In a smart city environment, Intelligent Transportation System (ITS) enables the vehicle to generate and communicate messages for safety applications. There exists a challenge where the integrity of the message needs to be verified before passing it on to other vehicles. There should be a provision to motivate the honest vehicles who are reporting the true event messages. To achieve this, traffic regulations and event detections can be linked with blockchain technology. Any vehicle violating traffic rules will be issued with a penalty by executing the smart contract. In case any accident occurs, the vehicle nearby to the spot can immediately send the event message to Unmanned Aerial Vehicle (UAV). It will check for its credibility and proceed with rewards. The authenticity of the vehicle inside the smart city area is verified by registering itself with UAVs deployed near the city entrance. This is enabled to reduce the participation of unauthorized vehicles inside the city zone. The Secure Hash Algorithm (SHA256) and Elliptic Curve Digital Signature Algorithm (ECDSA-192) are used for communication. The result of computation time for certificate generation and vehicles involvement rate is presented.

On the basis of a unipolar corona discharge, a method of non-contact and continuous measurement of linear parameters of thin and ultra-thin dielectric fibres and optical fibres (10 to 125 microns) in the process of their manufacture was developed. The measurement method differs from the commonly known methods by high accuracy and reliability of measurement and resistance to changes in the electrical characteristics of the discharge gap and the state of ambient air.

Copper have always been an important material and incorporation of elements into copper for property enhancement. Bronze is a relevant cuprous alloy which is important for many industrial and automotive applications like bearings and machineries. The present research is directed towards the fabrication and tribological analysis of regular bronze (Cu-6Sn) and metal matrix composites reinforced with varying particle sized SiC ceramic reinforcement (30, 35 and 40 μm). The developed specimens were subjected to wear analysis according to ASTM standards, to identify the tribological properties utilizing a pin on disk tribometer. It was noted that the wear rates of developed MMC’s phenomenally decremented with an increase in size of SiC particle reinforcement. Also, the test parameters were influential in altering the wear rates to notable margins. The standard scanning electron microscopy techniques aided in identifying the influence of adhesive wear on the specimen surface.

The paper discusses the problem of video transmission in an IP network. The authors consider the ability of using the most popular video codecs that use both the MPEG2 Transport Stream and Dynamic Adaptive Streaming over Hypertext Transfer Protocol (DASH). The main emphasis was given to ensuring the quality of service and quality assessment methods, taking into account not only the service- or network provider’s point of view but also the end user’s perspective. Two quality assessment approaches were presented, i.e. objective and subjective methods. The authors presented the results of the quality evaluation for H.264/MPEG-4, H.265/HEVC and VP9 codecs. The objective measurements, proved by statistical analysis of user opinion scores, confirmed the ability of using H.265 and VP9 codecs in both real time and streaming transmissions, while the quality of video streaming over HTTP with the H.264 codec proved inadequate. The authors also presented a connection between the dynamics of network bandwidth changing and MPEG-DASH mechanism operation and their influence on the quality experienced by users.

Transportation noise is a main source of noise pollution. It is assumed that it consists of recognizable noise events which come from moving aircrafts, trains and boats. The noise of an isolated sound event is assessed by the sound exposure level, LAE. Much legislation and many regulations and guidelines employ the A-weighted time-average sound level, LAeq,T, with the time interval T of one hour or longer. LAE measurements enable an approximation of LAeq,T. The key point is the uncertainty of this approximation. It has been shown that an increase in the number of LAE categories brings about a decrease in uncertainty. For illustrative purposes, LAE measurements of aircrafts taking off and landing were carried out.

An available bandwidth at a link is an unused capacity. Its measuring and/or estimation is not simple in practice. On the other hand, we know that its continuous knowledge is crucial for the operation of almost all networks. Therefore, there is a continuous effort in improving the existing and developing new methods of available bandwidth measurement and/or estimation. This paper deals with these problems. Network calculus terminology allows to express an available bandwidth in terms of a service curve. The service curve is a function representing a service available for a traffic flow which can be measured/estimated in a node as well as at an endto- end connection of a network. An Internet traffic is highly unpredictable what hinders to a large extent an execution of the tasks mentioned above. This paper draws attention to pitfalls and difficulties with application of the existing network calculus methods of an available bandwidth estimation in a real Internet Service Provider (ISP) network. The results achieved in measurements have been also confirmed in simulations performed as well as by mathematical considerations presented here. They give a new perspective on the outcomes obtained by other authors and on their interpretations.

A layered sensor structure of metal-free phthalocyanine H2Pc (~160 nm) with a very thin film of palladium (Pd ~20 nm) on the top, has been studied for hydrogen gas-sensing application at relatively low temperatures of about 30°C and about 40°C. The layered structure was obtained by vacuum deposition (first the phthalocyanine Pc and than the Pd film) onto a LiNbO3Y- cut Z-propagating substrate, making use of the Surface Acoustic Wave method, and additionally (in this same technological processes) onto a glass substrate with a planar microelectrode array for simultaneous monitoring of the planar resistance of the layered structure. In such a layered structure we can detect hydrogen in a medium concentration range (from 0.5 to 3% in air) even at about 30°C. At elevated temperature up to about 40°C the differential frequency increases proportionally (almost linearly) to the hydrogen concentration and the response reaches its steady state very quickly. The response times are about 18 s at the lowest 0.5% hydrogen concentration to about 42 s at 4% (defined as reaching 100% of the steady state). In the case of the investigated layered structure a very good correlation has been observed between the two utilized methods - the frequency changes in the SAW method correlate quite well with the decreases of the layered structure resistance.