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No. 13/2018 (March 26, 2018)
The researchers used tissue paper soaked in water with carbon nanotubes whose walls were made of graphene, a one-atom graphite layer. The paper had both horizontal and vertical fibers that conducted electricity. When the paper was deformed or torn, the conductivity changes could indicate what happened.
A sensor for measuring the pressure of the foot on the ground
(source: Dennis R. Wise / University of Washington)
(source: Dennis R. Wise / University of Washington)
Small, disposable sensors will certainly find applications in various fields. Some examples are the monitoring a person's gait or movement of their eyes. The collected data can be used to examine brain activity or to monitor exercises of athletes. For now, the researchers at the University of Washington have not stepped outside the laboratory, but they have a deep hope that they will soon be able to commercialize their invention.
How to additionally protect Hikvision IP CCTV systems?
One of the additional methods of protecting Hikvision network products is IP filtering. This functionality can be performed directly by each device and limit access to it only from allowed IP addresses. The typical configuration allows access only from IP addresses of the server that hosts the iVMS-4200 application software.
SMATV system in an apartment building with four staircases.
Multiswitch installations in multifamily buildings must be carefully designed. In the calculations, the input parameters include network topology, type and number of the multiswitches, the type of cable used (attenuation) and the lengths of its sections. The designer has to select the system components so that signal levels in all antenna outlets are within the recommended range.Below we present a design of such a system created with the use of SatNet software. The system in a residential building with 64 apartments situated on four floors in 4 staircases, is based on TERRA multiswitches of MV-9XX series with die-cast housings having increased screening efficiency (class A). The signal lines are split for the subnetwork in each staircase with the use of 9-path SAT/TV splitters splitters and SAT/TV taps with appropriate attenuation levels.
The layout of the system: 9-cable bus runs from the master antenna on the roof of the building to the amplifier located in the upper part of the outermost staircase, then is led downwards in the vertical cable duct to the basement level, split and led horizontally to other staircases. Each staircase is equipped with installation box with SAT/TV splitter/tap and MV-916L R70866 multiswitch for distribution of the signals to outlets in apartments located in the staircase.
Positioning of the camera for license plate recognition (LPR).
For the maximum effectiveness of license plate recognition, the camera supporting this functionality, e.g. DS-2CD4A26FWD-IZS/P (2.8-12 mm) K17893 or DS-2CD4A26FWD-IZS/P (8-32 mm) K17894, should be installed in a suitable manner, so that the images of the plates on cars are appropriately captured. There can be differences in requirements for placing the cameras and for the required numbers of pixels that correspond with the images of license plates.Before choosing the installation place, the user should consider some guidelines that must be met, such as the right viewing angle of the camera, the distance at which the camera should be mounted to the site of detection, and the corresponding size of the license plate in the image. Here are some common installation requirements for Hikvision cameras dedicated for license plate recognition:
- the width of the image of license plate should be within 130 - 300 pixels (optimum: 150-200 pixels);
- maximum vertical viewing angle: 30°;
- maximum horizontal viewing angle: 30°;
- the angle difference between the horizontal edge of the image and the horizontal edge of the plate (tilt) should not exceed +/-5°.
Diagram illustrating the positioning of an LPR camera in the vertical plane, where:
| X- height of the camera mounting location, Y - horizontal distance between the mounting location and detection point (measured on the ground), Z - distance from the camera to the detection point. | |
Elements of optical fiber structure for trouble-free splicing operations.
Knowledge of the construction of optical fibers is absolutely necessary in order to perform any joining operations. Novice installers who have not even completed basic fiber-optic training in this field have problems resulting from the lack of knowledge. Unfortunately, the problems connected with improper positioning of fiber ends in the holders of fusion splicers or with wrong preparation and mounting of the ends in mechanical splices are often the cause of failures.
The above figure shows the standardized construction of optical fibers. In the middle there is a core made of silica glass, often doped with various materials. The core transmits the light signal (the "mode" in the case of a single-mode fiber with typical core diameter of 9 μm, or many modes in the case of a multimode fiber with core diameter of 50 μm). The next layers are normally identical in the both kinds of fibers, i.e. the glass cladding with diameter of 125 μm and acrylic buffer with a diameter of 250 μm. Fibers used in pigtails and in some other cables have additional protective coating (called secondary buffer or jacket) with a diameter of 900 μm.
