РІВНІ ТА НАПРЯМИ ДІЯЛЬНОСТІ ПРАВООХОРОННИХ ОРГАНІВ ІЗ ЗАБЕЗПЕЧЕННЯ ФІНАНСОВО-ЕКОНОМІЧНОЇ БЕЗПЕКИ ДЕРЖАВИ

The National Anti-Corruption Bureau of Ukraine, the agencies of the National Police of Ukraine and the Security Service of Ukraine, units of the tax police of the State Fiscal Service of Ukraine are assigned to law enforcement agencies to ensure financial and economic security of the state. It has been stressed that the necessity of studying the levels and directions of the activity of law enforcement agencies in the sphere of providing financial and economic security of Ukraine is caused by the current state of protection of financial and economic interests of the state against unlawful encroachments. It has been concluded that law enforcement agencies in the field of ensuring financial and economic security of the state carry out their activities in two directions: strategic, aimed at preventing financial and economic crime in the state; tactical, the main purpose of which is to directly detect, terminate and investigate already committed socially dangerous acts that encroach on the financial and economic interests of the state. It has been also clarified that, along with the activities of law enforcement agencies in the field of ensuring financial and economic security of the state, the levels of their activities are important. In this regard, the author has substantiated the existence of three levels of activity of law enforcement agencies on ensuring financial and economic security of the state – international, national and regional.Обґрунтовано наявність двох напрямів діяльності правоохоронних органів у сфері забезпечення фінансово-економічної безпеки держави – стратегічного і тактичного. З’ясовано, що поряд із напрямами важливе значення мають також рівні їх діяльності. У зв’язку з цим обґрунтовано існування трьох рівнів діяльності правоохоронних органів у сфері забезпечення фінансово-економічної безпеки держави – міжнародного, загальнодержавного та регіонального

Generation of optical frequency combs in fibres

We numerically investigated the possibility of generating high-quality ultra-short optical pulses with broad frequencycombs spectra in a system consisting of three optical fibres. In this system, the first fibre is a conventional single-mode fibre, the second one is erbium-doped, and the last one is a low-dispersion fibre. The system is pumped with a modulated sine-wave generated by two equally intense lasers with the wavelengths λ ;1and λ2 such that their central wavelength is at λc = (λ1 + λ2)/2 = 1531 nm. The modelling was performed using the generalised nonlinear Schrödinger equation which includes the Kerr and Raman effects, as well as the higher-order dispersion and gain. We took a close look at the pulse evolution in the first two stages and studied the pulse behaviour depending on the group-velocity dispersion and the nonlinear parameter of first fibre, as well as the initial laser frequency separation. For these parameters, the optimum lengths of fibre 1 and 2 were found that provide low-noise pulses. To characterise the pulse energy content, we introduced a figure of merit that was dependent on the group-velocity dispersion, the nonlinearity of fibre 1, and the laser separation

Characteristics and stability of soliton crystals in optical fibres for the purpose of optical frequency comb generation

We study the properties of a soliton crystal, a bound state of several optical pulses that propagate with a fixed temporal separation through the optical fibres of the proposed approach for generation of optical frequency combs (OFC) for astronomical spectrograph calibration. This approach - also being suitable for subpicosecond pulse generation for other applications - consists of a conventional single-mode fibre and a suitably pumped Erbium-doped fibre. Two continuous-wave lasers are used as light source. The soliton crystal arises out of the initial deeply modulated laser field at low input powers; for higher input powers, it dissolves into free solitons. We study the soliton crystal build-up in the first fibre stage with respect to different fibre parameters (group-velocity dispersion, nonlinearity, and optical losses) and to the light source characteristics (laser frequency separation and intensity difference). We show that the soliton crystal can be described by two quantities, its fundamental frequency and the laser power-threshold at which the crystal dissolves into free solitons. The soliton crystal exhibits features of a linear and nonlinear optical pattern at the same time and is insensitive to the initial laser power fluctuations. We perform our studies using the numerical technique called Soliton Radiation Beat Analysis

