International Journal of Electronics and Telecommunications

Arriving at a good combination of coding and modulation schemes that can achieve good error correction constitutes a challenge in digital communication systems. In this work, we explore the combination of permutation coding (PC) and pulse amplitude modulation (PAM) for mitigating channel errors in the presence of background noise and jitter. Since PAM is characterised with bi-polar constellations, Euclidean distance is a good choice for predicting the performance of such coded modulation setup. In order to address certain challenges facing PCs, we therefore introduce injections in the coding system, together with a modified form of PAM system. This modification entails constraining the PAM constellations to the size of the codeword’s symbol. The results obtained demonstrate the strength of the modified coded PAM system over the conventional PC coded PAM system.

Access logs may offer service providers a lot of information about specific users. Depending on the type of the service offers, the operator is capable of obtaining the user’s IP, location, communication habits, device information and so on. In this paper, we analyze a sample instant messenger service that is operating for a certain period of time. In our sandbox, we gathered enough data to correlate user communication habits with their localization, and even contacts. We show how seriously metadata may impact the user’s privacy and make some recommendations about mitigating the quantity of data collected in connection with this type of services.

The information technologies for assessing the quality of IT-specialties graduates' training of university by means of fuzzy logic and neural networks are developed in the article. It makes possible taking into account a wide set of estimation and output parameters, influence of the external and internal factors and allows to simplify the assessing process by means of modern mathematical apparatuses of artificial intelligence.

The concept of innovative educational environment of higher education establishment is considered and its main components are highlighted. The model of the integrated assessment of implementing innovations in higher education establishment is constructed. The developed model for assessing the level of development of the innovative educational environment of a specific higher education establishment during a certain period has been applied and a graphical analysis of the calculation results has been carried out.

As the delivery of good quality software in time is a very important part of the software development process, it's a very important task to organize this process very accurately. For this, a new method of the searching associative rules were proposed. It is based on the classification of all tasks on three different groups, depending on their difficulty, and after this, searching associative rules among them, which will help to define the time necessary to perform a specific task by the specific developer.

The concept of a hybrid scheme with connection of SIDH and ECDH is nowadays very popular. In hardware implementations it is convenient to use a classical key exchange algorithm, which is based on the same finite field as SIDH. Most frequently used hybrid scheme is SIDH-ECDH. On the other hand, using the same field as in SIDH, one can construct schemes over Fpn, like Diffie-Hellman or XTR scheme, whose security is based on the discrete logarithm problem. In this paper, idea of such schemes will be presented. The security of schemes, which are based on the discrete logarithm problem over fields Fp; Fp2 ; Fp4 ; Fp6 and Fp8 , for primes p used in SIDH, will be analyzed. At the end, the propositions of practical applications of these schemes will be presented.

A desirable property of iterated cryptographic algorithms, such as stream ciphers or pseudo-random generators, is the lack of short cycles. Many of the previously mentioned algorithms are based on the use of linear feedback shift registers (LFSR) and nonlinear feedback shift registers (NLFSR) and their combination. It is currently known how to construct LFSR to generate a bit sequence with a maximum period, but there is no such knowledge in the case of NLFSR. The latter would be useful in cryptography application (to have a few taps and relatively low algebraic degree). In this article, we propose a simple method based on the generation of algebraic equations to describe iterated cryptographic algorithms and find their solutions using an SAT solver to exclude short cycles in algorithms such as stream ciphers or nonlinear feedback shift register (NLFSR). Thanks to the use of AIG graphs, it is also possible to fully automate our algorithm, and the results of its operation are comparable to the results obtained by manual generation of equations. We present also the results of experiments in which we successfully found short cycles in the NLFSRs used in Grain-80, Grain-128 and Grain-128a stream ciphers and also in stream ciphers Bivium and Trivium (without constants used in the initialization step).

We discuss the challenge of achieving an auditable key management for cryptographic access control to high-value sensitive data. In such settings it is important to be able to audit the key management process - and in particular to be able to provide verifiable proofs of key generation. The auditable key management has several possible use cases in both civilian and military world. In particular, the new regulations for protection of sensitive personal data, such as GDPR, introduce strict requirements for handling of personal data and apply a very restrictive definition of what can be considered a personal data. Cryptographic access control for personal data has a potential to become extremely important for preserving industrial ability to innovate, while protecting subject’s privacy, especially in the context of widely deployed modern monitoring, tracking and profiling capabilities, that are used by both governmental institutions and high-tech companies. However, in general, an encrypted data is still considered as personal under GDPR and therefore cannot be, e.g., stored or processed in a public cloud or distributed ledger. In our work we propose an identity-based cryptographic framework that ensures confidentiality, availability, integrity of data while potentially remaining compliant with the GDPR framework.

