DIPOL Weekly Review – TV and SAT TV, CCTV, WLAN

CHIPS - 3D printed collagen scaffolds.

A team of researchers at the University of Pittsburgh led by Dr Daniel Shiwarski has created a new tissue culture platform that mimics the natural cellular environment. They used biocompatible collagen and 3D printing technology. CHIPS enable the creation of realistic models of diseases such as diabetes and hypertension. They make it possible to eliminate the need for animal testing. Published in the prestigious journal Science Advances, the research shows that the new scaffolds could revolutionise regenerative medicine and drug research. CHIPS designs are available to the public, encouraging further development of the technology. Unlike traditional synthetic models, CHIPS are made exclusively from collagen - a natural protein present in organisms. This allows cells to grow, communicate and self-organise into functional tissues inside these scaffolds. The team of researchers combined collagen with blood vessel and pancreatic cells, resulting in an insulin response to glucose - exactly as it happens in the human body. To further support the development of such tissues, the researchers created a proprietary perfusion bioreactor called VAPOR, which works with CHIPS like Lego bricks - easily and safely connecting the structures.

In contrast to the flat models used previously, CHIPS allow the creation of complex, spatial vascular networks that resemble the structure of the DNA double helix. This opens up new possibilities in mapping the physiology of human organs in a laboratory setting. "We are combining the best of microfluidics - control of flow and vascular structures - with natural materials and the biological intelligence of cells," - Dr Shiwarski says. - "In the right environment, the cells themselves know what to do: they grow, adapt and form complex tissues." The team aims to replace animal testing altogether and is making its models and designs available to the public in the spirit of open science. Another goal is to use CHIPS to study vascular diseases - such as hypertension or fibrosis - and understand how they affect tissue development and function. "With this platform, we can bridge the gap between simple 2D models and animal studies." - Shiwarski adds. "This allows us to model human diseases more accurately and, in the future, to create more effective therapies."

Dynamics vs. resolution of the reflectometer.

Dynamics or dynamic range is a parameter of a reflectometer that tells you about the measurement capabilities of the device in terms of maximum line attenuation. This parameter is expressed in dB and usually takes values in the range 20 dB - 40 dB. In simple terms, it tells you what maximum attenuation the measured line can reach before the noise in the reflectogram prevents any interpretation of the measurement. For example, a dynamic of 20 dB will in theory allow 50 km of fibre to be measured (20 / 0.4 dB/km (fibre attenuation) = 50 km). If the measured line was 10 km (4 dB attenuation), but contained 2 8-output splitters (2x 10 dB attenuation = 20 dB), the 20 dB dynamic range would be insufficient. The attenuation will, of course, also be affected by all the connectors, if present in the link.

In the context of the dynamic range and its values in the data sheets for the devices, it is worth bearing in mind two things: firstly, this parameter is variable depending on the width of the pulse used in the measurement, and the value shown in the data sheets is the value for the largest pulse. The exact dynamic range values for smaller pulses are not known. Secondly, there is the concept of "useful dynamic range", according to which the range should be limited to the point where the reflectometer is able to correctly distinguish a 0.5 dB attenuation event on the reflectogram. The useful dynamic range is sometimes a few to several dB lower than the basic dynamic range specified by the manufacturer.

Increasing the dynamic range (in order to measure a line containing certain signal attenuation elements) by increasing the pulse width, has the negative consequence of increasing the so-called dead zones behind the connectors. Often, however, such concessions are necessary.

In the case of the ULTIMODE L5830 and L5835 reflectometers, access to the widest pulses is achieved by increasing the measurement range. When measuring a line containing cascades of splitters, it may be necessary to artificially increase the measurement range - for example, the aforementioned 10 km line with two splitters, would output a measurement with a range of 10 km. However, this range does not offer access to the widest pulses that may be necessary for measurement. Therefore, in selected situations we increase it to 80, 100 or 120 km gaining access to the maximum dynamic range of the reflectometer.

However, the supernormal increase in measurement range, in addition to the benefits of the greater dynamic range offered by wider pulses, has negative consequences. The measurement resolution (sometimes called 'sampling resolution'), which tells us the number of measurement points, is reduced. The reflectogram is represented as a continuous line, but in reality the number of measurement points is limited. A reduction in resolution results in a reduction in precision in the measurement of event distances. In the case of the ULTIMODE L5830 and L5835 reflectometers, the selection of the measurement range (and indirectly the dynamic range) from a specific range is associated with the following resolution:

RACK board - installation of multiswitches in a RACK cabinet.

RACK cabinets have become the standard in multi-family buildings for the organisation of telecommunication installations. Thanks to their functionality, universal dimensions (19" width, various heights in U units) and aesthetics, they enable the orderly installation of devices such as multiswitches, amplifiers, network switches, power supplies or patch panels.

This solution facilitates access to the infrastructure during maintenance or expansion, as well as providing a professional appearance to the entire installation. RACK cabinets make it possible to organise RTV-SAT, intercom, monitoring and computer network systems. Moreover, their design allows integration with power and ventilation systems, which translates into longer equipment life and greater operational stability. They are also an important element for meeting technical and safety standards in modern construction.

VLANs in monitoring networks.

As a standard, devices responsible for home security (monitoring, intercom, gate controllers, etc.) and home computer equipment should not be located on the same IP network. The separation of these devices from each other is one factor in increasing the security of the security system.

A way to separate these networks is to create virtual local networks. This requires the use of a managed switch and creation of dedicated VLANs. In the example below, by changing parameters on the switch, the user can create two separate networks. The first one will cover monitoring, and the second the home network. Both networks operate independently.

It is very important during configuration (and yet often overlooked) to manually assign IP addresses to devices without giving them a default gateway. Devices used for home security should not have direct access to the Internet. Also, remember to disable any cloud-based services (e.g. remote viewing). The administrator should only allow access to the internal network from the outside via a VPN (of course, this involves the need for an external IP address).

ODTR - measurement through a splitter on an active fibre. ULTIMODE OR-30 L5835 reflectometer, thanks to the possibility of generating pulses at 1625 nm and appropriate filters, enables measurements on an active line - in particular measurements in GPON networks containing splitters. An example of such a measurement performed on one's own network by one of the reflectometer's users is presented below...>>>more