Software & Systems

Articles of journal № 4 at 2015 year.

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31. Finding sloutions by the modified Rete algorithm for fuzzy expert systems [№4 за 2015 год]
Authors: Mikhailov I.S., Zaw Min Htike
Visitors: 8909
The paper considers the basic concepts of fuzzy production expert systems. Fuzzy production expert systems are based on a set of rules presented in terms of linguistic variables. The authors suggest the developed Rete algorithm modification for a fuzzy rule base as a fuzzy inference tool. This modification accelerates systems operation due to a single computing of the same conditions in the rules. It also formulates the rules and conclusions in the limited natural language. The modified Rete algorithm formal decision tree model for a fuzzy production knowledge base consists of a set of vertex-conditions, vertexsolutions, the relationship between vertices and relations to describe the fuzzy expert system rules. The created algorithm processes the rules from the fuzzy rule base and converts them into the decision tree modified Rete algorithm formal model. Rete algorithm modification is different from a classical algorithm as it is used for fuzzy variables. Therefore, each stage of the algorithm includes building the decision tree vertices fuzzy truth values using fuzzy operators. This allows formulating the conditions and consequences in the rule base, as well as the solutions in the limited natural language. The same conditions are combined during decision tree construction. It accelerates decision tree processing comparing to sequential viewing of expert system rules. The paper describes an operating example of the production fuzzy expert system, which works on the basis of the proposed Rete algorithm modification. It also displays the effectiveness of the proposed method.

32. Data replication in hierarchical information systems with unstable node connectivity [№4 за 2015 год]
Author: Sorokin V.E.
Visitors: 8144
A particular feature of many hierarchical information systems (IS) with relational databases (DB) in their nodes as the core is impermanent communication between the nodes. It prevents classical use of a centralized or distributed database and assigns additional special message exchange and data consolidation functions including external sources to special software, which solves system functional tasks. Replication of required fragments of other IS nodes DB in a local DB consolidates with information from external sources. It allows to simplify and increase harmonization of various IS nodes software. The article proposes an approach to original DB structure transformation based on creating separate for different data sources inherited from source tables. The approach is adapted to asynchronous “master/slave” replication of hierarchically related DB. The paper shows the possibility of using flags and procedures managed by triggers to implement various strategies for data consolidation, as well as a simple adaptation of the original software to solve IS functional problems on the converted DB. There is an example of the described approach implementation for widespread and used in many domestic certified software tools of an object-relational database management system PostgreSQL with an asynchronous “master/slave” replication system Slony-I. There is a possibility to overcome limitations of an asynchronous “master/slave” replication system using dblink support modules of session connection to other DB and postgres_fdw foreign-data wrapper, as well as replication system joint using with these modules on the converted DB.

33. Representativeness of Intel Sandy Bridge performance counters based metrics for memory access latency analysis [№4 за 2015 год]
Authors: Ivanov E.Yu., Kosyakov M.S.
Visitors: 9054
This paper examines the representativeness of metrics based on Intel Sandy Bridge performance event counters and memory access latencies for data processed in RAM. It contains detailed overview and analyses of frequently used metrics recommended by Intel documentation. The authors have implemented a synthetic test application, which allows measuring memory access latencies for serial, per-page and random memory accesses and different sizes of working set and its elements processed by test application. The paper describes an approach to access performance event counters based on Linux perf utility. The test presented memory access latencies and calculated metrics based on performance event counters. The experimental studies showed that CPI, SCPI and PSRC metrics recommended by Intel and cache-miss ratio with serial memory access have linear dependency with measured memory latencies. Besides, the metrics values change proportionally to the change of memory latencies with the coefficient close to one. The random access results showed that most efficient metric for performance is the number of cycles wasted on bus waiting for data, because it always has high representativeness of memory access latencies and does not depend on data location. According to authors’ analyses, this metric is the most useful to evaluate memory access performance optimization efficiency. The results showed that the metrics considered in this paper can be used to analyze memory characteristics of application, which process data in RAM.

34. Textured planet model visualization system for space experiments simulation [№4 за 2015 год]
Author: Timokhin P.Yu.
Visitors: 8428
A modern tool to train space experiments related to the planet observation from a circumplanetary orbit is real-time visualization of virtual 3D planet model with detailed textures based on satellite images. Studies show that the size and memory space required for such textures significantly exceeds the capability of modern graphics accelerators (extra-large textures). This does not allow loading such textures in video memory completely and their hardware processing. This article describes a technology and software implementation which allows real-time visualizing of extra-large planet textures divided into small pieces of an equal size (pages). The key idea of the proposed technology is to reduce time costs for visible pages selection using GPU parallelizing computations by means of developed shader programs. The technology provides texture detailing of the simulated planet surface to fit the screen resolution. It also allows real-time visualizing multiple extra-large textures with different initial resolution on a virtual planet surface. The proposed technology is implemented in the planet texture visualization software package, which can be integrated in an external application. The created software package is also equipped with a module which calculates a observer\'s orbital position, as well as a user interface to control an observer\'s flight. The paper considers testing of the implemented software package as a part of 3D virtual scene visualization system. The results show that it meets all the requirements. The developed software package can be used both to improve features of existing simulators for space scientific experiments and to build new promising ones.

