Software & Systems

Articles of journal № 1 at 2019 year.

Order result by: Public date | Title | Authors

21. Comparison the efficiency of adaptive algorithms of traffic control in AnyLogic [№1 за 2019 год]
Author: S.A. Andronov
Visitors: 5546
The paper considers the issues of traffic flow simulation and management depending on traffic intensity. There are some simu-lation models that are developed and implemented in AnyLogic. These models relate to adaptive transport flow control algo-rithms such as soft programming of traffic lights using fuzzy logic; queue-out; search for discontinuities in a transport flow; search optimization using Webster's formula; direct minimization of transport delays in the simulation process; soft program-ming of traffic lights using fuzzy logic. During simulation modeling, including traffic conditions at the actual metropolis intersections, the author compares a possi-ble effect from applying the above adaptive algorithms with the operation of a traffic light with a fixed phase duration for dif-ferent traffic load. The paper presents diagrams of efficiency bounds of the considered algorithms in a wide range of parameter changes. The compared algorithms are sorted by the effect of the intersection capacity in the received initial data ranges. The simulation results show that the installation of adaptive control systems allows reducing car standing time (engine load, gasoline consumption, harmful emissions) in comparison with usual traffic lights at average from 5% to 50%. The optimization principle of constructing adaptive control shows a much bigger effect of increasing intersection capacity comparing with the work of algorithms such as “passing queues” and “break searching” in a wide range of changes in traffic flow intensities. The traffic light algorithm with fuzzy logic occupies an intermediate position. The “sensitivity analysis” experiment in AnyLogic demonstrates a fairly flat dependence of the transport flow optimization criterion from the optimal intensity value of the passing vehicles.

22. The unified representation of LTL and CTL logics formulas by recursive equation systems [№1 за 2019 год]
Authors: Korablin Yu.P., Shipov A.A.
Visitors: 6143
Nowadays, to solve the formal verification problem using the Model Checking method, the following logics are often used: the linear-time temporal logic (LTL), the computation tree logic (CTL) and CTL* that combines the capabilities of both other logics. However, each of these logics has its own disadvantages, limitations and expressiveness problems due to their syntactic and se-mantic features. Therefore, there is no universal temporal logic at the moment. The authors are convinced that special representations, which are based on systems of recursive equations in regard to tem-poral logics, can extend their expressiveness, as well as unify their syntax. Thus, they allow building their common and uniform notation. The paper proposes and considers a special RTL notation that is based on systems of recursive equations and the accus-tomed LTL and CTL semantic definitions. The notation is intended to solve the problem of unification of expressiveness of both logics, which in turn expands the expressiveness each one of them. The unification of their syntactic structures will give an opportunity to develop a uniform approach for the Model Checking problem. The authors provide a detailed definition of the RTL notation; give corresponding axioms and theorems. The paper also rep-resents a number of examples and statements that clearly demonstrate the RTL expressiveness capabilities. The purpose of the paper is to demonstrate key features and capabilities of the RTL notation, which are the basis for the au-thors' further research on solving the problem of system models verification.

23. Energy consumption management in data storage process when choosing the size of a data physical block [№1 за 2019 год]
Authors: Tatarnikova, T.M., E.D. Poymanova
Visitors: 5914
The papers considers the function hierarchy of data storage at a physical level. At the first level, there are functions to maintain a steady state of minimum data storage units. The number of stable states of data storage minimum unit affects the number of stored data bits. It is shown that minimum data storage units differ depending on the file type and the medium type. There is an expression that allows estimating the minimum energy required to convert a minimum storage unit. At the second level, there are functions to combine the minimum units of data storage into physical data blocks. The paper shows the structure of a physical unit. There is an example of changing a physical block size. It demonstrates the possibility of adjusting a physical block size depending on the stored information type and requirements for the storage system. When a phys-ical block increases, the metadata stored in a medium decreases, and thus the efficiency of using the media capacity increases. At the third level, there are functions to unite the physical blocks into logical data blocks. The logical block size depends on the capabilities of the installed file system and is set when formatting. At the file level, there is addressing of data bits, physical and logical blocks, thereby the data bits are logically combined into a file. The paper presents the results that demonstrate a sig-nificant reduction in energy consumption with a data block size increase and a metadata volume decrease compared to energy consumption when maintaining the original file.

24. Formation of a safety barrier for a spacecraft under spaсe debris impact using fuzzy logic methods [№1 за 2019 год]
Authors: V.K. Kemaykin, I.V. Kozhukhin
Visitors: 4756
The paper proposes the algorithm to form a safety barrier from space debris impact for a spacecraft independent operation. The efficiency of the safety barrier depends on responsiveness, economy and efficiency (reliability) of protective measures that form the safety barrier. Nowa-days, the safety barrier includes measures implemented in a spacecraft with the human operator in an automatic mode. For this purpose, space debris must be detected in time and the time to a predicted collision must be sufficient to make a decision (about 28 hours). Then an operator can evaluate and consider the importance of parameters and form a proper barrier. An automatic avoidance maneuver is performed for other cases when there might be a collision with space debris. This maneuver associates with changes in the orbital parameters of a spacecraft. The task of safety barrier efficiency estimation appears under the conditions of autonomous orbital functioning of a spacecraft. This task should take into account environmental conditions, when safety barrier is formed automatically in real time mode on board. The developed knowledge base of parameter importance allows estimating the safety barrier effectiveness taking into account the situa-tion for each potentially dangerous (by the collision criterion) object in the automatic operation cycle of an on board spacecraft computer. The requirement for spacecraft functioning autonomy and the countering of a possible danger from a space debris impact is based on the use of the fuzzy set theory including the principle of fuzzy merging of objectives and restrictions. Initial estimates of a safety barrier effective-ness implement the principle of a guaranteed result with estimable criteria balance. Real-time estimation of the effectiveness takes into ac-count the importance of safety barrier parameters, which are sets of rules from the knowledge base about the required and existing effective-ness (reliability) restrictions, time and fuel consumption for implementing potential safety barriers. The obtained results show that the effectiveness of potential safety barriers may vary in real conditions depending on the importance of the parameters.

◄ ← Preview | 1 | 2 | 3