Synthesis of Quite Proof Cryptosystem with Increased Unicity Distance for Cloud Computing

Modern cryptosystems have a narrow application area, mainly because of a strict restriction of overrunning during the encryption of so-called unicity distance for the key. It is possible to essentially increase the unicity distance by using a synthesis of a constructed/artificial/planned language in the application area, where an alphabet of a high dimension is used. There was made a synthesis of highly secured cryptosystem. It has such feature as the security of text information with an increased unicity distance. This distance is set into a tabular form which assumes that this text information is taken from the thesaurus of predefined application area. There were gotten mathematical expressions that display the procedure of the encryption and decryption. There were considered the features of construction of the generator of pseudorandom sequences. Also, there was defined the level of security of cryptosystem with a different levels of resource capabilities. There was given a graph of correlation between the indicator of security and the code length of the encryption key. There were also defined the conditions of providing a necessary security regime in cloud systems

Mechanisms of Charge Transport and Photoelectric Conversion in CdTe-Based X- and Gamma-Ray Detectors

This chapter deals with (i) the charge transport mechanisms in X- and gamma-ray detectors both Ohmic and Schottky types based on CdTe and its alloys with an almost intrinsic conductivity (the peculiarities of the formation of self-compensated complexes due to the doping of Cd(Zn)Te crystals with elements of III or V groups (In, Cl) are taken into account); (ii) the reasons of insufficient energy resolution in the X- and gamma-ray spectra taken with the detectors under study; (iii) the quantitative model which describes the spectral distribution of the detection efficiency of Cd(Zn)Te crystals with Schottky diodes; (iv) a correlation between the concentration of uncompensated impurities in the Cd(Zn)Te crystals and collection efficiency of photogenerated charge carriers in the detectors with a Schottky contact; (v) the possibility of applications of CdTe thin films with a Schottky contact as an alternative to the existing X-rays image detectors based on a-Se

Chapter Mechanisms of Charge Transport and Photoelectric Conversion in CdTe-Based X- and Gamma-Ray Detectors

This chapter deals with (i) the charge transport mechanisms in X- and gamma-ray detectors both Ohmic and Schottky types based on CdTe and its alloys with an almost intrinsic conductivity (the peculiarities of the formation of self-compensated complexes due to the doping of Cd(Zn)Te crystals with elements of III or V groups (In, Cl) are taken into account); (ii) the reasons of insufficient energy resolution in the X- and gamma-ray spectra taken with the detectors under study; (iii) the quantitative model which describes the spectral distribution of the detection efficiency of Cd(Zn)Te crystals with Schottky diodes; (iv) a correlation between the concentration of uncompensated impurities in the Cd(Zn)Te crystals and collection efficiency of photogenerated charge carriers in the detectors with a Schottky contact; (v) the possibility of applications of CdTe thin films with a Schottky contact as an alternative to the existing X-rays image detectors based on a-Se

Mathematical Model for Adaptive Technology in E-learning Systems

The emergence of a large number of e-learning platforms and courses does not solve the problem of improving the quality of education. This is primarily due to insufficient implementation or lack of mechanisms for adaptation to the individual parameters of the student. The level of adaptation in modern e-learning systems to the individual characteristics of the student makes the organization of human-computer interaction relevant. As the solution of the problem, a mathematical model of the organization of human-computer interaction was proposed in this work. It is based on the principle of two-level adaptation that determines the choice of the most comfortable module for studying at the first level. The formation of an individual learning path is performed at the second level. The problem of choosing an e-module is solved using a fuzzy logic. The problem of forming a learning path is reduced to the problem of linear programming. The input data are the characteristics of the quality of student activity in the education system. Based on the proposed model the computer technology to support student activities in modular e-learning systems is developed. This technology allows increasing the level of student’s cognitive comfort and optimizing the learning time. The most important benefit of the proposed approach is to increase the average score and increase student satisfaction with learning