Daniel Bernstein and Tanja Lange [9] proved that two given addition formulas on twisted Edwards elliptic curves ax2 +y2 = 1+dxy are complete (i.e. the sum of any two points on a curve can be computed using one of these formulas). In this paper we give simple verification of completeness of these formulas using a program written in Magma, which is based on the fact that completeness means that some systems of polynomial equations have no solutions. This method may also be useful to verify completeness of additions formulas on other models of elliptic curves.

This article presents methods and algorithms for the computation of isogenies of degree ℓn. Some of these methods are obtained using recurrence equations and generating functions. A standard multiplication based algorithm for computation of isogeny of degree ℓn has time complexity equal to O(n2 M (n log n)), where M(N) denotes the cost of integers of size N multiplication. The memory complexity of this algorithm is equal to O (n log (n log (n))). In this article are presented algorithms for:

• determination of optimal strategy for computation of degree ℓn isogeny,
• determination of cost of optimal strategy of computation of ℓn isogeny using solutions of recurrence equations,
• determination of cost of optimal strategy of computation of ℓn isogeny using recurrence equations,

where optimality in this context means that, for the given parameters, no other strategy exists that requires fewer operations for computation of isogeny.

Also this article presents a method using generating functions for obtaining the solutions of sequences (um) and (cm) where cm denotes the cost of computations of isogeny of degree ℓum for given costs p; q of ℓ-isogeny computation and ℓ-isogeny evaluation. These solutions are also used in the construction of the algorithms presented in this article.

In this paper we present a family of transforms that map existentially unforgeable signature schemes to signature schemes being strongly unforgeable. In spite of rising security, the transforms let us make a signature on a union of messages at once. The number of elements in this union depends on the signing algorithm of a scheme being transformed. In addition to that we define an existentially unforgeable signature scheme based on pairings, which satisfies all assumptions of the first part and is able to be subjected to transformation.

Signal attenuation caused by the propagation path between the compromising emanation source (the location of secured IT equipment) and the location of the antenna of the potential infiltrating system has a direct influence on the electromagnetic safety of IT equipment. The article presents original analytical relationships necessary to estimate the attenuation values introduced by the propagation path of the potential compromising emanation signal, which correspond to the most probable locations of IT equipment in relation to the location of the potential infiltrating system. The author of the article analyzes various location scenarios for IT equipment – a potential source of compromising emanations – with a potential infiltrating system located either within or outside the boundaries of a building, in which said IT equipment is located. The aforementioned scenarios are characterized by the lowest propagation path attenuation of potential compromising emanation generated by the secured IT equipment and provide for location masking of the potential infiltrating system. Example design of protective solutions for IT equipment elaborated by article author in the form of a shielding enclosure is presented in the article as well.

In this article is revealed the systems of a good delivery witch implement unmanned aerial vehicles during providing the service. the one channel systems of a goods delivery are a goal of this research work. the close analysing of their functional features, the classification, the types and parameters of different systems from this band are presented. in addition, the modelling of the different types of the one channel systems of goods delivery are has done.

An article herein presents an optimization model, designated for computational core of decision-taking support system (DTSS). DTSS is necessary for system analysis and search of optimal versions for cyber security facilities placement and information protection of an enterprise or organization distributed computational network (DCN). DTSS and a model allow automize the analysis of information protection and cyber security systems in different versions. It is possible to consider, how separate elements, influence at DCN protection factors and their combinations. Offered model, in distinction from existing, has allowed implementing both the principles of information protection equivalency to a concrete threat and a system complex approach to forming a highly effective protection system for DCN. Hereby we have presented the outcomes of computational experiments on selecting the rational program algorithm of implementing the developed optimization model. It has been offered to use genetic algorithm modification (GAM). Based on the offered model, there has been implemented the module for adaptive DTSS. DTSS module might be applied upon designing protected DCN, based on preset architecture and available sets of information protection and cyber security systems in the network.

