Sirvi Autor "Hart, J." järgi

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Atmospheric attenuation of the Ku band along the space-earth path due to clouds and rain
(2020) Dvořák, J.; Hart, J.; Kumhálová, J.
The weather conditions formed in troposphere causes the greatest signal attenuation in satellite communication systems especially at frequencies above 10 GHz. This paper describes possible signal attenuations on the satellite-earth path due to rain and clouds. It was measured whether it is advantageous to use the Ku band for data transmission over other bands. The measurement was carried out in the Czech Republic using a beacon signal from Eutelsat 12W satellite at 12.5 GHz. Clouds and the rainfall rate at the measured location were obtained from the CHMI portal. The measurements show that the clouds cause negligible attenuation. Significant attenuation was caused by rainfall. The measured values of slant path rain show a significant decrease in signal strength even in light rain. The measured cumulative rainfall rate was found to be close to the ITU-R model. The measurements show that the Ku band is advantageous for data transmission in rain poorer regions including Central Europe.
Detection reliability for passive infrared detectors in intrusion and hold-up alarm systems and their ergonomics
(2018) Hart, J.; Hartová, V.
Currently it is highly important for detectors to be able to achieve efficiency, reliability, and faultless operation, and to be ergonomic thanks to their assembly and being easy-to-fit. In the case of a proposal for the placement of detectors it is naturally important to determine position of the detector and the type of detector being used, but also to guarantee their capability to be able to detect anything when in use and their user and installation-friendliness. The problem of passive infrared (PIR) detectors affects a large proportion of intrusion and hold-up alarm systems (I&HAS). In a time of increasing property crime, it is highly important for PIR detector to actually be able to detect break-in attempts within the guarded area on a reliable basis and free of error. In the case of the installation of PIR detectors, it is naturally important not only to ensure correct installation, to gauge the external influences which may impact upon the detector and to ensure proper maintenance, but also to guarantee the capability of detection under more arduous conditions. The tests and comparisons which have been conducted examine both the normal operation of the PIR detectors and the ergonomics of these detectors. These tests are important both from an informative perspective and due to the opportunities to be able to develop potential counter-measures which could lead to their improvement.
Development of new elements to automatized greenhouses
(2018) Hart, J.; Hartová, V.
Development of new elements to automatized of greenhouses is always needed and be it is to improve the current situation because of the increase effectivity in greenh ouses or their control. Czech University of Life Sciences Prague was to increase efficiency in greenhouses and therefore, devices designed to improve the automation in greenhouses have been designed and patented. The aim was to propose new improvements for automated greenhouses based on demand. This is primarily about solving the problem of lack of daylight and regularly occurring moss on the roof. This research and development are guided primarily because it is a agriculture branch in the stage of expansio n, and it is essential that there is a continuous innovation and research in this field of science. New automatic features or upgrades to existing features in greenhouses, was solved on the basis of the current state of development curent technology. When designet new technologies also help us grants, personal experience with a real installation and cooperation with manufacturers (or with distributors) greenhouses systems. Designs for a light routing system and a system for removing moss from the roof were made.
Improvement of monitoring of cattle in outdoor enclosure using IQRF technology
(2018) Hartová, V.; Hart, J.
Monitoring of cattle in the outdoor enclosure is a very important issue. Currently, the increasingly stealing cows and other cattle from the pasture. For businesses that manage it, this is a very lossy business. For thieves, the electric fences, which are currently the most widespread, are easily surmountly. And the owner does not have a chance early on to learn the fact theft of catt le. For this reason, a system for monitoring cattle on outdoor enclosure using IQRF (intelligent local network topology ) technology has been developed. We have been dealing with this issue for a long time and the biggest problem was the monitoring of only the inner part of the enclosure. Previously, there was an overlap of monitoring in the area beyond grazing. This problem has been solved by using a shielded base for mounting IQRF receivers.
Influence of face lighting on the reliability of biometric facial readers
(2018) Hartová, V.; Hart, J.; Prikner, P.
At present, there is an increasing need to protect workplace entry and specially guarded premises. In addition to standard access systems on a chip cards are getting to the fore of biometric identification systems such as readers for fingerprint, biometric scans faces and others. Biometric readers face still improve, but still have a lot of blind spots, thanks to which their reliability and user - friendline ss decreases. One such problem is the light intensity in the room where the reading device is located. The varying intensity of the light in the room causes a different illumination of the person's face. It emphasizes or suppresses the main points of the f ace that needed for user authorization, and the whole identification process is prolonged and difficult. The reliability value is significantly different from the value given by the manufacturers. It is very important to highlight on this problem and begin to address it by altering the current production engineering .
