Abstract. QoS-aware service composition is a key requirement in Service Oriented Computing (SOC) since it enables fulfilling complex user tasks while meeting Quality of Service (QoS) constraints. A challenging issue towards this purpose is the selection of the best set of services to compose, meeting global QoS constraints imposed by the user, which is known to be a NP-hard problem. This challenge becomes even more relevant when it is considered in the context of dynamic service environments. Indeed, two specific issues arise. First, required tasks are fulfilled on the fly, thus the time available for services' selection and composition is limited. Second, service compositions have to be adaptive so that they can cope with changing conditions of the environment. In this paper, we present an efficient service selection algorithm that provides the appropriate ground for QoS-aware composition in dynamic service environments. Our algorithm is formed as a guided heuristic. The paper also presents a set of experiments conducted to evaluate the efficiency of our algorithm, which shows its timeliness and optimality.

Antiradical potential (ARP) is an important measure of food safety. In addition, it directly or indirectly affects the rate of occurrence of a number of human pathologies. Using a photocolorimetric analysis of DPPH (2,2-diphenyl-1-picrylhydrazyl) solutions, we estimated the antiradical potential of food raw materials, food concentrates, biologically active substances, and wild plants. We conducted approximately 1500 analyses of almost 100 food products selected from 11 food groups: vegetables, milk, meat, fish, cereals and bread, drinks (including tea and coffee), etc. With a confidence interval (CI) of 95%, the average values for animal products range from 15.87 to 18.70 ascorbic acid equivalents per gram of dry matter. For plant materials, the range is 474.54–501.50 equivalents when wild herbs are included and 385.02–408.83 equivalents without taking herbs into account. The antiradical potential of the biologically active substances we studied ranged from 706.84 to 847.77 equivalents per gram of dry matter, which makes it possible to use some of the components to repair products with low ARP values, for example, bread and baked goods, confectionery, milk and dairy products, carbonated drinks, and juice. In this study, a low ARP value is associated with a reduction in the shelf life of products and a deterioration in their organoleptic properties; therefore, we propose using ARP as an important reference for describing the quality of food products and raw food materials.

The article analyses the relative position of the Russian teachers from higher education institutions in professional labor market in transition. The specificity of teachers' situation in the labor market is revealed in conditions of shift from administrative command system to market relations. There are some distinguished factors that increase the risk of job loss by teachers of different categories. The characteristics of main forms and types of "professorate" unemployment in modern stage are discussed. Based on the results of sociological survey, the relation of teachers to the market economy is analyzed and an attempt is made to find out the way which can stabilize teachers' professional position at the time when new educational policies are being implemented in order to optimize the field of higher education.

The article discusses the economic issues of biodiesel use in agricultural production. Study purpose: determination of the biodiesel production basic economic parameters for agricultural needs. Costs of biodiesel production, formation when using different crops, and costs of replacing traditional diesel fuel are calculated based on an example of a specific enterprise. To solve the problem posed in the study, used specialized software for calculating technological maps in crop production. As a result of the study, it was determined that the own production of biodiesel in the agricultural enterprise conditions is economically justified even at an oil prices low world level. Thanks to the implementation of the investment project to create biodiesel production, it is possible to reduce the cost of fuel and lubricants and thus increase production efficiency. Every year in the conditions of the economy from the use of biodiesel, an economic effect of 2358.7 thousand rubles can be reached.

Russia is an agrarian country, the significant part of territory is rural areas with a population living on them. It is well known that in many important respects they are highly differentiated from cities: lower incomes, availability of services and opportunities for self-realization. Currently, the formation of a high-quality and comfortable working and living environment in rural areas is nationally important. The relevance of this study is explained by the need to form an evaluation system of compliance the level of socio-economic development of rural areas to modern standards of living. The article presents the author's approaches to solving the indicated problem. Improving the availability and quality of socially important services is a necessary condition for increasing the level of rural life. To solve this problem, it is proposed: 1) create a list of indicators to assess the quality of services received by the rural population; 2) assess the security and availability of services received in the village, including taking into account the territorial and financial possibilities of their consumption; 3) normalize the obtained system of indicators relative to the selected standard; 4) propose measures to improve the availability and accessibility of services in rural areas, as well as the mechanism of their implementation. To assess the average complex of needs for services, a system of indicators used by state and municipal authorities is allocated. The data of calculation of indicators characterizing the provision of services in homogeneous and heterogeneous rural municipal areas of the Voronezh region are presented.