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No. 18/2015 (May 4, 2015)
Will servers heat our homes?
Nerdalize, a Dutch company, together with Eneco, one of the largest energy suppliers in the Netherlands, have invented a great way to make better use of database servers. Until now, the heat generated during operation of the servers in data centers caused both technical and financial problems, and the energy was mostly wasted. The companies came up with an excellent idea of using this energy, creating Eneco eRadiator, the server combining the functionality of a high-performance server and ... controllable heater. From now on, the heat generated by the servers can be used for heating homes or other facilities, thus ensuring better performance and the sustainability of the entire system. The eRadiators may be located in private houses as a complement to the heating systems and can remotely distribute their computing power.
Eneco eRadiator - the way to minimize heating costs in homes in the cold seasons
The eRadiators currently tested in five Dutch homes are used for complex calculations carried out by a number of companies and research institutions. Naturally, Nederlize returns the cost of electricity used to power the servers, to make the undertaking beneficial for people who have installed the equipment. As a result, the home owners can use the heat generated by the servers virtually for free. And the company does not have to hire an IT staff and pay for the overhead of a data center. This way, it can offer computing power that is up to 55% cheaper in relation to the offers of other suppliers.
"These computers generate massive amounts of heat and then you start using energy to cool that down again, which is a bit of a waste. With the solution that Nerdalize has, we don't actually have to build the data center, which saves a lot of costs in infrastructure and we don't have the cooling overhead, plus that you have the environmental benefit, that the Kilowatt hour you are using is used twice, once to heat the home and once to compute the clients task without the cooling overhead," the Nerdalize's CEO Boaz Leupe told Reuters.
The benefit of the cooperation is mutual. The owner of the servers saves on the infrastructure and cooling, while the home owners benefit from free heating. Simply, both sides save money. The additional radiators support the existing heating systems and do not require any changes in the home installations. As the result, the systems consume less energy. The undertaking will be monitored throughout the year, and later the company will decide on the future of the project.
Screening efficiency of coaxial cables.
Coaxial cables are very important components of antenna systems. They have to effectively distribute the signals and protect them against external interferences, as well as from inter-channel crosstalk (multiswitch systems). A good coaxial cable should ensure low attenuation and high screening efficiency. The latter parameter is measured in the 5-3000 MHz frequency range and may differ a lot depending on the cable quality, from 45 dB to more than 120 dB. The highest values characterize high-quality RF cables of Triset series suitable for professional RF distribution systems (MATV/SMATV/CABLE TV), e.g. Triset-113 E1015.Classification of coaxial cables
in terms of minimum screening efficiency according to EN50117
| Class /freq. range | 5-30 MHz [mΩ/m] | 30-1000 MHz [dB] | 1-2 GHz [dB] | 2-3 GHz [dB] |
| C | <50.0 | >75 | >65 | >55 |
| B | <15.0 | >75 | >65 | >55 |
| A | <5.0 | >85 | >75 | >65 |
| A+ | <2.5 | >95 | >85 | >75 |
| A++ | <0.9 | >105 | >95 | >85 |
TRISET-113 cables fulfill screening requirements for Class A in the entire 30-3000 MHz frequency range. Above 100 MHz, the cables also satisfy the requirements for A+ class. Therefore, they can be used in installations where multiple antenna cables run in parallel over long distances.
In the lowest frequency range used in antenna systems (5-30 MHz), the main mechanism of signal penetration is different - magnetic fields from outside induce electric currents in the outer conductor, which induce interference voltages in the transmission line. The measure of this phenomenon is transfer impedance expressed in [mΩ/m], so given per unit length of the cable. This parameter is essential for cables used in CATV systems with return path, using this frequency range for Internet services.
How to overcome obstacles between WLAN nodes?
In many situations it is impossible to achieve a direct link between two locations that should be wirelessly connected. However, the lack of line-of-sight does not eliminate wireless technology. In most cases the solution is to create an intermediate node and a combination of two point-to-point links. The devices creating the intermediate node (that are usually located side-by-side) can be connected directly via Ethernet cable.
The transmission between the two outermost nodes is enabled by the intermediate node
with two additional MikroTik access points
with two additional MikroTik access points
Types of fiber splicers - which to choose?