Measurability of quality in fermentation process of rice wine by IoT in the field of industry 4.0
(2021) Vošahlík, J.; Hart, J.
The article inquiries into the issue of automation of the rice wine fermentation process in the field of industry 4.0. Fermentation is the process of converting D-glucose into ethanol along with oxidation of reduced coenzymes (fermentation). This is known as ethanol fermentation, which takes place anaerobically in the presence of yeast. The fermentation is being improved by automation (sensors, etc.). The main aim is to develop an experimental automation environment in industry 4.0 for the process of rice wine fermentation. During the rice wine fermentation process, variety of measurable attributes are created which affect the quality of the resulting product. They can be monitored with the help of automation elements (pH, temperature, humidity etc.). In case of an experimental environment development, it is therefore important to select appropriately the sensory that can record the measurable attributes. At the same time, the sensory must be at a level of reliability that guarantee their sufficient use in the mentioned experimental environment for the rice wine fermentation. The result is that, if the right environment is chosen, the quality of the fermented wine will improve.
Measurements of wireless detectors used to monitor animal movements in livestock farms
(2019) Hart, J.; Hartová, V.
At present, there is a great interest in monitoring and automating farm animals and livestock farming. There are many systems and methods to check the movement of animals in certain areas. One option is to use motion detectors. However, some installations are so specific that they require the use of wireless motion detectors. They not only have to fulfill their functional part but also have a sufficiently strong signal that should not interfere outside the defined ISM bands. Due to the frequent deployment of different types of these detectors, research has been carried out to monitor shortcomings in frequently used types of wireless detectors. This research defines which tested detectors are fully usable according to the standards and which need to be modified by the manufacturer. Also, based on measurements, the basic risks and recommendations for the use of individual types of tested detectors are defined.
Possibilities of monitoring cattle via GSM and A-GPS
(2019) Sirotek, A.; Hart, J.
Nowadays, people and things can be localized using GNSS (Global Navigation Satellite System) or GSM technology. Devices using Differential Global Positioning Systems may not be suitable for they computing and energy intensity. The GSM and A-GPS systems have certain limitations and disadvantages. They are different in accuracy, energy intensity and therefore they are suitable for different applications. Trackers can’t be effectively used to locate animals, monitor their movements, and observe their behaviour. They can also be used to search for stolen pets and farm animals. Unguarded herds of cattle are often the target of thieves. For reasons of crime, localization was tested by devices using GSM and A-GPS technology. Specifically, the quality of these localization methods has been tested. Has been addressed above all, accuracy, reliability, speed and consistency of individual methods. In addition, further measurements were made. Localization has been tested in different well-defined environments. This makes it possible to judge the quality of individual localization technology and to suggest the best use of individual technologies and their link.
Reliability of camera systems to recognize facial features for access to specialized production areas
(2020) Vošahlík, J.; Hart, J.
The article deals with ergonomics and reliability of camera systems for recognition of facial features and identify person for access to specialized areas. The monitoring of areas relates not only to crime, but it is also an integral part of access to specialized production areas (pharmaceutical production, chemical production, specialized food production, etc.). It is therefore important to adequately secure these premises using the relevant system. One of them is a system based on user identification using specific facial features. For this purpose, there are CCTV systems for recognition of facial features of different price categories (conventional cameras, semi-professional and professional) on the world market. However, problematic situations may occur when identifying. For example, by having the user partially masked face. This research is focusing on the problem. The main goal of the research is establishing the scale of negative impact, in case the identified person has partially masked face, on camera systems recognizing facial features, primarily on recognition time. The results are evaluated in detail. Some camera systems are not suitable in specialized production areas due to their insufficient recognition ability. From all the tested devices, the HIKVISION iDS-2CD8426G0 / F-I camera identification system has proved to be optimal for identification purposes. In the case of designing, it is therefore necessary to choose suitable camera systems that have ergonomics and reliability at a level that will guarantee their sufficient use in the mentioned areas, while decreasing comfort and user-friendliness as little as possible. By measuring the ergonomics and reliability of these CCTV systems, it can be stated that there are statistically significant differences between conventional, semi-professional and professional systems, and it’s not just a design change, but also a more efficient recognition method.
