Software & Systems

Articles of journal № 2 at 2017 year.

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21. On modeling of electricity nodal prices [№2 за 2017 год]
Author: Khalilov E.D.
Visitors: 9985
In terms of power supply system reforms in various countries, including Azerbaijan, there is a possibility of using renewable energy sources in the electrical network. Relevant studies began to trace the power of “green” power genera-tors and harmonic distortion sources. Electrical energy trading on the wholesale market uses market mechanisms, such as a day-ahead market, a balancing market, a market of regulated contracts, and free electricity sale and purchase agreements. As generating stations and other suppliers have variable cost of electricity, this fact leads to solving the relevant problem of determining nodal prices. Nodal prices show a electricity unit cost purchased in a node. Each node price includes such components as a marginal price of a balancing node, losses in transmission lines, power line price restrictions. Calculation of these components requires development of the appropriate software. The paper describes the developed algorithm for simulation of nodal prices. This algorithm is implemented as a program in MATLAB system to determine nodal prices in the electricity market. The software efficiency is tested at different test schemes. In particular, this article presents the results of nodal price calculations using the example of 7-node test scheme of electrical network.

22. Design principles of modular software architecture in aviation [№2 за 2017 год]
Author: Chizhikova L.A.
Visitors: 12266
Software development is a quite difficult and laborious process, which is based on correct and reliable architecture design. Distribution and coordination of duties when working in a group of developers is often a quite difficult and re-sponsible decision due to affection the main result of development. Nowadays, with technological development the control and functionality of aircraft avionics requires more software creation. The role of software development and management is also increasing in the flight simulation and testing equipment fields. More and more tasks are transferred from hardware to software. The article provides the analysis and identification of basic aviation software design aspects, the comparison between the civil aircraft software design architecture and flight simulation software architecture. In order to present a unified software architecture model, the authors made a research on papers on software architecture design in Russian companies, which make Flight Simulation devices and onboard aircraft software architecture. There is also a comparison of these solutions and their commonality. Furthermore, the article considers a model, which is successfully used in software development by Rockwell Automation Company, and makes a research among the works of Delft Technical University on the described topic. The paper proposes a mathematical description of modular software product architecture, which is oriented to the aviation industry. The proposed approach allows unifying a development process, reducing the time and labor of software development, adding innovations without existing structure transformation if the software product is made using the described solution.

23. The empirical risk minimization principle based on average loss aggregating functions for regression problems [№2 за 2017 год]
Authors: Z.M. Shibzukhov, D.P. Dimitrichenko, M.A. Kazakov
Visitors: 6865
The paper proposes an extended principle of empirical risk minimization to solve the regression problem. It is based on using aggregate functions instead of arithmetic mean to calculate risk. This can be justified if the loss distribution of emissions is significant or distorted, causing a shift in the risk assessment of the average loss from the very beginning. Therefore, in such cases, when optimizing characteristics in the regression problem the robust estimate of average value-at-risk should be initially used. Such intermediate risk assessment can be constructed using avg functions, which are the solution to the problem of penalty function minimization in case of mean deviation. This approach allows, on one hand, to determine a much broader class of secondary functions, and, on the other hand, to determine the average differentiable functions that approximate the average non-differentiable functions, such as a median or quintile. As a result, it is possible to construct gradient methods for solving the regression problem that, in a sense, can approximate robust techniques such as Least Median and Least Quantile. This paper proposes a new gradient scheme for solving the minimization problem of the intermediate risk. It is an analog of the used in the SAG algorithm circuit when the risk is calculated by arithmetic mean. An illustrative example presents the construction of robust procedures for characteristics assessment in a linear regression based on the use of the avg function, which approximates the median.

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