35. Comparison analysis and task classification according to cargo optimal placement in restricted space [№4 за 2015 год]
Authors: Pogorelov A.S., Andreev D.A., Panfilov A.N.
Visitors: 6123
The paper is devoted to the problem of objects optimal placement in restricted space. This problem belongs to the class of cutting and packing problems. The paper formulates the common cutting and packing problem. It also describes the approach to such problems classification and criteria, which are the basis of the typology and the main categories of the problems. The scientific researches review shows that similar problems arise in various domains and these problems have various features as a specificity of a problem domain. The authors consider several problems of cargo optimal placement, which have some similarities with the problem of cargo placement on a transport spacecraft. They compare considered problems to the problem of cargo placement on the transport spacecraft according to common characteristics of these problems. Furthermore, each problem under consideration is assigned to one of the classes in terms of the given typology. As a result of a comparison analysis, there is a conclusion that there is no any universal decision method for the optimal placement problem. There are some particular features and restrictions for any real problem, which must be considered. The authors set a task of development of a new method to find the optimal cargo placement. This method must consider any specific features of the problem domain related to spacecrafts.

36. Ergonomic testing of a manned transport spacecraft for crew interface design and training [№4 за 2015 год]
Authors: Serov M.V., Kukin O.N., Yanyushkin V.V., Radchenko V.M., Kharagozyan R.K.
Visitors: 10571
The article considers basic hardware and software solutions for ergonomic testing of new generation spacecraft. It is supposed to create a stand for ergonomic design and pilot testing of crew interfaces: display formats options to inform the crew, a new joystick to control orientation and movement. The article provides a functional composition of the stand and two main operation modes to prepare experimental data and their validation on the basis of software and hardware platforms. These are the ergonomic features of such perspective control devices as orientation and motion control handle on the one hand and various options of information support for the crew using the latest transforming cosmonaut’s console on the other hand that are the most important. All the works are performed along with the development and creation of a unique product. The article describes the main mechanical features of building cosmonauts’ workplace that enable easy assembling and disassembling of the product, its transportation, adaptations and update with regards to emerging requirements and conditions of use. The specialized software provides a number of tasks with remote monitoring and management of new generation spacecraft systems from the workplace of the person in charge using wireless voice communications as well. All the components are unified into a correlated system; data exchange is performed via local computing network. The training hardware includes general purpose industrial objects adapted to the use in the ergonomic stand.

37. Kalman filter as a method of secondary processing of GLONASS system information [№4 за 2015 год]
Authors: Bolodurina I.P., Nugumanova A.A., Reshetnikov V.N.
Visitors: 13424
The paper discusses methods of positioning a land vehicle based on secondary processing of information from GLONASS satellite navigation system. Vehicle positioning accuracy depends on many factors including the method of finding the coordinates. It is one of the indicators of vehicle effective control. Therefore, one can quickly control the vehicles movement, their actual value and the fuel consumption accuracy. The publications devoted to the problem of dynamic objects positioning, as a rule, do not describe mathematical models and algorithms, they just display the final results. In fact there are no sources, which can clearly describe an algorithmic scheme suitable for developing software. This is due to the fact that the software is a trade secret or an intellectual property. In contrast to existing methods of mobile objects control and monitoring, the authors have developed a Kalman filter algorithm step by step. It increases the positioning accuracy of a land vehicle. The algorithm is a basis for application software, which determines the land object location in real-time and post-processing mode. The paper discusses the cases of mobile and stationary state of a land vehicle. Each case shows using Kalman filter algorithm and the least squares method to enhance positioning accuracy. There is a comparative characteristics of these methods on the basis of selected statistical criteria. The authors set the most accurate method of positioning mobile and stationary objects.

38. Equational characteristics of LTL formulas [№4 за 2015 год]
Authors: Korablin Yu.P., Shipov A.A.
Visitors: 8974
sian Federationn State Social University, Vilgelma Pika St. 4, Moskow, 129256, Russian Federation) Аbstract. Day by day software systems are becoming more and more complex. Therefore, we need to have some useful instruments to check their capability according to specifications, especially large distributed software systems. Nowadays, to describe the verifying model conditions it is common to use such mechanisms as linear temporal logic (LTL) and computational tree logic (CTL). However, experience has proven that these mechanisms can help formulate only a relatively small set of the same-type conditions. It can complicate the verification process or make it ineffective for a particular system model. Correct formulation of model\'s verifying properties is the key problem, as the whole verification process depends on it. Thus, to achieve best results it is required to use powerful tools and techniques, which clearly formulate a wide class of verifying properties. The article describes a mechanism that can significantly extend the group of formulated conditions according to verifiable models. This effect can be achieved by expanding LTL expressivity using the proposed method, which increases the efficiency of the verification process. The article provides a set of illustrative examples of the method, which demonstrates its practical application. The article also provides the example of properties verification for a particular model based on the proposed method.

39. Ergonomic voice interface to control an anthropomorphic robot [№4 за 2015 год]
Authors: Mikhaylyuk M.V., Torgashev M.A., Omelchenko D.V.
Visitors: 8414
Anthropomorphic robots (robots structurally similar to human beings) are widely used in various fields of scientific and economic activity. It is due to psychological factors, as well as to the fact, that many man-made objects are adapted to manipulate by human hands. However, ergonomic control of such robots is a serious and pressing problem. Standard computer interface devices (keyboard, mouse, joystick etc.) do not provide a sufficient level of ergonomics. Using control panels is also difficult because each control panel element usually affects one joint of the robot. Or alternatively, exoskeletons are often used for control. They are rigid articulated construction worn by an operator and match the organization of human body. An exoskeleton allows implementing the so called copying control mode when the robot will follow the operator’s exact movements. However, the exoskeleton is often difficult to use, either because of its great weight, or because it is impossible to use it in the suit. This paper proposes a voice interface to control a robot. The idea is that when the operator’s command is pronounced it is recognized and then in case of success the prepared script starts running, so the robot performs the specified action. Testing of the proposed methods and algorithms showed that it is possible to use them as an ergonomic interface of anthropomorphic robots\' voice control.

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