This paper introduces security assessment methodology for isolated single-workstation multilayer systems processing sensitive or classified data according with a corresponding security model for such system. The document provides a high-level tool for systematizing certain-class-systems security models development. The models based on the introduced methodology cover data confidentiality and availability attributes protection on a sufficient level.

In this paper, we continue a topic of modeling measuring processes by perceiving them as a kind of signal sampling. And, in this respect, note that an ideal model was developed in a previous work. Whereas here, we present its nonideal version. This extended model takes into account an effect, which is called averaging of a measured signal. And, we show here that it is similar to smearing of signal samples arising in nonideal signal sampling. Furthermore, we demonstrate in this paper that signal averaging and signal smearing mean principally the same, under the conditions given. So, they can be modeled in the same way. A thorough analysis of errors related to the signal averaging in a measuring process is given and illustrated with equivalent schemes of the relationships derived. Furthermore, the results obtained are compared with the corresponding ones that were achieved analyzing amplitude quantization effects of sampled signals used in digital techniques. Also, we show here that modeling of errors related to signal averaging through the so-called quantization noise, assumed to be a uniform distributed random signal, is rather a bad choice. In this paper, an upper bound for the above error is derived. Moreover, conditions for occurrence of hidden aliasing effects in a measured signal are given.

In direct-detection OFDM systems, the nonlinear effects caused by optical modulation and fiber transmission can degrade the system performance severely. In this study, we propose a new nonlinear companding transform to improve the performance of direct detection optical OFDM transmission systems. The demonstration is realized by Monte-Carlo simulation of the intensity modulation and direct detection DCOOFDM optical transmission system at 40 Gbps over a 80 km of standard single mode fiber link. The influence of the companding parameters on the performance of system in different nonlinear transmission conditions has been investigated via simulation.

This paper details a hardware implementation of a distributed Θ(1) time algorithm allows to select dynamically the master device in ad-hoc or cluster-based networks in a constant time regardless the number of devices in the same cluster. The algorithm allows each device to automatically detect its own status; master or slave; based on identifier without adding extra overheads or exchanging packets that slow down the network. We propose a baseband design that implements algorithm functions and we detail the hardware implementation using Matlab/Simulink and Ettus B210 USRP. Tests held in laboratory prove that algorithm works as expected.

With the advent of massive MIMO and mmWave, Antenna selection is the new frontier in hybrid beamforming employed in 5G base stations. Tele-operators are reworking on the components while upgrading to 5G where the antenna is a last-mile device. The burden on the physical layer not only demands smart and adaptive antennas but also an intelligent antenna selection mechanism to reduce power consumption and improve system capacity while degrading the hardware cost and complexity. This work focuses on reducing the power consumption and finding the optimal number of RF chains for a given millimeter wave massive MIMO system. At first, we investigate the power scaling method for both perfect Channel State Information (CSI) and imperfect CSI where the power is reduced by ��/���� and ��/√���� respectively. We further propose to reduce the power consumption by emphasizing on the subdued resolution of Analog-to-Digital Converters (ADCs) with quantization awareness. The proposed algorithm selects the optimal number of antenna elements based on the resolution of ADCs without compromising on the quality of reception. The performance of the proposed algorithm shows significant improvement when compared with conventional and random antenna selection methods.

The subject of the article is the design and practical implementation of the wireless mesh network. IQRF radio modules were used for the network design. The IQRF® technique has enabled the construction of a mesh network with the possibility of reconfiguration. The theoretical part contains a description of the IQRF® hardware solutions used. The practical scope includes the design part, where the configuration of the radio modules was carried out and the parameters of the radio network were set to allow its implementation in various topologies. Then, a wireless network consisting of 10 IQRF modules was launched in the P3 building of the Opole University of Technology. At this stage, configured radio modules were placed in selected rooms on all five floors of the building in order to carry out tests of the radio network constructed in this way. The tests included measuring the packet transmission delay time as well as the received signal strength. Research was carried out for several network topologies.

