Определение оптимальных характеристик алгоритма конкурентного доступа к среде для минимизации времени передачи данных в децентрализованных беспроводных сетях
Provides an overview of the principles of organization of communication in decentralized wireless networks is reviewed. The scheme of the decentralized network and the timing diagram of data transfer between nodes are shown. Investigated the problem of ensuring the effectiveness of collaboration with a number of nodes in low-power networks and consider the possibility of using for this purpose a probabilistic network Protocol data-link layer. The analysis of the algorithm access to the environment in a decentralized network, presents its block diagram. Detail displayed blocks of the algorithm that determine when data transmission from the network node. Through computational experiments on a model of a decentralized network investigated of the dependence of the efficiency of the work of the algorithm access to the airwaves from such temporal characteristics as the delay before sending data and waiting period before attempting to send them. The most loaded time point identified in the network exchange. It is shown that the developed computer program allow to calculate the probable collisions in the air. Suggested hardware implementation of the algorithm based on microcontroller STM32F030F4P6 of ST Microelectronics and transceiver CC1101 of Texas Instruments.
The principles of communication in decentralized networks is reviewed. A desk review of existing methods of access to the airwaves in the nodes of the network and identifies their shortcomings related to electromagnetic compatibility. A way to exchange data with the priorities is proposed. The experiment results of the network is shown.
This research provides the strategy of using two modern directions such as Big Data and Internet of Things and their various opportunities. There are the overview and analysis of tools which helps to work in this area: cloud services for data’s storage and its monitoring. The new using option, linking technologies Big Data and Internet of Things, is represented in this work.
This article contains analysis of properties discrete electron-wave interaction in resonance slow-wave system (SWS). Equations of interaction are written in matrix form. Eigenvalues of transfer matrix with electron beam define spread constant of four electron waves. Features of electron waves in SWS with «smooth» energy stream and in SWS with «winding» flow are examined. Simulation is performed and amplification of multi-section TWT with passband and stopband sections of SWS is found. Field distribution along stopband section is found.
This book constitutes the refereed proceedings of the 5th International Workshop on Multiple Access Communications, MACOM 2012, held in Maynooth, Ireland, in November 2012. The 13 full papers and 5 demo and poster papers presented were carefully reviewed and selected from various submissions. The papers are organized in topical sections on network coding, handling interference and localization techniques at PHY/MAC layers, wireless access networks, and medium access control.
Video broadcasts on the Internet have become a commonplace and increasingly find their audience, supported by popular video services and social networks. But there are tasks, that require content delivery network (CDN), which lead to extra expences, and moreover, does not give sufficient flexibility and limits personalization of the broadcasts. This paper presents the principles of creating a flexible and scalable streaming content delivery network, created automatically for each individual broadcast over existing infrastructure of the cloud virtual machine hosting providers. The report originates from a commercial project dedicated to creation of media-content delivery network, currently being at development stage.
Educational laboratory complex "Microprocessors" is designed for familiarization of students of high technical educational institutions with basics of microprocessor technique and opportunity of using of microcontrollers in modern instrumentation.
A model for organizing cargo transportation between two node stations connected by a railway line which contains a certain number of intermediate stations is considered. The movement of cargo is in one direction. Such a situation may occur, for example, if one of the node stations is located in a region which produce raw material for manufacturing industry located in another region, and there is another node station. The organization of freight traﬃc is performed by means of a number of technologies. These technologies determine the rules for taking on cargo at the initial node station, the rules of interaction between neighboring stations, as well as the rule of distribution of cargo to the ﬁnal node stations. The process of cargo transportation is followed by the set rule of control. For such a model, one must determine possible modes of cargo transportation and describe their properties. This model is described by a ﬁnite-dimensional system of diﬀerential equations with nonlocal linear restrictions. The class of the solution satisfying nonlocal linear restrictions is extremely narrow. It results in the need for the “correct” extension of solutions of a system of diﬀerential equations to a class of quasi-solutions having the distinctive feature of gaps in a countable number of points. It was possible numerically using the Runge–Kutta method of the fourth order to build these quasi-solutions and determine their rate of growth. Let us note that in the technical plan the main complexity consisted in obtaining quasi-solutions satisfying the nonlocal linear restrictions. Furthermore, we investigated the dependence of quasi-solutions and, in particular, sizes of gaps (jumps) of solutions on a number of parameters of the model characterizing a rule of control, technologies for transportation of cargo and intensity of giving of cargo on a node station.
Event logs collected by modern information and technical systems usually contain enough data for automated process models discovery. A variety of algorithms was developed for process models discovery, conformance checking, log to model alignment, comparison of process models, etc., nevertheless a quick analysis of ad-hoc selected parts of a journal still have not get a full-fledged implementation. This paper describes an ROLAP-based method of multidimensional event logs storage for process mining. The result of the analysis of the journal is visualized as directed graph representing the union of all possible event sequences, ranked by their occurrence probability. Our implementation allows the analyst to discover process models for sublogs defined by ad-hoc selection of criteria and value of occurrence probability
The geographic information system (GIS) is based on the first and only Russian Imperial Census of 1897 and the First All-Union Census of the Soviet Union of 1926. The GIS features vector data (shapefiles) of allprovinces of the two states. For the 1897 census, there is information about linguistic, religious, and social estate groups. The part based on the 1926 census features nationality. Both shapefiles include information on gender, rural and urban population. The GIS allows for producing any necessary maps for individual studies of the period which require the administrative boundaries and demographic information.
Existing approaches suggest that IT strategy should be a reflection of business strategy. However, actually organisations do not often follow business strategy even if it is formally declared. In these conditions, IT strategy can be viewed not as a plan, but as an organisational shared view on the role of information systems. This approach generally reflects only a top-down perspective of IT strategy. So, it can be supplemented by a strategic behaviour pattern (i.e., more or less standard response to a changes that is formed as result of previous experience) to implement bottom-up approach. Two components that can help to establish effective reaction regarding new initiatives in IT are proposed here: model of IT-related decision making, and efficiency measurement metric to estimate maturity of business processes and appropriate IT. Usage of proposed tools is demonstrated in practical cases.