CDTE X/Γ-RAY DETECTORS WITH DIFFERENT CONTACT MATERIALS

Different contact materials and optimization of techniques of their depositions expand the possibilities to obtain high performance room temperature CdTe-based X/γ-ray detectors. The heterostructures with ohmic (MoOx) and Schottky (MoOx, TiOx, TiN, and In) contacts, created by DC reactive magnetron sputtering and vacuum thermal evaporation, as well as In/CdTe/Au diodes with a p-n junction, formed by laser-induced doping, have been developed and investigated. De-pending on the surface pre-treatment of semi-insulating p-CdTe crystals, the deposition of a MoOx film formed either ohmic or Schottky contacts. Based on the calculations and I-V characteristics of the Mo-MoOx/р-CdTe/MoOx-Mo, In/р-CdTe/MoOx-Mo, Ti-TiOx/р-CdTe/MoOx-Mo, and Ti-TiN/р-CdTe/MoOx-Mo Schottky-diode detectors, the current transport processes were described in the models of the carrier generation–recombination within the space-charge region (SCR) at low bias, and space-charge limited current incorporating the Poole–Frenkel effect at higher voltages, respectively. The energies of generation–recombination centers, density of trapping centers, and effective carrier lifetimes were determined. Nanosecond laser irradiation of the In electrode, pre-deposited on the p-CdTe crystals, resulted in extending the voltage range, corresponding to the carrier generation–recombination in the SCR in the I-V characteristics of the In/CdTe/Au diodes. Such In/CdTe/Au p-n junction diode detectors demonstrated high energy resolutions (7%@59.5 keV, 4%@122 keV, and 1.6%@662 keV)

Mechanism of Nanostructure Formation on a Surface of CdZnTe Crystal by Laser Irradiation

Self-organizing nanometer size structures are observed on the surface of CdZnTe crystal irradiated by strongly absorbed Nd:YAG laser irradiation (LR) at intensity range of 4-12 MW/cm . According to this model the Thermogra- dient effect has the main role in the interaction process of LR and semiconductors. The surface state of the CdZnTe under the influence of Nd:YAG laser irradiation has been studied. A state has been defined by atom force microsco- pe. The influence of LR on the photoluminescence spectra has show that at a threshold intensity of LR I=4MW/cm creation of nanometer size structure begins. A graded band gap structure with optical window was formed at the top of nano-hills

Multilevel data model for requirements providing identification accordingly to regulatory support for civil aviation cybersecurity

Захист критичної інфраструктури на сьогодні є одним із першочергових завдань держави, особливо гостро це питання постає перед державами, які впроваджують новітні інформаційно-комунікаційні технології в усіх критичних галузях. Зазначені технології, крім іншого, породжують цілу низку нових уразливостей та потенційних кіберзагроз. У галузі цивільної авіації рівень критичності значно підсилюється комунікацією та взаємодією між наземними системами і повітряними суднами. Відома модель формування вимог до забезпечення кібербезпеки цивільної авіації дозволяє форма- лізувати процес створення повної множини вимог, які необхідно забезпечити для захисту цивільної авіації від кіберзагроз, проте відсутній механізм визначення забезпеченості певних режимів безпеки внаслідок реалізації методів та засобів, задекларованих у відповідних вимогах. З огляду на це, актуальною є розробка підходу до визначення забезпеченості режимів безпеки, що враховуватимуть додаткові характеристики безпеки. У цій роботі запропоновано мультирівневу модель даних, яка за рахунок використання базової моделі формування вимог до забезпечення кібербезпеки цивільної авіації, конкатенації бінарних послідовностей, що характеризують режими безпеки, та бінарно-шістнадцяткового кодового представлення характеристик безпеки, множини моделей безпеки та підмножин характеристик безпеки (з урахуванням додаткових характеристик), дозволяє формалізувати процес ідентифікації забезпеченості вимог та визначення режимів безпеки критичних авіаційних інформаційних систем. У подальших дослідженнях планується розробити метод оцінювання повноти забезпечення вимог у результаті реалізації відповідних методів та засобів захисту