No abstract

Введение. Качество автоматизированной системы управления полетами космических аппаратов (АСУ КА) зависит от воздействия на нее различных факторов риска. Источники факторов риска (ИФР) являются отправным пунктом при разработке механизмов обеспече-ния требуемого качества системы [1][2][3][4][5][6][7][8]. Многочисленность факторов риска и источников их возникновения требует выделения из их пол-ного состава основных факторов, в значительной мере влияющих на информационную устойчивость АСУ КА. Одним из подходов к клас-сификации ИФР для АСУ КА является использование бинарных от-ношений и математического аппарата теорий множеств. Такой под-ход позволяет выделить множество факторов риска, обладающих свойствами полноты, непротиворечивости и неизбыточности, а также определить механизмы их обнаружения и нейтрализации.Классификация источников факторов риска АСУ КА. Опре-деление множества факторов риска для качества функционирования АСУ КА базируется на рассмотрении ее предметной области. Содер-жательное описание предметной области АСУ КА включает такие основные понятия, как структура системы, входная, промежуточная и выходная информация. Качество АСУ КА определяется на основе анализа факторов риска на всех этапах ее жизненного цикла.

Damage in the form of fatigue cracks can arise and corrosion processes can be initiated in the material of a structural element under prolonged simultaneous exposure to variable stresses of different nature. In this connection, it is necessary to construct an adequate mathematical model of the reliability that would make it possible to determine the lifespan of the structure during operation. Accurate values of the lifespan indicators of a part are impossible to obtain in the case of multidimensional loads. For this reason, it is of practical interest to obtain estimates of these indicators, which is the subject of discussion in this article.Damage in the form of fatigue cracks can appear and corrosion processes can be initiated in the material of a structural element under prolonged simultaneous action of variable stresses of different nature. These processes are irreversible, and ultimately result in failure of the element [1]. Thus, the pipelines in a nuclear power plant operate under simultaneous exposure to corrosive media, high pressure and temperature, pressure and temperature pulsations, liquid and vapor flows, radiation, mechanical impacts, and so forth [2]. In practice, most operating objects are subjected to several destructive factors. Thus, in most practical situations multidimensional cyclic loads act on a part.Since the character of each action of periodic loads on a part is random in general, it is desirable to use a stochastic approach to obtaining the lifespan indicators of a part operating under cyclic perturbations. In addition, the part itself is manufactured with a definite accuracy, which is also of a random nature. This makes it necessary to develop reliability-probabilistic computational methods which would be able to answer any questions concerning the lifespan of a system during operation.Accurate values describing the functioning of a system can be obtained only for certain distribution laws for an applied load, even in the case of one-dimensional perturbations [3]. In the case of multidimensional loads, accurate lifespan indicators cannot be obtained even for the simplest load distribution laws, so that it is of practical interest to estimate them. A method for obtaining the lower (pessimistic) estimate of the probability P(t, x) of failure-free operation under conditions of discrete degradation of a part is described in [5]; this method is based on inferences from the Hausdorff estimator [4]. In the present article this method is extended to the case where a multidimensional cyclic load acts on a part.Formulation of the Problem. Consider a part on which act n independent fluxes of periodic perturbations. Let the time intervals between adjacent load cycles of type i τ i1 , τ i2 , τ i3 , ..., τ ik be independent and have the same distribution function F i (t) = F ij (t) = P(τ ij ≤ t), i = 1, 2, 3, 4, ..., n and j = 1, 2, 3, ..., k, with the possible exception of F i1 (t) = P(τ i1 ≤ t) ≠ F i (t).Similarly, we shall assume that each perturbation of the type i changes the damage accumulat...

The quality of development and commissioning the automated system for preparing aircraft flight data (ASPD) depends on many factors, among which it is necessary to identify and justify those most significantly affecting quality of the system being commissioned. The practice of designing an ASPD has shown that the quality assessment based on its characteristics is nothing more than a consequence. This situation is due to the presence of deeper factors that will only appear during the operation of the system. To eliminate this situation, the problem is formulated as a task of determining the factors affecting the quality of development and commissioning the system, based on the data obtained by mathematical processing of expert estimates of each factor significance. To solve this problem, it is proposed to use the hierarchy analysis method. Developed on its basis the methodological approach makes it possible: – to identify the main factors significantly affecting the quality of the ASPD being commissioned, and to propose qualitative scales for assessing the degree of feasibility of each generic criterion; – to formalize a multi-criteria indicator of the degree of the ASPD quality compliance with the requirements of generic criteria and obtain its dependence on the levels of development and commissioning the system; – to justify the requirements for ASPD operational suitability, perform its evaluation, as well as determine the necessary measures for implementing the specified requirements on operational and technical characteristics of the ASPD.

Введение. Под стойкостью автоматизированной системы управ-ления полетами космических аппаратов (АСУП КА) понимается свойство системы выполнять свои функции и сохранять свои пара-метры в пределах установленных значений во время и после воздей-ствия на нее факторов риска [1] в течение всего срока службы в за-данных условиях эксплуатации.Цель оценки стойкости функций безопасности -выявление сте-пени устойчивости АСУП КА, выступающей объектом оценки, по отношению к атакам нарушителя с определенно низким, умеренным или высоким потенциалом нападения [2][3][4][5][6].