Irrespective of the splicing method, before this operation any fiber end has to be properly prepared by removing all layers above the 125 μm cladding. For most fiber-optic fibers, it can be done in one step, just by stripping the acrylic layer of 250 μm diameter. In the case of pigtails, it is necessary to make it in two steps - to remove the 900 μm and then the 250 μm coating. After the operation(s) the fiber end has to be cleaned and cleft.
A comparison of 2 pigtails with the same structure of the fibers but different colors of the 250 μm buffer.
To perform splicing operations, in both cases the installer has to remove the buffer layer.
To perform splicing operations, in both cases the installer has to remove the buffer layer.
The above picture shows the cause of the most common problems associated with the splicing of pigtails. All pigtails have 900 μm jackets, which may be yellow (single-mode pigtails) or orange (multimode pigtails). The acrylic coating underneath with a diameter of 250 μm can be colored or colorless. Some installers mistakenly regard the colorless buffer as the 125 μm cladding and do not remove it before the splicing process. Such negligence is the reason for many problems with joining fibers and makes it impossible to do it correctly.
Markings of twisted-pair cables.
Twisted-pair (balanced) cables are used to transmit signals in telecommunication systems and computer networks. Currently they are mainly used in analog telephony and Ethernet networks. Twisted-pair cables may consist of one or more pairs. The twisting strongly reduces the influence of external electromagnetic interference and mutual interference between the pairs, called crosstalk.![CAT 6A U/FTP Shielded Cable: NETSET U/FTP 6A [500m], indoor](https://static.dipol.com.pl/images/sk/pict/e1616_500++.jpg)
The newest type of twisted-pair cable offered by DIPOL:
NETSET U/FTP 6A E1616_500 shielded cable for indoor application
NETSET U/FTP 6A E1616_500 shielded cable for indoor application
Acronyms for balanced cables are standardized by ISO/IEC 11801:2002. The information contained in the cable description should have the following syntax: xx/yyTP, where the letters yy characterize individual wires/pairs and the letters xx describe the overall construction of the cable.
The xx and yy markings can be as follows:
- U – unshielded
- F – foiled (screened with foil)
- S – shielded (screened with braid)
- SF – shielded and foiled
- U/UTP – unscreened cable: E1408, E1410, E1412, E1608
- F/UTP – foil screened cable: E1515, E1517, E1519
- U/FTP – unscreened cable with foil screened pairs: E1616
- F/FTP – foil screened cable with foil screened pairs
- SF/UTP – overall braid and foil screened cable with unscreened balanced elements
- S/FTP – overall braid screened cable with foil screened pairs
- SF/FTP – overall braid and foil screened cable with foil screened pairs
 | SATEL VERSA IP (main board, 5 inputs) G2047 intruder alarm control panel is intended for small and medium commercial and residential security systems. The systems can be based both on wired and wireless solutions. The panel can cooperate with controllers of wireless ABAX system (ACU-120 and ACU-270) offering the capability to expand it with wireless devices of the ABAX family (sensors, signalling devices, manipulators/keypads), with two-way communication with confirmation of all transmissions. VERSA IP combines functions that so far were performed by a number of separate devices. | |
 | IP (100/1000Mbps) to 4x DVB-C Transmodulator TERRA miq-440 R81631 converts IP stream (TSoIP) provided in UDP/RTP protocols (unicast/multicast SPTS and MPTS transmissions) to four DVB-C QAM multiplexes. The miq-440 R81631 panel receives IP stream with bit rate up to 200 Mbps and creates freely configurable four neighboring DVB-C multiplexes, each with maximum bit rate up to 53 Mbps (the limit is determined by the DVB-C standard). In practice, each of the four multiplexes can carry 8 SD channels or 4-5 HD channels. | |
 | Single-cable Cascadable dSCR Multiswitch Terra SRM-581 R80581 allows for distribution of DVB-S/S2 signals from one satellite and terrestrial signals (DVB-T, DAB+/FM radio). The satellite signals can be distributed by means of dSCR technology (digital Satellite Cable Router), requiring only one coaxial line and satellite splitters to provide the signals to compatible SAT receivers, along with terrestrial signals that can be received by standard televisions and radios. The SRM-581 R80581 multiswitch fully supports receivers operating in two dynamic modes: SCR (Unicable I - 8 User Bands) and dSCR (Unicable II - 32 User Bands). | |
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