Reliability of palms security under difficult conditions
(2019) Hartová, V.; Hart, J.; Kotek, M.
Reliability of biometric identification systems is a much discussed topic and nowadays security of premises is very important. The work is focused on palms security research and reliability of the system under adverse conditions, the aim of the measurement was to determine the reliability of readers under adverse conditions that may occur in an industrial environment. Difficult conditions include dirty surface of hand by water, dust, oil and writing accessories. First, a sample measurement was carried out, where the hands of the subjects were washed and thoroughly dried. This measurement was used to compare with measurements under adverse conditions. The results show that the more viscous the fluid the lower the reliability and also dusty hands caused considerably distorted results. The reliability of biometric systems still needs to be improved, as it often happens that the real values do not match the parameters that are declared by the manufacturers. Certain conditions must be met for the proper functioning of palms security, so that identifying persons are allowed access to the protected areas and have not been repeatedly denied.
Reliability of parking assistants depending on the material of detected obstacles
(2019) Hartová, V.; Kotek, M.; Hart, J.; Pícha, Š.
Today's modern vehicles are equipped with a range of assistance systems to enhance road safety. The standard equipment of most cars are parking assistants. It turns out that not always sensors can reliably detect the obstacle on the travel path of the vehicle. The aim of the paper is to determine the reliability of the parking sensors depending on the material of the obstacle detected. The original parking assistants of Škoda Rapid, Škoda Octavia II, and Škoda Superb have been tested in laboratory conditions using obstacles made of various materials (glass, mirror, plastic, metal, cardboard ...) located at distance of 100 cm from the vehicle. Distance values of the original sets of parking assistants were measured during the measurement from onboard diagnostic vehicle using diagnostic kit VAG-COM. The real distance was checked using a calibrated gauge. The results of the research show, that original sets of parking assistants achieve significantly more accurate results with a wider coverage of the space being scanned. Material composition of obstacles has a great influence on the reliability of parking systems. Not every material can respond properly to parking sensors.
Suitability of 2.4 GHz and 5 GHz wireless communications in production processes
(2019) Hart, J.; Bradna, J.
Today, it is increasingly modern to use wireless transmissions in production. It is possible to send information messages, control messages and it is often possible to access the technologies as IoT (the Internet of Things). The aim of this work was to find out which of the selected Wi-Fi frequencies is more suitable for use in syrup processing equipment. The evaluation was performed on the basis of attenuation and download speed at each frequency (2.4 GHz and 5 GHz bandwidth). These frequencies have been chosen due to their massive deployment for wifi networks that currently dominate wireless communications. Measurements were made downloading files on different frequency bands. Mean and maximum data throughput and signal strengths were also measured. By measuring, it has been found that when using 2.4 GHz wireless Wi-Fi technology, you can very often encounter strong interference effects. Despite the theoretically worse 5 GHz frequency spread, you can achieve up to 30% better data throughput on average. The results show the suitability of 2.4 and 5 GHz Wi-Fi technology. The main finding is that, despite the worse frequency spread of 5 GHz, it is more appropriate. Not only due to speed but also in the future due to better transmission capacities and future channel expansion.
Testing of ISM band at remotes for unlocking vehicles
(2018) Hart, J.; Hartová, V.
Every modern car has a remote control for wireless unlocking. Wireless drivers for unlocking the vehicle using frequency in the ISM bands. ISM bands are unlicensed bands. They are usually used for industrial, medical and scientific purposes. The question is whether wireless transmission parameters are sufficient and do not violate defined range of ISM band. Another important aspect is the security of the wireless transmissions and any other signal interference. The problem of interference plays an important role in ensuring the quality and safety of wireless communications, especially when wireless networks can be found everywhere. The issues of remote control vehicles is very important due to the resulting security of a guarded vehicle. One of the major risks that may occur are data transmission that the signal is blocked by another signal and the end user does not notice. In this case, does not lock the vehicle nor ensuring its securing security system. Tests which were performed accurately determined the bandwidth of broadcast remote control for each vehicle. Vehicles for which the tests were conducted are standard vehicles used to frequent occurrence. These are the following types: Alfa Romeo, Hyundai, Mercedes, Škoda and Toyota. Subsequently, the analysis was performed of transmission compared with standard broadcast of jammers. All test drivers worked in the band ISM433. These tests clearly demonstrated that not every manufacturer strictly observes ranges of ISM band. This may affect traffic on surrounding licensed bands.

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