Optimum integration procedures for supercontinuum simulation

We study numerical solutions of the generalized nonlinear Schro¨ dinger equation (GNLSE), focusing on the advantage of integrating the nonlinear part of the equation in the frequency domain (FD), rather than in the time domain (TD), when simulating supercontinuum generation in optical fibers. We show that integration of the nonlinear operator in the FD is more efficient than its integration in the TD. We analyze different adaptive stepsize algorithms in combination with the interaction picture integration method and show that their performance strongly depends on whether integration of the nonlinear operator is performed in the FD or TD. We find that the most efficient procedure for supercontinuum simulation in optical fibers results from solving the nonlinearity in the FD and applying the recently introduced conservation quantity error adaptive step-size algorithm.Fil: Rieznik, Andrés Anibal. Instituto Tecnológico de Buenos Aires. Departamento de Investigación y Doctorado; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Heidt, A. M.. University of Stellenbosch; Sudáfrica. Leibniz Institute of Photonic Technology; AlemaniaFil: König, Pablo Germán. Instituto Tecnológico de Buenos Aires. Departamento de Investigación y Doctorado; ArgentinaFil: Bettachini, Victor. Instituto Tecnológico de Buenos Aires. Departamento de Investigación y Doctorado; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Grosz, Diego Fernando. Instituto Tecnológico de Buenos Aires. Departamento de Investigación y Doctorado; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Generation of optical frequency combs in fibres:an optical pulse analysis

The innovation of optical frequency combs (OFCs) generated in passive mode-locked lasers has provided astronomy with unprecedented accuracy for wavelength calibration in high-resolution spectroscopy in research areas such as the discovery of exoplanets or the measurement of fundamental constants. The unique properties of OCFs, namely a highly dense spectrum of uniformly spaced emission lines of nearly equal intensity over the nominal wavelength range, is not only beneficial for high-resolution spectroscopy. Also in the low- to medium-resolution domain, the OFCs hold the promise to revolutionise the calibration techniques. Here, we present a novel method for generation of OFCs. As opposed to the mode-locked laser-based approach that can be complex, costly, and difficult to stabilise, we propose an all optical fibre-based system that is simple, compact, stable, and low-cost. Our system consists of three optical fibres where the first one is a conventional single-mode fibre, the second one is an erbium-doped fibre and the third one is a highly nonlinear low-dispersion fibre. The system is pumped by two equally intense continuous-wave (CW) lasers. To be able to control the quality and the bandwidth of the OFCs, it is crucial to understand how optical solitons arise out of the initial modulated CW field in the first fibre. Here, we numerically investigate the pulse evolution in the first fibre using the technique of the solitons radiation beat analysis. Having applied this technique, we realised that formation of higherorder solitons is supported in the low-energy region, whereas, in the high-energy region, Kuznetsov-Ma solitons appear

Soliton radiation beat analysis of optical pulses generated from two continuous-wave lasers

We propose a fibre-based approach for generation of optical frequency combs (OFCs) with the aim of calibration of astronomical spectrographs in the low and medium-resolution range. This approach includes two steps: in the first step, an appropriate state of optical pulses is generated and subsequently moulded in the second step delivering the desired OFC. More precisely, the first step is realised by injection of two continuous-wave (CW) lasers into a conventional single-mode fibre, whereas the second step generates a broad OFC by using the optical solitons generated in step one as initial condition. We investigate the conversion of a bichromatic input wave produced by two initial CW lasers into a train of optical solitons, which happens in the fibre used as step one. Especially, we are interested in the soliton content of the pulses created in this fibre. For that, we study different initial conditions (a single cosine-hump, an Akhmediev breather, and a deeply modulated bichromatic wave) by means of soliton radiation beat analysis and compare the results to draw conclusion about the soliton content of the state generated in the first step. In case of a deeply modulated bichromatic wave, we observed the formation of a collective soliton crystal for low input powers and the appearance of separated solitons for high input powers. An intermediate state showing the features of both, the soliton crystal and the separated solitons, turned out to be most suitable for the generation of OFC for the purpose of calibration of astronomical spectrographs

Tax on Cryptocurrency as Innovative Financial Instrument in IT Sphere

The article deals with the content of the tax on cryptocurrency, which is an innovative IT instrument of economic development. It has been established that there was no common understanding of the official status of cryptocurrency given that each state establishes it in the framework of its national legislation independently, and the introduction of taxes is one of the instruments of state influence on the cryptocurrency circulation. It has been found out that the EU member states had only one restriction on the taxation of cryptocurrency, namely cryptocurrency transactions were not liable for VAT. Foreign experience in taxing cryptocurrency transactions is considered in the article. It has been established that Ukraine offered the most optimal tax rate on income from cryptocurrency transactions for individuals and legal entities. At the same time, the significance of the economic effect of the cryptocurrency tax in the form of revenues to the state budget due to the unstable cryptocurrency exchange rate is disproved, which raises the issue of the feasibility of search for new areas of state influence on cryptocurrency