This paper presents the design of a compact protocol for fixed-latency, high-speed, reliable, serial transmission between simple field-programmable gate arrays (FPGA) devices. Implementation of the project aims to delineate word boundaries, provide randomness to the electromagnetic interference (EMI) generated by the electrical transitions, allow for clock recovery and maintain direct current (DC) balance. An orthogonal concatenated coding scheme is used for correcting transmission errors using modified Bose–Chaudhuri–Hocquenghem (BCH) code capable of correcting all single bit errors and most of the double-adjacent errors. As a result all burst errors of a length up to 31 bits, and some of the longer group errors, are corrected within 256 bits long packet. The efficiency of the proposed solution equals 46.48%, as 119 out of 256 bits are fully available to the user. The design has been implemented and tested on Xilinx Kintex UltraScale+ KCU116 Evaluation Kit with a data rate of 28.2 Gbps. Sample latency analysis has also been performed so that user could easily carry out calculations for different transmission speed. The main advancement of the work is the use of modified BCH(15, 11) code that leads to high error correction capabilities for burst errors and user friendly packet length.

DC-DC converters are popular switch-mode electronic circuits used in power supply systems of many electronic devices. Designing such converters requires reliable computation methods and models of components contained in these converters, allowing for accurate and fast computations of their characteristics. In the paper, a new averaged model of a diodetransistor switch containing an IGBT is proposed. The form of the developed model is presented. Its accuracy is verified by comparing the computed characteristics of the boost converter with the characteristics computed in SPICE using a transient analysis and literature models of a diode and an IGBT. The obtained results of computations proved the usefulness of the proposed model.

The copy-move forgery detection (CMFD) begins with the preprocessing until the image is ready to process. Then, the image features are extracted using a feature-transform-based extraction called the scale-invariant feature transform (SIFT). The last step is features matching using Generalized 2 Nearest- Neighbor (G2NN) method with threshold values variation. The problem is what is the optimal threshold value and number of keypoints so that copy-move detection has the highest accuracy. The optimal threshold value and number of keypoints had determined so that the detection has the highest accuracy. The research was carried out on images without noise and with Gaussian noise.

The continuous growth of smart communities and ever-increasing demand of sending or storing videos, have led to consumption of huge amount of data. The video compression techniques are solving this emerging challenge. However, H.264 standard can be considered most notable, and it has proven to meet problematic requirements. The authors present (BPMM) as a novel efficient Intra prediction scheme. We can say that the creation of our proposed technique was in a phased manner; it's emerged as a proposal and achieved impressive results in the performance parameters as compression ratios, bit rates, and PSNR. Then in the second stage, we solved the challenges of overcoming the obstacle of encoding bits overhead. In this research, we try to address the final phase of the (BPMM) codec and to introduce our approach in a global manner through realization of decoding mechanism. For evaluation of our scheme, we utilized VHDL as a platform. Final results have proven our success to pass bottleneck of this phase, since the decoded videos have the same PSNR that our encoder tells us, while preserving steady compression ratio treating the overhead. We aspire our BPMM algorithm will be adopted as reference design of H.264 in the ITU.

Hereby there is given the speaker identification basic system. There is discussed application and usage of the voice interfaces, in particular, speaker voice identification upon robot and human being communication. There is given description of the information system for speaker automatic identification according to the voice to apply to robotic-verbal systems. There is carried out review of algorithms and computer-aided learning libraries and selected the most appropriate, according to the necessary criteria, ALGLIB. There is conducted the research of identification model operation performance assessment at different set of the fundamental voice tone. As the criterion of accuracy there has been used the percentage of improperly classified cases of a speaker identification.

In this paper, we show that signal sampling operation can be considered as a kind of all-pass filtering in the time domain, when the Nyquist frequency is larger or equal to the maximal frequency in the spectrum of a signal sampled. We demonstrate that this seemingly obvious observation has wideranging implications. They are discussed here in detail. Furthermore, we discuss also signal shaping effects that occur in the case of signal under-sampling. That is, when the Nyquist frequency is smaller than the maximal frequency in the spectrum of a signal sampled. Further, we explain the mechanism of a specific signal distortion that arises under these circumstances. We call it the signal shaping, not the signal aliasing, because of many reasons discussed throughout this paper. Mainly however because of the fact that the operation behind it, called also the signal shaping here, is not a filtering in a usual sense. And, it is shown that this kind of shaping depends upon the sampling phase. Furthermore, formulated in other words, this operation can be viewed as a one which shapes the signal and performs the low-pass filtering of it at the same time. Also, an interesting relation connecting the Fourier transform of a signal filtered with the use of an ideal low-pass filter having the cut frequency lying in the region of under-sampling with the Fourier transforms of its two under-sampled versions is derived. This relation is presented in the time domain, too.