Before purchasing a fusion splicer, the customer should necessarily determine the tasks to be performed. This refers, among others, to the average number of splicing operations on a monthly or annual basis, the number of splices done during one installation, and finally the kind of the networks (building, metropolitan, internal LANs, CCTV systems etc.).Depending on the answers to these questions, the customer can choose from many models of welding machines offered on the market, with various additional functions. However, the basic criterion should be the way of aligning the fiber ends before the welding process. Taking it into account, there are 3 groups:
- Splicers based on fiber cladding alignment - this is the most economical option; the splicer adjusts the mutual positions of their cladding to minimize the difference. Theoretically, such a method of positioning results in a weld having a slightly larger attenuation compared to other solutions, especially in the case of fibers of poor quality, where the core is not placed centrally with respect to the cladding. In practice, however, the fibers sold today are of high quality and in most cases the parameters of the splices performed with this method do not differ from results achieved with the use of other methods.
- Splicers with aligning geometric core positions - this method is used by the majority of the cheapest splicers and many manufacturers and retailers wrongly describe them as devices with aligning (actual) core positions; the core geometry is obtained by optical means (visible light). The intensity of light in the fiber decreases as a function of depth, and with a given sensitivity and simple image analysis, it is possible to determine the approximate positions of fiber cores. This method has been optimized for good quality fibers, where the geometric position of the core is equivalent to its real position. When the core is embedded eccentrically, the parameters of the splice can be worse than in the case of fiber cladding alignment.
- Splicers with alignment of (real) core positions - it is the most professional and at the same time the most expensive solution. The devices using this method can automatically recognize the type of welded fibers and arrange them according to their real cores. Such welds are characterized by the best performance parameters. The welding machines utilizing this method are several times more expensive than devices based on the previous solutions.
The EasySplicer L5810 is based on fiber cladding alignment
Splicers based on fiber cladding alignment can be successfully used in FTTH systems, in which, according to standards, the attenuation of any path in a building cannot exceed 1.2 dB, as well as in any fiber-optic networks where the lines between active devices have up to several splices. The examples are LANs, CCTV networks, or point-to-point links up to several kilometers.
In the case of hundreds or thousands of splices per month, it is advisable to invest in the most expensive equipment with the alignment of the real core positions, automatic operations, capable of performing great number of splicing cycles per battery charge etc.
In the case of hundreds or thousands of splices per month, it is advisable to invest in the most expensive equipment with the alignment of the real core positions, automatic operations, capable of performing great number of splicing cycles per battery charge etc.
Firmware update of Sunell NVRs and IP cameras.
The firmware of Sunell NVRs can be updated via UpdateClient application. In the field Add Device the user should enter the IP address of the NVR or IP camera and tick the Add online device option. The device becomes visible in the window and the user, after getting connect success status, can start the update process. After indicating the update file with the use of the Browse tab and entering the User name and Password (default: admin, admin), it is enough to click on the Update button. After the update is complete, the app displays update success message and the device automatically restarts, which takes approx. one minute, then it can normally work.
View of the window of UpdateClient app for updating Sunell NVRs and IP cameras
In the case of a problem with the detection of the device or an unsuccessful attempt to upgrade, the device can be updated offline. After receiving the connect success information, the updating process is identical as described above. The updating process should not be interrupted, as this could damage the equipment.
Ezviz service for Hikvision devices.
Hikvision company has introduced a new service called Ezviz (EasyVision), which can be activated in Hikvision NVRs and IP cameras. This free service allows less advanced users to easily access to the video from the cameras via the Internet. To enable remote access, the user should only connect the device to the network (which requires a valid IP address and appropriate gateway settings). The next step is the creation of user account at the www.ezviz7.com website. The account can accommodate devices in a local area network (with activated Ezviz service). The devices will be available from anywhere via the Internet. In addition, there are applications for mobile devices with Android and iOS, which in addition to viewing images from cameras allow users to set alarm notifications.
Viewing image from a Hikvision NVR via the Ezviz service
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News
April 28, 2015 - Chrome disables NPAPI plugins. The April update of Chrome disables NPAPI plugins. It results in problems with displaying images from Ultimax and Hikvision cameras and DVRs/NVRs via this browser (continually prompting for installation of plugins that are already installed). The plugins can be supported again by setting appropriate flag in the Chrome options. In the address bar, the user has to enter: chrome://flags/#enable-npapi and click on the activation option of the NPAPI interface. Then, the user should close all windows of the browser and run the browser again. However, this solution is temporary, due to the fact that the support for NPAPI will cease in September. The recommendation: there are no problems with Firefox or IE.
Chrome browser's message when trying to play video from Hikvision devices
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