Internet of Things. Yet Another Gloomy Post.

Technically, I work with Things, as in the Internet of Things.

As outlined in Everything as a Service many formerly ‘dumb’ products – such as heating systems – become part of service offerings. A vital component of the new services is the technical connection of the Thing in your home to that Big Cloud. It seems every energy-related system has got its own Internet Gateway now: Our photovoltaic generator has one, our control unit has one, and the successor of our heat pump would have one, too. If vendors don’t bundle their offerings soon, we’ll end up with substantial electricity costs for powering a lot of separate gateways.

Experts have warned for years that the Internet of Things (IoT) comes with security challenges. Many Things’ owners still keep default or blank passwords, but the most impressive threat is my opinion is not hacking individual systems: Easily hacked things can be hijacked to serve as zombie clients in a botnet and lauch a joint Distributed Denial of Service attack against a single target. Recently the blog of renowned security reporter Brian Krebs has been taken down, most likely as an act of revenge by DDoSers (Crime is now offered as a service as well.). The attack – a tsunami of more than 600 Gbps – was described as one of the largest the internet had seen so far. Hosting provider OVH was subject to a record-breaking Tbps attack – launched via captured … [cue: hacker movie cliché] … cameras and digital video recorders on the internet.

I am about the millionth blogger ‘reporting’ on this, nothing new here. But the social media news about the DDoS attacks collided with another social media micro outrage  in my mind – about seemingly unrelated IT news: HP had to deal with not-so-positive reporting about its latest printer firmware changes and related policies –  when printers started to refuse to work with third-party cartridges. This seems to be a legal issue or has been presented as such, and I am not interested in that aspect here. What I find interesting is the clash of requirements: After the DDoS attacks many commentators said IoT vendors should be held accountable. They should be forced to update their stuff. On the other hand, end users should remain owners of the IT gadgets they have bought, so the vendor has no right to inflict any policies on them and restrict the usage of devices.

I can relate to both arguments. One of my main motivations ‘in renewable energy’ or ‘in home automation’ is to make users powerful and knowledgable owners of their systems. On the other hand I have been ‘in security’ for a long time. And chasing firmware for IoT devices can be tough for end users.

It is a challenge to walk the tightrope really gracefully here: A printer may be traditionally considered an item we own whereas the internet router provided by the telco is theirs. So we can tinker with the printer’s inner workings as much as we want but we must not touch the router and let the telco do their firmware updates. But old-school devices are given more ‘intelligence’ and need to be connected to the internet to provide additional services – like that printer that allows to print from your smartphone easily (Yes, but only if your register it at the printer manufacturer’s website before.). In addition, our home is not really our castle anymore. Our computers aren’t protected by the telco’s router / firmware all the time, but we work in different networks or in public places. All the Things we carry with us, someday smart wearable technology, will check in to different wireless and mobile networks – so their security bugs should better be fixed in time.

If IoT vendors should be held accountable and update their gadgets, they have to be given the option to do so. But if the device’s host tinkers with it, firmware upgrades might stall. In order to protect themselves from legal persecution, vendors need to state in contracts that they are determined to push security updates and you cannot interfere with it. Security can never be enforced by technology only – for a device located at the end user’s premises.

It is horrible scenario – and I am not sure if I refer to hacking or to proliferation of even more bureaucracy and over-regulation which should protect us from hacking but will add more hurdles for would-be start-ups that dare to sell hardware.

Theoretically a vendor should be able to separate the security-relevant features from nice-to-have updates. For example, in a similar way, in smart meters the functions used for metering (subject to metering law) should be separated from ‘features’ – the latter being subject to remote updates while the former must not. Sources told me that this is not an easy thing to achieve, at least not as easy as presented in the meters’ marketing brochure.

Linksys's Iconic Router

That iconic Linksys router – sold since more than 10 years (and a beloved test devices of mine). Still popular because you could use open source firmware. Something that new security policies might seek to prevent.

If hardware security cannot be regulated, there might be more regulation of internet traffic. Internet Service Providers could be held accountable to remove compromised devices from their networks, for example after having noticed the end user several times. Or smaller ISPs might be cut off by upstream providers. Somewhere in the chain of service providers we will have to deal with more monitoring and regulation, and in one way or other the playful days of the earlier internet (romanticized with hindsight, maybe) are over.

When I saw Krebs’ site going offline, I wondered what small business should do in general: His site is now DDoS-protected by Google’s Project Shield, a service offered to independent journalists and activists after his former pro-bono host could not deal with the load without affecting paying clients. So one of the Siren Servers I commented on critically so often came to rescue! A small provider will not be able to deal with such attacks. should be well-protected, I guess. I wonder if we will all end up hosting our websites at such major providers only, or ‘blog’ directly to Facebook, Google, or LinkedIn (now part of Microsoft) to be safe. I had advised against self-hosting WordPress myself: If you miss security updates you might jeopardize not only your website, but also others using the same shared web host. If you live on a platform like WordPress or Google, you will complain from time to time about limited options or feature updates you don’t like – but you don’t have to care about security. I compare this to avoiding legal issues as an artisan selling hand-made items via Amazon or the like, in contrast to having to update your own shop’s business logic after every change in international tax law.

I have no conclusion to offer. Whenever I read news these days – on technology, energy, IT, anything in between, The Future in general – I feel reminded of this tension: Between being an independent neutral netizen and being plugged in to an inescapable matrix, maybe beneficial but Borg-like nonetheless.